Search Results (147)

Background: Giant cell arteritis (GCA) is a vasculitis mostly affecting older people. Primary membranous nephropathy (MN) is an immune-mediated glomerulopathy recently shown to be caused by autoantibodies. We report a case of both illnesses in an older gentleman. Case Presentation: A 63-year-old man developed systemic inflammatory signs and symptoms and near simultaneous nephrotic-range proteinuria. Investigations demonstrated both giant cell arteritis (GCA) and membranous nephropathy, with the presence of the M-type phospholipase A2 receptor (PLA2R) within subepithelial immune deposits. Renal function remained normal throughout the course. The patient achieved complete clinical and biochemical remission of both illnesses coincident with corticosteroid therapy. Conclusions: Although rare cases of concurrent GCA and MN have been reported, GCA occurring with PLA2R-positive MN has not been documented. This case raises the possibility of overlapping immunological pathways and may offer clues to the pathogenesis of GCA. Full article

Obesity is an increasingly important and modifiable driver of chronic kidney disease (CKD), with effects that extend well beyond its associations with type 2 diabetes, hypertension, and dyslipidemia. To synthesize the evidence that excess adiposity is a causal and modifiable determinant of kidney disease, and to examine how specific adipose depots injure the glomerulus and the tubulointerstitium, and then map these mechanisms onto established and emerging therapies. Throughout, obesity-related kidney disease (ORKD) denotes the full spectrum of diposity-driven renal injury, whereas obesity-related glomerulopathy (ORG) is reserved for the biopsy-defined glomerular lesion. Central, visceral, perirenal and renal-sinus adiposity act first through structural and haemodynamic mechanisms, promoting glomerular hyperfiltration, mechanical renal compression and activation of the adipose-derived renin–angiotensin–aldosterone system (RAAS). In parallel, these depots drive cellular and metabolic injury through lipotoxicity, adipokine imbalance, sterile inflammation, oxidative stress, gut dysbiosis, mitochondrial dysfunction, epigenetic remodelling and cellular senescence. Ectopic lipid accumulation within the renal parenchyma—fatty kidney—offers a unifying description of these changes and is most marked in type 2 diabetes mellitus. These interacting processes converge on podocyte stress, tubular metabolic failure, endothelial dysfunction and interstitial fibrosis, producing a phenotypic continuum that ranges from early albuminuria to obesity-related glomerulopathy and progressive CKD. Within the RAAS limb we highlight two comparatively underappreciated, adiposity-linked routes to injury: adipocyte-derived leptin directly upregulates adrenal aldosterone synthase (CYP11B2), and mast-cell chymase generates angiotensin II independently of angiotensin-converting enzyme, together reinforcing aldosterone- and angiotensin II–mediated damage that conventional RAAS blockade only partially interrupts. We further consider the counter-regulatory ghrelin–leptin axis, in which the suppression of ghrelin that accompanies obesity may withdraw an antioxidant, anti-inflammatory and podocyte-protective signal precisely as leptin-driven glomerular injury intensifies, positioning ghrelin as a plausible modulator and candidate biomarker of obesity-related kidney injury. We also examine how obesity complicates renal risk assessment, drug dosing, dialysis delivery and transplant access. Emerging, mechanism-matched therapies—SGLT2 inhibitors, GLP-1 receptor agonists, finerenone, structured lifestyle intervention, metabolic-bariatric surgery and, most recently, aldosterone synthase inhibitors that suppress the chymase- and leptin-driven aldosterone escaping receptor blockade—now enable a precision cardiovascular-kidney-metabolic framework that aligns adipose-depot biology, biomarkers, histology and treatment response to guide mechanism-based care in ORKD. Full article

Both SARS-CoV-2 infection and COVID-19 vaccination have been associated with renal complications. In the context of SARS-CoV-2 infection, kidney injury is primarily attributed to a complex interplay of systemic immune dysregulation and vascular damage. Severe infection triggers a cytokine-mediated inflammatory response characterized by elevated levels of pro-inflammatory mediators, resulting in systemic hemodynamic instability, increased capillary permeability, and renal hypoperfusion, ultimately leading to acute tubular injury. In addition, virus-induced endothelial activation promotes a prothrombotic state, microvascular injury, and further impairment of renal perfusion. Collectively, these processes converge to produce acute kidney injury (AKI) and, in severe or prolonged cases, may contribute to chronic tubulointerstitial damage and progressive renal dysfunction. In contrast, renal manifestations following COVID-19 vaccination are relatively uncommon and are thought to arise primarily from immune-mediated dysregulation rather than direct cytopathic effects. Reported cases include minimal change disease, IgA nephropathy, focal segmental glomerulosclerosis (FSGS), acute interstitial nephritis and other glomerulopathies, which present as either new-onset disease or relapses. These lesions are thought to result from transient immune activation following vaccination, including T-cell stimulation and altered humoral responses, which may trigger or unmask an underlying susceptibility to renal injury. Careful post-vaccination monitoring in high-risk populations may be warranted, and further molecular and population-level studies are needed to elucidate the underlying mechanisms and refine risk assessment. Full article

