Nephroprotection by SGLT2 Inhibition: Back to the Future?

Favorable changes in the eGFR slope after dapagliflozin treatment and its association with the initial dip

BACKGROUND

Renoprotective effects of sodium glucose transporter 2 (SGLT2) inhibitors, including dapagliflozin, were observed in randomized controlled trials (RCTs). The suspected underlying mechanism is a correction of hyperfiltration, observed as an "initial dip". Whether SGLT2 inhibitors can attenuate the rate of decline in the estimated glomerular filtration rate (eGFR) in clinical settings, even when considering the pre-treatment decline rate, is unknown. Although several RCTs identified an association between the initial dip and long-term renal prognoses, a conclusion has not been reached.

METHODS

We collected the eGFR data of patients for whom dapagliflozin was initiated in our hospital and then calculated their eGFR slopes before and after the start of the treatment. We investigated the changes in the eGFR slopes (ΔeGFR slope) and the association between the ΔeGFR slope and the initial dip. Risks for rapid eGFR decliners (eGFR slope < - 3 mL/min/1.73 m2/year) were also examined.

RESULTS

The eGFR slope was significantly milder after dapagliflozin treatment (p < 0.01). A deeper initial dip was associated with a milder rate of eGFR decline (adjusted beta: - 0.29, p < 0.001). Dapagliflozin treatment reduced the proportion of rapid eGFR decliners from 52.9 to 14.7%, and a smaller initial dip was identified as a significant risk for post-treatment rapid eGFR decline (adjusted odds ratio: 1.73, p < 0.05).

CONCLUSIONS

Compared to before the administration of dapagliflozin, the rate of eGFR decline was significantly milder after its administration. The initial dip was significantly associated with long-term renoprotective effects and may be a useful predictor of treatment response.

Refractory IgA Nephropathy: A Challenge for Future Nephrologists

IgA nephropathy (IgAN) represents the most prevalent form of primary glomerulonephritis, and, on a global scale, it ranks among the leading culprits behind end-stage kidney disease (ESKD). Presently, the primary strategy for managing IgAN revolves around optimizing blood pressure and mitigating proteinuria. This is achieved through the utilization of renin-angiotensin system (RAS) inhibitors, namely, angiotensin-converting enzyme inhibitors (ACEi) and angiotensin receptor blockers (ARBs). As outlined by the KDIGO guidelines, individuals who continue to show a persistent high risk of progressive ESKD, even with comprehensive supportive care, are candidates for glucocorticoid therapy. Despite these therapies, some patients have a disease refractory to treatment, defined as individuals that present a 24 h urinary protein persistently >1 g after at least two rounds of regular steroids (methylprednisolone or prednisone) and/or immunosuppressant therapy (e.g., mycophenolate mofetil), or who do not tolerate regular steroids and/or immunosuppressant therapy. The aim of this Systematic Review is to revise the current literature, using the biomedical database PubMed, to investigate possible therapeutic strategies, including SGLT2 inhibitors, endothelin receptor blockers, targeted-release budesonide, B cell proliferation and differentiation inhibitors, fecal microbiota transplantation, as well as blockade of complement components.

Kidney Fibrosis and Oxidative Stress: From Molecular Pathways to New Pharmacological Opportunities

Kidney fibrosis, diffused into the interstitium, vessels, and glomerulus, is the main pathologic feature associated with loss of renal function and chronic kidney disease (CKD). Fibrosis may be triggered in kidney diseases by different genetic and molecular insults. However, several studies have shown that fibrosis can be linked to oxidative stress and mitochondrial dysfunction in CKD. In this review, we will focus on three pathways that link oxidative stress and kidney fibrosis, namely: (i) hyperglycemia and mitochondrial energy imbalance, (ii) the mineralocorticoid signaling pathway, and (iii) the hypoxia-inducible factor (HIF) pathway. We selected these pathways because they are targeted by available medications capable of reducing kidney fibrosis, such as sodium-glucose cotransporter-2 (SGLT2) inhibitors, non-steroidal mineralocorticoid receptor antagonists (MRAs), and HIF-1alpha-prolyl hydroxylase inhibitors. These drugs have shown a reduction in oxidative stress in the kidney and a reduced collagen deposition across different CKD subtypes. However, there is still a long and winding road to a clear understanding of the anti-fibrotic effects of these compounds in humans, due to the inherent practical and ethical difficulties in obtaining sequential kidney biopsies and the lack of specific fibrosis biomarkers measurable in easily accessible matrices like urine. In this narrative review, we will describe these three pathways, their interconnections, and their link to and activity in oxidative stress and kidney fibrosis.

