The pathogenesis and management of hypertension in diabetic kidney disease

Hypertension accelerates the development of a diabetic nephropathy model with more relevant clinical features in Dahl salt-sensitive rat

OBJECTIVE

Diabetic nephropathy is becoming an increasing health problem and the major cause of chronic kidney disease. The lack of experimental models that reproduce all structural and functional alterations of human diabetic nephropathy is one of the barriers to solve these clinical needs in basic research. We aimed to establish a simple and rapid method for diabetic nephropathy induction in Dahl salt-sensitive rats and achieved more clinical relevant features.

METHODS AND RESULTS

Six or seven-week-old male Dahl salt-sensitive rats were used to induce diabetes by a single injection of streptozotocin (STZ; 45 mg/kg, intraperitoneally). After 7 days, rats with diabetes (will refer as STZ-DS rats) will be used for further studies. STZ-DS rats will be grouped and were fed with water or water containing 0.3%/0.9%/2% NaCl and a regular chow throughout the study. We found that STZ-treated Dahl salt-sensitive rat fed with 0.9% NaCl in drinking water (STZ-DS + 0.9% NaCl) displayed most of the characteristics of human diabetic nephropathy and the model meets the criteria of the diabetic nephropathy standards proposed by Animal Models of Diabetic Complications Consortium (AMDCC); which includes a 10-fold increase in albuminuria, more than 50% decline in estimated glomerular filtration rate over the lifetime, hypertrophy, thickening of the glomerular basement membrane, expansion of the mesangial matrix, any degree of arteriolar hyalinosis, severe glomerulosclerosis, and tubulointerstitial fibrosis.

CONCLUSION

STZ-DS + 0.9% NaCl is an improved diabetes nephropathy model and more suited for the study of the signaling pathways and mechanisms in the progression of diabetes-induced renal disease. The model will facilitate the development of new therapies for diabetes nephropathy.

Association Between Life's Essential 8 and Diabetic Kidney Disease in Patients With Diabetes Mellitus: Evidence From National Health and Nutrition Examination Survey 2005-2018

BACKGROUND

Diabetic kidney disease (DKD) is often connected with an elevated cardiovascular disease risk. A novel index, the Life's Essential 8 (LE8), was developed with the American Heart Association to ascertain cardiovascular health. In people with diabetes mellitus, we aimed to estimate if LE8 possessed a connection with DKD risk.

METHODS

We implemented data from the National Health and Nutrition Examination Survey from 2005 to 2018. The correlation between LE8 and DKD was evaluated with weighted multivariate logistic regression models and restricted cubic spline models with covariate adjustments. In addition, we performed subgroup analyses and interaction tests.

RESULTS

After taking into account relevant confounding factors, the findings indicated that higher levels of LE8 was linked to a decreased probability of developing DKD (per 10-point increase in LE8, OR = 0.75, 95%CI = 0.68-0.84, P < .001). The subscales of the LE8 similarly demonstrated negative associations with DKD risk. After grouping the LE8 scores, it was found that individuals with high LE8 were significantly less likely to develop DKD compared to those with low LE8 (OR = 0.32, 95%CI = 0.15-0.70, P = .005). The association between LE8 and DKD was consistent across different subgroups.

CONCLUSION

LE8 scores were shown to have a significantly negative association with the risk of DKD in people with diabetes mellitus. By concentrating on the state of cardiovascular health, it may be possible to lessen the impact of DKD.

Factors associated with chronic kidney disease in patients with diabetes in French Guiana

Introduction

With over half of the population living under the poverty threshold, the social and health context in French Guiana is more difficult than in mainland France. The prevalence of diabetes is twice as great and end-stage renal failure is 45% higher than in mainland France.

Objective

Our objective was to describe the profile of diabetic patients with chronic kidney disease in French Guiana and search for possible risk factors.

Method

We conducted a multicenter cross-sectional observational study based on the CODIAM cohort (Cohort of Diabetes in French Amazonia). We analyzed 1,287 patients followed up between May 2019 and June 2021 at Cayenne Hospital, Saint Laurent Hospital, and delocalized health centers.

Results

In our cohort, chronic kidney disease was present after an average of 12 years of diabetes. Compared with the French population, 41% of diabetic patients had chronic kidney disease (i.e., 12% more), and had an average age of 56 years (i.e., 10 years younger). Forty-eight per cent of these patients were obese (i.e., 7% more). Seventy-four per cent of patients were precarious and 45% were foreigners but neither was associated with chronic kidney disease, contrary to countries where the health system is not universal.

