Mechanical thrombectomy has demonstrated clinical benefit in acute ischemic stroke caused by anterior-circulation large-vessel occlusion, but several biological levels can remain separated. Reopening the parent artery is not identical to angiographic reperfusion, adequate tissue-level perfusion, restored microvascular flow, preserved oxygen delivery or neurological recovery. After recanalization, downstream vessels may remain hypoperfused, exhibit uneven capillary flow or shunting, become hyperperfused through failed autoregulation, leak across the blood–brain barrier, or be compressed by edema. The review therefore treats incomplete tissue-level reperfusion as an intermediate imaging and tissue phenotype between technical success and clinical outcome. It emphasizes that temporally aligned measurements are needed to test whether particular biological processes precede or accompany the observed perfusion abnormalities.

The endothelial glycocalyx occupies the luminal surface of blood vessels and includes glycosaminoglycans, membrane-bound proteoglycans, glycoproteins and associated plasma proteins. Its composition and thickness vary by vascular bed, flow state, inflammation, age and disease context. In the brain, it operates within the specialized blood–brain barrier and neurovascular unit, alongside endothelial cells, pericytes, basement membrane, astrocytic endfeet, microglia, neurons and extracellular matrix. The glycocalyx is related to, but not synonymous with, either the blood–brain barrier or the neurovascular unit. An intact layer can limit direct contact between circulating cells and the endothelial membrane, support antithrombotic and anticoagulant surface properties, regulate permeability and participate in shear-dependent nitric-oxide signaling. Experimental cerebral ischemia work links glycocalyx integrity to suppression of endothelial transcytosis and preservation of barrier function, while brain-aging research links glycocalyx dysregulation and mucin-domain glycoproteins to blood–brain barrier stability. These findings strengthen the anatomical rationale for examining the layer after thrombectomy but do not establish that its disruption causes human post-thrombectomy no-reflow.

The proposed two-stage model begins with reduced endothelial-surface resilience. In this review, cardiometabolic vulnerability is a conceptual host context rather than a diagnosis: chronic metabolic, inflammatory, renal and vascular stress may reduce baseline resilience before the ischemic event. Cross-disease vascular evidence associates diabetes and hyperglycemia with oxidative and inflammatory stress and impaired nitric-oxide availability, and hypertension and dyslipidemia with altered mechanotransduction, abnormal hemodynamic stress and inflammatory activation. Renal dysfunction may influence systemic endothelial homeostasis, inflammation and clearance of circulating glycocalyx-related biomarkers, but that relationship has not been validated as a cerebral post-thrombectomy mechanism. Experimental and translational brain evidence also supports aging-related alterations in glycocalyx-associated barrier biology. Indirect clinical studies link cardiometabolic risk states to unfavorable outcomes after endovascular therapy, although they do not identify glycocalyx injury as the operating pathway. The two-stage hypothesis therefore proposes that pre-existing vulnerability may lower the capacity to withstand ischemic and reperfusion-related stress, while acute occlusion adds endothelial hypoxia, ATP depletion, acidosis, ionic dysregulation, low shear and inflammatory signaling before the artery is reopened.

Several acute triggers could converge on the vulnerable luminal interface. Restoration of oxygen and substrate produces abrupt shear changes, reactive oxygen species, leukocyte recruitment, thrombin generation and cytokine signaling that may promote enzymatic shedding of glycocalyx components. Complement activation contributes to cerebral ischemia–reperfusion injury in experimental models, while experimental thrombectomy models implicate succinate-associated metabolic injury, but neither process is specific to the glycocalyx. Stent retrievers, aspiration catheters, repeated passes, clot–device interaction and rapid flow restoration can perturb the vessel wall and endothelium; direct visualization of cerebral glycocalyx damage from these devices in patients remains unavailable. Distal clot migration or residual microemboli can also create patchy low-flow territories and sustain thromboinflammation. These processes may occur upstream, downstream, in parallel with or independently of glycocalyx dysfunction, supporting a network model rather than a single linear cascade.

Loss of the glycocalyx’s normal functions could amplify established no-reflow mechanisms. By separating leukocytes from endothelial adhesion platforms, an intact layer discourages rolling, adhesion and capillary stalling. In a mouse recanalization model, neutrophils obstructed a substantial fraction of capillaries after upstream flow was restored, supporting leukocyte plugging as a no-reflow mechanism, but the experiment did not establish glycocalyx shedding as the initiating event in human thrombectomy. Glycocalyx disruption could also expose procoagulant surfaces and reduce local antithrombotic capacity, potentially contributing to platelet adhesion, fibrin deposition and microthrombosis. Primary experimental stroke work has demonstrated capillary fibrin deposition and stacked erythrocytes after recanalization or thrombolysis, supporting a thrombotic component of no-reflow, while the share attributable specifically to cerebral glycocalyx dysfunction remains unknown.

