Canagliflozin Prevents Intrarenal Angiotensinogen Augmentation and Mitigates Kidney Injury and Hypertension in Mouse Model of Type 2 Diabetes Mellitus

Emerging horizons: clinical applications and multifaceted benefits of SGLT-2 inhibitors beyond diabetes

SGLT-2 inhibitors, initially developed for type 2 diabetes, demonstrate profound cardiorenal and metabolic benefits. This review synthesizes evidence from clinical trials and mechanistic studies to elucidate their roles in cardiovascular diseases, chronic kidney disease, and non-alcoholic fatty liver disease. Key findings include a notable reduction in cardiovascular death/heart failure hospitalization, a marked decrease in heart failure hospitalization risk, and significant improvements in renal and hepatic outcomes. Emerging mechanisms, such as autophagy induction, ketone utilization, and anti-inflammatory effects, underpin these benefits. Ongoing trials explore their potential in non-diabetic populations, positioning SGLT-2 inhibitors as transformative agents in multisystem disease management.

11. Chronic Kidney Disease and Risk Management: Standards of Care in Diabetes-2025

The American Diabetes Association (ADA) "Standards of Care in Diabetes" includes the ADA's current clinical practice recommendations and is intended to provide the components of diabetes care, general treatment goals and guidelines, and tools to evaluate quality of care. Members of the ADA Professional Practice Committee, an interprofessional expert committee, are responsible for updating the Standards of Care annually, or more frequently as warranted. For a detailed description of ADA standards, statements, and reports, as well as the evidence-grading system for ADA's clinical practice recommendations and a full list of Professional Practice Committee members, please refer to Introduction and Methodology. Readers who wish to comment on the Standards of Care are invited to do so at professional.diabetes.org/SOC.

SGLT2 inhibition and adipose tissue metabolism: current outlook and perspectives

Sodium-glucose co-transporter 2 inhibitors (SGLT2i) have emerged as important agents for the treatment of type 2 diabetes mellitus (T2DM). SGLT2 inhibitors have been associated with improved cardiovascular outcomes, not only through their immediate hemodynamic effects-such as glycosuria and (at least temporary) increased natriuresis-but also due to their multifaceted impact on metabolism. Recently, studies have also focused on the effects of SGLT2 inhibitors on adipose tissue. Aside from the well-documented effects on human adiposity, SGLT2i have shown, both in vitro and in murine models, the ability to reduce fat mass, upregulate genes related to browning of white adipose tissue, influence adipocyte size and fatty acid oxidation, and improve oxidative stress and overall metabolic health. In humans, even though data are still limited, recent evidence seems to confirm that the SGLT2i effects observed in cardiovascular outcome trials could be partially explained by their impact on adipose tissue. This review aims to clarify the impact of SGLT2i on adipose tissue, highlighting their role in metabolic health and their potential to transform treatment strategies for T2DM beyond glucose metabolism.

SGLT2-Inhibition in Patients With Alport Syndrome

Introduction

Large-scale trials showed positive outcomes of sodium-glucose cotransporter-2 inhibitors (SGLT2i) in adults with chronic kidney disease (CKD). Whether the use of SGLT2i is safe and effective in patients with the common hereditary CKD Alport syndrome (AS) has not yet been investigated specifically in larger cohorts.

Methods

This observational, multicenter, international study (NCT02378805) assessed 112 patients with AS after start of SGLT2i. The study's primary end point was change of albuminuria in albumin/g creatinine from the start of therapy.

Results

Compared to randomized trials investigating the effect of SGLT2i in CKD, the adult patients in this study were younger (aged 38 ± 14 years) and had a better estimated glomerular filtration rate (eGFR, 63 ± 35 ml/min per 1.73 m2; n = 98). Maximum follow-up was 32 months. Compared to baseline, at the first 3 follow-up visits (months 1 to 3, 4 to 8, and 9 to 15) after initiation of SGLT2i therapy, a significant reduction of albuminuria in mg albumin/g creatinine (>30%) was observed. Mean loss of eGFR was 9 ± 12 ml/min per 1.73 m2 almost 1 year after initiation of SGLT2i therapy (n = 35). At a total of 71 patient-years at risk, 0.24 adverse events (AEs) per patient-year on SGLT2i were reported.

Conclusion

This study indicates that, additive to renin-angiotensin system (RAS)-inhibition (RASi), SGLT2i have the potential to reduce the amount of albuminuria in patients with AS. Future studies are needed to investigate the long-term effects of SGLT2i on CKD progression in patients with AS to assess whether the observed reduction in albuminuria translates to a delay in kidney failure (KF).

A systematic review on effect of sodium-glucose cotransporter-2 inhibitors on the metabolic and endocrinological profile of patients with polycystic ovarian syndrome

BACKGROUND

Polycystic ovarian syndrome (PCOS) has been a common metabolic and endocrinal disorder, prevalent amongst women belonging to the reproductive age group. The aim of this systematic review was to assess the safety and efficacy profile of sodium-glucose cotransporter 2 (SGLT2) inhibitors (Canagliflozin, Dapagliflozin, Empagliflozin, and Licogliflozin) for the treatment of women suffering from PCOS.

METHODS

A literature search in PubMed, Science Direct, Cochrane Central Register of Controlled Trials, and ClinicalTrials.gov was conducted for randomized clinical trials of SGLT-2 inhibitors in PCOS patients by applying predetermined inclusion and exclusion criteria. The articles in English language were included.

RESULTS

Four randomized controlled trials including 146 subjects were included in the review. The clinical studies indicated a significant decrease in the levels of total testosterone, free androgen index, total body fat, homeostasis model assessment-estimated insulin resistance (HOMA-IR), body mass index (BMI), dehydroepiandrosterone sulfate (DHEAS) and fasting plasma glucose (FPG). However, no significant difference was reported in levels of sex hormone-binding globulin (SHBG). Overall, there was improvement in metabolic and endocrine profiles, suggesting a potentially beneficial impact of SGLT2 inhibitors in the management of PCOS.

CONCLUSION

There is a requirement for large extensive clinical trials to demonstrate the efficacy of SGLT-2 inhibitors in PCOS patients.

How do SGLT2 inhibitors protect the kidney? A mediation analysis of the EMPA-REG OUTCOME trial

INTRODUCTION

Mechanisms underlying kidney benefits with sodium-glucose cotransporter-2 (SGLT2) inhibition in heart failure and/or type 2 diabetes (T2D) with established cardiovascular disease are currently unclear.

METHODS

We evaluated post hoc the factors mediating the effect of empagliflozin on a composite kidney outcome (first sustained estimated glomerular filtration rate ≥40% reduction from baseline, initiation of renal replacement therapy or death due to kidney disease) in EMPA-REG OUTCOME (Empagliflozin Cardiovascular Outcome Event Trial in Type 2 Diabetes Mellitus Patients). Variables, calculated as change from baseline or updated mean, were evaluated as time-dependent covariates and using a landmark approach (at Week 12) in Cox regression analyses. In multivariable analyses, variables with the greatest mediating effect were added using a step-up procedure.

RESULTS

In univariable time-dependent updated mean covariate analyses, the strongest mediator was hematocrit (99.5% mediation). Hemoglobin, uric acid and urine albumin-to-creatinine ratio mediated 79.4%, 33.2% and 31.0%, respectively. Multivariable analyses were not performed due to the very strong mediation effect of hematocrit. In univariable Week 12 landmark change from baseline analyses, the strongest mediators included hematocrit (40.7%), glycated hemoglobin (28.3%), systolic blood pressure (16.8%) and free fatty acids (16.5%), which yielded a combined mediation of 78.9% in multivariable analysis.

CONCLUSIONS

Changes in hematocrit and hemoglobin were the strongest mediators of empagliflozin's kidney benefits in EMPA-REG OUTCOME participants with T2D and cardiovascular disease.

Evaluation of glucose-lowering medications in older people: a comprehensive systematic review and network meta-analysis of randomized controlled trials

BACKGROUND

Type 2 diabetes mellitus (T2DM) is increasingly being diagnosed in older adults. Our objective is to assess the advantages and potential drawbacks of different glucose-lowering medications in this specific population.

METHODS

A network meta-analysis was conducted to identify randomized controlled trials that examined patient-centered outcomes in adults aged ≥65 years with T2DM. We searched PubMed, Cochrane CENTRAL, and Embase up to September 23, 2023. Quality of eligible studies were assessed using the Cochrane RoB 2.0 tool.

RESULTS

A total of 22 trials that involved 41 654 participants were included, incorporating sodium-glucose cotransporter-2 (SGLT2) inhibitors, glucagon-like peptide-1 receptor agonists (GLP-1RAs), dipeptidyl peptidase-4 (DPP-4) inhibitors, metformin, sulfonylureas (SU) and acarbose. Our findings reveal that GLP-1RAs reduce the risk of major adverse cardiovascular events (risk ratio [RR], 0.83; 95% confidence interval [CI], 0.71 to 0.97) and body weight (mean difference [MD], -3.87 kg; 95% CI, -5.54 to -2.21). SGLT2 inhibitors prevent hospitalization for heart failure (RR, 0.66; 95% CI, 0.57 to 0.77), renal composite outcome (RR, 0.69; 95% CI, 0.53 to 0.89), and reduce body weights (MD, -1.85 kg; 95% CI, -2.42 to -1.27). SU treatment increases the risk of any hypoglycaemia (RR, 4.19; 95% CI, 3.52 to 4.99) and severe hypoglycaemia (RR, 7.06; 95% CI, 3.03 to 16.43). GLP-1RAs, SGLT2 inhibitors, metformin, SU and DPP-4 inhibitors are effective in reducing glycaemic parameters. Notably, the number of treatments needed decreases in most cases as age increases.