Conclusion

Screening of patients with chronic kidney disease among diabetics in French Guiana remains a real challenge. Patients were younger and more obese than in other French territories. In this cohort, precariousness and immigration were not associated with the presence of chronic kidney disease. However, particular attention should be paid to hypertensive patients and those over 65 years of age, which are, with diabetes itself, the two most obvious risk factors for developing chronic kidney disease among diabetic patients in our territory.

Therapeutic effects of lisinopril and empagliflozin in a mouse model of hypertension-accelerated diabetic kidney disease

Hypertension is a critical comorbidity for progression of diabetic kidney disease (DKD). To facilitate the development of novel therapeutic interventions with the potential to control disease progression, there is a need to establish translational animal models that predict treatment effects in human DKD. The present study aimed to characterize renal disease and outcomes of standard of medical care in a model of advanced DKD facilitated by adeno-associated virus (AAV)-mediated renin overexpression in uninephrectomized (UNx) db/db mice. Five weeks after single AAV administration and 4 wk after UNx, female db/db UNx-ReninAAV mice received (PO, QD) vehicle, lisinopril (40 mg/kg), empagliflozin (20 mg/kg), or combination treatment for 12 wk (n = 17 mice/group). Untreated db/+ mice (n = 8) and vehicle-dosed db/db UNx-LacZAAV mice (n = 17) served as controls. End points included plasma, urine, and histomorphometric markers of kidney disease. Total glomerular numbers and individual glomerular volume were evaluated by whole kidney three-dimensional imaging analysis. db/db UNx-ReninAAV mice developed hallmarks of progressive DKD characterized by severe albuminuria, advanced glomerulosclerosis, and glomerular hypertrophy. Lisinopril significantly improved albuminuria, glomerulosclerosis, tubulointerstitial injury, and inflammation. Although empagliflozin alone had no therapeutic effect on renal endpoints, lisinopril and empagliflozin exerted synergistic effects on renal histological outcomes. In conclusion, the db/db UNx-ReninAAV mouse demonstrates good clinical translatability with respect to physiological and histological hallmarks of progressive DKD. The efficacy of standard of care to control hypertension and hyperglycemia provides a proof of concept for testing novel drug therapies in the model.NEW & NOTEWORTHY Translational animal models of diabetic kidney disease (DKD) are important tools in preclinical research and drug discovery. Here, we show that the standard of care to control hypertension (lisinopril) and hyperglycemia (empagliflozin) improves physiological and histopathological hallmarks of kidney disease in a mouse model of hypertension-accelerated progressive DKD. The findings substantiate hypertension and type 2 diabetes as essential factors in driving DKD progression and provide a proof of concept for probing novel drugs for potential nephroprotective efficacy in this model.

The 100 top-cited articles in diabetic kidney disease: a bibliometric analysis

Background

Tremendous scientific researches have been conducted in the field of diabetic kidney disease (DKD), while few bibliometric analyses have been performed. We aim to identify 100 top-cited published articles about DKD and analyze their main characteristics quantitatively.

Methods

Web of Science was searched with the term ‘diabetic kidney disease’ OR ‘diabetic nephropathy’ to identify the top 100 most cited articles. For articles meeting the predefined criteria, the following data were extracted and analyzed: citation ranking, publication year, publication journal, journal impact factor, country and institution, authors, study type, and keywords.

Results

The highest number of citations was 4753 times. The median average citations per year was 21.8 (IQR, 16.6–33.0). Most articles focused on the pathogenesis and treatment. These articles were published in 25 different journals and the Journal of the American Society of Nephrology published the greatest number (20%). Forty-three articles (43%) originated from the United States. The University of Groningen was the leading institute, contributing five top-cited articles. The most frequent first author was de Zeeuw (n = 4), followed by Parving (n = 3). There was no correlation between the average citations and the number of authors, the number of institutes, or the number of funds, respectively. Experimental animal study was the research type most frequently conducted (n = 30), followed by observational study (n = 24). Keyword analysis revealed transforming growth factor-β, oxidative stress, proteinuria, and renin–angiotensin–aldosterone system interruption are classic research topics. Sodium-glucose cotransporter 2 inhibitors, glucagon-like peptide 1 receptor agonists, and anti-inflammatory agents are the emerging trends of DKD.

Conclusions

This bibliometric analysis helps in identifying the milestones, inadequacies, classic hotspots, and emerging trends of DKD. Pathogenesis and treatment are core themes in DKD research, while high-quality articles on the prediction and biomarker are insufficient. New analyzing metrics are needed to assess the actual impact of these top-cited articles on clinical practice.