Other proposed interactions involve mechanosensing, barrier stability and capillary-flow distribution. Because glycocalyx-dependent mechanotransduction links shear stress to endothelial nitric-oxide production, surface damage could make endothelial sensing of restored flow more heterogeneous and potentially contribute to vasomotor mismatch or impaired autoregulation. Imaging of cerebrovascular reactivity after successful endovascular treatment supports persistent hemodynamic dysfunction, but it does not identify glycocalyx causality. Experimental stroke studies associate glycocalyx disruption with increased endothelial transcytosis and blood–brain barrier permeability, while human thrombectomy imaging associates barrier disruption or increased permeability with edema, hemorrhagic transformation and adverse tissue states; neither evidence type is glycocalyx-specific. Pericyte-mediated capillary constriction is well supported experimentally after cerebral ischemia, yet direct coupling between glycocalyx injury and pericytes after thrombectomy has not been demonstrated. Theoretical and imaging work also indicates that heterogeneous capillary transit can impair oxygen extraction even when total cerebral blood flow is not uniformly reduced. Patchy adhesion, microthrombosis, vasomotor mismatch and barrier leakage are possible contributors, but perfusion-metabolic validation is required in thrombectomy populations.

Human biomarker studies do not yet resolve these questions. Syndecan-1, heparan sulfate and hyaluronan can be sampled repeatedly and may reflect shedding products from endothelium, but peripheral concentrations are not brain-specific. They can also derive from the lung, kidney, liver, gut, systemic inflammation, clearance and vascular instrumentation. Paired intracranial and peripheral sampling in large-vessel occlusion cohorts has shown spatial and temporal heterogeneity in syndecan-1, indicating that local distal-occlusion signals and peripheral venous concentrations cannot be assumed to be synchronized. Longitudinal endovascular-therapy and thrombectomy cohorts also show that syndecan-1 behavior depends on sampling time and clinical context. A thrombolysis-treated cohort found higher plasma syndecan-1 associated with unfavorable outcome, whereas a mechanical-thrombectomy cohort reported that lower postoperative-day-1 syndecan-1 was associated with worse prognosis. Prospective 2026 measurements before recanalization and at 24 and 48 hours found treatment-group differences across serial assessments but no direct association between syndecan-1 and either the National Institutes of Health Stroke Scale or the modified Rankin Scale. These divergent results show why an isolated circulating concentration cannot be translated directly into “more” or “less” cerebral glycocalyx injury.

Evidence that downstream microcirculation remains therapeutically actionable does not validate a glycocalyx-specific explanation. The phase 2b CHOICE trial suggested a higher frequency of excellent outcome with intra-arterial alteplase after successful thrombectomy, although it was stopped early and requires replication. The PEARL study subsequently reported a higher proportion of 90-day modified Rankin Scale scores of 0–1 with intra-arterial alteplase after successful endovascular reperfusion in selected patients. Phase 1b/2a data on intra-arterial tenecteplase support dose selection and safety for further study but do not establish definitive efficacy. These trials support the therapeutic actionability of the post-endovascular microcirculation; they do not establish glycocalyx repair as the operative mechanism. Strategies directed at oxidative stress, complement activation, metabolic stress, endothelial inflammation, blood–brain barrier dysfunction, edema, glucose control, blood-pressure variability and systemic inflammatory burden may influence the luminal endothelial surface indirectly, but their effects are pleiotropic and cannot be labeled glycocalyx-specific. Sulodexide, heparanase-related strategies, glycosaminoglycan restoration and preservation of hyaluronan or heparan sulfate are conceptually relevant interventions, yet supporting evidence comes mainly from diabetes, sepsis, non-cerebral vascular injury, animal models or endothelial-cell systems. They remain experimental, cross-disease or trial-enabling candidates rather than validated post-thrombectomy treatments.

The authors propose a prospective cohort of adults with anterior-circulation large-vessel occlusion who achieve near-complete or complete angiographic reperfusion after mechanical thrombectomy. Serial blood samples would be collected before treatment, immediately after recanalization, one to six hours later and at 24 hours, with local arterial sampling only where technically and ethically feasible. Biomarker trajectories would be aligned with immediate or early perfusion imaging, blood–brain barrier assessments, 24-hour final infarct volume and infarct growth, edema, hemorrhagic transformation, early neurological status and 90-day functional outcome. Researchers would prespecify an imaging-defined incomplete-reperfusion phenotype, such as abnormal parenchymal contrast-transit delay after final angiographic reperfusion or residual perfusion abnormality one to six hours after thrombectomy, and test a pathway from biomarker dynamics to impaired microvascular reperfusion, tissue-injury expansion and clinical outcome. Cardiometabolic factors would be modeled as confounders and potential effect modifiers, while competing mechanisms such as distal embolization, microthrombosis, pericyte contraction, endothelial swelling, complement activation and inflammation would be examined in parallel.

The review synthesizes targeted English-language literature available through 30 April 2026 from PubMed/MEDLINE, Web of Science, Embase and Google Scholar. Its final set contains 53 publications, including 38 primary clinical, experimental or modeling reports and 15 reviews, meta-analyses or narrative papers. The authors separated direct human thrombectomy evidence from indirect biomarker and imaging studies, experimental cerebral evidence, cross-disease vascular evidence and hypothesis-generating inference. Because this was a narrative review rather than a systematic review or meta-analysis, it did not include a PRISMA workflow, formal risk-of-bias assessment or prospectively retained record-level screening counts. The framework therefore cannot claim systematic completeness or causal certainty. Its near-term value is to specify experiments that could support, refine or reject the hypothesis: serial, compartment-annotated biomarkers, temporally aligned perfusion and barrier imaging, tissue endpoints and explicit modeling of host vulnerability and competing mechanisms. Until direct cerebral imaging and tightly timed human studies establish the sequence of events, glycocalyx dysfunction remains a biologically plausible amplifier and organizing research framework, not an established cause or a ready-made therapeutic target.