CONCLUSIONS

Novel glucose-lowering medications with benefits that outweigh risks should be prioritized for older patients with diabetes.

Canagliflozin Mitigated Cognitive Impairment in Streptozotocin-Induced Sporadic Alzheimer's Disease in Mice: Role of AMPK/SIRT-1 Signaling Pathway in Modulating Neuroinflammation

Sporadic Alzheimer's disease (SAD) represents a major health concern especially among elderly. Noteworthy, neuroinflammation and oxidative stress are highly implicated in AD pathogenesis resulting in enhanced disease progression. Moreover, most of the available anti-Alzheimer drugs have several adverse effects with variable efficacy, therefore new strategies, including agents with anti-inflammatory and antioxidant effects, are encouraged. Along these lines, canagliflozin (CAN), with its anti-inflammatory and anti-apoptotic activities, presents a promising candidate for AD treatment. Therefore, this study aimed to evaluate the therapeutic potential of CAN via regulation of AMPK/SIRT-1/BDNF/GSK-3β signaling pathway in SAD. SAD model was induced by intracerebroventricular streptozotocin injection (ICV-STZ;3 mg/kg, once), while CAN was administered (10 mg/kg/day, orally) to STZ-treated mice for 21 days. Behavioral tests, novel object recognition (NOR), Y-Maze, and Morris Water Maze (MWM) tests, histopathological examination, total adenosine monophosphate-activated protein kinase (T-AMPK) expression, p-AMPK, and silent information regulator-1 (SIRT-1) were evaluated. Furthermore, brain-derived neurotrophic factor (BDNF), glycogen synthase kinase-3β (GSK-3β), acetylcholinesterase (AChE), Tau protein, insulin-degrading enzyme (IDE), nuclear factor erythroid-2 (Nrf-2), interleukin-6 (IL-6), nuclear factor kappa-B-p65 (NFκB-p65), beta-site APP cleaving enzyme 1 (BACE-1), and amyloid beta (Aβ) plaque were assessed. CAN restored STZ-induced cognitive deficits, confirmed by improved behavioral tests and histopathological examination. Besides, CAN halted STZ-induced neurotoxicity through activation of p-AMPK/SIRT-1/BDNF pathway, subsequently reduction of GSK-3β, Tau protein, AChE, NFκB-p65, IL-6, BACE-1, and Aβ plaque associated with increased IDE and Nrf-2. Consequentially, our findings assumed that CAN, via targeting p-AMPK/SIRT-1 pathway, combated neuroinflammation and oxidative stress in STZ-induced AD. Thus, this study highlighted the promising effect of CAN for treating AD.

Systemic and organ-specific anti-inflammatory effects of sodium-glucose cotransporter-2 inhibitors

Inflammation plays an essential role and is a common feature in the pathogenesis of many chronic diseases. The exact mechanisms through which sodium-glucose cotransporter-2 (SGLT2) inhibitors achieve their much-acclaimed clinical benefits largely remain unknown. In this review, we detail the systemic and tissue- or organ-specific anti-inflammatory effects of SGLT2 inhibitors using evidence from animal and human studies. We discuss the potential pathways through which SGLT2 inhibitors exert their anti-inflammatory effects, including oxidative stress, mitochondrial, and inflammasome pathways. Finally, we highlight the need for further investigation of the extent of the contribution of the anti-inflammatory effects of SGLT2 inhibition to improvements in cardiometabolic and renal outcomes in clinical studies.

From inflammation to renal fibrosis: A one-way road in autoimmunity?

Renal fibrosis is now recognized as a main determinant of renal pathology to include chronic kidney disease. Deposition of pathological matrix in the walls of glomerular capillaries, the interstitial space, and around arterioles predicts and contributes to the functional demise of the nephron and its surrounding vasculature. The recent identification of the major cell populations of fibroblast precursors in the kidney interstitium such as pericytes and tissue-resident mesenchymal stem cells, or bone-marrow-derived macrophages, and in the glomerulus such as podocytes, parietal epithelial and mesangial cells, has enabled the study of the fibrogenic process thought the lens of involved immunological pathways. Besides, a growing body of evidence is supporting the role of the lymphatic system in modulating the immunological response potentially leading to inflammation and ultimately renal damage. These notions have moved our understanding of renal fibrosis to be recognized as a clinical entity and new main player in autoimmunity, impacting directly the management of patients.

Sodium-Glucose Cotransporter Protein 2 Inhibitors: Novel Application for the Treatment of Obesity-Associated Hypertension

Obesity is becoming increasingly prevalent in China and worldwide and is closely related to the development of hypertension. The pathophysiology of obesity-associated hypertension is complex, including an overactive sympathetic nervous system (SNS), activation of the renin-angiotensin-aldosterone system (RAAS), insulin resistance, hyperleptinemia, renal dysfunction, inflammatory responses, and endothelial function, which complicates treatment. Sodium-glucose cotransporter protein 2 (SGLT-2) inhibitors, novel hypoglycemic agents, have been shown to reduce body weight and blood pressure and may serve as potential novel agents for the treatment of obesity-associated hypertension. This review discusses the beneficial mechanisms of SGLT-2 inhibitors for the treatment of obesity-associated hypertension. SGLT-2 inhibitors can inhibit SNS activity, reduce RAAS activation, ameliorate insulin resistance, reduce leptin secretion, improve renal function, and inhibit inflammatory responses. SGLT-2 inhibitors can, therefore, simultaneously target multiple mechanisms of obesity-associated hypertension and may serve as an effective treatment for obesity-associated hypertension.

Neomangiferin, a Naturally Occurring Mangiferin Congener, Inhibits Sodium-Glucose Co-transporter-2: An In silico Approach

Type 2 diabetes is a major health concern contributing to most of diabetic cases worldwide. Mangiferin and its congeners are known for their diverse pharmacological properties. This study sought to investigate the inhibitory property of naturally occurring mangiferin congeners on sodium-glucose co-transporter 2 protein (SGLT-2) using comprehensive computational methods. The naturally occurring mangiferin congeners were subjected to molecular docking, molecular dynamics (MDs) simulation (100 ns), molecular mechanics Poisson-Boltzmann surface area (MM-PBSA) binding free energy, density functional theory calculations (B3LYP 6-31G basis set), and ADMET approaches to identify potential SGLT-2 inhibitor. The molecular docking studies revealed neomangiferin (-9.0 kcal/mol) as the hit molecule compared with dapagliflozin (-8.3 kcal/mol). Root-mean-square deviation (RMSD) and root-mean-square fluctuation (RMSF) plots from the MD simulations established that neomangiferin stabilizes SGLT-2 better than the dapagliflozin, a standard drug. The MM-PBSA binding free energy calculations showed that neomangiferin (-26.05 kcal/mol) elicited better binding affinity than dapagliflozin (-17.42 kcal/mol). The electronic studies showed that neomangiferin (3.48 eV) elicited high electrophilicity index compared with mangiferin (3.31 eV) and dapagliflozin (2.11 eV). Also, the ADMET properties showed that the hit molecule is safe when administered to diabetic subjects. The current in silico studies suggest that neomangiferin could emerge as a promising lead molecule as a SGLT-2 inhibitor.

11. Chronic Kidney Disease and Risk Management: Standards of Care in Diabetes-2024

The American Diabetes Association (ADA) "Standards of Care in Diabetes" includes the ADA's current clinical practice recommendations and is intended to provide the components of diabetes care, general treatment goals and guidelines, and tools to evaluate quality of care. Members of the ADA Professional Practice Committee, an interprofessional expert committee, are responsible for updating the Standards of Care annually, or more frequently as warranted. For a detailed description of ADA standards, statements, and reports, as well as the evidence-grading system for ADA's clinical practice recommendations and a full list of Professional Practice Committee members, please refer to Introduction and Methodology. Readers who wish to comment on the Standards of Care are invited to do so at professional.diabetes.org/SOC.

Why have SGLT2 Inhibitors Failed to Achieve the Desired Success in COVID-19?

The SARS-CoV-2 virus emerged towards the end of 2019 and caused a major worldwide pandemic lasting at least 2 years, causing a disease called COVID-19. SARS-CoV-2 caused a severe infection with direct cellular toxicity, stimulation of cytokine release, increased oxidative stress, disruption of endothelial structure, and thromboinflammation, as well as angiotensin-converting enzyme 2 (ACE2) down-regulation-mediated renin-angiotensin system (RAS) activation. In addition to glucosuria and natriuresis, sodium-glucose transport protein 2 (SGLT2) inhibitors (SGLT2i) cause weight loss, a decrease in glucose levels with an insulin-independent mechanism, an increase in erythropoietin levels and erythropoiesis, an increase in autophagy and lysosomal degradation, Na+/H+-changer inhibition, prevention of ischemia/reperfusion injury, oxidative stress and they have many positive effects such as reducing inflammation and improving vascular function. There was great anticipation for SGLT2i in treating patients with diabetes with COVID-19, but current data suggest they are not very effective. Moreover, there has been great confusion in the literature about the effects of SGLT2i on COVID-19 patients with diabetes . Various factors, including increased SGLT1 activity, lack of angiotensin receptor blocker co-administration, the potential for ketoacidosis, kidney injury, and disruptions in fluid and electrolyte levels, may have hindered SGLT2i's effectiveness against COVID-19. In addition, the duration of use of SGLT2i and their impact on erythropoiesis, blood viscosity, cholesterol levels, and vitamin D levels may also have played a role in their failure to treat the virus. This article aims to uncover the reasons for the confusion in the literature and to unravel why SGLT2i failed to succeed in COVID-19 based on some solid evidence as well as speculative and personal perspectives.

