Glomerular Hyperfiltration in Diabetes: Mechanisms, Clinical Significance, and Treatment

Molecular Mechanisms of SGLT2 Inhibitor on Cardiorenal Protection

The development of sodium-glucose transporter 2 inhibitor (SGLT2i) broadens the therapeutic strategies in treating diabetes mellitus. By inhibiting sodium and glucose reabsorption from the proximal tubules, the improvement in insulin resistance and natriuresis improved the cardiovascular mortality in diabetes mellitus (DM) patients. It has been known that SGLT2i also provided renoprotection by lowering the intraglomerular hypertension by modulating the pre- and post- glomerular vascular tone. The application of SGLT2i also provided metabolic and hemodynamic benefits in molecular aspects. The recent DAPA-CKD trial and EMPEROR-Reduced trial provided clinical evidence of renal and cardiac protection, even in non-DM patients. Therefore, the aim of the review is to clarify the hemodynamic and metabolic modulation of SGLT2i from the molecular mechanism.

Tenofovir disoproxil fumarate associated nephrotoxicity: a retrospective cohort study at two referral hospitals in Namibia

INTRODUCTION

The incidence and risk factors of tenofovir disoproxil fumarate (TDF)-related renal impairment (RI) in Namibia are unknown where TDF-containing ART regimens are used as the first line for HIV.

METHODOLOGY

A retrospective cohort study among HIV-infected patients at two intermediate hospitals. A decline in estimated glomerular filtration rate (eGFR) was significant if it was ≥25% and included a change to a lower eGFR stage. New-onset RI was defined as an eGFR <50 mL/min/1.73m² .

RESULTS

10 387 patients were included: 11.4% (n = 1182) experienced the decline in eGFR. Of these, 0.6% (n = 62) migrated to eGFR stages IV and V. The incidence was 4.5 (95% CI: 4.3-4.8) per 100 patient years. RI developed in 400 patients for an incidence rate of 2.4 (95% CI: 2.2-2.6) cases per 100 patient years. Risk factors with effect sizes >2.0, for decline-in-eGFR were baseline eGFR >60 (aHR = 15.6); hyperfiltration (aHR = 5.0); and pregnancy (aHR = 2.4); while for RI, they were hyperfiltration (aHR = 4.1) and pregnancy (aHR = 29).

CONCLUSION

The incidence of decline-in-eGFR was higher than in other sub-SSA countries, but not RI. A high baseline eGFR had the greatest risk for the decline, and hyperfiltration for the RI.

Making a case for the combined use of SGLT2 inhibitors and GLP1 receptor agonists for cardiorenal protection

Sodium glucose cotransporter-2 (SGLT2) inhibitors and glucagon-like peptide-1 receptor agonists (GLP-1RA) were initially approved to improve glycemic control in the treatment of type 2 diabetes. Clinical trials have also demonstrated beneficial effects with regards to cardiovascular and renal parameters. Beyond improving glycemic control, these therapies promote weight loss and lower blood pressure when used individually, and in an additive manner when used together. Accordingly, taking advantage of complementary mechanisms of action with the combined use of these two classes of agents to further improve cardiorenal outcomes is conceptually appealing, but has yet to be explored in detail in clinical trials. In this review, we discuss proposed mechanisms for renal protection, clinical benefits, and adverse events associated with the individual and combined use of SGLT2 inhibitors and GLP-1RA. The management of type 2 diabetes has significantly changed over the last few years, moving away from solely glycemic control towards the concurrent management of associated comorbidities in a patient population at significant risk of cardiovascular disease and progression of chronic kidney disease. It is from this perspective that we seek to outline the rationale for the sequential and/or combined use of SGLT2 inhibitors and GLP-1RA in patients with type 2 diabetes.

Nephroprotective effects of GLP-1 receptor agonists: where do we stand?

Glucagon-like peptide (GLP)-1 receptor agonists are the cornerstone in the treatment of hyperglycemia in many people suffering from type 2 diabetes (T2D). These drugs have potent glucose-lowering actions and, additionally, lower body weight through satiety induction while reducing blood pressure and dyslipidemia. Partly through these actions, GLP-1 receptor agonism was shown to reduce cardiovascular disease (CVD) in people with T2D with previous CVD or at high-risk thereof. In these cardiovascular safety trials, in secondary or exploratory analyses, GLP-1 receptor agonists were also shown to reduce macro-albuminuria, an accepted surrogate marker for diabetic kidney disease (DKD), a condition that still represents a major unmet medical need. In this review we will discuss the evidence which suggests renoprotection induced by GLP-1 receptor agonists and the potential mechanisms that may be involved. These include mitigation of hyperglycemia, overweight and insulin resistance, systemic and glomerular hypertension, dyslipidemia, sodium retention, inflammation and renal hypoxia. The recently initiated large-sized FLOW trial investigating the effects of semaglutide on hard renal outcomes in patients with DKD will provide clarity whether GLP-1 receptor agonists may reduce the burden of DKD in addition to their other beneficial metabolic and cardiovascular effects.

Rat pancreatectomy combined with isoprenaline or uninephrectomy as models of diabetic cardiomyopathy or nephropathy

Cardiovascular and renal complications are the predominant causes of morbidity and mortality amongst patients with diabetes. Development of novel treatments have been hampered by the lack of available animal models recapitulating the human disease. We hypothesized that experimental diabetes in rats combined with a cardiac or renal stressor, would mimic diabetic cardiomyopathy and nephropathy, respectively. Diabetes was surgically induced in male Sprague Dawley rats by 90% pancreatectomy (Px). Isoprenaline (Iso, 1 mg/kg, sc., 10 days) was administered 5 weeks after Px with the aim of inducing cardiomyopathy, and cardiac function and remodeling was assessed by echocardiography 10 weeks after surgery. Left ventricular (LV) fibrosis was quantified by Picro Sirius Red and gene expression analysis. Nephropathy was induced by Px combined with uninephrectomy (Px-UNx). Kidney function was assessed by measurement of glomerular filtration rate (GFR) and urine albumin excretion, and kidney injury was evaluated by histopathology and gene expression analysis. Px resulted in stable hyperglycemia, hypoinsulinemia, decreased C-peptide, and increased glycated hemoglobin (HbA1c) compared with sham-operated controls. Moreover, Px increased heart and LV weights and dimensions and caused a shift from α-myosin heavy chain (MHC) to β-MHC gene expression. Isoprenaline treatment, but not Px, decreased ejection fraction and induced LV fibrosis. There was no apparent interaction between Px and Iso treatment. The superimposition of Px and UNx increased GFR, indicating hyperfiltration. Compared with sham-operated controls, Px-UNx induced albuminuria and increased urine markers of kidney injury, including neutrophil gelatinase-associated lipocalin (NGAL) and podocalyxin, concomitant with upregulated renal gene expression of NGAL and kidney injury molecule 1 (KIM-1). Whereas Px and isoprenaline separately produced clinical endpoints related to diabetic cardiomyopathy, the combination of the two did not accentuate disease development. Conversely, Px in combination with UNx resulted in several clinical hallmarks of diabetic nephropathy indicative of early disease development.

Renal physiology of glucose handling and therapeutic implications

The rationale for using sodium-glucose cotransporter 2 (SGLT2) inhibitors in patients with type 2 diabetes (T2D) has evolved over the last decade. Due to the effects on glucosuria and body weight loss, SGLT2 inhibitors were originally approved for glycemic control in T2D. Since glucosuria is attenuated in chronic kidney disease (CKD) Stages 3–5, initial regulatory approval for SGLT2 inhibitor use was limited to patients with T2D and preserved estimated glomerular filtration rate. Over time, however, it has become increasingly apparent that these therapies have a variety of important pharmacodynamic and clinical effects beyond glycemic lowering, including antihypertensive and antialbuminuric properties, and the ability to reduce glomerular hypertension. Importantly, these sodium-related effects are preserved across CKD stages, despite attenuated glycemic effects, which are lost at CKD Stage 4. With the completion of cardiovascular (CV) outcome safety trials—EMPA-REG OUTCOME, CANVAS Program and DECLARE TIMI-58—in addition to reductions in CV events, SGLT2 inhibition consistently reduces hard renal endpoints. Importantly, these CV and renal effects are independent of glycemic control. Subsequent data from the recent CREDENCE trial—the first dedicated renal protection trial with SGLT-2 inhibition—demonstrated renal and CV benefits in albuminuric T2D patients, pivotal results that have expanded the clinical importance of these therapies. Ongoing trials will ultimately determine whether SGLT2 inhibition will have a role in renal protection in other clinical settings, including nondiabetic CKD and type 1 diabetes.

Sodium-coupled glucose transport, the SLC5 family, and therapeutically relevant inhibitors: from molecular discovery to clinical application

Sodium glucose transporters (SGLTs) belong to the mammalian solute carrier family SLC5. This family includes 12 different members in human that mediate the transport of sugars, vitamins, amino acids, or smaller organic ions such as choline. The SLC5 family belongs to the sodium symporter family (SSS), which encompasses transporters from all kingdoms of life. It furthermore shares similarity to the structural fold of the APC (amino acid-polyamine-organocation) transporter family. Three decades after the first molecular identification of the intestinal Na+-glucose cotransporter SGLT1 by expression cloning, many new discoveries have evolved, from mechanistic analysis to molecular genetics, structural biology, drug discovery, and clinical applications. All of these advances have greatly influenced physiology and medicine. While SGLT1 is essential for fast absorption of glucose and galactose in the intestine, the expression of SGLT2 is largely confined to the early part of the kidney proximal tubules, where it reabsorbs the bulk part of filtered glucose. SGLT2 has been successfully exploited by the pharmaceutical industry to develop effective new drugs for the treatment of diabetic patients. These SGLT2 inhibitors, termed gliflozins, also exhibit favorable nephroprotective effects and likely also cardioprotective effects. In addition, given the recent finding that SGLT2 is also expressed in tumors of pancreas and prostate and in glioblastoma, this opens the door to potential new therapeutic strategies for cancer treatment by specifically targeting SGLT2. Likewise, further discoveries related to the functional association of other SGLTs of the SLC5 family to human pathologies will open the door to potential new therapeutic strategies. We furthermore hope that the herein summarized information about the physiological roles of SGLTs and the therapeutic benefits of the gliflozins will be useful for our readers to better understand the molecular basis of the beneficial effects of these inhibitors, also in the context of the tubuloglomerular feedback (TGF), and the renin-angiotensin system (RAS). The detailed mechanisms underlying the clinical benefits of SGLT2 inhibition by gliflozins still warrant further investigation that may serve as a basis for future drug development.

