Renal endothelial dysfunction in diabetic nephropathy

Endothelial dysfunction and cardiovascular diseases: The role of human induced pluripotent stem cells and tissue engineering

Cardiovascular disease (CVD) remains to be the leading cause of death globally today and therefore the need for the development of novel therapies has become increasingly important in the cardiovascular field. The mechanism(s) behind the pathophysiology of CVD have been laboriously investigated in both stem cell and bioengineering laboratories. Scientific breakthroughs have paved the way to better mimic cell types of interest in recent years, with the ability to generate any cell type from reprogrammed human pluripotent stem cells. Mimicking the native extracellular matrix using both organic and inorganic biomaterials has allowed full organs to be recapitulated in vitro. In this paper, we will review techniques from both stem cell biology and bioengineering which have been fruitfully combined and have fueled advances in the cardiovascular disease field. We will provide a brief introduction to CVD, reviewing some of the recent studies as related to the role of endothelial cells and endothelial cell dysfunction. Recent advances and the techniques widely used in both bioengineering and stem cell biology will be discussed, providing a broad overview of the collaboration between these two fields and their overall impact on tissue engineering in the cardiovascular devices and implications for treatment of cardiovascular disease.

Cardiovascular health metrics and diabetic nephropathy: a nationally representative cross-sectional study

BACKGROUND

The pathogenesis of diabetic nephropathy is well-documented to be multifactorial. However, research available on the association between cardiovascular health and diabetic nephropathy is limited. Thus, this study aimed to investigate these potential associations and provide guidance for disease prevention.

METHODS

We applied Life's Essential 8 (LE8) identified by the American Heart Association, which integrates multiple health behaviors and health factors to measure cardiovascular health. This study covered 4207 adults with diabetes from the National Health and Nutrition Examination Survey spanning 2007-2018. Weighted regression models assessed the estimated effect of LE8 score on the prevalence of diabetic nephropathy as well as their corresponding clinical indicators. Weighted restricted cubic spline models discussed the possible nonlinear dose-response relationships further. Subgroup analyses clarified the effects of other covariates on correlations.

RESULTS

After adjusting for all covariates, participants with moderate or high cardiovascular health showed a decreased prevalence of diabetic nephropathy (odds ratio [OR]:0.52; 95% confidence interval [CI]:0.42-0.63), and also a decrease in the urinary albumin-to-creatinine ratio [UACR] (β: - 0.83; 95% CI:- 1.00 to - 0.65). The prevalence of diabetic nephropathy and the level of UACR tended to decrease linearly as the total LE8 score increased (P for nonlinear > 0.05). Subgroup analyses showed that the effects of increased overall LE8 score and the specific cardiovascular health construct varied across age and obesity strata.

CONCLUSION

Elevated overall LE8 score was significantly associated with a lower prevalence of diabetic nephropathy in U.S. adults, and the effects of the specific cardiovascular health construct on diabetic nephropathy and their corresponding clinical indicators varied. In all, maintaining good cardiovascular health by refining LE8 metrics may help reduce the adverse effects.

EASIX is an effective marker in predicting mortality of traumatic brain injury patients

BACKGROUND

The Endothelial Activation and Stress Index (EASIX) is a novel marker of endothelial injury and correlates with survival of various patients. The endothelial dysfunction plays an important role on the pathophysiological process of traumatic brain injury (TBI). This study was designed to explore the prognostic value of EASIX on TBI patients.

METHODS

358 TBI patients hospitalized in the West China hospital between October 2018 and October 2022 were enrolled for this study. The EASIX was calculated based on the formula: lactate dehydrogenase (U/L) × creatinine (mg/dL)/platelets (109 cells/L). The univariate and multivariate logistic regression with forward method was performed to explore the association between EASIX and mortality. A prognostic model was developed combining significant risk factors in the multivariate logistic regression. The receiver operating characteristic (ROC) curve was used to compare the predictive accuracy of the EASIX and the developed model.

RESULTS

The 30-day mortality of enrolled 358 TBI patients was 51.1%. Non-survivors had higher EASIX than survivors (p < 0.001). The multivariate logistic regression confirmed seven risk factors for mortality of TBI including injury mechanism (p = 0.010), GCS (p < 0.001), glucose (p < 0.001), EASIX (p = 0.017), subdural hematoma (p = 0.012), coagulopathy (p = 0.001). The AUC of EASIX, SOFA, GCS was 0.747, 0.748 and 0.774, respectively. The AUC of developed predictive model was 0.874 with the sensitivity of 0.913 and specificity of 0.686.

CONCLUSIONS

The EASIX is a reliable marker for predicting mortality of TBI patients. The predictive model incorporating EASIX is helpful for clinicians to evaluate the mortality risk of TBI patients.

Sirt7/HIC1 complex participates in hyperglycaemia-mediated EndMT via modulation of SDC1 expression in diabetic kidney disease and metabolic memory

Diabetic kidney disease (DKD), a primary microvascular complication arising from diabetes, may result in end-stage renal disease. Epigenetic regulation of endothelial mesenchymal transition (EndMT) has been recently reported to exert function in metabolic memory and DKD. Here, we investigated the mechanism which Sirt7 modulated EndMT in human glomerular endothelial cells (HGECs) in the occurrence of metabolic memory in DKD. Lower levels of SDC1 and Sirt7 were noted in the glomeruli of both DKD patients and diabetes-induced renal injury rats, as well as in human glomerular endothelial cells (HGECs) with high blood sugar. Endothelial-to-mesenchymal transition (EndMT) was sustained despite the normalization of glycaemic control. We also found that Sirt7 overexpression associated with glucose normalization promoted the SDC1 expression and reversed EndMT in HGECs. Furthermore, the sh-Sirt7-mediated EndMT could be reversed by SDC1 overexpression. The ChIP assay revealed enrichment of Sirt7 and H3K18ac in the SDC1 promoter region. Furthermore, hypermethylated in cancer 1 (HIC1) was found to be associated with Sirt7. Overexpression of HIC1 with normoglycaemia reversed high glucose-mediated EndMT in HGECs. The knockdown of HIC1-mediated EndMT was reversed by SDC1 upregulation. In addition, the enrichment of HIC1 and Sirt7 was observed in the same promoter region of SDC1. The overexpressed Sirt7 reversed EndMT and improved renal function in insulin-treated diabetic models. This study demonstrated that the hyperglycaemia-mediated interaction between Sirt7 and HIC1 exerts a role in the metabolic memory in DKD by inactivating SDC1 transcription and mediating EndMT despite glucose normalization in HGECs.

The therapeutic effect of mesenchymal stem cells in diabetic kidney disease

Diabetes mellitus (DM) often causes chronic kidney damage despite best medical practices. Diabetic kidney disease (DKD) arises from a complex interaction of factors within the kidney and the whole body. Targeting specific disease-causing agents using drugs has not been effective in treating DKD. However, stem cell therapies offer a promising alternative by addressing multiple disease pathways and promoting kidney regeneration. Mesenchymal stem cells (MSCs) offer great promise due to their superior accessibility ratio from adult tissues and remarkable modes of action, such as the production of paracrine anti-inflammatory and cytoprotective substances. This review critically evaluates the development of MSC treatment for DKD as it moves closer to clinical application. Results from animal models suggest that systemic MSC infusion may positively impact DKD progression. However, few registered and completed clinical trials exist, and whether the treatments are effective in humans is still being determined. Significant knowledge gaps and research opportunities exist, including establishing the ideal source, dose, and timing of MSC delivery, better understanding of in vivo mechanisms, and developing quantitative indicators to obtain a more significant therapeutic response. This paper reviews recent literature on using MSCs in preclinical and clinical trials in DKD. Potent biomarkers related to DKD are also highlighted, which may help better understand MSCs' action in this disease progression. KEY MESSAGES: Mesenchymal stem cells have anti-inflammatory and paracrine effects in diabetic kidney disease. Mesenchymal stem cells alleviate in animal models having diabetic kidney disease. Mesenchymal stem cells possess promise for the treatment of diabetic kidney disease.

The therapeutic effect of mesenchymal stem cells in diabetic kidney disease

Abstract

Diabetes mellitus (DM) often causes chronic kidney damage despite best medical practices. Diabetic kidney disease (DKD) arises from a complex interaction of factors within the kidney and the whole body. Targeting specific disease-causing agents using drugs has not been effective in treating DKD. However, stem cell therapies offer a promising alternative by addressing multiple disease pathways and promoting kidney regeneration. Mesenchymal stem cells (MSCs) offer great promise due to their superior accessibility ratio from adult tissues and remarkable modes of action, such as the production of paracrine anti-inflammatory and cytoprotective substances. This review critically evaluates the development of MSC treatment for DKD as it moves closer to clinical application. Results from animal models suggest that systemic MSC infusion may positively impact DKD progression. However, few registered and completed clinical trials exist, and whether the treatments are effective in humans is still being determined. Significant knowledge gaps and research opportunities exist, including establishing the ideal source, dose, and timing of MSC delivery, better understanding of in vivo mechanisms, and developing quantitative indicators to obtain a more significant therapeutic response. This paper reviews recent literature on using MSCs in preclinical and clinical trials in DKD. Potent biomarkers related to DKD are also highlighted, which may help better understand MSCs’ action in this disease progression.

