Preventive effects of vasohibin-2-targeting peptide vaccine for diabetic nephropathy.

Diabetic nephropathy remains the leading cause of end-stage kidney disease in many countries, and additional therapeutic targets are needed to prevent its development and progression. Some angiogenic factors are involved in the pathogenesis of diabetic nephropathy. Vasohibin-2 (VASH2) is a novel proangiogenic factor, and our previous study showed that glomerular damage is inhibited in diabetic Vash2 homozygous knockout mice. Therefore, we established a VASH2-targeting peptide vaccine as a tool for anti-VASH2 therapy in diabetic nephropathy. In this study, the preventive effects of the VASH2-targeting peptide vaccine against glomerular injury were examined in a streptozotocin (STZ)-induced diabetic mouse model. The mice were subcutaneously injected with the vaccine at two doses 2 wk apart and then intraperitoneally injected with 50 mg/kg STZ for 5 consecutive days. Glomerular injury was evaluated 20 wk after the first vaccination. Treatment with the VASH2-targeting peptide vaccine successfully induced circulating anti-VASH2 antibody without inflammation in major organs. Although the vaccination did not affect blood glucose levels, it significantly prevented hyperglycemia-induced increases in urinary albumin excretion and glomerular volume. The vaccination did not affect increased VASH2 expression but significantly inhibited renal angiopoietin-2 (Angpt2) expression in the diabetic mice. Furthermore, it significantly prevented glomerular macrophage infiltration. The preventive effects of vaccination on glomerular injury were also confirmed in db/db mice. Taken together, the results of this study suggest that the VASH2-targeting peptide vaccine may prevent diabetic glomerular injury in mice by inhibiting Angpt2-mediated microinflammation.NEW & NOTEWORTHY This study demonstrated preventive effects of VASH2-targeting peptide vaccine therapy on albuminuria and glomerular microinflammation in STZ-induced diabetic mouse model by inhibiting renal Angpt2 expression. The vaccination was also effective in db/db mice. The results highlight the importance of VASH2 in the pathogenesis of early-stage diabetic nephropathy and the practicability of anti-VASH2 strategy as a vaccine therapy.

Tangshen formula protects against podocyte apoptosis via enhancing the TFEB-mediated autophagy-lysosome pathway in diabetic nephropathy.

ETHNOPHARMACOLOGICAL RELEVANCE: Diabetic nephropathy (DN) is the leading cause of end-stage kidney disease and currently there are no specific and effective drugs for its treatment. Podocyte injury is a detrimental feature and the major cause of albuminuria in DN. We previously reported Tangshen Formula (TSF), a Chinese herbal medicine, has shown therapeutic effects on DN. However, the underlying mechanisms remain obscure. AIM OF THE STUDY: This study aimed to explore the protective effect of TSF on podocyte apoptosis in DN and elucidate the potential mechanism. MATERIALS AND METHODS: The effects of TSF were assessed in a murine model using male KKAy diabetic mice, as well as in advanced glycation end products-stimulated primary mice podocytes. Transcription factor EB (TFEB) knockdown primary podocytes were employed for mechanistic studies. In vivo and in vitro studies were performed and results assessed using transmission electron microscopy, immunofluorescence staining, and western blotting. RESULTS: TSF treatment alleviated podocyte apoptosis and structural impairment, decreased albuminuria, and mitigated renal dysfunction in KKAy mice. Notably, TSF extracted twice showed a more significant reduction in proteinuria than TSF extracted three times. Accumulation of autophagic biomarkers p62 and LC3, and aberrant autophagic flux in podocytes of DN mice were significantly altered by TSF therapy. Consistent with the in vivo results, TSF prevented the apoptosis of primary podocytes exposed to AGEs and activated autophagy. However, the anti-apoptosis capacity of TSF was countered by the autophagy-lysosome inhibitor chloroquine. We found that TSF increased the nuclear translocation of TFEB in diabetic podocytes, and thus upregulated transcription of its several autophagic target genes. Pharmacological activation of TFEB by TSF accelerated the conversion of autophagosome to autolysosome and lysosomal biogenesis, further augmented autophagic flux. Conversely, TFEB knockdown negated the favorable effects of TSF on autophagy in AGEs-stimulated primary podocytes. CONCLUSIONS: These findings indicate TSF appears to attenuate podocyte apoptosis and promote autophagy in DN via the TFEB-mediated autophagy-lysosome system. Thus, TSF may be a therapeutic candidate for DN.

Cyclooxygenase-2 inhibition prevents renal toxicity but not hypertension during sunitinib treatment.