Subject of Research: Endothelial glycocalyx dysfunction as a proposed amplifier of microvascular reperfusion failure after mechanical thrombectomy

Article Title: Endothelial glycocalyx dysfunction in the setting of mechanical thrombectomy: a conceptual link between cardiometabolic vulnerability and microvascular reperfusion failure

Article References: Wu, X., Mi, S., Ma, J., Xing, Y., Li, G., Cao, Z., & Xiong, X. (2026). Endothelial glycocalyx dysfunction in the setting of mechanical thrombectomy: a conceptual link between cardiometabolic vulnerability and microvascular reperfusion failure. Frontiers in Neurology, 17, Article 1919445. https://doi.org/10.3389/fneur.2026.1919445

Image Credits: AI Generated

DOI: 10.3389/fneur.2026.1919445

Keywords: mechanical thrombectomy, endothelial glycocalyx, microvascular reperfusion, no-reflow, acute ischemic stroke, cardiometabolic vulnerability, syndecan-1, blood–brain barrier, narrative review, Endothelial, glycocalyx, dysfunction

The study, led by Assistant Professor Priya Dipta of Nagoya University’s Institute for Glyco-Core Research in Japan and Professor Morten Thaysen-Andersen of Macquarie University in Australia, with collaborators including Daisuke Kasugai, Hironoshin Onizuka and colleagues at Nagoya University Graduate School of Medicine, was published in the Proceedings of the National Academy of Sciences of the United States of America. The team’s findings center on a layer of the cell surface that has long been overlooked in cancer immunology: the glycocalyx, a dense coating of proteins and lipids studded with sugar chains that mediates how cells communicate with one another and with their surroundings.

The sugar chains of the glycocalyx are frequently capped with sialic acid, a negatively charged sugar that influences everything from cell adhesion to immune recognition. Sialic acids attach to underlying glycans through two main linkage types, designated α2,3 and α2,6. Altered sialylation is already known to help cancer cells evade immune surveillance, but how these linkages change as macrophages shift between pro-inflammatory and anti-inflammatory states had remained unclear. To answer that question, the researchers isolated monocytes from healthy donors and differentiated them in the laboratory into tumor-fighting, pro-inflammatory macrophages and tumor-promoting, anti-inflammatory macrophages, then compared the sialic acid linkages displayed on their surfaces.

The contrast was dramatic. Using mass spectrometry and glycan-specific protein staining, the team found that tumor-fighting macrophages carried predominantly α2,3-linked sialic acids on their surface N-glycans. In tumor-promoting macrophages, the situation was nearly reversed: roughly ninety percent of their sialic acids were attached through the α2,6 linkage. This linkage switch, the researchers concluded, is a hallmark of the macrophage transition from a state that attacks tumors to one that tolerates and even supports them.

Perhaps the most visually striking discovery came from fluorescence microscopy. The tumor-promoting macrophages extended long, branching protrusions coated with α2,6-linked sialic acid, which the researchers named sialo-protrusions. These structures reached up to 800 micrometers from the cell body, an extraordinary distance for cellular extensions, and formed mesh-like networks by connecting neighboring cells. Tumor-fighting macrophages displayed far fewer of these structures. Intriguingly, the sialo-protrusions showed no evidence of actin, the protein that typically forms cellular extensions such as filopodia and lamellipodia. Instead, they carried α2,6-sialylated glycoproteins on their surface, suggesting they represent a previously unrecognized class of cellular projections distinct from known actin-based structures.

The search for the molecular switch behind this remodeling led the team to an enzyme called ST6GAL1, which catalyzes the addition of sialic acid in the α2,6 configuration. Only the tumor-promoting macrophages expressed high levels of ST6GAL1, making it a prime suspect in the linkage switch. When the researchers silenced the enzyme using siRNA, the effects were immediate and widespread. The sialo-protrusions broke apart and shortened, the macrophages moved less, and they interacted less with one another, indicating that these sugar-coated extensions are functionally important for macrophage motility and communication rather than mere decoration.

The consequences extended to the cancer cells themselves. With ST6GAL1 suppressed, the tumor-promoting macrophages made less contact with colorectal cancer cells in laboratory co-cultures, and the cancer cells grew much more slowly. This suggests that sialo-protrusions help macrophages migrate, communicate with cancer cells, and support tumor growth through those physical contacts. Removing the enzyme that builds the α2,6 linkages appears to sever a critical line of communication between immunosuppressive macrophages and the tumor.

Even more remarkably, suppressing ST6GAL1 did more than disable the protrusions. The treated tumor-promoting macrophages began to resemble their tumor-fighting counterparts in shape, in the cytokines they expressed, and in their phagocytic ability, the capacity to engulf targets. In other words, targeting a single enzyme appeared to shift the cells’ overall state back toward the pro-inflammatory, tumor-attacking program. The finding raises the possibility that glycocalyx remodeling could become a therapeutic lever for reprogramming the immune microenvironment of tumors rather than simply blocking one interaction at a time.