Key messages

Parallelism and non-parallelism in diabetic nephropathy and diabetic retinopathy

Diabetic nephropathy (DN) and diabetic retinopathy (DR), as microvascular complications of diabetes mellitus, are currently the leading causes of end-stage renal disease (ESRD) and blindness, respectively, in the adult working population, and they are major public health problems with social and economic burdens. The parallelism between the two in the process of occurrence and development manifests in the high overlap of disease-causing risk factors and pathogenesis, high rates of comorbidity, mutually predictive effects, and partial concordance in the clinical use of medications. However, since the two organs, the eye and the kidney, have their unique internal environment and physiological processes, each with specific influencing molecules, and the target organs have non-parallelism due to different pathological changes and responses to various influencing factors, this article provides an overview of the parallelism and non-parallelism between DN and DR to further recognize the commonalities and differences between the two diseases and provide references for early diagnosis, clinical guidance on the use of medication, and the development of new drugs.

Potential role for vitamin D vs. intermittent fasting in controlling aquaporin-1 and aquaporin-3 expression in HFD-induced urinary bladder alterations in rats

Background: High-fat diet-induced obesity is linked to suppression of aquaporins (AQPs) expression in different tissues. Both vitamin D and intermittent fasting were identified to enhance AQPs expression. In the urinary bladder, AQP-1 and AQP-3 mRNA transcripts were identified. Vitamin D has an impact on a variety of genes that encode proteins that control cell proliferation, differentiation, and death. Aim: To assess potential benefits of vitamin D and intermittent fasting (IF) and to explore alterations to the urinary bladder triggered by high-fat diet (HFD) in a rat model of obesity. Methods: Each of the 4 groups contained six adult male albino rats; control: a standard rodent chew for 12 weeks, HFD: HFD and fructose were administered orally via gastric gavage for 12 weeks, and vitamin D: HFD and fructose were administered orally for 8 weeks, then 4 weeks of intraperitoneal injection of vitamin D (5 microns/Kg/2 days) and IF group: Received intraperitoneal injections of vitamin D (5 microns/Kg/2 days) for 4 weeks after consumption of HFD and fructose orally for 8 weeks. The serum lipid profile was conducted at end of the experiment. In the bladder homogenates, the levels of oxidative stress indicators were assessed. Quantitative real-time PCR was performed on recently collected bladder samples. AQP-1 and AQP-3 immunohistochemistry was done. Results: When compared to the HFD group, the vitamin D and IF groups both demonstrated a substantial improvement in histopathological, immunohistochemical, biochemical, and molecular markers. Conclusion: In all examined parameters, IF exceeded vitamin D as a preventive factor for the urinary bladder deterioration.

Cannabinoid receptor 2 (CB2) agonists and L-arginine ameliorate diabetic nephropathy in rats by suppressing inflammation and fibrosis through NF-κβ pathway

Diabetic nephropathy (DN) is a condition that leads to end-stage chronic kidney disease characterized by inflammation and a deficiency of nitric oxide (NO). Cannabinoid receptor (CB2) activation by specific agonist reduces nuclear factor kappa beta (NF-κβ) expression. Beta caryophyllene (BCP), a natural CB2 receptor activator, protects kidney function in several diseases. L-Arginine (LA) modulates several physiological processes by donating nitric oxide (NO). Hence, we tested a novel BCP-LA combination to treat DN and investigated its molecular mechanisms. BCP, LA, and combinations of both were evaluated in LPS-induced RAW 264.7 macrophage inflammation as well as in streptozotocin (55 mg/kg)-induced diabetes in SD rats. Diabetic rats were administered 200 mg/kg of BCP, 100 mg/kg of LA, and combination of both orally for 28 days. Biochemical markers and inflammatory cytokines were assessed in plasma; also, kidney tissue was examined for renal oxidative stress injury, NF-κβ expression, and histology. After 28 days of treatment, BCP and LA combination significantly lowered plasma glucose levels than the disease control group. BCP and LA also normalized renal markers and oxidative stress of diabetic rats. Plasma and RAW macrophage cell lines showed reduced levels of IL-6 and TNF-α (P < 0.001). Histopathological evaluations revealed that BCP and LA together decreased renal fibrosis and collagen deposition also improved nephrotic indices. Meanwhile, the effect of BCP and LA together significantly reduced the NF-κβ (P < 0.01) against diabetic rats. These results indicate that the innovative regimen BCP with LA may be a therapeutic treatment for DN, as it protects kidney tissue from diabetes via NF-κβ inhibition.

Evaluation of Selected Markers in Kidneys of Cynomolgus Monkey (Macaca fascicularis) with Induced Diabetes during Renal Ischemia-reperfusion Injury

We previously reported that induced type 1 diabetes mellitus (DM) increases the susceptibility of acute kidney injury in- duced by ischemia-reperfusion injury (IRI) in cynomolgus monkeys. In this follow-up study, we compared the expression of selected markers in the renal tissues of monkeys subjected to bilateral renal IRI with and without diabetes. All tissues were obtained from the original study. Renal biopsies were obtained before and 24 and 48 h after ischemia and were examined for expression of KI-67 (tubular proliferation), Na+ /K+ ATPase (sodium-potassium pump), TNF-α(tumor necrosis factor-α, inflammation), CD31 (microvessels), CD3 (T-cells), 2 fibrotic markers (fibroblast specific protein-1, FSP-1;α-smooth muscle actin,α -SMA), and cleaved caspase 3 (apoptosis). Generally, the expression of these markers differed in monkeys with and without DM. As compared with non-DM monkeys, DM monkeys had more cells that expressed KI-67 during progression of acute kidney injury (AKI). Na+ /K+ ATPase expression was clearly present at baseline in the basolateral tubular areas only in the non-DM monkeys. At 48 h, its expression in the basolateral area was not visible in DM monkeys, but was still present in intercellular junctions of non-DM monkeys. The expression of TNF-αwas higher in DM before and 48 h after ischemia. Before and 24 h after ischemia, the number of CD31-positive capillaries was not different between 2 groups, although more collapsed vessels were found at in DM at 24 h. At 48 h, the number of capillaries was less in DM compared with those from non-DM animals. DM monkeys had more interstitial CD3-positive cells than did non-DM monkeys at 24 and 48 h after ischemia. Finally, FSP-1-stained cells were more abundant in DM than non-DM at 24 and 48 h. Our results show that DM aggravates the recovery of renal ischemia/reperfusion injury by affecting tubular proliferation, capillary density, T cell infil- tration and by altering protein and mRNA expression of various genes involved in ion channel, inflammation, and fibrotic change. The results from this observational study demonstrate that DM aggravates the recovery of renal ischemia/reperfusion injury by affecting multiple events including tubular necrosis, proliferation, function, inflammation and by inducing capillary rarefaction in cynomolgus monkeys.

IgG N-glycans are associated with prevalent and incident complications of type 2 diabetes

AIMS/HYPOTHESIS

Inflammation is important in the development of type 2 diabetes complications. The N-glycosylation of IgG influences its role in inflammation. To date, the association of plasma IgG N-glycosylation with type 2 diabetes complications has not been extensively investigated. We hypothesised that N-glycosylation of IgG may be related to the development of complications of type 2 diabetes.

METHODS

In three independent type 2 diabetes cohorts, plasma IgG N-glycosylation was measured using ultra performance liquid chromatography (DiaGene n = 1815, GenodiabMar n = 640) and mass spectrometry (Hoorn Diabetes Care Study n = 1266). We investigated the associations of IgG N-glycosylation (fucosylation, galactosylation, sialylation and bisection) with incident and prevalent nephropathy, retinopathy and macrovascular disease using Cox- and logistic regression, followed by meta-analyses. The models were adjusted for age and sex and additionally for clinical risk factors.

RESULTS

IgG galactosylation was negatively associated with prevalent and incident nephropathy and macrovascular disease after adjustment for clinical risk factors. Sialylation was negatively associated with incident diabetic nephropathy after adjustment for clinical risk factors. For incident retinopathy, similar associations were found for galactosylation, adjusted for age and sex.

CONCLUSIONS

We showed that IgG N-glycosylation, particularly galactosylation and to a lesser extent sialylation, is associated with a higher prevalence and future development of macro- and microvascular complications of diabetes. These findings indicate the predictive potential of IgG N-glycosylation in diabetes complications and should be analysed further in additional large cohorts to obtain the power to solidify these conclusions.

The unique structural and functional characteristics of glomerular endothelial cell fenestrations and their potential as a therapeutic target in kidney disease

Glomerular endothelial cell (GEnC) fenestrations are a critical component of the glomerular filtration barrier. Their unique nondiaphragmed structure is key to their function in glomerular hydraulic permeability, and their aberration in disease can contribute to loss of glomerular filtration function. This review provides a comprehensive update of current understanding of the regulation and biogenesis of fenestrae. We consider diseases in which GEnC fenestration loss is recognized or may play a role and discuss methods with potential to facilitate the study of these critical structures. Literature is drawn from GEnCs as well as other fenestrated cell types such as liver sinusoidal endothelial cells that most closely parallel GEnCs.