Antifibrotic effects of sodium-glucose cotransporter-2 inhibitors: A comprehensive review

BACKGROUND AND AIMS

Scar tissue accumulation in organs is the underlying cause of many fibrotic diseases. Due to the extensive array of organs affected, the long-term nature of fibrotic processes and the large number of people who suffer from the negative impact of these diseases, they constitute a serious health problem for modern medicine and a huge economic burden on society. Sodium-glucose cotransporter-2 inhibitors (SGLT2is) are a relatively new class of anti-diabetic pharmaceuticals that offer additional benefits over and above their glucose-lowering properties; these medications modulate a variety of diseases, including fibrosis. Herein, we have collated and analyzed all available research on SGLT2is and their effects on organ fibrosis, together with providing a proposed explanation as to the underlying mechanisms.

METHODS

PubMed, ScienceDirect, Google Scholar and Scopus were searched spanning the period from 2012 until April 2023 to find relevant articles describing the antifibrotic effects of SGLT2is.

RESULTS

The majority of reports have shown that SGLT2is are protective against lung, liver, heart and kidney fibrosis as well as arterial stiffness. According to the results of clinical trials and animal studies, many SGLT2 inhibitors are promising candidates for the treatment of fibrosis. Recent studies have demonstrated that SGLT2is affect an array of cellular processes, including hypoxia, inflammation, oxidative stress, the renin-angiotensin system and metabolic activities, all of which have been linked to fibrosis.

CONCLUSION

Extensive evidence indicates that SGLT2is are promising treatments for fibrosis, demonstrating protective effects in various organs and influencing key cellular processes linked to fibrosis.

Assessment of Knowledge and Perception of Sodium-Glucose Co-transporter 2 (SGLT-2) Inhibitors Prescription among Physicians in Saudi Arabia

BACKGROUND

Sodium-glucose cotransporter 2 inhibitors are a new class of medications that have been proven to improve both glycemic control and cardio-renal outcomes. The knowledge, attitude, and perception toward their prescriptions in Jazan, Saudi Arabia, are still unknown.

OBJECTIVE

The study aimed to measure the level of knowledge and attitude toward sodium-glucose cotransporter 2 inhibitors prescription among physicians in the Jazan region, Saudi Arabia.

METHODS

Data analysis was performed using Statistical Package for the Social Sciences, SPSS 23rd version. Frequency and percentages were used to display categorical variables. Minimum, maximum, mean, and standard deviation were used to test numerical variables. Independent t-test and ANOVA test were both utilized to test the factors associated with knowledge and attitude toward the use of SGLT-2 inhibitors.

RESULTS

A total of 65 participants were included in the study. 26.2% had a low knowledge level, 30.8% had a moderate knowledge level, and 43.1% had a high knowledge level of sodium-glucose cotransporter 2 inhibitors. 9.2% had a low attitude level, 43.1% had a moderate attitude level, and 47.7% had a high attitude level toward sodium-glucose cotransporter 2 inhibitors. Age, professional status, years of experience, and specialty were significantly associated with attitude but not with the knowledge of sodium-glucose cotransporter 2 inhibitors prescription.

CONCLUSION

While the study cohort scored high in the knowledge and attitude domains of the survey, a large proportion failed to answer very essential questions in type 2 diabetes management. An educational awareness program needs to be carried out to strengthen the physicians' knowledge of SGLT2 inhibitors prescription.

The Interplay of Comorbidities in Chronic Heart Failure: Challenges and Solutions

BACKGROUND

Chronic heart failure (HF) is frequently associated with various comorbidities. These comorbid conditions, such as anemia, diabetes mellitus, renal insufficiency, and sleep apnea, can significantly impact the prognosis of patients with HF.

OBJECTIVE

This review aims to synthesize current evidence on the prevalence, impact, and management of comorbidities in patients with chronic HF.

METHODS

A comprehensive review was conducted, with a rigorous selection process. Out of an initial pool of 59,030 articles identified across various research modalities, 134 articles were chosen for inclusion. The selection spanned various research methods, from randomized controlled trials to observational studies.

