Cardiovascular risk in diabetic end-stage renal disease patients

Comparison of SGLT1, SGLT2, and Dual Inhibitor biological activity in treating Type 2 Diabetes Mellitus

Diabetes Mellitus Type 2 (T2D) is an emerging health burden in the USand worldwide, impacting approximately 15% of Americans. Current front-line therapeutics for T2D patients include sulfonylureas that act to reduce A1C and/or fasting blood glucose levels, or Metformin that antagonizes the action of glucagon to reduce hepatic glucose production. Next generation glucomodulatory therapeutics target members of the high-affinity glucose transporter Sodium-Glucose-Linked-Transporter (SGLT) family. SGLT1 is primarily expressed in intestinal epithelium, whose inhibition reduces dietary glucose uptake, whilst SGLT2 is highly expressed in kidney - regulating glucose reabsorption. A number of SGLT2 inhibitors are FDA approved whilst SGLT1 and dual SGLT1 & 2 inhibitor are currently in clinical trials. Here, we discuss and compare SGLT2, SGLT1, and dual inhibitors' biochemical mechanism and physiological effects.

Higher Fasting Pretransplant C-peptide Levels in Type 2 Diabetics Undergoing Simultaneous Pancreas-kidney Transplantation Are Associated With Posttransplant Pancreatic Graft Dysfunction

BACKGROUND

Among selected patients with type 2 diabetes mellitus (T2DM), simultaneous pancreas and kidney (SPK) transplants can be an effective option. However, data are limited about outcomes in T2DM SPK recipients based on the pretransplant C-peptide levels.

METHODS

In this study, we reviewed all T2DM SPK recipients and categorized them based on the pretransplant fasting C-peptide levels into 3 groups: low (≤2 ng/mL), medium (>2-8 ng/mL), and high (>8 ng/mL). Several measures of graft failures (GFs), graft dysfunction, and composite outcomes were of interest.

RESULTS

There were a total of 76 SPK recipients (low, n = 14; medium, n = 47; high, n = 15). At the last follow-up, the low group did not reach any outcome; in contrast, 11 (23%) in the medium group and 5 (33%) in the high group reached the uncensored composite outcome; 6 (13%) in the medium group and 2 (13%) in the high group had GF; and 8 (17%) in the medium group and 4 (26.7%) in the high group reached the death-censored composite outcomes. In a fully adjusted model, each pretransplant C-peptide unit was not associated with an increased risk of the composite outcome, GF, or death-censored composite outcomes. However, in multivariate analysis with limited adjustment, pretransplant C-peptide was associated with the composite outcome (hazard ratio: 1.18, 95% confidence interval, 1.01-1.38; P = 0.03) and death-censored composite outcome (hazard ratio: 1.20; 95% confidence interval, 1.01-1.42; P = 0.03).

CONCLUSIONS

Although limited by the small sample size, we found excellent outcomes among T2DM SPK recipients overall. However, higher levels of pretransplant C-peptide may be associated with inferior posttransplant outcomes that include graft dysfunction.

Continuous Glucose Monitoring to Optimize Management of Diabetes in Patients with Advanced CKD

Treatment of patients with diabetes and CKD includes optimizing glycemic control using lifestyle modifications and drugs that safely control glycemia and improve clinical kidney and cardiovascular disease outcomes. However, patients with advanced CKD, defined as eGFR <30 ml/min per 1.73 m2 or kidney disease treated with dialysis, have limitations to the use of some preferred glucose-lowering medications, are often treated with insulin, and experience high rates of severe hypoglycemia. Moreover, hemoglobin A1c accuracy decreases as GFR deteriorates. Hence, there is a need for better glycemic monitoring tools. Continuous glucose monitoring allows for 24-hour glycemic monitoring to understand patterns and the effects of lifestyle and medications. Real-time continuous glucose monitoring can be used to guide the administration of insulin and noninsulin therapies. Continuous glucose monitoring can overcome the limitations of self-monitored capillary glucose testing and hemoglobin A1c and has been shown to prevent hypoglycemic excursions in some populations. More data are needed to understand whether similar benefits can be obtained for patients with diabetes and advanced CKD. This review provides an updated approach to management of glycemia in advanced CKD, focusing on the role of continuous glucose monitoring in this high-risk population.

Arterial Stiffness as a Cardiovascular Risk Factor After Successful Kidney Transplantation in Diabetic and Nondiabetic Patients

BACKGROUND

It is known that kidney transplantation (KTx) decreases mortality rate and increases life expectancy about 10 years compared with dialysis, particularly in patients with diabetes. However, cardiovascular disease is still the most common cause of death after transplantation.

PURPOSE

The evaluation of the cardiovascular risk after successful KTx in diabetic and nondiabetic patients.

METHODS

We enrolled 344 patients after KTx (mean age 52.7 years, M -62.5%). The cohort was divided into 2 groups diabetes (+) and diabetes (-). Arterial stiffness parameters (brachial-ankle and carotid-femoral pulse wave velocity, pulse pressure, pulsatile stress was assessed by an automated oscillometric device. All body composition parameters were evaluated based on bioelectrical impedance analysis and laboratory parameters were obtained from medical files of the patients.

RESULTS

Arterial stiffness parameters were higher in the diabetes (+) compared with diabetes (-) group, significantly. Body mass index was significantly higher in the diabetes (+) group, as well as body fat mass and visceral fat area. In the diabetes (+) group compared with the diabetes (-) group, whole-body phase angle was lower (4.54 vs 4.90 P = .006). Visceral fat area and whole-body phase angle correlated significantly with arterial stiffness parameters.