To confirm that the laboratory observations reflected biology in real patients, the team examined tumor tissue from patients with advanced colorectal cancer. The same pattern held: tumor-promoting TAMs carried more α2,6-linked sialic acid, while tumor-fighting TAMs displayed more α2,3 linkages, mirroring the results from the donor-derived cells. This consistency between controlled experiments and patient samples strengthens the case that the sialyl linkage switch is a genuine feature of the tumor immune landscape rather than an artifact of cell culture. Dipta noted that the findings provide a new perspective on how remodeling of the immune cell glycocalyx may influence the tumor microenvironment.

Important questions remain before the discovery can be translated into treatment. The researchers emphasize that future studies must test ST6GAL1 inhibition in living organisms to evaluate whether it produces meaningful antitumor effects in the complex setting of a real tumor, where macrophages interact with many other immune and stromal cell types. The team also aims to identify the proteins that form the sialo-protrusions and to clarify exactly how these unusual structures mediate communication between macrophages and cancer cells. If those efforts succeed, they could open a new strategy for cancer immunotherapy: not boosting immune cells with checkpoint blockers alone, but chemically re-sculpting the sugar coat that tells macrophages which side to fight for. For now, the study offers a compelling proof of concept that the fate of tumor-associated macrophages may hinge, quite literally, on the fine chemical details of the sugars they display.

Subject of Research: Glycocalyx sialylation and macrophage polarization in the colorectal tumor microenvironment

Article Title: Shifting immune cells back toward cancer-fighting mode

Article References: Shifting immune cells back toward cancer-fighting mode. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: macrophages, tumor-associated macrophages, glycocalyx, sialic acid, ST6GAL1, colorectal cancer, tumor microenvironment, sialo-protrusions, glycosylation, cancer immunotherapy, Nagoya University, PNAS

The tumor ECM is far more than a passive wall. In healthy tissue, its composition of collagens, proteoglycans, glycosaminoglycans, laminins, and fibronectin is finely tuned to maintain homeostasis. In cancer, the matrix becomes a dynamic scaffold that promotes immune evasion, metastasis, and therapeutic resistance. Dense ECM obstructs the trafficking of drugs and immune cells, drives hypoxia, and fuels immunosuppressive signaling within the tumor microenvironment. Beyond the ECM, many tumors wrap themselves in a glycocalyx enriched in mucins and hypersialylated glycans, which physically blocks receptor-ligand interactions and engages inhibitory Siglec receptors on immune cells. The review argues that editing these barriers enzymatically could transform immunologically cold tumors into hot ones, but it also cautions that such remodeling is a double-edged sword requiring precise spatial and temporal control.

Among the most striking preclinical advances is the engineering of immune cells to produce heparanase, the only mammalian enzyme capable of cleaving heparan sulfate chains on heparan sulfate proteoglycans. Long-term ex vivo expansion of T cells downregulates heparanase expression, partly through p53-mediated repression, leaving CAR-T cells poorly equipped to burrow through matrix-rich tumors. When researchers co-expressed heparanase in CAR-T cells, the engineered cells showed robust tumor-eliminating activity in the presence of ECM, enhanced intratumoral accumulation, superior tumor control, and prolonged survival in animal models, without abnormal accumulation in the lung or liver. A parallel approach anchored an enzymatically active heparanase construct to the surface of NK cells, which restored penetration into tumor spheroids and improved tumor control in vivo, while the membrane-anchored design may help limit systemic enzymatic dissemination.

Hyaluronidase strategies have traveled furthest toward the clinic, though not without painful lessons. Hyaluronan accumulates densely in many tumors, including HER2-positive breast cancers and EGFR-positive head and neck cancers, where it limits antibody access and disrupts the immune synapses needed for antibody-dependent cellular cytotoxicity. The PEGylated enzyme PEGPH20 reached clinical trials, but the SWOG S1313 study found that combining it with modified FOLFIRINOX increased gastrointestinal and thromboembolic toxicity and was associated with inferior survival, while the HALO 109-301 trial raised response rates in pancreatic cancer without improving overall survival. These failures have pushed the field toward localized delivery: CAR-T cells engineered to secrete Fc-fused PH20 showed greater tumor regression in gastric cancer xenografts, dual-engineered cells co-expressing IL-7 and PH20 improved infiltration and survival in hepatocellular carcinoma models, and bioorthogonal click chemistry has been used to decorate CAR-T cells with hyaluronidase plus a pH-responsive anti-PD-L1 antibody.

Remarkably, hyaluronidase activity may do more than clear a physical path. Degradation fragments of high-molecular-weight hyaluronan activated CD103-positive dendritic cells through Toll-like receptor 4 signaling, enhancing CD8-positive T cell responses. Small extracellular vesicles carrying PH20 increased CD8-positive T cell infiltration and suppressed tumor growth in melanoma and breast cancer models, and when combined with anti-PD-L1 therapy, produced durable tumor suppression even in an autochthonous MMTV-PyMT model. A stimulus-responsive nanocarrier delivering hyaluronidase, interleukin-12, and anti-PD-L1 achieved sequential, tumor-triggered release in hepatocellular carcinoma models, depleting hyaluronan, reducing collagen deposition, and extending survival without inducing metastasis. Intratumoral hyaluronidase also boosted a nanovaccine regimen, markedly improving CD8-positive T cell infiltration and interferon-gamma production in melanoma models.