High-protein diet: A barrier to the nephroprotective effects of sodium-glucose co-transporter-2 inhibitors?

Glomerular hyperfiltration is a common finding in patients with diabetes and poor glycaemic control; whole-kidney hyperfiltration, with glomerular filtration rate (GFR) values above normal, should be differentiated from single nephron hyperfiltration, consequent to nephron loss and compensatory hyperfiltration of the remnant nephrons. This is the result of an imbalance between the vascular tone of the afferent and efferent arterioles. Hormonal influences and/or an impaired tubuloglomerular feedback (TGF) system, because of excessive sodium (Na⁺ ) and glucose reabsorption in the proximal tubule, contribute to determine hyperfiltration. Sodium-glucose co-transporter-2 inhibitors (SGLT2is), by decreasing Na⁺ reabsorption and increasing the delivery of Na⁺ to the macula densa, lead to normalization of TGF, and, consequently, decrease GFR (both whole and single nephron). High-protein diets are popular among patients with type 1 and type 2 diabetes; importantly, 80% of the amino acids are also reabsorbed in the proximal tubule of the nephron and are transported by symporters that use the electro-chemical gradient of Na⁺ . Indeed, an acute protein load is associated with increased Na⁺ reabsorption and an increase in GFR. Here, we hypothesize that high-protein diets, by increasing Na⁺ reabsorption and GFR, may offset the positive renal effects of SGLT2is.

SGLT2 Inhibitors and Kidney Outcomes in Patients with Chronic Kidney Disease

Globally, diabetes mellitus is a leading cause of kidney disease, with a critical percent of patients approaching end-stage kidney disease. In the current era, sodium-glucose co-transporter 2 inhibitors (SGLT2i) have emerged as phenomenal agents in halting the progression of kidney disease. Positive effects of SGLT2i are centered on multiple mechanisms, including glycosuric effects, tubule-glomerular feedback, antioxidant, anti-fibrotic, natriuretic, and reduction in cortical hypoxia, alteration in energy metabolism. Concurrently, multiple kidney and cardiovascular outcome studies have reported remarkable advantages of SGLT2i including mortality benefits. Additionally, the superiority of combination therapies (SGLT2I along with metformin/DDP-4 Inhibitors) in treatment-naïve diabetic patients is further looked into with potential signal towards glycemic and blood pressure control. Reported promising results initiate a gateway for future research targeting kidney outcomes with combination therapies as an initial approach. In the current paper, we summarize leading cardiovascular and kidney outcome trials in patients with type 2 diabetes, the role of SGLT2i in non-diabetic proteinuric kidney disease, and the potential mechanisms of action of SGLT2i with special focus on combination therapy as an initial therapeutic approach in treatment-naïve diabetic patients.

Podocytopathies

Podocytopathies are kidney diseases in which direct or indirect podocyte injury drives proteinuria or nephrotic syndrome. In children and young adults, genetic variants in >50 podocyte-expressed genes, syndromal non-podocyte-specific genes and phenocopies with other underlying genetic abnormalities cause podocytopathies associated with steroid-resistant nephrotic syndrome or severe proteinuria. A variety of genetic variants likely contribute to disease development. Among genes with non-Mendelian inheritance, variants in APOL1 have the largest effect size. In addition to genetic variants, environmental triggers such as immune-related, infection-related, toxic and haemodynamic factors and obesity are also important causes of podocyte injury and frequently combine to cause various degrees of proteinuria in children and adults. Typical manifestations on kidney biopsy are minimal change lesions and focal segmental glomerulosclerosis lesions. Standard treatment for primary podocytopathies manifesting with focal segmental glomerulosclerosis lesions includes glucocorticoids and other immunosuppressive drugs; individuals not responding with a resolution of proteinuria have a poor renal prognosis. Renin-angiotensin system antagonists help to control proteinuria and slow the progression of fibrosis. Symptomatic management may include the use of diuretics, statins, infection prophylaxis and anticoagulation. This Primer discusses a shift in paradigm from patient stratification based on kidney biopsy findings towards personalized management based on clinical, morphological and genetic data as well as pathophysiological understanding.

Impact of chronic kidney disease definition on assessment of its incidence and risk factors in patients with newly diagnosed type 1 and type 2 diabetes in the UK: A cohort study using primary care data from the United Kingdom

AIM

To estimate the incidence and risk factors of chronic kidney disease (CKD) in patients with newly-diagnosed diabetes using different CKD definitions.

METHODS

Using UK primary care data, patients with diabetes (type 1, 4691; type 2, 109,365) and no CKD were followed to identify newly-diagnosed CKD, classified by a broad and narrow CKD definition (to capture diabetes-induced CKD, termed diabetic kidney disease, DKD). Adjusted incidence rates of CKD/DKD were calculated, and risk factors identified using Cox regression.

RESULTS

There were 404 CKD cases and 147 DKD cases among patients with type 1 diabetes (T1D), and 29,104 CKD cases, 9284 DKD cases among patients with type 2 diabetes (T2D). Adjusted incidence rates of CKD per 100 years were 5.4 (T1D) and 5.5 (T2D); for DKD they were 1.9 and 1.5, respectively. Risk factors for CKD/DKD were older age, high social deprivation, obesity, cardiovascular disease, hypertension and smoking. Poor glycaemic control in the year after diabetes diagnosis was a strong predictor of CKD/DKD occurrence beyond this first year, and a risk factor for CKD/DKD in T2D.

CONCLUSIONS

CKD and DKD remain common in diabetics in the decade after diagnosis. Early prevention of T2D and aggressive treatment of risk factors is urgent.

Clinical update: The important role of dual kidney function testing (ACR and eGFR) in primary care: Identification of risk and management in type 2 diabetes

Diabetic kidney disease (DKD) is common complication of type 1 and type 2 diabetes and may lead to progressive kidney dysfunction culminating in end-stage kidney disease. Kidney function is evaluated less frequently than other care procedures in patients with diabetes, even though the opportunity to identify DKD early and slow or even halt renal damage early in the disease progression represents a potentially important clinical opportunity for early intervention. The following review provides an overview of the under-recognised importance of kidney function in T2D and current best-practice to support the identification of DKD as part of primary care T2D management.

Nephroprotection by SGLT2 Inhibition: Back to the Future?

The introduction of sodium/glucose cotransporter 2 inhibitors (SGLT2i) has opened new perspectives for the management of diabetic population at risk of or with chronic kidney disease (CKD). More important, recent, large real-world studies have repositioned the nephroprotective efficacy of SGLT2i emerged from randomized trials within the frame of effectiveness. Furthermore, the salutary effects of these agents may extend to the nondiabetic population according to the positive results of current studies. Nevertheless, the clear benefits of these agents on the prevention of organ damage contrast with their unexpected, limited use in clinical practice. One potential barrier is the acute decline in glomerular filtration rate (GFR) commonly observed at the beginning of treatment. This phenomenon is reminiscent of the early response to the traditional nephroprotective interventions, namely blood pressure lowering, dietary protein and salt restriction and the inhibition of the renin–angiotensin system. Under this perspective, the “check-mark” sign observed in the GFR trajectory over the first weeks of SGT2i therapy should renew interest on the very basic goal of CKD treatment, i.e., alleviate hyperfiltration in viable nephrons in order to prolong their function.

Factors influencing blood pressure and microalbuminuria in children with type 1 diabetes mellitus: salt or sugar?

BACKGROUND

The aim of the study is to identify the effect of salt intake and diabetes itself on blood pressure (BP) profile and microalbuminuria in children with type one diabetes mellitus (T1DM). Our hypothesis is that higher amount of salt consumption and/or hyperglycemia may impair blood pressure pattern in children with T1DM.

METHODS

This cross-sectional study included 84 children and adolescents with T1DM (62% females, age 13.9 ± 3.2 years, disease duration 7.3 ± 3.1 years, 43% poorly controlled diabetes) and 54 aged- and sex-matched healthy children with an adequately collected 24-h urine samples. Urine sodium, creatinine, and microalbumin were measured and salt intake was assessed on the basis of sodium excretion in 24-h urine. Blood pressure profile of the children with T1DM was evaluated with 24-h ambulatory blood pressure monitoring.

RESULTS

Compared to the children with well-controlled diabetes, children with poorly controlled diabetes had significantly higher standard deviation scores (SDS) of nighttime systolic BP (0.22 ± 1.28 vs - 0.87 ± 0.76, p = 0.003) and lower dipping in diastole (13.4 ± 5.9 vs 18.4 ± 8.1, p = 0.046). Among T1DM group, children with the highest quartile of salt intake had higher nighttime systolic and diastolic BP-SDS (0.53 ± 1.25 vs - 0.55 ± 0.73, p = 0.002 and 0.89 ± 1.19 vs 0.25 ± 0.63, p = 0.038, respectively) and lower dipping in systole compared to their counterparts (7.7 ± 5.0 vs 11.5 ± 6.1, p = 0.040). High averaged HbA1c was independently associated with higher both daytime and nighttime systolic BP-SDS (p = 0.010, p < 0.001) and nighttime diastolic BP-SDS (p = 0.001), and lower diastolic dipping (p = 0.001). High salt intake was independently associated with higher nighttime systolic BP-SDS (p = 0.002) and lower systolic dipping (p = 0.019). A 24-h MAP-SDS was the only independent risk factor for microalbuminuria (p = 0.035).

CONCLUSION

Beside poor diabetic control, high salt consumption appears to be an important modifiable risk factor for impaired BP pattern, which contributes to the development of diabetic kidney disease in children with T1DM.

Renal hyperfiltration is independently associated with increased all-cause mortality in individuals with type 2 diabetes: a prospective cohort study

INTRODUCTION

In addition to favoring renal disease progression, renal 'hyperfiltration' has been associated with an increased risk of death, though it is unclear whether and how excess mortality is related to increased renal function. We investigated whether renal hyperfiltration is an independent predictor of death in patients with type 2 diabetes from the Renal Insufficiency And Cardiovascular Events Italian multicenter study.

