Nephroprotection by Hypoglycemic Agents: Do We Have Supporting Data?

Empagliflozin's role in early tubular protection for type 2 diabetes patients

BACKGROUND

Patients with type 2 diabetes often face early tubular injury, necessitating effective treatment strategies. This study aimed to evaluate the impact of the SGLT2 inhibitor empagliflozin on early tubular injury biomarkers in type 2 diabetes patients with normoalbuminuria.

METHODS

A randomized controlled clinical study comprising 54 patients selected based on specific criteria was conducted. Patients were divided into an intervention group (empagliflozin, n = 27) and a control group (n = 27) and treated for 6 weeks. Tubular injury biomarkers KIM-1 and NGAL were assessed pre- and post-treatment.

RESULTS

Both groups demonstrated comparable baseline characteristics. Post-treatment, fasting and postprandial blood glucose levels decreased similarly in both groups. The intervention group exhibited better improvements in total cholesterol, low-density lipoprotein, and blood uric acid levels. Renal function indicators, including UACR and eGFR, showed greater enhancements in the intervention group. Significant reductions in KIM-1 and NGAL were observed in the intervention group.

CONCLUSION

Treatment with empagliflozin in type 2 diabetes patients with normoalbuminuria led to a notable decrease in tubular injury biomarkers KIM-1 and NGAL. These findings highlight the potential of SGLT2 inhibitors in early tubular protection, offering a new therapeutic approach.

Assessing early tubular protective effects of SGLT2 inhibitor empagliflozin against type 2 diabetes mellitus using functional magnetic resonance imaging

AIMS

To observe the alterations in functional magnetic resonance imaging parameters in normoalbuminuric type 2 diabetic patients undergoing SGLT2 inhibitor empagliflozin treatment and investigate the early tubular protective effects of the inhibitor.

METHODS

This study was performed in normoalbuminuric type 2 diabetes mellitus patients (UACR < 30 mg/g, eGFR ≥ 60 ml/min/1.73 m2). The patients were divided into the intervention group (empagliflozin) and the control group (27 cases each). The intervention group was treated with 10 mg/day empagliflozin tablets orally, while the control group had adjustments to their basic treatment stage. The patients were treated for 6 weeks.

RESULTS

The baseline clinical data of the two groups were comparable (P˃0.05). The intervention group exhibited better improvements in blood lipid profiles and more significant reductions in blood uric acid levels compared to the control group (P < 0.05). The two groups had No significant difference in blood pressure changes (P˃0.05). Notably, the intervention group demonstrated a greater reduction in UACR and a more substantial decline in eGFR than the control group (P < 0.05). Regarding functional magnetic resonance imaging parameters, the MD value of the renal medulla region in the intervention group increased after treatment, while the MR2* value of the renal medulla region decreased (P < 0.05).

CONCLUSIONS

SGLT2 inhibitor empagliflozin can reduce UACR and eGFR levels in early type 2 diabetic patients with normal proteinuria. Moreover, empagliflozin therapy led to an increase in the MD value and a decrease in the MR2* value of the renal medulla, evidencing the early tubular protective effects of this therapy.

Renoprotective Potency of Sitagliptin versus Pioglitazone in Type 2 Diabetic Patients: Impact on LncMIAT

Background: Diabetes mellitus (DM) represents one of the most important reasons for chronic kidney diseases due to the high level of blood glucose that destructs blood vessels. Objective: The present study focused on investigating the protective impact of sitagliptin on kidney complication in type 2 diabetes mellitus (T2DM) patients in comparison to pioglitazone to examine which has the superior effect against the nephritic complication of DM. Methods: Eighty adult subjects were classified into four groups: control group, pioglitazone-treated T2DM patients (P group), sitagliptin-treated T2DM patients for less than one year (SL group), and sitagliptin-treated T2DM patients for more than one year (SM group). Blood samples were withdrawn from all subjects for analysis of neutrophil gelatinase-associated lipocalin (NGAL), vanin-1, kidney injury molecule-1 (KIM-1), glyoxalase-1 (Glo-1), methylglyoxal (MG), cystatin-C, and interleukin-18 (IL-18) using competitive ELISA kits. Also, long noncoding myocardial infarction associated transcript (lncMIAT) was measured in whole blood using qRT-PCR. Results: The present study revealed that the lncMIAT expression level was significantly higher in the P group as compared to the SL group, SM group, or healthy control group. Additionally, serum NGAL, vanin-1, KIM-1, Glo-1, MG, and cystatin-C were significantly higher in the P group and SL group as compared to the SM group and healthy control group. Conclusion: Sitagliptin protected the kidney through downregulation of lncMIAT besides amelioration of kidney injury marker levels, which was more preferable than in pioglitazone therapy.