Sex-dependent effects of Canagliflozin on kidney protection in mice with combined hypertension-type 1 diabetes

Canagliflozin (CANA) is a sodium-glucose cotransporter 2 (SGLT2) inhibitor with blood glucose lowering effects. CANA also promotes kidney protection in patients with cardiovascular diseases and type 2 diabetes (T2D), as well as in normoglycemic patients with hypertension or heart failure. Clinical studies, although conduct in both sexes, do not report sex-dependent differences in T2DM treated with CANA. However, the impact of CANA in type 1 diabetes, as well in sex-dependent outcomes in such cohort needs further understanding. To analyze the effects of CANA in mice with combined hypertension and type 1 diabetes, diabetes was induced by STZ injection (5 days, 50mg/kg/day) in both male and female 8 weeks old genetic hypertensive mice (Lin), whereas the control (Lin) received 0.1M sodium citrate injections. 8 weeks after STZ. Mice were fed either regular or CANA-infused diet for 4 weeks. 8 weeks after STZ, hyperglycemia was present in both male and female mice. CANA reversed BG increase mice fed regular diet. Male LinSTZ mice had elevated water intake, urine output, urinary albumin to creatinine ratio (ACR), kidney lesion score, and creatinine clearance compared to the Lin control group. Kidney injury was improved in male LinSTZ + CANA group in male mice. Water intake and urine output were not statistically significantly different in female LinSTZ compared to female LinSTZ+ CANA. Moreover, CANA did not improve kidney injury in female mice, showing no effect in creatinine clearance, lesion score and fibrosis when compared to LinSTZ fed regular diet. Here we show that Canagliflozin might exert different kidney protection effects in male compared to female mice with hypertension and type 1 diabetes. Sex-dimorphisms were previously found in the pathophysiology of diabetes induced by STZ. Therefore, we highlight the importance of in-depth investigation on sex-dependent effects of CANA, taking in consideration the unique characteristics of disease progression for each sex.

A Transcriptome Array-Based Approach to Link SGLT-2 and Intrarenal Complement C5 Synthesis in Diabetic Nephropathy

Diabetic nephropathy is a common microvascular complication of diabetes mellitus. It is characterized by progressive chronic kidney disease (CKD) with decline of kidney function by hyperfiltration. On a mechanistic level, activation of the complement system has been implicated in the pathogenesis of diabetic nephropathy. Therefore, here we pursued a transcriptome array-based approach to link intrarenal SGLT-2 and the synthesis of distinct complement components in diabetic nephropathy. Publicly available datasets for SLC5A2 (encoding SGLT-2) and complement system components were extracted specifically from microdissected tubulointerstitial (healthy controls: n = 31, diabetic nephropathy: n = 17) and glomerular compartments (healthy controls: n = 21, diabetic nephropathy: n = 12). First, we compared tubulointerstitial and glomerular log2SLC5A2 mRNA expression levels and confirmed a predominant synthesis within the tubulointerstitial compartment. Among various complement components and receptors, the only significant finding was a positive association between SLC5A2 and the tubulointerstitial synthesis of the complement component C5 in diabetic nephropathy (p = 0.0109). Finally, intrarenal expression of SLC5A2 was associated predominantly with pathways involved in metabolic processes. Interestingly, intrarenal complement C5 synthesis was also associated with enrichment of metabolic signaling pathways, overlapping with SLC5A2 for "metabolism" and "biological oxidations". These observations could be of relevance in the pathogenesis of diabetic nephropathy and implicate a mechanistic link between SGLT-2 and intrarenal complement synthesis.

SGLT-2 inhibitors enhance the effect of metformin to ameliorate hormonal changes and inflammatory markers in a rat PCOS model

Polycystic ovary syndrome (PCOS) is a common endocrine, reproductive, and metabolic disorder affecting females. The management of PCOS is challenging and current interventions are not enough to deal with all consequences of this syndrome. We explored the beneficial effect of combined sodium glucose co transporter-2 inhibitor (SGLT-2i); (empagliflozin) and metformin on hormonal and metabolic parameters in an animal model of PCOS and insulin resistance (IR). Forty adult female Wistar rats divided into five groups: control, PCOS-IR, PCOS-IR treated with metformin, PCOS-IR treated with empagliflozin, and PCOS-IR treated with combined metformin and empagliflozin. Single modality treatment with metformin or empagliflozin yielded significant improvement in body mass index, insulin resistance, lipid profile, sex hormones, inflammatory markers, and ovarian cystic follicles. Combined metformin with empagliflozin expressed further significant improvement in sex hormones, inflammatory markers with disappearance of ovarian cystic follicles. The superior significant improvement with combined treatment over the single modality was in line with significant improvement in the ovarian AMPKα-SIRT1 expression.

A Role for Sodium-Glucose Cotransporter 2 Inhibitors in the Treatment of Chronic Kidney Disease: A Mini Review

BACKGROUND

Sodium-glucose cotransport protein 2 (SGLT2) inhibitors, a new type of glucose-lowering drug, have been well proved in several clinical studies for their glucose-lowering and nephroprotective effects, and the nephroprotective effects include both indirect effects of metabolic improvement and direct effects, independent of glucose-lowering effects.

SUMMARY

In patients with diabetic kidney disease (DKD), several studies have demonstrated the potential nephroprotective mechanisms of SGLT2 inhibitors, and evidence of nephroprotective mechanisms in the non-DKD population is accumulating. Although the nephroprotective mechanism of SGLT2 inhibitors has not been fully elucidated, several laboratory studies have illustrated the mechanism underlying the effects of SGLT2 inhibitors at various aspects.

KEY MESSAGES

The purpose of this article is to review the mechanism of nephroprotective effect of SGLT2 inhibitors and to look forward to promising research in the future.

A systematic review on renal effects of SGLT2 inhibitors in rodent models of diabetic nephropathy

We have performed a systematic review of studies reporting on the renal effects of SGLT2 inhibitors in rodent models of diabetes. In 105 studies, SGLT2 inhibitors improved not only the glycemic control but also various aspects of renal function in most cases. These nephroprotective effects were similarly reported whether treatment with the SGLT2 inhibitor started concomitant with the onset of diabetes (within 1 week), early after onset (1-4 weeks) or after nephropathy had developed (>4 weeks after onset) with the latter probably having the greatest translational value. They were observed across various animal models of type 1 and type 2 diabetes/obesity (4 and 23 models, respectively), although studies in the type 2 diabetes model of db/db mice more often had negative data than in other models. Among possibly underlying pathophysiological mechanisms of nephroprotection, treatment with SGLT2 inhibitors had beneficial effects on lipid metabolism, blood pressure, glomerulosclerosis as well as renal tubular fibrosis, apoptosis, oxidative stress, and inflammation. These pathomechanisms highly influence atherosclerosis and renal health, which are two major factors that lead to an enhanced mortality in patients with diabetes and/or chronic kidney disease. Interestingly, renal SGLT2 inhibitor effects did not always correlate with those on glucose homeostasis, particularly in a limited number of direct comparative studies with other anti-diabetic treatments, indicating that nephroprotection may at least partly occur by mechanisms other than improving glycemic control. Our analyses did not provide evidence for different nephroprotective efficacy between SGLT2 inhibitors. Importantly, only four of 105 studies reported on female animals, and none provided direct comparative data between sexes. We conclude that more data on female animals and more direct comparative studies with other anti-diabetic compounds and combinations of treatments are needed.

Slowing the Progression of Diabetic Kidney Disease

Diabetes is the most frequent cause of kidney disease that progresses to end-stage renal disease worldwide, and diabetic kidney disease is significantly related to unfavorable cardiovascular outcomes. Since the 1990s, specific therapies have emerged and been approved to slow the progression of diabetic kidney disease, namely, renin-angiotensin-aldosterone system blockers (including angiotensin-converting enzyme inhibitors (ACEi) angiotensin receptor blockers (ARBs), the non-steroidal mineralocorticoid receptor antagonist (NS-MRA), finerenone, and sodium-glucose cotransporter-2 (SGLT2) inhibitors). Mechanistically, these different classes of agents bring different anti-inflammatory, anti-fibrotic, and complementary hemodynamic effects to patients with diabetic kidney disease such that they have additive benefits on slowing disease progression. Within the coming year, there will be data on renal outcomes using the glucagon-like peptide-1 receptor agonist, semaglutide. All the aforementioned medications have also been shown to improve cardiovascular outcomes. Thus, all three classes (maximally dosed ACEi or ARB, low-dose SGLT-2 inhibitors, and the NS-MRA, finerenone) form the "pillars of therapy" such that, when used together, they maximally slow diabetic kidney disease progression. Ongoing studies aim to expand these pillars with additional medications to potentially normalize the decline in kidney function and reduce associated cardiovascular mortality.

Cardiorenal protective effects of canagliflozin in CREDENCE according to glucose lowering

INTRODUCTION

Relationships between glycemic-lowering effects of sodium glucose co-transporter 2 inhibitors and impact on kidney and cardiovascular outcomes are uncertain.

