The heart’s lymphatic system is far more than a passive drainage network. Cardiac lymphatic vessels regulate fluid homeostasis within the beating organ and clear immune cells from the tissue, keeping inflammation in check. When these vessels fail to form properly, fluid accumulates and immune responses run unchecked — problems that matter both during development and after injury. Yet the mechanisms that tell cardiac lymphatic endothelial cells, or LECs, where to grow and how to pattern themselves have remained murky. To crack the problem, the researchers turned to the zebrafish, a transparent model organism whose heart can be imaged live and which, remarkably, can regenerate damaged heart muscle — a feat mammals largely cannot perform.

The team’s first technical advance was spatial transcriptomics performed on the zebrafish heart at the single-cell level. This approach maps gene expression patterns onto intact tissue, allowing researchers to see not just which genes are active in cardiac LECs, but where those cells sit relative to their neighbors. The analysis revealed striking heterogeneity among cardiac LECs: rather than a uniform population, the heart’s lymphatic endothelium comprises distinct subpopulations with different gene expression profiles. Among the genes highlighted by this screen, one stood out — adrenomedullin a, or adma, which is mainly expressed in the epicardium, the thin outer layer of the heart, adjacent to the cardiac lymphatic vessels.

Adrenomedullin is a peptide signaling molecule with well-known roles in vascular biology, but its function in cardiac lymphatic development had not been pinned down. Because adma is expressed in the epicardium rather than in the LECs themselves, the finding suggested a paracrine mechanism: the epicardium secretes adrenomedullin, which then acts on nearby lymphatic endothelial cells to guide their growth. To test this, the researchers generated adma mutant zebrafish and examined their cardiac lymphatics in detail.

The results were dramatic. adma mutants developed edema — fluid accumulation throughout the body — and dilated outflow tracts, the vessel structures that carry blood away from the heart. Their cardiac lymphatic vessels were mis-patterned and reduced in number. Even more tellingly, the ventricular lymphatics — the lymphatic vessels covering the heart’s main pumping chamber — were dilated, with fewer sprouts, increased expression of lyve1b, a lymphatic endothelial marker gene, and altered composition of lymphatic subpopulations. Together, these phenotypes show that adrenomedullin signaling is required for cardiac lymphatic vessels to form correctly, to sprout normally, and to maintain their proper subpopulation balance during development.

The researchers then investigated the other side of the signaling equation. ackr3a encodes a decoy receptor for adrenomedullin — a receptor that binds the peptide but, rather than transmitting a signal, sequesters it and thereby dampens adrenomedullin signaling. When the team deleted ackr3a in zebrafish, the effect was the opposite of adma loss: lymphatic sprouting increased. This opposing pattern of phenotypes reveals a push-pull mechanism. The epicardium provides adrenomedullin to promote lymphatic growth, while the decoy receptor Ackr3a restrains that growth by mopping up excess peptide. The balance between the two determines how many lymphatic sprouts form and how the vessels pattern themselves around the heart.

The study’s scope extended beyond development into regeneration. When the zebrafish heart is injured, it mounts a regenerative response in which the epicardium reactivates and epicardium-derived cells populate the wound. The researchers found that during heart regeneration, adma and ackr3a are expressed in epicardium-derived cells within the wound — the same molecular pair deployed during development is redeployed in the adult injured heart. This co-expression suggests that adrenomedullin signaling helps coordinate the lymphatic response to cardiac injury, potentially linking lymphatic vessel growth to the broader regenerative program.

Immune cell dynamics provided another clue to the pair’s function. Neutrophils, the first responders of the innate immune system, are cleared from tissues by the lymphatic system. The researchers found that neutrophil clearance is reduced in adma mutants — consistent with defective lymphatic function — but increased in ackr3a mutants, consistent with enhanced lymphatic sprouting and activity. This mirror-image pattern of immune cell clearance reinforces the idea that adrenomedullin and its decoy receptor jointly regulate not only lymphatic vessel architecture but also lymphatic vessel function, specifically the vessels’ capacity to remove immune cells from the heart.