BACKGROUND: Anticancer angiogenesis inhibitors cause hypertension and renal injury. Previously we observed in rats that high-dose aspirin (capable of blocking cyclooxygenase (COX)-1 and-2) was superior to low-dose aspirin (blocking COX-1 only) to prevent these side-effects during treatment with the angiogenesis inhibitor sunitinib, suggesting a role for COX-2. High-dose aspirin additionally prevented the rise in COX-derived prostacyclin (PGI2). Therefore, we studied the preventive effects of selective COX-2 inhibition and the hypothesized contributing role of PGI2 during angiogenesis inhibition. METHODS: Male WKY rats received vehicle, sunitinib ((SU), 14 mg/kg/day) alone or combined with COX-2 inhibition (celecoxib, 10 mg/kg/day) or a PGI2 analogue (iloprost, 100 µg/kg/day) for 8 days (n = 8-9 per group). Mean arterial pressure (MAP) was measured via radiotelemetry, biochemical measurements were performed via ELISA and vascular function was assessed via wire myography. RESULTS: SU increased MAP (17±1mmHg versus 3±1mmHg after vehicle on day 4, P < 0.002), which could not be significantly blunted by celecoxib (+12±3mmHg on day 4, P = 0.247), but was temporarily attenuated by iloprost (treatment days 1 + 2 only). Urinary PGI2 (996 ± 112 versus 51 ± 11ng/24h after vehicle, P < 0.001), but not circulating PGI2 increased during SU, which remained unaffected by celecoxib and iloprost. Celecoxib reduced sunitinib-induced albuminuria (0.36 ± 0.05 versus 0.58 ± 0.05mg/24h after SU, P = 0.005). Wire myography demonstrated increased vasoconstriction to endothelin-1 after SU (Emax P = 0.005 versus vehicle), which remained unaffected by celecoxib or iloprost. CONCLUSION: Selective COX-2 inhibition ameliorates albuminuria during angiogenesis inhibition with sunitinib, which most likely acts independently of PGI2. To combat angiogenesis inhibitor-induced hypertension, dual rather than selective COX-1/2 blockade seems preferential.

A diet containing cod backbone proteins attenuated the development of mesangial sclerosis and tubular dysfunction in male obese BTBR ob/ob mice.

PURPOSE: The obese black and tan, brachyuric (BTBR) ob/ob mouse spontaneously develops features comparable to human diabetic nephropathy. The primary aim of the present study was to investigate if a diet containing fish proteins would attenuate or delay the development of glomerular hypertrophy (glomerulomegaly), mesangial sclerosis and albuminuria in obese BTBR ob/ob mice. METHODS: Obese BTBR.CgLepob/WiscJ male mice were fed diets containing 25% of protein from Atlantic cod backbones and 75% of protein from casein (Cod-BB group), or casein as the sole protein source (control group). Kidneys were analysed morphologically, and markers for renal dysfunction were analysed biochemically in urine and serum. RESULTS: The Cod-BB diet attenuated the development of mesangial sclerosis (P 0.040) without affecting the development of glomerular hypertrophy and albuminuria. The urine concentration of cystatin C (relative to creatinine) was lower in mice fed the Cod-BB diet (P 0.0044). CONCLUSION: A diet containing cod backbone protein powder attenuated the development of mesangial sclerosis and tubular dysfunction in obese BTBR ob/ob mice, but did not prevent the development of glomerular hypertrophy and albuminuria in these mice.

Mediators between canagliflozin and renoprotection vary depending on patient characteristics: Insights from the CREDENCE trial.

AIM: To identify the mediators between canagliflozin and renoprotection in patients with type 2 diabetes at a high risk of end-stage kidney disease (ESKD). METHODS: In this post hoc analysis of the CREDENCE trial, the effect of canagliflozin on potential mediators (42 biomarkers) at 52 weeks and the association between changes in mediators and renal outcomes were evaluated using mixed-effects and Cox models, respectively. The renal outcome was a composite of ESKD, serum creatinine doubling or renal death. The percentage of the mediating effect of each significant mediator was calculated based on changes in the hazard ratios of canagliflozin after additional adjustment of the mediator. RESULTS: Changes in haematocrit, haemoglobin, red blood cell (RBC) count and urinary albumin-to-creatinine ratio (UACR) at 52 weeks significantly mediated 47%, 41%, 40% and 29% risk reduction with canagliflozin, respectively. Further, 85% mediation was attributed to the combined effect of haematocrit and UACR. A large variation in mediating effects by haematocrit change existed among the subgroups, ranging from 17% in those patients with a UACR of more than 3000 mg/g to 63% in patients with a UACR of 3000 mg/g or less. In the subgroups with a UACR of more than 3000 mg/g, UACR change was the highest mediating factor (37%), driven by the strong association between UACR decline and renal risk reduction. CONCLUSIONS: The renoprotective effects of canagliflozin in patients at a high risk of ESKD can be significantly explained by changes in RBC variables and UACR. The complementary mediating effects of RBC variables and UACR may support the renoprotective effect of canagliflozin in different patient groups.

Kidney protection with canagliflozin: A combined analysis of the randomized CANVAS program and CREDENCE trials.

