Effect of thiazolidinediones on albuminuria and proteinuria in diabetes: a meta-analysis

Effect of preceding drug therapy on the renal and cardiovascular outcomes of combined sodium-glucose cotransporter-2 inhibitor and glucagon-like peptide-1 receptor agonist treatment in patients with type 2 diabetes and chronic kidney disease

AIM

To conduct a post hoc subgroup analysis of patients with type 2 diabetes (T2D) from the RECAP study, who were treated with sodium-glucose cotransporter-2 (SGLT2) inhibitor and glucagon-like peptide 1 receptor agonist (GLP-1RA) combination therapy, focusing only on those patients who had chronic kidney disease (CKD), to examine whether the composite renal outcome differed between those who received SGLT2 inhibitor treatment first and those who received a GLP-1RA first.

METHODS

We included 438 patients with CKD (GLP-1RA-first group, n = 223; SGLT2 inhibitor-first group, n = 215) from the 643 T2D patients in the RECAP study. The incidence of the composite renal outcome, defined as progression to macroalbuminuria and/or a ≥50% decrease in estimated glomerular filtration rate (eGFR), was analysed using a propensity score (PS)-matched model. Furthermore, we calculated the win ratio for these composite renal outcomes, which were weighted in the following order: (1) both a ≥50% decrease in eGFR and progression to macroalbuminuria; (2) a decrease in eGFR of ≥50% only; and (3) progression to macroalbuminuria only.

RESULTS

Using the PS-matched model, 132 patients from each group were paired. The incidence of renal composite outcomes did not differ between the two groups (GLP-1RA-first group, 10%; SGLT2 inhibitor-first group, 17%; odds ratio 1.80; 95% confidence interval [CI] 0.85 to 4.26; p = 0.12). The win ratio of the GLP-1RA-first group versus the SGLT2 inhibitor-first group was 1.83 (95% CI 1.71 to 1.95; p < 0.001).

CONCLUSION

Although the renal composite outcome did not differ between the two groups, the win ratio of the GLP-1RA-first group versus the SGLT2 inhibitor-first group was significant. These results suggest that, in GLP-1RA and SGLT2 inhibitor combination therapy, the addition of an SGLT2 inhibitor to baseline GLP-1RA treatment may lead to more favourable renal outcomes.

Insulin resistance before type 2 diabetes onset is associated with increased risk of albuminuria after diabetes onset: A prospective cohort study

AIM

Reduced renal insulin signalling is implicated in the pathogenesis of albuminuria. We sought to investigate whether insulin action and secretion, measured before diabetes onset, are associated with the development of albuminuria after diabetes onset.

MATERIALS AND METHODS

Baseline body composition, insulin sensitivity by hyperinsulinaemic-euglycaemic clamp at submaximal and maximal insulin stimulation (240 and 2400 pmol/m2/min; M-low and M-high), and insulin secretion by intravenous glucose tolerance test [acute insulin response (AIR)] were measured in 170 Southwestern Indigenous American adults who subsequently developed diabetes. After diabetes onset and during the median follow-up of 13.6 years, 81 participants (48%) developed albuminuria (urine albumin-to-creatinine ratio ≥30 mg/g). Separate associations of M-low, M-high and AIR (per 1-SD change) with the risk of albuminuria were assessed by Cox regression models adjusted for age, sex and body fat (%).

RESULTS

Participants who developed albuminuria were of similar age (26.4 ± 5.4 vs. 27.5 ± 6.1 years), sex (46% vs. 48% male), body fat (36.4 ± 7.5 vs. 35.7 ± 7.9%) and AIR [2.3 ± 0.3 vs. 2.3 ± 0.3, pmol/L (log)] as those who did not develop albuminuria but had lower insulin sensitivity [M-low: 0.33 ± 0.08 vs. 0.36 ± 0.12, p = .03; M-high: 0.87 ± 0.11 vs. 0.91 ± 0.12, p = .02; mg/kg-metabolic body size/min (log)]. In separate adjusted models, lower M-low and M-high were both associated with an increased risk for albuminuria [hazard ratio (HR) 1.51, 95% confidence interval (CI) 1.14, 2.00, p = .004; HR 1.31, 95% CI 1.06, 1.63, p = .01), whereas AIR was not (HR 1.15, 95% CI 0.87, 1.56, p = .3).

CONCLUSIONS

Lower insulin sensitivity is associated with the development of albuminuria, suggesting a role for insulin signalling in the pathogenesis of proteinuria.

Glucocorticoid- and pioglitazone-induced proteinuria reduction in experimental NS both correlate with glomerular ECM modulation

Idiopathic nephrotic syndrome (NS) is a common glomerular disease. Although glucocorticoids (GC) are the primary treatment, the PPARγ agonist pioglitazone (Pio) also reduces proteinuria in patients with NS and directly protects podocytes from injury. Because both drugs reduce proteinuria, we hypothesized these effects result from overlapping transcriptional patterns. Systems biology approaches compared glomerular transcriptomes from rats with PAN-induced NS treated with GC vs. Pio and identified 29 commonly regulated genes-of-interest, primarily involved in extracellular matrix (ECM) remodeling. Correlation with clinical idiopathic NS patient datasets confirmed glomerular ECM dysregulation as a potential mechanism of injury. Cellular deconvolution in silico revealed GC- and Pio-induced amelioration of altered genes primarily within podocytes and mesangial cells. While validation studies are indicated, these analyses identified molecular pathways involved in the early stages of NS (prior to scarring), suggesting that targeting glomerular ECM dysregulation may enable a future non-immunosuppressive approach for proteinuria reduction in idiopathic NS.

Pioglitazone, a PPAR-y agonist, as one of the new therapeutic candidates for C3 glomerulopathy

BACKGROUND

C3-glomerulopathy (C3G) is a rare pediatric kidney disease characterised by dysregulation of the alternative complement pathway, with glomerular deposition of C3. C3G may often present as a steroid-resistant nephrotic syndrome (SRNS), and there is no established effective therapy: the usual treatment involves corticosteroids and immunosuppressive drugs. Pioglitazone, a PPAR-γ agonist with a protective action on podocytes, was reported in a few cases as helpful in reducing proteinuria when combined with steroids.

CASE-DIAGNOSIS/TREATMENT

We report the case of a 13-year-old girl with silent past medical history who presented with SRNS. A kidney biopsy showed findings indicative of C3G. A low sodium diet and angiotensin-converting enzyme inhibitor were started; immunosuppressive treatment with mycophenolate mofetil (MMF) was administered due to the cortico-resistance. Because of poor response to the immunosuppressant, a trial with eculizumab was attempted without significant response and persistence of proteinuria in the nephrotic range. A further therapeutic trial was performed with tacrolimus with no disease remission. Due to a severe deterioration in her condition, the girl was hospitalized and treated with high-dose steroid bolus. A daily dose of oral prednisone and MMF were re-started without benefit with persistent levels of nephrotic range proteinuria. The administration of pioglitazone consistently lowered proteinuria levels for the first time since the onset of the disease, with a maintenance of the effect and normalization (< 0.15 g/24 h) at the 10-month follow-up.

CONCLUSIONS

In this patient affected by C3G, pioglitazone proved effective in reducing proteinuria levels.

Acute kidney injury in diabetic patients: A narrative review

Diabetes mellitus (DM) is the most common cause of chronic kidney disease, which leads to end-stage renal failure worldwide. Glomerular damage, renal arteriosclerosis, and atherosclerosis are the contributing factors in diabetic patients, leading to the progression of kidney damage. Diabetes is a distinct risk factor for acute kidney injury (AKI) and AKI is associated with faster advancement of renal disease in patients with diabetes. The long-term consequences of AKI include the development of end-stage renal disease, higher cardiovascular and cerebral events, poor quality of life, and high morbidity and mortality. In general, not many studies discussed extensively "AKI in DM." Moreover, articles addressing this topic are scarce. It is also important to know the cause of AKI in diabetic patients so that timely intervention and preventive strategies can be implemented to decrease kidney injury. Aim of this review article is to address the epidemiology of AKI, its risk factors, different pathophysiological mechanisms, how AKI differs between diabetic and nondiabetic patients and its preventive and therapeutic implications in diabetics. The increasing occurrence and prevalence of AKI and DM, as well as other pertinent issues, motivated us to address this topic.