C3 glomerulopathy (C3G) and immune complex-mediated membranoproliferative glomerulonephritis (IC-MPGN) are severe complement-mediated kidney diseases. In a substantial proportion of these patients, C3 nephritic factors (C3NeFs) are detected; these autoantibodies stabilize the complement alternative pathway (AP) C3 convertase. Previous studies have investigated and distinguished properdin-dependent and properdin-independent C3NeFs. In this study, we investigated a distinct subset of C3NeFs that are exclusively active in the absence of properdin: properdin-inhibited C3NeFs. A two-step hemolytic AP convertase activity assay was employed to examine convertase activity in patient serum in the presence versus absence of properdin using the properdin inhibitor Salp20. In 7/16 patients and 1/23 healthy controls, who showed no convertase stabilization in full serum, convertase stabilization was observed upon properdin inhibition, indicating properdin-inhibited C3NeF activity. Consistent findings were obtained when purified patient Igs were added to properdin-depleted serum. Moreover, in an ELISA-based C3bBb binding assay, 6/7 patients with properdin-inhibited C3NeFs showed increased convertase binding, which decreased upon addition of properdin. Complement levels in patients with properdin-inhibited C3NeFs were not significantly different from those in the C3NeF-negative group, and properdin levels were generally within the refence range. In conclusion, our results support the existence of properdin-inhibited C3NeFs, thereby further expanding the functional heterogeneity of these autoantibodies. Although their functional relevance under physiological conditions remains unclear, these findings may have important implications for complement-targeted therapies, particularly strategies aimed at properdin inhibition, as the presence of these C3NeFs may predispose to unintended effects. Full article

Background/Objectives: Fibronectin glomerulopathy (FNG) is a rare autosomal dominant inherited kidney disease. Approximately 40% of genetically confirmed FNG cases are associated with likely pathogenic variants in FN1. Patients with FNG have similar clinical features as those with chronic nephritis. Due to nonspecific clinical manifestations mimicking common childhood glomerular diseases, FNG poses significant diagnostic challenges in children, frequently resulting in delayed diagnosis. Case Description: A 9-year-old Chinese girl presented with manifestations suggestive of acute poststreptococcal glomerulonephritis (APSGN), including edema, hypertension, hypocomplementemia, nephrotic-range proteinuria (3.34 g/24 h), and microscopic hematuria (45–55 cells/HP). Despite resolution of edema and normalized complement C3 after initial therapy, proteinuria and hematuria persisted. Renal biopsy revealed prominent mesangial deposits extending to glomerular capillary walls, with strong fibronectin (FN) immunoreactivity and fibrillary electrondense deposits on electron microscopy. Genetic testing identified a heterozygous FN1 missense variant c.3051G>C (p.Trp1017Cys) in the proband and her asymptomatic father, classified as likely pathogenic per ACMG guidelines (supporting evidence: PS1, PM2, PP3, PP4). mRNA and cDNA sequencing confirmed the transcription of the mutant allele in the family members. Notably, these transcriptional analyses cannot provide direct evidence for the functional pathogenicity of the variant. The patient received combined angiotensin-converting enzyme inhibitor (ACEI) and angiotensin receptor blocker (ARB) therapy, and renal function remained stable during 3 years of follow-up. Conclusions: The FN1 c.3051G>C represents a novel nucleotide variant, while the corresponding amino acid alteration p.Trp1017Cys has been reported in the previous literature. This case expands the variant spectrum of FN1 and emphasizes the critical value of renal biopsy and genetic testing for diagnosing FNG in pediatric patients with persistent renal manifestations after suspected APSGN. Family screening is essential for identifying asymptomatic carriers. Our findings also highlight the phenotypic heterogeneity of FNG. Full article