AIM: In the CANVAS Program and CREDENCE trials, the sodium glucose co-transporter 2 inhibitor canagliflozin reduced the risk of cardiovascular and kidney events in patients with type 2 diabetes. The current study analysed a pooled population to ascertain the kidney protection provided by canagliflozin across the full spectrum of kidney parameters. METHODS: This post-hoc pooled analysis of the CANVAS Program (N = 10 142) and CREDENCE trial (N = 4401), assessed the risk of the primary kidney composite (doubling of serum creatinine, end-stage kidney disease, renal death), in all patients and subgroups defined by baseline estimated glomerular filtration rate (<30, 30 to <45, 45 to <60 and ≥60 ml/min/1.73 m2 ), albuminuria [<30, 30-300, >300 mg/g (<3.39, 3.39-33.9, >33.9 mg/mmol)] and 2012 Kidney Disease: Improving Global Outcomes (KDIGO) classification of chronic kidney disease (low/moderate, high and very high risk). RESULTS: In the overall population, the risk for the primary kidney composite outcome was 37% lower in the canagliflozin group versus placebo (HR: 0.63; 95% CI: 0.53, 0.77; p < .001). There was no evidence of heterogeneity in the kidney protective effects of canagliflozin across a range of kidney risks when stratified by baseline estimated glomerular filtration rate, albuminuria or KDIGO risk category (all pinteraction > .05). A statistically significant risk reduction of the primary kidney composite outcome was sustained by approximately 18 months after randomization. CONCLUSIONS: These results emphasize a critical role of canagliflozin in kidney protection across a broad spectrum of participants with type 2 diabetes with varying levels of kidney function.

Effects of sodium-glucose cotransporter 2 inhibitors, mineralocorticoid receptor antagonists, and their combination on albuminuria in diabetic patients.

AIMS: Diabetes mellitus (DM) is the leading cause of chronic kidney disease. Albuminuria is associated with an increased risk of cardiovascular mortality. Sodium-glucose cotransporter 2 inhibitors (SGLT2-Is) and mineralocorticoid receptor antagonists (MRAs) protect against albuminuria; however, their combined effects on albuminuria are unclear. We performed a network meta-analysis to investigate the effects of SGLT2-Is, MRAs and their combination on albuminuria in type 2 DM. METHODS: We systematically searched PubMed, Medline, EMBASE and the Cochrane Library from inception up to 20 November 2022. We selected randomized control and crossover trials that compared MRAs, SGLT2-Is, MRAs + SGLT2-Is, or a placebo in patients with type 2 DM with a urinary albumin-creatinine ratio (UACR) ≥30 mg/g creatinine. The primary outcome was the change in the UACR. RESULTS: This meta-analysis analysed 17 studies with 34 412 patients. The use of combination treatment with SGLT2-Is and MRAs was associated with lower albuminuria compared with the use of SGLT2-Is, MRAs, or the placebo alone [mean difference (95% CI): -34.19 (-27.30; -41.08), -32.25 (-24.53; -39.97) and -65.22 (-57.97; -72.47), respectively]. Treatment with SGLT2-Is or MRAs alone caused a significant reduction in UACR compared with the placebo [mean difference (95% CI): -31.03 (-28.35; -33.72) and -32.97 (-29.68; -36.27), respectively]. The effects of MRAs on the UACR are comparable with those of SGLT2-Is. Sensitivity analyses showed similar results. CONCLUSION: Combination therapy with SGLT2-Is and MRAs was associated with lower albuminuria in patients with type 2 DM compared with monotherapy with SGLT2-Is or MRAs alone.

"Positive Kidney Health": Implementation and design of a pharmacist-led intervention for patients at risk for development or progression of chronic kidney disease.

BACKGROUND: Patients with early chronic kidney disease (CKD) or underlying risk factors are often unaware of their kidney test results, common causes of CKD, and ways to lower risk of disease onset/progression. OBJECTIVE: To test feasibility of a pharmacist-led intervention targeting patient education and risk factors in patients with early CKD and those at risk for CKD. PRACTICE DESCRIPTION: Ambulatory care pharmacists in community-based primary care clinics delivered kidney health education, ordered labs, and recommended medication adjustments. PRACTICE INNOVATION: We identified patients with a moderate rate of decline (≥2 mL/min/1.73 m2 per year) in estimated glomerular filtration (eGFR) at-risk for CKD or early stage CKD. An interactive workbook was designed to teach patients about kidney test results and self-management of risk factors including hypertension, type 2 diabetes, cigarette smoking, and chronic oral nonsteroidal anti-inflammatory drug use. EVALUATION METHODS: Outcomes included visit uptake, completion of annual albuminuria screening, and initiation of guideline-directed medications for CKD. Patients were surveyed pre- and post-intervention for kidney health knowledge and perceptions regarding pharmacist-provided information. RESULTS: Our sample of 20 participants had a mean eGFR of 59 mL/min/1.73 m2 and the mean eGFR decline was -4.6 mL/min/1.73 m2 per year. There were 47 visits during the pilot period from February 2021 to October 2021. Thirteen patients were missing albuminuria screening within 12 months; 2 of 9 patients with resulting labs had new microalbuminuria and were started on renoprotective medications. Patients had improved understanding of their kidney function test results and most did not consider the information scary or confusing. CONCLUSION: Barriers to enrollment included fewer participants with multiple risk factors for CKD. The pharmacists were able to engage patients in learning the importance of monitoring and self-management of kidney health. A collaborative practice agreement may enhance a similar intervention that includes initiation of renoprotective medications.