Technically, the study demonstrates the power of combining spatial transcriptomics with genetic perturbation in a regenerative model organism. By mapping gene expression in cardiac LECs at single-cell resolution and then deleting candidate genes one by one, the team could connect specific molecular signals to specific lymphatic phenotypes — from sprout number to vessel dilation to subpopulation composition. The identification of distinct lymphatic subpopulations within the heart adds a new dimension to lymphatic biology, suggesting that cardiac LECs are specialized for different tasks and that signals like adrenomedullin help maintain the balance among these specialized states.

For the broader scientific community, the findings open several avenues. If adrenomedullin signaling promotes cardiac lymphatic growth while Ackr3a restrains it, then pharmacologically manipulating this axis — enhancing adrenomedullin signaling or blocking the decoy receptor — might stimulate lymphatic vessel formation in settings where lymphatic function is impaired, such as after cardiac injury or in lymphatic vascular diseases. Conversely, blocking the pathway might restrain excessive lymphatic growth. Because the zebrafish heart regenerates, the model provides a platform for testing whether tuning adrenomedullin signaling improves regenerative outcomes — a question the field can now pursue with the molecular targets in hand. The study, published as an open-access article in Nature Communications on 17 October 2026, was supported by the CIRM Scholar Award, the Heart Ambassadors Intramural Grant, and NIH NHLBI funding, and involved collaborators including J. Gage Crump at the University of Southern California and Young-Kwon Hong at Harvard Medical School.

Subject of Research: Adma and Ackr3a regulate cardiac lymphatic vessel formation and function during heart development and regeneration

Article Title: Adma and Ackr3a regulate cardiac lymphatic vessel formation and function during heart development and regeneration

Article References: Feng, X., Chen, H.-Y., Sun, Y., Sun, F., Yan, S., Kapuria, S., Rodriguez, R., Gamba, L., Crump, J. G., Hong, Y.-K., Poss, K. D., & Lien, C.-L. (2026). Adma and Ackr3a regulate cardiac lymphatic vessel formation and function during heart development and regeneration. Nature Communications. https://doi.org/10.1038/s41467-026-78353-8

Image Credits: AI Generated

DOI: 10.1038/s41467-026-78353-8

Keywords: Adma, Ackr3a, regulate, cardiac, lymphatic, vessel, formation, function, during, heart, development, regeneration

Several contributions challenge the assumption that CKD is a single, homogeneous entity once glomerular filtration rate and albuminuria are known. Romano and colleagues revisit Bricker’s decades-old intact nephron hypothesis, which holds that surviving nephrons compensate for lost ones by hyperfiltering, and propose a complementary hypofiltering nephron model in which structurally intact nephrons filter less because of increased preglomerular vascular resistance and hypoperfusion rather than nephron loss per se. Because current KDIGO staging relies solely on estimated GFR and albuminuria categories, the authors argue that mechanistically distinct patients are too often treated identically. They propose that renal hemodynamic markers, such as the intrarenal Doppler-derived resistive index, could help personalize management, and they claim that patients with CKD and hypofiltering residual nephrons should be treated differently than those with hyperfiltration of residual nephrons. This conceptual work is complemented by Rico-Fontalvo and colleagues, whose mini review dissects how obesity drives CKD through interlinked inflammatory and lipotoxic pathways, reinforcing that metabolic phenotype, not eGFR alone, shapes disease trajectory. The authors discuss their proposed classification of obesity-related CKD.

Pregnancy offers a further illustration of why reliance on non-pregnant laboratory norms can misclassify abnormalities and delay recognition of clinically important disturbances. Meena and Batool synthesize how systemic vasodilation, neurohormonal activation, and maternal-fetal mineral exchange reset the normal ranges for osmoregulation, sodium-water homeostasis, potassium, magnesium, and calcium across gestation. Their synthesis provides a practical framework for distinguishing physiological adaptation from pathological disturbance in this understudied area of obstetric nephrology, a distinction with direct consequences for how clinicians interpret routine blood tests in pregnant patients and decide when an abnormal value reflects genuine disease rather than expected gestational change.

Two original research articles test therapies aimed at the outcomes that matter most to patients with CKD: kidney failure and cardiovascular disease. Aledan and Abbood report a prospective cohort study of finerenone in 180 patients with CKD stages 3 to 4, with estimated GFR between 20 and 60 mL/min, including diabetic and non-diabetic participants and patients with eGFR as low as 20 mL/min, populations historically underrepresented in finerenone trials. Over one year, finerenone significantly improved eGFR and urinary albumin-to-creatinine ratio without a meaningful rise in serum potassium, extending the evidence base for this drug class to a broader, more advanced CKD population. The nonsteroidal mineralocorticoid receptor antagonist class has drawn intense attention since large outcome trials, and this real-world cohort adds weight to the argument that patients with more advanced disease can also benefit when monitoring protocols are followed.

