Canagliflozin could improve the levels of renal oxygenation in newly diagnosed type 2 diabetes patients with normal renal function

Sodium-dependent glucose transporter 2 inhibitor alleviates renal lipid deposition and improves renal oxygenation levels in newly diagnosed type 2 diabetes mellitus patients: a randomized controlled trial

BACKGROUND

Sodium-dependent glucose transporter 2 inhibitor (SGLT2i) has the advantages of effectively lowering blood glucose levels and improving renal outcomes in diabetic patients. This study evaluated the effect of canagliflozin on intrarenal lipid content and oxygenation in newly diagnosed type 2 diabetes mellitus (T2DM) patients.

METHODS

A total of 64 newly diagnosed T2DM patients with normal renal function were randomly divided into canagliflozin (n = 33) and glimepiride control (n = 31) groups. All patients underwent functional magnetic resonance imaging (fMRI) scanning to assay patients' intrarenal lipid content and oxygenation level before and after 24 weeks of treatment. Furthermore, the relationship between body mass index and intrarenal lipid content in T2DM patients was analyzed and the correlation between changes in intrarenal lipid content and improvements in renal hypoxia was further assessed.

RESULTS

The canagliflozin group had a greater decrease in body weight and blood uric acid level than the glimepiride group (all P < 0.05). The intrarenal lipid content could be significantly reduced after canagliflozin treatment for 24 weeks. The R2* values, a parameter for quantifying the oxygen content in tissues and is inversely related to the oxygen content, of the renal cortex and medulla in the canagliflozin group decreased from the baseline by 6.40% (P < 0.01) and 12.09% (P = 0.000007), respectively. In addition, the degree of reduction of fat fraction (ΔFF) in the kidneys of the canagliflozin group was correlated with the degree of improvement of oxygenation level (ΔR2*) in the renal cortex (r = 0.422, P = 0.014).

CONCLUSIONS

The early renal protective effect of SGLT2i in newly diagnosed T2DM patients may be partly attributed to the amelioration of renal hypoxia via the alleviation of ectopic lipid deposition in the kidneys.

TRIAL REGISTRATION

Chu Hsien-I Memorial Hospital of Tianjin Medical University (ChiCTR2000037951).

Magnetic Resonance Imaging in Clinical Trials of Diabetic Kidney Disease

Chronic kidney disease (CKD) associated with diabetes mellitus (DM) (known as diabetic kidney disease, DKD) is a serious and growing healthcare problem worldwide. In DM patients, DKD is generally diagnosed based on the presence of albuminuria and a reduced glomerular filtration rate. Diagnosis rarely includes an invasive kidney biopsy, although DKD has some characteristic histological features, and kidney fibrosis and nephron loss cause disease progression that eventually ends in kidney failure. Alternative sensitive and reliable non-invasive biomarkers are needed for DKD (and CKD in general) to improve timely diagnosis and aid disease monitoring without the need for a kidney biopsy. Such biomarkers may also serve as endpoints in clinical trials of new treatments. Non-invasive magnetic resonance imaging (MRI), particularly multiparametric MRI, may achieve these goals. In this article, we review emerging data on MRI techniques and their scientific, clinical, and economic value in DKD/CKD for diagnosis, assessment of disease pathogenesis and progression, and as potential biomarkers for clinical trial use that may also increase our understanding of the efficacy and mode(s) of action of potential DKD therapeutic interventions. We also consider how multi-site MRI studies are conducted and the challenges that should be addressed to increase wider application of MRI in DKD.

Separate and combined effects of semaglutide and empagliflozin on kidney oxygenation and perfusion in people with type 2 diabetes: a randomised trial

AIMS/HYPOTHESIS

Glucagon-like peptide-1 receptor agonists (GLP-1ras) and sodium-glucose cotransporter 2 inhibitors (SGLT2is) have shown kidney-protective effects. Improved kidney oxygenation and haemodynamic changes are suggested mechanisms; however, human data are scarce. We therefore investigated whether semaglutide (GLP-1ra), empagliflozin (SGLT2i) or their combination improve kidney oxygenation and perfusion.

METHODS

The trial was undertaken at Aarhus University Hospital, Denmark. A total of 120 people with type 2 diabetes (HbA1c ≥48 mmol/mol [6.5%]) and at high risk of CVD (age ≥50 years) were randomised into four parallel groups (n=30 in each group) for 32 weeks: 1.0 mg semaglutide (open label); 10 mg empagliflozin (blinded to participants, caregivers, examiners and outcome assessors); their combination (1.0 mg semaglutide open label plus 10 mg empagliflozin blinded to participants, caregivers, examiners and outcome assessors); and placebo tablet (blinded to participants, caregivers, examiners and outcome assessors). Sequentially numbered, sealed envelopes containing computer-generated randomisation codes, provided by Glostrup Pharmacy, Glostrup, Denmark, determined the intervention. The two co-primary outcomes were change in kidney oxygenation and change in arterial stiffness. This paper reports on kidney oxygenation, for which 80 individuals as prespecified, 20 in each group, underwent MRI. We primarily hypothesised that kidney oxygenation would be improved in the active treatment groups compared with placebo after 32 weeks. Secondary outcomes included changes in kidney perfusion, erythropoietin, haematocrit, urine albumin/creatinine ratio (UACR) and GFR (measured using technetium-99m) compared with baseline and between treatment groups at week 32.