Myeloid expression of the anti-apoptotic protein Mcl1 is required in anti-myeloperoxidase vasculitis but myeloperoxidase inhibition is not protective.

Antibodies to neutrophil and monocyte myeloperoxidase and proteinase 3 are a feature of anti-neutrophil cytoplasmic antibody vasculitis, a disease with significant morbidity for which new treatments are needed. Mice with a myeloid-specific deletion of the anti-apoptotic protein Mcl1 have reduced numbers of circulating neutrophils. Here, we assessed if myeloid-specific Mcl1 was required in murine anti-myeloperoxidase vasculitis and whether inhibition of myeloperoxidase was protective. In a murine model of anti-neutrophil cytoplasmic antibody vasculitis, induced by anti-myeloperoxidase antibody, mice with a myeloid-specific deletion of Mcl1 were protected from disease. They had fewer crescents, neutrophils, and macrophages in the glomeruli, lower serum creatinine levels and reduced albuminuria compared with controls. At baseline and day six after disease induction they had fewer circulating neutrophils than controls. At day six there were also fewer circulating monocytes. Myeloperoxidase inhibition with AZD5904 had no effect on histological or biochemical parameters of disease, and there was also no reduction in albuminuria at day one, two, five or seven after disease induction. These findings persisted when disease was induced without granulocyte-colony stimulating factor, which increases disease severity. A second myeloperoxidase inhibitor, AZM198, also showed no evidence of an effect, although both AZD5904 and AZM198 inhibited human neutrophil extracellular trap formation in vitro. Thus, our results show that while myeloid-specific Mcl1 is required in this model of anti-myeloperoxidase vasculitis, myeloperoxidase inhibition is not protective.

Initiation of the SGLT2 inhibitor canagliflozin to prevent kidney and heart failure outcomes guided by HbA1c, albuminuria, and predicted risk of kidney failure.

BACKGROUND: Sodium glucose co-transporter-2 (SGLT2) inhibitors reduce the risk of kidney and heart failure events independent of glycemic effects. We assessed whether initiation of the SGLT2 inhibitor canagliflozin guided by multivariable predicted risk based on clinical characteristics and novel biomarkers is more efficient to prevent clinical outcomes compared to a strategy guided by HbA1c or urinary-albumin-creatinine ratio (UACR) alone. METHODS: We performed a post-hoc analysis of the CANVAS trial including 3713 patients with available biomarker measurements. We compared the number of composite kidney (defined as a sustained 40% decline in eGFR, chronic dialysis, kidney transplantation, or kidney death) and composite heart failure outcomes (defined as heart failure hospitalization or cardiovascular (CV) death) prevented per 1000 patients treated for 5 years when canagliflozin was initiated in patients according to HbA1c ≥ 7.5%, UACR, or multivariable risk models consisting of: (1) clinical characteristics, or (2) clinical characteristics and novel biomarkers. Differences in the rates of events prevented between strategies were tested by Chi2-statistic. RESULTS: After a median follow-up of 6.1 years, 144 kidney events were recorded. The final clinical model included age, previous history of CV disease, systolic blood pressure, UACR, hemoglobin, body weight, albumin, estimated glomerular filtration rate, and randomized treatment assignment. The combined biomarkers model included all clinical characteristics, tumor necrosis factor receptor-1, kidney injury molecule-1, matrix metallopeptidase-7 and interleukin-6. Treating all patients with HbA1c ≥ 7.5% (n = 2809) would prevent 33.0 (95% CI 18.8 to 43.3 ) kidney events at a rate of 9.6 (95% CI 5.5 to 12.6) events prevented per 1000 patients treated for 5 years. The corresponding rates were 5.8 (95% CI 3.4 to 7.9), 16.6 (95% CI 9.5 to 22.0) (P < 0.001 versus HbA1c or UACR approach), and 17.5 (95% CI 10.0 to 23.0) (P < 0.001 versus HbA1c or UACR approach; P = 0.54 versus clinical model). Findings were similar for the heart failure outcome. CONCLUSION: Initiation of canagliflozin based on an estimated risk-based approach prevented more kidney and heart failure outcomes compared to a strategy based on HbA1c or UACR alone. There was no apparent gain from adding novel biomarkers to the clinical risk model. These findings support the use of risk-based assessment using clinical markers to guide initiation of SGLT2 inhibitors in patients with type 2 diabetes.