Sodium Butyrate as Key Regulator of Mitochondrial Function and Barrier Integrity of Human Glomerular Endothelial Cells

The gut microbiota has emerged as an important modulator of cardiovascular and renal homeostasis. The composition of gut microbiota in patients suffering from chronic kidney disease (CKD) is altered, where a lower number of bacteria producing short chain fatty acids (SCFAs) is observed. It is known that SCFAs, such as butyrate and acetate, have protective effects against cardiovascular diseases and CKD but their mechanisms of action remain largely unexplored. In the present study, we investigated the effect of butyrate and acetate on glomerular endothelial cells. Human glomerular microvascular endothelial cells (hgMVECs) were cultured and exposed to butyrate and acetate and their effects on cellular proliferation, mitochondrial mass and metabolism, as well as monolayer integrity were studied. While acetate did not show any effects on hgMVECs, our results revealed that butyrate reduces the proliferation of hgMVECs, strengthens the endothelial barrier through increased expression of VE-cadherin and Claudin-5 and promotes mitochondrial biogenesis. Moreover, butyrate reduces the increase in oxygen consumption induced by lipopolysaccharides (LPS), revealing a protective effect of butyrate against the detrimental effects of LPS. Taken together, our data show that butyrate is a key player in endothelial integrity and metabolic homeostasis.

Association Between Endothelial Activation and Stress Index and 28-Day Mortality in Septic ICU patients: a Retrospective Cohort Study

Background: Endothelial Activation and Stress Index (EASIX) is a reliable alternative biomarker of endothelial dysfunction. Because endothelial activation is involved in sepsis pathophysiology, we aimed to investigate the association between EASIX and prognosis in septic patients. Methods: Data were extracted from the Medical Information Mart for Intensive Care (MIMIC) IV database. EASIX scores were calculated using the formula: lactate dehydrogenase (U/L) × creatinine (mg/dL)/platelet count (109/L). Patients were grouped into tertiles according to log2 transformed EASIX. The primary and secondary outcomes were 28-day and 90-day mortality. Cox proportional hazards models, Kaplan-Meier curves, restricted cubic spline curves, and subgroup analyses were conducted to evaluate the association between EASIX and prognosis in septic patients. Results: A total of 7504 patients were included. Multivariable Cox proportional hazards analyses showed that higher log2-EASIX was associated with increased risk of 28-day mortality (HR, 1.10; 95% CI, 1.07-1.13; P < 0.001). Compared with tertile 1, the tertile 2 and 3 groups had higher risk of 28-day mortality [HR (95% CI) 1.24 (1.09-1.41); HR (95% CI) 1.51 (1.31-1.74)]; P for trend < 0.001). Similar results were found for 90-day mortality. Kaplan-Meier curves showed that patients with higher EASIX had lower 28-day and 90-day survival rates. A linear relationship was found between log2-EASIX and 28-day and 90-day mortality. Conclusion: High EASIX was significantly associated with an increased risk of 28-day and 90-day all-cause mortality in patients with sepsis.

Ferroptosis in diabetic nephropathy: Mechanisms and therapeutic implications

Diabetic Nephropathy (DN), the most common complication in diabetes mellitus, has been affecting the lives of people diabetic for a long time. Numerous studies have demonstrated the unbreakable connection between ferroptosis and kidney cell damage. Ferroptosis is a type of iron-dependent, non-apoptotic, regulated cell death, characterized by the buildup of intracellular lipid peroxides to lethal levels. Although the role of programmed cell deaths like apoptosis, autophagy, and necroptosis in the pathogenesis of DN has been demonstrated, the implication of ferroptosis in DN was least interrogated. Hence, the main aim of this review was to discuss the current understanding of ferroptosis focusing on its potential mechanisms, its involvement in DN, and emerging therapeutic opportunities.

Diabetic Retinopathy and Dementia Association, Beyond Diabetes Severity

PURPOSE

To investigate whether associations between diabetic retinopathy (DR) and dementia and Alzheimer's disease (AD) remain significant after controlling for several measures of diabetes severity.

DESIGN

Retrospective cohort study.

METHODS

Adult Changes in Thought (ACT) is a prospective cohort study of adults aged ≥65 years, randomly selected and recruited from the membership rolls of Kaiser Permanente Washington, who are dementia free at enrollment and followed biennially until incident dementia. The ACT participants were included in this study if they had type 2 diabetes mellitus at enrollment or developed it during follow-up, and data were collected through September, 2018 (3516 person-years of follow-up). Diabetes was defined by ≥ 2 diabetes medication fills in 1 year. Diagnosis of DR was based on International Classification of Diseases Ninth and Tenth Revision codes. Estimates of microalbuminuria, long-term glycemia, and renal function from longitudinal laboratory records were used as indicators of diabetes severity. Alzheimer's disease and dementia were diagnosed using research criteria at expert consensus meetings.

RESULTS

A total of 536 participants (median baseline age 75 [interquartile range 71-80], 54% women) met inclusion criteria. Significant associations between DR >5 years duration with dementia (hazard ratio 1.81 [95% CI 1.23, 2.65]) and AD (1.80 [1.15, 2.82]) were not altered by adjustment for estimates of microalbuminuria, long-term glycemia, and renal function (dementia: 1.69 [1.14, 2.50]; AD: 1.73 [1.10, 2.74]).

CONCLUSIONS

Among people with type 2 diabetes, DR itself appears to be an important biomarker of dementia risk in addition to glycemia and renal complications.

Vaccinium as Potential Therapy for Diabetes and Microvascular Complications

Diabetes mellitus is one of the most critical global health concerns, with a fast-growing prevalence. The incidence of diabetic vascular complications is also rapidly increasing, exacerbating the burden on individuals with diabetes and the consumption of public medical resources. Despite the overall improvements in the prevention, diagnosis, and treatment of diabetic microvascular complications in recent years, safe and effective alternative or adjunctive therapies are urgently needed. The mechanisms underlying diabetic vascular complications are complex, with hyperglycemia-induced oxidative stress and inflammation being the leading causes. Therefore, glycemic control, antioxidation, and anti-inflammation are considered the main targets for the treatment of diabetes and its vascular comorbidities. Vaccinium L. (Ericaceae) is a genus of plants enriched with polyphenolic compounds in their leaves and fruits. Vaccinium and its extracts have demonstrated good bioactivity in reducing blood glucose, oxidative stress, and inflammation, making them excellent candidates for the management of diabetes and diabetic vascular complications. Here, we review recent preclinical and clinical studies on the potential effect of Vaccinium on ameliorating diabetes and diabetic complications, particularly diabetic kidney disease and diabetic retinopathy.

Treatment effects of soluble guanylate cyclase modulation on diabetic kidney disease at single-cell resolution

Diabetic kidney disease (DKD) is the most common cause of renal failure. Therapeutics development is hampered by our incomplete understanding of animal models on a cellular level. We show that ZSF1 rats recapitulate human DKD on a phenotypic and transcriptomic level. Tensor decomposition prioritizes proximal tubule (PT) and stroma as phenotype-relevant cell types exhibiting a continuous lineage relationship. As DKD features endothelial dysfunction, oxidative stress, and nitric oxide depletion, soluble guanylate cyclase (sGC) is a promising DKD drug target. sGC expression is specifically enriched in PT and stroma. In ZSF1 rats, pharmacological sGC activation confers considerable benefits over stimulation and is mechanistically related to improved oxidative stress regulation, resulting in enhanced downstream cGMP effects. Finally, we define sGC gene co-expression modules, which allow stratification of human kidney samples by DKD prevalence and disease-relevant measures such as kidney function, proteinuria, and fibrosis, underscoring the relevance of the sGC pathway to patients.

Factors Predictive of Development of Acute Kidney Injury in Patients With COVID-19 in Brunei Darussalam

INTRODUCTION

Acute kidney injury (AKI) in coronavirus disease 2019 (COVID-19) patients affects their health outcomes. Incidence and outcomes varied in the literature, particularly with different population and epidemiological demographics. Data remain scarce in the Southeast Asia region. We report the incidence, outcomes, pattern, types of AKI, and factors that influence AKI patient outcomes in Brunei Darussalam.

METHODS

All patients (N = 930) with COVID-19 who were admitted to the National Isolation Center (between 7th August 2021 and 30thSeptember 2021) were included in the study. The confirmation of AKI was based on the KDIGO (Kidney Disease Improving Global Outcomes) criteria.

RESULTS

The mean age of the patients was 41.9 ± 14.4 years with diabetes mellitus (DM), hypertension (HT), and chronic kidney disease (CKD) accounting for 11.7%, 29.1%, and 4.8% of comorbidities, respectively. Overall, 109 (11.7%) had AKI (KDIGO Stage 1 [67.9%], 2 [13.8%], and 3 [18.3%]), while 75.2% of the cases occurred pre-admission and 26.6% were cases of acute exacerbation of CKD. Univariate analysis identified age (odd ratio [OR] 1.06), male gender (OR 1.63), local nationality (OR 8.03), DM (OR 4.44), HT (OR 5.29), vascular disease (OR 6.08), presence of gastrointestinal symptoms (OR 2.08), antibiotic (OR 3.70) and nephrotoxins exposures (OR 8.57) as significant variables. Multivariate analysis showed age (adjusted OR [AOR] 1.04), male gender (AOR 1.67), gastrointestinal symptoms (AOR 1.61), antibiotic (AOR 2.34), and nephrotoxins exposure (AOR 4.73) as significant.