Update on Diabetic Kidney Disease (DKD): Focus on Non-Albuminuric DKD and Cardiovascular Risk

The classic description of diabetic kidney disease (DKD) involves progressive stages of glomerular hyperfiltration, microalbuminuria, proteinuria, and a decline in the estimated glomerular filtration rate (eGFR), leading to dialysis. In recent years, this concept has been increasingly challenged as evidence suggests that DKD presents more heterogeneously. Large studies have revealed that eGFR decline may also occur independently from the development of albuminuria. This concept led to the identification of a new DKD phenotype: non-albuminuric DKD (eGFR < 60 mL/min/1.73 m², absence of albuminuria), whose pathogenesis is still unknown. However, various hypotheses have been formulated, the most likely of which is the acute kidney injury-to-chronic kidney disease (CKD) transition, with prevalent tubular, rather than glomerular, damage (typically described in albuminuric DKD). Moreover, it is still debated which phenotype is associated with a higher cardiovascular risk, due to contrasting results available in the literature. Finally, much evidence has accumulated on the various classes of drugs with beneficial effects on DKD; however, there is a lack of studies analyzing the different effects of drugs on the various phenotypes of DKD. For this reason, there are still no specific guidelines for therapy in one phenotype rather than the other, generically referring to diabetic patients with CKD.

Will lobeglitazone rival pioglitazone? A systematic review and critical appraisal

BACKGROUND AND AIMS

Lobeglitazone (LGZ), a newly researched thiazolidinedione (TZD) thought to have lesser side effects compared with pioglitazone (PGZ), has been recently approved for the treatment of type 2 diabetes (T2D) in India. We aim to conduct an updated systematic review of LGZ to critically appraise its efficacy and safety in the context of PGZ.

METHODS

A systematic literature search was carried out in the electronic database of PubMed until Jan 15, 2023, using specific keywords and MeSH terms. All studies which evaluated LGZ in people with T2D were retrieved and data were synthesized with regard to its efficacy and safety. A comparative critical appraisal was additionally made in the context of PGZ in T2D.

RESULTS

Four randomized controlled, one prospective observational, and two real-world studies have evaluated the safety and efficacy of LGZ against placebo or active comparators either as monotherapy or in combination therapy. HbA1c reduction with LGZ 0.5 mg was superior to the placebo but similar to PGZ 15 mg and sitagliptin (SITA) 100 mg. Weight gain with LGZ was significantly higher compared to placebo and SITA but similar to PGZ. Edema was more frequently observed with LGZ compared to placebo, PGZ, and SITA.

CONCLUSION

No substantial evidence is yet available that suggests LGZ could be a better alternative to PGZ both in the context of glycemic or extra-glycemic effects. At least in the short-term, adverse events of LGZ are indifferent from PGZ. More data is additionally needed to claim any advantage of LGZ over PGZ.

Pioglitazone enhances proteinuria reduction in complicated pediatric nephrotic syndrome

BACKGROUND

Nephrotic syndrome (NS) is a common pediatric kidney disease, yet current treatments for complicated NS are only partially effective and have significant toxicity. There is no Food and Drug Administration (FDA)- or European Medicines Agency (EMA)-approved safe and effective treatment for NS. Thiazolidinediones (TZDs) have been shown to reduce proteinuria in both diabetic and non-diabetic kidney disease and in preclinical studies to directly protect podocytes from injury and reduce proteinuria. Here, we report on the potential utility of the addition of the TZD pioglitazone (PIO) to enhance proteinuria reduction in 8 children and young adults with steroid dependent NS and steroid resistant NS.

METHODS

Clinical data were analyzed in comparable time periods before and after the addition of PIO to their medical regimens. Eight NS patients with minimal change NS (n = 2), focal segmental glomerulosclerosis (FSGS) (n = 4), or collapsing FSGS (n = 2) were evaluated.

RESULTS

Prior to PIO initiation, all children and young adults had already received multiple immunosuppressive medications (mean = 3.75). Five of eight patients (63%; "Responders") had notable proteinuria reduction within 1 month of PIO initiation (62% reduction; P = 0.04) and normalization within 6 months (97% reduction; P = 0.04). PIO-related benefits among the responders included notable increases in serum albumin (2.5 to 3.7 g/dl; P = 0.08), dramatic reductions in hospitalizations for IV albumin infusions and diuresis (11 to 0; P < 0.01), and considerable reduction in total immunosuppression (43% reduction; P > 0.1). Importantly, no patients experienced any adverse events attributable to PIO during a total of 136 patient-months of treatment.

CONCLUSIONS

While confirmatory safety and efficacy studies are needed, these findings suggest pioglitazone (a non-immunosuppressive drug) may be useful to enhance proteinuria reduction in some children and young adults with complicated NS. A higher resolution version of the Graphical abstract is available as Supplementary information.

Peroxisome proliferator-activated receptor ɣ agonist mediated inhibition of heparanase expression reduces proteinuria

BACKGROUND

Proteinuria is associated with many glomerular diseases and a risk factor for the progression to renal failure. We previously showed that heparanase (HPSE) is essential for the development of proteinuria, whereas peroxisome proliferator-activated receptor ɣ (PPARɣ) agonists can ameliorate proteinuria. Since a recent study showed that PPARɣ regulates HPSE expression in liver cancer cells, we hypothesized that PPARɣ agonists exert their reno-protective effect by inhibiting glomerular HPSE expression.

METHODS

Regulation of HPSE by PPARɣ was assessed in the adriamycin nephropathy rat model, and cultured glomerular endothelial cells and podocytes. Analyses included immunofluorescence staining, real-time PCR, heparanase activity assay and transendothelial albumin passage assay. Direct binding of PPARɣ to the HPSE promoter was evaluated by the luciferase reporter assay and chromatin immunoprecipitation assay. Furthermore, HPSE activity was assessed in 38 type 2 diabetes mellitus (T2DM) patients before and after 16/24 weeks treatment with the PPARɣ agonist pioglitazone.

FINDINGS

Adriamycin-exposed rats developed proteinuria, an increased cortical HPSE and decreased heparan sulfate (HS) expression, which was ameliorated by treatment with pioglitazone. In line, the PPARɣ antagonist GW9662 increased cortical HPSE and decreased HS expression, accompanied with proteinuria in healthy rats, as previously shown. In vitro, GW9662 induced HPSE expression in both endothelial cells and podocytes, and increased transendothelial albumin passage in a HPSE-dependent manner. Pioglitazone normalized HPSE expression in adriamycin-injured human endothelial cells and mouse podocytes, and adriamycin-induced transendothelial albumin passage was reduced as well. Importantly, we demonstrated a regulatory effect of PPARɣ on HPSE promoter activity and direct PPARy binding to the HPSE promoter region. Plasma HPSE activity of T2DM patients treated with pioglitazone for 16/24 weeks was related to their hemoglobin A1c and showed a moderate, near significant correlation with plasma creatinine levels.

INTERPRETATION

PPARɣ-mediated regulation of HPSE expression appears an additional mechanism explaining the anti-proteinuric and renoprotective effects of thiazolidinediones in clinical practice.

FUNDING

This study was financially supported by the Dutch Kidney Foundation, by grants 15OI36, 13OKS023 and 15OP13. Consortium grant LSHM16058-SGF (GLYCOTREAT; a collaboration project financed by the PPP allowance made available by Top Sector Life Sciences & Health to the Dutch Kidney Foundation to stimulate public-private partnerships).

The Mitochondrion: A Promising Target for Kidney Disease

Mitochondrial dysfunction is important in the pathogenesis of various kidney diseases and the mitochondria potentially serve as therapeutic targets necessitating further investigation. Alterations in mitochondrial biogenesis, imbalance between fusion and fission processes leading to mitochondrial fragmentation, oxidative stress, release of cytochrome c and mitochondrial DNA resulting in apoptosis, mitophagy, and defects in energy metabolism are the key pathophysiological mechanisms underlying the role of mitochondrial dysfunction in kidney diseases. Currently, various strategies target the mitochondria to improve kidney function and kidney treatment. The agents used in these strategies can be classified as biogenesis activators, fission inhibitors, antioxidants, mPTP inhibitors, and agents which enhance mitophagy and cardiolipin-protective drugs. Several glucose-lowering drugs, such as glucagon-like peptide-1 receptor agonists (GLP-1-RA) and sodium glucose co-transporter-2 (SGLT-2) inhibitors are also known to have influences on these mechanisms. In this review, we delineate the role of mitochondrial dysfunction in kidney disease, the current mitochondria-targeting treatment options affecting the kidneys and the future role of mitochondria in kidney pathology.