RESULTS

Comorbidities are highly prevalent in patients with HF and contribute to increased hospitalization rates and mortality. Despite advances in therapies for HF with reduced ejection fraction, options for treating HF with preserved ejection fraction remain sparse. Existing treatment protocols often lack standardization, reflecting a limited understanding of the intricate relationships between HF and associated comorbidities.

CONCLUSION

There is a pressing need for a multidisciplinary, tailored approach to manage HF and its intricate comorbidities. This review underscores the importance of ongoing research efforts to devise targeted treatment strategies for HF patients with various comorbid conditions.

Albuminuria and Serum Tumor Necrosis Factor Receptor Levels in Patients with Type 2 Diabetes on SGLT2 Inhibitors: A Prospective Study

INTRODUCTION

Large-scale clinical trials of sodium-glucose cotransporter 2 inhibitors (SGLT2i) demonstrate proteinuria-reducing effects in diabetic kidney disease, even after treatment with renin-angiotensin inhibitors. The precise mechanism for this favorable effect remains unclear. This prospective open-label single-arm study investigated factors associated with a reduction in proteinuria after SGLT2i administration.

METHODS

Patients with type 2 diabetes (T2DM) who had glycated hemoglobin (HbA1c) levels ≥ 6.5% despite dietary and/or oral hypoglycemic monotherapy were recruited and administered the recommended daily dose of SGLT2i for 4 months. Dual primary outcomes were changes in the urine albumin-to-creatinine ratio (uACR) and urine liver-type fatty acid-binding protein (L-FABP)-to-creatinine ratio (uL-FABPCR) at month 4 from baseline. Changes in kidney injury, inflammation, and oxidative stress biomarkers were investigated as secondary endpoints to examine the effects of this treatment on the kidney. The correlation between renal outcomes and clinical indicators, including circulating tumor necrosis factor receptors (TNFR) 1 and 2, was evaluated using univariate and multivariate analyses.

RESULTS

Participants (n = 123) had a mean age of 64.1 years (SD 13.4), with 50.4% being male. The median BMI was 25.8 kg/m2 (interquartile range (IQR) 23.1-28.9), and the median HbA1c level was 7.3% (IQR 6.9-8.3). After SGLT2i administration, the uACR declined from 19.2 mg/gCr (IQR 7.1-48.7) to 13.3 mg/gCr (IQR 7.5-31.6), whereas the uL-FABPCR was not influenced. In univariate analysis, the change in log-transformed uACR due to SGLT2i administration showed a positive correlation with the change in serum TNFR1 level (R = 0.244, p < 0.01). Multivariate regression analysis, including confounding factors, showed that the changes in serum TNFR1 level were independently associated with the changes in the log-transformed uACR (independent t = 2.102, p < 0.05).

CONCLUSION

After the 4-month SGLT2i administration, decreased albuminuria level was associated with decreased serum TNFR level in patients with T2DM.

TRIAL REGISTRATION NUMBER

UMIN000031947.

Role of Estimated Glomerular Filtration Rate in Clinical Research: The Never-Ending Matter

Background

Chronic kidney disease (CKD) burden is crucial both on a global scale and at individual patient level, affecting morbidity and mortality directly and through its effect on both cardiovascular damage and CKD progression to end-stage-kidney-disease (ESKD). Unfortunately, the awareness of CKD is poor, with few CKD patients conscious of the severity of their health status. The principal biomarker of kidney function is estimated glomerular filtration rate (eGFR).

Methods

We searched the literature and present a review article with the aim of summarizing the role of eGFR in clinical research. In particular, we report the eGFR role as a prognostic, enrichment and endpoint biomarker and its role in the early detection of CKD.

Results

eGFR has a major role as a biomarker in clinical research. As a prognostic marker, eGFR reduction is associated with cardiovascular events, ESKD and mortality. As an enrichment biomarker, eGFR values are pivotal for selecting patients to be included in randomized and observational studies; it helps to test a pre-defined drug in early CKD or in more advanced CKD allowing also to avoid screening failures and to shorten the duration of clinical trials. Moreover, eGFR decline (expressed as a percentage of reduction from baseline or continuous slope) can be considered a good endpoint in clinic trials overcoming delays whilst waiting for hard endpoints to develop.