CONCLUSIONS

Our study showed that one in nine patients with COVID-19 developed AKI with almost a third having stages 2 and 3 AKI. Older age, male gender, presence of GI symptoms, and antibiotic and nephrotoxin exposures were significant predictors of AKI. Patients with these factors should be prioritized for admission and treatment. Even though manifestations are generally now less severe, findings from this study can guide the management of COVID-19 as the disease enters the endemic stage. Furthermore, lessons learned from the COVID-19 pandemic will provide useful information and knowledge for future viral outbreaks or pandemics.

Klotho, Oxidative Stress, and Mitochondrial Damage in Kidney Disease

Reducing oxidative stress stands at the center of a prevention and control strategy for mitigating cellular senescence and aging. Kidney disease is characterized by a premature aging syndrome, and to find a modulator targeting against oxidative stress, mitochondrial dysfunction, and cellular senescence in kidney cells could be of great significance to prevent and control the progression of this disease. This review focuses on the pathogenic mechanisms related to the appearance of oxidative stress damage and mitochondrial dysfunction in kidney disease. In this scenario, the anti-aging Klotho protein plays a crucial role by modulating signaling pathways involving the manganese-containing superoxide dismutase (Mn-SOD) and the transcription factors FoxO and Nrf2, known antioxidant systems, and other known mitochondrial function regulators, such as mitochondrial uncoupling protein 1 (UCP1), B-cell lymphoma-2 (BCL-2), Wnt/β-catenin, peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1 alpha), transcription factor EB, (TFEB), and peroxisome proliferator-activated receptor gamma (PPAR-gamma). Therefore, Klotho is postulated as a very promising new target for future therapeutic strategies against oxidative stress, mitochondria abnormalities, and cellular senescence in kidney disease patients.

PLVAP as an Early Marker of Glomerular Endothelial Damage in Mice with Diabetic Kidney Disease

Plasmalemma vesicle-associated protein (PLVAP) is the main component of endothelial diaphragms in fenestrae, caveolae, and transendothelial channels. PLVAP is expressed in the adult kidney glomerulus upon injury. Glomerular endothelial injury is associated with progressive loss of kidney function in diabetic kidney disease (DKD). This study aimed to investigate whether PLVAP could serve as a marker for glomerular endothelial damage in DKD. Glomerular PLVAP expression was analyzed in different mouse models of DKD and their respective healthy control animals using automatic digital quantification of histological whole kidney sections. Transgenic mice expressing a dominant-negative GIP receptor (GIPR^dn) in pancreatic beta-cells as a model for diabetes mellitus (DM) type 1 and black and tan brachyuric (BTBR) ob/ob mice, as a model for DM type 2, were used. Distinct PLVAP induction was observed in all diabetic models studied. Traces of glomerular PLVAP expression could be identified in the healthy control kidneys using automated quantification. Stainings for other endothelial injury markers such as CD31 or the erythroblast transformation-specific related gene (ERG) displayed no differences between diabetic and healthy groups at the time points when PLVAP was induced. The same was also true for the mesangial cells marker α8Integrin, while the podocyte marker nephrin appeared to be diminished only in BTBR ob/ob mice. Glomerular hypertrophy, which is one of the initial morphological signs of diabetic kidney damage, was observed in both diabetic models. These findings suggest that PLVAP is an early marker of glomerular endothelial injury in diabetes-induced kidney damage in mice.

A Cyclopentanone Compound Attenuates the Over-Accumulation of Extracellular Matrix and Fibrosis in Diabetic Nephropathy via Downregulating the TGF-β/p38MAPK Axis

Excessive accumulation of the extracellular matrix (ECM) is a crucial pathological process in chronic kidney diseases, such as diabetic nephropathy, etc. The underlying mechanisms of how to decrease ECM deposition to improve diabetic nephropathy remain elusive. The present study investigated whether cyclopentanone compound H8 alleviated ECM over-deposition and fibrosis to prevent and treat diabetic nephropathy. HK-2 cell viability after treatment with H8 was measured by an MTT assay. ECM alterations and renal fibrosis were identified in vitro and in vivo. A pharmacological antagonist was used to detect associations between H8 and the p38 mitogen-activated protein kinase (p38MAPK) signaling pathway. H8 binding was identified through computer simulation methods. Studies conducted on high glucose and transforming growth factor β1 (TGF-β1)-stimulated HK-2 cells revealed that the p38MAPK inhibitor SB 202190 and H8 had similar pharmacological effects. In addition, excessive ECM accumulation and fibrosis in diabetic nephropathy were remarkably improved after H8 administration in vivo and in vitro. Finally, the two molecular docking models further proved that H8 is a specific p38MAPK inhibitor that forms a hydrogen bond with the LYS-53 residue of p38MAPK. The cyclopentanone compound H8 alleviated the over-deposition of ECM and the development of fibrosis in diabetic nephropathy by suppressing the TGF-β/p38MAPK axis.

The Effect of Allograft Inflammatory Factor-1 on Inflammation, Oxidative Stress, and Autophagy via miR-34a/ATG4B Pathway in Diabetic Kidney Disease

Increasing evidence suggests that disorders of inflammation, oxidative stress, and autophagy contribute to the pathogenesis of diabetic kidney disease (DKD). This study attempted to clarify the effect of allograft inflammatory factor-1 (AIF-1), miR-34a, and ATG4B on inflammation, oxidative stress, and autophagy in DKD both in vitro and in vivo experiments. In vivo, it was found that the levels of AIF-1, miR-34a, oxidative stress, and inflammatory factors were significantly increased in blood and urine samples of DKD patients and mouse models and correlated with the level of urinary protein. In vitro, it was also found that the expressions of AIF-1, miR-34a, ROS, and inflammatory factors were increased, while ATG4B and other autophagy related proteins were decreased in human renal glomerular endothelial cells (HRGECs) cultured with high concentration glucose medium (30 mmol/L). When AIF-1 gene was overexpressed, the levels of miR-34a, ROS, and inflammatory factors were significantly upregulated, and autophagy-related proteins such as ATG4B were downregulated, while downregulation of AIF-1 gene had the opposite effect. In addition, miR-34a inhibited the expression of ATG4B and autophagy-related proteins and increased the levels of ROS and inflammation. Furthermore, the result of luciferase reporter assay suggested that ATG4B was the target gene of miR-34a. When ATG4B gene was overexpressed, the level of autophagy was upregulated, and inflammatory factors were downregulated. Conversely, when ATG4B gene was inhibited, the level of autophagy was downregulated, and inflammatory factors were upregulated. Then, autophagy inducers inhibited the levels of inflammation and ROS, whereas autophagy inhibitors had the opposite function in HRGECs induced by glucose (30 mmol/L). In conclusion, the above data suggested that AIF-1 regulated the levels of inflammation, oxidative stress, and autophagy in HRGECs via miR-34a/ATG4B pathway to contribute to the pathogenesis of diabetic kidney disease.

Resistant Starch as a Dietary Intervention to Limit the Progression of Diabetic Kidney Disease

Diabetes is the leading cause of kidney disease, and as the number of individuals with diabetes increases there is a concomitant increase in the prevalence of diabetic kidney disease (DKD). Diabetes contributes to the development of DKD through a number of pathways, including inflammation, oxidative stress, and the gut-kidney axis, which may be amenable to dietary therapy. Resistant starch (RS) is a dietary fibre that alters the gut microbial consortium, leading to an increase in the microbial production of short chain fatty acids. Evidence from animal and human studies indicate that short chain fatty acids are able to attenuate inflammatory and oxidative stress pathways, which may mitigate the progression of DKD. In this review, we evaluate and summarise the evidence from both preclinical models of DKD and clinical trials that have utilised RS as a dietary therapy to limit the progression of DKD.

Association of retinal fractal dimension and vessel tortuosity with impaired renal function among healthy Chinese adults

Purpose

This study investigated the association of retinal fractal dimension (FD) and blood vessel tortuosity (BVT) with renal function [assessed by estimated glomerular filtrate rate (eGFR)] in healthy Chinese adults using swept-source optical coherence tomographic angiography (SS-OCTA).

Materials and methods

This cross-sectional study was conducted among ocular treatment–naïve healthy participants from Guangzhou, China. FD and BVT in the superficial capillary plexus and deep capillary plexus were measured by SS-OCTA with a 3 × 3 macula model. eGFR was calculated using the Xiangya equation, and impaired renal function (IRF) was defined as eGFR = 90 mL/min/1.73 m2. Linear regression was performed to evaluate the relationships between SS-OCTA metrics and renal function.

