Recent data have indicated the emerging role of glomerular autophagy in diabetic kidney disease. We aimed to assess the effect of the SGLT2 inhibitor empagliflozin, the DPP4 inhibitor linagliptin, and their combination, on glomerular autophagy in a model of type 2 diabetes. Eight-week-old male db/db mice were randomly assigned to treatment with empagliflozin, linagliptin, empagliflozin–linagliptin or vehicle for 8 weeks. Age-matched non-diabetic db/+ mice acted as controls. To estimate glomerular autophagy, immunohistochemistry for beclin-1 and LAMP-1 was performed. Podocyte autophagy was assessed by counting the volume density (Vv) of autophagosomes, lysosomes and autolysosomes by transmission electron microscopy. LC3B and LAMP-1, autophagy markers, and caspase-3 and Bcl-2, apoptotic markers, were evaluated in renal cortex by western blot. Vehicle-treated db/db mice had weak glomerular staining for beclin-1 and LAMP-1 and reduced Vv of autophagosomes, autolysosomes and lysosomes in podocytes. Empagliflozin and linagliptin, both as monotherapy and in combination, enhanced the areas of glomerular staining for beclin-1 and LAMP-1 and increased Vv of autophagosomes and autolysosomes in podocytes. Renal LC3B and Bcl-2 were restored in actively treated animals. LAMP-1 expression was enhanced in the empagliflozin group; caspase-3 expression decreased in the empagliflozin–linagliptin group only. Mesangial expansion, podocyte foot process effacement and urinary albumin excretion were mitigated by both agents. The data provide further explanation for the mechanism of the renoprotective effect of SGLT2 inhibitors and DPP4 inhibitors in diabetes.

Aim. To identify the clinical and metabolic factors associated with serum concentration of high sensitivity C-reactive protein (hsCRP) and α1-acid glycoprotein (α1-AGP) in patients with type 2 diabetes.Material and methods. The study involved 210 patients with type 2 diabetes. Levels of hsCRP and α1-AGP were measured using ELISA and compared with those of the control (30 healthy normal individuals). Levels of acute-phase proteins, fat mass and glucose variability (GV) were compared among demographic, anthropometric, biochemical and haematological parameters. The fat mass was determined with Dual-energy X-ray absorptiometry (DEXA). GV parameters including mean amplitude of glycaemic excursions, continuous overlapping net glycaemic action (CONGA), J-index, M-value and mean absolute glucose change (MAG) were derived from continuous glucose monitoring.Results. Levels of hsCRP and α1-AGP significantly increased (p 0.0001) in patients with diabetes compared with controls. hsCRP level positively correlated with total, truncal and android fat (r = 0.34, r = 0.28 and r = 0.31; respectively, p 0.00004). α1-AGP level showed no relationship with fat mass but positively correlated with mean glucose, CONGA, M-value and MAG (r = 0.38, r = 0.36, r = 0.43 and r = 0.4; respectively, p 0.0001). Patients with the highest hsCRP levels (75 percentile) had a greater body mass index (p = 0.00009) as well as truncal and android fat mass (p = 0.04 and p = 0.03, respectively) than those with the lowest levels (25 percentile). High level of α1-AGP (75 percentile) was associated with urinary albumin/creatinine ratio (p = 0.01) and GV indices (M-value: p = 0.02, MAG: p = 0.04).Conclusions. Levels of acute-phase proteins (hsCRP and α1-AGP) increased in patients with type 2 diabetes. Levels of hsCRP were associated with fat mass; meanwhile, α1-AGP levels were associated with short-time GV in these patients. The results lend support to the notion that both obesity and enhanced GV are involved in the development of chronic low-grade inflammation associated with type 2 diabetes.

A panel of cytokines and growth factors, mediating low-grade inflammation and fibrosis, was assessed in patients with type 2 diabetes (T2D) and different patterns of chronic kidney disease (CKD). Patients with long-term T2D (N = 130) were classified into four groups: no signs of CKD; estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m² without albuminuria; albuminuria and eGFR ≥60 mL/min/1.73 m²; albuminuria and eGFR <60 mL/min/1.73 m². Thirty healthy subjects were acted as control. Twenty-seven cytokines and growth factors were assessed in serum by multiplex bead array assay. Serum hs-CRP, urinary nephrin, podocine, and WFDC2 were measured by ELISA. Patients with T2D showed elevated IL-1Ra, IL-6, IL-17A, G-CSF, IP-10, MIP-1α, and bFGF levels; concentrations of IL-4, IL-12, IL-15, INF-γ, and VEGF were decreased. IL-6, IL-17A, G-CSF, MIP-1α, and bFGF correlated negatively with eGFR; IL-10 and VEGF demonstrated negative associations with WFDC2; no relationships with podocyte markers were found. Adjusted IL-17A and MIP-1α were predictors of non-albuminuric CKD, IL-13 predicted albuminuria with preserved renal function, meanwhile, IL-6 and hsCRP were predictors of albuminuria with eGFR decline. Therefore, albuminuric and non-albuminuric CKD in T2D patients are associated with different pro-inflammatory shifts in the panel of circulating cytokines.

