Effects of DPP-4 Inhibitors on Blood Glucose Variability in Japanese Patients with Type 2 Diabetes on Maintenance Hemodialysis: A Prospective Observational Exploratory Study.

INTRODUCTION: The precise blood glucose (BG) profile of hemodialysis patients is unclear, as is the effectiveness of dipeptidyl peptidase-4 (DPP-4) inhibitors in hemodialysis patients with type 2 diabetes. Here, we used continuous glucose monitoring (CGM) to evaluate BG variability in these patients and to assess the efficacy of DPP-4 inhibitors, particularly during hemodialysis sessions and at nighttime (UMIN000012638). METHODS: We examined BG profiles using CGM in 31 maintenance hemodialysis patients with type 2 diabetes. Differences between patients with and without DPP-4 inhibitors (n = 15 and 16, respectively) were analyzed using a linear mixed-effects model to assess changes in glucose levels in 5-min intervals. RESULTS: The model revealed that DPP-4 inhibitor use was significantly associated with suppression of a rapid drop in glucose levels, both with and without adjustment for BG levels at the start of hemodialysis. Moreover, the model revealed that the two groups differed significantly in the pattern of changes in BG levels from 0:00 to 6:55 am. DPP-4 inhibitors suppressed the tendency for subsequent nocturnal hypoglycemia. CONCLUSIONS: This prospective observational exploratory study showed that DPP-4 inhibitors could suppress BG variability during hemodialysis sessions as well as subsequent nocturnal changes in patients with type 2 diabetes. TRIAL REGISTRATION: ClinicalTrials.gov identifier, UMIN000012638.

Megalin-Mediated Tubuloglomerular Alterations in High-Fat Diet-Induced Kidney Disease.

Obesity, an important risk factor for metabolic syndrome (MetS) and cardiovascular disease, is often complicated by CKD, which further increases cardiovascular risk and causes ESRD. To elucidate the mechanism underlying this relationship, we investigated the role of the endocytic receptor megalin in proximal tubule epithelial cells (PTECs). We studied a high-fat diet (HFD)-induced obesity/MetS model using kidney-specific mosaic megalin knockout (KO) mice. Compared with control littermates fed a normal-fat diet, control littermates fed an HFD for 12 weeks showed autolysosomal dysfunction with autophagy impairment and increased expression of hypertrophy, lipid peroxidation, and senescence markers in PTECs of the S2 segment, peritubular capillary rarefaction with localized interstitial fibrosis, and glomerular hypertrophy with mesangial expansion. These were ameliorated in HFD-fed megalin KO mice, even though these mice had the same levels of obesity, dyslipidemia, and hyperglycemia as HFD-fed control mice. Intravital renal imaging of HFD-fed wild-type mice also demonstrated the accumulation of autofluorescent lipofuscin-like substances in PTECs of the S2 segment, accompanied by focal narrowing of tubular lumens and peritubular capillaries. In cultured PTECs, fatty acid-rich albumin induced the increased expression of genes encoding PDGF-B and monocyte chemoattractant protein-1 via megalin, with large (auto)lysosome formation, compared with fatty acid-depleted albumin. Collectively, the megalin-mediated endocytic handling of glomerular-filtered (lipo)toxic substances appears to be involved primarily in hypertrophic and senescent PTEC injury with autophagy impairment, causing peritubular capillary damage and retrograde glomerular alterations in HFD-induced kidney disease. Megalin could be a therapeutic target for obesity/MetS-related CKD, independently of weight, dyslipidemia, and hyperglycemia modification.

Chronic portal-systemic shunt encephalopathy in a hemodialysis patient treated with balloon-occluded retrograde transvenous obliteration.

We report a case of chronic portal-systemic shunt encephalopathy in a 79-year-old female hemodialysis patient with end-stage renal disease. Approximately 1 month before admission, she occasionally had a discrepant conversation. It was considered that hepatic encephalopathy was caused by an increase in the ammonia level in the blood flow of the shunt, which had been diagnosed 7 years previously between the splenic vein and the left renal vein. On admission, disturbed consciousness and an elevated serum ammonia level (221 µg/dl) were observed. No change in the shunt diameter was noted. Consciousness improved with conservative treatment, whereas hyperammonemia remained. Balloon-occluded retrograde transvenous obliteration (B-RTO) was performed on the shunt. As a result, hyperammonemia resolved immediately, and the level of ammonia was maintained at approximately 60 µg/dl. The patient often complained of drug-induced constipation; therefore, an increase in the intra-abdominal pressure in addition to ammonia production in the intestinal tract was suspected as the cause of encephalopathy. More than 23 months have passed since the B-RTO therapy, and no symptoms of encephalopathy have been observed yet.