Conclusions

eGFR is a strong clinical measure for both observational and intervention studies. It is also helpful in screening the general population for kidney disease and, in particular, to increase awareness of CKD.

The efficacy and safety of SGLT2 inhibitors in patients with non-diabetic chronic kidney disease: a systematic review and meta-analysis

PURPOSE

In recent years, increasing evidence has shown that sodium-glucose cotransporter 2 inhibitors (SGLT2i) drugs have potential renoprotective effects in patients with diabetes mellitus (DM). However, the renal protective effect of SGLT2i in non-diabetic nephropathy patients has not been extensively demonstrated. In this systematic review and meta-analysis, we aimed to evaluate the renal protective effect and safety of SGLT2i in non-diabetic nephropathy patients.

METHODS

we searched for relevant clinically randomised controlled trials and analyzed the effects of SGLT2i on estimated glomerular filtration rate (eGFR), urinary albumin/creatinine ratio (UACR), and systolic blood pressure (SBP) and the incidence of adverse events in patients with non-diabetic nephropathy.

RESULTS

We collated and analysed clinical data from six groups of patients with nondiabetic nephropathy. It was found that the SGLT2i significantly delayed the decline in eGFR [MD = 1.35 ml/min/1.73 m2, 95% CI 0.84, 1.86), P < 0.0001]. Furthermore, the SGLT2i significantly reduced UACR [MD =  - 24.47% l, 95% CI (- 38.9, -10.04), P = 0.0009], and showed a greater decrease in SBP [MD =  - 4.13 mmHg, 95% CI (- 7.49, - 0.77), P = 0.02]. There was no significant difference in the incidence of adverse reactions between dapagliflozin/empagliflozin and the control group [OR = 1.14, 95% CI (0.88, 1.47), P = 0.33].

CONCLUSION

This study shows that SGLT2i help to delay the progression of non-diabetic kidney disease. Therefore, SGLT2i may contribute to the general treatment of nondiabetic nephropathy.

Excretion of glucose analogue with SGLT2 affinity predicts response effectiveness to sodium glucose transporter 2 inhibitors in patients with type 2 diabetes mellitus

PURPOSE

Sodium-glucose cotransporter 2 inhibitor (SGLT2i) regulation, developed as treatment for patients with type 2 diabetes, can be imaged with the glucose analogue alpha-methyl-4-deoxy-4-[18F]fluoro-D-glucopyranoside (Me4FDG), a positron emission tomography (PET) tracer with a high affinity for SGLT1 and SGLT2 proteins. With regard to therapy effectiveness, we aimed to investigate whether clinical parameters or Me4FDG excretion could predict response to SGLT2i in patients with type 2 diabetes.

METHODS

In a longitudinal, prospective study, 19 patients with type 2 diabetes underwent Me4FDG combined PET and magnetic resonance imaging (PET/MRI) scans at baseline and 2 weeks after initiation of therapy with SGLT2i, accompanied by the collection of blood and urine samples. Me4FDG-excretion was determined from the Me4FDG uptake in the bladder. Long-term response was determined by HbA1c level after 3 months; a strong response to the therapy was defined as a reduction of HbA1c by at least 10% from baseline.

RESULTS

SGLT2i resulted in significantly increased Me4FDG excretion (4.8 vs. 45.0, P < 0.001) and urine glucose (56 vs. 2806 mg/dl, P < 0.001). Baseline urine glucose and baseline Me4FDG excretion correlated both with long-term decline in HbA1c with r = 0.55 (P < 0.05). However, only Me4FDG excretion was a predictor of a strong response to SGLT2i (P = 0.005, OR 1.9).

CONCLUSIONS

Using Me4FDG-PET, we demonstrated for the first time renal SGLT2-related excretion before and after short-term SGLT2i treatment. In contrary to other clinical parameters, SGLT2-related excretion before treatment was a robust predictor of long-term HbA1c response in patients with type 2 diabetes, suggesting that therapy effectiveness is only dependent of endogenous SGLT2 processes.

Ex vivo confocal microscopy detects basic patterns of acute and chronic lesions using fresh kidney samples

BACKGROUND

Ex vivo confocal microscopy is a real-time technique that provides high-resolution images of fresh, non-fixed tissues, with an optical resolution comparable to conventional pathology. The objective of this study was to investigate the feasibility of using ex vivo confocal microscopy in fusion mode (FuCM) and the haematoxylin and eosin (H&E)-like digital staining that results for the analysis of basic patterns of lesion in nephropathology.