Nephroprotective plant species used in traditional Mayan Medicine for renal-associated diseases

ETHNOPHARMACOLOGICAL RELEVANCE

The prevalence of kidney disease has increased rapidly in recent years and has emerged as one of the leading causes of mortality worldwide. Natural products have been suggested as valuable nephroprotective agents due to their multi-target and synergistic effects on modulating important proteins involved in kidney injury. There is a large number of plant species that have been used traditionally for kidney-related conditions in Mesoamerican medicine by different cultural groups that could provide a valuable source of nephroprotective therapeutic candidates and could lead to potential drug discovery.

AIM OF REVIEW

This review aims to provide an overview of the currently known efficacy of plant species used traditionally in Mesoamerica by Mayan groups to treat kidney-related conditions and to analyze the phytochemical, pharmacological, molecular, toxicological, and clinical evidence to contribute to public health efforts and for directing future research.

METHODS

Primary sources of plant use reports for traditional kidney-related disorders in Mesoamerica were searched systematically from library catalogs, theses, and scientific databases (PubMed, Google Scholar; and Science Direct), and were filtered according to usage frequency in Mayan groups and plant endemism. The database of traditional plants was further analyzed based on associations with published reports of the phytochemical, pharmacological, molecular, toxicological, and clinical evidence.

RESULTS

The most reported kidney-related conditions used traditionally in Mayan medicine involve reducing renal damage (a cultural interpretation that considers an inflammatory or infectious condition), cleaning or purifying the blood and kidney, reducing kidney pain, and eliminating kidney stones. A total of 208 plants used for kidney-related problems by 10 Mayan groups were found, representing 143 native species, where only 42 have reported pharmacological activity against kidney damage, mainly approached by in vitro and in vivo models of chemical- or drug-induced nephrotoxicity, diabetes nephropathy, and renal injury produced by hypertension. Nephroprotective effects are mainly mediated by reducing oxidative stress, inflammatory response, fibrosis mechanisms, and apoptosis in the kidney. The most common nephroprotective compounds associated with traditional Mayan medicine were flavonoids, terpenoids, and phenolic acids. The most widely studied traditional plants in terms of pharmacological evidence, bioactive compounds, and mechanisms of action, are Annona muricata L., Carica papaya L., Ipomoea batatas (L.) Lam., Lantana camara L., Sechium edule (Jacq.) Sw., Tagetes erecta L., and Zea mays L. Most of the plant species with reported pharmacological activity against kidney damage were considered safe in toxicological studies.

CONCLUSION

Available pharmacological reports suggest that several herbs used in traditional Mayan medicine for renal-associated diseases may have nephroprotective effects and consistent pharmacological evidence, nephroprotective compounds, and mechanisms of action in different models of kidney injury. However, more research is required to fully understand the potential of traditional Mayan medicine in drug discovery given the limited ethnobotanical studies and data available for most species with regards to identification on bioactive components, pharmacological mechanisms, and the scarce number of clinical studies.

Pleiotropic Effects of Sodium-Glucose Cotransporter-2 Inhibitors: Renoprotective Mechanisms beyond Glycemic Control

Diabetes mellitus is a major cause of chronic kidney disease and end-stage renal disease. However, the management of chronic kidney disease, particularly diabetes, requires vast improvements. Recently, sodium-glucose cotransporter-2 (SGLT2) inhibitors, originally developed for the treatment of diabetes, have been shown to protect against kidney injury via glycemic control, as well as various other mechanisms, including blood pressure and hemodynamic regulation, protection from lipotoxicity, and uric acid control. As such, regulation of these mechanisms is recommended as an effective multidisciplinary approach for the treatment of diabetic patients with kidney disease. Thus, SGLT2 inhibitors are expected to become key drugs for treating diabetic kidney disease. This review summarizes the recent clinical evidence pertaining to SGLT2 inhibitors as well as the mechanisms underlying their renoprotective effects. Hence, the information contained herein will advance the current understanding regarding the pleiotropic effects of SGLT2 inhibitors, while promoting future research in the field.

