Renal Disease in Metabolic Syndrome: the Hidden Role of Intrarenal Ischemia

BackgroundThe pathogenesis of renal disease in obesity and metabolic syndrome (MS) is mostly unknown. This is in part the consequence of the limited information of renal morphological changes in these conditions. We evaluated renal histology in subjects with and without MS, participants of the European Nephrectomy Biobank (ENBiBA) project.MethodsMS was defined with at least three criteria: BMI ≥27 kg/m2; prediabetes: fasting glucose: 100-125 mg/dL or HbA1c >5.7%; systolic or diastolic blood pressure > 140/90 mmHg or the use of medications; triglycerides > 150 mg/dl or HDL cholesterol < 40 (men) or 50 mg/dl (women). The absence of these criteria defined patients without MS. Exclusion criteria were diabetes or known causes of renal disease.Results157 cases were evaluated: 49 without and 108 with MS. Those with MS were older (54±16 vs 66±11, p<0.0001) more prevalent CKD (eGFR < 60 ml/min): 24(23%) vs 4(8%), p=0.02 and higher albumin/creatinine ratio [10(4-68) vs 4.45(0-27), p=0.05] than those without. Global sclerosis [3%(1-7) vs 7%(3-13), p<0.0001], nodular sclerosis, mesangial expansion, glomerulomegaly; moderate+severe hyalinosis, and arteriosclerosis were more frequent in those with MS than in those without [88(82) vs 29(59); 83(77) vs 30(61), p<0.05]. These vascular changes were independent of differences in age.ConclusionsIn MS ischemic renal disease may play a role in renal disease. Also, some patients may develop lesions compatible with diabetic nephropathy such as increased mesangial expansion and nodular sclerosis. Further analyses are needed to study the consequences of the pandemic of obesity on renal health.