RESULTS

Our model estimated a common baseline R2* value across all four groups in the cortex and the medulla. At baseline, the value was 24.5 (95% CI 23.9, 24.9) Hz in the medulla. After 32 weeks, the R2* values in the medulla were estimated to be 25.4 (95% CI 24.7, 26.2) Hz in the empagliflozin group and 24.5 (95% CI 23.9, 25.1) Hz in the placebo group (p=0.016) (higher R2* corresponds to a lower oxygenation). Semaglutide decreased perfusion in both the cortex and the medulla. Empagliflozin increased erythropoietin and haematocrit. All three active treatments decreased GFR but not UACR. Ten serious adverse events were reported, among them two occurrences of semaglutide-associated obstipation.

CONCLUSIONS/INTERPRETATION

Our hypothesis, that semaglutide, empagliflozin or their combination improve kidney oxygenation, was rejected. On the contrary, empagliflozin induced a reduction in medullary kidney oxygenation. Semaglutide substantially reduced kidney perfusion without affecting oxygenation.

TRIAL REGISTRATION

Clinicaltrialsregister.eu EudraCT 2019-000781-38 FUNDING: Novo Nordisk Foundation, Central Denmark Region Research Fund and Danish Medical Associations Research Foundation.

Type 2 Diabetes (T2DM) and Parkinson's Disease (PD): a Mechanistic Approach

Growing evidence suggest that there is a connection between Parkinson's disease (PD) and insulin dysregulation in the brain, whilst the connection between PD and type 2 diabetes mellitus (T2DM) is still up for debate. Insulin is widely recognised to play a crucial role in neuronal survival and brain function; any changes in insulin metabolism and signalling in the central nervous system (CNS) can lead to the development of various brain disorders. There is accumulating evidence linking T2DM to PD and other neurodegenerative diseases. In fact, they have a lot in common patho-physiologically, including insulin dysregulation, oxidative stress resulting in mitochondrial dysfunction, microglial activation, and inflammation. As a result, initial research should focus on the role of insulin and its molecular mechanism in order to develop therapeutic outcomes. In this current review, we will look into the link between T2DM and PD, the function of insulin in the brain, and studies related to impact of insulin in causing T2DM and PD. Further, we have also highlighted the role of various insulin signalling pathway in both T2DM and PD. We have also suggested that T2DM-targeting pharmacological strategies as potential therapeutic approach for individuals with cognitive impairment, and we have demonstrated the effectiveness of T2DM-prescribed drugs through current PD treatment trials. In conclusion, this investigation would fill a research gap in T2DM-associated Parkinson's disease (PD) with a potential therapy option.

Lower Blood Oxygen Saturation is Associated With Microvascular Complications in Individuals With Type 1 Diabetes

CONTEXT

Blood oxygen saturation (SpO2) is lower in type 1 diabetes (T1D) compared with nondiabetic controls. Hypoxia (low tissue oxygenation) is thought to be a risk factor for progression of diabetic complications, but it is unknown whether hypoxemia (low SpO2) is associated with diabetic complications.

OBJECTIVE

To test if hypoxemia is associated with presence of diabetic complications in T1D.

DESIGN, SETTING, AND METHODS

Cross-sectional study in persons with T1D divided by a previously suggested threshold in low (<96%) and high (≥96%) SpO2, measured in the supine position with pulse oximetry. Complications included albuminuria (2 of 3 consecutive measurements ≥30 mg/g), any diabetic retinopathy, neuropathy, and history of cardiovascular disease (CVD). Odds ratios were adjusted for age, diabetes duration, sex, smoking, physical activity, body mass index, systolic blood pressure, and blood hemoglobin.

RESULTS

We included 659 persons, 23 (3.5%) with low and 636 (96.5%) with high SpO2. In total, 151 (23%) had albuminuria, 233 (36%) had retinopathy, 231 (35%) had neuropathy, and 72 (11%) had CVD. The adjusted odds ratio (95% CI, P value) for low vs high SpO2 was 3.4 (1.3-8.7, P = 0.01) for albuminuria, 2.8 (1.0-7.5, P = 0.04) for retinopathy, 5.8 (1.8-18.6, P < 0.01) for neuropathy, and nonsignificant for CVD (0.6 [0.2-2.4, P = 0.51]).