Oxidative stress and inflammation are key drivers of kidney injury and disease progression. In this context, the role of sialic acids emerged as a critical regulatory layer linking redox imbalance, immune activation, and tissue damage. Sialic acids are terminal negatively charged residues that regulate complement activity, immune cell signaling, and the structural integrity of the glomerular filtration barrier. Alterations in sialylation, resulting from impaired biosynthesis or increased sialidase activity, disrupt immune homeostasis, enhance inflammatory responses, and promote complement-mediated injury. In the kidney, these mechanisms contribute to podocyte dysfunction, glomerular inflammation, and fibrosis and are implicated in glomerulopathies, transplantation, and plasma cell dyscrasias. Emerging evidence also highlights the therapeutic potential of targeting sialic acid metabolism through inhibition of desialylation or restoration of sialylation pathways. Overall, sialic acids represent dynamic modulators at the intersection of oxidative stress and immunity, offering novel opportunities for biomarker development and mechanism-based therapies in kidney disease. Full article

Background: Podocyte injury leads to the shedding of podocyte-derived molecules into the urine, which may serve as biomarkers of kidney disease. These molecules could be useful for the early detection of glomerular damage and for monitoring the progression of chronic kidney disease (CKD). Methods: A prospective cohort study was conducted in pediatric patients with CKD stages 1–4 treated at a tertiary care hospital between October 2019 and January 2023. Urinary podocalyxin and creatinine were measured at baseline. Renal function was assessed at baseline and at 12 and 24 months of follow-up. Patients were stratified by CKD stage. Changes in glomerular filtration rate (ΔGFR) were calculated, and correlations with baseline podocalyxin were evaluated using Spearman’s test. Multiple linear regression was used to adjust for confounders. Results: A total of 169 patients were included (median age 11 years). Glomerulopathies were the most frequent etiology (40.8%), and stage 1 was the most prevalent. At 12 months, stage 4 CKD patients showed a positive correlation with ΔGFR (r = 0.709, p = 0.003) and a negative correlation with proteinuria (r = −0.864, p < 0.001). At 24 months, a positive correlation was observed with ΔGFR (r = 0.949, p < 0.001), while an inverse association was observed with GFR. Associations varied according to CKD etiology. Conclusions: The podocalyxin-to-creatinine ratio was positively associated with renal function and negatively with proteinuria in stage 4 CKD, but showed no utility in stages 1–3. Full article

The complement system is the primary defense mechanism against pathogens, acting through opsonization, the membrane attack complex, and classical, lectin, or alternative pathways. These pathways result in the production of key complement components, including C3a (complement component), C5a, and C3b, which recruit inflammatory cells. Complement dysregulation leads to renal disease through the overproduction of anaphylatoxins or inappropriate formation of the membrane attack complex. The levels of complement components have been shown to be useful as predictive markers in acute kidney injury, especially in conditions of alternative pathway activation, and in diseases of immune complex pathology such as lupus nephritis and IgA nephropathy. Genetic defects in complement regulatory proteins result in diseases such as C3 glomerulopathy or atypical hemolytic uremic syndrome, in which uncontrolled C3 convertase activity results in renal failure. Therapeutic interventions targeting complement components, including eculizumab or pegcetacoplan, improve patient outcomes in atypical hemolytic uremic syndrome and C3 glomerulopathy, respectively, while other interventions improve renal function in IgA nephropathy. These findings underscore the dual role of the complement system, which is not only implicated in the progression of renal diseases but also provides the potential for the development of therapeutic interventions for the treatment of various forms of nephropathy. Full article

The discovery of apolipoprotein L1 (APOL1) risk polymorphisms has significantly changed our knowledge of kidney disease susceptibility and development in African American populations. Several non-diabetic kidney disorders, such as focal segmental glomerulosclerosis (FSGS), collapsing glomerulopathy, HIV-associated nephropathy (HIVAN), and accelerated chronic kidney disease (CKD) development, are significantly more likely to occur in people with two coding variations, G1 and G2. The significance of context-dependent pathogenic processes is highlighted by the poor penetrance and remarkable phenotypic variety of APOL1-associated kidney disease, despite its substantial impact. This review synthesizes current knowledge of APOL1 biology through a molecular framework, emphasizing gain-of-toxic-function effects of risk variants in podocytes, dysregulated ion fluxes, mitochondrial dysfunction, impaired proteostasis, and activation of innate immune and inflammatory signaling pathways. We describe how the well-recognized “second-hit” paradigm has a biological basis, driven by strong inducibility by interferons and immunological activation, as well as strict basal regulation of APOL1 expression. Lastly, we explore future approaches to precision nephrology and highlight translational advancements, such as APOL1 gene-silencing techniques. This review provides a mechanistic roadmap for translating APOL1 biology into targeted therapeutic strategies by integrating genetics, cell biology, immunology, and systems-level approaches. Full article