RESEARCH DESIGN AND METHODS

This observational, prospective cohort study enrolled 15 773 patients with type 2 diabetes consecutively attending 19 Italian diabetes clinics in 2006-2008. Serum creatinine, albuminuria, cardiovascular risk factors, and complications/comorbidities were assessed at baseline. Vital status on 31 October 2015 was retrieved for 15 656 patients (99.26%). Patients were stratified (A) by absolute estimated glomerular filtration rate (eGFR) values in eGFR deciles or Kidney Disease: Improving Global Outcomes (KDIGO) categories and (B) based on age-corrected thresholds or age and gender-specific 95th and 5th percentiles in hyperfiltration, hypofiltration, and normofiltration groups.

RESULTS

The highest eGFR decile/category and the hyperfiltration group included (partly) different individuals with similar clinical features. Age and gender-adjusted death rates were significantly higher in deciles 1, 9, and 10 (≥103.9, 50.9-62.7, and <50.9 mL/min/1.73 m², respectively) versus the reference decile 3 (92.9-97.5 mL/min/1.73 m²). Mortality risk, adjusted for multiple confounders, was also increased in deciles 1 (HR 1.461 (95% CI 1.175 to 1.818), p=0.001), 9 (1.312 (95% CI 1.107 to 1.555), p=0.002), and 10 (1.976 (95% CI 1.673 to 2.333), p<0.0001) versus decile 3. Similar results were obtained by stratifying patients by KDIGO categories. Death rates and adjusted mortality risks were significantly higher in hyperfiltering and particularly hypofiltering versus normofiltering individuals.

CONCLUSIONS

In type 2 diabetes, both high-normal eGFR and hyperfiltration are associated with an increased risk of death from any cause, independent of confounders that may directly impact on mortality and/or affect GFR estimation. Further studies are required to clarify the nature of this relationship.

TRIAL REGISTRATION NUMBER

NCT00715481.

Comparison of mechanisms and transferability of outcomes of SGLT2 inhibition between type 1 and type 2 diabetes

Diabetes mellitus (DM) is a major chronic disease with ever-increasing prevalence and a variety of serious complications for persons with DM, such as cardiovascular and/or renal complications. New glucose-lowering therapies like DPP-4 inhibitors, GLP-1 receptor agonists, and SGLT-2 inhibitors have undergone cardiovascular outcome trials (CVOTs) for type 2 diabetes (T2DM), as by the guidance of the FDA. However, CVOTs for type 1 diabetes (T1DM) are generally lacking. Both, persons with T1DM and T2DM, are burdened with a high incidence of cardiovascular and renal disease such as atherosclerotic cardiovascular disease (ASCVD) and diabetic kidney disease (DKD). Although pathologies of the two types of diabetes cannot be compared, similar mechanisms and risk factors like sex, hyperglycaemia, hypertension, endothelial damage and (background) inflammation have been identified in the development of CVD and DKD in T1DM and T2DM. Recent CVOTs in T2DM demonstrated that SGLT-2 inhibitors, besides exerting a glucose-lowering effect, have beneficial effects on cardiovascular and renal mechanisms. These mechanisms are reviewed in detail in this manuscript and evaluated for possible transferability to, and thus efficacy in, T1DM. Our review of current literature suggests that SGLT-2 inhibitors have cardioprotective benefits beyond their glucose-lowering effects. As this mainly has been observed in CVOTs in T2DM, further investigation in the adjunctive therapy for type 1 diabetes is suggested.

Rationale and design of an investigator-initiated, multicenter, prospective open-label, randomized trial to evaluate the effect of ipragliflozin on endothelial dysfunction in type 2 diabetes and chronic kidney disease: the PROCEED trial

Background

Type 2 diabetes (T2D) is associated with renal impairment and vascular endothelial dysfunction. Therefore, this pathological connection is an important therapeutic target. Recent cardiovascular and renal outcome trials demonstrated that sodium glucose cotransporter 2 inhibitors (SGLT2is) consistently reduced the risks of cardiovascular and renal events and mortality in patients with T2D and various other background risks including chronic kidney disease (CKD). However, the precise mechanisms by which SGLT2is accords these therapeutic benefits remain uncertain. It is also unknown whether these SGLT2is-associated benefits are associated with the amelioration of endothelial dysfunction in patients with T2D and CKD.

Methods

The PROCEED trial is an investigator-initiated, prospective, multicenter, open-label, randomized-controlled trial. The target sample size is 110 subjects. After they furnish informed consent and their endothelial dysfunction is confirmed from their decreased reactive hyperemia indices (RHI), eligible participants with T2D (HbA1c, 6.0–9.0%) and established CKD (30 mL/min/1.73 m² ≤ estimated glomerular filtration ratio [eGFR] < 60 and/or ≥ urine albumin-to-creatinine ratio 30 mg/g Cr) will be randomized (1:1) to receive either 50 mg ipragliflozin daily or continuation of background treatment (non-SGLT2i). The primary endpoint is the change in RHI from baseline after 24 weeks. To compare the treatment effects between groups, the baseline-adjusted means and their 95% confidence intervals will be estimated by analysis of covariance adjusted for HbA1c (< 7.0% or ≥ 7.0%), age (< 70 y or ≥ 70 y), RHI (< 1.67 or ≥ 1.67), eGFR (< 45 mL/min/1.73 m² or ≥ 45 mL/min/1.73 m²), and smoking status. Prespecified responder analyses will be also conducted to determine the proportions of patients with clinically meaningful changes in RHI at 24 weeks.

Discussion

PROCEED is the first trial to examine the effects of ipragliflozin on endothelial dysfunction in patients with T2D and CKD. This ongoing trial will establish whether endothelial dysfunction is a therapeutic target of SGLT2is in this population. It will also provide deep insights into the potential mechanisms by which SGLT2is reduced the risks of cardiovascular and renal events in recent outcome trials.

Trial registration Unique Trial Number, jRCTs071190054 (https://jrct.niph.go.jp/en-latest-detail/jRCTs071190054).

Significance of SGLT2 inhibitors: lessons from renal clinical outcomes in patients with type 2 diabetes and basic researches

Diabetic kidney disease (DKD), a microvascular complication of diabetes, has been the leading cause of end-stage kidney disease (ESKD). Accordingly, patients with type 2 diabetes mellitus (T2DM) develop renal damage due to multiple metabolic and cardiorenal disease-related risk factors, including hyperglycemia, hypertension, dyslipidemia, hyperuricemia, and overnutrition/obesity. Despite multifactorial management including the administration of renin-angiotensin system inhibitors, patients often do not experience sufficient suppression of DKD progression and, thus, remain at risk for ESKD. Recent studies on cardiovascular outcomes among patients with T2DM have clearly shown that sodium-glucose cotransporter 2 (SGLT2) inhibitors, such as empagliflozin, canagliflozin, and dapagliflozin, have cardiorenal protective effects apart from their glucose-lowering effects. In particular, SGLT2 inhibitors have been found to improve renal outcomes, including ESKD, by slowing renal function decline and reducing urinary albumin excretion through their class effect. The proposed mechanisms for the renoprotective effects of SGLT2 inhibitors include the action of tubulo-glomerular feedback system and attenuation of hypoxia and metabolic stress in proximal tubular cells mediated through the inhibition of excessive glucose and sodium reabsorption, increased erythropoiesis, or increased ketone body production.

Effects of ertugliflozin on renal function over 104 weeks of treatment: a post hoc analysis of two randomised controlled trials

AIMS/HYPOTHESIS

This study aimed to evaluate the effect of ertugliflozin, a sodium-glucose cotransporter 2 (SGLT2) inhibitor, on eGFR and albuminuria (urine albumin/creatinine ratio [UACR]) vs glimepiride or placebo/glimepiride (non-ertugliflozin) over 104 weeks of treatment in participants with type 2 diabetes mellitus, using pooled data from two randomised controlled, active comparator studies from the eValuation of ERTugliflozin effIcacy and Safety (VERTIS) programme (Clinicaltrials.gov NCT01999218 [VERTIS SU] and NCT02033889 [VERTIS MET]). In the VERTIS SU study, ertugliflozin was evaluated vs glimepiride over 104 weeks. In the VERTIS MET study, ertugliflozin was evaluated vs placebo over 26 weeks; eligible participants were switched from placebo to blinded glimepiride from week 26 to week 104. The glycaemic efficacy of ertugliflozin vs non-ertugliflozin was also assessed in the pooled population.

METHODS

Post hoc, exploratory analysis was used to investigate mean changes from baseline in eGFR and UACR over 104 weeks.

RESULTS

Overall, mean (SD) baseline eGFR was 88.2 (18.8) ml min^-1 (1.73 m)^-2 and geometric mean (95% CI) of baseline UACR was 1.31 mg/mmol (1.23, 1.38). At week 6, the changes in eGFR from baseline were -2.3, -2.7 and -0.7 ml min^-1 (1.73 m)^-2 for the ertugliflozin 5 mg, ertugliflozin 15 mg and non-ertugliflozin groups, respectively. Mean eGFR in the ertugliflozin groups increased over time thereafter, while it decreased in the non-ertugliflozin group. Week 104 changes in eGFR from baseline were -0.2, 0.1 and -2.0 ml min^-1 (1.73 m)^-2 for the ertugliflozin 5 mg, ertugliflozin 15 mg and non-ertugliflozin groups, respectively. Among 415 patients (21.4% of the cohort) with albuminuria at baseline, the ertugliflozin groups had greater reductions in UACR at all measured time points up to week 104. At week 104, the non-ertugliflozin-corrected difference in UACR (95% CI) was -29.5% (-44.8, -9.8; p < 0.01) for ertugliflozin 5 mg and -37.6% (-51.8, -19.2; p < 0.001) for ertugliflozin 15 mg. Least squares mean changes from baseline in HbA_1c (mmol/mol [95% CI]) at week 104 were similar between treatment groups: -6.84 (-7.64, -6.03), -7.74 (-8.54, -6.94) and -6.84 (-7.65, -6.03) in the ertugliflozin 5 mg, ertugliflozin 15 mg and non-ertugliflozin groups, respectively. Least squares mean changes from baseline in HbA1_c (% [95% CI]) at week 104 were: -0.63 (-0.70, -0.55), -0.71 (-0.78, -0.64) and -0.63 (-0.70, -0.55) in the ertugliflozin 5 mg, ertugliflozin 15 mg and non-ertugliflozin groups, respectively.