Costs of Managing Patients with Diabetes in a Large Health Maintenance Organization in Israel: A Retrospective Cohort Study

INTRODUCTION

The aim of this study was to evaluate the direct costs of patients with diabetes ensured in a large health maintenance organization, Maccabi Health Services (MHS), in order to compare the medical costs of these patients to the medical costs of other patients insured by MHS and to assess the impact of poorly controlled diabetes on medical costs.

METHODS

A retrospective analysis of patients insured in MHS during 2012 was performed. Data were extracted automatically from the electronic database. A glycated hemoglobin (HbA1c) level of >9% (75 mmol/mol) was considered to define poorly controlled diabetes, and that of <7% (53 mmol/mol) and <8% (64 mmol/mol) to define controlled diabetes for patients aged <75 and ≥75 years, respectively. Multivariate analysis analyses were done to assess factors affecting cost.

RESULTS

Data on a total of 99,017 patients with diabetes were obtained from the MHS database for 2012. Of these, 54% were male and 72% were aged 45-75 years. The median annual cost of treating diabetes was 4420 cost units (CU), with hospitalization accounting for 56% of the total costs. The median annual cost per patient in the age groups 35-44 and 75-84 years was 2836 CU and 7033 CU, respectively. Differences between costs for patients with diabetes and those for patients without diabetes was 85% for the age group 45-54 years but only 24% for the age group 75-84 years. Medical costs increased similarly with age for patients with controlled diabetes and those with poorly controlled diabetes costs, as did additional co-morbidities. Costs were significantly impacted by kidney disease. The costs for patients with an HbA1c level of 8.0-8.99% (64-74 mmol/mol) and 9.0-9.99% (75-85 mmol/mol) were 5722 and 5700 CU, respectively. In a multivariate analysis the factors affecting all patients' costs were HbA1C level, male gender, chronic diseases, complications of diabetes, disease duration, and stage of kidney function.

CONCLUSIONS

The direct medical costs of patients with diabetes were significantly higher than those of patients without diabetes. The main drivers of these higher costs were hospitalizations and renal function. In poorly controlled patients the effect of HbA1c on costs was limited. These findings suggest that it is cost effective to identify patients with diabetes early in the course of the disease.

FUNDING

The work was sponsored by internal funds of the authors. Article processing charges for this study was funded by Novo Nordisk.

Management of anemia in patients with diabetic kidney disease: A consensus statement

This consensus statement focuses on the window of opportunity, which exists while treating patients with diabetic kidney disease and anemia.

Routine kidney variables, glomerular filtration rate and urinary cystatin C in cats with diabetes mellitus, cats with chronic kidney disease and healthy cats

OBJECTIVES

Diabetic kidney disease (DKD) is a frequent and serious complication in human diabetic patients, but data are limited in cats. This study was undertaken to assess whether diabetic cats are susceptible to DKD.

METHODS

Kidney function was compared between 36 cats with diabetes mellitus (DM), 10 cats with chronic kidney disease (CKD) and 10 age-matched healthy cats by measuring routine kidney variables (serum creatinine [sCreat], serum urea [sUrea], urine specific gravity [USG], urinary protein:creatinine ratio [UPC]), urinary cystatin C:creatinine ratio and glomerular filtration rate (GFR). Urinary cystatin C (uCysC) was measured with a human particle-enhanced nephelometric immunoassay, validated to measure feline cystatin C, in all but two diabetic cats. GFR was evaluated by exo-iohexol clearance in 17 diabetic cats, all cats with CKD and all healthy cats.

RESULTS

Diabetic cats had significantly (mean ± SD) lower sCreat (123 ± 38 vs 243 ± 80 µmol/l), sUrea (11 ± 3 vs 18 ± 7 mmol/l) and urinary cystatin C:creatinine ratio (6 ± 31 vs 173 ± 242 mg/mol), and a significantly higher USG (1.033 ± 0.012 vs 1.018 ± 0.006) and GFR (2.0 ± 0.7 vs 0.8 ± 0.3 ml/min/kg) compared with cats with CKD. Compared with healthy cats, diabetic cats only had significantly lower USG (1.033 ± 0.012 vs 1.046 ± 0.008). Proteinuria (UPC >0.4) was present in 39% of diabetic cats, in 30% of cats with CKD and in none of the healthy cats. However, the UPC did not differ statistically between the three groups.

CONCLUSIONS AND RELEVANCE

Based on evaluation of routine kidney variables, GFR and uCysC as a tubular marker at a single time point, a major impact of feline DM on kidney function could not be demonstrated.

