Collagenofibrotic glomerulopathy

Simultaneous Occurrence of Collagen Type III Glomerulopathy and Immunoglobulin A Nephropathy: A Rare Case Report

BACKGROUND Collagen type III glomerulopathy (CG) is a rare disease with poorly understood pathogenesis, usually identified by abnormal collagen type III accumulation in glomeruli and manifesting as progressive deterioration of kidney function with nephrotic-range proteinuria. Immunoglobulin A nephropathy (IgAN) is the most prevalent glomerulopathy worldwide and is a leading cause of end-stage renal disease as a result of progressive fibrotic changes. Fibrosis is primarily caused by collagen type III deposition, which may explain the simultaneous occurrence of IgAN and CG. CASE REPORT A young man presented with clinical and laboratory evidence of chronic kidney injury, including long-term nephrotic-range proteinuria and microscopic hematuria. Partial improvement in proteinuria was achieved with steroid therapy and conservative management. As the non-invasive workup was inconclusive, and a complete recovery of kidney function was not achieved, a kidney biopsy was done. Histopathological microscopic examination revealed advanced IgA nephropathy, Oxford classification M0E1S1T2C0, with features highly suggestive of type III collagen glomerulopathy. CONCLUSIONS We described a case of collagen type III glomerulopathy, also known as collagenofibrotic glomerulopathy, and its association with concurrent immunoglobulin A nephropathy in a healthy man presenting with chronic proteinuria and microscopic hematuria. As the number of reported cases in the Middle East is rising, we present this report to improve understanding and greater recognition of such cases.

Biochemical composition of the glomerular extracellular matrix in patients with diabetic kidney disease

In the glomeruli, mesangial cells produce mesangial matrix while podocytes wrap glomerular capillaries with cellular extensions named foot processes and tether the glomerular basement membrane (GBM). The turnover of the mature GBM and the ability of adult podocytes to repair injured GBM are unclear. The actin cytoskeleton is a major cytoplasmic component of podocyte foot processes and links the cell to the GBM. Predominant components of the normal glomerular extracellular matrix (ECM) include glycosaminoglycans, proteoglycans, laminins, fibronectin-1, and several types of collagen. In patients with diabetes, multiorgan composition of extracellular tissues is anomalous, including the kidney, so that the constitution and arrangement of glomerular ECM is profoundly altered. In patients with diabetic kidney disease (DKD), the global quantity of glomerular ECM is increased. The level of sulfated proteoglycans is reduced while hyaluronic acid is augmented, compared to control subjects. The concentration of mesangial fibronectin-1 varies depending on the stage of DKD. Mesangial type III collagen is abundant in patients with DKD, unlike normal kidneys. The amount of type V and type VI collagens is higher in DKD and increases with the progression of the disease. The GBM contains lower amount of type IV collagen in DKD compared to normal tissue. Further, genetic variants in the α3 chain of type IV collagen may modulate susceptibility to DKD and end-stage kidney disease. Human cellular models of glomerular cells, analyses of human glomerular proteome, and improved microscopy procedures have been developed to investigate the molecular composition and organization of the human glomerular ECM.

Telmisartan alleviates collagen type III glomerulopathy: A case report with literature review

Collagen type III is commonly detected in the renal interstitium and vasculature; however, it is absent in healthy glomeruli. Deposition of collagen type III in the glomerular mesangium and capillary basement membranes may arise in two rare diseases, namely collagen type III glomerulopathy (CG) and nail patella syndrome. CG is a rare glomerular disease with no specific treatment, although supportive measures for control of hypertension and edema may help to relieve symptoms. With progression to end-stage renal disease, patients with CG may come to require dialysis and/or renal transplantation. The present study reported on a 59-year-old male who was diagnosed with CG nephrotic syndrome by immunohistochemical and electron microscopic examination of biopsy material. To the best of our knowledge, this is the first case reported in northeastern China. The angiotensin II blocker telmisartan was successfully used to alleviate renal symptoms and a literature review was performed. The present case supports the use of telmisartan as a first choice of treatment for CG.

Collagenofibrotic glomerulopathy - A rare disease diagnosed with the aid of transmission electron microscopy

Collagenofibrotic glomerulopathy (CFG) is a rare idiopathic kidney disease characterized by abnormal deposition of atypical Type III collagen fibers in the glomerulus causing subendothelial and mesangial expansion, manifesting as progressive renal dysfunction accompanied by proteinuria. The majority of CFG cases reported in literature are from Japan where this disease entity was initially recognized. There is an increased awareness and diagnosis of this rare renal disease in India with the recent increase in utilization of electron microscopy (EM) in clinical diagnostic settings. We describe a 28-year-old Bangladeshi woman who presented with hypertension and nephrotic range proteinuria not amenable to treatment with steroids and cyclophosphamide, whose renal biopsy demonstrated diagnostic ultrastructural features of CFG. This illustrative case is presented to highlight the role of EM analysis for diagnostic accuracy in renal biopsy evaluation in addition to demonstrating the unusual renal biopsy findings of this rare entity.

Unusual cause of glomerular deposition disease: Collagenofibrotic glomerulopathy

Collagenofibrotic glomerulopathy is a rare condition characterized by deposition of Type III collagen fibers in the subendothelial space and mesangium of the glomerulus. Only 17 cases have been reported from India. A definite diagnosis can only be established when typical histological findings are supported by electron microscopy. It is characterized by indolent progression and has no definitive therapy.