Accumulating data indicate a role for the dysregulation of the cell cycle, autophagy and apoptosis in diabetic kidney disease. We aimed to evaluate the mediators of the PI3K/Akt and MAPK/ERK signaling pathways in the kidney of db/db mice, a model of type 2 diabetes, treated by the SGLT2 inhibitor empagliflozin, the DPP4 inhibitor linagliptin, and metformin. Eight-week-old male db/db mice were randomly assigned to treatment by these agents or vehicle for 8 weeks. Age-matched db/+ mice acted as controls. AMPKα1 and PI3Kp110β were evaluated in the renal cortex and medulla by Western Blot. Phosphorylated forms of principal molecules involved in the PI3K/Akt and MAPK/ERK pathways were assessed by multiplex analysis. Db/db mice had decreased PI3Kp110β, increased phospho-PTEN, HSP27 and MEK1 in the renal cortex and medulla, BAD in the renal cortex and decreased phospho-rpS6 in the renal medulla. Empagliflozin prevented the changes in the levels of cortical PI3Kp110β, phospho-MEK1, and medullar phospho-PTEN. Linagliptin restored PI3Kp110β levels. Both agents further decreased medullar phospho-rpS6. Metformin upregulated cortical AMPKα1, medullar PI3Kp110β, phospho-GSK-3α/β and MEK1, and increased phospho-HSP27 in the renal cortex and medulla. The data may provide further explanation of the mechanism underlying the development of diabetic kidney disease, as well as the renal protective effect of anti-diabetic agents.

Academy of Sciences, Novosibirsk, Russia 2Novosibirsk State Medical University, Novosibirsk, Russia BACKGROUND: Adipose tissue (AT) dysfunction plays an important role in metabolic disorders in obesity and type 2 diabetes. The role of distribution, hypertrophy and vascularization of AT in adipokine secretion disturbances remain to be clarified. AIMS: To determine the relationships between serum concentrations of adipokines and the mass and distribution of AT, diameter of adipocytes and vascularization of subcutaneous AT in patients with type 2 diabetes. MATERIALS AND METHODS: A total of 125 patients were examined, including 82 subjects with obesity. Thirty persons without diabetes and obesity, matched by sex and age, were acted as control. Concentrations of leptin, resistin, visfatin, adipsin and adiponectin in fasting serum were determined using multiplex analysis. Mass and distribution of AT was assessed by dual-energy X-ray absorptiometry. Samples of SAT were obtained from umbilical region using a knife biopsy in 25 patients and in 15 individuals who died in accidents. Blood and lymphatic vessels in SAT were revealed with immunohistochemistry, using antibody to CD-34 and podoplanin respectively. The volume and numerical density, ultrastructure of blood and lymphatic vessels, and mean diameter of subcutaneous adipocytes were evaluated. RESULTS: Patients with diabetes, as compared to control, had significantly higher levels of leptin, resistin, adipsin and visfatin (all p0.001). Adiponectin showed no differences. Concentrations of leptin, resistin, visfatin, adipsin and adiponectin correlated positively with gynoid fat mass. Additionally, leptin and adipsinshowed positive correlations with truncal and central abdominal fat mass. Concentration of leptin, but not other adipokines, was associated with hypertrophy of subcutaneous adipocytes. A decrease in volumetric density of microvessels(р=0.01) and increase in volume and numerical density of lymphatic vessels (both р=0.02) was observed in subcutaneous AT from diabetic subjects. The swelling of cytoplasm, mitochondria, cisterns of granular endoplasmic reticulum and reduced content of micropinocytotic vesicles was revealed in lymphatic capillaries. Resistin and visfatin showed inverse associations with density of microvessels. CONCLUSION: Endocrine dysfunction of AT in patients with type 2 diabetes, manifested by elevation of serum concentrations of leptin, resistin, visfatin and adipsin, is associated with mass and distribution of AT, hypertrophy of subcutaneous adipocytes and vascularization abnormalities of subcutaneous AT.