Collagen, the most abundant ECM component, presents a subtler challenge because its role is context-dependent. In pancreatic ductal adenocarcinoma, cancer cells produce an oncogenic type I collagen homotrimer that drives growth through integrin signaling, distinct from the heterotrimer made by cancer-associated fibroblasts. Because collagenase cannot distinguish collagen by origin, researchers engineered Escherichia coli Nissle 1917 bacteria, which preferentially colonize hypoxic tumor regions, to carry ROS-responsive nanocages releasing collagenase and anti-PD-L1 locally. This depleted oncogenic collagen, attenuated integrin-FAK signaling, increased CD8-positive T cell infiltration, and extended survival in orthotopic pancreatic cancer models. In another approach, CAR-T cells were fitted with collagenase nanogel backpacks decorated with a CXCR4 antagonist peptide, which simultaneously degraded matrix and freed T cells from CXCL12-mediated trapping, achieving complete tumor regression in some mice. Yet the review warns that indiscriminate collagen depletion can backfire: in pancreatic cancer models, depleting myofibroblast-derived collagen accelerated tumor progression and immunosuppression.

Perhaps the most unexpected recruit is nattokinase, a serine protease from Bacillus subtilis best known for its fibrinolytic activity in the Japanese fermented food natto. Repurposed for oncology, intratumoral nattokinase degraded fibronectin, improved tissue perfusion, reduced hypoxia, and indirectly suppressed cancer-associated fibroblast activity. In breast tumor xenografts, nattokinase pretreatment produced a sixfold increase in intratumoral CAR-T cell accumulation and superior therapeutic outcomes. However, the enzyme was administered locally, and its systemic pharmacokinetics, long-term safety, and allergenic potential as a bacterially derived protein remain insufficiently characterized.

The glycocalyx itself has become a target through sialidases and mucinases. Hypersialylation cloaks tumor cells, blocking NKG2D activating receptors and engaging inhibitory Siglecs. Antibody-sialidase conjugates, including trastuzumab fused to Salmonella Typhimurium sialidase (T-Sia 2), enhanced NK cell-mediated killing and delayed tumor growth in trastuzumab-resistant breast cancer models, while an anti-PD-1-sialidase conjugate preferentially desialylated PD-1-positive T cells and improved tumor control in melanoma. Sialidase has also been fused to bispecific T cell engagers and engineered into CAR-T cells secreting Clostridium perfringens neuraminidase, which preserved a naive-like phenotype and improved persistence. Encouragingly, E-602, a first-in-class engineered human sialidase, demonstrated tumor desialylation and early clinical activity in the Phase 1/2 GLIMMER-01 trial when combined with the anti-PD-1 antibody cemiplimab, marking the furthest clinical advance of any glycocalyx-editing strategy.

Mucin-targeting enzymes complete the toolkit. StcE, a mucin-selective metalloprotease from E. coli O157:H7, trims glycocalyx thickness by roughly ten nanometers enough to alter cancer-cell susceptibility to immune attack, and restored NK cell killing of mucin-rich tumors. Because high-dose systemic StcE caused platelet depletion and hemorrhagic toxicity in mice, an attenuated variant was fused to a HER2-targeting nanobody, reducing tumor burden and metastatic spread in mammary tumor models. Researchers also developed a modular leucine-zipper Zip-NK platform for controllable surface display of StcE and sialidase on NK cells, and nanovesicles co-displaying StcE with a CD47-targeting nanobody enhanced macrophage phagocytosis and tumor control while avoiding the toxicities of free enzyme.

The review closes with sobering translational caveats. Excessive matrix degradation may promote metastasis, off-target enzyme activity can damage normal tissues, and matrix reconstitution is rapid, with hyaluronan-rich matrices rebuilding within 24 hours after enzyme removal in vitro. Anti-drug antibodies have already limited repeated dosing of at least one sialidase construct, and microbial enzymes carry inherent immunogenicity risks that PEGylation and protein engineering have not fully solved. Biomarker-guided patient selection, combining substrate abundance with immune-exclusion profiling and spatial imaging, will be essential, since hyaluronan-high status alone failed to predict benefit in pancreatic cancer trials. Most strategies remain preclinical, but with only a handful of microbial enzymes explored so far, computational protein design and screening of the vast microbial world could rapidly expand the barrier-editing toolkit, potentially turning the tumor’s own fortress into its greatest vulnerability.