Effects of glucose-lowering agents on cardiovascular and renal outcomes in subjects with type 2 diabetes: An updated meta-analysis of randomized controlled trials with external adjudication of events

AIMS

To investigate the effects of glucose-lowering agents on all-cause mortality, and cardiovascular and renal outcomes in adults with type 2 diabetes.

METHODS

A MEDLINE and EMBASE search was performed to identify randomized controlled trials, published up to 28 February 2022, with a follow-up ≥52 weeks, in which glucose-lowering drugs were compared with either placebo or active comparators. We included only trials reporting formal external adjudication of events. All-cause mortality, 3-point MACE (major cardiovascular events), and hospitalization for heart failure (HHF) were considered as principal outcomes. Doubling of serum creatinine, worsening albuminuria, and renal death were considered as secondary endpoints.

RESULTS

We included randomized controlled trials performed on metformin (n = 17), pioglitazone (n = 20), alpha-glucosidase inhibitors (n = 9), insulin secretagogues (n = 42), dipeptidyl-peptidase-4 inhibitors (n = 67), glucagon-like peptide-1 receptor agonists (n = 45) or sodium-glucose co-transporter-2 inhibitors (SGLT-2i; n = 42) and insulin (n = 18). Glucagon-like peptide-1 receptor agonist and SGLT-2i were associated with a significant reduction in all-cause mortality [Mantel-Haenszel odds ratio (MH-OR), 95% confidence interval: 0.88 (0.83; 0.95) and 0.85 (0.79; 0.91), respectively] and MACE [MH-OR, 95% confidence interval: 0.89 (0.84; 0.94) and 0.90 (0.84; 0.96), respectively]. SGLT-2i was associated with a reduced risk of HHF [MH-OR 0.68 (0.62; 0.75)], worsening albuminuria [MH-OR 0.67 (0.55; 0.80)] and doubling of serum creatinine [MH-OR 0.58 (0.44; 0.79)]. Metformin and pioglitazone were associated with a significantly lower risk of MACE [MH-OR 0.60 (0.47; 0.80) and 0.85 (0.74; 0.97), respectively] and pioglitazone with a higher risk of HHF [MH-OR 1.30 (1.04; 1.62)]. Insulin secretagogues were associated with increased risk of all-cause mortality [MH-OR 1.12 (1.01; 1.24)] and MACE [MH-OR 1.19 (1.02; 1.39)].

CONCLUSIONS

The results of this updated meta-analysis need to be considered in the choice of drug treatment for type 2 diabetes mellitus, which cannot be merely based on the effect of glucose-lowering drugs on long-term glycaemic control.

Pharmacotherapy of type 2 diabetes: An update and future directions

Type 2 diabetes (T2D) is a widely prevalent disease with substantial economic and social impact for which multiple conventional and novel pharmacotherapies are currently available; however, the landscape of T2D treatment is constantly changing as new therapies emerge and the understanding of currently available agents deepens. This review aims to provide an updated summary of the pharmacotherapeutic approach to T2D. Each class of agents is presented by mechanism of action, details of administration, side effect profile, cost, and use in certain populations including heart failure, non-alcoholic fatty liver disease, obesity, chronic kidney disease, and older individuals. We also review targets of novel therapeutic T2D agent development. Finally, we outline an up-to-date treatment approach that starts with identification of an individualized goal for glycemic control then selection, initiation, and further intensification of a personalized therapeutic plan for T2D.

Alternatively Spliced Landscape of PPARγ mRNA in Podocytes Is Distinct from Adipose Tissue

Podocytes are highly differentiated epithelial cells, and their structural and functional integrity is compromised in a majority of glomerular and renal diseases, leading to proteinuria, chronic kidney disease, and kidney failure. Traditional agonists (e.g., pioglitazone) and selective modulators (e.g., GQ-16) of peroxisome-proliferator-activated-receptor-γ (PPARγ) reduce proteinuria in animal models of glomerular disease and protect podocytes from injury via PPARγ activation. This indicates a pivotal role for PPARγ in maintaining glomerular function through preservation of podocytes distinct from its well-understood role in driving insulin sensitivity and adipogenesis. While its transcriptional role in activating adipokines and adipogenic genes is well-established in adipose tissue, liver and muscle, understanding of podocyte PPARγ signaling remains limited. We performed a comprehensive analysis of PPARγ mRNA variants due to alternative splicing, in human podocytes and compared with adipose tissue. We found that podocytes express the ubiquitous PPARγ Var 1 (encoding γ1) and not Var2 (encoding γ2), which is mostly restricted to adipose tissue and liver. Additionally, we detected expression at very low level of Var4, and barely detectable levels of other variants, Var3, Var11, VartORF4 and Var9, in podocytes. Furthermore, a distinct podocyte vs. adipocyte PPAR-promoter-response-element containing gene expression, enrichment and pathway signature was observed, suggesting differential regulation by podocyte specific PPARγ1 variant, distinct from the adipocyte-specific γ2 variant. In summary, podocytes and glomeruli express several PPARγ variants, including Var1 (γ1) and excluding adipocyte-specific Var2 (γ2), which may have implications in podocyte specific signaling and pathophysiology. This suggests that that new selective PPARγ modulators can be potentially developed that will be able to distinguish between the two forms, γ1 and γ2, thus forming a basis of novel targeted therapeutic avenues.

Renal insulin resistance in type 2 diabetes mellitus and progression of chronic kidney disease: potential pathogenic mechanisms

INTRODUCTION

A bidirectional association exists between insulin resistance (IR) and chronic kidney disease (CKD) in Type 2 Diabetes Mellitus (T2DM). Baseline measures of IR are predictive of CKD progression, and uremia in progressive CKD is itself, in turn, associated with a worsening of IR. Pre-clinical research reveals that intrinsic IR in glomerular podocytes and the renal tubule may serve as a pathogenic driver of CKD in T2DM.

AREAS COVERED

The present manuscript takes as its point of departure, the recently identified prognostic utility of severe insulin resistance as a predictor of CKD in T2DM. Findings from a series of studies describing the association of IR with pathological alterations in both established, and less commonly assessed dynamic measures of renal impairment are discussed. Drawing upon the pre-clinical mechanistic evidence base, the cellular and molecular basis of intrinsic renal IR as a promoter of CKD is considered.

EXPERT OPINION

Measurement of insulin sensitivity may add value to profiling of renal risk in T2DM. Rational selection of therapeutic strategies targeting the enhancement of insulin sensitivity merits special attention regarding the personalized management of CKD in insulin resistance predominant T2DM.

Obesity-related glomerulopathy: Current approaches and future perspectives

Obesity-related glomerulopathy (ORG) is a silent comorbidity which is increasing in incidence as the obesity epidemic escalates. ORG is associated with serious health consequences including chronic kidney disease, end-stage renal disease (ESRD), and increased mortality. Although the pathogenic mechanisms involved in the development of ORG are not fully understood, glomerular hemodynamic changes, renin-angiotensin-aldosterone system (RAAS) overactivation, insulin-resistance, inflammation and ectopic lipid accumulation seem to play a major role. Despite albuminuria being commonly used for the non-invasive evaluation of ORG, promising biomarkers of early kidney injury that are emerging, as well as new approaches with proteomics and metabolomics, might permit an earlier diagnosis of this disease. In addition, the assessment of ectopic kidney fat by renal imaging could be a useful tool to detect and evaluate the progression of ORG. Weight loss interventions appear to be effective in ORG, although large-scale trials are needed. RAAS blockade has a renoprotective effect in patients with ORG, but even so, a significant proportion of patients with ORG will eventually progress to ESRD despite therapeutic efforts. It is noteworthy that certain antidiabetic agents such as sodium-glucose cotransporter 2 inhibitors (SGLT2i) or glucagon-like peptide-1 receptor agonists (GLP-1 RAs) could be useful in the treatment of ORG through different pleiotropic effects. In this article, we review current approaches and future perspectives in the care and treatment of ORG.

Extra-Glycemic Effects of Anti-Diabetic Medications: Two Birds with One Stone?

