The research, led by Yingying Zhu, Chun Jiang, Xiuhui He, Xiang Gao, and corresponding author Zhengxuan Jiang of the Department of Ophthalmology at The Second Affiliated Hospital of Anhui Medical University, describes a previously underappreciated signaling chain that connects the metabolic chaos of diabetes to the physical collapse of the retinal endothelial barrier. At the heart of the discovery is histone lactylation, a relatively recently identified epigenetic mark in which lactate-derived lactyl groups are chemically attached to lysine residues on histone tails. Rather than being an inert byproduct of metabolism, lactate in this context acts as a signaling molecule that reshapes which genes are switched on inside retinal blood vessel cells.

To dissect the mechanism, the team assembled evidence from multiple complementary systems. They examined human epiretinal membranes and fibrovascular membranes obtained from patients with proliferative diabetic retinopathy, retinal tissue from diabetic rats, and retinal endothelial cells grown under diabetic-like conditions. Across all of these models, a consistent pattern emerged: where lactate accumulated, protein lactylation rose, and one particular mark—lactylation at lysine 9 of histone H3, abbreviated H3K9la—stood out as prominently elevated under diabetic conditions. This convergence across human tissue, animal models, and cultured cells gave the finding a robustness that single-model studies often lack.

The critical question was what H3K9 lactylation actually does inside these endothelial cells. Histone modifications of this kind generally work by altering the physical state of chromatin, the complex of DNA and protein that packages the genome. When specific histone residues are acetylated or lactylated, the chromatin at nearby genes tends to loosen, granting the transcriptional machinery access and boosting gene expression. The researchers found that lactate-driven H3K9la became enriched at the promoter region of the PTK2 gene, which encodes focal adhesion kinase, a well-known regulator of cell adhesion, migration, and survival. With the promoter epigenetically opened up, PTK2 transcription increased, and levels of the phosphorylated, active form of the kinase climbed in parallel.

From there, the story moves from the nucleus to the cytoskeleton. Activated PTK2 was found to associate with FMNL2, a formin-family protein that governs the assembly of actin filaments, and this association was linked to increased tyrosine phosphorylation of FMNL2 itself. The consequence was a cascade of cytoskeletal remodeling inside the endothelial cells: the internal scaffolding of the cells reorganized in a way that destabilized VE-cadherin, the adhesive molecule that stitching neighboring endothelial cells together at adherens junctions. When VE-cadherin junctions falter, the endothelial sheet loses its seals, permeability rises, and fluid and proteins leak across the barrier. In the retina, that leakage translates directly into macular edema and progressive vision impairment.

What makes this axis scientifically compelling is that it forges a direct line from metabolism to cell structure through epigenetics. Diabetic tissue is known to be lactate-rich, a product of altered glucose metabolism and hypoxic stress. The study shows that this excess lactate does not merely fuel inflammation or oxidative damage indirectly; it physically marks the chromatin of barrier-regulating genes, amplifies a kinase–formin signaling module, and dismantles the junctions that hold the retinal vasculature together. In effect, a metabolic byproduct of diabetes becomes an epigenetic instruction that tells blood vessel cells to let go of each other.

Just as importantly, the research demonstrates that the damage is not irreversible in experimental settings. The team showed that pharmacologically reducing lactate production, inhibiting the catalytic activity of CBP/p300—the histone acetyltransferase enzymes responsible for writing lactylation marks—blocking PTK2 activity, or knocking down FMNL2 all attenuated endothelial barrier defects and reduced retinal vascular leakage. Each of these interventions targets a different rung on the same ladder, and the fact that several independent points of disruption produce protective effects strengthens the causal interpretation of the pathway and opens multiple potential angles for therapy.

The therapeutic implications are considerable. Existing treatments for diabetic retinopathy, such as anti-VEGF injections and laser photocoagulation, address downstream consequences of vascular dysfunction rather than the metabolic and epigenetic drivers of barrier failure. If the lactate–H3K9la–PTK2–FMNL2 axis can be safely modulated in patients—for example, by limiting lactate accumulation, tuning histone lactylation, or inhibiting focal adhesion kinase signaling locally in the eye—clinicians might one day intervene earlier in the disease process, before irreversible vascular damage takes hold. PTK2 inhibitors already exist in oncology research, and CBP/p300 catalytic inhibitors are under active investigation in multiple fields, meaning that repurposing strategies could accelerate translation.

The study also adds to a fast-growing body of literature on lactylation as a regulatory modification. Since histone lactylation was first described as a link between cellular metabolism and gene regulation, researchers have implicated it in macrophage polarization, tumor biology, fibrosis, and neural inflammation. The new work extends this framework to the vascular endothelium of the eye, suggesting that lactylation may be a general mechanism by which metabolically stressed tissues lose barrier integrity. Given that barrier failure is central to conditions ranging from sepsis to diabetic kidney disease, the conceptual reach of these findings may extend well beyond ophthalmology.