Subject of Research: Enzyme-mediated remodeling of the tumor extracellular matrix and glycocalyx to enhance immunotherapy in solid tumors

Article Title: Enzyme‐mediated remodeling of the extracellular matrix and glycocalyx to enhance immunotherapy in solid tumors

Article References: Mirmohammadsadegh, N., & Amin, M. (2026). Enzyme‐mediated remodeling of the extracellular matrix and glycocalyx to enhance immunotherapy in solid tumors. Bioengineering & Translational Medicine, Article e70180. https://doi.org/10.1002/btm2.70180

Image Credits: AI Generated

DOI: 10.1002/btm2.70180

Keywords: extracellular matrix, glycocalyx, immunotherapy, CAR-T cells, heparanase, hyaluronidase, collagenase, sialidase, mucinase, tumor microenvironment, drug delivery, cancer

Sepsis is the body’s extreme and dysregulated response to infection, a systemic event that floods the circulation with inflammatory signals and can push organs toward failure. Among its most insidious effects is damage to the endothelial cells, the thin layer of cells that lines every blood vessel and normally maintains a smooth, anticoagulant surface. When inflammation injures this lining, the vessel wall can flip from a protective state to a pro-clotting one. In some patients, this shift contributes to the formation of clots that obstruct small vessels, choking off blood supply to tissues and organs. Clots driven by sepsis-associated inflammation can, in severe cases, contribute to stroke and other vascular events, making it urgent to understand precisely how infection translates into thrombosis at the molecular level.

Mensah’s team will focus on a structure that has attracted growing attention in vascular biology: the glycocalyx, a delicate, gel-like coating that decorates the surface of healthy endothelial cells. Composed of membrane-bound proteins, sugar chains, and associated molecules, the glycocalyx acts as both a physical and biochemical buffer between the blood and the vessel wall. It helps repel circulating cells, moderates the passage of molecules, and presents a non-thrombogenic face to the bloodstream. During systemic infection, inflammatory mediators and enzymes can strip away or degrade this protective layer, exposing the underlying cell surface and altering the way the vessel interacts with blood components. A central aim of the WPI project is to define the molecular mechanisms responsible for this degradation, work that could reveal exactly how sepsis dismantles one of the vasculature’s key defenses.

The second major thread of the project concerns a protein with a pivotal role in normal hemostasis: von Willebrand factor. In healthy vessels, von Willebrand factor is tethered to the endothelial surface, anchored by components of the glycocalyx and associated binding partners that the Mensah laboratory intends to identify. Under inflammatory conditions, the protein detaches from the vessel wall and enters the circulating blood, where it can act as a recruitment platform for platelets, the small cellular fragments that aggregate to form clots. By charting which molecular tethers normally hold von Willebrand factor in place, and what happens to those anchors during infection, the researchers hope to explain how a system built to stop bleeding is subverted into one that promotes vessel-blocking clots.

The third objective is perhaps the most clinically ambitious: determining whether a damaged glycocalyx barrier can be rescued. If the protective coating can be restored or stabilized in the wake of sepsis-induced injury, the finding could point toward entirely new treatment strategies aimed not at dissolving clots after they form, but at preventing the vessel lining from becoming pro-thrombotic in the first place. Such an approach would represent a meaningful shift in thinking about sepsis care, where current interventions focus on controlling infection and supporting failing organs. Mensah and his student researchers will test whether the degradation process can be interrupted or reversed, a step the team describes as potentially paving the way for future sepsis therapies.

The project draws on Mensah’s broader research program, which examines the role of the glycocalyx in heart and lung disease. His work sits at the intersection of vascular biology and biomedical engineering, and his career reflects an unusually broad portfolio. He is a fellow of the American Heart Association and has previously devoted effort to the development of low-cost medical devices intended to expand healthcare access in low- and middle-income countries. That combination of fundamental mechanistic inquiry and practical, globally minded engineering shapes the ethos of the new grant, which treats rigorous laboratory training and meaningful mentorship as inseparable from the scientific questions themselves.

Mensah’s commitment to mentoring is rooted in his own trajectory. As a first-generation student from Africa, he credits mentors with guiding him through the preparation for doctoral studies and shaping his development as a researcher. He has said that he wants to pay those experiences forward by mentoring students and offering them genuine opportunities to conduct research. The NIH award operationalizes that commitment on a concrete scale: Mensah expects it will provide research opportunities to twelve WPI undergraduates. Those students will participate in course-related research projects, individual research work, and Major Qualifying Projects, the capstone experiences that every WPI undergraduate must complete in order to graduate. Embedding the sepsis research within this required structure means the work will reach students across the curriculum rather than remaining confined to a single laboratory cohort.

The Academic Research Enhancement Award program under which the grant is issued has a specific mission: supporting research training for undergraduate students at institutions, with the explicit goal of building research capacity while exposing students to the realities of scientific investigation. The WPI project is one of several new initiatives at the university funded through this program. For the students involved, the experience promises more than technical skill; it offers immersion in the full arc of a research problem, from reading the literature and formulating hypotheses to designing experiments, interpreting molecular data, and communicating findings. For the field, it represents an investment in the next generation of biomedical engineers at precisely the moment when questions about inflammation, coagulation, and vascular injury are becoming increasingly central to human health.

Mensah frames the dual purpose of the award in straightforward terms. The projects supported by the NIH, he notes, provide excellent training for students while also advancing fundamental understanding of human health. The work, he says, will establish an educational pipeline at WPI, enabling the university to train students in biology and prepare the next generation of biomedical engineers. If the laboratory succeeds on both fronts, the outcome will be twofold: a clearer molecular picture of how sepsis converts inflamed vessels into clot-forming surfaces, and a cohort of undergraduates who have already contributed to that discovery before beginning their professional careers. In a disease process as complex and deadly as sepsis-associated coagulation, progress on either front would be significant; progress on both, from a single laboratory, illustrates the model of research-integrated education that the grant is designed to support.