Role of Axl in target organ inflammation and damage due to hypertensive aortic remodeling.

We have shown that excessive endothelial cell stretch causes release of growth arrest-specific 6 (GAS6), which activates the tyrosine kinase receptor Axl on monocytes and promotes immune activation and inflammation. We hypothesized that GAS6/Axl blockade would reduce renal and vascular inflammation and lessen renal dysfunction in the setting of chronic aortic remodeling. We characterized a model of aortic remodeling in mice following a 2-wk infusion of angiotensin II (ANG II). These mice had chronically increased pulse wave velocity, and their aortas demonstrated increased mural collagen. Mechanical testing revealed a marked loss of Windkessel function that persisted for 6 mo following ANG II infusion. Renal function studies showed a reduced ability to excrete a volume load, a progressive increase in albuminuria, and tubular damage as estimated by periodic acid Schiff staining. Treatment with the Axl inhibitor R428 beginning 2 mo after ANG II infusion had a minimal effect on aortic remodeling 2 mo later but reduced the infiltration of T cells, γ/δ T cells, and macrophages into the aorta and kidney and improved renal excretory capacity, reduced albuminuria, and reduced evidence of renal tubular damage. In humans, circulating Axl+/Siglec6+ dendritic cells and phospho-Axl+ cells correlated with pulse wave velocity and aortic compliance measured by transesophageal echo, confirming chronic activation of the GAS6/Axl pathway. We conclude that brief episodes of hypertension induce chronic aortic remodeling, which is associated with persistent low-grade inflammation of the aorta and kidneys and evidence of renal dysfunction. These events are mediated at least in part by GAS6/Axl signaling and are improved with Axl blockade.NEW & NOTEWORTHY In this study, a brief, 2-wk period of hypertension in mice led to progressive aortic remodeling, an increase in pulse wave velocity, and evidence of renal injury, dysfunction, and albuminuria. This end-organ damage was associated with persistent renal and aortic infiltration of CD8+ and γ/δ T cells. We show that this inflammatory response is likely due to GAS6/Axl signaling and can be ameliorated by blocking this pathway. We propose that the altered microvascular mechanical forces caused by increased pulse wave velocity enhance GAS6 release from the endothelium, which in turn activates Axl on myeloid cells, promoting the end-organ damage associated with aortic stiffening.

Glycemia Reduction in Type 2 Diabetes - Microvascular and Cardiovascular Outcomes.

BACKGROUND: Data are lacking on the comparative effectiveness of commonly used glucose-lowering medications, when added to metformin, with respect to microvascular and cardiovascular disease outcomes in persons with type 2 diabetes. METHODS: We assessed the comparative effectiveness of four commonly used glucose-lowering medications, added to metformin, in achieving and maintaining a glycated hemoglobin level of less than 7.0% in participants with type 2 diabetes. The randomly assigned therapies were insulin glargine U-100 (hereafter, glargine), glimepiride, liraglutide, and sitagliptin. Prespecified secondary outcomes with respect to microvascular and cardiovascular disease included hypertension and dyslipidemia, confirmed moderately or severely increased albuminuria or an estimated glomerular filtration rate of less than 60 ml per minute per 1.73 m2 of body-surface area, diabetic peripheral neuropathy assessed with the Michigan Neuropathy Screening Instrument, cardiovascular events (major adverse cardiovascular events [MACE], hospitalization for heart failure, or an aggregate outcome of any cardiovascular event), and death. Hazard ratios are presented with 95% confidence limits that are not adjusted for multiple comparisons. RESULTS: During a mean 5.0 years of follow-up in 5047 participants, there were no material differences among the interventions with respect to the development of hypertension or dyslipidemia or with respect to microvascular outcomes; the mean overall rate (i.e., events per 100 participant-years) of moderately increased albuminuria levels was 2.6, of severely increased albuminuria levels 1.1, of renal impairment 2.9, and of diabetic peripheral neuropathy 16.7. The treatment groups did not differ with respect to MACE (overall rate, 1.0), hospitalization for heart failure (0.4), death from cardiovascular causes (0.3), or all deaths (0.6). There were small differences with respect to rates of any cardiovascular disease, with 1.9, 1.9, 1.4, and 2.0 in the glargine, glimepiride, liraglutide, and sitagliptin groups, respectively. When one treatment was compared with the combined results of the other three treatments, the hazard ratios for any cardiovascular disease were 1.1 (95% confidence interval [CI], 0.9 to 1.3) in the glargine group, 1.1 (95% CI, 0.9 to 1.4) in the glimepiride group, 0.7 (95% CI, 0.6 to 0.9) in the liraglutide group, and 1.2 (95% CI, 1.0 to 1.5) in the sitagliptin group. CONCLUSIONS: In participants with type 2 diabetes, the incidences of microvascular complications and death were not materially different among the four treatment groups. The findings indicated possible differences among the groups in the incidence of any cardiovascular disease. (Funded by the National Institute of Diabetes and Digestive and Kidney Diseases and others; GRADE ClinicalTrials.gov number, NCT01794143.).