Geraniol ameliorates diabetic nephropathy via interference with miRNA-21/PTEN/Akt/mTORC1 pathway in rats

Deregulated activity of protein kinase B/mammalian target of rapamycin complex-1 (Akt/mTORC1) incites crucial pathological characteristics of diabetic nephropathy. The acyclic monoterpene geraniol has been recently reported to possess antidiabetic effects; however, its potential renoprotective effect in diabetes has not yet been elucidated. This study aimed to assess the possible modulatory effect of geraniol on the Akt/mTORC1 pathway in diabetes-induced nephropathy in rats compared to the standard antidiabetic drug gliclazide. Geraniol and gliclazide was administered daily to diabetic rats for 6 weeks starting on the 3rd-day post diabetes induction by streptozotocin (STZ). Geraniol amended the deteriorated renal function (serum creatinine; blood urea nitrogen). It exerted a remarkable antihyperglycemic effect that is comparable to that of gliclazide and suppressed the fibrotic marker, transforming growth factor-β. Geraniol restored redox balance and inhibited lipid peroxidation by reducing nicotine amide adenine dinucleotide phosphate oxidase and enhancing the antioxidant enzyme, superoxide dismutase. These beneficial effects were associated with a robust downregulation of miRNA-21 and consequently, reversion of tumor suppressor protein phosphatase and tension homolog (PTEN)/Akt/mTORC1 cue and its downstream proteins required for mesangial cell proliferation and matrix protein synthesis. The current study indicates that geraniol interfered with miRNA-21/ PTEN/AKT/mTORC1 pathway signaling that contributes largely to the progression of mesangial expansion and extracellular matrix deposition in diabetic nephropathy.

GLP-1 Receptor Agonists and Diabetic Kidney Disease: A Call of Attention to Nephrologists

Type 2 diabetes mellitus (T2DM) represents the main cause of chronic kidney disease (CKD) and end-stage renal disease (ESKD), and diabetic kidney disease (DKD) is a major cause of morbidity and mortality in diabetes. Despite advances in the nephroprotective treatment of T2DM, DKD remains the most common complication, driving the need for renal replacement therapies (RRT) worldwide, and its incidence is increasing. Until recently, prevention of DKD progression was based around strict blood pressure (BP) control, using renin-angiotensin system blockers that simultaneously reduce BP and proteinuria, adequate glycemic control and control of cardiovascular risk factors. Glucagon-like peptide-1 receptor agonists (GLP-1RA) are a new class of anti-hyperglycemic drugs shown to improve cardiovascular and renal events in DKD. In this regard, GLP-1RA offer the potential for adequate glycemic control in multiple stages of DKD without an increased risk of hypoglycemia, preventing the onset of macroalbuminuria and slowing the decline of glomerular filtration rate (GFR) in diabetic patients, also bringing additional benefit in weight reduction, cardiovascular and other kidney outcomes. Results from ongoing trials are pending to assess the impact of GLP-1RA treatments on primary kidney endpoints in DKD.

SGLT-2 inhibitors and GLP-1 receptor agonists for nephroprotection and cardioprotection in patients with diabetes mellitus and chronic kidney disease. A consensus statement by the EURECA-m and the DIABESITY working groups of the ERA-EDTA

Chronic kidney disease (CKD) in patients with diabetes mellitus (DM) is a major problem of public health. Currently, many of these patients experience progression of cardiovascular and renal disease, even when receiving optimal treatment. In previous years, several new drug classes for the treatment of type 2 DM have emerged, including inhibitors of renal sodium-glucose co-transporter-2 (SGLT-2) and glucagon-like peptide-1 (GLP-1) receptor agonists. Apart from reducing glycaemia, these classes were reported to have other beneficial effects for the cardiovascular and renal systems, such as weight loss and blood pressure reduction. Most importantly, in contrast to all previous studies with anti-diabetic agents, a series of recent randomized, placebo-controlled outcome trials showed that SGLT-2 inhibitors and GLP-1 receptor agonists are able to reduce cardiovascular events and all-cause mortality, as well as progression of renal disease, in patients with type 2 DM. This document presents in detail the available evidence on the cardioprotective and nephroprotective effects of SGLT-2 inhibitors and GLP-1 analogues, analyses the potential mechanisms involved in these actions and discusses their place in the treatment of patients with CKD and DM.