METHODS

Forty-eight renal samples were scanned in a fourth-generation ex vivo confocal microscopy device. Samples were subjected to confocal microscopy imaging and were then processed using conventional pathology techniques. Concordance between the techniques was evaluated by means of the percentage of agreement and the κ index.

RESULTS

Agreement between conventional microscopy and H&E-like digital staining was strong (κ = 0.88) in the evaluation of acute tubular damage and was substantial (κ = 0.79) in the evaluation of interstitial fibrosis, interstitial inflammation, arterial and arteriolar lesions. H&E-like digital staining also allows rapid identification of extracapillary proliferation (κ = 0.88), necrosis and segmental sclerosis (κ = .88) in the glomerular compartment, but the results reported here are limited because of the small number of cases with these glomerular findings.

CONCLUSIONS

FuCM proved to be as effective as conventional techniques in evaluating the presence of acute tubular necrosis and interstitial fibrosis changes, but in fresh tissue. The ease of acquisition of ex vivo confocal microscopy images suggests that FuCM may be useful for rapid evaluation of kidney biopsies and to restructure the clinical workflow in renal histopathology.

Emerging Role of Sodium-Glucose Co-Transporter 2 Inhibitors for the Treatment of Chronic Kidney Disease

Chronic kidney disease is one of the leading causes of morbidity and mortality in the Philippines. It is associated with a growing health burden as many patients progress to end-stage renal disease. Until recently, therapeutic options for the management of chronic kidney disease were limited. Sodium-glucose co-transporter 2 inhibitors offer an alternative therapeutic approach for patients with chronic kidney disease. Several trials have shown renal benefits with sodium-glucose co-transporter 2 inhibitors in patients with cardiovascular disease with and without type 2 diabetes and across a range of estimated glomerular filtration rate levels. In the Philippines, the sodium-glucose co-transporter 2 inhibitors dapagliflozin and canagliflozin are approved for the prevention of new and worsening nephropathy in type 2 diabetes. With emerging treatment options, an urgent need exists for guidance on the management of chronic kidney disease within the Philippines. In this review, we focus on the putative renal-protective mechanisms of sodium-glucose co-transporter 2 inhibitors, including effects on tubuloglomerular feedback, albuminuria, endothelial function, erythropoiesis, uric acid levels, renal oxygen demand, and hypoxia. Furthermore, we discuss the findings of recent large clinical trials using sodium-glucose co-transporter 2 inhibitors in patients with chronic kidney disease and diabetic kidney disease, summarize safety aspects, and outline the practical management of patients with chronic kidney disease in the Philippines.

Diet and Proteinuria: State of Art

Proteinuria is a broad term used to describe the pathological presence of proteins, including albumin, globulin, Bence-Jones protein, and mucoprotein in the urine. When persistent, proteinuria is a marker of kidney damage and represents a reliable predictor of the risk of progression of renal failure. Medical nutrition therapy is imperative for patients with proteinuria because it may slow the progression of renal disease. The aim of this review is to explore different nutritional approaches in the management of proteinuria and their influence on pathophysiological processes. As such, protein restriction is the main dietary intervention. Indeed, other management approaches are frequently used to reduce it regarding micro and macronutrients, but also the dietary style. Among these, the nutritional approach represents one of the most used and controversial interventions and the studies rarely take the form of randomized and controlled trials. With this work we aspire to analyze current clinical knowledge of how nutrition could influence proteinuria, potentially representing a useful tool in the management of proteinuric nephropathy.

Impact of dapagliflozin treatment on renal function and diuretics use in acute heart failure: a pilot study

OBJECTIVE

To determine the impact of sodium-dependent glucose type 2 cotransporter inhibitors on the renal function in acute heart failure.

METHODS

In a single-centre, controlled, randomised study, patients were prescribed dapagliflozin in addition to standard therapy, or were in receipt of standard therapy. The prespecified outcome was renal function deterioration; the secondary outcomes were the development of resistance to diuretics, weight loss, death during hospitalisation and the rehospitalisation or death for any reason within 30 days following discharge.