Results

A total of 729 participants with a mean age of 57.6 ± 9.1 years were included in the final analysis. Compared to participants with normal renal function, those with IRF had lower FD both in the superficial capillary plexus (1.658 ± 0.029 vs. 1.666 ± 0.024, p = 0.001) and deep capillary plexus (1.741 ± 0.016 vs. 1.746 ± 0.016, p = 0.0003), while the deep BVT was larger in participants with IRF than those with normal renal function (1.007 ± 0.002 vs. 1.006 ± 0.002, p = 0.028). The superficial FD was linearly and positively associated with eGFR after adjusting for confounders (β = 0.2257; 95% CI 0.0829–0.3685; p = 0.002), while BVT was not associated with eGFR (all p ≥ 0.05).

Conclusion

The patients with IRF had lower FD and larger BVT than those with normal renal function. The superficial FD decreased linearly with renal function deterioration. Our study suggests that the retinal microvasculature can represent a useful indicator of subclinical renal microvascular abnormalities and serve as a useful non-invasive assessment to predict and monitor the progression of renal function.

lncRNA MALAT1 Promotes Diabetic Nephropathy Progression via miR-15b-5p/TLR4 Signaling Axis

Objective

The long noncoding RNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) are closely associated with the pathogenesis of diabetic nephropathy (DN). But a complete mechanism for MALAT1 in DN has yet to be identified. This study investigated the effect of MALAT1 on DN through the regulation of miR-15b-5p/TLR4 signaling.

Method

Renal tissues were collected from DN patients. Human renal tubular epithelial cells (HK-2) were used as a model of DN induced by high glucose (HG). We then measured the viability, apoptosis, and inflammatory cytokine levels of HK-2 cells using the corresponding assays. Following transfections of si-MALAT1, si-MALAT1+miR-15b-5p inhibitor, or si-MALAT1+vector TLR4 into HG-stimulated HK-2 cells, cell viability, apoptosis, and inflammatory cytokines were again measured. Furthermore, dual-luciferase reporter assay validated the interactions of MALAT1/miR-15b-5p and miR-15b-5p/TLR4. In addition, the interaction between MALAT1 and miR-15b-5p was investigated by RNA immunoprecipitation (RIP).

Results

A significant upregulation of MALAT1 was observed in DN kidney tissues, as well as in HG-stimulated HK-2 cells. MALAT1 knockdown attenuates the inhibition of cell viability, apoptosis, and inflammatory response induced by HG in HK-2 cells. Moreover, a miR-15b-5p inhibitor or TLR4 overexpression reversed the above effects induced by MALAT1 knockdown.

Conclusion

These results indicate that reduced MALAT1 ameliorates HG-stimulated HK-2 cell damage through an inhibition of the miR-15b-5p/TLR4 axis. MALAT1 may serve as a biomarker and potential therapeutic target for DN.

Sinomenine alleviates glomerular endothelial permeability by activating the C/EBP-α/claudin-5 signaling pathway

Diabetic nephropathy (DN) is one of the main complications of diabetes. It is closely associated with the dysfunction of glomerular endothelial cells (GECs) under hyperglycemia. Severe inflammation is an important inducer for the development of GECs dysfunction, and it contributes to the disruption of tight junctions in GECs and the increased endothelial permeability. Sinomenine, an alkaloid monomer extracted from the rhizome of Sinomenium acutum, is recognized for its multiple pharmacological functions, including an anti-DN property. The present study aimed to explore the potential functional mechanism of Sinomenine against DN. Animals were randomly divided into Sham, DN, DN + Sinomenine (20 mg/kg), and DN + Sinomenine (40 mg/kg) groups. The Sinomenine or vehicle was administered every day for 6 weeks, followed by collecting renal tissues for further detection. Increased body weights, elevated blood glucose levels and UAE values, aggravated renal tissue pathology, higher concentrations of IL-18 and IL-1β in renal tissues, and reduced claudin-5 expression were observed in DN rats. However, the administration of Sinomenine significantly alleviated all these DN-related changes. Furthermore, human renal glomerular endothelial cells (HrGECs) were treated with high glucose (HG, 30 mM) with or without Sinomenine (50, 100 μM) for 24 h. We found that Sinomenine treatment ameliorated the elevated production of IL-18 and IL-1β, increased fluorescence intensity of FITC-dextran, declined trans-endothelial electrical resistance (TEER) value, and reduction of claudin-5 and C/EBP-α in HG-treated HrGECs. Moreover, the regulatory effect of Sinomenine on endothelial monolayer permeability in HG-treated HrGECs was abolished by the knockdown of C/EBP-α, indicating C/EBP-α is required for the effect of Sinomenine. We concluded that Sinomenine alleviated diabetic nephropathy-induced renal glomerular endothelial dysfunction via activating the C/EBP-α/claudin-5 axis.

Targeting inflammation for the treatment of Diabetic Kidney Disease: a five-compartment mechanistic model

Diabetic kidney disease (DKD) is the leading cause of kidney failure worldwide. Mortality and morbidity associated with DKD are increasing with the global prevalence of type 2 diabetes. Chronic, sub-clinical, non-resolving inflammation contributes to the pathophysiology of renal and cardiovascular disease associated with diabetes. Inflammatory biomarkers correlate with poor renal outcomes and mortality in patients with DKD. Targeting chronic inflammation may therefore offer a route to novel therapeutics for DKD. However, the DKD patient population is highly heterogeneous, with varying etiology, presentation and disease progression. This heterogeneity is a challenge for clinical trials of novel anti-inflammatory therapies. Here, we present a conceptual model of how chronic inflammation affects kidney function in five compartments: immune cell recruitment and activation; filtration; resorption and secretion; extracellular matrix regulation; and perfusion. We believe that the rigorous alignment of pathophysiological insights, appropriate animal models and pathology-specific biomarkers may facilitate a mechanism-based shift from recruiting ‘all comers’ with DKD to stratification of patients based on the principal compartments of inflammatory disease activity.

Mechanistic Pathogenesis of Endothelial Dysfunction in Diabetic Nephropathy and Retinopathy

Diabetic nephropathy (DN) and diabetic retinopathy (DR) are microvascular complications of diabetes. Microvascular endothelial cells are thought to be the major targets of hyperglycemic injury. In diabetic microvasculature, the intracellular hyperglycemia causes damages to the vascular endothelium, via multiple pathophysiological process consist of inflammation, endothelial cell crosstalk with podocytes/pericytes and exosomes. In addition, DN and DR diseases development are involved in several critical regulators including the cell adhesion molecules (CAMs), the vascular endothelial growth factor (VEGF) family and the Notch signal. The present review attempts to gain a deeper understanding of the pathogenesis complexities underlying the endothelial dysfunction in diabetes diabetic and retinopathy, contributing to the development of new mechanistic therapeutic strategies against diabetes-induced microvascular endothelial dysfunction.

The protective effects of cabozantinib against high glucose-induced damages in in vitro renal glomerular endothelial cells model via inhibition of early growth response-1 (Egr-1)

Cabozantinib is a tyrosine kinase inhibitor with anti-tumor activity in kidney cancer. However, the efficacy of cabozantinib in other renal diseases has never been reported. Here, we focused on exploring the effect of cabozantinib on diabetic nephropathy (DN). The biofunctions of cabozantinib in human renal glomerular endothelial cells (hGECs) under high glucose conditions have been investigated. We found that cabozantinib ameliorated high glucose-induced oxidative stress in hGECs with decreased production of mitochondrial reactive oxygen species (ROS) and increased glutathione peroxidase (GSH-PX) activity. Cabozantinib ameliorated high glucose-induced reduction in the expression of endothelial nitric oxide synthase (eNOS) and the production of nitric oxide (NO) in hGECs. It also suppressed the expression of pro-inflammatory mediators, interleukin-6 (IL-6) and monocyte chemokine protein 1 (MCP-1), against high glucose exposure in hGECs. Cabozantinib reduced the expression of early growth response-1 (Egr-1) in high glucose-treated hGECs, while Egr-1 overexpression abolished the protective effects of cabozantinib against high glucose in hGECs. In conclusion, cabozantinib protected hGECs from high glucose-induced oxidative stress, NO deficiency, and inflammation via regulating Egr-1. These findings suggest that cabozantinib might be used as an adjuvant to control DN.

Effects of soluble guanylate cyclase stimulator on renal function in ZSF-1 model of diabetic nephropathy

BACKGROUND

Diabetic nephropathy is associated with endothelial dysfunction and oxidative stress, in which the nitric oxide-soluble guanylate cyclase-cyclic guanosine monophosphate (NO-sGC-cGMP) signaling pathway is impaired. We hypothesize that sGC stimulator Compound 1 can enhance NO signaling, reduce proteinuria in a diabetic nephropathy preclinical model with diminished NO bioavailability and increased oxidized sGC. Therefore, we evaluated the effect of sGC stimulator Compound 1 on the renal effect in obese ZSF1 (ZSF1 OB) rats.

MATERIALS AND METHODS

The sGC stimulator Compound 1, the standard of care agent Enalapril, and a combination of Compound 1 and Enalapril were administered chronically to obese ZSF1 rats for 6 months. Mean arterial pressure, heart rate, creatinine clearance for glomerular filtration rate (eGFR), urinary protein excretion to creatinine ratio (UPCR), and urinary albumin excretion ratio (UACR) were determined during the study. The histopathology of glomerular and interstitial lesions was assessed at the completion of the study.