CONCLUSIONS/INTERPRETATION

Ertugliflozin reduced eGFR at week 6, consistent with the known pharmacodynamic effects of SGLT2 inhibitors on renal function. Over 104 weeks, eGFR values returned to baseline and were higher with ertugliflozin compared with non-ertugliflozin treatment, even though changes in HbA_1c did not differ between the groups. Ertugliflozin reduced UACR in patients with baseline albuminuria.

TRIAL REGISTRATION

clinicaltrials.gov NCT01999218 and NCT02033889.

Cornea verticillata and acroparesthesia efficiently discriminate clusters of severity in Fabry disease

BACKGROUD

Fabry disease (OMIM #301 500), the most prevalent lysosomal storage disease, is caused by enzymatic defects in alpha-galactosidase A (GLA gene; Xq22.1). Fabry disease has historically been characterized by progressive renal failure, early stroke and hypertrophic cardiomyopathy, with a diminished life expectancy. A nonclassical phenotype has been described with an almost exclusive cardiac involvement. Specific therapies with enzyme substitution or chaperone molecules are now available depending on the mutation carried. Numerous clinical and fundamental studies have been conducted without stratifying patients by phenotype or severity, despite different prognoses and possible different pathophysiologies. We aimed to identify a simple and clinically relevant way to classify and stratify patients according to their disease severity.

METHODS

Based on data from the French Fabry Biobank and Registry (FFABRY; n = 104; 54 males), we applied unsupervised multivariate statistics to determine clusters of patients and identify clinical criteria that would allow an effective classification of adult patients. Thanks to these criteria and empirical clinical considerations we secondly elaborate a new score that allow the severity stratification of patients.

RESULTS

We observed that the absence of acroparesthesia or cornea verticillata is sufficient to classify males as having the nonclassical phenotype. We did not identify criteria that significantly cluster female patients. The classical phenotype was associated with a higher risk of severe renal (HR = 35.1; p <10-3) and cardiac events (HR = 4.8; p = 0.008) and a trend toward a higher risk of severe neurological events (HR = 7.7; p = 0.08) compared to nonclassical males. Our simple, rapid and clinically-relevant FFABRY score gave concordant results with the validated MSSI.

CONCLUSION

Acroparesthesia and cornea verticillata are simple clinical criteria that efficiently stratify Fabry patients, defining 3 different groups: females and males with nonclassical and classical phenotypes of significantly different severity. The FFABRY score allows severity stratification of Fabry patients.

Long-Term Safety and Efficacy of Sitagliptin for Type 2 Diabetes Mellitus in Japan: Results of a Multicentre, Open-Label, Observational Post-Marketing Surveillance Study

Introduction

A post-marketing surveillance (PMS) study was conducted to confirm the long-term risk–benefit profile of sitagliptin administered to Japanese patients with type 2 diabetes mellitus (T2DM) under real-world conditions.

Methods

This prospective, multicentre, open-label PMS collected data from 3326 patients receiving sitagliptin according to the approved indication during the case registration period (July 2010–June 2012; observation period, 3 years). Safety was assessed via collection of data on adverse drug reactions (ADRs), estimated glomerular filtration rate (eGFR) and cardiovascular events whereas efficacy was assessed via changes in glycated hemoglobin (HbA1c).

Results

In 3265 patients evaluated for safety, 270 ADRs occurred in 207 (6.3%) patients overall. Metabolism and nutrition disorders were the most common class of ADRs, occurring in 58 patients overall (53 non-serious, 5 serious) with hypoglycaemia (17 patients, 0.52%) the most common ADR. In patients with eGFR > 90 mL/min/1.73 m² at baseline (mean ± SD, 106.42 ± 18.11 mL/min/1.73 m², n = 584), eGFR declined by 11.83 ± 17.53 mL/min/1.73 m² (P < 0.0001; n = 360) over the observation period whereas eGFR appeared to be relatively maintained in patients with lower baseline eGFR levels. Cardiovascular events were infrequent [occurring in 4 of 84 (4.76%) patients at high cardiovascular risk] with no distinct features in this Japanese population and the cumulative incidence [8.42% (3.12–21.70) at 36 months; n = 32] was similar to that noted in previous studies involving sitagliptin. In patients evaluated for efficacy, the overall change in HbA1c from baseline to final evaluation was mean ± SD − 0.68 ± 1.34% (P < 0.0001, n = 2070). Reductions in HbA1c tended to be greater in younger patients and patients with higher body mass index (BMI) and HbA1c values at the start of administration.

Conclusion

Long-term sitagliptin administration in the routine clinical practice setting is associated with good efficacy, including as monotherapy, with no additional safety concerns.

Electronic supplementary material

The online version of this article (10.1007/s12325-020-01293-2) contains supplementary material, which is available to authorized users.

Initial Estimated Glomerular Filtration Rate Decline and Long-Term Renal Function During Intensive Antihypertensive Therapy: A Post Hoc Analysis of the SPRINT and ACCORD-BP Randomized Controlled Trials

Lowering blood pressure (BP) can lead to an initial decline in estimated glomerular filtration rate (eGFR). However, there is debate how much eGFR decline is acceptable. We performed a post hoc analysis of ACCORD-BP (Action to Control Cardiovascular Risk in Diabetes-Blood Pressure) and SPRINT (Systolic Blood Pressure Intervention Trial), which randomized patients to intensive or standard systolic BP-targets. We determined the relation between initial decline in mean arterial pressure and eGFR. Subsequently, we stratified patients to BP-target and initial eGFR decrease and assessed the relation with annual eGFR decline after 1 year. A total of 13 266 patients with 41 126 eGFR measurements were analyzed. Up to 10 mm Hg of BP-lowering, eGFR did not change. Hereafter, there was a linear decrease of 3.4% eGFR (95% CI, 2.9%-3.9%) per 10 mm Hg mean arterial pressure decrease. The observed eGFR decline based on 95% of the subjects varied from 26% after 0 mm Hg to 46% with a 40 mm Hg mean arterial pressure decrease. There was no difference in eGFR slope (P=0.37) according to initial eGFR decline and BP-target, with a decrease of 1.24 (95% CI, 1.09-1.39), 1.20 (95% CI, 0.97-1.43), and 1.14 (95% CI, 0.77-1.50) in the 5%, 5% to 20%, and >20% stratum during intensive and 0.95 (95% CI, 0.81-1.09), 1.23 (95% CI, 0.97-1.49), and 1.17 (95% CI, 0.65-1.69) mL/minute per 1.73 m2 per year during standard treatment. In patients at high cardiovascular risk with and without diabetes mellitus, we found no association between initial eGFR and annual eGFR decline during BP-lowering treatment. Our results support that an eGFR decrease up to 20% after BP lowering can be accepted and suggest that the limit can be extended up to 46% depending on the achieved BP reduction. Registration- URL: https://www.clinicaltrials.gov; Unique identifier: NCT00000620, NCT01206062.

Estimated Glomerular Filtration Rate as a Risk Stratification Tool for Early Complications in Revision Total Hip and Knee Arthroplasty

BACKGROUND

Establishing an association between postoperative outcomes and the spectrum of renal function would allow for more informed decisions to manage surgical risks and improved patient-specific care. Estimated glomerular filtration rate (eGFR) can be calculated from standard prescreening measurements to gauge renal function. This work investigates the effect of eGFR, as a continuous and categorical variable, on mortality and major and minor complications in patients undergoing revision total knee and hip arthroplasty.

METHODS

25,056 patients having undergone revision total hip and knee arthroplasty from 2013 to 2016 were identified using the National Quality Improvement Program database. The investigated outcomes included 30-day mortality, major complications, and minor complications. Multivariate regression models were created to evaluate the effect of eGFR on the outcomes of interest. Multivariate spline regressions were generated to assess for nonlinear relationships between eGFR as a continuous variable and the outcomes.

RESULTS

Our study revealed that as eGFR decreased <60 mL/min/1.73 m², mortality (P = .0001), any major complication (P < .001), and any minor complication (P < .001) increased. Patients with eGFR 15-30 mL/min/1.73 m² had increased risk for mortality (P = .033). There was an increased risk for any major complication at an eGFR 30-60 and <15 mL/min/1.73 m², (P < .05). There was an increased risk of minor complications for those with hyperfiltration and <60 mL/min/1.73 m².

CONCLUSION

Patients with lower preoperative eGFR generally display an increased risk for complications after revision total hip and knee arthroplasty. Proper consideration should be given to this patient population before surgical intervention to allow for preventative measures to be taken to improve patient outcomes.

The role of renal hypoxia in the pathogenesis of diabetic kidney disease: a promising target for newer renoprotective agents including SGLT2 inhibitors?

Diabetic kidney disease is the most common cause of end-stage kidney disease and poses a major global health problem. Finding new, safe, and effective strategies to halt this disease has proven to be challenging. In part that is because the underlying mechanisms are complex and not fully understood. However, in recent years, evidence has accumulated suggesting that chronic hypoxia may be the primary pathophysiological pathway driving diabetic kidney disease and chronic kidney disease of other etiologies and was called the chronic hypoxia hypothesis. Hypoxia is the result of a mismatch between oxygen delivery and oxygen demand. The primary determinant of oxygen delivery is renal perfusion (blood flow per tissue mass), whereas the main driver of oxygen demand is active sodium reabsorption. Diabetes mellitus is thought to compromise the oxygen balance by impairing oxygen delivery owing to hyperglycemia-associated microvascular damage and exacerbate oxygen demand owing to increased sodium reabsorption as a result of sodium-glucose cotransporter upregulation and glomerular hyperfiltration. The resultant hypoxic injury creates a vicious cycle of capillary damage, inflammation, deposition of the extracellular matrix, and, ultimately, fibrosis and nephron loss. This review will frame the role of chronic hypoxia in the pathogenesis of diabetic kidney disease and its prospect as a promising therapeutic target. We will outline the cellular mechanisms of hypoxia and evidence for renal hypoxia in animal and human studies. In addition, we will highlight the promise of newer imaging modalities including blood oxygenation level-dependent magnetic resonance imaging and discuss salutary interventions such as sodium-glucose cotransporter 2 inhibition that (may) protect the kidney through amelioration of renal hypoxia.

