Renal Structure in Normoalbuminuric and Albuminuric Patients With Type 2 Diabetes and Impaired Renal Function

• Published in: Diabetes care Vol. 36; no. 11; pp. 3620 - 3626
• Main Authors: Ekinci, Elif I., Jerums, George, Skene, Alison, Crammer, Paul, Power, David, Cheong, Karey Y., Panagiotopoulos, Sianna, McNeil, Karen, Baker, Scott T., Fioretto, Paola, MacIsaac, Richard J.
• Format: Journal Article
• Language: English
• Published: Alexandria, VA American Diabetes Association 01.11.2013
• Subjects: Aged; Albuminuria; Albuminuria - etiology; Albuminuria - pathology; Associated diseases and complications; Biological and medical sciences; Biopsy; Care and treatment; Complications and side effects; Demographic aspects; Diabetes; Diabetes Mellitus, Type 2 - complications; Diabetes Mellitus, Type 2 - pathology; Diabetes. Impaired glucose tolerance; Diabetic Nephropathies - etiology; Diabetic Nephropathies - pathology; Diagnosis; Endocrine pancreas. Apud cells (diseases); Endocrinopathies; Female; Glomerular Filtration Rate; Humans; Kidney diseases; Kidney Glomerulus - pathology; Kidneys; Male; Medical sciences; Metabolic diseases; Nephrology. Urinary tract diseases; Original Research; Patients; Renal Insufficiency - etiology; Renal Insufficiency - pathology; Type 2 diabetes; Urinary system involvement in other diseases. Miscellaneous; Endocrinopathy; Type 2 diabetes; Human; Kidney disease; Urine; Urinary system disease; Renal function; Nutrition; Albumin; Patient; Metabolic diseases; Kidney; Concomitant disease; Urinary system; Diabetic nephropathy; Endocrinology
• DOI: 10.2337/dc12-2572
• ISSN: 0149-5992; 1935-5548

The structural basis of normoalbuminuric renal insufficiency in patients with type 2 diabetes remains to be elucidated. We compared renal biopsy findings in patients with type 2 diabetes and estimated glomerular filtration rate (eGFR) and measured GFR of <60 mL/min/1.73 m2, associated with either normo-, micro-, or macroalbuminuria. In patients with normo- (n = 8) or microalbuminuria (n = 6), renal biopsies were performed according to a research protocol. In patients with macroalbuminuria (n = 17), biopsies were performed according to clinical indication. Findings were categorized according to the Fioretto classification: category 1 (C1), normal/near normal; category 2 (C2), typical diabetic nephropathy (DN) with predominantly glomerular changes; and category 3 (C3), atypical with disproportionately severe interstitial/tubular/vascular damage and with no/mild diabetic glomerular changes. In our study population (mean eGFR 35 mL/min/1.73 m2), typical glomerular changes (C2) of DN were observed in 22 of 23 subjects with micro- or macroalbuminuria compared with 3 of 8 subjects with normoalbuminuria (P = 0.002). By contrast, predominantly interstitial or vascular changes (C3) were seen in only 1 of 23 subjects with micro- or macroalbuminuria compared with 3 of 8 normoalbuminuric subjects (P = 0.08). Mesangial area increased progressively from normal controls to patients with type 2 diabetes and normo-, micro-, and macroalbuminuria. Varying degrees of arteriosclerosis, although not necessarily the predominant pattern, were seen in seven of eight subjects with normoalbuminuria. Typical renal structural changes of DN were observed in patients with type 2 diabetes and elevated albuminuria. By contrast, in normoalbuminuric renal insufficiency, these changes were seen less frequently, likely reflecting greater contributions from aging, hypertension, and arteriosclerosis.