Odds of Acute Kidney Injury in Patients Receiving Dipeptidyl Peptidase 4 Inhibitors: A National Cohort Study Within the Department of Veterans Affairs

Preclinical and clinical data of dipeptidyl peptidase 4 (DPP-4) inhibitors have demonstrated discordant data regarding acute kidney injury (AKI). Therefore, we aimed to evaluate the association between DPP-4 use and AKI. This cohort study utilized data from the Department of Veterans Affairs evaluating patients diagnosed with type 2 (T2) diabetes with a DPP-4 inhibitor and compared with nondiabetic and diabetic patients. The primary end point is the development of AKI, and statistical analyses were performed to examine the association. DPP-4 use is associated with a lower odds of AKI compared with diabetics (adjusted odds ratio (OR) = 0.39; 95% confidence interval (CI) = 0.32-0.48) and nondiabetics (OR = 0.64; 95% CI = 0.52-0.79). DPP-4 use in patients with T2 diabetes mellitus is associated with lower odds of AKI within 120 days compared with nondiabetic and diabetic controls when adjusting for study covariates.

Canagliflozin and Renal Events in Diabetes with Established Nephropathy Clinical Evaluation and Study of Diabetic Nephropathy with Atrasentan: what was learned about the treatment of diabetic kidney disease with canagliflozin and atrasentan?

In April 2019, two major Phase 3 randomized clinical trials were published that assessed primary renal outcomes in diabetic kidney disease (DKD) in type 2 diabetes mellitus (T2DM). The Canagliflozin and Renal Events in Diabetes with Established Nephropathy Clinical Evaluation (CREDENCE) tested an already available antidiabetic drug, canagliflozin, and the Study of Diabetic Nephropathy with Atrasentan (SONAR) tested a novel molecule, the endothelin-1 receptor blocker atrasentan, both on top of renin-angiotensin system blockade. Both trials demonstrated significant nephroprotection in patients with overt DKD (albuminuria >300 mg/g urinary creatinine) for combined primary endpoints of end-stage kidney disease (ESKD), doubling of serum creatinine or death from renal or cardiovascular causes in CREDENCE {hazard ratio [HR] 0.70 [95% confidence interval (CI) 0.59-0.82]} and ESKD and doubling of serum creatinine in SONAR [HR 0.65 (95% CI 0.49-0.88)]. Canagliflozin also decreased the secondary renal endpoint ESKD, doubling of serum creatinine or renal death [HR 0.66 (95% CI 0.53-0.81)], which was similar in nature and impact to the primary endpoint in SONAR. In addition, canagliflozin decreased a secondary endpoint of cardiovascular death or hospitalization for heart failure [HR 0.69 (95% CI 0.57-0.83)], whereas atrasentan had no significant impact on a secondary cardiovascular composite endpoint or on hospital admissions for heart failure and, despite restrictive exclusion criteria, there was a non-significant trend towards more frequent episodes of heart failure. Based on these results, canagliflozin will likely be approved for the indication of treating DKD in T2DM and the estimated glomerular filtration rate threshold for prescribing it will be lifted, whereas the future and place of atrasentan in the treatment of DKD remain unclear.

Role of the sodium-hydrogen exchanger in mediating the renal effects of drugs commonly used in the treatment of type 2 diabetes

Diabetes is characterized by increased activity of the sodium-hydrogen exchanger (NHE) in the glomerulus and renal tubules, which contributes importantly to the development of nephropathy. Despite the established role played by the exchanger in experimental studies, it has not been specifically targeted by those seeking to develop novel pharmacological treatments for diabetes. This review demonstrates that many existing drugs that are commonly prescribed to patients with diabetes act on the NHE1 and NHE3 isoforms in the kidney. This action may explain their effects on sodium excretion, albuminuria and the progressive decline of glomerular function in clinical trials; these responses cannot be readily explained by the influence of these drugs on blood glucose. Agents that may affect the kidney in diabetes by virtue of an action on NHE include: (1) insulin and insulin sensitizers; (2) incretin-based agents; (3) sodium-glucose cotransporter 2 inhibitors; (4) antagonists of the renin-angiotensin system (angiotensin converting-enzyme inhibitors, angiotensin receptor blockers and angiotensin receptor neprilysin inhibitors); and (5) inhibitors of aldosterone action and cholesterol synthesis (spironolactone, amiloride and statins). The renal effects of each of these drug classes in patients with type 2 diabetes may be related to a single shared biological mechanism.