Cardiovascular risk after transplantation is the focus of Thuy and Thang’s study of plasma asymmetric dimethylarginine, an endogenous nitric oxide synthase inhibitor, in 75 patients before and six months after kidney transplantation. ADMA fell substantially after transplant but remained more than three times higher than in healthy controls, and was independently associated with dyslipidemia, the atherogenic index of plasma, and post-transplant hemoglobin and HDL-cholesterol levels. The findings support ADMA as a candidate marker of residual cardiovascular risk even after otherwise successful transplantation, a clinically important point because cardiovascular disease remains a leading cause of death with a functioning graft, and because conventional risk scores often fail to capture the specific metabolic and inflammatory milieu of transplant recipients.

A number of papers explore how biomarkers and computational methods can enhance and sharpen diagnosis. Fu and colleagues review neutrophil gelatinase-associated lipocalin, known as NGAL, as a biomarker for both acute kidney injury and peritoneal dialysis-related peritonitis, arguing for its potential as an early, non-invasive signal across two clinically distinct but mechanistically related complications. Wu and colleagues use the electronic Intensive Care Unit Collaborative Research Database to examine the association between serum bicarbonate and 28-day in-hospital mortality in dialysis patients, adding evidence that acid-base status carries prognostic weight in critically ill patients on renal replacement therapy. Their research indicates that serum bicarbonate levels below 30 mmol/L are linked to an increased risk of death. Jiang and colleagues apply machine learning to transcriptomic data to build and validate a diagnostic model linking two chronic wasting diseases, uremia and major depressive disorder, and begin to map the shared molecular biology behind a common but under-recognized comorbidity of kidney failure. In the transplantation space, Loizeau and colleagues quantify measurement uncertainty in renal transplant biopsy assessment, a reminder that even the histopathologic gold standard for diagnosing rejection carries inter-observer variability that should inform treatment decisions.

Two contributions bring the discussion back to the patient. Shankar and Lamech catalog the treatment burden imposed by long-term immunosuppressive therapy for glomerular disease, weighing efficacy against infection risk, metabolic complications, and quality of life, financial burden, and calling for strategies judged not only by remission rates but by what patients endure to achieve them. Qi and colleagues contribute a case report of IgA nephropathy with partial crescentic lesions in a patient with brucellosis, an unusual juxtaposition that highlights how systemic infection can unmask or accelerate glomerular injury. Crescentic lesions signal aggressive inflammation within the glomeruli, and the association with a chronic bacterial infection raises questions about whether immune activation driven by the pathogen contributed to the renal lesion, a mechanism that remains speculative but clinically instructive for nephrologists evaluating patients with concurrent infection and rapidly progressive kidney disease.

Across these eleven articles, several threads recur despite the breadth of topics. The limits of GFR and albuminuria as the sole means for staging CKD emerge repeatedly, whether through the hypofiltering nephron model, the metabolic classification of obesity-related kidney disease, or the hemodynamic markers proposed to refine risk assessment. The persistence of cardiovascular risk even after kidney replacement appears both in the finerenone cohort and in the ADMA study, underscoring that restoring kidney function does not automatically restore vascular health. The value of biomarkers that anticipate injury rather than merely confirm it runs through the NGAL review, the bicarbonate mortality analysis, and the transcriptomic modeling of uremic depression, while the transplant biopsy uncertainty study adds a cautionary note about the reliability of the diagnostic gold standard itself.

The human cost of therapies used to control glomerular disease completes the picture. Immunosuppressive regimens have transformed once-fatal glomerulopathies into manageable conditions, yet the catalog of infections, metabolic complications, financial strain, and quality-of-life sacrifices documented by Shankar and Lamech argues for a broader definition of treatment success. In parallel, the obstetric nephrology synthesis and the brucellosis-associated IgA nephropathy case remind readers that kidney disease does not occur in isolation from pregnancy physiology or systemic infection, and that context-specific norms and mechanisms are essential for accurate diagnosis.