RESEARCH DESIGN AND METHODS

We analyzed 4395 individuals with prebaseline and postbaseline hemoglobin A1c (HbA1c) randomized to canagliflozin (n=2193) or placebo (n=2202) in The Canagliflozin and Renal Events in Diabetes with Established Nephropathy Clinical Evaluation trial. Effects on HbA1c were assessed using mixed models. Mediation of treatment effects by achieved glycemic control was analyzed using proportional hazards regression with and without adjustment for achieved HbA1c. End points included combined kidney or cardiovascular death, end-stage kidney disease or doubling of serum creatinine (primary trial outcome), and individual end point components.

RESULTS

HbA1c lowering was modified by baseline estimated glomerular filtration rate (eGFR). For baseline eGFR 60-90, 45-59, and 30-44 mL/min/1.73 m², overall HbA1c (canagliflozin vs placebo) decreased by -0.24%, -0.14%, and -0.08% respectively and likelihood of >0.5% decrease in HbA1c decreased with ORs of 1.47 (95% CI 1.27 to 1.67), 1.12 (0.94 to 1.33) and 0.99 (0.83 to 1.18), respectively. Adjustment for postbaseline HbA1c marginally attenuated canagliflozin effects on primary and kidney composite outcomes: unadjusted HR 0.67 (95% CI 0.57 to 0.80) and 0.66 (95% CI 0.53 to 0.81); adjusted for week 13 HbA1c, HR 0.71 (95% CI 0.060 to 0.84) and 0.68 (95% CI 0.55 to 0.83). Results adjusted for time-varying HbA1c or HbA1c as a cubic spline were similar and consistent with preserved clinical benefits across a range of excellent and poor glycemic control.

CONCLUSIONS

The glycemic effects of canagliflozin are attenuated at lower eGFR but effects on kidney and cardiac end points are preserved. Non-glycemic effects may be primarily responsible for the kidney and cardioprotective benefits of canagliflozin.22.

Canagliflozin retards age-related lesions in heart, kidney, liver, and adrenal gland in genetically heterogenous male mice

Canagliflozin (Cana), a clinically important anti-diabetes drug, leads to a 14% increase in median lifespan and a 9% increase in the 90th percentile age when given to genetically heterogeneous male mice from 7 months of age, but does not increase lifespan in female mice. A histopathological study was conducted on 22-month-old mice to see if Cana retarded diverse forms of age-dependent pathology. This agent was found to diminish incidence or severity, in male mice only, of cardiomyopathy, glomerulonephropathy, arteriosclerosis, hepatic microvesicular cytoplasmic vacuolation (lipidosis), and adrenal cortical neoplasms. Protection against atrophy of the exocrine pancreas was seen in both males and females. Thus, the extension of lifespan in Cana-treated male mice, which is likely to reflect host- or tumor-mediated delay in lethal neoplasms, is accompanied by parallel retardation of lesions, in multiple tissues, that seldom if ever lead to death in these mice. Canagliflozin thus can be considered a drug that acts to slow the aging process and should be evaluated for potential protective effects against many other late-life conditions.

Sodium-glucose cotransporter inhibitors and kidney fibrosis: review of the current evidence and related mechanisms

Sodium-glucose cotransporter inhibitors (SGLT2i) are a new class of anti-diabetic drugs that have beneficial cardiovascular and renal effects. These drugs decrease proximal tubular glucose reabsorption and decrease blood glucose levels as a main anti-diabetic action. Furthermore, SGLT2i decreases glomerular hyperfiltration by a tubuloglomerular feedback mechanism. However, the renal benefits of these agents are independent of glucose-lowering and hemodynamic factors, and SGLT2i also impacts the kidney structure including kidney fibrosis. Renal fibrosis is a common pathway and pathological marker of virtually every type of chronic kidney disease (CKD), and amelioration of renal fibrosis is of utmost importance to reduce the progression of CKD. Recent studies have shown that SGLT2i impact many cellular processes including inflammation, hypoxia, oxidative stress, metabolic functions, and renin-angiotensin system (RAS) which all are related with kidney fibrosis. Indeed, most but not all studies showed that renal fibrosis was ameliorated by SGLT2i through the reduction of inflammation, hypoxia, oxidative stress, and RAS activation. In addition, less known effects on SGLT2i on klotho expression, capillary rarefaction, signal transducer and activator of transcription signaling and peptidylprolyl cis/trans isomerase (Pin1) levels may partly explain the anti-fibrotic effects of SGLT2i in kidneys. It is important to remember that some studies have not shown any beneficial effects of SGLT2i on kidney fibrosis. Given this background, in the current review, we have summarized the studies and pathophysiologic aspects of SGL2 inhibition on renal fibrosis in various CKD models and tried to explain the potential reasons for contrasting findings.

The membrane-associated protein 17 (MAP17) is up-regulated in response to empagliflozin on top of RAS blockade in experimental diabetic nephropathy

Sodium-glucose cotransporter 2 inhibitors (SGLT2i) have proven to delay diabetic kidney disease (DKD) progression on top of the standard of care with the renin-angiotensin system (RAS) blockade. The molecular mechanisms underlying the synergistic effect of SGLT2i and RAS blockers is poorly understood. We gave a SGLT2i (empagliflozin), an angiotensin-converting enzyme inhibitor (ramipril), or a combination of both drugs for 8 weeks to diabetic (db/db) mice. Vehicle-treated db/db and db/m mice were used as controls. At the end of the experiment, mice were killed, and the kidneys were saved to perform a differential high-throughput proteomic analysis by mass spectrometry using isobaric tandem mass tags (TMT labeling) that allow relative quantification of the identified proteins. The differential proteomic analysis revealed 203 proteins differentially expressed in one or more experimental groups (false discovery rate < 0.05 and Log2 fold change ≥ ±1). Fourteen were differentially expressed in the kidneys from the db/db mice treated with empagliflozin with ramipril. Among them, MAP17 was up-regulated. These findings were subsequently validated by Western blot. The combined therapy of empagliflozin and ramipril up-regulated MAP17 in the kidney of a diabetic mice model. MAP17 is a major scaffolding protein of the proximal tubular cells that places transporters together, namely SGLT2 and NHE3. Our results suggest that SGLT2i on top of RAS blockade may protect the kidney by boosting the inactivation of NHE3 via the up-regulation of key scaffolder proteins such as MAP17.

11. Chronic Kidney Disease and Risk Management: Standards of Care in Diabetes-2023

The American Diabetes Association (ADA) "Standards of Care in Diabetes" includes the ADA's current clinical practice recommendations and is intended to provide the components of diabetes care, general treatment goals and guidelines, and tools to evaluate quality of care. Members of the ADA Professional Practice Committee, a multidisciplinary expert committee, are responsible for updating the Standards of Care annually, or more frequently as warranted. For a detailed description of ADA standards, statements, and reports, as well as the evidence-grading system for ADA's clinical practice recommendations and a full list of Professional Practice Committee members, please refer to Introduction and Methodology. Readers who wish to comment on the Standards of Care are invited to do so at professional.diabetes.org/SOC.

Obesity-associated cardiometabolic complications in polycystic ovary syndrome: The potential role of sodium-glucose cotransporter-2 inhibitors

Polycystic Ovary Syndrome (PCOS) is the most common endocrine disorder in reproductive-age women. PCOS is characterized by androgen excess, oligo/anovulation, and polycystic appearance of the ovaries. Women with PCOS have an increased prevalence of multiple cardiovascular risk factors such as insulin resistance, hypertension, renal injury, and obesity. Unfortunately, there is a lack of effective, evidence-based pharmacotherapeutics to target these cardiometabolic complications. Sodium-glucose cotransporter-2 (SGLT2) inhibitors provide cardiovascular protection in patients with and without type 2 diabetes mellitus. Although the exact mechanisms of how SGLT2 inhibitors confer cardiovascular protection remains unclear, numerous mechanistic hypotheses for this protection include modulation of the renin-angiotensin system and/or the sympathetic nervous system and improvement in mitochondrial function. Data from recent clinical trials and basic research show a potential role for SGLT2 inhibitors in treating obesity-associated cardiometabolic complications in PCOS. This narrative review discusses the mechanisms of the beneficial effect of SGLT2 inhibitors in cardiometabolic diseases in PCOS.

Pleiotropic effect of sodium-glucose cotransporter 2 inhibitors on blood pressure

Sodium-glucose cotransporter 2 (SGLT2) inhibitors have been incorporated as guideline-directed medical therapy for heart failure with reduced ejection fraction. Recent trials clearly established the efficacy of SGLT2 inhibitors on cardiac remodeling while preventing renal function decline in patients with or without diabetes mellitus. Blood pressure reduction during SGLT2 inhibitors use has been proposed through pleiotropic pathways and as a potential contributor that translates to cardiovascular benefits. The mechanisms underlying this decrease in blood pressure are not simply glycemic control. Orchestrating fluid status, modulation of sodium content and renin-angiotensin-activation system, anti-fibrosis and anti-inflammatory effect, ameliorating the characteristics of metabolic syndrome, as well as restoration of circadian rhythm all contributed to the BP lowering effect by SGLT2 inhibitors. Although SGLT2 inhibitors has not been demonstrated as anti-hypertensive agents thus far, their effects on BP alteration are clinically significant. In this review, we revisited the evidence correlating SGLT2 inhibitor use with blood pressure level. Future research directions will focus on the signaling pathway of SGLT2 inhibitors for fluid removal, atherosclerosis, vasoconstriction, and eventually hypertension.

The harmful intestinal microbial community accumulates during DKD exacerbation and microbiome-metabolome combined validation in a mouse model

OBJECTIVE

Diabetic kidney disease (DKD) is one of the most prevalent complications of diabetes mellitus (DM) and is associated with gut microbial dysbiosis. We aim to build a diagnostic model to aid clinical practice and uncover a crucial harmful microbial community that contributes to DKD pathogenesis and exacerbation.