Blocking CHOP-dependent TXNIP shuttling to mitochondria attenuates albuminuria and mitigates kidney injury in nephrotic syndrome.

Albuminuria is a hallmark of glomerular disease of various etiologies. It is not only a symptom of glomerular disease but also a cause leading to glomerulosclerosis, interstitial fibrosis, and eventually, a decline in kidney function. The molecular mechanism underlying albuminuria-induced kidney injury remains poorly defined. In our genetic model of nephrotic syndrome (NS), we have identified CHOP (C/EBP homologous protein)-TXNIP (thioredoxin-interacting protein) as critical molecular linkers between albuminuria-induced ER dysfunction and mitochondria dyshomeostasis. TXNIP is a ubiquitously expressed redox protein that binds to and inhibits antioxidant enzyme, cytosolic thioredoxin 1 (Trx1), and mitochondrial Trx2. However, very little is known about the regulation and function of TXNIP in NS. By utilizing Chop-/- and Txnip-/- mice as well as 68Ga-Galuminox, our molecular imaging probe for detection of mitochondrial reactive oxygen species (ROS) in vivo, we demonstrate that CHOP up-regulation induced by albuminuria drives TXNIP shuttling from nucleus to mitochondria, where it is required for the induction of mitochondrial ROS. The increased ROS accumulation in mitochondria oxidizes Trx2, thus liberating TXNIP to associate with mitochondrial nod-like receptor protein 3 (NLRP3) to activate inflammasome, as well as releasing mitochondrial apoptosis signal-regulating kinase 1 (ASK1) to induce mitochondria-dependent apoptosis. Importantly, inhibition of TXNIP translocation and mitochondrial ROS overproduction by CHOP deletion suppresses NLRP3 inflammasome activation and p-ASK1-dependent mitochondria apoptosis in NS. Thus, targeting TXNIP represents a promising therapeutic strategy for the treatment of NS.

Low-dose hydralazine reduces albuminuria and glomerulosclerosis in a mouse model of obesity-related chronic kidney disease.

AIM: To determine, using a mouse model of obesity, whether low-dose hydralazine prevents obesity-related chronic kidney disease (CKD). METHODS: From 8 weeks of age, male C57BL/6 mice received a high-fat diet (HFD) or chow, with or without low-dose hydralazine (25 mg/L) in drinking water, for 24 weeks. Biometric and metabolic variables, renal function and structural changes, renal global DNA methylation, DNA methylation profile and markers of renal fibrosis, injury, inflammation and oxidative stress were assessed. RESULTS: The HFD-fed mice developed obesity, with glucose intolerance, hyperinsulinaemia and dyslipidaemia. Obesity increased albuminuria and glomerulosclerosis, which were significantly ameliorated by low-dose hydralazine in the absence of a blood pressure-lowering effect. Obesity increased renal global DNA methylation and this was attenuated by low-dose hydralazine. HFD-induced changes in methylation of individual loci were also significantly reversed by low-dose hydralazine. Obese mice demonstrated increased markers of kidney fibrosis, inflammation and oxidative stress, but these markers were not significantly improved by hydralazine. CONCLUSION: Low-dose hydralazine ameliorated HFD-induced albuminuria and glomerulosclerosis, independent of alterations in biometric and metabolic variables or blood pressure regulation. Although the precise mechanism of renoprotection in obesity is unclear, an epigenetic basis may be implicated. These data support repurposing hydralazine as a novel therapy to prevent CKD progression in obese patients.

Pentosan polysulfate exerts anti-inflammatory effect and halts albuminuria progression in diabetic nephropathy: Role of combined losartan.

Pentosan polysulfate sodium (PPS) is a polysulfated glycosaminoglycan approved for the treatment of interstitial cystitis. It also showed renoprotective effects in chronic kidney injury models, for example, 5/6 nephrectomy and diabetic nephropathy (DN). In the present study, we addressed to evaluate the therapeutic value of PPS in DN of rats in combination with losartan (LSR). Sixty male Sprague-Dawley rats were randomly divided into six groups: control group, untreated diabetic groups (8 and 16 weeks after diabetes induction by streptozotocin "STZ", 60 mg/kg, intraperitoneal [I.P.]), LSR-treated diabetic group (10 mg/kg/day, P.O.), PPS-treated diabetic group (25 mg/kg/day, P.O.), and combination-treated diabetic group. Drug treatment was started 8 weeks after induction of diabetes and continued for a further 8 weeks. Renal functions, albuminuria, renal IL-6, oxidative stress, and renal histopathology were evaluated. STZ-treated diabetic rats developed progressive albuminuria, renal dysfunction, and significant glomerular change 16 weeks after induction of diabetes. Administration of PPS, alone or in combination with LSR, showed some beneficial effects on DN evolution and significantly decreased renal inflammation as detected by IL-6 level. The best beneficial effect on DN evolution was obtained by PPS sole therapy based on albuminuria evaluation and renal histopathology. However, the combination of PPS and LSR did not show additive benefits. This study reported that the renoprotection of PPS in the setting of DN is evident by exerting anti-inflammatory and antioxidant effects, but this effect could be masked when combined with an angiotensin receptor blocker.