That breadth is precisely the point of a Rising Stars collection: it captures the range of questions that early-career nephrologists are choosing to ask, from nephron-level physiology to population-scale database analyses, from pharmacologic trials to bioinformatic modeling of comorbidity. The editorial’s author thanks the authors, reviewers, and editors who contributed to the Research Topic, and looks forward to seeing how these emerging investigators continue to shape the future of kidney health. For a field confronting a global epidemic of kidney disease, the message is that the pipeline of ideas, methods, and investigators is active, technically diverse, and already producing evidence that could change how CKD is staged, how cardiovascular risk is measured after transplantation, and how the burden of treatment is weighed against its benefits.

Subject of Research: Early-career nephrology research spanning CKD staging, biomarkers, transplantation, and glomerular disease

Article Title: Editorial: Rising stars in nephrology 2024: illuminating the future of kidney health

Article References: Kotanko, P. (2026). Editorial: Rising stars in nephrology 2024: illuminating the future of kidney health. Frontiers in Nephrology, 6, Article 1985175. https://doi.org/10.3389/fneph.2026.1985175

Image Credits: AI Generated

DOI: 10.3389/fneph.2026.1985175

Keywords: chronic kidney disease, nephrology, finerenone, kidney transplantation, biomarkers, NGAL, ADMA, machine learning, pregnancy, glomerular disease, dialysis, immunosuppression

Cadmium is a heavy metal with no known biological function in the human body, yet it accumulates relentlessly in tissues, particularly the kidneys, with a biological half-life measured in decades. Workers in industries involving metal smelting, battery manufacturing, welding, electroplating, and the processing of zinc and copper ores can inhale cadmium-containing fumes and dust over years of employment. While the metal’s links to kidney damage, bone disease, and cancer have been studied extensively, its effects on the endocrine system and on vascular biology in exposed workers have received comparatively little attention in human studies, a gap the new research set out to address.

The study team, led by Deniz Özkan Vardar of Lokman Hekim University in Ankara together with collaborators from several Turkish universities and occupational health institutions, enrolled 170 adult men: 85 workers with documented occupational cadmium exposure and 85 unexposed controls matched for comparison. To quantify the internal cadmium burden of each participant, the researchers measured urinary cadmium concentrations using inductively coupled plasma mass spectrometry, or ICP-MS, an analytical technique sensitive enough to detect trace metals at parts-per-billion levels. Urinary cadmium is widely regarded as the preferred biomarker of cumulative body burden because the metal accumulates in the kidneys and is slowly excreted, so urine levels reflect decades of exposure rather than recent contact alone.

Beyond the metal itself, the team assembled an unusually comprehensive panel of biomarkers spanning two physiological domains. On the endocrine side, they measured serum total testosterone along with luteinizing hormone and follicle-stimulating hormone, the two pituitary hormones that regulate the testes through the hypothalamic-pituitary-gonadal axis. On the vascular side, they quantified asymmetric dimethylarginine and symmetric dimethylarginine, known as ADMA and SDMA, together with their precursor arginine and related metabolite citrulline. ADMA is of particular interest to cardiovascular researchers because it inhibits endothelial nitric oxide synthase, the enzyme that produces nitric oxide, the signaling molecule responsible for relaxing blood vessels and maintaining vascular health. Elevated ADMA is considered a harbinger of endothelial dysfunction and cardiovascular risk.

The results were striking in their consistency. Cadmium-exposed workers had substantially higher urinary cadmium concentrations than the unexposed controls, confirming that their occupational environment translated into a measurably greater internal body burden. More importantly, the exposed group showed significantly higher serum levels of both ADMA and SDMA, with differences that reached the stringent threshold of p less than 0.001. At the same time, total testosterone, follicle-stimulating hormone, and the arginine-to-ADMA ratio were all significantly lower in the exposed workers, while luteinizing hormone showed a smaller but still statistically significant reduction. The arginine-to-ADMA ratio is a meaningful composite index, because it reflects the balance between the substrate available for nitric oxide production and the endogenous inhibitor that blocks it; a falling ratio suggests a shift toward suppressed nitric oxide bioavailability.