Severe hyperbilirubinemia is associated with higher risk of contrast-related acute kidney injury following contrast-enhanced computed tomography

INTRODUCTION

Contrast-induced acute kidney injury (CI-AKI) is associated with high risks of morbidity and mortality. Hyperbilirubinemia might have some renal protection but with no clear cutoff value for protection. Related studies are typically on limited numbers of patients and only in conditions of vascular intervention.

METHODS

We performed this study to elucidate CI-AKI in patients after contrast-enhanced computed tomography (CCT). The outcomes were CI-AKI, dialysis and mortality. Patients were divided to three groups based on their serum levels of total bilirubin: ≤1.2 mg/dl, 1.3-2.0 mg/dl, and >2.0 mg/dl.

RESULTS

We enrolled a total of 9,496 patients who had received CCT. Patients with serum total bilirubin >2.0 mg/dl were associated with CI-AKI. Those undergoing dialysis had the highest incidence of PC-AKI (p<0.001). No difference was found between the two groups of total bilirubin ≤1.2 and 1.3-2.0 mg/dl. Patients with total bilirubin >2mg/dl were associated with CI-AKI (OR = 1.89, 1.53-2.33 of 95% CI), dialysis (OR = 1.40, 1.01-1.95 of 95% CI) and mortality (OR = 1.63, 1.38-1.93 of 95% CI) after adjusting for laboratory data and all comorbidities (i.e., cerebrovascular disease, coronary artery disease, peripheral arterial disease, and acute myocardial infarction, diabetes mellitus, hypertension, gastrointestinal bleeding, cirrhosis, peritonitis, ascites, hepatoma, shock lung and colon cancer). We concluded that total bilirubin level >2 mg/dl is an independent risk factor for CI-AKI, dialysis and mortality after CCT. These patients also had high risks for cirrhosis or hepatoma.

CONCLUSION

This is the first study providing evidence that hyperbilirubinemia (total bilirubin >2.0 mg/dl) being an independent risk factor for CI-AKI, dialysis and mortality after receiving CCT. Most patients with total bilirubin >2.0mg/dl had cirrhosis or hepatoma.

The New Biology of Diabetic Kidney Disease-Mechanisms and Therapeutic Implications

Diabetic kidney disease remains the most common cause of end-stage kidney disease in the world. Despite reductions in incidence rates of myocardial infarction and stroke in people with diabetes over the past 3 decades, the risk of diabetic kidney disease has remained unchanged, and may even be increasing in younger individuals afflicted with this disease. Accordingly, changes in public health policy have to be implemented to address the root causes of diabetic kidney disease, including the rise of obesity and diabetes, in addition to the use of safe and effective pharmacological agents to prevent cardiorenal complications in people with diabetes. The aim of this article is to review the mechanisms of pathogenesis and therapies that are either in clinical practice or that are emerging in clinical development programs for potential use to treat diabetic kidney disease.

Chronic kidney disease in type 2 diabetes: Implications for managing glycaemic control, cardiovascular and renal risk

This review examines the current literature relating to diabetes related kidney disease (DKD) and the optimal management of cardio-renal risk. DKD develops in approximately 40% of patients with type 2 diabetes mellitus. The mainstay of therapy is to reduce the progression of DKD by optimising hyperglycaemia, blood pressure, lipids and lifestyle. Evidence supports the role for renin-angiotensin system blockade in limiting the progression of DKD. Recent data from diabetes related cardiovascular outcome trials and renal specific trials have provided a novel insight on the additional benefits of sodium-glucose cotransporter-2 inhibitors (SGLT2i) in reducing the progression of DKD as well as cardiovascular risk. Lessons have been learnt from CREDENCE and there are expectations that DAPA-CKD and EMPA-KIDNEY will further support the benefits of SGLT2 inhibition in relation to DKD. As a consequence, international guidelines have been updated to reflect the positive benefits. In addition, novel steroidal mineralocorticoid receptor antagonists offer a potential role in future years. The review examines the current evidence and future approach to optimising outcomes for renal protection in patients with diabetes.

Association of Prediabetes With CKD Progression and Adverse Cardiovascular Outcomes: An Analysis of the CRIC Study

PURPOSE

Despite our understanding of diabetes as an established risk factor for progressive kidney disease and cardiac complications, the prognostic significance of prediabetes in patients with chronic kidney disease (CKD) remains largely unknown.

METHODS

Participants of the Chronic Renal Insufficiency Cohort (CRIC) were categorized as having normoglycemia, prediabetes, or diabetes according to fasting plasma glucose, glycated hemoglobin A1c (HbA1c), and treatment with antidiabetic drugs at baseline. Unadjusted and adjusted proportional hazards models were fit to estimate the association of prediabetes and diabetes (versus normoglycemia) with: (1) composite renal outcome (end-stage renal disease, 50% decline in estimated glomerular filtration rate to ≤ 15 mL/min/1.73 m2, or doubling of urine protein-to-creatinine ratio to ≥ 0.22 g/g creatinine); (2) composite cardiovascular (CV) outcome (congestive heart failure, myocardial infarction or stroke); and (3) all-cause mortality.

RESULTS

Of the 3701 individuals analyzed, 945 were normoglycemic, 847 had prediabetes and 1909 had diabetes. The median follow-up was 7.5 years. Prediabetes was not associated with the composite renal outcome (adjusted hazard ratio [aHR] 1.13; 95% confidence interval [CI], 0.96-1.32; P = 0.14), but was associated with proteinuria progression (aHR 1.23; 95% CI, 1.03-1.47; P = 0.02). Prediabetes was associated with a higher risk of the composite CV outcome (aHR 1.38; 95% CI, 1.05-1.82; P = 0.02) and a trend towards all-cause mortality (aHR 1.28; 95% CI, 0.99-1.66; P = 0.07). Participants with diabetes had an increased risk of the composite renal outcome, the composite CV outcome, and all-cause mortality.

CONCLUSIONS

In individuals with CKD, prediabetes was not associated with composite renal outcome, but was associated with an increased risk of proteinuria progression and adverse CV outcomes.

Cell junction proteins: Crossing the glomerular filtration barrier in diabetic nephropathy

Diabetic nephropathy as a deleterious complication of diabetes mellitus and an important cause of end-stage renal failure is characterized by changes in the molecular and cellular levels. Cell-cell communication via the gap and tight junctions are involved in the pathogenesis of diseases such as diabetes and kidney failure. Studying cell junctions including gap junctions, tight junctions, and anchoring junctions within the nephron can be used as an early sign of diabetic nephropathy. Furthermore, cell junctions may be an upcoming target by pharmacological methods to improve treatments of diabetic nephropathy and pave the way to introduce promising therapeutic strategies based on cell-cell communications effects and its translation into clinical studies for the treatment of diabetic nephropathy.

NGAL and SMAD1 gene expression in the early detection of diabetic nephropathy by liquid biopsy

INTRODUCTION

Diabetic nephropathy (DN) is a disease that progresses with the slow and progressive decline of the glomerular filtration rate (GFR); the installation of this pathology is silent and one of the major causes of death in patients with diabetes.

AIMS

To identify new molecular biomarkers for early identification of the onset of DN in patients with type II diabetes mellitus (DM2). We studied the expression profile of the genes; suppressor of mothers against decapentaplegic type 1 (SMAD1), neutrophil gelatinase-associated lipocalin (NGAL) and type IV collagen (COLIV1A) in peripheral blood and urine sediment samples.

METHODS

Ninety volunteers, 51 with DM2 and 39 healthy, were recruited from the Faculdade de Medicina do ABC outpatient clinic. We conducted an interview and collected anthropometric data, as well as blood and urine samples for biochemical evaluation and real-time PCR amplification of the genes of interest.

RESULTS

Gene expression data: peripheral blood NGAL (DM2 0.09758±0.1914 vs CTL 0.02293±0.04578), SMAD1 (blood: DM2 0.01102±0.04059* vs CTL 0.0001317±0.0003609; urine: DM2 0.7195±2.344* vs CTL 0.09812±0.4755), there was no significant expression of COLIV1A. These genes demonstrated good sensitivity and specificity in the receiving operating characteristic curve evaluation.

CONCLUSION

Our data suggest the potential use of NGAL and SMAD1 gene expression in peripheral blood and urine samples as early biomarkers of DN.

The tubular hypothesis of nephron filtration and diabetic kidney disease

Kidney size and glomerular filtration rate (GFR) often increase with the onset of diabetes, and elevated GFR is a risk factor for the development of diabetic kidney disease. Hyperfiltration mainly occurs in response to signals passed from the tubule to the glomerulus: high levels of glucose in the glomerular filtrate drive increased reabsorption of glucose and sodium by the sodium-glucose cotransporters SGLT2 and SGLT1 in the proximal tubule. Passive reabsorption of chloride and water also increases. The overall capacity for proximal reabsorption is augmented by growth of the proximal tubule, which (alongside sodium-glucose cotransport) further limits urinary glucose loss. Hyperreabsorption of sodium and chloride induces tubuloglomerular feedback from the macula densa to increase GFR. In addition, sodium-glucose cotransport by SGLT1 on macula densa cells triggers the production of nitric oxide, which also contributes to glomerular hyperfiltration. Although hyperfiltration restores sodium and chloride excretion it imposes added physical stress on the filtration barrier and increases the oxygen demand to drive reabsorption. Tubular growth is associated with the development of a senescence-like molecular signature that sets the stage for inflammation and fibrosis. SGLT2 inhibitors attenuate the proximal reabsorption of sodium and glucose, normalize tubuloglomerular feedback signals and mitigate hyperfiltration. This tubule-centred model of diabetic kidney physiology predicts the salutary effect of SGLT2 inhibitors on hard renal outcomes, as shown in large-scale clinical trials.

The variability of glycated hemoglobin is associated with renal function decline in patients with type 2 diabetes

Background

The effect of glucose control, especially variability of glycated hemoglobin (HbA1c), on estimated glomerular filtration rate (eGFR) decline in type 2 diabetes is still debatable.

Methods

We used tertiles of coefficient of variation (CV) to determine the variability of HbA1c (HbA1c_CV). Mixed model repeated measures (MMRM) were used to evaluate the annual eGFR decline rate.