Caveats remain, as they always do at this stage of research. The pharmacological interventions were tested in experimental and preclinical systems, and the leap from rat retinas and cultured endothelial cells to human therapy will require careful validation, dosing studies, and safety assessment. Human tissue samples from proliferative diabetic retinopathy show the molecular signature, but they represent an advanced stage of disease; whether earlier interventions along this axis prevent progression is a question for future longitudinal work. Still, the identification of a defined metabolic–epigenetic–signaling pathway underlying inner blood–retinal barrier breakdown represents a genuine conceptual advance, one that reframes diabetic retinopathy not simply as a disease of damaged vessels, but as a disease of miswritten chromatin in the cells that guard the eye.

Subject of Research: Lactate-induced H3K9 histone lactylation disrupting the inner blood–retinal barrier via the PTK2–FMNL2 axis in diabetic retinopathy

Article Title: Lactate-induced H3K9 lactylation disrupts the inner blood–retinal barrier by activating the PTK2–FMNL2 axis in diabetic retinopathy

Article References: Zhu, Y., Jiang, C., He, X., Gao, X., & Jiang, Z. (2026). Lactate-induced H3K9 lactylation disrupts the inner blood–retinal barrier by activating the PTK2–FMNL2 axis in diabetic retinopathy. Cellular and Molecular Life Sciences. https://doi.org/10.1007/s00018-026-06448-y

Image Credits: AI Generated

DOI: 10.1007/s00018-026-06448-y

Keywords: diabetic retinopathy, inner blood–retinal barrier, histone lactylation, H3K9la, lactate, PTK2, FMNL2, VE-cadherin, endothelial permeability, focal adhesion signaling, epigenetics, retinal vascular leakage

The first concern centers on who was actually included in the meta-analysis. According to the commentary, the review stated that eligible participants were individuals with type 1 or type 2 diabetes mellitus, yet studies involving people with gestational diabetes and prediabetes were subsequently included in the analysis. The corresponding PROSPERO registration record, which documents the review protocol in advance, defined the eligible population simply as subjects with diabetes mellitus, without explicitly specifying these additional groups. Fuentes-Barría argues that this drift between the registered protocol and the executed review matters because gestational diabetes and prediabetes differ substantially from established type 1 and type 2 diabetes in pathophysiology, baseline cardiovascular and metabolic risk, and clinical management. Pooling these distinct populations, he contends, inflates clinical heterogeneity and weakens the applicability of the combined estimates to any single patient group.

A second and equally consequential issue involves the nature of the interventions themselves. Not all of the trials included in the meta-analysis tested zinc alone. Some interventions combined zinc with other micronutrients or bioactive compounds, a fact the original authors themselves acknowledged when they conceded that such co-interventions make it difficult to attribute observed effects specifically to zinc. The commentary argues that mixing zinc-only trials with multicomponent interventions introduces another layer of clinical heterogeneity and complicates the interpretation of pooled effects. To resolve this ambiguity, the commentator recommends sensitivity analyses that exclude multicomponent interventions, which would reveal whether the reported benefits survive when the analysis is restricted to trials in which zinc is the sole active agent. Without such analyses, he suggests, readers cannot judge the robustness of the pooled estimates or the extent to which zinc itself deserves credit.

Statistical heterogeneity represents the third pillar of the critique. The commentary highlights that several pooled outcomes showed substantial or even considerable heterogeneity across the included trials. The most striking example is plasma zinc concentration, where the I-squared statistic reached 99 percent, meaning virtually all of the variability between studies reflects real differences rather than chance. Other metabolic and inflammatory outcomes also demonstrated high heterogeneity. Although the original authors applied random-effects models and conducted meta-regression in an attempt to account for this variability, the commentary notes that substantial residual heterogeneity remained unexplained. Under these circumstances, Fuentes-Barría argues, a single pooled estimate carries limited clinical meaning, and its generalizability to diverse patient populations, dosing regimens and treatment durations should be interpreted with pronounced caution.

The fourth concern targets the meta-regression analyses themselves. The original review performed multiple meta-regressions examining age, sex, zinc dose and intervention duration as potential effect modifiers, despite several outcomes being based on a limited number of studies. This is problematic, the commentary explains, because meta-regression generally requires an adequate number of studies per moderator variable to produce reliable results. The Cochrane Handbook, the field’s leading methodological reference, advises caution when fewer than ten studies are available for such analyses. Beyond official guidance, methodological research has shown that meta-regression analyses are frequently undermined by overfitting and other pitfalls that can generate misleading findings. A meta-epidemiological study cited in the commentary found that most published meta-regressions based on aggregate data suffer from such methodological problems. Given the limited number of trials and the multiple moderators examined, the commentator concludes that these dose-response and subgroup associations should be treated as exploratory and hypothesis-generating rather than confirmatory evidence.