Association Between SGLT2 Inhibitors vs DPP4 Inhibitors and Renal Outcomes Among Patients With Type 2 Diabetes.

CONTEXT: Diabetic kidney disease is a major burden among diabetic patients. Sodium-glucose cotransporter 2 inhibitors (SGLT2is) were shown to reduce renal outcomes in clinical trials and real-world studies. However, head-to-head comparisons with individual classes of glucose-lowering agents warranted further investigation. OBJECTIVE: This work aimed to investigate the associations between SGLT2is use vs dipeptidyl peptidase-4 inhibitors (DPP4is) use and 4 renal outcomes: end-stage renal disease (ESRD), albuminuria, acute renal failure (ARF), and the rate of estimated glomerular filtration rate (eGFR) change using a territory-wide electronic medical database in Hong Kong. METHODS: For this retrospective cohort study, the "prevalent new-user" design was adopted to account for previous exposure to study drugs. Propensity score matching was used to balance baseline characteristics. Electronic health data of type 2 diabetes patients using SGLT2is and DPP4is between 2015 and 2018 were collected. RESULTS: The matched cohort consisted of 6333 SGLT2is users and 25 332 DPP4is users, with a median follow-up of 3.8 years. Compared to DPP4is, SGLT2is use was associated with lower risks of ESRD (hazard ratio [HR]: 0.51; 95% CI, 0.42-0.62; P < .001) and ARF (HR: 0.59; 95% CI, 0.48-0.73; P < .001), and a slower decline in eGFR. The associations remained statistically significant among patients with or without rapid eGFR decline and patients who added or switched to SGLT2is from DPP4is. The association with albuminuria was inconsistent across analyses. CONCLUSION: Compared to DPP4is, SGLT2is use was associated with reduced risks of ESRD and ARF, and a slower eGFR decline in a real-world setting. The associations remained statistically significant in patients with or without preindex rapid eGFR decline.

Non-canonical Wnt/calcium signaling is protective against podocyte injury and glomerulosclerosis.

Activation of canonical Wnt signaling has been implicated in podocyte injury and proteinuria. As Wnts are secreted proteins, whether Wnts derived from podocytes are obligatory for promoting proteinuria remains unknown. To address this, we generated conditional knockout mice where Wntless, a cargo receptor protein required for Wnt secretion, was specifically deleted in glomerular podocytes. Mice with podocyte-specific ablation of Wntless (Podo-Wntless-/-) were phenotypically normal. However, after inducing kidney damage with Adriamycin for six days, Podo-Wntless-/- mice developed more severe podocyte injury and albuminuria than their control littermates. Surprisingly, ablation of Wntless resulted in upregulation of ß-catenin, accompanied by reduction of nephrin, podocin, podocalyxin, and Wilms tumor 1 proteins. In chronic injury induced by Adriamycin, increased albuminuria, aggravated podocyte lesions and extracellular matrix deposition were evident in Podo-Wntlessl-/- mice, compared to wild type mice. Mechanistically, specific ablation of Wntless in podocytes caused down-regulation of the nuclear factor of activated T cell 1 (NFAT1) and Nemo-like kinase (NLK), key downstream mediators of non-canonical Wnt/calcium signaling. In vitro, knockdown of either NFAT1 or NLK induced ß-catenin activation while overexpression of NLK significantly repressed ß-catenin induction and largely preserved nephrin in glomerular podocytes. Thus, our results indicate that podocyte-derived Wnts play an important role in protecting podocytes from injury by repressing ß-catenin via activating non-canonical Wnt/calcium signaling.

The efficacy of pioglitazone for renal protection in diabetic kidney disease.