Subject of Research: NIH-funded undergraduate research into the molecular mechanisms linking sepsis-induced inflammation to blood clotting through glycocalyx degradation and von Willebrand factor release.

Article Title: Federal funding supports Worcester Polytechnic Institute student research into blood clots triggered by sepsis

Article References: Federal funding supports Worcester Polytechnic Institute student research into blood clots triggered by sepsis. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: sepsis, blood clots, glycocalyx, von Willebrand factor, endothelial cells, Worcester Polytechnic Institute, NIH grant, undergraduate research, biomedical engineering, inflammation, stroke, Solomon Mensah

The research, published in The Journal of Antibiotics, focused on CSA-13, the prototype of a family of laboratory-designed molecules called ceragenins. Unlike antimicrobial peptides, which are short chains of amino acids that the innate immune system deploys against invading pathogens, ceragenins are small sterol-based compounds built to reproduce the membrane-disrupting activity of those peptides without the fragility that limits their clinical use. Natural peptides are easily degraded by proteases and can be inactivated by DNA and actin released from dying tissue, conditions abundant in infected lungs. Ceragenins were engineered to sidestep those weaknesses while retaining a positively charged surface that binds to and permeabilizes bacterial membranes, and to additionally modulate inflammatory signaling through pathways involving innate immune receptors.

To test whether CSA-13 could protect the kidneys during pneumonia-induced sepsis, the team, led by Ugur Aksu of Istanbul University together with colleagues at several Turkish institutions and Paul B. Savage of Brigham Young University, worked with female C57/BL6 mice randomly assigned to four experimental groups of six animals each. One group served as a healthy control, while a second was subjected to Pseudomonas pneumonia-induced sepsis and left untreated. The remaining two groups received sepsis induction followed by either a low or a high dose of CSA-13 delivered intraperitoneally, a route that allowed the compound to circulate systemically after the infection had taken hold. The design deliberately modeled a treatment scenario rather than prophylaxis, asking whether the ceragenin could intervene after septic injury had already begun.

The investigators then tracked three interlocking dimensions of sepsis-related renal damage. Renal injury was quantified using plasma cystatin C, a small protein widely regarded as a more sensitive and reliable marker of glomerular filtration than traditional creatinine measurements because it is produced at a constant rate and is not confounded by muscle mass in the same way. Inflammation was assessed by measuring interleukin-6 concentrations in kidney tissue, since IL-6 is a central cytokine amplifier of the septic response and elevated tissue levels correlate with worse outcomes in acute kidney injury. Finally, glycocalyx integrity was evaluated through plasma hyaluronan, a glycosaminoglycan that is shed into the bloodstream when the endothelial glycocalyx—a delicate gel-like layer coating the interior surface of blood vessels—is degraded during systemic inflammation.

The glycocalyx deserves particular attention because it has emerged in recent years as both a diagnostic window and a therapeutic target in sepsis. This carbohydrate-rich coating on endothelial cells acts as a barrier that regulates vascular permeability, limits inappropriate adhesion of leukocytes, and maintains the selective sieving properties of the glomerular filtration barrier in the kidney. During sepsis, enzymes and inflammatory mediators shred the glycocalyx, releasing fragments such as hyaluronan into the circulation and simultaneously leaving the vasculature leaky and prothrombotic. In the kidney, this shedding contributes to the breakdown of filtration barriers that defines acute kidney injury. A therapy that preserves or restores the glycocalyx could therefore interrupt a critical step in the cascade from infection to organ failure, which is precisely what the researchers hoped CSA-13 might achieve.

The results were striking in two of the three domains. Both the low and high doses of CSA-13 successfully restored plasma cystatin C toward normal levels, indicating that kidney function was substantially preserved despite the septic insult. Equally important, tissue levels of interleukin-6, which surged in untreated septic mice, fell back to values indistinguishable from those of healthy controls in animals receiving either dose of the ceragenin. This dual effect—preserving filtration capacity while suppressing a key inflammatory cytokine within the kidney itself—suggests that CSA-13 acts not merely as an antibiotic reducing bacterial load but also as an immunomodulatory agent dampening the local renal inflammatory response that drives tissue damage.

Histological examination reinforced the biochemical findings. Under the microscope, the kidneys of untreated septic mice displayed the expected hallmarks of acute injury, including disruption of cellular architecture and tissue disorganization. In contrast, mice treated with either dose of CSA-13 largely maintained cellular integrity, with renal tissue structure closely resembling that of the healthy control group. The consistency of the protection across both low and high dosing regimens is noteworthy from a translational standpoint, because it hints that effective renoprotection does not require aggressive dosing, a potentially valuable property given that dose-dependent toxicity is a persistent concern with many antimicrobial agents used in critically ill patients.