RESULTS

102 patients were included (73.4±11.7 years, 57.8% men). The average left ventricular ejection fraction was 44.9%±14.7%, the average N-terminal prohormone of brain natriuretic peptide (NT-proBNP) was 4706 (1757; 11 244) pg/mL, the average estimated glomerular filtration rate (eGFR) was 51.6±19.5 mL/min. eGFR decreased 48 hours after randomisation in the dapagliflozin group (-4.2 (-11.03; 2.28) mL/min vs 0.3 (-6; 6) mL/min; p=0.04) but did not differ between the groups on discharge (54.71±19.18 mL/min and 58.92±24.65 mL/min; p=0.36). The incidence of worsening renal function did not differ (34.4% vs 15.2%; p=0.07). In the dapagliflozin group, there was less tendency to increase the dose of loop diuretics (14% vs 30%; p=0.048), lower average doses of loop diuretics (78.46±38.95 mg/day vs 102.82±31.26 mg/day; p=0.001) and more significant weight loss (4100 (2950; 5750) g vs 3000 (1380; 4650) g; p=0.02). In-hospital mortality was 7.8% (4(8%) in the dapagliflozin and 4 (7.7%) in the control group (p=0.95). The number of deaths within 30 days following discharge in the dapagliflozin group and in the control group was 9 (19%) and 12 (25%), p=0.55; the number of rehospitalisations was 14 (29%) and 17 (35%), respectively (p=0.51).

CONCLUSION

The use of dapagliflozin was associated with a more pronounced weight loss and less need to increase diuretic therapy without significant deterioration of the renal function. Dapagliflozin did not improve the in-hospital and 30-day prognosis after discharge.

TRIAL REGISTRATION NUMBER

N04778787.

Can SGLT2 inhibitors answer unmet therapeutic needs in chronic kidney disease?

Chronic kidney disease (CKD) is a global health problem, affecting more than 850 million people worldwide. The number of patients receiving renal replacement therapy (dialysis or renal transplantation) has increased over the years, and it has been estimated that the number of people receiving renal replacement therapy will more than double from 2.618 million in 2010 to 5.439 million in 2030, with wide differences among countries. The main focus of CKD treatment has now become preserving renal function rather than replacing it. This is possible, at least to some extent, through the optimal use of multifactorial therapy aimed at preventing end-stage kidney disease and cardiovascular events. Sodium/glucose cotransporter 2 inhibitors (SGLT2i) reduce glomerular hypertension and albuminuria with beneficial effects on progression of renal damage in both diabetic and non-diabetic CKD. SGLT2 inhibitors also show great benefits in cardiovascular protection, irrespective of diabetes. Therefore, the use of these drugs will likely be extended to the whole CKD population as a new standard of care.

An Overview of the Cardiorenal Protective Mechanisms of SGLT2 Inhibitors

Sodium-glucose co-transporter 2 (SGLT2) inhibitors block glucose reabsorption in the renal proximal tubule, an insulin-independent mechanism that plays a critical role in glycemic regulation in diabetes. In addition to their glucose-lowering effects, SGLT2 inhibitors prevent both renal damage and the onset of chronic kidney disease and cardiovascular events, in particular heart failure with both reduced and preserved ejection fraction. These unexpected benefits prompted changes in treatment guidelines and scientific interest in the underlying mechanisms. Aside from the target effects of SGLT2 inhibition, a wide spectrum of beneficial actions is described for the kidney and the heart, even though the cardiac tissue does not express SGLT2 channels. Correction of cardiorenal risk factors, metabolic adjustments ameliorating myocardial substrate utilization, and optimization of ventricular loading conditions through effects on diuresis, natriuresis, and vascular function appear to be the main underlying mechanisms for the observed cardiorenal protection. Additional clinical advantages associated with using SGLT2 inhibitors are antifibrotic effects due to correction of inflammation and oxidative stress, modulation of mitochondrial function, and autophagy. Much research is required to understand the numerous and complex pathways involved in SGLT2 inhibition. This review summarizes the current known mechanisms of SGLT2-mediated cardiorenal protection.

