Impacts of Diabetes and an SGLT2 Inhibitor on the Glomerular Number and Volume in db/db Mice, as Estimated by Synchrotron Radiation Micro-CT at SPring-8.

BACKGROUND: Recent large-scale clinical studies demonstrate that sodium-glucose cotransporter 2 (SGLT2) inhibitors protect the diabetic kidney. However, clinical and animal studies have not shown the changes of the total glomeruli in the whole kidney treated with SGLT2 inhibitors. METHODS: We performed computed tomography (CT) imaging on mice using synchrotron radiation to investigate the impact of luseogliflozin, a SGLT2 inhibitor, on the number and volume of glomeruli in the whole kidney. FINDINGS: We did not observe a significant difference in the total glomerular number (Nglom) among mice. Luseogliflozin redistributed the number of glomeruli in different regions, accompanied by the normalization of diabetes-augmented renal volume (Vkidney). Diabetic db/db mice had a larger glomerular volume in the mid-cortex than did control db/m mice, and luseogliflozin increased the glomerular volume in all renal cortical zones of the whole kidney in db/db mice. According to the multivariate regression analysis, hemoglobin A1c level was the most relevant determinant of Vkidney, not Nglom or mean glomerular volume (Vglom), indicating that hyperglycemia induced renal (tubular) hypertrophy, but not glomerular enlargement. Luseogliflozin increased hypoxia in the juxtamedullary region, sustained upregulated renal renin expression and plasma renin activity, and failed to decrease albuminuria by downregulating megalin in db/db mice. INTERPRETATION: Based on our findings, SGLT2 inhibitors may alter glomerular distribution and size in addition to their glucose-lowering effects, presumably by affecting oxygen metabolism and humoral factors. FUND: Funding for this research was provided by The Japan Society for the Promotion of Science, the Japan Diabetes Foundation, and Asahikawa Medical University.

Pioglitazone reduces urinary albumin excretion in renin-angiotensin system inhibitor-treated type 2 diabetic patients with hypertension and microalbuminuria: the APRIME study.

BACKGROUND: The aim of his study was to compare the efficacy of pioglitazone with metformin on the reduction of albuminuria in type 2 diabetic patients with hypertension and microalbuminuria treated with renin-angiotensin system inhibitors (RAS-Is). METHODS: The open-label, randomized trial was performed in type 2 diabetic patients with hypertension and microalbuminuria. On the basis of the treatment with RAS-Is, 68 patients with microalbuminuria received either pioglitazone (15-30 mg/day; n = 32) or metformin (500-750 mg/day; n = 31) for 52 weeks. Urinary albumin-to-creatinine ratio (UACR) was measured every 12 weeks. RESULTS: After 52 weeks of treatment, the changes in the log-UACR from baseline were -8.3% in the pioglitazone group and +4.2% in the metformin group (p = 0.01), with similar glycemic and blood pressure changes. CONCLUSION: The combination of pioglitazone and RAS-Is showed therapeutic benefit in the reduction of urinary albumin excretion for type 2 diabetic patients with hypertension and microalbuminuria.

Insulin lispro reduces insulin antibodies in a patient with type 2 diabetes with immunological insulin resistance.

We describe a 54-year-old Japanese female with type 2 diabetes admitted to our hospital with poor metabolic control. On admission the patient's HbA1c was 9.1% despite having taken over 60 U of human insulin per day for the previous 10 years. A high titer of antibodies to insulin was detected in the serum, and therefore, we decided to introduce insulin lispro with the aim of minimizing immunogenicity. Over the next 2 months, the dosage of insulin required to achieve reasonable blood glucose control was reduced, with the HbA1c level decreasing significantly to 6.8%. The patient was subsequently withdrawn from insulin and discharged on diet therapy only. This case demonstrates that insulin lispro may ameliorate resistance to insulin therapy even in the presence of human insulin antibodies.