The one measure that resisted the treatment was glycocalyx degradation. Plasma hyaluronan, the surrogate marker of glycocalyx shedding, remained elevated in septic mice whether or not they received CSA-13, at either dose. The authors’ conclusion was measured: the administration of the ceragenin did not substantially alter hyaluronan levels in infected animals. This finding matters because it delineates the boundary of the compound’s protective reach. CSA-13 appears to safeguard kidney function and cellular structure primarily through antimicrobial and anti-inflammatory mechanisms rather than by directly preserving the endothelial glycocalyx. In practical terms, other therapeutic strategies may still be needed alongside ceragenin therapy to address the vascular barrier failure that accompanies sepsis, and future studies will need to determine whether the persistent hyaluronan elevation reflects ongoing glycocalyx damage that is functionally compensated by other protective effects.

Even with that limitation, the study carries significant implications at a moment when antimicrobial resistance is eroding the effectiveness of the clinical arsenal against Pseudomonas aeruginosa, a notoriously drug-resistant Gram-negative pathogen and a leading cause of hospital-acquired and ventilator-associated pneumonia. Previous work has demonstrated that ceragenins retain activity against multidrug-resistant clinical isolates, function in challenging biological environments such as cystic fibrosis sputum, and show promise in animal models of peritoneal, urinary tract, and intestinal infection, as well as in early clinical studies of ceragenin-coated endotracheal tubes designed to prevent ventilator-associated pneumonia. The present findings extend this evidence base by demonstrating systemic renoprotective and anti-inflammatory effects in the septic context, raising the possibility that ceragenins could one day serve as combination agents that simultaneously control infection and prevent downstream organ damage.

The researchers conclude that intraperitoneal CSA-13 administration decreases renal interleukin-6 levels and protects both kidney function and cellular integrity in pneumonia-induced sepsis, positioning the compound as a candidate component of treatment protocols aimed at preventing acute kidney injury in this setting. Much work remains before such a protocol could reach patients: the current study involved small groups of animals, a single time course, and a single sepsis model, and questions of optimal dosing, timing, safety, and efficacy relative to standard antibiotics are unresolved. Moreover, the authors acknowledge funding support from N8 Medical, Inc., a company with commercial interest in ceragenin technology, and one coauthor serves as a paid consultant, considerations that will warrant scrutiny as the work moves toward independent replication. Nevertheless, the convergence of preserved filtration markers, normalized inflammatory cytokines, and protected tissue architecture paints a coherent and encouraging picture. If subsequent studies confirm these results, ceragenins may carve out a distinctive niche in critical care medicine—molecules conceived as peptide mimics but proving their worth as protectors of the organs that sepsis strikes hardest.

The choice of cystatin C as the primary renal endpoint reflects a broader shift in nephrology toward biomarkers that detect injury earlier than creatinine. Because cystatin C is freely filtered and reabsorbed by proximal tubular cells, rising plasma concentrations can signal declining filtration before conventional tests change, making it particularly valuable in dynamic conditions such as sepsis where hours matter for intervention.

Interleukin-6 likewise carries clinical weight beyond the laboratory. Circulating IL-6 has been associated with progression to severe sepsis and mortality in critically ill patients, and the cytokine drives endothelial activation, capillary leak, and recruitment of inflammatory cells into renal tissue. The observation that kidney tissue IL-6 normalized with treatment, rather than merely declining, suggests the compound interrupted the local amplification loop rather than blunting it partially.

The persistence of elevated hyaluronan despite preserved kidney structure also raises mechanistic questions. Glycocalyx shedding is mediated by enzymes such as heparanase and hyaluronidase activated during inflammation, and their activity may outlast the cytokine surge. Alternatively, hyaluronan released from injured pulmonary tissue could contribute to circulating levels independently of renal vascular damage, a possibility that would reconcile normal histology with unchanged biomarker values.

For Pseudomonas aeruginosa specifically, the findings arrive as the pathogen appears on global watchlists of critical-priority drug-resistant bacteria. Compounds with dual antimicrobial and immunomodulatory activity could reduce reliance on high-dose beta-lactams and aminoglycosides, agents whose nephrotoxicity compounds septic renal injury. Whether ceragenins can deliver that benefit in humans will depend on pharmacokinetic studies and larger, independent animal work before clinical trials become realistic.

Subject of Research: Evaluation of the ceragenin CSA-13 for renoprotection, anti-inflammatory effects, and glycocalyx preservation in a murine model of Pseudomonas pneumonia-induced sepsis.

Article Title: CSA-13 treatment in a murine model of Pseudomonas pneumonia-induced sepsis and its effects on renal injury, inflammation, and glycocalyx derangement

Article References: Aksu, U., Bozkurt-Guzel, C., Erkose-Genc, G., Tok, O. E., Esrefoglu, M., Oyardi, O., & Savage, P. B. (2026). CSA-13 treatment in a murine model of Pseudomonas pneumonia-induced sepsis and its effects on renal injury, inflammation, and glycocalyx derangement. The Journal of Antibiotics. https://doi.org/10.1038/s41429-026-00957-5

Image Credits: AI Generated

DOI: 10.1038/s41429-026-00957-5

Keywords: ceragenin, CSA-13, sepsis, acute kidney injury, Pseudomonas aeruginosa, pneumonia, interleukin-6, cystatin C, glycocalyx, hyaluronan, antimicrobial peptides, renal inflammation