DESIGN

A total of 528 fecal samples from 180 DKD patients and 348 non-DKD populations (138 DM and 210 healthy volunteers) from the First Affiliated Hospital of Zhengzhou University were recruited and randomly divided into a discovery phase and a validation phase. The gut microbial composition was compared using 16S rRNA sequencing. Then, the 180 DKD patients were stratified into four groups based on clinical stages and underwent gut microbiota analysis. We established DKD mouse models and a healthy fecal microbiota transplantation (FMT) model to validate the effects of gut microbiota on DKD and select the potential harmful microbial community. Untargeted metabolome-microbiome combined analysis of mouse models helps decipher the pathogenetic mechanism from a metabolic perspective.

RESULTS

The diversity of the gut microbiome was significantly decreased in DKD patients when compared with that of the non-DKD population and was increased in the patients with more advanced DKD stages. The DKD severity in mice was relieved after healthy gut microbiota reconstruction. The common harmful microbial community was accumulated in the subjects with more severe DKD phenotypes (i.e., DKD and DKD5 patients and DKD mice). The harmful microbial community was positively associated with the serum injurious metabolites (e.g., cholic acid and hippuric acid).

CONCLUSION

The fecal microbial community was altered markedly in DKD. Combining the fecal analysis of both human and animal models selected the accumulated harmful pathogens. Partially recovering healthy gut microbiota can relieve DKD phenotypes via influencing pathogens' effect on DKD mice's metabolism.

Genetic Deletion of AT1a Receptor or Na+/H+ Exchanger 3 Selectively in the Proximal Tubules of the Kidney Attenuates Two-Kidney, One-Clip Goldblatt Hypertension in Mice

The roles of angiotensin II (Ang II) AT1 (AT1a) receptors and its downstream target Na+/H+ exchanger 3 (NHE3) in the proximal tubules in the development of two-kidney, 1-clip (2K1C) Goldblatt hypertension have not been investigated previously. The present study tested the hypothesis that deletion of the AT1a receptor or NHE3 selectively in the proximal tubules of the kidney attenuates the development of 2K1C hypertension using novel mouse models with proximal tubule-specific deletion of AT1a receptors or NHE3. 2K1C Goldblatt hypertension was induced by placing a silver clip (0.12 mm) on the left renal artery for 4 weeks in adult male wild-type (WT), global Agtr1a−/−, proximal tubule (PT)-specific PT-Agtr1a−/− or PT-Nhe3−/− mice, respectively. As expected, telemetry blood pressure increased in a time-dependent manner in WT mice, reaching a maximal response by Week 3 (p < 0.01). 2K1C hypertension in WT mice was associated with increases in renin expression in the clipped kidney and decreases in the nonclipped kidney (p < 0.05). Plasma and kidney Ang II were significantly increased in WT mice with 2K1C hypertension (p < 0.05). Tubulointerstitial fibrotic responses were significantly increased in the clipped kidney (p < 0.01). Whole-body deletion of AT1a receptors completely blocked the development of 2K1C hypertension in Agtr1a−/− mice (p < 0.01 vs. WT). Likewise, proximal tubule-specific deletion of Agtr1a in PT-Agtr1a−/− mice or NHE3 in PT-Nhe3−/− mice also blocked the development of 2K1C hypertension (p < 0.01 vs. WT). Taken together, the present study provides new evidence for a critical role of proximal tubule Ang II/AT1 (AT1a)/NHE3 axis in the development of 2K1C Goldblatt hypertension.

Canagliflozin reverses Th1/Th2 imbalance and promotes podocyte autophagy in rats with membranous nephropathy

Idiopathic membranous nephropathy is the main cause of chronic kidney disease (CKD). Studies have shown sodium-glucose co-transporter 2 (SGLT2) inhibitors significantly delay renal outcomes in patients with CKD, but the exact mechanism remains unknown. In this study, we investigated the mechanism by which the SGLT2 inhibitor canagliflozin attenuates podocyte injury by reversing the imbalance in Helper T cell 1 (Th1)/Helper T cell 2 (Th2) in peripheral blood of rats with membranous nephropathy (MN). MN rats were gavaged with canagliflozin (10 mg/kg/d) and losartan (10 mg/kg/d), respectively, for eight weeks. Compared with the MN group, the urinary ratio of total protein and the creatinine levels of the canagliflozin group decreased significantly. Canagliflozin improved the glomerulus pathological damage, increased the expression levels of podocyte marker proteins. The protective effect of canagliflozin on kidneys was more obvious than that of losartan. Treatment with canagliflozin increased the proportion of Th1 cells by 2.3 times, decreased the proportion of Th2 cells by 68.5%, and significantly restrained the synthesis of immunoglobulin G1 in B-cells and glomerulus subepithelial immune complex deposition. Co-culture of B-cells derived from MN rats with podocytes triggered the activation of phosphorylation of mTOR and ULK1 of podocytes, inhibited podocyte autophagy and resulted in podocyte injury. B-cells derived from canagliflozin treatment rats reversed these effects above. In conclusion, canagliflozin exerts a protective effect on kidneys by reversing the imbalance in Th1/Th2 cells in MN rats and restoring the autophagy of podocytes inhibited by the abnormal immunoglobulin G secretion from B-cells.

Renal outcomes with sodium-glucose cotransporters 2 inhibitors

Diabetic nephropathy (DN) is one of the most serious complications of diabetes. Therefore, delaying and preventing the progression of DN becomes an important goal in the clinical treatment of type 2 diabetes mellitus. Recent studies confirm that sodium-glucose cotransporters 2 inhibitors (SGLT2is) have been regarded as effective glucose-lowering drugs with renal protective effect. In this review, we summarize in detail the present knowledge of the effects of SGLT2is on renal outcomes by analyzing the experimental data in preclinical study, the effects of SGLT2is on estimated glomerular flitration rates (eGFRs) and urinary albumin-creatinine ratios (UACRs) from clinical trials and observational studies, and renal events (such as renal death or renal failure requiring renal replacement therapy) in some large prospective cardiovaslucar outcomes trials. The underlying mechanisms for renoprotective activity of SGLT2is have been demondtrated in multiple diabetic and nondiabetic animal models including kidney-specific effects and secondary kidney effects related to amelioration in blood glucose and blood pressure. In conclusion, these promising results show that SGLT2is act beneficially in terms of the kidney for diabetic patients.

Sub-analyses of the DAPA-CKD study: new data on the use of sodium-glucose cotransporter type 2 inhibitor in the treatment of chronic kidney disease

Sodium-glucose cotransporter inhibitors updated their position in the therapy of patients with type 2 diabetes mellitus due to proven nephro- and cardioprotective effects. The DAPA-CKD study, performed among individuals with CKD of various etiologies, was also conducted in a mixed population, including patients without type 2 diabetes, showed the ability of dapagliflozin to reduce the risk of the primary combined endpoint (eGFR15 ml/min/1.73 m2, the need for chronic dialysis or kidney transplantation, time to renal or cardiovascular death), and certain secondary endpoints. Due to the inclusion of dapagliflozin into the treatment of the patients with CKD of not only the diabetic origin and the expected subsequent significant expansion of the patient population with indications for the use of this drug, the review of the results of the sub-analyses of DAPA-CKD study may be of interest to the clinicians.

Renin-a in the Subfornical Organ Plays a Critical Role in the Maintenance of Salt-Sensitive Hypertension

The brain renin-angiotensin system plays important roles in blood pressure and cardiovascular regulation. There are two isoforms of prorenin in the brain: the classic secreted form (prorenin/sREN) encoded by renin-a, and an intracellular form (icREN) encoded by renin-b. Emerging evidence indicates the importance of renin-b in cardiovascular and metabolic regulation. However, the role of endogenous brain prorenin in the development of salt-sensitive hypertension remains undefined. In this study, we test the hypothesis that renin-a produced locally in the brain contributes to the pathogenesis of hypertension. Using RNAscope, we report for the first time that renin mRNA is expressed in several regions of the brain, including the subfornical organ (SFO), the paraventricular nucleus of the hypothalamus (PVN), and the brainstem, where it is found in glutamatergic, GABAergic, cholinergic, and tyrosine hydroxylase-positive neurons. Notably, we found that renin mRNA was significantly elevated in the SFO and PVN in a mouse model of DOCA-salt–induced hypertension. To examine the functional importance of renin-a in the SFO, we selectively ablated renin-a in the SFO in renin-a–floxed mice using a Cre-lox strategy. Importantly, renin-a ablation in the SFO attenuated the maintenance of DOCA-salt–induced hypertension and improved autonomic function without affecting fluid or sodium intake. Molecularly, ablation of renin-a prevented the DOCA-salt–induced elevation in NADPH oxidase 2 (NOX2) in the SFO without affecting NOX4 or angiotensin II type 1 and 2 receptors. Collectively, our findings demonstrate that endogenous renin-a within the SFO is important for the pathogenesis of salt-sensitive hypertension.

New insights into the role of empagliflozin on diabetic renal tubular lipid accumulation

BACKGROUND

Glucose cotransporter (SGLT) 2 suppression provides potent renal protective effect during diabetic kidney disease (DKD). This work aimed to explore how empagliflozin (EMPA, the selective and strong inhibitor of SGLT2) affected renal lipid deposition among patients undergoing type 2 diabetes mellitus (T2DM), a T2DM mouse model and human renal proximal tubular epithelial (HK-2) cells.