According to the Global Burden of Disease 2019 analysis, there were 606,300 new cases of chronic kidney disease due to glomerulonephritis worldwide, with 17.3 million prevalent cases and 183,700 deaths More interestingly, between 1990 and 2019, the global burden of glomerulonephritis increased by 77% in incidence and 81% in prevalence, mainly due to demographic aging and population growth. Among primary glomerulopathies, IgA Nephropathy (IgAN), also known as Berger’s disease, is the most common primary glomerulopathy worldwide, with significant geographic and ethnic variation in incidence, with the highest prevalence in Europe and Asia and the lowest in Africa. Its pathogenesis reflects a complex interaction between polygenic susceptibility and environmental modifiers, mucosal immune activation, infections of the upper respiratory and gastrointestinal tracts, dietary factors, and alterations in the gut microbiome. In addition, IgAN increasingly coexists with other chronic diseases, such as hypertension and diabetes, which complicates both diagnosis and treatment in aging societies. All these observations suggest that in the coming years, the epidemiology of IgAN will gradually transform from a description of “case counts” to a predictive tool that integrates genetic, environmental, and molecular biomarker data. In this sense, epidemiology is increasingly becoming the foundation of precision nephrology—allowing not only for disease risk prediction but also for the design of effective therapeutic strategies. The conceptual shift in IgAN—from a disease defined by biopsy prevalence to one understood through integrative epidemiology—illustrates the broader transition of GN research toward biomarker-based risk stratification and precision medicine. This review focuses on IgA nephropathy as the most prevalent primary glomerulonephritis and uses it as a reference disease to illustrate broader epidemiological patterns, outcome trajectories, and methodological limitations relevant to primary glomerulonephritides. Full article

The influence of gaseous components of tobacco smoke, e-cigarettes, and air pollutants on the development of glomerulonephritis has been the subject of numerous studies in recent years. Glomerulonephritis (GN) often leads to progressive kidney damage and chronic kidney disease (CKD), which is a global health problem. Genetic and autoimmune factors have been shown to contribute to their development. Yet, increasing attention is being given to environmental and lifestyle-related risk factors. This paper summarizes how specific substances found in tobacco smoke, e-cigarette smoke, and air pollutants contribute to the development and progression of GN. Particular emphasis is placed on substances such as formaldehyde, heavy metals, and particulate matter, which have been shown to trigger oxidative stress, immune dysregulation, and endothelial dysfunction. A clear understanding of the contributions of those agents to kidney inflammation is crucial for developing preventive strategies and improving public health awareness. We also highlight gaps in current research and suggest directions for future investigation. Understanding consequences of cigarette smoking should be promoted to encourage people to reduce their exposure to cigarette smoke, which could prevent many diseases. Full article

Background/Objectives: IgA nephropathy (IgAN) is the most common primary glomerulopathy worldwide; it is characterized by a complex pathophysiology involving several inflammatory pathways. The Janus kinase/signal transducer and activator of transcription (JAK/STAT) pathway may be critical in this process. This study aimed to investigate the role of this pathway in IgAN and examine related tissue inflammatory markers. Methods: We analyzed 63 biopsy-confirmed patients with IgAN and performed immunohistochemical analysis on renal samples. A panel of antibodies targeting the JAK/STAT pathway, including JAK2, JAK3, p-STAT, STAT3, and MAPK/ERK, was used for this analysis. Six kidney tumor border samples were used as controls. Additionally, CD68 staining was used to evaluate tissue inflammation in the kidney biopsies. Results: Patients with IgAN showed a significantly higher cellular density of JAK3 staining at the glomerular level compared to controls, indicating JAK3 activation (p < 0.0002). Nevertheless, the correlation between JAK3 positivity in glomeruli and clinical parameters such as the initial and final estimated glomerular filtration rate (eGFR) and proteinuria was not statistically significant. Identical results were obtained with CD68+ macrophage counts in the glomerular compartment, which did not show any correlation with clinical parameters, while CD68+ tubulointerstitial staining demonstrated a significant correlation with both initial (p = 0.002) and final eGFRs (p = 0.0014), proteinuria (p = 0.010), and interstitial fibrosis (p < 0.001), as well as with renal disease progression (p = 0.005). Conclusions: Activation of the JAK/STAT pathway was observed in patients with IgAN relative to controls, notwithstanding the inability to assess the full pathway due to technical limitations. Macrophage CD68 staining in the tubulointerstitial area increased and was associated with clinical and laboratory parameters such as eGFR and proteinuria. Additionally, MEST-C histological parameters, such as segmental glomerulosclerosis (S0/S1), tubular atrophy/interstitial fibrosis (T0/T1/T2), and crescents (C0/C1/C2), were associated with a higher number of CD68+ cells. Full article