The world is suffering from a rapid increase in the number of people with diabetes due to the increased prevalence of obesity and lengthened life span. Since the development of insulin thanks to the efforts of Prof. Banting and Dr. Best in 1922, for which they won the Nobel Prize, remarkable developments in anti-diabetic medications have dramatically lengthened the lifespan of patients with diabetes. However, the control rate of hyperglycemia in patients with diabetes remains unsatisfactory, since glycemic control requires both medication and lifestyle modifications to slow the deterioration of pancreatic beta-cell function and prevent diabetic complications. From the initial "triumvirate" to the "ominous octet," and now the "egregious eleven," the number of organs recognized as being involved in hyperglycemia and diabetes has increased with the development of anti-diabetic medications. Recent unexpected results from outcome trials of anti-diabetic medications have enabled anti-diabetic medications to be indicated for the prevention of chronic kidney disease and heart failure, even in patients without diabetes. In this review, I would like to summarize the extra-glycemic effects of anti-diabetic medications.

Selective modulator of nuclear receptor PPARγ with reduced adipogenic potential ameliorates experimental nephrotic syndrome

Glomerular disease manifests as nephrotic syndrome (NS) with high proteinuria and comorbidities, and is frequently refractory to standard treatments. We hypothesized that a selective modulator of PPARγ, GQ-16, will provide therapeutic advantage over traditional PPARγ agonists for NS treatment. We demonstrate in a pre-clinical NS model that proteinuria is reduced with pioglitazone to 64%, and robustly with GQ-16 to 81% of nephrosis, comparable to controls. Although both GQ-16 and pioglitazone restore glomerular-Nphs1, hepatic-Pcsk9 and serum-cholesterol, only GQ-16 restores glomerular-Nrf2, and reduces hypoalbuminemia and hypercoagulopathy. GQ-16 and pioglitazone restore common and distinct glomerular gene expression analyzed by RNA-seq and induce insulin sensitizing adipokines to various degrees. Pioglitazone but not GQ-16 induces more lipid accumulation and aP2 in adipocytes and white adipose tissue. We conclude that selective modulation of PPARγ by a partial agonist, GQ-16, is more advantageous than pioglitazone in reducing proteinuria, NS associated comorbidities, and adipogenic side effects of full PPARγ agonists.

Pioglitazone, Bladder Cancer and the Presumption of Innocence

BACKGROUND

Thiazolidinediones are potent exogenous agonists of PPAR-γ, which augment the effects of insulin to its cellular targets and mainly at the level of adipose tissue. Pioglitazone, the main thiazolidinedione in clinical practice, has shown cardiovascular and renal benefits in patients with type 2 diabetes, durable reduction of glycated hemoglobulin levels, important improvements of several components of the metabolic syndrome and beneficial effects of non-alcoholic fatty liver disease.

OBJECTIVE

Despite all of its established advantages, the controversy for an increased risk of developing bladder cancer, combined with the advent of newer drug classes that achieved major cardiorenal effects have significantly limited its use spreading a persistent shadow of doubt for its future role.

METHODS

Pubmed, Google and Scope databases have been thoroughly searched and relevant studies were selected.

RESULTS

This paper explores thoroughly both in vitro and in vivo (animal models and humans) studies that investigated the possible association of pioglitazone with bladder cancer.

CONCLUSION

Currently the association of pioglitazone with bladder cancer cannot be based on solid evidence. This evidence cannot justify its low clinical administration, especially in the present era of individualised treatment strategies. Definite clarification of this issue is imperative and urgently anticipated from future high quality and rigorous pharmacoepidemiologic research, keeping in mind its unique mechanism of action and its significant pleiotropic effects.

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.

Drug Therapies Affecting Renal Function: An Overview

Undesirable side effects of medication are inevitable. Due to the role of the kidneys in clearance and filtration, the renal system faces a unique situation when it comes to the side effects of drugs. It has an important role for different classes of drugs to be excreted, and drugs are a key factor for this system to be at risk. Medications in articles were divided into classes using the standard set by the Saudi Pharmaceutical Journal. Many drug classes cause renal insults. The top six classes were pain killers, antibiotics, proton pump inhibitors, antidiabetics, antihyperlipidemics, and agents for erectile dysfunction. Renal insults caused by these agents could vary in severity. Some drugs could cause nephrotoxicity from one dose, while others may only need continuous monitoring. Different populations also operate under different rules, as some people need dose adjustments while others who are medically free of major illnesses do not. A variety of unfavorable outcomes for the kidney could take place, such as acute kidney injury, chronic kidney disease, and end-stage renal disease, and unfortunately, some of these issues could lead to the need for renal replacement therapies. The outcome of this review paper will help multidisciplinary physicians to understand the renal side effects of the most used drug classes in the Kingdom of Saudi Arabia, their destructive mechanisms, and most importantly, the clinical presentations of renal dysfunction in relation to each class. Emphasizing these adverse effects will prevent future unfavorable outcomes, especially in commonly used drugs that are frequently prescribed for different age groups. Moreover, some of these drugs are considered to be over-the-counter medications, which makes them a serious problem that needs to be handled cautiously.

PPARγ and TGFβ-Major Regulators of Metabolism, Inflammation, and Fibrosis in the Lungs and Kidneys

Peroxisome proliferator-activated receptor gamma (PPARγ) is a type II nuclear receptor, initially recognized in adipose tissue for its role in fatty acid storage and glucose metabolism. It promotes lipid uptake and adipogenesis by increasing insulin sensitivity and adiponectin release. Later, PPARγ was implicated in cardiac development and in critical conditions such as pulmonary arterial hypertension (PAH) and kidney failure. Recently, a cluster of different papers linked PPARγ signaling with another superfamily, the transforming growth factor beta (TGFβ), and its receptors, all of which play a major role in PAH and kidney failure. TGFβ is a multifunctional cytokine that drives inflammation, fibrosis, and cell differentiation while PPARγ activation reverses these adverse events in many models. Such opposite biological effects emphasize the delicate balance and complex crosstalk between PPARγ and TGFβ. Based on solid experimental and clinical evidence, the present review summarizes connections and their implications for PAH and kidney failure, highlighting the similarities and differences between lung and kidney mechanisms as well as discussing the therapeutic potential of PPARγ agonist pioglitazone.

Mitochondrial DNA may act as a biomarker to predict donor-kidney quality

Kidney transplantation is the best therapy for end-stage renal disease. Demand for kidney transplantation rises year-on-year, and the gap between kidney supply and demand remains large. To meet this clinical need, a gradual expansion in the supply of donors is required. However, clinics lack appropriate tools capable of quickly and accurately predicting post-transplant renal allograft function, and thus assess donor-kidney quality before transplantation. Mitochondrial DNA (mtDNA) is a key component of damage-associated molecular patterns (DAMPs) and plays an important part in ischemia-reperfusion injury (IRI), accelerating the progression of IRI by inducing inflammation and type I interferon responses. mtDNA is known to be closely involved in delayed graft function (DGF) and acute kidney injury (AKI) after transplantation. Thus, mtDNA is a potential biomarker able to predict post-transplant renal allograft function. This review summarizes mtDNA biology, the role mtDNA plays in renal transplantation, outlines advances in detecting mtDNA, and details mtDNA's able to predict post-transplant renal allograft function. We aim to elucidate the potential value of mtDNA as a biomarker in the prediction of IRI, and eventually provide help for predicting donor-kidney quality.

Chiglitazar monotherapy with sitagliptin as an active comparator in patients with type 2 diabetes: a randomized, double-blind, phase 3 trial (CMAS)

Chiglitazar (Carfloglitazar) is a novel peroxisome proliferator-activated receptor (PPAR) pan-agonist that has shown promising effects on glycemic control and lipid regulation in patients with type 2 diabetes. In this randomized phase 3 trial, we compared the efficacy and safety of chiglitazar with sitagliptin in patients with type 2 diabetes who had insufficient glycemic control despite a strict diet and exercise regimen. Eligible patients were randomized (1:1:1) to receive chiglitazar 32 mg (n = 245), chiglitazar 48 mg (n = 246), or sitagliptin 100 mg (n = 248) once daily for 24 weeks. The primary endpoint was the change in glycosylated hemoglobin A_1C (HbA_1c) from baseline at week 24 with the non-inferiority of chiglitazar over sitagliptin. Both chiglitazar and sitagliptin significantly reduced HbA_1c at week 24 with values of -1.40%, -1.47%, and -1.39% for chiglitazar 32 mg, chiglitazar 48 mg, and sitagliptin 100 mg, respectively. Chiglitazar 32 and 48 mg were both non-inferior to sitagliptin 100 mg, with mean differences of -0.04% (95% confidential interval (CI) -0.22 to 0.15) and -0.08% (95% CI -0.27 to 0.10), respectively. Compared with sitagliptin, greater reduction in fasting and 2-h postprandial plasma glucose and fasting insulin was observed with chiglitazar. Overall adverse event rates were similar between the groups. A small increase in mild edema in the chiglitazar 48 mg group and slight weight gain in both chiglitazar groups were reported. The overall results demonstrated that chiglitazar possesses good efficacy and safety profile in patients with type 2 diabetes inadequately controlled with lifestyle interventions, thereby providing adequate supporting evidence for using this PPAR pan-agonist as a treatment option for type 2 diabetes.