METHODS

This work divided subjects as 3 groups: non-diabetic volunteers, patients treated with metformin and those treated with metformin plus EMPA. In an in vivo study, EMPA was adopted for treating db/db mice that were raised with the basal diet or the high-advanced glycation end products (AGEs) diet. In addition, AGEs and/or EMPA was utilized to treat HK-2 cells in vitro.

RESULTS

Results showed that diabetic patients treated with metformin plus EMPA had lower AGEs levels and renal fat fraction (RFF) than those treated with metformin. Moreover, a significant and positive association was found between AGEs and RFF. Results from the basic study showed that EMPA decreased cholesterol level, tubular lipid droplets, and protein levels related to cholesterol metabolism in AGEs-mediated HK-2 cells, kidneys of db/db mice and those fed with the high-AGEs diet. Additionally, EMPA decreased AGEs levels in serum while inhibiting the expression of receptor of AGEs (RAGE) in vitro and in vivo.

CONCLUSION

EMPA inhibited the AGEs-RAGE pathway, thereby alleviating diabetic renal tubular cholesterol accumulation.

Mitochondrial function and oxidative stress in white adipose tissue in a rat model of PCOS: effect of SGLT2 inhibition

Background

Polycystic ovary syndrome (PCOS), characterized by androgen excess and ovulatory dysfunction, is associated with a high prevalence of obesity and insulin resistance (IR) in women. We demonstrated that sodium–glucose cotransporter-2 inhibitor (SGLT2i) administration decreases fat mass without affecting IR in the PCOS model. In male models of IR, administration of SGLT2i decreases oxidative stress and improves mitochondrial function in white adipose tissue (WAT). Therefore, we hypothesized that SGLT2i reduces adiposity via improvement in mitochondrial function and oxidative stress in WAT in PCOS model.

Methods

Four-week-old female rats were treated with dihydrotestosterone for 90 days (PCOS model), and SGLT2i (empagliflozin) was co-administered during the last 3 weeks. Body composition was measured before and after SGLT2i treatment by EchoMRI. Subcutaneous (SAT) and visceral (VAT) WAT were collected for histological and molecular studies at the end of the study.

Results

PCOS model had an increase in food intake, body weight, body mass index, and fat mass/lean mass ratio compared to the control group. SGLT2i lowered fat mass/lean ratio in PCOS. Glucosuria was observed in both groups, but had a larger magnitude in controls. The net glucose balance was similar in both SGLT2i-treated groups. The PCOS SAT had a higher frequency of small adipocytes and a lower frequency of large adipocytes. In SAT of controls, SGLT2i increased frequencies of small and medium adipocytes while decreasing the frequency of large adipocytes, and this effect was blunted in PCOS. In VAT, PCOS had a lower frequency of small adipocytes while SGLT2i increased the frequency of small adipocytes in PCOS. PCOS model had decreased mitochondrial content in SAT and VAT without impacting oxidative stress in WAT or the circulation. SGLT2i did not modify mitochondrial function or oxidative stress in WAT in both treated groups.

Conclusions

Hyperandrogenemia in PCOS causes expansion of WAT, which is associated with decreases in mitochondrial content and function in SAT and VAT. SGLT2i increases the frequency of small adipocytes in VAT only without affecting mitochondrial dysfunction, oxidative stress, or IR in the PCOS model. SGLT2i decreases adiposity independently of adipose mitochondrial and oxidative stress mechanisms in the PCOS model.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13293-022-00455-x.

Androgen excess in PCOS model is associated with decreased markers of mitochondrial content in both subcutaneous and visceral white adipose tissue.

Androgen excess in PCOS model is associated with increased frequency of small adipocytes in subcutaneous white adipose tissue while decreasing frequency of small adipocytes in visceral white adipose tissue.

SGLT2 inhibition did not modify markers of mitochondrial content or oxidative stress in either subcutaneous or visceral white adipose tissue in PCOS model.

SGLT2 inhibition increased frequency of small adipocytes in both subcutaneous and visceral white adipose tissue in control rats; however, SGLT2 inhibition only increased frequency of small adipocytes in visceral white adipose tissue in PCOS model.

Immunosuppression by Mycophenolate Mofetil Mitigates Intrarenal Angiotensinogen Augmentation in Angiotensin II-Dependent Hypertension

Augmentation of intrarenal angiotensinogen (AGT) leads to further formation of intrarenal angiotensin II (Ang II) and the development of hypertensive kidney injury. Recent studies demonstrated that macrophages and the enhanced production of pro-inflammatory cytokines can be crucial mediators of renal AGT augmentation in hypertension. Accordingly, this study investigated the effects of immunosuppression by mycophenolate mofetil (MMF) on intrarenal AGT augmentation. Ang II (80 ng/min) was infused with or without daily administration of MMF (50 mg/kg) to Sprague-Dawley rats for 2 weeks. Mean arterial pressure (MAP) in Ang II infused rats was slightly higher (169.7 ± 6.1 mmHg) than the Ang II + MMF group (154.7 ± 2.0 mmHg), but was not statistically different from the Ang II + MMF group. MMF treatment suppressed Ang II-induced renal macrophages and IL-6 elevation. Augmentation of urinary AGT by Ang II infusion was attenuated by MMF treatment (control: 89.3 ± 25.2, Ang II: 1194 ± 305.1, and Ang II + MMF: 389 ± 192.0 ng/day). The augmentation of urinary AGT by Ang II infusion was observed before the onset of proteinuria. Elevated intrarenal AGT mRNA and protein levels in Ang II infused rats were also normalized by the MMF treatment (AGT mRNA, Ang II: 2.5 ± 0.2 and Ang II + MMF: 1.5 ± 0.1, ratio to control). Ang II-induced proteinuria, mesangial expansion and renal tubulointerstitial fibrosis were attenuated by MMF. Furthermore, MMF treatment attenuated the augmentation of intrarenal NLRP3 mRNA, a component of inflammasome. These results indicate that stimulated cytokine production in macrophages contributes to intrarenal AGT augmentation in Ang II-dependent hypertension, which leads to the development of kidney injury.

Kidney Angiotensin in Cardiovascular Disease: Formation and Drug Targeting

The concept of local formation of angiotensin II in the kidney has changed over the last 10-15 years. Local synthesis of angiotensinogen in the proximal tubule has been proposed, combined with prorenin synthesis in the collecting duct. Binding of prorenin via the so-called (pro)renin receptor has been introduced, as well as megalin-mediated uptake of filtered plasma-derived renin-angiotensin system (RAS) components. Moreover, angiotensin metabolites other than angiotensin II [notably angiotensin-(1-7)] exist, and angiotensins exert their effects via three different receptors, of which angiotensin II type 2 and Mas receptors are considered renoprotective, possibly in a sex-specific manner, whereas angiotensin II type 1 (AT1) receptors are believed to be deleterious. Additionally, internalized angiotensin II may stimulate intracellular receptors. Angiotensin-converting enzyme 2 (ACE2) not only generates angiotensin-(1-7) but also acts as coronavirus receptor. Multiple, if not all, cardiovascular diseases involve the kidney RAS, with renal AT1 receptors often being claimed to exert a crucial role. Urinary RAS component levels, depending on filtration, reabsorption, and local release, are believed to reflect renal RAS activity. Finally, both existing drugs (RAS inhibitors, cyclooxygenase inhibitors) and novel drugs (angiotensin receptor/neprilysin inhibitors, sodium-glucose cotransporter-2 inhibitors, soluble ACE2) affect renal angiotensin formation, thereby displaying cardiovascular efficacy. Particular in the case of the latter three, an important question is to what degree they induce renoprotection (e.g., in a renal RAS-dependent manner). This review provides a unifying view, explaining not only how kidney angiotensin formation occurs and how it is affected by drugs but also why drugs are renoprotective when altering the renal RAS. SIGNIFICANCE STATEMENT: Angiotensin formation in the kidney is widely accepted but little understood, and multiple, often contrasting concepts have been put forward over the last two decades. This paper offers a unifying view, simultaneously explaining how existing and novel drugs exert renoprotection by interfering with kidney angiotensin formation.

SGLT2 Inhibition in Type 1 Diabetes with Diabetic Kidney Disease: Potential Cardiorenal Benefits Can Outweigh Preventable Risk of Diabetic Ketoacidosis

PURPOSE OF REVIEW

The aim of this review is to summarize existing research investigating the use of sodium glucose cotransporter-2 (SGLT2) inhibitors in patients with type 1 diabetes mellitus (T1DM) while highlighting potential strategies to mitigate the risk of diabetic ketoacidosis (DKA).

RECENT FINDINGS

SGLT2 inhibitors have been studied in patients with T1DM in phase 3 clinical trials such as the inTandem, DEPICT, and EASE trials, which demonstrated consistent reductions in HbA1c. Secondary analyses of these trials have also reported potential kidney protective effects that are independent of improved glycemic control. However, trials in patients with type 2 diabetes mellitus (T2DM) have found an increased risk of DKA with SGLT2 inhibitors, a serious concern in patients with T1DM. SGLT2 inhibitors provide cardiovascular benefits and kidney protection in patients with T2DM and are a promising therapeutic option for patients with T1DM due to overlapping pathophysiological mechanisms. However, SGLT2 inhibitors increase the risk of DKA, and there is currently a lack of research investigating the beneficial effects of SGLT2 inhibitors in patients with T1DM. Preventative measure for DKA would have to be implemented and the risks would need to be carefully balanced with the benefits offered by SGLT2 inhibitors. Additional research will also be required to determine the kidney protective effects of SGLT2 inhibitors in patients with T1DM and diabetic kidney disease and to quantify the risk of DKA after the implementation of preventative measures, proper patient education, and ketone monitoring.