Perhaps the most clinically pointed criticism concerns the gap between the review’s title and its actual findings. The meta-analysis did not demonstrate significant improvements in fasting plasma glucose or HbA1c, the two canonical measures of glycemic control, despite the title emphasizing glycemic control as a primary outcome. Instead, statistically significant effects were observed primarily for surrogate markers, including circulating insulin levels, HOMA-IR as a measure of insulin resistance, C-reactive protein as an inflammatory marker, and various oxidative stress biomarkers. The commentary argues that these statistically significant shifts in surrogate endpoints should not automatically be equated with clinically meaningful improvements in diabetes control or with outcomes that matter to patients, such as reduced complications, improved quality of life or decreased mortality. Research on surrogate endpoints in diabetes trials has repeatedly shown that changes in biomarkers do not always translate into tangible clinical benefit, making this distinction far more than a semantic quibble.

The commentary’s overall message is one of measured skepticism rather than outright rejection. Fuentes-Barría explicitly frames his remarks as a constructive contribution to a clinically relevant topic, acknowledging the importance of the question the original review addressed. Zinc is an essential trace element involved in insulin synthesis, storage and secretion, as well as in antioxidant defense mechanisms, which provides a plausible biological rationale for studying its supplementation in diabetes. However, plausibility of mechanism cannot substitute for methodological rigor in the evidence synthesis that is supposed to translate biology into clinical recommendations. The commentary suggests that the enthusiasm generated by statistically significant pooled effects on biomarkers risks outpacing what the underlying trial data can actually support.

To strengthen the evidence base, the commentator proposes a concrete path forward. Stratified and sensitivity analyses by diabetes phenotype would clarify whether zinc exerts different effects in type 1 diabetes, type 2 diabetes, gestational diabetes and prediabetes, populations whose distinct metabolic contexts could plausibly modify any treatment effect. Restricting analyses to zinc-only interventions would isolate the specific contribution of the mineral from that of co-administered compounds. And prioritizing clinically relevant glycemic outcomes, particularly HbA1c and fasting glucose, over surrogate biomarkers would anchor the conclusions in endpoints that directly inform patient care. These refinements, the commentary argues, could substantially improve both the validity and the clinical interpretability of future updates to this body of evidence.

The exchange is a timely reminder of how meta-analyses, often perceived as the pinnacle of the evidence hierarchy, remain only as reliable as the methodological choices embedded within them. Decisions about which populations to pool, which interventions to combine, how to handle heterogeneity and how many moderator analyses to run can each shift the final estimates and the confidence readers place in them. For the growing number of people with diabetes worldwide who may be considering zinc supplements, and for the clinicians who advise them, the commentary underscores that the current evidence supports caution: meaningful effects on the measures that define diabetes control have not yet been demonstrated, and the significant biomarker changes reported so far should be viewed as signals worth further investigation rather than proof of clinical benefit. As the field awaits more rigorously designed and analyzed syntheses, the debate illustrates the self-correcting nature of scientific publishing, where critical commentary serves as an essential quality-control mechanism for evidence that ultimately shapes real-world health decisions.

Subject of Research: Methodological critique of a meta-analysis on zinc supplementation in diabetes

Article Title: Comment on ‘Effects of Zinc Supplementation on Glycemic Control, Insulin Resistance, Inflammation and Oxidative Stress in Diabetes’

Article References: Fuentes‐Barría, H. (2026). Comment on ‘Effects of Zinc Supplementation on Glycemic Control, Insulin Resistance, Inflammation and Oxidative Stress in Diabetes’. Endocrinology, Diabetes & Metabolism, 9(5), Article e70328. https://doi.org/10.1002/edm2.70328

Image Credits: AI Generated

DOI: 10.1002/edm2.70328

Keywords: zinc supplementation, diabetes, meta-analysis, glycemic control, insulin resistance, HbA1c, inflammation, oxidative stress, clinical heterogeneity, meta-regression, Comment, Effects

The study, led by a team of eminent scientists including Abaj, Aali, and Najafi, explored how specific genetic markers can indicate a patient’s risk for developing cardiometabolic disorders, which include conditions such as heart disease, hypertension, and diabetes. Understanding this genetic predisposition enables healthcare professionals to tailor preventative measures effectively, aligning treatment strategies to the individual needs of patients based on their genetic makeup.