RESULTS

While both Compound 1 and Enalapril significantly reduced blood pressure, the combination of Compound 1 and Enalapril normalized blood pressure levels. Compound 1 improved eGFR and reduced UPCR and UACR. A combination of Enalapril and Compound 1 resulted in a marked reduction in UPCR and UACR and improved GFR.

CONCLUSION

The sGC stimulator Compound 1 as a monotherapy slowed renal disease progression, and a combination of the sGC stimulator with Enalapril provided greater renal protection in a rodent model of diabetic nephropathy.

Midazolam Ameliorates Hyperglycemia-Induced Glomerular Endothelial Dysfunction by Inhibiting Transglutaminase 2 in Diabetes

Midazolam is an anesthetic widely used for anxiolysis and sedation; however, to date, a possible role for midazolam in diabetic kidney disease remains unknown. Here, we investigated the effect of midazolam on hyperglycemia-induced glomerular endothelial dysfunction and elucidated its mechanism of action in kidneys of diabetic mice and human glomerular microvascular endothelial cells (HGECs). We found that, in diabetic mice, subcutaneous midazolam treatment for 6 weeks attenuated hyperglycemia-induced elevation in urine albumin/creatinine ratios. It also ameliorated hyperglycemia-induced adherens junction disruption and subsequent microvascular leakage in glomeruli of diabetic mice. In HGECs, midazolam suppressed high glucose-induced vascular endothelial-cadherin disruption and endothelial cell permeability via inhibition of intracellular Ca²⁺ elevation and subsequent generation of reactive oxygen species (ROS) and transglutaminase 2 (TGase2) activation. Notably, midazolam also suppressed hyperglycemia-induced ROS generation and TGase2 activation in glomeruli of diabetic mice and markedly improved pathological alterations in glomerular ultrastructure in these animals. Analysis of kidneys from diabetic Tgm2^−/− mice further revealed that TGase2 played a critical role in microvascular leakage. Overall, our findings indicate that midazolam ameliorates hyperglycemia-induced glomerular endothelial dysfunction by inhibiting ROS-mediated activation of TGase2.

To the Question of Vitamin D Network in Type 1 Diabetes and Diabetic Nephropathy in Children Nursed in Ukrainian Endocrinology Unit

Background

Vitamin D deficiency is a great problem worldwide. Vitamin D plays an essential role in calcium and bone metabolism. Diabetic nephropathy (DN) is a dangerous kidney-related complication of type 1 diabetes (T1D).

Aim of the study

To evaluate levels of Vitamin D3 in pediatric patients with T1D and DN; to study the dependence between the Vitamin D level and main clinical and laboratory parameters of the disease, that is, duration, complications episodes, albuminuria levels, glomerular filtration rate (GFR).

Material and methods

A survey of 72 children with T1D and DN aged 3–17 years was done. Complex examination including conventional methods (physical examination, blood pressure measurement, blood tests, study of urinary sediment, renal ultrasound, etc.) was done for all patients. Data was processed using GraphPad Prism 9.0 Software for Windows (USA, San Diego, CA). p-values <.05 were considered statistically significant.

Results

Majority of patients from T1D group have normal value of Vitamin D, only 27.7% of children have Vitamin D insufficiency. In contrast, in children from DN group only 16.7% of children have Vitamin D insufficiency and 83.3% have Vitamin D deficiency. Vitamin D serum level negatively correlates with disease duration and albuminuria level in the group with DN. Serum levels of Vitamin D positively correlate with GFR in patients with T1D. Patients with DN who had a duration of T1D for 10 years and more have a higher progression rate to Vitamin D deficiency as compared to those who have a T1D duration of less than 10 years.

Conclusions

The authors conclude that Vitamin D has a direct relationship with functional disorders with DN, that is, albuminuria, GFR, kidney function. Further investigations of Vitamin D supplementation on different stages of the ND development and progression are needed.

Endothelial ADAM17 Expression in the Progression of Kidney Injury in an Obese Mouse Model of Pre-Diabetes

Disintegrin and metalloproteinase domain 17 (ADAM17) activates inflammatory and fibrotic processes through the shedding of various molecules such as Tumor Necrosis Factor-α (TNF-α) or Transforming Growht Factor-α (TGF-α). There is a well-recognised link between TNF-α, obesity, inflammation, and diabetes. In physiological situations, ADAM17 is expressed mainly in the distal tubular cell while, in renal damage, its expression increases throughout the kidney including the endothelium. The aim of this study was to characterize, for the first time, an experimental mouse model fed a high-fat diet (HFD) with a specific deletion of Adam17 in endothelial cells and to analyse the effects on different renal structures. Endothelial Adam17 knockout male mice and their controls were fed a high-fat diet, to induce obesity, or standard rodent chow, for 22 weeks. Glucose tolerance, urinary albumin-to-creatinine ratio, renal histology, macrophage infiltration, and galectin-3 levels were evaluated. Results showed that obese mice presented higher blood glucose levels, dysregulated glucose homeostasis, and higher body weight compared to control mice. In addition, obese wild-type mice presented an increased albumin-to-creatinine ratio; greater glomerular size and mesangial matrix expansion; and tubular fibrosis with increased galectin-3 expression. Adam17 deletion decreased the albumin-to-creatinine ratio, glomerular mesangial index, and tubular galectin-3 expression. Moreover, macrophage infiltration in the glomeruli of obese Adam17 knockout mice was reduced as compared to obese wild-type mice. In conclusion, the expression of ADAM17 in endothelial cells impacted renal inflammation, modulating the renal function and histology in an obese pre-diabetic mouse model.

Impaired bone marrow microenvironment and stem cells in transfusion-dependent beta-thalassemia

Beta-thalassemia (BT) is a hereditary disease caused by abnormal hemoglobin synthesis with consequent ineffective erythropoiesis. Patients with thalassemia major are dependent on long-term blood transfusions with associated long-term complications such as iron overload (IO). This excess iron can result in tissue damage, impaired organ function, and increased morbidity. Growing evidence has demonstrated that IO contributes to impairment of the bone marrow (BM) microenvironment that largely impacts the function of BM mesenchymal stem cells, hematopoietic stem cells, and endothelial cells. In this article, we review recent progress in the understanding of iron metabolism and the perniciousness induced by IO. We highlight the importance of understanding the cross-talk between BM stem cells and the BM microenvironment, particularly the pathological effect of IO on BM stem cells and BT-associated complications. We also provide an update on recent novel therapies to cure transfusion-dependent beta-thalassemia and iron overload-induced complications for their future clinical application.

Loss of Functional SCO2 Attenuates Oxidative Stress in Diabetic Kidney Disease

Increased oxidative stress in glomerular endothelial cells (GEnCs) contributes to early diabetic kidney disease (DKD). While mitochondrial respiratory complex IV activity is reduced in DKD, it remains unclear whether this is a driver or a consequence of oxidative stress in GEnCs. Synthesis of cytochrome C oxidase 2 (SCO2), a key metallochaperone in the electron transport chain, is critical to the biogenesis and assembly of subunits required for functional respiratory complex IV activity. Here, we investigated the effects of Sco2 hypomorphs (Sco2 KO/KI , Sco2 KI/KI ), with a functional loss of SCO2, in the progression of DKD using a murine model of Type II Diabetes Mellitus, db/db mice. Diabetic Sco2 KO/KI and Sco2 KI/KI hypomorphs exhibited a reduction in complex IV activity, but an improvement in albuminuria, serum creatinine, and histomorphometric evidence of early DKD as compared to db/db mice. Single-nucleus RNA sequencing with gene set enrichment analysis of differentially expressed genes in the endothelial cluster of Sco2 KO/KI ;db/db mice demonstrated an increase in genes involved in VEGF-VEGFR2 signaling and reduced oxidative stress as compared to db/db mice. These data suggest that reduced complex IV activity due to a loss of functional SCO2 might be protective in GEnCs in early DKD.

Oxidative Stress Genes in Diabetes Mellitus Type 2: Association with Diabetic Kidney Disease

Diabetic type 2 patients compared to nondiabetic patients exhibit an increased risk of developing diabetic kidney disease (DKD), the leading cause of end-stage renal disease. Hyperglycemia, hypertension, oxidative stress (OS), and genetic background are some of the mechanisms and pathways implicated in DKD pathogenesis. However, data on OS pathway susceptibility genes show limited success and conflicting or inconclusive results. Our study is aimed at exploring OS pathway genes and variants which could be associated with DKD. We recruited 121 diabetes mellitus type 2 (DM2) patients with DKD (cases) and 220 DM2, non-DKD patients (control) of Greek origin and performed a case-control association study using genome-wide association data. PLINK and EIGENSOFT were used to analyze the data. Our results indicate 43 single nucleotide polymorphisms with their 21 corresponding genes on the OS pathway possibly contributing or protecting from DKD: SPP1, TPO, TTN, SGO2, NOS3, PDLIM1, CLU, CCS, GPX4, TXNRD2, EPHX2, MTL5, EPX, GPX3, ALOX12, IPCEF1, GSTA, OXR1, GPX6, AOX1, and PRNP. Therefore, a genetic OS background might underlie the complex pathogenesis of DKD in DM2 patients.