Glomerular Biomechanical Stress and Lipid Mediators during Cellular Changes Leading to Chronic Kidney Disease

Hyperfiltration is an important underlying cause of glomerular dysfunction associated with several systemic and intrinsic glomerular conditions leading to chronic kidney disease (CKD). These include obesity, diabetes, hypertension, focal segmental glomerulosclerosis (FSGS), congenital abnormalities and reduced renal mass (low nephron number). Hyperfiltration-associated biomechanical forces directly impact the cell membrane, generating tensile and fluid flow shear stresses in multiple segments of the nephron. Ongoing research suggests these biomechanical forces as the initial mediators of hyperfiltration-induced deterioration of podocyte structure and function leading to their detachment and irreplaceable loss from the glomerular filtration barrier. Membrane lipid-derived polyunsaturated fatty acids (PUFA) and their metabolites are potent transducers of biomechanical stress from the cell surface to intracellular compartments. Omega-6 and ω-3 long-chain PUFA from membrane phospholipids generate many versatile and autacoid oxylipins that modulate pro-inflammatory as well as anti-inflammatory autocrine and paracrine signaling. We advance the idea that lipid signaling molecules, related enzymes, metabolites and receptors are not just mediators of cellular stress but also potential targets for developing novel interventions. With the growing emphasis on lifestyle changes for wellness, dietary fatty acids are potential adjunct-therapeutics to minimize/treat hyperfiltration-induced progressive glomerular damage and CKD.

Renoprotective effect of SGLT-2 inhibitors among type 2 diabetes patients with different baseline kidney function: a multi-center study

Background

To assess the effect of sodium glucose cotransporter-2 inhibitors (SGLT-2is) for type 2 diabetes on kidney outcomes stratified by patient baseline estimated glomerular filtration rate (eGFR) levels (i.e., eGFR ≤ 60, 60 < eGFR ≤ 90, and eGFR > 90 mL/min/1.73 m²).

Methods

Patients from three large healthcare delivery systems in Taiwan who had initiated SGLT-2is or other glucose-lowering drugs (oGLDs) between May 2016 and December 2017 were included. Main outcomes were the times to 30%, 40%, and 50% eGFR reduction after treatment initiation. One-to-one propensity score matching in the overall study cohort and in each eGFR subgroup between SGLT-2i and oGLD users was applied to ensure between-group comparability in baseline characteristics.

Results

There were 13,666 matched pairs of SGLT-2is and oGLD users in the overall cohort. While a sustained eGFR decline was revealed in oGLD-treated patients (mean values [standard errors] from 85.61 [0.43] to 82.49 [0.44] mL/min/1.73 m² during the 12 months after treatment initiation), the mean eGFR values of SGLT-2i users decreased in the first 3 months (85.68 [0.37] to 79.71 [0.41] mL/min/1.73 m²) but then improved and sustained until the end of follow-up. There were 2300, 5705, and 5509 matched SGLT-2i and oGLD users in the eGFR ≤ 60, 60 < eGFR ≤ 90, and eGFR > 90 subgroups, respectively. Using SGLT-2is versus oGLDs was significantly associated with slower eGFR declines; hazard ratios (HRs) were 0.51 (95% CI 0.37–0.69), 0.51 (0.37–0.70), and 0.47 (0.31–0.71) for 40% eGFR reduction in the eGFR ≤ 60, 60 < eGFR ≤ 90, and eGFR > 90 subgroups, respectively. The renoprotective effect of SGLT-2is versus oGLDs was confirmed in the outcomes of 30% and 50% eGFR reduction across the three eGFR subgroups.

Conclusions

This study supports the renoprotective benefit of real-world SGLT-2i use irrespective of patient baseline kidney function.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12933-021-01396-2.

Sodium-Glucose Co-transporter-2 Inhibitors and Nephroprotection in Diabetic Patients: More Than a Challenge

Diabetic nephropathy is the most common cause of end-stage renal disease worldwide. Control of blood glucose and blood pressure (BP) reduces the risk of developing this complication, but once diabetic nephropathy is established, it is then only possible to slow its progression. Sodium-glucose cotransporter-2 inhibitors (SGLT2is) are a novel class of oral hypoglycemic agents that increase urinary glucose excretion by suppressing glucose reabsorption at the renal proximal tubule. SGLT2is lower glycated hemoglobin (HbA1c) without increasing the risk of hypoglycemia, induce weight loss and improve various metabolic parameters including BP, lipid profile, albuminuria and uric acid. Several clinical trials have shown that SGLT2is (empagliflozin, dapagliflozin canagliflozin, and ertugliflozin) improve cardiovascular and renal outcomes and mortality in patients with type 2 diabetes. Effects of SGLT2is on the kidney can be explained by multiple pathways. SGLT2is may improve renal oxygenation and intra-renal inflammation thereby slowing the progression of kidney function decline. Additionally, SGLT2is are associated with a reduction in glomerular hyperfiltration, an effect which is mediated by the increase in natriuresis, the re-activation of tubule-glomerular feedback and independent of glycemic control. In this review, we will focus on renal results of major cardiovascular and renal outcome trials and we will describe direct and indirect mechanisms through which SGLT2is confer renal protection.