SGLT2 inhibition effect on salt-induced hypertension, RAAS, and Na+ transport in Dahl SS rats

Na+-glucose cotransporter-2 (SGLT2) inhibitors are the new mainstay of treatment for diabetes mellitus and cardiovascular diseases. Despite the remarkable benefits, the molecular mechanisms mediating the effects of SGLT2 inhibitors on water and electrolyte balance are incompletely understood. The goal of this study was to determine whether SGLT2 inhibition alters blood pressure and kidney function via affecting the renin-angiotensin-aldosterone system (RAAS) and Na+ channels/transporters along the nephron in Dahl salt-sensitive rats, a model of salt-induced hypertension. Administration of dapagliflozin (Dapa) at 2 mg/kg/day via drinking water for 3 wk blunted the development of salt-induced hypertension as evidenced by lower blood pressure and a left shift of the pressure natriuresis curve. Urinary flow rate, glucose excretion, and Na+- and Cl--to-creatinine ratios increased in Dapa-treated compared with vehicle-treated rats. To define the contribution of the RAAS, we measured various hormones. Despite apparent effects on Na+- and Cl--to-creatinine ratios, Dapa treatment did not affect RAAS metabolites. Subsequently, we assessed the effects of Dapa on renal Na+ channels and transporters using RT-PCR, Western blot analysis, and patch clamp. Neither mRNA nor protein expression levels of renal transporters (SGLT2, Na+/H+ exchanger isoform 3, Na+-K+-2Cl- cotransporter 2, Na+-Cl- cotransporter, and α-, β-, and γ-epithelial Na+ channel subunits) changed significantly between groups. Furthermore, electrophysiological experiments did not reveal any difference in Dapa treatment on the conductance and activity of epithelial Na+ channels. Our data suggest that SGLT2 inhibition in a nondiabetic model of salt-sensitive hypertension blunts the development of salt-induced hypertension by causing glucosuria and natriuresis without changes in the RAAS or the expression or activity of the main Na+ channels and transporters.NEW & NOTEWORTHY The present study indicates that Na+-glucose cotransporter-2 (SGLT2) inhibition in a nondiabetic model of salt-sensitive hypertension blunts the development and magnitude of salt-induced hypertension. Chronic inhibition of SGLT2 increases glucose and Na+ excretion without secondary effects on the expression and function of other Na+ transporters and channels along the nephron and hormone levels in the renin-angiotensin-aldosterone system. These data provide novel insights into the effects of SGLT2 inhibitors and their potential use in hypertension.

Role of Sodium-Glucose Co-Transporter 2 Inhibitors in the Regulation of Inflammatory Processes in Animal Models

Sodium-glucose co-transporter 2 inhibitors, also known as gliflozins, were developed as a novel class of anti-diabetic agents that promote glycosuria through the prevention of glucose reabsorption in the proximal tubule by sodium-glucose co-transporter 2. Beyond the regulation of glucose homeostasis, they resulted as being effective in different clinical trials in patients with heart failure, showing a strong cardio-renal protective effect in diabetic, but also in non-diabetic patients, which highlights the possible existence of other mechanisms through which gliflozins could be exerting their action. So far, different gliflozins have been approved for their therapeutic use in T2DM, heart failure, and diabetic kidney disease in different countries, all of them being diseases that have in common a deregulation of the inflammatory process associated with the pathology, which perpetuates and worsens the disease. This inflammatory deregulation has been observed in many other diseases, which led the scientific community to have a growing interest in the understanding of the biological processes that lead to or control inflammation deregulation in order to be able to identify potential therapeutic targets that could revert this situation and contribute to the amelioration of the disease. In this line, recent studies showed that gliflozins also act as an anti-inflammatory drug, and have been proposed as a useful strategy to treat other diseases linked to inflammation in addition to cardio-renal diseases, such as diabetes, obesity, atherosclerosis, or non-alcoholic fatty liver disease. In this work, we will review recent studies regarding the role of the main sodium-glucose co-transporter 2 inhibitors in the control of inflammation.

Improving the residual risk of renal and cardiovascular outcomes in diabetic kidney disease: A review of pathophysiology, mechanisms, and evidence from recent trials

Based on global estimates, almost 10% of adults have diabetes, of whom 40% are estimated to also have chronic kidney disease (CKD). Almost 2 decades ago, treatments targeting the renin-angiotensin system (RAS) were shown to slow the progression of kidney disease. More recently, studies have reported the additive benefits of antihyperglycaemic sodium-glucose co-transporter-2 inhibitors in combination with RAS inhibitors on both CKD progression and cardiovascular outcomes. However, these recent data also showed that patients continue to progress to kidney failure or die from kidney- or cardiovascular-related causes. Therefore, new agents are needed to address this continuing risk. Overactivation of the mineralocorticoid (MR) receptor contributes to kidney inflammation and fibrosis, suggesting that it is an appropriate treatment target in patients with diabetes and CKD. Novel, selective non-steroidal MR antagonists are being studied in these patients, and the results of two large recently completed clinical trials have shown that one such treatment, finerenone, significantly reduces CKD progression and cardiovascular events compared with standard of care. This review summarizes the pathogenic mechanisms of CKD in type 2 diabetes and examines the potential benefit of novel disease-modifying agents that target inflammatory and fibrotic factors in these patients.

Extending the ambit of SGLT2 inhibitors beyond diabetes: a review of clinical and preclinical studies on non-diabetic kidney disease

BACKGROUND

Sodium-glucose cotransporter-2 inhibitors (SGLT2i) are novel antidiabetic agents with overwhelming cardiorenal protection. Recent trials focusing on the nephroprotective role of SGLT2i have underscored its success as a phenomenal agent in halting the progression of kidney disease in patients with and without Type 2 diabetes mellitus. Multitudes of pleiotropic effects on tubules have raised hopes for reasonable nephroprotection beyond the purview of the hyperglycemic milieu.

AREA COVERED

This review summarizes various animal and human data as evidence for the utility of SGLT2i in non-diabetic chronic kidney disease (CKD). Web-based medical database entries were searched. On the premise of existing evidence, we have discussed mechanisms likely contributing to nephroprotection by SGLT2i in patients with non-diabetic CKD.

EXPERT OPINION

Further elucidation of mechanisms of nephroprotection offered by SGLT2i is required to extend its use as a nephroprotective agent. The use of non-traditional markers of kidney damage in future studies would improve the evaluation of their role in attenuating CKD progression. Emerging animal data support the early use of SGLT2i in states of modest proteinuria for superior outcomes. Future long-term trials in patients should aim to address the time of intervention with SGLT2i during the natural disease course of CKD for best outcomes.

11. Chronic Kidney Disease and Risk Management: Standards of Medical Care in Diabetes-2022

The American Diabetes Association (ADA) "Standards of Medical Care in Diabetes" includes the ADA's current clinical practice recommendations and is intended to provide the components of diabetes care, general treatment goals and guidelines, and tools to evaluate quality of care. Members of the ADA Professional Practice Committee, a multidisciplinary expert committee (https://doi.org/10.2337/dc22-SPPC), are responsible for updating the Standards of Care annually, or more frequently as warranted. For a detailed description of ADA standards, statements, and reports, as well as the evidence-grading system for ADA's clinical practice recommendations, please refer to the Standards of Care Introduction (https://doi.org/10.2337/dc22-SINT). Readers who wish to comment on the Standards of Care are invited to do so at professional.diabetes.org/SOC.

SGLT2 Inhibition for Cardiovascular Diseases, Chronic Kidney Disease, and NAFLD

Sodium glucose cotransporter 2 (SGLT-2) inhibitors are the latest class of antidiabetic medications. They prevent glucose reabsorption in the proximal convoluted tubule to decrease blood sugar. Several animal studies revealed that SGLT-2 is profoundly involved in the inflammatory response, fibrogenesis, and regulation of numerous intracellular signaling pathways. Likewise, SGLT-2 inhibitors markedly attenuated inflammation and fibrogenesis and improved the function of damaged organ in animal studies, observational studies, and clinical trials. SGLT-2 inhibitors can decrease blood pressure and ameliorate hypertriglyceridemia and obesity. Likewise, they improve the outcome of cardiovascular diseases such as heart failure, arrhythmias, and ischemic heart disease. SGLT-2 inhibitors are associated with lower cardiovascular and all-cause mortality as well. Meanwhile, they protect against nonalcoholic fatty liver disease (NAFLD), chronic kidney disease, acute kidney injury, and improve micro- and macroalbuminuria. SGLT-2 inhibitors can reprogram numerous signaling pathways to improve NAFLD, cardiovascular diseases, and renal diseases. For instance, they enhance lipolysis, ketogenesis, mitochondrial biogenesis, and autophagy while they attenuate the renin-angiotensin-aldosterone system, lipogenesis, endoplasmic reticulum stress, oxidative stress, apoptosis, and fibrogenesis. This review explains the beneficial effects of SGLT-2 inhibitors on NAFLD and cardiovascular and renal diseases and dissects the underlying molecular mechanisms in detail. This narrative review explains the beneficial effects of SGLT-2 inhibitors on NAFLD and cardiovascular and renal diseases using the results of latest observational studies, clinical trials, and meta-analyses. Thereafter, it dissects the underlying molecular mechanisms involved in the clinical effects of SGLT-2 inhibitors on these diseases.