Sodium hydrosulfide has no additive effects on nitrite-inhibited renal gluconeogenesis in type 2 diabetic rats

OBJECTIVE

Increased renal and hepatic gluconeogenesis are important sources of fasting hyperglycemia in type 2 diabetes (T2D). The inhibitory effect of co-administration of sodium nitrite and sodium hydrosulfide (NaSH) on hepatic but not renal gluconeogenesis has been reported in rats with T2D. The present study aimed to determine the effects of co-administration of sodium nitrite and NaSH on the expression of genes involved in renal gluconeogenesis in rats with T2D.

METHODS

T2D was induced by a combination of a high-fat diet and low-dose streptozotocin (30 mg/kg). Male Wistar rats were divided into 5 groups (n = 6/group): Control, T2D, T2D + nitrite, T2D + NaSH, and T2D + nitrite+NaSH. Nitrite and NaSH were administered for nine weeks at a dose of 50 mg/L (in drinking water) and 0.28 mg/kg (daily intraperitoneal injection), respectively. Serum levels of urea and creatinine, and mRNA expressions of PEPCK, G6Pase, FBPase, PC, PI3K, AKT, PGC-1α, and FoxO1 in the renal tissue, were measured at the end of the study.

RESULTS

Nitrite decreased mRNA expression of PEPCK by 39%, G6Pase by 43%, FBPase by 41%, PC by 63%, PGC-1α by 45%, and FoxO1 by 27% in the renal tissue of rats with T2D; co-administration of nitrite and NaSH further decreases FoxO1, while had no additive effects on the tissue expression of the other genes. In addition, nitrite+NaSH decreased elevated serum urea levels by 58% and creatinine by 37% in rats with T2D.

CONCLUSION

The inhibitory effect of nitrite on gluconeogenesis in T2D rats is at least in part due to decreased mRNA expressions of renal gluconeogenic genes. Unlike effects on hepatic gluconeogenesis, co-administration of nitrite and NaSH has no additive effects on genes involved in renal gluconeogenesis in rats with T2D.

Fuxin Granules ameliorate diabetic nephropathy in db/db mice through TGF-β1/Smad and VEGF/VEGFR2 signaling pathways

Diabetic nephropathy (DN) is a common disease, and patients often do not have satisfactory treatments. We investigated therapeutic effects of Fuxin Granules(FX) on DN and potential molecular mechanisms. We orally administered doses of FX to db/db mice for 10 weeks and measured total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol. H&E, PAS, Masson, and Oil Red O staining were used to observe the structure of kidneys and calculate indices of kidney function. We used pharmacological analysis to investigate potential mechanisms of FX. Relative mRNA and protein levels in the TGF-β1/Smad, TGF-β1/Smad, and VEGF/VEGFR2 pathways were examined. TC, TG, and LDL-C were markedly reduced, lipid accumulation was low, fibrosis reduced, kidney atrophy improved, kidney lipid droplet number significantly reduced, and glomerular filtration function improved by FX treatment. Multi-channel therapeutic effects in DN through the TGF-β1/Smad and VEGF/VEGFR2 signaling pathways occurred, and FX substantially reduced expression of TGF-β1 in the glomeruli. FX significantly inhibited TGF-β1, Smad2/3 total protein levels, Smad2/3 phosphorylation mRNA levels of TGF-β1, Smad2, and Smad3. eNOS, VEGFA, and VEGFR2 expression was regulated, levels of VEGFA and VEGFR2 were decreased, and FX increased eNOS. FX ameliorated symptoms of DN, resulting in marked improvement in hyperglycemia and hyperlipidemia and optimized structure and function of kidneys in db/db mice. FX efficacy was associated with the TGF-β1/Smad and VEGF/VEGFR2 signaling pathways. We verified this potential mechanism and hope that this study will provide benefits for the clinical treatment of DN.

Unraveling the epigenetic landscape of glomerular cells in kidney disease

Chronic kidney disease (CKD) is a major public health concern and its prevalence and incidence are rising quickly. It is a non-communicable disease primarily caused by diabetes and/or hypertension and is associated with high morbidity and mortality. Despite decades of research efforts, the pathogenesis of CKD remains a puzzle with missing pieces. Understanding the cellular and molecular mechanisms that govern the loss of kidney function is crucial. Abrupt regulation of gene expression in kidney cells is apparent in CKD and shown to be responsible for disease onset and progression. Gene expression regulation extends beyond DNA sequence and involves epigenetic mechanisms including changes in DNA methylation and post-translational modifications of histones, driven by the activity of specific enzymes. Recent advances demonstrate the essential participation of epigenetics in kidney (patho)physiology, as its actions regulate both the integrity of cells but also triggers deleterious signaling pathways. Here, we review the known epigenetic processes regulating the complex filtration unit of the kidney, the glomeruli. The review will elaborate on novel insights into how epigenetics contributes to cell injury in the CKD setting majorly focusing on kidney glomerular cells: the glomerular endothelial cells, the mesangial cells, and the specialized and terminally differentiated podocyte cells.

Anti-hyperglycaemic effects of dioxidovanadium complex cis-[VO2(obz)py] avert kidney dysfunction in streptozotocin-induced diabetic male Sprague-Dawley rats

Despite the success of antidiabetic drugs in alleviation of hyperglycaemia, diabetic complications, including renal dysfunction, continue to be a burden. This raises the need to seek alternative therapies that will alleviate these complications. Accordingly, the aim of this study was to investigate the effects of dioxidovanadium(V) complex cis-[VO₂(obz)py] on renal function in diabetic rats. Streptozotocin-induced diabetic rats were treated with cis-[VO₂(obz)py] (40 mg·kg^-1) twice every third day for five weeks. Diabetic untreated and insulin-treated rats served as the diabetic control and positive control, respectively. Blood glucose concentrations, water intake, urinary output, and mean arterial pressure (MAP) were monitored weekly for five weeks. Rats were then euthanized, and blood and kidney tissues were collected for biochemical analysis. Significant decreases in blood glucose concentrations, MAP, glomerular filtration rate (GFR), and SGLT2 expression, as well as plasma angiotensin and aldosterone concentrations, were observed in the treated groups compared with the diabetic control. The complex also increased urinary glucose concentrations, antioxidant enzymes GPx and SOD concentrations, and decreased MDA concentrations and kidney injury molecule (KIM-1) concentrations. These findings suggest that the anti-hyperglycaemic effects of this vanadium complex may ameliorate kidney dysfunction in diabetes.

Endothelial function and dysfunction: Impact of sodium-glucose cotransporter 2 inhibitors

Diabetes mellitus is associated with endothelial dysfunction that leads to cardiovascular complications. Sodium-glucose cotransporter 2 (SGLT2) inhibitors demonstrated efficacy in glycemic control in type 2 diabetes patients with positive cardiovascular outcome. Recent research revealed a link between SGLT2 inhibition and improved macro- and microvascular endothelial functions. Mechanisms underlying this phenomenon could be due to the role of SLGT2 in the regulation of endothelial physiology. In this review, current knowledge and hypothesis on the link between SGLT2 and endothelial function were critically appraised and the impact of SGLT2 inhibitors on endothelial dysfunction in pre-clinical and clinical studies was discussed.

Effects of the Soluble Guanylate Cyclase Stimulator Praliciguat in Diabetic Kidney Disease: A Randomized Placebo-Controlled Clinical Trial

BACKGROUND AND OBJECTIVES

Impaired nitric oxide signaling through soluble guanylate cyclase has been implicated in the pathophysiology of diabetic kidney disease. Praliciguat, a soluble guanylate cyclase stimulator that amplifies nitric oxide signaling, inhibited kidney inflammation and fibrosis in animal models.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

In a phase 2 trial, 156 adults with type 2 diabetes, eGFR 30-75 ml/min per 1.73 m², and urine albumin-creatinine ratio 200-5000 mg/g treated with renin-angiotensin system inhibitors were randomly allocated 1:1:1 to placebo, 20 mg praliciguat, or 40 mg praliciguat daily for 12 weeks. The primary efficacy and safety outcomes were change from baseline to weeks 8 and 12 in urine albumin-creatinine ratio and treatment-emergent adverse events, respectively. Other outcomes assessed were 24-hour ambulatory BP and metabolic parameters.

RESULTS

Of 156 participants randomized, 140 (90%) completed the study. The primary efficacy analysis demonstrated a mean change from baseline in urine albumin-creatinine ratio of -28% (90% confidence interval, -36 to -18) in the pooled praliciguat group and -15% (-28 to 0.4) in the placebo group (difference -15%; -31 to 4; P=0.17). Between-group decreases from baseline to week 12 for praliciguat versus placebo were seen in mean 24-hour systolic BP (-4 mm Hg; -8 to -1), hemoglobin A1c (-0.3%; -0.5 to -0.03), and serum cholesterol (-10 mg/dl; -19 to -1). The incidence of treatment-emergent adverse events was similar in the pooled praliciguat and placebo groups (42% and 44%, respectively). Serious adverse events, events leading to study drug discontinuation, and events potentially related to BP lowering were reported at higher frequency in the 40-mg group but were similar in 20-mg and placebo groups.