Diabetic patients, particularly those with advanced disease, often grapple with a heightened state of inflammation and oxidative stress. Inflammation serves as a biological response to harmful stimuli, such as pathogens or damaged cells, while oxidative stress arises from an imbalance between free radicals and antioxidants in the body. When these processes become chronic, they can lead to significant cellular damage, exacerbating diabetic complications and increasing mortality risks.

The findings from this research highlight the vital role of genetic predisposition in this context. By identifying specific genetic signatures associated with higher cardiometabolic risks, medical practitioners can improve early detection capabilities. This proactive approach can empower patients through lifestyle modifications, regular monitoring, and timely medical interventions, thereby potentially reversing the trajectory of their diseases.

In the study, participants provided blood samples that were analyzed for both genetic markers and various biomarkers indicative of inflammation and oxidative stress. The results revealed a complex interplay between these markers, suggesting that individuals with certain genetic profiles exhibited elevated levels of inflammatory and oxidative stress indicators. This discovery paves the way for further inquiries into how these genetic factors may entirely dictate individual responses to inflammation and oxidative stress in diabetic populations.

Moreover, the research holds implications for personalized medicine—an evolving field that emphasizes customization of healthcare based on individual patient characteristics. The identification of specific genetic signatures as potential precursors to cardiometabolic risks could lead to more personalized treatment plans that extend beyond standard care protocols, resulting in improved management and outcomes for those with diabetes.

While the results are promising, researchers caution that additional studies are warranted to refine these genetic markers’ understanding and establish definitive causal relationships. More expansive and diverse participant cohorts will enhance the generalizability of the findings, ensuring that conclusions drawn apply not just to specific populations but to broader segments of the diabetes-affected community.

The medical community’s responsiveness to these findings could revolutionize diabetes care. Physicians may be prompted to reassess traditional risk factors in the context of genetic predisposition, leading to a paradigm shift in how diabetes is managed. Instead of only focusing on lifestyle factors such as diet and exercise, there may be increased emphasis on genetic testing and analysis as vital components of patient evaluation.

Furthermore, the potential for developing novel therapeutic interventions targeting specific genetic profiles opens exciting avenues in diabetes treatment. For instance, therapies designed to alleviate the effects of oxidative stress may prove more effective in individuals identified as high-risk through genetic testing, ultimately leading to tailored pharmacological strategies that enhance patient quality of life and longevity.

As research progresses, collaboration among geneticists, endocrinologists, and primary care providers will be essential for translating these findings into practice. Shared knowledge and resources can facilitate the rapid deployment of genetic screening techniques in clinical settings, enabling healthcare professionals to identify at-risk patients swiftly and provide targeted interventions.

In summary, this study marks a significant advancement in our understanding of diabetes and its related cardiometabolic risks. By establishing a definitive link between genetic factors and biomarkers of inflammatory and oxidative stress, researchers have opened a new frontier in personalized medicine. With ongoing investigation and the potential for clinical application, the future of diabetes care looks promising, heralding a shift towards more individualized, effective treatment strategies that prioritize patient-specific needs and genetic profiles.

The impact of these findings extends beyond individual health, promising broader public health benefits by potentially reducing the burden of diabetes-related complications on healthcare systems globally. As we demystify the genetic underpinnings of diabetes and its associated risks, we are likely to witness a transformation in how we approach prevention, diagnosis, and treatment in the realm of chronic diseases.

This research exemplifies the remarkable advancements being made in the fields of genetics and metabolic disorders. As scientists continue to peel back the layers of complexity surrounding diabetes, the hope exists that insights gleaned from such studies will ultimately pave the way for breakthroughs that significantly enhance patient care and health outcomes.

In conclusion, the future of diabetic care demands a concerted effort toward understanding the genetic influences on disease progression. It is through such exploration that we can fully realize the promise of personalized medicine, ensuring that individuals receive the most precise and effective care tailored to their unique genetic backgrounds.

Subject of Research: The relationship of genetic signatures for cardiometabolic risk with biomarkers of inflammatory and oxidative stress in diabetic patients.

Article Title: The relationship of genetic signature for cardiometabolic risk with biomarkers of inflammatory and oxidative stress in diabetic patients.

Article References:

Abaj, F., Aali, Y., Najafi, F. et al. The relationship of genetic signature for cardiometabolic risk with biomarkers of inflammatory and oxidative stress in diabetic patients.
BMC Endocr Disord 25, 148 (2025). https://doi.org/10.1186/s12902-025-01973-6

Image Credits: AI Generated

DOI:

Keywords: Genetic signatures, cardiometabolic risk, biomarkers, inflammatory stress, oxidative stress, diabetes, personalized medicine.