Results

In 1383 type 2 diabetic patients, we found the greater the HbA1c_CV, the greater the eGFR decline (p = 0.01, -0.99 in low, -1.73 in mid, and -2.53 ml/min/1.73 m²/year in high HbA1c_CV). Regardless of eGFR (⩾60 or <60 ml/min/1.73 m²), the same result holds (p = 0.019 and p = 0.007, respectively). In subgroup analysis of baseline HbA1c (%) (HbA1c < 7, 7 ⩽ HbA1c < 9, and HbA1c ⩾ 9), tertiles of HbA1c_CV showed similar effects on annual decline of eGFR (p = 0.193, 0.300, 0.182, respectively), although a trend for a steeper decline in renal function in the highest HbA1c_CV tertile was observed for all HbA1c strata, and even for HbA1c < 7%. A similar behavior was observed in patients with macroalbuminuria or normoalbuminuria (p = 0.219, and 0.109, respectively), with a significant trend in those with microalbuminuria (p = 0.019). Even in patients with HbA1c < 7, high HbA1c_CV also predicts rapid eGFR decline. Before macroalbuminuria, minimizing HbA1c_CV also has renal benefit.

Conclusions

HbA1c variability is an independent risk factor for deterioration of renal function. Even with well-controlled HbA1c levels (<7%), patients with high HbA1c_CV still experienced faster eGFR decline. Early minimization of glycemic variability (before macroalbuminuira) can curb deterioration of renal function. Monitoring and lowering of HbA1c_CV is highly recommended for diabetic care.

Determination of the glomerular filtration rate in patients with type 2 diabetes: An assessment of the agreement between 51Cr-EDTA plasma clearance and 99mTc-DTPA plasma clearance, 99mTc-DTPA renography and plasma creatinine prediction equation

AIMS

To investigate the agreement of glomerular filtration rate (GFR) determination between ⁵¹Cr-ethylenediaminetetraacetic acid (⁵¹Cr-EDTA) plasma clearance (GFR_EDTA) and ^99mTc-diethylenetriaminepentaacetic acid (^99mTc-DTPA) plasma clearance (GFR_DTPA), the Gates ^99mTc-DTPA renographic method (GFR_Gates) and the serum creatinine Chronic Kidney Disease Epidemiology Collaboration equation (CKD-EPI, GFR_SCr) in patients with type 2 diabetes mellitus (T2DM).

METHODS

Ninety-nine T2DM patients underwent GFR determinations simultaneously with ⁵¹Cr-EDTA and ^99mTc-DTPA (using the slope-intercept technique and the Brochner-Mortensen correction) and also with GFR_Gates and GFR_SCr.

RESULTS

In the comparison between GFR_EDTA versus GFR_DTPA, GFR_Gates and GFR_SCr, the Bland-Altman statistic provided 0.0 ± 13.2, 17.4* ± 28.8 and -5.9* ± 30.1 (*p < 0.001 for the difference from 0). Lin's concordance correlation coefficient showed substantial (0.976), poor (0.737) and poor (0.872) agreement, respectively. The proportion of the index results within the 30% and 10% of GFR_EDTA measurements were 95% and 74% for GFR_DTPA, 53% and 19% for GFR_Gates, and 83% and 26% for GFR_SCr, respectively.

CONCLUSION

In T2DM patients, a clinically acceptable agreement is demonstrated between ⁵¹Cr-EDTA and ^99mTc-DTPA plasma clearance for GFR measurements, suggesting conditional interchangeability between those compounds. Both the CKD-EPI prediction equation and the Gates' renographic method cannot assess GFR reliably, the latter appearing less unfailing than the former.

Sex Differences in Diabetic Kidney Disease

While the global prevalence of both type 1 and type 2 diabetes mellitus is similar in men and women, the consequences of diabetes on associated end-organ complications, including diabetic kidney disease appear to be more sex-specific. Particularly, women with diabetes have higher mortality rates for diabetes-related deaths, and higher prevalence of diabetic kidney disease risk factors such as hypertension, hyperglycemia, obesity, and dyslipidemia. However, the evidence for the impact of sex on diabetic kidney disease prevalence and disease progression is limited and inconsistent. Although most studies agree that the protective effect of the female sex against the development of kidney disease is diminished in the setting of diabetes, the reasons for this observation are unclear. Whether or not sex differences exist in the risk of diabetic kidney disease is also unclear, with studies reporting either higher risk in men, women, or no sex differences. Despite the remaining controversies, some of the factors that associate with sex differences in the risk of diabetic kidney disease are age at onset, and type and duration of diabetes. There is growing appreciation of the importance of sex hormones in the regulation of renal function, with estrogens generally considered to be renoprotective. Although some progress has been made towards better understanding of the mechanisms by which sex hormones play a role in the pathophysiology of diabetic kidney disease, the translational potential of this knowledge is still underappreciated. A better understanding of sex differences in diabetic kidney disease may provide basis for personalized and sex-specific treatment of diabetic kidney disease.

Association Between Living Kidney Donor Postdonation Hypertension and Recipient Graft Failure

BACKGROUND

Recipients of kidneys from living donors who subsequently develop end-stage renal disease (ESRD) also have higher graft failure, suggesting the 2 donor kidneys share risk factors that could inform recipient outcomes. Given that donor ESRD is rare, an earlier and more common postdonation outcome could serve as a surrogate to individualize counseling and management for recipients. Hypertension is a frequent event before donor ESRD; thus, early postdonation hypertension might indicate higher risk of graft failure.

METHODS

We studied Scientific Registry of Transplant Recipients data to quantify the association between early postdonation hypertension and recipient graft failure using propensity score-weighted Cox proportional hazards regression. We also examined the association between postdonation systolic blood pressure and graft failure.

RESULTS

Of 37 901 recipients, 2.4% had a donor who developed hypertension within 2 years postdonation. Controlling for donor and recipient characteristics, recipients whose donors developed hypertension had no higher risk for graft failure (adjusted hazard ratio [aHR] 1.03, 95% confidence interval [CI] 0.85-1.25, P = 0.72). This was consistent among subgroups of recipients at higher risk for adverse outcomes due to hyperfiltration: African American recipients (aHR 1.10, 95% CI 0.70-1.73, P = 0.68) and those with ESRD caused by hypertension (aHR 1.10, 95% CI 0.65-1.85, P = 0.73) or diabetes (aHR 0.80, 95% CI 0.56-1.13, P = 0.20). However, graft failure was associated with postdonation systolic blood pressure (per 10 mm Hg, aHR 1.05, 95% CI 1.03-1.08, P < 0.001).

CONCLUSIONS

Although postdonation systolic blood pressure is associated with graft failure, the reported diagnosis of hypertension as determined by the requirement for blood pressure treatment early postdonation did not portend a higher risk of recipient graft failure in the same way as eventual postdonation ESRD.

Perturbations in myocardial perfusion and oxygen balance in swine with multiple risk factors: a novel model of ischemia and no obstructive coronary artery disease

Comorbidities of ischemic heart disease, including diabetes mellitus (DM), hypercholesterolemia (HC) and chronic kidney disease (CKD), are associated with coronary microvascular dysfunction (CMD). Increasing evidence suggests that CMD may contribute to myocardial ‘Ischemia and No Obstructive Coronary Artery disease’ (INOCA). In the present study, we tested the hypothesis that CMD results in perturbations in myocardial perfusion and oxygen delivery using a novel swine model with multiple comorbidities. DM (streptozotocin), HC (high-fat diet) and CKD (renal embolization) were induced in 10 female swine (DM + HC + CKD), while 12 healthy female swine on a normal diet served as controls (Normal). After 5 months, at a time when coronary atherosclerosis was still negligible, myocardial perfusion, metabolism, and function were studied at rest and during treadmill exercise. DM + HC + CKD animals showed hyperglycemia, hypercholesterolemia, and impaired kidney function. During exercise, DM + HC + CKD swine demonstrated perturbations in myocardial blood flow and oxygen delivery, necessitating a higher myocardial oxygen extraction—achieved despite reduced capillary density—resulting in lower coronary venous oxygen levels. Moreover, myocardial efficiency was lower, requiring higher oxygen consumption for a given level of myocardial work. These perturbations in myocardial oxygen balance were associated with lower myocardial lactate consumption, stroke volume, and LVdP/dt_max, suggestive of myocardial ischemia and dysfunction. Further analyses showed a reduction in adenosine-recruitable coronary flow reserve, but this was exclusively the result of an increase in basal coronary blood flow, while maximal coronary flow per gram of myocardium was maintained; the latter was consistent with the unchanged arteriolar wall/lumen ratio, arteriolar density and peri-arteriolar collagen content. However, isolated small arteries displayed selective blunting of endothelium-dependent vasodilation in response to bradykinin in DM + HC + CKD swine, suggesting that changes in coronary microvascular function rather than in structure contributed to the perturbations in myocardial oxygen delivery. In conclusion, common comorbidities in swine result in CMD, in the absence of appreciable atherosclerosis, which is severe enough to produce perturbations in myocardial oxygen balance, particularly during exercise, resembling key features of INOCA.

Estimated Glomerular Filtration Rates Calculated by New and Old Equations in Children and Adolescents With Type 1 Diabetes-What to Do With the Results?

Background: To apply and evaluate various equations for estimated glomerular filtration rates (eGFR) in a large paediatric type 1 diabetes population and compare the eGFR values with urinary creatinine clearances (UCC) in a subset of patients. Methods: Six eGFR formulae applicable for children and adolescents were used for calculation of eGFR values in 36,782 children/adolescents with type 1 diabetes. Via regression models, factors influencing eGFR values were identified. eGFR values were compared with measured UCC in 549 patients. Spearman correlation coefficients were given to assess the relation of eGFR and UCC values. Bland-Altman-Plots with corresponding linear regression were drawn to evaluate the agreement between eGFR and UCC. Results: eGFR values differed widely depending on the formula used, resulting in a percentage of pathological values <60 mL/min/1.73 m2 up to 8%. Regression models showed age, sex, and duration of diabetes as influencing factors. Microalbuminuria was associated with significantly higher eGFR values for all formulae. In comparison of eGFR with UCC, the highest correlation coefficient was 0.33, the lowest 0.01. Bland-Altman-Plots demonstrated graphically a poor agreement between eGFR and UCC, regardless of the formula used. Conclusions: The broad range of eGFR values indicate that an ideal eGFR formula for children and adolescence with T1D is yet missing. The minimal agreement between measured UCC and eGFR values urges us to be careful in application and interpretation of eGFR values regardless of the formula used.