Renoprotective Effects of the Dipeptidyl Peptidase-4 Inhibitor Sitagliptin: A Review in Type 2 Diabetes

Diabetic nephropathy (DN) is now the single commonest cause of end-stage renal disease (ESRD) worldwide and one of the main causes of death in diabetic patients. It is also acknowledged as an independent risk factor for cardiovascular disease (CVD). Since sitagliptin was approved, many studies have been carried out revealing its ability to not only improve metabolic control but also ameliorate dysfunction in various diabetes-targeted organs, especially the kidney, due to putative underlying cytoprotective properties, namely, its antiapoptotic, antioxidant, anti-inflammatory, and antifibrotic properties. Despite overall recommendations, many patients spend a long time well outside the recommended glycaemic range and, therefore, have an increased risk for developing micro- and macrovascular complications. Currently, it is becoming clearer that type 2 diabetes mellitus (T2DM) management must envision not only the improvement in glycaemic control but also, and particularly, the prevention of pancreatic deterioration and the evolution of complications, such as DN. This review aims to provide an overview of the current knowledge in the field of renoprotective actions of sitagliptin, namely, improvement in diabetic dysmetabolism, hemodynamic factors, renal function, diabetic kidney lesions, and cytoprotective properties.

Effects of canagliflozin on cardiovascular risk factors in patients with type 2 diabetes mellitus

BACKGROUND AND AIMS

Cardiovascular disease is the most common cause of morbidity and mortality among people with type 2 diabetes mellitus (T2DM). The main contributors to cardiovascular risk in T2DM are chronic hyperglycaemia, reduced insulin sensitivity, hypertension and dyslipidaemia. Other cardiovascular risk factors include obesity and visceral adiposity, increased arterial stiffness and renal dysfunction. Results from clinical trials, including a long-term cardiovascular outcome study, have shown that sodium glucose co-transporter 2 (SGLT2) inhibitors can provide multiple cardiometabolic benefits beyond glycaemic control including inducing mild osmotic diuresis, natriuresis and weight loss. This review article describes the effects of canagliflozin on cardiovascular risk factors based on results from its clinical development programme.

METHODS

This review is based on structured searches to identify literature related to the effects of canagliflozin on cardiovascular risk factors in patients with T2DM.

DISCUSSION AND CONCLUSIONS

Canagliflozin treatment has been shown to provide glycaemic improvements as well as reductions in blood pressure and body weight across a broad range of patients with T2DM, including those with elevated cardiovascular risk. Other observed effects of canagliflozin that may contribute to improved cardiometabolic outcomes include reduction in uric acid levels, decreased albuminuria and increases in serum magnesium. Results of ongoing long-term cardiovascular outcomes studies of canagliflozin are expected to provide additional evidence on the cardiometabolic effects of canagliflozin treatment.

Place of sodium-glucose cotransporter-2 inhibitors in East Asian subjects with type 2 diabetes mellitus: Insights into the management of Asian phenotype

The burden of type 2 diabetes (T2DM) in East Asia is alarming. Rapid modernization and urbanization have led to major lifestyle changes and a tremendous increase in the prevalence of obesity, metabolic syndrome, and diabetes mellitus. The development of T2DM at a younger age, with lower body mass index, higher visceral adiposity, and more significant pancreatic beta-cell dysfunction compared to Caucasians are factors responsible for the increased prevalence of T2DM in East Asians. Sodium-glucose Cotransporter-2 (SGLT2) inhibitors (canagliflozin, dapaglifozin, empagliflozin, etc.) reduce renal glucose reabsorption, leading to favorable effects on glycemic, blood pressure, and weight control. The insulin-independent mechanism enables their use as monotherapy or combination therapy with insulin and other oral antidiabetic agents. The role of SGLT2 inhibitors in the management of T2DM among East Asians is an interesting area of research, given that East Asians have been proven to be uniquely different from Caucasians. This review provides comprehensive coverage of the available literature not only on the efficacy and safety, but also on the recent cardiovascular and renal outcomes of SGLT2 inhibitors, focusing among East Asians.