CONCLUSIONS

SpO2 below 96% was associated with increased presence of albuminuria, retinopathy, and neuropathy in T1D, but not with CVD. Whether hypoxemia could be a target of intervention to prevent progression in microvascular disease in type 1 diabetes should be investigated.

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.

Correlation between Blood Oxygen Level-Dependent Magnetic Resonance Imaging Images and Prognosis of Patients with Multicenter Diabetic Nephropathy on account of Artificial Intelligence Segmentation Algorithm

This study was aimed to analyze the correlation between blood oxygen level-dependent magnetic resonance imaging (BOLD-MRI) images and prognosis of patients with diabetic nephropathy (DN) based on artificial intelligence (AI) segmentation algorithm, so as to provide references for diagnosis and treatment as well as prognosis analysis of patients DN. In this study, a kernel function-based fuzzy C-means algorithm (KFCM) model was proposed, and the FCM algorithm based on neighborhood pixel information (BCFCM) and the FCM algorithm based on efficiency improvement (EnFCM) were introduced for comparison to analyze the image segmentation effects of three algorithms. The results showed that the partition coefficient (V_pc) and partition entropy (V_pe) of the KFCM algorithm were 0.801 and 0.602, respectively, which were better than those of the traditional FCM, BCFCM, and EnFCM algorithm. At the same time, the effects of correlation between renal cortex R2∗ (RC-R2∗), renal medulla R2∗ (RM-R2∗), renal cortex D (RC-D), renal medulla D (RM-D) and renal function on the prognosis were compared. The results showed that the correlation coefficients between RC-R2∗, RM-R2∗, RC-D, RM-D and renal function were 0.57, 0.62, 0.49, and 0.38, respectively; among them, RC-R2∗ and RM-R2∗ were negatively correlated to the estimated glomerular filtration rate (eGFR), and the difference between the groups was statistically significant (P <0.05). Among the factors affecting the prognosis of DN patients, the GFR, hemoglobin (Hb), RC-R2∗, RM-R2∗, and RC-D were all related to the prognosis of DN, and the difference between groups was statistically obvious (P <0.05). It suggested that the KFCM algorithm proposed in this study showed the relatively best segmentation effect on BOLD-MRI images for DN patients; an increase in R2∗ indicated a poor prognosis, and an increase in the RC-D value indicated a better prognosis.

Current Use and Complementary Value of Combining in Vivo Imaging Modalities to Understand the Renoprotective Effects of Sodium-Glucose Cotransporter-2 Inhibitors at a Tissue Level

Sodium-glucose cotransporter-2 inhibitors (SGLT2i) were initially developed to treat diabetes and have been shown to improve renal and cardiovascular outcomes in patients with- but also without diabetes. The mechanisms underlying these beneficial effects are incompletely understood, as is the response variability between- and within patients. Imaging modalities allow in vivo quantitative assessment of physiological, pathophysiological, and pharmacological processes at kidney tissue level and are therefore increasingly being used in nephrology. They provide unique insights into the renoprotective effects of SGLT2i and the variability in response and may thus contribute to improved treatment of the individual patient. In this mini-review, we highlight current work and opportunities of renal imaging modalities to assess renal oxygenation and hypoxia, fibrosis as well as interaction between SGLT2i and their transporters. Although every modality allows quantitative assessment of particular parameters of interest, we conclude that especially the complementary value of combining imaging modalities in a single clinical trial aids in an integrated understanding of the pharmacology of SGLT2i and their response variability.

Understanding the protective effects of SGLT2 inhibitors in type 2 diabetes patients with chronic kidney disease

INTRODUCTION

Sodium-glucose co-transporter type 2 inhibitors (SGLT2is) were developed as glucose-lowering agents for the management of type 2 diabetes (T2D). Unexpectedly, they showed a significant reduction in hospitalization for heart failure and hard renal outcomes in patients with and without T2D. Underlying mechanisms remain a matter of debate.

AREAS COVERED

We summarize the protective renal effects of SGLT2is in patients with cardiovascular disease, chronic kidney disease (CKD, especially with albuminuria) or heart failure; a description of the safety of SGLT2is, with a special focus on the risk/benefit balance in people with stage 3 CKD; a comprehensive discussion of mechanisms that could explain nephro-protection; a reappraisal of the positioning of SGLT2is in recent international guidelines.

EXPERT OPINION

Several mechanisms could contribute to improved renal prognosis with SGLT2is, among which a reduction in intraglomerular pressure by restoring the tubuloglomerular feedback, a diuretic effect that contributes to lower albuminuria and renal decongestion, especially if fluid overload is present, a reduction in renal oxygen consumption, an improvement of heart failure status with less cardiorenal syndrome and a lower risk of acute renal injury. All these effects may be mutually not exclusive, and their respective contribution may differ according to patient characteristics.