The primary cilia in diabetic kidney disease: A tubulocentric view?

Diabetic kidney disease is growing exponentially. This review aims to discuss alternate therapeutic approaches beyond the glomerulocentric view and to consider a novel tubulocentric approach with focus on the primary cilia. Renin-angiotensin-aldosterone system blockade to decrease glomerular capillary pressure and prevent albuminuria has been the mainstay of treatment for diabetic and non-diabetic proteinuric kidney disease. Landmark clinical trials have also shown cardiorenal benefit with sodium-glucose linked co-transporter 2 inhibitors and glucagon-like peptide 1 receptor analogues in patients with type 2 diabetes. Effective renoprotective drugs seem to have a common mechanistic mode of reducing glomerular hyperfiltration/hypertension. In the tubules, primary cilia act as "antennae" to detect mechanosensory changes such as glomerular hyperfiltration and trgger intracellular signalling pathways. They are also implicated in obesity and metabolic disorders linked to diabetes. To conclude, primary cilia of the kidney tubules offer a novel therapeutic target and may complement the current glomerulocentric approaches.

Obesity, kidney dysfunction and hypertension: mechanistic links

Excessive adiposity raises blood pressure and accounts for 65-75% of primary hypertension, which is a major driver of cardiovascular and kidney diseases. In obesity, abnormal kidney function and associated increases in tubular sodium reabsorption initiate hypertension, which is often mild before the development of target organ injury. Factors that contribute to increased sodium reabsorption in obesity include kidney compression by visceral, perirenal and renal sinus fat; increased renal sympathetic nerve activity (RSNA); increased levels of anti-natriuretic hormones, such as angiotensin II and aldosterone; and adipokines, particularly leptin. The renal and neurohormonal pathways of obesity and hypertension are intertwined. For example, leptin increases RSNA by stimulating the central nervous system proopiomelanocortin-melanocortin 4 receptor pathway, and kidney compression and RSNA contribute to renin-angiotensin-aldosterone system activation. Glucocorticoids and/or oxidative stress may also contribute to mineralocorticoid receptor activation in obesity. Prolonged obesity and progressive renal injury often lead to the development of treatment-resistant hypertension. Patient management therefore often requires multiple antihypertensive drugs and concurrent treatment of dyslipidaemia, insulin resistance, diabetes and inflammation. If more effective strategies for the prevention and control of obesity are not developed, cardiorenal, metabolic and other obesity-associated diseases could overwhelm health-care systems in the future.

Five-year kidney outcomes of bariatric surgery differ in severely obese adolescents and adults with and without type 2 diabetes

Bariatric surgery improves markers of kidney health in severe obesity, yet it is unclear if kidney disease outcomes differ according to age at surgery. Therefore, we examined health effects of Roux-en-Y gastric bypass between 161 adolescents and 396 adults participating in two related but distinct studies. Primary outcomes were elevated urine albumin-to-creatinine ratio (UACR) of 30 mg/g or more and hyperfiltration (an estimated glomerular filtration rate of 135 ml/min/1.73m² or more). Analyses were stratified by the presence of pre-operative type 2 diabetes. Adolescents with pre-operative type 2 diabetes had a significantly increased prevalence of elevated UACR prior to surgery compared to adults (22.5 vs. 9.0%). Resolution of elevated UACR following surgery differed between adolescents and adults with type 2 diabetes, with adolescents experiencing a significantly earlier improvement following surgery. Adolescents without pre-operative type 2 diabetes demonstrated a significantly increased prevalence of UACR prior to surgery compared to adults (9.4 vs. 4.5%), with no improvement occurring in either group post-operatively. Adolescents with pre-operative type 2 diabetes had a significantly increased prevalence of hyperfiltration that remained throughout the study period, whereas hyperfiltration prevalence was similar among those without type 2 diabetes. Thus, adolescents with pre-operative type 2 diabetes experienced earlier attenuation of elevated UACR compared to adults with pre-operative type 2 diabetes in response to gastric bypass.

Mechanisms of Synergistic Interactions of Diabetes and Hypertension in Chronic Kidney Disease: Role of Mitochondrial Dysfunction and ER Stress

PURPOSE OF REVIEW

To discuss the importance of synergistic interactions of diabetes mellitus (DM) and hypertension (HT) in causing chronic kidney disease and the potential molecular mechanisms involved.

RECENT FINDINGS

DM and HT are the two most important risk factors for chronic kidney disease (CKD) and development of end-stage renal disease (ESRD). The combination of HT and DM may synergistically promote the progression of renal injury through mechanisms that have not been fully elucidated. Hyperglycemia and other metabolic changes in DM initiate endoplasmic reticulum (ER) stress and mitochondrial (MT) adaptation in different types of glomerular cells. These adaptations appear to make the cells more vulnerable to HT-induced mechanical stress. Excessive activation of mechanosensors, possibly via transient receptor potential cation channel subfamily C member 6 (TRPC6), may lead to impaired calcium (Ca²⁺) homeostasis and further exacerbate ER stress and MT dysfunction promoting cellular apoptosis and glomerular injury. The synergistic effects of HT and DM to promote kidney injury may be mediated by increased intraglomerular pressure. Chronic activation of mechanotransduction signaling may amplify metabolic effects of DM causing cellular injury through a vicious cycle of impaired Ca²⁺ homeostasis, mitochondrial dysfunction, and ER stress.

Diabetic kidney disease: new clinical and therapeutic issues. Joint position statement of the Italian Diabetes Society and the Italian Society of Nephrology on "The natural history of diabetic kidney disease and treatment of hyperglycemia in patients with type 2 diabetes and impaired renal function"

AIMS

This joint document of the Italian Diabetes Society and the Italian Society of Nephrology reviews the natural history of diabetic kidney disease (DKD) in the light of the recent epidemiological literature and provides updated recommendations on anti-hyperglycemic treatment with non-insulin agents.

DATA SYNTHESIS

Recent epidemiological studies have disclosed a wide heterogeneity of DKD. In addition to the classical albuminuric phenotype, two new albuminuria-independent phenotypes have emerged, i.e., "nonalbuminuric renal impairment" and "progressive renal decline", suggesting that DKD progression toward end-stage kidney disease (ESKD) may occur through two distinct pathways, albuminuric and nonalbuminuric. Several biomarkers have been associated with decline of estimated glomerular filtration rate (eGFR) independent of albuminuria and other clinical variables, thus possibly improving ESKD prediction. However, the pathogenesis and anatomical correlates of these phenotypes are still unclear. Also the management of hyperglycemia in patients with type 2 diabetes and impaired renal function has profoundly changed during the last two decades. New anti-hyperglycemic drugs, which do not cause hypoglycemia and weight gain and, in some cases, seem to provide cardiorenal protection, have become available for treatment of these individuals. In addition, the lowest eGFR safety thresholds for some of the old agents, particularly metformin and insulin secretagogues, have been reconsidered.

CONCLUSIONS

The heterogeneity in the clinical presentation and course of DKD has important implications for the diagnosis, prognosis, and possibly treatment of this complication. The therapeutic options for patients with type 2 diabetes and impaired renal function have substantially increased, thus allowing a better management of these individuals.

Kidney Function Decline among Black Patients with Sickle Cell Trait and Sickle Cell Disease: An Observational Cohort Study

BACKGROUND

Sickle cell trait and sickle cell disease are thought to be independent risk factors for CKD, but the trajectory and predictors of kidney function decline in patients with these phenotypes are not well understood.

METHODS

Our multicenter, observational study used registry data (collected January 2005 through June 2018) and included adult black patients with sickle cell trait or disease (exposures) or normal hemoglobin phenotype (reference) status (ascertained by electrophoresis) and at least 1 year of follow-up and three eGFR values. We used linear mixed models to evaluate the difference in the mean change in eGFR per year.

RESULTS

We identified 1251 patients with sickle cell trait, 230 with sickle cell disease, and 8729 reference patients, with a median follow-up of 8 years. After adjustment, eGFR declined significantly faster in patients with sickle cell trait or sickle cell disease compared with reference patients; it also declined significantly faster in patients with sickle cell disease than in patients with sickle cell trait. Male sex, diabetes mellitus, and baseline eGFR ≥90 ml/min per 1.73 m2 were associated with faster eGFR decline for both phenotypes. In sickle cell trait, low hemoglobin S and elevated hemoglobin A were associated with faster eGFR decline, but elevated hemoglobins F and A2 were renoprotective.

CONCLUSIONS

Sickle cell trait and disease are associated with faster eGFR decline in black patients, with faster decline in sickle cell disease. Low hemoglobin S was associated with faster eGFR decline in sickle cell trait but may be confounded by concurrent hemoglobinopathies. Prospective and mechanistic studies are needed to develop best practices to attenuate eGFR decline in such patients.

Time-averaged serum uric acid and 10-year incident diabetic kidney disease: A prospective study from China

BACKGROUND

The association between serum uric acid (SUA) and the risk of diabetic kidney diseases (DKD) remains controversial. We aim to investigate the association between time-averaged SUA and long-term incident DKD among general population-based patients with diabetes.

METHODS

Altogether 1327 patients with diabetes and without kidney disease (estimated glomerular filtration rate [eGFR] ≥ 60 mL/min/1.73m² , and without proteinuria) were included. Incident DKD were defined by the occurrence of renal function decline (eGFR<60 mL/min/1.73m² ) and/or macroalbuminuria (urinary albumin-creatinine-ratio ≥ 30 mg/mM creatinine). The associations between baseline and time-averaged SUA and DKD were analyzed.

RESULTS

The mean age was 53.7 ± 8.0. During 10.2 ± 0.4 years' follow-up, 85 (6.4%) patients developed renal function decline and 101 (7.6%) patients developed macroalbuminuria. Compared to those with time-averaged SUA in the second quartile (207-240 μM/L for women, 233-272 μM/L for men), odds ratio (OR) for renal function decline was 1.92 (95% confidence interval [CI], 1.02 to 3.62; P = .04) among those with SUA in the top quartile (women≥285 μM/L; men≥324 μM/L); and OR for macroalbuminuria was 1.86 (95% CI 1.01 to 3.43; P = .05) among those with SUA in the bottom quartile (women ≤207 μM/L; men ≤233 μM/L)). No significant associations were observed between baseline SUA with incident DKD.