Clinical Implications of Estimated Glomerular Filtration Rate Dip Following Sodium-Glucose Cotransporter-2 Inhibitor Initiation on Cardiovascular and Kidney Outcomes

Background The frequency of the initial short-term decline in estimated glomerular filtration rate (eGFR), eGFR dip, following initiation of sodium-glucose cotransporter-2 inhibitors (SGLT2i) and its clinical implications in real-world practice are not clear. Methods and Results We built a cohort of 36 638 new users of SGLT2i and 209 025 new users of other antihyperglycemics. Inverse probability weighting was used to estimate the excess rate of eGFR dip, risk of the composite cardiovascular outcome of nonfatal myocardial infarction, nonfatal stroke, hospitalization for heart failure, or all-cause mortality, and risk of the composite kidney outcome of eGFR decline >50%, end-stage kidney disease, or all-cause mortality. In the first 6 months of therapy, compared with other antihyperglycemics, excess rates of eGFR dip >10% and eGFR dip >30% were 9.86 (95% CI: 8.83-11.00) and 1.15 (0.70-1.62) per 100 SGLT2i users, respectively. In mediation analyses that accounted for eGFR dipping, SGLT2i use was associated with reduced risk of cardiovascular and kidney outcomes (hazard ratio, 0.92 [0.84-0.99] and 0.78 [0.71-0.87], respectively); the magnitude of the association reduced by eGFR dipping was small for both outcomes. SGLT2i was associated with reduced risk of both outcomes in those with higher than average probability of eGFR dip >10% or 30%. Compared with discontinuation, continued use of SGLT2i at 6 months was associated with reduced risk of cardiovascular and kidney outcomes in those with no eGFR dip or eGFR dip ≤10%, in those with eGFR dip >10%, and in those with eGFR dip >30%. Conclusions The salutary association of SGLT2i with cardiovascular and kidney outcomes was maintained regardless of eGFR dipping; concerns about eGFR dipping should not preclude use, and occurrence of eGFR dip after SGLT2i initiation may not warrant discontinuation.

Nephroprotection by SGLT2i in CKD Patients: May It Be Modulated by Low-Protein Plant-Based Diets?

Sodium-glucose-transporter 2 inhibitors (SGLT2i) are a new class of anti-diabetic drugs that in large trials such as CREDENCE have shown also a reduction of glomerular hyperfiltration and albuminuria in type 2 diabetic patients. Hence, the interest toward SGLT2i is focused toward this potential nephroprotective effect, in order to reduce the progression to overt nephropathy, and it seems to be confirmed in the most recent DAPA-CKD trial. This is the reason why the indication for SGLT2i treatment has been extended to chronic kidney disease (CKD) patients with eGFR up to 30 ml/min, namely with CKD stage 1-3. In patients with CKD stage 3 to 5, the most recent KDIGO guidelines recommend low-protein diet and plant-based regimens to delay end-stage kidney disease (ESKD) and improve quality of life. Similarly to SGLT2i, low-protein diets exert renal-protective effects by reducing single nephron hyperfiltration and urinary protein excretion. Beyond the glomerular hemodynamic effects, both protein restriction and SGLT2i are able to restore autophagy and, through these mechanisms, they may exert protective effects on diabetic kidney disease. In this perspective, it is likely that diet may modulate the effect of SGLT2i in CKD patients. Unfortunately, no data are available on the outcomes of the association of SGLT2i and low-protein and/or vegan diets. It is therefore reasonable to investigate whether CKD patients receiving SGLT2i may have further advantages in terms of nephroprotection from the implementation of a low-protein and/or plant-based diet or whether this association does not result in an additive effect, especially in vascular nephropathies.