Combining glomerular basement membrane and tubular basement membrane assessment improves the prediction of diabetic end-stage renal disease

BACKGROUND

To address the prognostic value of combining tubular basement membrane (TBM) and glomerular basement membrane (GBM) thickness in diabetic nephropathy (DN).

METHODS

This retrospective study enrolled 110 patients with type 2 diabetes and biopsy-proven DN from 2011 to 2018. The pathological findings were confirmed according to the Renal Pathology Society classifications. GBM and TBM thicknesses were determined using the Haas' direct measurement/arithmetic mean method and orthogonal intercept method, respectively. Cox proportional hazard models were used to investigate the hazard ratios (HRs) for the influence of combined GBM and TBM thickness for predicting end-stage renal disease (ESRD).

RESULTS

Patients were assigned to three groups according to the median GBM and TBM thickness: GBM^lo TBM^lo (GBM < 681 nm and TBM < 1200 nm), GBM^hi TBM^lo /GBM^lo TBM^hi (GBM ≥ 681 nm and TBM < 1200 nm, or GBM < 681 nm and TBM ≥ 1200 nm), and GBM^hi TBM^hi (GBM ≥ 681 nm and TBM ≥ 1200 nm). The GBM^hi TBM^lo /GBM^lo TBM^hi and GBM^hi TBM^hi groups displayed poorer renal function, a more severe glomerular classification and interstitial inflammation, and poorer renal survival rates than the GBM^lo TBM^lo group The GBM^hi TBM^lo /GBM^lo TBM^hi and GBM^hi TBM^hi groups had adjusted HRs of 1.49 (95% confidence interval [CI], 1.21-9.75) and 3.07 (95% CI, 2.87-12.78), respectively, compared with the GBM^lo TBM^lo group.

CONCLUSIONS

TBM thickness enhanced GBM thickness for renal prognosis in patients with type 2 diabetes.

Sodium--glucose co-transporter-2 inhibitors for patients with diabetic and nondiabetic chronic kidney disease: a new era has already begun

Chronic kidney disease (CKD) is a major issue of public health. Hypertension control and use of renin--angiotensin system (RAS) blockers are the cornerstones of treatment for CKD of any cause. However, even under optimal RAS blockade, many individuals will progress towards more advanced CKD. Within the past few years, evidence from cardiovascular outcome trials with sodium--glucose co-transporter-2 (SGLT-2) inhibitors clearly suggested that these agents substantially delay CKD progression in patients with diabetes mellitus on top of standard-of-care treatment. The Canagliflozin-and-Renal-Events-in-Diabetes-with-Established-Nephropathy-Clinical-Evaluation (CREDENCE) study, showed that canagliflozin substantially reduced the risk of doubling of SCr, end-stage kidney disease (ESKD), or death from renal or cardiovascular causes in 4401 patients with diabetic CKD compared with placebo (hazard ratio 0.70; 95% CI 0.59-0.82). Recently, the Study-to-Evaluate-the-Effect-of-Dapagliflozin-on-Renal-Outcomes-and-Cardiovascular-Mortality-in-Patients-With-Chronic-Kidney-Disease (DAPA-CKD), including 2510 patients with diabetic and 1803 with nondiabetic CKD, also showed an impressive reduction in the risk of ≥50% decline in eGFR, ESKD, or death from renal or cardiovascular causes (HR 0.61; 95% CI 0.51-0.72). The benefit was similar for patients with diabetic and nondiabetic CKD, including patients with glomerulonephritides. Following this conclusive evidence, relevant guidelines should accommodate their recommendations to implement treatment with SGLT-2 inhibitors for patients with diabetic and nondiabetic CKD.

Renal gluconeogenesis in insulin resistance: A culprit for hyperglycemia in diabetes

Renal gluconeogenesis is one of the major pathways for endogenous glucose production. Impairment in this process may contribute to hyperglycemia in cases with insulin resistance and diabetes. We reviewed pertinent studies to elucidate the role of renal gluconeogenesis regulation in insulin resistance and diabetes. A consensus on the suppressive effect of insulin on kidney gluconeogenesis has started to build up. Insulin-resistant models exhibit reduced insulin receptor (IR) expression and/or post-receptor signaling in their kidney tissue. Reduced IR expression or post-receptor signaling can cause impairment in insulin’s action on kidneys, which may increase renal gluconeogenesis in the state of insulin resistance. It is now established that the kidney contributes up to 20% of all glucose production via gluconeogenesis in the post-absorptive phase. However, the rate of renal glucose release excessively increases in diabetes. The rise in renal glucose release in diabetes may contribute to fasting hyperglycemia and increased postprandial glucose levels. Enhanced glucose release by the kidneys and renal expression of the gluconeogenic-enzyme in diabetic rodents and humans further point towards the significance of renal gluconeogenesis. Overall, the available literature suggests that impairment in renal gluconeogenesis in an insulin-resistant state may contribute to hyperglycemia in type 2 diabetes.

Mitochondrial quality control in kidney injury and repair

Mitochondria are essential for the activity, function and viability of eukaryotic cells and mitochondrial dysfunction is involved in the pathogenesis of acute kidney injury (AKI) and chronic kidney disease, as well as in abnormal kidney repair after AKI. Multiple quality control mechanisms, including antioxidant defence, protein quality control, mitochondrial DNA repair, mitochondrial dynamics, mitophagy and mitochondrial biogenesis, have evolved to preserve mitochondrial homeostasis under physiological and pathological conditions. Loss of these mechanisms may induce mitochondrial damage and dysfunction, leading to cell death, tissue injury and, potentially, organ failure. Accumulating evidence suggests a role of disturbances in mitochondrial quality control in the pathogenesis of AKI, incomplete or maladaptive kidney repair and chronic kidney disease. Moreover, specific interventions that target mitochondrial quality control mechanisms to preserve and restore mitochondrial function have emerged as promising therapeutic strategies to prevent and treat kidney injury and accelerate kidney repair. However, clinical translation of these findings is challenging owing to potential adverse effects, unclear mechanisms of action and a lack of knowledge of the specific roles and regulation of mitochondrial quality control mechanisms in kidney resident and circulating cell types during injury and repair of the kidney.

The impact of diabetes on heart failure development: The cardio-renal-metabolic connection

Heart failure (HF) and chronic kidney disease (CKD) are often associated in type 2 diabetes (T2D), aggravate each other and exert synergistic effects to increase the risk of cardiac and renal events. The risks of renal worsening in HF patients and HF in CKD patients need to be evaluated to tailor preventive therapy. The recent CV and renal trials enriched our knowledge about the natural history of HF and CKD in T2D and provided evidence for the benefit of sodium-glucose cotransporter 2 inhibitors (SGLT2is) in HF and renal decline prevention. SGLT-2is are the best choice in patients with HFrEF to improve CV prognosis and HF-related outcomes and also to prevent kidney-related outcomes, and in CKD patients to slow down renal failure and also reduce hospitalization for HF and CV death. In both situations the number of patients to treat in order to prevent such events in one patient is lower than in the general T2D population at high CV risk. GLP1-receptor agonists could be an alternative in a patient who is intolerant or has a contraindication to SGLT-2is. A tight collaboration between diabetologists, nephrologists and cardiologists should be encouraged for a holistic and effective strategy to reduce the burden of cardio-renal-metabolic interaction.