Perhaps most telling were the correlation analyses. Urinary cadmium concentrations were inversely correlated with total testosterone and with follicle-stimulating hormone, meaning that the greater a worker’s internal cadmium burden, the less favorable his endocrine profile tended to be. This dose-response-like relationship strengthens the biological plausibility of a causal link, although the cross-sectional design of the study, which captures a single moment in time, means that it demonstrates association rather than definitive causation. Reverse causation and confounding by other workplace exposures or lifestyle factors cannot be fully excluded, a limitation the authors acknowledge implicitly by framing their findings as a basis for combined biomarker monitoring rather than as proof of harm.

The simultaneous disruption of both endocrine and endothelial markers is what makes the study particularly noteworthy. Cadmium is known from experimental work to interfere with steroidogenesis, the enzymatic machinery inside Leydig cells that converts cholesterol into testosterone, and to damage the seminiferous tubules where sperm are produced. The observed pattern of reduced testosterone alongside reduced LH and FSH suggests that cadmium’s effects may not be confined to the testes themselves but may also involve higher levels of the hypothalamic-pituitary-gonadal axis, since primary testicular failure would typically drive these pituitary hormones upward rather than down. Disentangling whether cadmium acts at the brain, the pituitary, the testes, or all three will require longitudinal and mechanistic follow-up.

On the vascular side, the elevation of ADMA and SDMA in exposed workers fits with growing evidence that heavy metals promote cardiovascular disease in part by degrading nitric oxide signaling. Cadmium generates oxidative stress, and reactive oxygen species accelerate the enzymatic degradation of ADMA’s clearance, raising its circulating levels. Because endothelial dysfunction is an early and reversible stage of atherosclerosis, the finding raises the possibility that cadmium-exposed workers accumulate cardiovascular risk silently, years before any clinical event. The concurrent decline in the arginine-to-ADMA ratio provides a quantitative handle on this shift and suggests a potential monitoring target that could be tracked in occupational health surveillance programs.

The practical implications extend beyond the laboratory. The authors suggest that combined assessment of endocrine and endothelial biomarkers may prove useful for occupational monitoring of workers with chronic cadmium exposure, complementing the traditional reliance on urinary cadmium and kidney function measures such as estimated glomerular filtration rate. If validated in larger and longitudinal cohorts, a panel that includes testosterone, FSH, ADMA, and SDMA could allow occupational physicians to detect subclinical physiological disruption earlier, intervene with exposure controls or job rotation sooner, and ultimately protect a workforce that often has few alternatives to hazardous industrial environments. Regulatory limits on airborne cadmium exist in most industrialized countries, but enforcement varies, and the study is a reminder that even exposures within permissible ranges may leave biochemical fingerprints.

The research also arrives amid broader public concern about endocrine-disrupting chemicals and the slow, cumulative ways in which environmental toxicants shape long-term health. Cadmium does not degrade, persists in soil and tobacco smoke as well as in industrial settings, and enters the general population through food crops grown on contaminated land. For the general public, dietary exposure and smoking dominate; for industrial workers, inhalation can dwarf these routes. As analytical techniques like ICP-MS and liquid chromatography-tandem mass spectrometry make it ever cheaper and easier to measure trace toxicants and their biochemical consequences, studies of this kind are likely to multiply, building the evidence base needed to translate molecular signals into concrete workplace protections. For now, the message from Ankara is clear: the same metal that quietly damages kidneys and bones may also be quietly rewiring the hormonal and vascular chemistry of the men who work with it, and routine blood and urine tests may be able to see it coming.

Subject of Research: Occupational cadmium exposure and its association with endocrine and endothelial biomarker alterations in male workers

Article Title: Occupational cadmium exposure and endocrine biomarker alterations in male workers: a cross-sectional study

Article References: Özkan Vardar, D., Tutkun, L., İritaş, S. B., Gözükara, M. G., Abuşoğlu, G., Deniz, S., Türksoy, V. A., & Tutkun, E. (2026). Occupational cadmium exposure and endocrine biomarker alterations in male workers: a cross-sectional study. BMC Endocrine Disorders, 26(1), Article 296. https://doi.org/10.1186/s12902-026-02605-3

Image Credits: AI Generated

DOI: 10.1186/s12902-026-02605-3

Keywords: cadmium, occupational exposure, testosterone, ADMA, SDMA, FSH, LH, endocrine disruption, endothelial dysfunction, biomarkers, occupational health, toxicology