Diabetic kidney disease

The kidney is arguably the most important target of microvascular damage in diabetes. A substantial proportion of individuals with diabetes will develop kidney disease owing to their disease and/or other co-morbidity, including hypertension and ageing-related nephron loss. The presence and severity of chronic kidney disease (CKD) identify individuals who are at increased risk of adverse health outcomes and premature mortality. Consequently, preventing and managing CKD in patients with diabetes is now a key aim of their overall management. Intensive management of patients with diabetes includes controlling blood glucose levels and blood pressure as well as blockade of the renin-angiotensin-aldosterone system; these approaches will reduce the incidence of diabetic kidney disease and slow its progression. Indeed, the major decline in the incidence of diabetic kidney disease (DKD) over the past 30 years and improved patient prognosis are largely attributable to improved diabetes care. However, there remains an unmet need for innovative treatment strategies to prevent, arrest, treat and reverse DKD. In this Primer, we summarize what is now known about the molecular pathogenesis of CKD in patients with diabetes and the key pathways and targets implicated in its progression. In addition, we discuss the current evidence for the prevention and management of DKD as well as the many controversies. Finally, we explore the opportunities to develop new interventions through urgently needed investment in dedicated and focused research. For an illustrated summary of this Primer, visit: http://go.nature.com/NKHDzg.

Sex-dependent differences in renal angiotensinogen as an early marker of diabetic nephropathy

AIM

The renal renin-angiotensin system (RAS) has been implicated in the pathogenesis of diabetic nephropathy. The aim of this study was to investigate sex differences in renal renin-angiotensin system (RAS) and the roles of androgens in diabetes-associated renal injury.

METHODS

Renal injury and fibrosis were studied in streptozotocin-induced diabetic rats by albuminuria and by gene expression of collagen I and fibronectin. RAS was investigated by analysing the plasma angiotensinogen (AOGEN) and renin activity (PRA) and their renal gene expression. Also, a group of diabetic rats was treated with the anti-androgen flutamide.

RESULTS

Albuminuria was significantly lower in diabetic females than in males (1.2 [0.8-1.5] versus 4.4 [2.2-6.1] mg/24 h, data are median [IQR] values, P < 0.05). Renal AOGEN mRNA levels were increased by diabetes in males (8.1 ± 0.8% in diabetes versus 0.8 ± 0.2% in control, P < 0.001) but not in females (1.0 ± 0.1% in diabetes versus 0.8 ± 0.1% in control, P > 0.05), as were collagen I and fibronectin mRNAs. Furthermore, AOGEN mRNA levels were strongly correlated with albuminuria (Spearman r = 0.64, 95% [CI] 0.36-0.81, P < 0.0001). Diabetes decreased PRA, renal renin mRNA and plasma AOGEN in both females and males. Anti-androgen treatment decreased albuminuria only in diabetic males without affecting the endocrine or renal RAS.

CONCLUSIONS

These data indicate that renal but not hepatic AOGEN or renin is positively associated with diabetic albuminuria and contribute to the sex-dependent differences in renal injury. Androgens may contribute to albuminuria in male independently of the RAS.

Hypertension is a major contributor to 20-hydroxyeicosatetraenoic acid-mediated kidney injury in diabetic nephropathy

In the kidney, 20-hydroxyeicosatetraenoic acid (20-HETE) is a primary cytochrome P450 4 (Cyp4)-derived eicosanoid that enhances vasoconstriction of renal vessels and induces hypertension, renal tubular cell hypertrophy, and podocyte apoptosis. Hypertension and podocyte injury contribute to diabetic nephropathy and are strong predictors of disease progression. In this study, we defined the mechanisms whereby 20-HETE affects the progression of diabetic nephropathy. We used Cyp4a14KO male mice that exhibit androgen-sensitive hypertension due to increased Cyp4a12-mediated 20-HETE production. We show that, upon induction of diabetes type 1 via streptozotocin injection, Cyp4a14KO male mice developed worse renal disease than streptozotocin-treated wild-type mice, characterized by increased albuminuria, mesangial expansion, glomerular matrix deposition, and thickness of the glomerular basement membranes. Castration blunted androgen-mediated Cyp4a12 synthesis and 20-HETE production, normalized BP, and ameliorated renal damage in diabetic Cyp4a14KO mice. Notably, treatment with a 20-HETE antagonist or agents that normalized BP without affecting Cyp4a12 expression and 20-HETE biosynthesis also ameliorated diabetes-mediated renal damage and albuminuria in Cyp4a14KO male mice. Taken together, these results suggest that hypertension is the major contributor to 20-HETE-driven diabetes-mediated kidney injury.