Design, synthesis, and biological evaluation of a novel dual peroxisome proliferator-activated receptor alpha/delta agonist for the treatment of diabetic kidney disease through anti-inflammatory mechanisms

Diabetic kidney disease (DKD) is a major feature of the final stage of nearly all cause types of diabetes mellitus (DM). To date, few safe and effective drugs are available to treat. Peroxisome proliferator-activated receptors (PPARs), comprised of three members: PPAR-α, PPAR-δ and PPAR-γ, play a protective role in the DKD through glycemic control and lipid metabolism, whereas systemic activation of PPAR-γ causes serious side-effects in clinical trials. GFT505 is a dual PPAR-α/δ agonist, and the selectivity against PPAR-γ is still to be improved. Sulfuretin has been shown to suppress the expression of PPAR-γ and improve the pathogenesis of diabetic complications. In this study, by hybridizing the carboxylic acid of GFT505 and the parent nucleus of sulfuretin, we pioneeringly designed and synthetized a series of novel dual PPAR-α/δ agonists, expecting to provide a better benefit/risk ratio for PPARs. Of all the synthesized compounds, compound 12 was identified with highly activity on PPAR-α/δ and higher selectivity against PPAR-γ than that of GFT505 (EC₅₀: hPPAR-α: 0.26 μM vs.0.76 μM; hPPAR-δ: 0.50 μM vs.0.73 μM; hPPAR-γ: 4.22 μM vs.2.79 μM). The molecular docking studies also depicted good binding affinity of compound 12 for PPAR-α and PPAR-δ compared to GFT505. Furthermore, compound 12 exhibited an evidently renoprotective effect on the DKD through inhibiting inflammatory process, which might at least partly via JNK/NF-κB pathways in vivo and in vitro. Overall, compound 12 hold therapeutic promise for DKD.

Nephrotic range proteinuria associated with focal segmental glomerulosclerosis reversed with pioglitazone therapy in a patient with Dunnigan type lipodystrophy

Familial partiallipodystrophy (FPLD)is a rare disorder associated withsevere insulin resistance, hypertriglyceridemia, lowserumHDLcholesterol and proteinuricrenaldisease. Although proteinuric renal disease is not common among in patients with partial lipodystrophy, we report a patient with Dunnigan type FPLD complicated by nephrotic syndrome which resolved following treatment with thePPARγagonist pioglitazone, CPAP, diet, and exercise.

Acute Kidney Injury in Pediatric Diabetic Kidney Disease

Diabetic kidney disease (DKD) is a common complication of type 1 and 2 diabetes and often presents during adolescence and young adulthood. Given the growing incidence of both type 1 and type 2 diabetes in children and adolescents, DKD represents a significant public health problem. Acute kidney injury (AKI) in youth with diabetes is strongly associated with risk of DKD development. This review will summarize the epidemiology and pathophysiology of AKI in children with diabetes, the relationship between AKI and DKD, and the potential therapeutic interventions. Finally, we will appraise the impact of the recent COVID-19 infection pandemic on AKI in children with diabetes.

Genetics and Clinical Characteristics of PPARγ Variant-Induced Diabetes in a Chinese Han Population

OBJECTIVES

PPARγ variants cause lipodystrophy, insulin resistance, and diabetes. This study aimed to determine the relationship between PPARγ genotypes and phenotypes and to explore the pathogenesis of diabetes beyond this relationship.

METHODS

PPARγ2 exons in 1,002 Chinese patients with early-onset type 2 diabetes (diagnosed before 40 years of age) were sequenced. The functions of variants were evaluated by in vitro assays. Additionally, a review of the literature was performed to obtain all reported cases with rare PPARγ2 variants to evaluate the characteristics of variants in different functional domains.

RESULTS

Six (0.6%) patients had PPARγ2 variant-induced diabetes (PPARG-DM) in the early-onset type 2 diabetes group, including three with the p.Tyr95Cys variant in activation function 1 domain (AF1), of which five patients (83%) had diabetic kidney disease (DKD). Functional experiments showed that p.Tyr95Cys suppresses 3T3-L1 preadipocyte differentiation. A total of 64 cases with damaging rare variants were reported previously. Patients with rare PPARγ2 variants in AF1 of PPARγ2 had a lower risk of lipodystrophy and a higher rate of obesity than those with variants in other domains, as confirmed in patients identified in this study.

CONCLUSION

The prevalence of PPARG-DM is similar in Caucasian and Chinese populations, and DKD was often observed in these patients. Patients with variants in the AF1 of PPARγ2 had milder clinical phenotypes and lack typical lipodystrophy features than those with variants in other domains. Our findings emphasize the importance of screening such patients via genetic testing and suggest that thiazolidinediones might be a good choice for these patients.

Comparative Efficacy of Lobeglitazone Versus Pioglitazone on Albuminuria in Patients with Type 2 Diabetes Mellitus

INTRODUCTION

The aim of this analysis was to evaluate the efficacy of lobeglitazone on albuminuria at 24 weeks of follow-up in patients with type 2 diabetes mellitus (T2DM) compared with pioglitazone using data from a randomized, double-blinded phase III trial.

METHODS

In the phase III trial, patients who were inadequately controlled with metformin received 0.5 mg of lobeglitazone or 15 mg of pioglitazone for 24 weeks. Post hoc, exploratory analysis was used to investigate mean changes from baseline in the urine albumin-creatinine ratio (UACR) between the lobeglitazone (N = 104) and pioglitazone (N = 101) treatment groups.

RESULTS

After 24 weeks of treatment, UACR was slightly decreased in the lobeglitazone group (- 4.3 mg/g creatinine [Cr]) compared to baseline and slightly increased in the pioglitazone group (5.2 mg/g Cr), with no change in the estimated glomerular filtration rate in either group; this difference was not statistically significant (P = 0.476). The incidence of new-onset microalbuminuria (2.4%) and the progression of albuminuria by > 1 stage (2.9%) in the lobeglitazone group were lower than the respective values in the pioglitazone group (6.8 and 6.1%, respectively). Of the patients in the lobeglitazone group, 50% exhibited regression to normoalbuminuria, compared to 39.3% of the patients in the pioglitazone. In subjects in the lobeglitazone group with micro- and macroalbuminuria, UACR tended to be more decreased and HbA1c was more reduced compared to those with normoalbuminuria (P = 0.014).

CONCLUSION

Lobeglitazone had a tendency to improve albuminuria in patients with T2DM and had comparable effects on albuminuria as pioglitazone which has demonstrated beneficial effects.

TRIAL REGISTRATION

ClinicalTrials.gov identifier, NCT01106131.

Multi-conformational frame from molecular dynamics as a structure-based pharmacophore model for mapping, screening and identifying ligands against PPAR-γ: a new protocol to develop promising candidates

Despite intensive research on clinical and molecular factors, the development of antidiabetic drugs in the last few decades is decelerating and as a result, the number of drugs approved by the US FDA is reduced. Hence, there is a persistent need for the innovative development of novel anti-diabetic drugs. Recent studies have provided ample proof that the peroxisome proliferator-activated receptor gamma (PPARγ), a ligand-activated transcription factor and its co-activator PGC-1 alpha may serve as good candidates for the treatment of several metabolic disorders. Therefore, in this study, 50 ns molecular dynamics (MD) simulations of the ligand-receptor complex were carried out and the most populated cluster of rosiglitazone bound to crucial amino acids during dynamics studies were selected to generate multi-conformation frame and further dynamic pharmacophore models. Finally, three pharmacophore models were generated, and 10 hits were retrieved as final lead candidates by virtual screening of ZINC database and molecular docking. The study reveals that the amino acids Met364, Lys367, His449, Leu453, Leu469, and Tyr473 play a crucial role in the binding of the compounds at the active site of PPARγ and the selected compounds from the ZINC database showed promising binding as compared to rosiglitazone. Further, ADMET studies were carried out to define the pharmacokinetic properties of promising PPARγ ligand candidates.Communicated by Ramaswamy H. Sarma.