Both obesity and chronic kidney disease (CKD) are increasingly recognized as global epidemics. Their escalating incidence and far-reaching health implications highlight the urgent need for comprehensive prevention and management strategies. This review aims to clarify how obesity interacts with end-stage kidney disease (ESKD) and how to improve the management of obese patients receiving kidney replacement therapy. It also explores underlying mechanisms, current treatments, future directions, and ongoing controversies. By highlighting this intricate relationship, the review seeks to enhance clinical practice and promote further research toward more personalized care for this vulnerable population. Obesity is frequent in dialysis patients and creates challenges related to body composition, metabolism, and treatment. While higher body mass index (BMI) may appear to improve survival, this paradox does not offset the cardiovascular and functional risks of visceral and sarcopenic obesity. Obesity also increases post-transplant complications and can limit access to transplantation. Lifestyle changes rarely achieve lasting weight loss, whereas bariatric surgery—especially sleeve gastrectomy—can improve transplant eligibility with fewer complications. Weight-loss medications may be used before transplantation but remain insufficiently studied in ESKD. After transplantation, weight-reduction efforts should continue, with pharmacotherapy preferred over bariatric surgery. Comprehensive assessment strategies and individualized management approaches in ESKD patients are essential to optimize outcomes in this growing patient population. Full article

Weight loss is central to treating obesity-related kidney disease, yet the renal effects of a low-fat diet (LFD) versus bariatric surgery (BS) remain incompletely understood. This study compared their impact on obesity-related glomerulopathy (ORG). Twenty-eight male Wistar rats were fed a high-fat diet (HFD) for 10 weeks to induce obesity. Eight rats were sacrificed (the HFD group), eight switched to LFD for 10 weeks, and twelve underwent sleeve gastrectomy. Body weight, albuminuria, renal histology, and transcriptomic profiles were analyzed. Weight loss was modest in the LFD group (−1.6%) but substantial after BS (−13.2%), occurring 2.1 times faster. Albuminuria decreased in both interventions compared to HFD (LFD: 7228 ± 514 ng/mL; BS: 6242 ± 418 ng/mL; HFD: 10,384 ± 1168 ng/mL; p < 0.01) and correlated strongly with weight loss (R² = 0.78). The glomerular area was reduced in both groups, but only BS achieved complete histological resolution of ORG. Tubular cells in BS-treated rats showed megamitochondria and cristae disruption, while LFD induced milder alterations. Transcriptomics revealed suppression of mitochondrial maintenance genes and upregulation of oxidative stress and immunometabolic pathways. Immune-related genes upregulated in BS clustered into pro-inflammatory/chemotactic and regulatory modules. To the best of our knowledge, this is the first piece of evidence that BS fully reverses ORG, highlighting renal effects beyond weight loss alone. Full article

This article explores the multifaceted role of micro-ribonucleic acids (RNAs) (miRNAs) as critical posttranscriptional regulators in renal physiology and disease, with a focus on their emerging significance in glomerulopathies. miRNAs, small endogenous noncoding RNAs, modulate gene expression by promoting messenger RNA degradation or inhibiting translation, thereby orchestrating essential cellular processes such as proliferation, differentiation, apoptosis, and stress responses. Recent advances have revealed that aberrant miRNA expression profiles are intricately linked to the pathogenesis and progression of various renal diseases, including acute kidney injury, chronic kidney disease, alloimmune injury in solid organ transplantation and glomerulonephritis. This review summarizes the pathogenic and protective roles of miRNAs in major glomerulopathies, discusses their potential as diagnostic and prognostic biomarkers, and outlines future directions for their integration into personalized therapeutic strategies. At the moment, it is not fully established whether some of these mechanisms are the primary pathogenic driver or a secondary response. Combining miRNAs with other molecular markers may further enhance diagnostic and predictive accuracy, facilitating clinical translation, while selective targeting of specific miRNAs at different stages of disease progression could offer promising therapeutic opportunities. Full article