There is limited information on the efficacy of pioglitazone in diabetic kidney diseases (DKD). We evaluated whether pioglitazone exerts renal-protective effects in DKD patients. We designed a retrospective cohort study, which included 742 type 2 diabetes mellitus (T2DM) patients with DKD in Taiwan, with eGFR between 30 and 90 ml/min/1.73 m2 and UACR level 300-5000 mg/g. Patients not meeting the target range for HbA1c (above 7%) were given additional medication with pioglitazone (n = 111) or received standard care (non-pioglitazone group, n = 631). The primary endpoint was the occurrence of composite renal endpoints, which was defined as sustained eGFR<15 ml/min/1.73 m2 (confirmed by two measurements within 90 days); doubling of serum creatinine (compared to baseline); and the presence of hemodialysis or renal transplantation. The median follow-up duration was two years. At baseline, the mean HbA1C levels in the pioglitazone and non-pioglitazone groups were 8.8% and 8.1%, respectively; mean ages were 64.4 and 66.2 years old, respectively; diabetes durations were 14.3 and 12.3 years, respectively. Baseline eGFR showed no significant difference between the pioglitazone and non-pioglitazone groups (55.8 and 58.8 mL/min/1.73 m2, respectively). In terms of gender, 63% of patients were male in the pioglitazone group compared with 57% in the non-pioglitazone group. Pioglitazone use did not reduce the risk of composite renal endpoints in DKD patients (HR: 0.97, 95% CI = 0.53-1.77), including persistent eGFR<15 ml/min/1.73 m2 (HR = 1.07, 95% CI = 0.46-2.52), doubling of serum creatinine (HR = 0.97, 95% CI = 0.53-1.77), or ESRD (HR = 2.58, 95% CI = 0.29-23.04). The results were not changed after various adjustments. A non-significant albuminuria reduction was also noted after pioglitazone prescription in DKD patients. Further randomized controlled studies are needed to establish the effects of pioglitazone definitively.

Empagliflozin protects glomerular endothelial cell architecture in experimental diabetes through the VEGF-A/caveolin-1/PV-1 signaling pathway.

In addition to having blood glucose-lowering effects, inhibitors of sodium glucose cotransporter 2 (SGLT2) afford renoprotection in diabetes. We sought to investigate which components of the glomerular filtration barrier could be involved in the antiproteinuric and renoprotective effects of SGLT2 inhibition in diabetes. BTBR (black and tan, brachyuric) ob/ob mice that develop a type 2 diabetic nephropathy received a standard diet with or without empagliflozin for 10 weeks, starting at 8 weeks of age, when animals had developed albuminuria. Empagliflozin caused marked decreases in blood glucose levels and albuminuria but did not correct glomerular hyperfiltration. The protective effect of empagliflozin against albuminuria was not due to a reduction in podocyte damage as empagliflozin did not affect the larger podocyte filtration slit pore size nor the defective expression of nephrin and nestin. Empagliflozin did not reduce the thickening of the glomerular basement membrane. In BTBR ob/ob mice, the most profound abnormality seen using electron microscopy was in the endothelial aspect of the glomerular capillary, with significant loss of endothelial fenestrations. Remarkably, empagliflozin ameliorated the subverted microvascular endothelial ultrastructure. Caveolae and bridging diaphragms between adjacent endothelial fenestrae were seen in diabetic mice and associated with increased expression of caveolin-1 and the appearance of PV-1. These endothelial abnormalities were limited by the SGLT2 inhibitor. Although no expression of SGLT2 was found in glomerular endothelial cells, SGLT2 was expressed in the podocytes of diabetic mice. VEGF-A, which is a known stimulus for endothelial caveolin-1 and PV-1, was increased in podocytes of BTBR ob/ob mice and normalized by SGLT2 inhibitor treatment. Thus, empagliflozin's protective effect on the glomerular endothelium of diabetic mice could be due to a limitation of the paracrine signaling of podocyte-derived VEGF-A that resulted in a reduction of the abnormal endothelial caveolin-1 and PV-1, with the consequent preservation of glomerular endothelial function and permeability. © 2022 The Pathological Society of Great Britain and Ireland.

miR-193a as a potential mediator of WT-1/synaptopodin in the renoprotective effect of Losartan on diabetic kidney.

Diabetic nephropathy (DN) is the most common complication of diabetic patients, and has become a global healthcare problem. In this study, we used diabetic mice to evaluate the effect of Losartan on DN, in which the experimental animals were divided into three groups: non-diabetic mice (db/m group), untreated-diabetic mice (db/db group), and Losartan-treated diabetic mice (db/db-losartan). Next, immunohistochemistry and immunofluorescence were used to detect Wilms tumor protein 1 (WT-1) and synaptopodin expression, respectively. Protein levels of WT-1, synaptopodin, claudin1, and Pax-2 were assessed by Western blotting and real-time PCR. The miR-193a mRNA levels were quantitated by real-time PCR. The results showed that albuminuria was increased in diabetic mice compared with control animals and was significantly ameliorated by treatment with Losartan. In addition, Losartan significantly upregulated the immunopositive cell numbers of WT-1, the expression of WT-1 and synaptopodin in renal tissue. By contrast, expression of claudin1 and Pax-2 in renal tissue were decreased in db/db-losartan group. Besides, expression of miR-193a was decreased significantly in db/db-losartan group compared with the untreated diabetic group. Thus, Losartan has renoprotective effects on the control of tissue damage possibly by inhibiting the expression of miR-193a, thereby promoting the repair of podocyte injury in mice with DN.