Nuclear receptors in podocyte biology and glomerular disease

Nuclear receptors have a broad spectrum of biological functions in normal physiology and in the pathology of various diseases, including glomerular disease. The primary therapies for many glomerular diseases are glucocorticoids, which exert their immunosuppressive and direct podocyte protective effects via the glucocorticoid receptor (GR). As glucocorticoids are associated with important adverse effects and a substantial proportion of patients show resistance to these therapies, the beneficial effects of selective GR modulators are now being explored. Peroxisome proliferator-activated receptor-γ (PPARγ) agonism using thiazolidinediones has potent podocyte cytoprotective and nephroprotective effects. Repurposing of thiazolidinediones or identification of novel PPARγ modulators are potential strategies to treat non-diabetic glomerular disease. Retinoic acid receptor-α is the key mediator of the renal protective effects of retinoic acid, and repair of the endogenous retinoic acid pathway offers another potential therapeutic strategy for glomerular disease. Vitamin D receptor, oestrogen receptor and mineralocorticoid receptor modulators regulate podocyte injury in experimental models. Further studies are needed to better understand the mechanisms of these nuclear receptors, evaluate their synergistic pathways and identify their novel modulators. Here, we focus on the role of nuclear receptors in podocyte biology and non-diabetic glomerular disease.

Insulin: Trigger and Target of Renal Functions

Kidney function in metabolism is often underestimated. Although the word “clearance” is associated to “degradation”, at nephron level, proper balance between what is truly degraded and what is redirected to de novo utilization is crucial for the maintenance of electrolytic and acid–basic balance and energy conservation. Insulin is probably one of the best examples of how diverse and heterogeneous kidney response can be. Kidney has a primary role in the degradation of insulin released in the bloodstream, but it is also incredibly susceptible to insulin action throughout the nephron. Fluctuations in insulin levels during fast and fed state add another layer of complexity in the understanding of kidney fine-tuning. This review aims at revisiting renal insulin actions and clearance and to address the association of kidney dysmetabolism with hyperinsulinemia and insulin resistance, both highly prevalent phenomena in modern society.

Association between Pro12Ala polymorphism and albuminuria in type 2 diabetic nephropathy

AIMS/INTRODUCTION

Diabetic nephropathy (DN) is a complication of diabetes mellitus that is characterized by the gradual loss of kidney function, which results in increased levels of albumin in the urine. The Pro12Ala polymorphism in the peroxisome proliferator-activated receptor-γ2 gene has been confirmed to improve insulin sensitivity, but its association with susceptibility to DN in patients with type 2 diabetes remains inconclusive.

MATERIALS AND METHODS

To examine whether the Pro12Ala polymorphism leads to the development of DN, a case-control study was carried out in 554 patients with type 2 diabetes. The genotypes of Pro12Ala polymorphism of the peroxisome proliferator-activated receptor gamma 2 gene were analyzed by real-time polymerase chain reaction with TaqMan® probe genotyping assay in all patients.

RESULTS

The mean age of the study population was 57.7 ± 8.8 years, with average diabetes duration of 12.8 ± 6.9 years. The prevalence of albuminuria was 43.5%. The frequency of genotype Pro12Pro, Pro12Ala and Ala12Ala genotype were 92.6%, 7.0%, 0.4% in our study population, and 90.4%, 8.9% and 0.7% in normal urinary albumin-to-creatinine ratio group, respectively. The Ala carriers (Pro12Ala + Ala12Ala) had significantly lower urinary albumin-to-creatinine ratio (15.0 vs 20.5 mg/g, P = 0.001) and better renal function (estimated glomerular filtration rate 81.8 [69.8-97.6] vs 78.7 mL/min/1.73 m2 [61.6-96.2]; P = 0.05) compared with those with the genotype Pro12Pro. After adjustment for age, sex and other confounders, the odds ratio of albuminuria for the Ala12 allele was 0.428 (95% confidence interval 0.195-0.940, P = 0.034]).

CONCLUSIONS

Our results suggest that the peroxisome proliferator-activated receptor gamma 2 Ala12 variant has significant protective effects against albuminuria and DN.

Portuguese-Brazilian evidence-based guideline on the management of hyperglycemia in type 2 diabetes mellitus

BACKGROUND

In current management of type 2 diabetes (T2DM), cardiovascular and renal prevention have become important targets to be achieved. In this context, a joint panel of four endocrinology societies from Brazil and Portugal was established to develop an evidence-based guideline for treatment of hyperglycemia in T2DM.

METHODS

MEDLINE (via PubMed) was searched for randomized clinical trials, meta-analyses, and observational studies related to diabetes treatment. When there was insufficient high-quality evidence, expert opinion was sought. Updated positions on treatment of T2DM patients with heart failure (HF), atherosclerotic CV disease (ASCVD), chronic kidney disease (CKD), and patients with no vascular complications were developed. The degree of recommendation and the level of evidence were determined using predefined criteria.

RESULTS AND CONCLUSIONS

In non-pregnant adults, the recommended HbA1c target is below 7%. Higher levels are recommended in frail older adults and patients at higher risk of hypoglycemia. Lifestyle modification is recommended at all phases of treatment. Metformin is the first choice when HbA1c is 6.5-7.5%. When HbA1c is 7.5-9.0%, dual therapy with metformin plus an SGLT2i and/or GLP-1RA (first-line antidiabetic agents, AD1) is recommended due to cardiovascular and renal benefits. If an AD1 is unaffordable, other antidiabetic drugs (AD) may be used. Triple or quadruple therapy should be considered when HbA1c remains above target. In patients with clinical or subclinical atherosclerosis, the combination of one AD1 plus metformin is the recommended first-line therapy to reduce cardiovascular events and improve blood glucose control. In stable heart failure with low ejection fraction (< 40%) and glomerular filtration rate (eGFR) > 30 mL/min/1.73 m2, metformin plus an SGLT-2i is recommended to reduce cardiovascular mortality and heart failure hospitalizations and improve blood glucose control. In patients with diabetes-associated chronic kidney disease (CKD) (eGFR 30-60 mL/min/1.73 m2 or eGFR 30-90 mL/min/1.73 m2 with albuminuria > 30 mg/g), the combination of metformin and an SGLT2i is recommended to attenuate loss of renal function, reduce albuminuria and improve blood glucose control. In patients with severe renal failure, insulin-based therapy is recommended to improve blood glucose control. Alternatively, GLP-1RA, DPP4i, gliclazide MR and pioglitazone may be considered to reduce albuminuria. In conclusion, the current evidence supports individualizing anti-hyperglycemic treatment for T2DM.

Risk of Kidney Dysfunction IN Nafld

Background:

The timely identification of traditional and non-traditional precursors and risk factors for chronic kidney disease (CKD) (a common systemic disease defined as a decreased kidney function documented by reduced glomerular filtration rate, or markers of kidney damage, or both) is relevant in clinical practice, as CKD increases the risk of end-stage renal disease and other serious comorbidities. A possible relationship between non-alcoholic fatty liver disease (NAFLD) (which is to date the most common chronic disease worldwide) and CKD has recently gained significant attention of researchers.

Methods :

A systematic literature search using appropriate keywords was made in order to identify relevant articles that have investigated the association between NAFLD and CKD.

Results:

Several observational studies and meta-analyses have reported the existence of an independent association between NAFLD and risk of CKD in patients with and without diabetes. However, whilst the association between NAFLD and risk of prevalent CKD is strong across various patient populations, whether NAFLD is independently associated with the development and progression of CKD is still debatable. Moreover, emerging evidence now suggests a potential association between patatin-like phospholipase domain-containing protein-3 (PNPLA3) rs738409 genotype (the most important genetic variant associated to NAFLD) and decreasing kidney function, independent of NAFLD.

Conclusions :

Convincing evidence now indicates that CKD is increased among patients with NAFLD. For this reason, patients with NAFLD should be regularly monitored for renal function and, on the other hand , NAFLD should be considered in all patients with CKD, especially if they are obese or have type 2 diabetes.

Lipotoxicity, Nutrient-Sensing Signals, and Autophagy in Diabetic Nephropathy

Diabetic nephropathy is a leading cause of proteinuria, kidney fibrosis, and subsequent end-stage renal disease. The renal prognosis of diabetic patients with refractory proteinuria is extremely poor. Therefore, identification of novel therapeutic targets to combat this serious condition and improve renal prognosis is urgently necessary. In diabetic patients, in addition to blood glucose levels, serum levels of free fatty acids (FFAs) are chronically elevated, even during postprandial periods. Of the various types of FFAs, saturated FFAs are highly cytotoxic and their levels are elevated in the serum of patients with diabetes. Thus, an increase in saturated FFAs is currently thought to contribute to proximal tubular cell damage and podocyte injury in diabetic nephropathy. Therefore, protecting both types of kidney cells from saturated FFA-related lipotoxicity may become a novel therapeutic approach for diabetic patients with refractory proteinuria. Interestingly, accumulating evidence suggests that controlling intracellular nutrient signals and autophagy can ameliorate the FFA-related kidney damage. Here, we review the evidence indicating possible mechanisms underlying cell injury caused by saturated FFAs and cell protective roles of intracellular nutrient signals and autophagy in diabetic nephropathy.