CONCLUSIONS

Praliciguat treatment for 12 weeks did not significantly reduce albuminuria compared with placebo in the primary efficacy analysis. Nonetheless, the observed changes in urine albumin-creatinine ratio, BP, and metabolic variables may support further investigation of praliciguat in diabetic kidney disease.

CLINICAL TRIAL REGISTRY NAME AND REGISTRATION NUMBER

A Study to Evaluate the Soluble Guanylate Cyclase (sGC) Stimulator IW-1973 in Diabetic Nephropathy/Diabetic Kidney Disease as Measured by Albuminuria, NCT03217591.

The Effect of Type of Delivery on the Nitric Oxide Metabolites and Endothelial Dysfunction in Pregnant Women

Background:

Since endothelial dysfunction is related to atherosclerosis, this study was planned to determine the effect of type of delivery on Nitric Oxide (NO) metabolites and endothelial function.

Materials and Methods:

This Cohort study was conducted in 2015 in selected hospitals of Isfahan. 88 nulliparous women with gestational age of 39 weeks and above were enrolled in this study using convenience sampling method and finally, after giving birth, 51 mothers with vaginal delivery, 21 with urgent C-section and 13 with elective C-section were considered for data analysis. The serum levels of NO metabolites were measured in the laboratory with standard kits and data was analyzed using student and paired t-test, one-way ANOVA, and Chi-square test. The significance level was considered less than 0.05 for all tests.

Results:

The NO metabolites levels in mothers who had vaginal delivery or urgent C-section showed a significant difference before and after delivery (normal vaginal delivery (NVD): t₅₀ = 5.61, p < 0.001, Urgent C-section: t₂₃ = 5.38, p < 0.001). But those with elective C-section showed no significant difference in the nitrate and total nitrite levels before and after delivery (p > 0.05).

Conclusions:

Since reduction in serum levels of NO metabolites may possibly indicate endothelial dysfunction and predict cardiovascular disease, especially atherosclerosis in the future, it could be concluded that, childbirth, regardless of the type of delivery, could damage the endothelial cells but C-section (urgent or elective) could cause more disruption than vaginal delivery.

Role of mineralocorticoid receptor antagonists in kidney diseases

Mineralocorticoid receptor (MR) antagonists, for example, spironolactone and eplerenone, are in clinical use to treat hypertension. Increasing evidence suggests that mineralocorticoid receptor activation causes the pathogenesis and progression of chronic kidney disease. Aldosterone-induced MR activation increases inflammation, fibrosis, and oxidative stress in the kidney. MR antagonists (MRAs) have demonstrated therapeutic actions in chronic kidney disease (CKD), diabetic nephropathy (DN), renal fibrosis, and drug-induced renal injury in preclinical and clinical studies. We have summarized and discussed these studies in this review. The nonsteroidal MRA, esaxerenone, recently received approval for the treatment of hypertension. It has also shown a positive therapeutic effect in phase 3 clinical trials in patients with DN. Other nonsteroidal MRA such as apararenone, finerenone, AZD9977, and LY2623091 are in different clinical trials in patients with hypertension suffering from renal or hepatic fibrotic diseases. Hyperkalemia associated with MRA therapy has frequently led to the discontinuation of the treatment. The new generation nonsteroidal MRAs like esaxerenone are less likely to cause hyperkalemia at therapeutic doses. It appears that the nonsteroidal MRAs can provide optimum therapeutic benefit for patients suffering from kidney diseases.

AMPK allostery: A therapeutic target for the management/treatment of diabetic nephropathy

Diabetic nephropathy (DN) is a chronic complication of diabetes mellitus (DM) with approximately 30-40% of patients with DM developing nephropathy, and it is the leading cause of end-stage renal diseases and diabetic morbidity. The pathogenesis of DN is primarily associated with irregularities in the metabolism of glucose and lipid leading to hyperglycemia-induced oxidative stress, which has been a major target together with blood pressure regulation in the control of DN progression. However, the regulation of 5' adenosine monophosphate-activated protein kinase (AMPK), a highly conserved protein kinase for maintaining energy balance and cellular growth and repair has been implicated in the development of DM and its complications. Therefore, targeting AMPK pathway has been explored as a therapeutic strategy for the treatment of diabetes and its complication, although most of the mechanisms have not been fully elucidated. In this review, we discuss the structure of AMPK relevant to understanding its allosteric regulation and its role in the pathogenesis and progression of DN. We also identify therapeutic agents that modulate AMPK and its downstream targets with their specific mechanisms of action in the treatment of DN.

The role of Artemisia turanica extract on renal oxidative and biochemical markers in STZ-induced diabetes in rat

OBJECTIVE

The aim of the current study was to investigate the protective effect of Artemisia turanica (AT) against diabetes- induced renal oxidative stress in rats.

MATERIALS AND METHODS

Fifty male Wistar rats were randomly divided into five groups: control, STZ-induced diabetic rats, diabetic rats+ metformin, diabetic rats + AT extract, diabetic rats+ metformin+ AT extract. In the present study, diabetes was induced by a single-dose (55 mg/kg, ip) injection of streptozotocin (STZ). Diabetic rats were daily treated with metformin (300 mg/kg), AT extract (70 mg/kg) and metformin+ AT extract for 4 consecutive weeks. Tissue activities of superoxide dismutase (SOD) and catalase and the levels of malondialdehyde (MDA) and total thiol content were measured in kidney tissue. Serum concentrations of glucose, creatinine, and urea, as well as, lipid profile were also measured.

RESULTS

STZ significantly increased the levels of glucose, triglyceride, urea and MDA compared to the control group. Total thiol content, as well as, catalase and SOD activities showed significant decreases in diabetic group when compared with the control animals. Serum glucose, triglyceride, cholesterol and renal MDA showed a significant decrease and renal total thiol and the activities of antioxidant enzymes showed significant increases in AT+STZ group compared with the diabetic group. In diabetic rats received AT+ metformin, serum LDL and HDL, renal MDA and SOD and catalase activities significantly improved compared with the diabetic rats.

CONCLUSION

These findings suggested that AT extract has therapeutic effects on renal oxidative damage and lipid profile in diabetes, that possibly may be due to its antioxidant and hypolipidemic effects.

Alk1 haploinsufficiency causes glomerular dysfunction and microalbuminuria in diabetic mice

Endothelial dysfunction has been shown to play an important role in the pathogenesis of glomerular damage during diabetic kidney disease (DKD). As such, a better understanding of the molecular mechanisms involved in glomerular endothelial dysfunctions could provide novel therapeutic strategies for the prevention of DKD. We have previously shown that Alk1/BMP9 signaling plays an important function to maintain vascular integrity in diabetic animals. As such, we evaluated the effects of Alk1 suppression on glomerular endothelial function in diabetic mice. In the present study, we used mice with conditional heterozygote deletion of Alk1 in the endothelium (Alk1ΔEC) to evaluate the role of Alk1 on kidney function during STZ-induced diabetes. DKD was investigated in diabetic control and Alk1ΔEC mice euthanized eight weeks after the onset of diabetes. We showed that Alk1 expression is reduced in the glomeruli of human DKD patients. While renal function was not altered in Alk1ΔEC non-diabetic mice, we showed that Alk1 haploinsufficiency in the glomerular endothelium leads to microalbuminuria, thickening of the glomerular basement membrane, glomerular apoptosis and podocyte loss in diabetic mice. These data suggest that Alk1 is important for the proper function of glomerular endothelial cells and that decreased Alk1 combined with chronic hyperglycemia can impair renal function.

AMPK in microvascular complications of diabetes and the beneficial effects of AMPK activators from plants

BACKGROUND

Diabetes mellitus is a multifactorial disorder with the risk of micro- and macro-vascular complications. High glucose-induced derangements in metabolic pathways are primarily associated with the initiation and progression of secondary complications namely, diabetic nephropathy, neuropathy, and retinopathy. Adenosine monophosphate-activated protein kinase (AMPK) has emerged as an attractive therapeutic target to treat various metabolic disorders including diabetes mellitus. It is a master metabolic regulator that helps in maintaining cellular energy homeostasis by promoting ATP-generating catabolic pathways and inhibiting ATP-consuming anabolic pathways. Numerous pharmacological and plant-derived bioactive compounds that increase AMP-activated protein kinase activation has shown beneficial effects by mitigating secondary complications namely retinopathy, nephropathy, and neuropathy.

PURPOSE

The purpose of this review is to highlight current knowledge on the role of AMPK and its activators from plant origin in diabetic microvascular complications.

METHODS

Search engines such as Google Scholar, PubMed, Science Direct and Web of Science are used to extract papers using relevant key words. Papers mainly focusing on the role of AMPK and AMPK activators from plant origin in diabetic nephropathy, retinopathy, and neuropathy was chosen to be highlighted.

RESULTS

According to results, decrease in AMPK activation during diabetes play a causative role in the pathogenesis of diabetic microvascular complications. Some of the plant-derived bioactive compounds were beneficial in restoring AMPK activity and ameliorating diabetic microvascular complications.

CONCLUSION

AMPK activators from plant origin are beneficial in mitigating diabetic microvascular complications. These pieces of evidence will be helpful in the development of AMPK-centric therapies to mitigate diabetic microvascular complications.