Effects of reducing blood pressure on renal outcomes in patients with type 2 diabetes: Focus on SGLT2 inhibitors and EMPA-REG OUTCOME

Empagliflozin, a sodium-glucose cotransporter type 2 (SGLT2) inhibitor, has enabled remarkable reductions in cardiovascular and all-cause mortality as well as in renal outcomes in patients with type 2 diabetes (T2D) and a history of cardiovascular disease in the EMPA-REG OUTCOME. These results have been attributed to haemodynamic rather than metabolic effects, in part due to the osmotic/diuretic action of empagliflozin and the reduction in arterial blood pressure (BP). The present narrative review includes the results of meta-analyses of trials evaluating the effects on renal outcomes of lowering BP in patients with T2D, with a special focus on the influence of baseline and achieved systolic BP, and compares the renal outcome results of the EMPA-REG OUTCOME with those of other major trials with inhibitors of the renin-angiotensin system in patients with T2D and the preliminary findings with other SGLT2 inhibitors, and also evaluates post hoc analyses from the EMPA-REG OUTCOME of special interest as regards the BP-lowering hypothesis and renal function. While systemic BP reduction associated to empagliflozin therapy may have contributed to the renal benefits reported in EMPA-REG OUTCOME, other local mechanisms related to kidney homoeostasis most probably also played a role in the overall protection observed in the trial.

Association of Increasing GFR with Change in Albuminuria in the General Population

BACKGROUND AND OBJECTIVES

Hyperfiltration at the single-nephron level has been proposed as an early stage of kidney dysfunction of different origins. Evidence supporting this hypothesis in humans is lacking, because there is no method of measuring single-nephron GFR in humans. However, increased whole-kidney GFR in the same individual implies an increased single-nephron GFR, because the number of nephrons does not increase with age. We hypothesized that an increase in GFR would be associated with an increased albumin-to-creatinine ratio in a cohort of the general population.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We measured GFR by iohexol clearance at baseline in 2007-2009 and follow-up after 5.6 years in a representative sample of 1246 persons (aged 50-62 years) who were nondiabetic from the general population of Tromso, northern Norway. Participants were without cardiovascular disease, kidney disease, or diabetes at baseline. We investigated the association between change in GFR and change in albumin-to-creatinine ratio. Increased GFR was defined as a positive change in GFR (change in GFR>0 ml/min) from baseline to follow-up. An albumin-to-creatinine ratio >30 mg/g was classified as albuminuria.

RESULTS

Change in GFR was positively associated with a change in albumin-to-creatinine ratio in the entire cohort in the multiple linear regression. The albumin-to-creatinine ratiofollow-up-to-albumin-to-creatinine ratiobaseline ratio increased by 8.0% (95% confidence interval, 1.4 to 15.0) per SD increase in change in GFR. When participants with increased GFR (n=343) were compared with those with a reduced GFR (n=903), the ratio increased by 16.3% (95% confidence interval, 1.1 to 33.7). The multivariable adjusted odds ratio for incident albuminuria (n=14) was 4.98 (95% confidence interval, 1.49 to 16.13) for those with an increased GFR (yes/no).

CONCLUSIONS

Increasing GFR is associated with an increase in albumin-to-creatinine ratio and incident albuminuria in the general nondiabetic population. These findings support single-nephron hyperfiltration as a risk factor for albuminuria in the general population.

[Diabetes mellitus and chronic kidney disease: Possibilities of prediction, early diagnosis, and nephroprotection in the 21st century]

The. review gives data on the prognostic value of genetic markers when analyzing the risk of chronic kidney disease in diabetes mellitus, those on new possibilities of early diagnosis of diabetic nephropathy using urinary biomarkers (nephrinuria, podocinuria) and proteomic urinalysis at the stage of normoalbuminuria. The interpretation of the index mrcroalbuminuria in type 2 diabetesis critically analyzed. The nephroprotective properties of novel classes of glucose-lowering drugs, such as incretins and gliflozins, are considered.