PPARγ and Its Agonists in Chronic Kidney Disease

Chronic kidney disease (CKD) has become a global healthcare issue. CKD can progress to irreversible end-stage renal diseases (ESRD) or renal failure. The major risk factors for CKD include obesity, diabetes, and cardiovascular diseases. Understanding the key process involved in the disease development may lead to novel interventive strategies, which is currently lagging behind. Peroxisome proliferator-activated receptor γ (PPARγ) is one of the ligand-activated transcription factor superfamily members and is globally expressed in human tissues. Its agonists such as thiazolidinediones (TZDs) have been applied as effective antidiabetic drugs as they control insulin sensitivity in multiple metabolic tissues. Besides, TZDs exert protective effects in multiple other CKD risk disease contexts. As PPARγ is abundantly expressed in major kidney cells, its physiological roles in those cells have been studied in both cell and animal models. The function of PPARγ in the kidney ranges from energy metabolism, cell proliferation to inflammatory suppression, although major renal side effects of existing agonists (including TZDs) have been reported, which limited their application in treating CKD. In the current review, we systemically assess the function of PPARγ in CKDs and the benefits and current limitations of its agonists in the clinical applications.

Effect of hyperglycemia and rosiglitazone on renal and urinary neprilysin in db/db diabetic mice

Alteration in renin-angiotensin system (RAS) has been implicated in the pathophysiology of diabetic kidney disease (DKD). The deleterious actions of angiotensin II (Ang II) could be antagonized by the formation of Ang-(1-7), generated by the actions of angiotensin-converting enzyme 2 (ACE2) and neprilysin (NEP). NEP degrades several peptides, including natriuretic peptides, bradykinin, amyloid beta, and Ang I. Although combination of Ang II receptor and NEP inhibitor treatment benefits patients with heart failure, the role of NEP in renal pathophysiology is a matter of active research. NEP pathway is a potent enzyme in Ang I to Ang-(1-7) conversion in the kidney of ACE2-deficient mice, suggesting a renoprotective role of NEP. The aim of the study is to test the hypothesis that chronic hyperglycemia downregulates renal NEP protein expression and activity in db/db diabetic mice and treatment with rosiglitazone normalizes hyperglycemia, renal NEP expression, and attenuates albuminuria. Mice received rosiglitazone (20 mg kg-1  day-1 ) for 10 weeks. Western blot analysis, immunohistochemistry, and enzyme activity revealed a significant decrease in renal and urinary NEP expression and activity in 16-wk db/db mice compared with lean control (p < .0001). Rosiglitazone also attenuated albuminuria and increased renal and urinary NEP expressions (p < .0001). In conclusion, data support the hypothesis that diabetes decreases intrarenal NEP, which could have a pivotal role in the pathogenesis of DKD. Urinary NEP may be used as an index of intrarenal NEP status. The renoprotective effects of rosiglitazone could be mediated by upregulation of renal NEP expression and activity in db/db diabetic mice.

Safety and efficacy of antihyperglycaemic agents in diabetic kidney disease

Diabetic kidney disease (DKD) is the major contributor to the mortality and the financial burden of diabetes, accounting for approximately 50% of the cases of end-stage renal disease (ESRD) in the developed world. Several studies have already demonstrated that achieving blood pressure targets in DKD with agents blocking the renin-angiotensin system confer superior renoprotection when compared to other agents. However, the effects on renal outcomes of antihyperglycaemic agents in these patients have not been reported or studied broadly until recent years. The intent of this article is to review the available data on safety, efficacy, impact on renal outcomes and pathophysiology implications of the most utilized antihyperglycaemic agents in DKD/ESRD.

MicroRNA-29a Attenuates Diabetic Glomerular Injury through Modulating Cannabinoid Receptor 1 Signaling

Diabetic nephropathy often leads to end-stage renal disease and life-threatening morbidities. Simple control of risk factors is insufficient to prevent the progression of diabetic nephropathy, hence the need for discovering new treatments is of paramount importance. Recently, the dysregulation of microRNAs or the cannabinoid signaling pathway has been implicated in the pathogenesis of various renal tubulointerstitial fibrotic damages and thus novel therapeutic targets for chronic kidney diseases have emerged; however, the role of microRNAs or cannabinoid receptors on diabetes-induced glomerular injuries remains to be elucidated. In high-glucose-stressed renal mesangial cells, transfection of a miR-29a precursor sufficiently suppressed the mRNA and protein expressions of cannabinoid type 1 receptor (CB1R). Our data also revealed upregulated CB1R, interleukin-1β, interleukin-6, tumor necrosis factor-α, c-Jun, and type 4 collagen in the glomeruli of streptozotocin (STZ)-induced diabetic mice, whereas the expression of peroxisome proliferator-activated receptor-γ (PPAR-γ) was decreased. Importantly, using gain-of-function transgenic mice, we demonstrated that miR-29a acts as a negative regulator of CB1R, blocks the expressions of these proinflammatory and profibrogenic mediators, and attenuates renal hypertrophy. We also showed that overexpression of miR-29a restored PPAR-γ signaling in the renal glomeruli of diabetic animals. Collectively, our findings indicate that the interaction between miR-29a, CB1R, and PPAR-γ may play an important role in protecting diabetic renal glomeruli from fibrotic injuries.

Narrative review of the effects of antidiabetic drugs on albuminuria

Diabetes mellitus is the most prevalent metabolic disorder worldwide. Glycemic control is the main focus of antidiabetic therapy. However, there are data suggesting that some antidiabetic drugs may have intrinsic beneficial renal effects and protect against the development and progression of albuminuria, thus minimizing the risk of diabetic nephropathy. These pharmacological agents can suppress upstream molecular pathways involved in the pathophysiology of diabetes-induced renal dysfunction such as oxidative stress, inflammatory responses, and apoptosis. In this narrative review, the pathophysiology of albuminuria in patients with diabetic nephropathy is discussed. Furthermore, the renoprotective effects of antidiabetic drugs, focusing on albuminuria, are reviewed.

Effects of glucose-lowering agents on surrogate endpoints and hard clinical renal outcomes in patients with type 2 diabetes

Diabetic kidney disease (DKD) represents an enormous burden in patients with type 2 diabetes mellitus (T2DM). Preclinical studies using most glucose-lowering agents have suggested renal-protective effects, but the proposed mechanisms of renoprotection have yet to be defined, and the promising results from experimental studies remain to be translated into human clinical findings to improve the prognosis of patients at risk of DKD. Also, it is important to distinguish effects on surrogate endpoints, such as decreases in albuminuria and estimated glomerular filtration rate (eGFR), and hard clinical endpoints, such as progression to end-stage renal disease (ESRD) and death from renal causes. Data regarding insulin therapy are surprisingly scarce, and it is nearly impossible to separate the effects of better glucose control from those of insulin per se, whereas favourable preclinical data with metformin, thiazolidinediones and dipeptidyl peptidase (DPP)-4 inhibitors are plentiful, and positive effects have been observed in clinical studies, at least for surrogate endpoints. The most favourable renal results have been reported with glucagon-like peptide-1 receptor agonists (GLP-1RAs) and sodium-glucose cotransporter type-2 inhibitors (SGLT2is). Significant reductions in both albuminuria and eGFR decline have been reported with these classes of glucose-lowering medications compared with placebo and other glucose-lowering agents. Moreover, in large prospective cardiovascular outcome trials using composite renal outcomes as secondary endpoints, both GLP-1RAs and SGLT2is added to standard care reduced renal outcomes combining persistent macro-albuminuria, doubling of serum creatinine, progression to ESRD and kidney-related death; however, to date, only SGLT2is have been clearly shown to reduce such hard clinical outcomes. Yet, as the renoprotective effects of SGLT2is and GLP-1RAs appear to be independent of glucose-lowering activity, the underlying mechanisms are still a matter of debate. For this reason, further studies with renal outcomes as primary endpoints are now awaited in T2DM patients at high risk of DKD, including trials evaluating the potential add-on benefits of combined GLP-1RA-SGLT2i therapies.