CONCLUSIONS

Long-term exposure to both high and low SUA level are associated with increased risk of incident DKD among patients with diabetes.

SGLT-2 inhibitors in diabetes: a focus on renoprotection

Type 2 diabetes mellitus is an important public health problem, with a significant impact on cardiovascular morbidity and mortality and an important risk factor for chronic kidney disease. Various hypoglycemic therapies have proved to be beneficial to clinical outcomes, while others have failed to provide an improvement in cardiovascular and renal failure, only reducing blood glucose levels. Recently, sodium-glucose cotransporter-2 (SGLT2) inhibitors, represented by the empagliflozin, dapagliflozin, and canagliflozin, have been showing satisfactory and strong results in several clinical trials, especially regarding the reduction of cardiovascular mortality, reduction of hospitalization due to heart failure, reduction of albuminuria, and long-term maintenance of the glomerular filtration rate. The benefit from SGLT2 inhibitors stems from its main mechanism of action, which occurs in the proximal tubule of the nephron, causing glycosuria, and a consequent increase in natriuresis. This leads to increased sodium intake by the juxtaglomerular apparatus, activating the tubule glomerular-feedback and, finally, reducing intraglomerular hypertension, a frequent physiopathological condition in kidney disease caused by diabetes. In addition, this class of medication presents an appropriate safety profile, and its most frequently reported complication is an increase in the incidence of genital infections. Thus, these hypoglycemic agents gained space in practical recommendations for the management of type 2 diabetes mellitus and should be part of the initial therapeutic approach to provide, in addition to glycemic control, cardiovascular outcomes, and the renoprotection in the long term.

Keap1/Nrf2/ARE signaling unfolds therapeutic targets for redox imbalanced-mediated diseases and diabetic nephropathy

Hyperglycemia/oxidative stress has been implicated in the initiation and progression of diabetic complications while the components of Keap1/Nrf2/ARE signaling are being exploited as therapeutic targets for the treatment/management of these pathologies. Antioxidant agents like drugs, nutraceuticals and pure compounds that target the proteins of this pathway and their downstream genes hold the therapeutic strength to put the progression of this disease at bay. Here, we elucidate how the modulation of Keap1/Nrf2/ARE had been exploited for the treatment/management of end-stage diabetic kidney complication (diabetic nephropathy) by looking into (1) Nrf2 nuclear translocation and phosphorylation by some protein kinases at specific amino acid sequences and (2) Keap1 downregulation/Keap1-Nrf2 protein-protein inhibition (PPI) as potential therapeutic mechanisms exploited by Nrf2 activators for the modulation of diabetic nephropathy biomarkers (Collagen IV, Laminin, TGF-β1 and Fibronectin) that ultimately lead to the amelioration of this disease progression. Furthermore, we brought to limelight the relationship between diabetic nephropathy and Keap1/Nrf2/ARE and finally elucidate how the modulation of this signaling pathway could be further explored to create novel therapeutic milestones.

Empagliflozin Protects Against Proximal Renal Tubular Cell Injury Induced by High Glucose via Regulation of Hypoxia-Inducible Factor 1-Alpha

BACKGROUND

Evidence from both animal and human studies clearly supports the renal beneficial effects of empagliflozin (emp), a sodium glucose co-transporter 2 (SGLT2) inhibitor, but the mechanism in which it exerts its effect is not well understood. In this study, we investigated the capability of emp on reducing hyperglycemia-induced renal proximal tubular epithelial cells injury and we evaluated if the renoprotective effect of emp associates with hypoxia-inducible factor-1α (HIF-1α).

MATERIALS AND METHODS

Human kidney cell lines (HK-2 cells) were incubated in normoxia, high glucose with or without emp treatment for 72 hours to evaluate the induction of HIF-1α, glucose transporter-1, SGLT2, the fibrosis signal pathway and epithelial-mesenchymal transition (EMT) markers.

RESULTS

High glucose (HG) increased expression of Collagen IV, Fibronectin, transforming growth factor-beta1 (TGF-β1). However, emp treatment remarkably decreased expression of TGF-β1, accumulation of extracellular matrix proteins (Fibronectin, Collagen IV), as well as (phosphorylated-smad3) P-smad3. HG increased SGLT2 protein expression compared to normal glucose (NG) while emp significantly decreased SGLT2 expression. Furthermore, emp decreased high glucose-induced alpha-smooth muscle actin (α-SMA) expression and reversed epithelial marker (E-catherin) suppression induced by high glucose. In addition, emp treatment for 72 h increased expression of HIF-1α protein (95% CI: -0.5918 to -0.002338, at 100nM, P < 0.05, 95% CI -0.6631 to -0.07367 at 500nM, P < 0.05) in hyperglycemic normoxic HK-2 cells. Furthermore, we observed increased expression of GLUT-1 protein after emp treatment and remarkably decreased cell proliferation.

CONCLUSION

Emp treatment protected proximal renal tubular cells injury induced by high glucose. Induction of HIF-1α expression by emp may play an essential role in the protection of high glucose-induced proximal renal tubular epithelial cells injury.

Augmented renal clearance in pediatric intensive care: are we undertreating our sickest patients?

Many critically ill patients display a supraphysiological renal function with enhanced renal perfusion and glomerular hyperfiltration. This phenomenon described as augmented renal clearance (ARC) may result in enhanced drug elimination through renal excretion mechanisms. Augmented renal clearance seems to be triggered by systemic inflammation and therapeutic interventions in intensive care. There is growing evidence that ARC is not restricted to the adult intensive care population, but is also prevalent in critically ill children. Augmented renal clearance is often overlooked due to the lack of reliable methods to assess renal function in critically ill children. Standard equations to calculate glomerular filtration rate (GFR) are developed for patients who have a steady-state creatinine production and a stable renal function. Those formulas are not reliable in critically ill patients with acutely changing GFR and tend to underestimate true GFR in patients with ARC. Tools for real-time, continuous, and non-invasive measurement of fluctuating GFR are most needed to identify changes in kidney function during critical illness and therapeutic interventions. Such devices are currently being validated and hold a strong potential to become the standard of practice. In the meantime, urinary creatinine clearance is considered the most reliable method to detect ARC in critically ill patients. Augmented renal clearance is clearly associated with subtherapeutic antimicrobial concentrations and subsequent therapeutic failure. This warrants the need for adjusted dosing regimens to optimize pharmacokinetic and pharmacodynamic target attainment. This review aims to summarize current knowledge on ARC in critically ill children, to give insight into its possible pathophysiological mechanism, to evaluate screening methods for ARC in the pediatric intensive care population, and to illustrate the effect of ARC on drug exposure, therapeutic efficacy, and clinical outcome.

Effect of Surgical Versus Medical Therapy on Diabetic Kidney Disease Over 5 Years in Severely Obese Adolescents With Type 2 Diabetes

OBJECTIVE

To compare diabetic kidney disease (DKD) rates over 5 years of follow-up in two cohorts of severely obese adolescents with type 2 diabetes (T2D) undergoing medical or surgical treatment for T2D.

RESEARCH DESIGN AND METHODS

A secondary analysis was performed of data collected from obese participants of similar age and racial distribution enrolled in the Teen-Longitudinal Assessment of Bariatric Surgery (Teen-LABS) and the Treatment Options of Type 2 Diabetes in Adolescents and Youth (TODAY) studies. Teen-LABS participants underwent metabolic bariatric surgery (MBS). TODAY participants were randomized to metformin alone or in combination with rosiglitazone or intensive lifestyle intervention, with insulin therapy given for glycemic progression. Glycemic control, BMI, estimated glomerular filtration rate (eGFR), urinary albumin excretion (UAE), and prevalence of hyperfiltration (eGFR ≥135 mL/min/1.73 m²) and elevated UAE (≥30 mg/g) were assessed annually.

RESULTS

Participants with T2D from Teen-LABS (n = 30, mean ± SD age, 16.9 ± 1.3 years; 70% female; 60% white; BMI 54.4 ± 9.5 kg/m²) and TODAY (n = 63, age 15.3 ± 1.3 years; 56% female; 71% white; BMI 40.5 ± 4.9 kg/m²) were compared. During 5 years of follow-up, hyperfiltration decreased from 21% to 18% in Teen-LABS and increased from 7% to 48% in TODAY. Elevated UAE decreased from 27% to 5% in Teen-LABS and increased from 21% to 43% in TODAY. Adjusting for baseline age, sex, BMI, and HbA_1c, TODAY participants had a greater odds of hyperfiltration (odds ratio 15.7 [95% CI 2.6, 94.3]) and elevated UAE (27.3 [4.9, 149.9]) at 5 years of follow-up.

CONCLUSIONS

Compared with MBS, medical treatment of obese youth with T2D was associated with a higher odds of DKD over 5 years.

Klotho deficiency aggravates diabetes-induced podocyte injury due to DNA damage caused by mitochondrial dysfunction

Diabetic nephropathy (DN) is a progressive disease, the main pathogeny of which is podocyte injury inducing glomerular filtration barrier and proteinuria. The occurrence and development of DN could be partly attributed to the reactive oxygen species (ROS) generated by mitochondria. However, research on how mitochondrial dysfunction (MtD) ultimately causes DNA damage is poor. Here, we investigated the influence of Klotho deficiency on high glucose (HG)-induced DNA damage in vivo and in vitro. First, we found that the absence of Klotho aggravated diabetic phenotypes indicated by podocyte injury accompanied by elevated urea albumin creatinine ratio (UACR), creatinine and urea nitrogen. Then, we further confirmed that Klotho deficiency could significantly aggravate DNA damage by increasing 8-OHdG and reducing OGG1. Finally, we demonstrated Klotho deficiency may promote MtD to promote 8-OHdG-induced podocyte injury. Therefore, we came to a conclusion that Klotho deficiency may promote diabetes-induced podocytic MtD and aggravate 8-OHdG-induced DNA damage by affecting OOG1.