Validation of the Comprehensive International Classification of Functioning, Disability and Health (ICF) Core Set for Diabetes Mellitus in patients with diabetic nephropathy

BACKGROUND

Diabetic nephropathy (DMN) is the most common cause of end-stage renal disease. Progression of DMN leads to impairment of physical activity, restriction of daily activities, and diminished social participation. Therefore, the precise assessment of the physical and psychosocial problems of DMN patients is important. The objective of this study was to validate the Comprehensive International Classification of Functioning, Disability and Health Core Set for Diabetes Mellitus (ICF-CS for DM) from the perspective of DMN patients.

METHODS

A total of 176 DMN outpatients were interviewed using the ICF-CS for DM. Content and construct validity were evaluated. Patients were divided into 2 groups: DMN patients without hemodialysis (HD) (non-HD group) and DMN patients undergoing HD (HD group). Content validity was evaluated based on the frequency of patients who had a problem in each category. For construct validity, the patients were divided into two groups based on DM duration and hemoglobin A1C levels.

RESULTS

Content validity evaluation revealed 58 categories reported as problem categories: 39 categories in the non-HD group and 50 categories in the HD group. Construct validity evaluation showed that longer DM duration and poor glycemic control contributes to increased problems.

CONCLUSIONS

Content and construct validity of the ICF-CS for DM was supported from the DMN patients' perspective. Some categories of the "Environmental factors" component need further studies to be appropriate.

The impact of blood pressure on kidney function in the elderly: a cross-sectional study

BACKGROUND/AIMS

Intensive blood pressure (BP) target decreases blood perfusion of kidneys that attenuates the benefits of BP treatment in elderly hypertensive individuals. The optimal BP goal for renal function in the hypertensive elderly has been unclear. We investigated the impact of BP on renal function to define the appropriate BP target in the elderly.

METHODS

A total of 28,258 elderly subjects were categorized into normotensive (Norm), hypotensive (Hypo) and hypertensive (Hyper) groups according to BP levels. Systolic, diastolic and pulse BP (SBP, DBP and PBP) were further stratified by 10 mmHg. Blood urea nitrogen, serum creatinine, uric acid, glomerular filtration rate (GFR), renal insufficiency prevalence (RIP) and proteinuria prevalence (PP) were compared among different groups and BP strata. The RIP and PP in the elderly with obesity, hyperlipidemia or diabetes in Norm, Hypo and Hyper groups were evaluated.

RESULTS

GFR in Hypo and Hyper groups was significantly lower than that in Norm group. The RIP and PP was higher in Hypo and Hyper groups than that in the Norm group. Proteinuria became more prevalent when SBP was >140 mmHg or <90 mmHg. DBP>80 mmHg increased PP while DBP<70 mmHg increased RIP. PBP>60 mmHg led to an increased RIP and PP. Obesity or hyperlipidemia only combined with hypertension caused a significantly increased RIP and PP. Diabetes independent of hypertension contributed to higher RIP and PP.

CONCLUSIONS

The most beneficial BP target for kidney function in the elderly may be SBP of 90-140 mmHg and DBP of 70-80 mmHg. PBP <60 mmHg may be appropriate.

Omega-3 fatty acids protect renal functions by increasing docosahexaenoic acid-derived metabolite levels in SHR.Cg-Lepr(cp)/NDmcr rats, a metabolic syndrome model

The omega-3 polyunsaturated fatty acids (ω-3 PUFAs) docosahexaenoic acid (DHA) and/or eicosapentaenoic acid (EPA) protect against diabetic nephropathy by inhibiting inflammation. The aim of this study was to assess the effects of highly purified DHA and EPA or EPA only administration on renal function and renal eicosanoid and docosanoid levels in an animal model of metabolic syndrome, SHR.Cg-Lepr^cp/NDmcr (SHRcp) rats. Male SHRcp rats were divided into 3 groups. Control (5% arabic gum), TAK-085 (300 mg/kg/day, containing 467 mg/g EPA and 365 mg/g DHA), or EPA (300 mg/kg/day) was orally administered for 20 weeks. The urinary albumin to creatinine ratio in the TAK-085-administered group was significantly lower than that in other groups. The glomerular sclerosis score in the TAK-085-administered group was significantly lower than that in the other groups. Although DHA levels were increased in total kidney fatty acids, the levels of nonesterified DHA were not significantly different among the 3 groups, whereas the levels of protectin D1, resolvin D1, and resolvin D2 were significantly increased in the TAK-085-administered group. The results show that the use of combination therapy with DHA and EPA in SHRcp rats improved or prevented renal failure associate with metabolic syndrome with decreasing triglyceride levels and increasing ω-3 PUFA lipid mediators.