Safety and efficacy of dapagliflozin in patients with focal segmental glomerulosclerosis: A prespecified analysis of the DAPA-CKD trial

Background

Despite renin–angiotensin–aldosterone system blockade and immunosuppressive treatment, focal segmental glomerulosclerosis (FSGS) often progresses to kidney failure. The objective of this prespecified analysis of the dapagliflozin and prevention of adverse outcomes in chronic kidney disease trial (DAPA-CKD) was to assess efficacy and safety of dapagliflozin in a small subgroup of participants with FSGS confirmed by kidney biopsy.

Methods

In DAPA-CKD, patients with an estimated glomerular filtration rate (eGFR) 25–75 mL/min/1.73 m² and urinary albumin:creatinine ratio (UACR) 200–5000 mg/g (22.6–565 mg/mol) were randomized to dapagliflozin 10 mg once daily or placebo as an adjunct to standard care and followed for median 2.4 years. The primary composite endpoint was sustained eGFR decline ≥50%, end-stage kidney disease, or kidney or cardiovascular death. The endpoint of interest for this analysis was eGFR slope (acute effects from baseline to Week 2 and chronic effects from Week 2 to end of treatment).

Results

Of 104 participants with biopsy-confirmed FSGS, 45 were randomized to dapagliflozin and 59 to placebo. Mean (standard deviation) age was 54.0 (14.3) years, mean eGFR 41.9 (11.5) mL/min/1.73 m² and median (interquartile range) UACR 1248 (749–2211) mg/g. The primary outcome occurred in 4 (8.9%) and 7 (11.9%) participants randomized to dapagliflozin and placebo, respectively [hazard ratio 0.62, 95% confidence interval (95% CI) 0.17, 2.17]. Dapagliflozin led to a larger acute reduction (standard error) in eGFR compared with placebo (−4.5, 95% CI −5.9 to −3.1 versus −0.9, −2.1 to 0.4 mL/min/1.73 m²/2 weeks). Thereafter, mean rates of chronic eGFR decline with dapagliflozin and placebo were −1.9 (−3.0, −0.9) and −4.0 (−4.9, −3.0) mL/min/1.73 m²/year, respectively (difference 2.0, 95% CI 0.6 to 3.5, mL/min/1.73 m²/year). Adverse events leading to study drug discontinuation were similar in both groups; there were fewer serious adverse events with dapagliflozin.

Conclusions

Among DAPA-CKD participants with FSGS, dapagliflozin reduced the rate of chronic decline of eGFR compared with placebo, although this difference was not statistically significant.

Deletion of heterogeneous nuclear ribonucleoprotein F in renal tubules downregulates SGLT2 expression and attenuates hyperfiltration and kidney injury in a mouse model of diabetes

AIMS/HYPOTHESIS

We previously reported that renal tubule-specific deletion of heterogeneous nuclear ribonucleoprotein F (Hnrnpf) results in upregulation of renal angiotensinogen (Agt) and downregulation of sodium-glucose co-transporter 2 (Sglt2) in Hnrnpf^RT knockout (KO) mice. Non-diabetic Hnrnpf^RT KO mice develop hypertension, renal interstitial fibrosis and glycosuria with no renoprotective effect from downregulated Sglt2 expression. Here, we investigated the effect of renal tubular Hnrnpf deletion on hyperfiltration and kidney injury in Akita mice, a model of type 1 diabetes.

METHODS

Akita Hnrnpf^RT KO mice were generated through crossbreeding tubule-specific (Pax8)-Cre mice with Akita floxed-Hnrnpf mice on a C57BL/6 background. Male non-diabetic control (Ctrl), Akita, and Akita Hnrnpf^RT KO mice were studied up to the age of 24 weeks (n = 8/group).

RESULTS

Akita mice exhibited elevated systolic blood pressure as compared with Ctrl mice, which was significantly higher in Akita Hnrnpf^RT KO mice than Akita mice. Compared with Akita mice, Akita Hnrnpf^RT KO mice had lower blood glucose levels with increased urinary glucose excretion. Akita mice developed kidney hypertrophy, glomerular hyperfiltration (increased glomerular filtration rate), glomerulomegaly, mesangial expansion, podocyte foot process effacement, thickened glomerular basement membranes, renal interstitial fibrosis and increased albuminuria. These abnormalities were attenuated in Akita Hnrnpf^RT KO mice. Treatment of Akita Hnrnpf^RT KO mice with a selective A1 adenosine receptor inhibitor resulted in an increase in glomerular filtration rate. Renal Agt expression was elevated in Akita mice and further increased in Akita Hnrnpf^RT KO mice. In contrast, Sglt2 expression was increased in Akita and decreased in Akita Hnrnpf^RT KO mice.

CONCLUSIONS/INTERPRETATION

The renoprotective effect of Sglt2 downregulation overcomes the renal injurious effect of Agt when these opposing factors coexist under diabetic conditions, at least partly via the activation of tubuloglomerular feedback.

Angiotensin II biphasically regulates cell differentiation in human iPSC-derived kidney organoids

Human kidney organoid technology holds promise for novel kidney disease treatment strategies and utility in pharmacological and basic science. Given the crucial roles of the intrarenal renin-angiotensin system (RAS) and angiotensin II (ANG II) in the progression of kidney development and injury, we investigated the expression of RAS components and effects of ANG II on cell differentiation in human kidney organoids. Human induced pluripotent stem cell-derived kidney organoids were induced using a modified 18-day Takasato protocol. Gene expression analysis by digital PCR and immunostaining demonstrated the formation of renal compartments and expression of RAS components. The ANG II type 1 receptor (AT1R) was strongly expressed in the early phase of organoid development (around day 0), whereas ANG II type 2 receptor (AT2R) expression levels peaked on day 5. Thus, the organoids were treated with 100 nM ANG II in the early phase on days 0-5 (ANG II-E) or during the middle phase on days 5-10 (ANG II-M). ANG II-E was observed to decrease levels of marker genes for renal tubules and proximal tubules, and the downregulation of renal tubules was inhibited by an AT1R antagonist. In contrast, ANG II-M increased levels of markers for podocytes, the ureteric tip, and the nephrogenic mesenchyme, and an AT2R blocker attenuated the ANG II-M-induced augmentation of podocyte formation. These findings demonstrate RAS expression and ANG II exertion of biphasic effects on cell differentiation through distinct mediatory roles of AT1R and AT2R, providing a novel strategy to establish and further characterize the developmental potential of human induced pluripotent stem cell-derived kidney organoids.NEW & NOTEWORTHY This study demonstrates angiotensin II exertion of biphasic effects on cell differentiation through distinct mediatory roles of angiotensin II type 1 receptor and type 2 receptor in human induced pluripotent stem cell-derived kidney organoids, providing a novel strategy to establish and further characterize the developmental potential of the human kidney organoids.

Renoprotective mechanisms of sodium-glucose co-transporter 2 (SGLT2) inhibitors against the progression of diabetic kidney disease

Sodium-glucose co-transporter 2 inhibitors (SGLT2-Is) have emerged as a promising class of antidiabetic drugs with cardioprotective and renoprotective effects in patients with type 2 diabetes (T2D). The sodium-glucose co-transporters 1 and 2 (SGLT 1 and SGLT2) located in the renal proximal tubules are responsible for glucose reabsorption from the glomerular filtrate back into the systemic circulation. Inhibition of SGLT2, which accounts for about 90% of the glucose reabsorption, leads to a significant reduction in blood glucose levels and a concomitant increase in the urinary excretion of glucose (glycosuria). Multiple mechanisms contribute to the nephroprotective effects of SGLT2-Is in T2D patients. These include: (1) Restoration of the tubuloglomerular feedback by increasing sodium delivery at macula densa, leading to afferent arteriolar constriction and reduced glomerular hyperfiltration, (2) Decreased activation of the intra-renal renin-angiotensin-aldosterone system, which also contributes to reducing glomerular hyperfiltration, (3) Increased production of ketone bodies, which serves as an alternate fuel for adenosine triphosphate production in mitochondria, which helps in attenuating inflammation, and (4) Protection against hypoxia, oxidative stress, and fibrosis. This review elaborates on the key mechanisms that underlie the nephroprotective effects and the adverse effects of SGLT2-Is in T2D patients with progressive diabetic kidney disease.

Acute Proteomic Changes in Non-human Primate Kidney after Partial-body Radiation with Minimal Bone Marrow Sparing

Near total body exposure to high-dose ionizing radiation results in organ-specific sequelae, including acute radiation syndromes and delayed effects of acute radiation exposure. Among these sequelae are acute kidney injury and chronic kidney injury. Reports that neither oxidative stress nor inflammation are dominant mechanisms defining radiation nephropathy inspired an unbiased, discovery-based proteomic interrogation in order to identify mechanistic pathways of injury. We quantitatively profiled the proteome of kidney from non-human primates following 12 Gy partial body irradiation with 2.5% bone marrow sparing over a time period of 3 wk. Kidney was analyzed by liquid chromatography-tandem mass spectrometry. Out of the 3,432 unique proteins that were identified, we found that 265 proteins showed significant and consistent responses across at least three time points post-irradiation, of which 230 proteins showed strong upregulation while 35 proteins showed downregulation. Bioinformatics analysis revealed significant pathway and upstream regulator perturbations post-high dose irradiation and shed light on underlying mechanisms of radiation damage. These data will be useful for a greater understanding of the molecular mechanisms of injury in well-characterized animal models of partial body irradiation with minimal bone marrow sparing. These data may be potentially useful in the future development of medical countermeasures.