CONCLUSIONS

The evaluation of arterial stiffness and phase angle is a useful method for identifying patients at high cardiovascular risk. Therefore, we suggest that patients with diabetes after successful KTx due to the baseline high cardiolovascular risk, should be regularly assessed to monitor changes in blood vessels, body composition and undergo dietary intervention.

Inflammation Drives Stiffness Mediated Uptake of Lipoproteins in Primary Human Macrophages and Foam Cell Proliferation

Macrophage to foam cell transition and their accumulation in the arterial intima are the key events that trigger atherosclerosis, a multifactorial inflammatory disease. Previous studies have linked arterial stiffness and cardiovascular disease and have highlighted the use of arterial stiffness as a potential early-stage marker. Yet the relationship between arterial stiffness and atherosclerosis in terms of macrophage function is poorly understood. Thus, it is pertinent to understand the mechanobiology of macrophages to clarify their role in plaque advancement. We explore how substrate stiffness affects proliferation of macrophages and foam cells, traction forces exerted by macrophages and uptake of native and oxidized low-density lipoproteins. We demonstrate that stiffness influences foam cell proliferation under both naïve and inflammatory conditions. Naïve foam cells proliferated faster on the 4 kPa polyacrylamide gel and glass whereas under inflammatory conditions, maximum proliferation was recorded on glass. Macrophage and foam cell traction forces were positively correlated to the substrate stiffness. Furthermore, the influence of stiffness was demonstrated on the uptake of lipoproteins on macrophages treated with lipopolysaccharide + interferon gamma. Cells on softer 1 kPa substrates had a significantly higher uptake of low-density lipoproteins and oxidized low-density lipoproteins compared to stiffer substrates. The results herein indicate that macrophage function is modulated by stiffness and help better understand ways in which macrophages and foam cells could contribute to the development and progression of atherosclerotic plaque.

Serum Carnosinase-1 and Albuminuria Rather than the CNDP1 Genotype Correlate with Urinary Carnosinase-1 in Diabetic and Nondiabetic Patients with Chronic Kidney Disease

BACKGROUND

Carnosinase-1 (CN-1) can be detected in 24 h urine of healthy individuals and patients with type 2 diabetes (T2DM). We aimed to assess whether urinary CN-1 is also reliably measured in spot urine and investigated its association with renal function and the albumin/creatinine ratio (ACR). We also assessed associations between the CNDP1 (CTG) _n genotype and CN-1 concentrations in serum and urine.

METHODS

Patients with T2DM (n = 85) and nondiabetic patients with chronic kidney disease (CKD) (n = 26) stratified by albuminuria (ACR ≤ 300 mg/g or ACR > 300 mg/g) recruited from the nephrology clinic and healthy subjects (n = 24) were studied.

RESULTS

Urinary CN-1 was more frequently detected and displayed higher concentrations in patients with ACR > 300 mg/g as compared to those with ACR ≤ 300 mg/g irrespective of the baseline disease (T2DM: 554 ng/ml [IQR 212-934 ng/ml] vs. 31 ng/ml [IQR 31-63 ng/ml] (p < 0.0001) and nondiabetic CKD: 197 ng/ml [IQR 112-739] vs. 31 ng/ml [IQR 31-226 ng/ml] (p = 0.015)). A positive correlation between urinary CN-1 and ACR was found (r = 0.68, p < 0.0001). Multivariate linear regression analysis revealed that ACR and serum CN-1 concentrations but not eGFR or the CNDP1 genotype are independent predictors of urinary CN-1, explaining 47% of variation of urinary CN-1 concentrations (R ² = 0.47, p < 0.0001).

CONCLUSION

These results confirm and extend previous findings on urinary CN-1 concentrations, suggesting that assessment of CN-1 in spot urine is as reliable as in 24 h urine and may indicate that urinary CN-1 in macroalbuminuric patients is primarily serum-derived and not locally produced.

Vitamin D3 ameliorates podocyte injury through the nephrin signalling pathway

Renal podocytes form the main filtration barrier possessing unique phenotype maintained by proteins including podocalyxin and nephrin, which are modulated in pathological conditions. In diabetic nephropathy (DN), podocytes become structurally and functionally compromised. Nephrin, a structural backbone protein of the slit diaphragm, acts as regulator of podocyte intracellular signalling with renoprotective role. Vitamin D₃ through its receptor, VDR, provides renal protection in DN but limited data exist about its effect on podocytes. In this study, we used isolated rat glomeruli to assess podocalyxin and nephrin expression after treatment with the 1,25‐dihydroxyvitamin D₃ analogue paricalcitol in the presence of normal and diabetic glucose levels. The role of 1,25‐dihydroxyvitamin D₃ (calcitriol) and its analogue, paricalcitol, on podocyte morphology and survival was also investigated in the streptozotocin (STZ)‐diabetic animal model. In our ex vivo model, glomeruli exhibited high glucose‐mediated down‐regulation of podocalyxin, and nephrin, while paricalcitol reversed the high glucose‐induced decrease of nephrin and podocalyxin expression. Paricalcitol treatment enhanced VDR expression and promoted VDR and RXR co‐localization in the nucleus. Our data also indicated that hyperglycaemia impaired survival of cultured glomeruli and suggested that the implemented nephrin down‐regulation was reversed by paricalcitol treatment, initiating Akt signal transduction which may be involved in glomerular survival. Our findings were further verified in vivo, as in the STZ‐diabetic animal model, calcitriol and paricalcitol treatment resulted in significant amelioration of hyperglycaemia and restoration of nephrin signalling, suggesting that calcitriol and paricalcitol may provide molecular bases for protection against loss of the permselective renal barrier in DN.

RAGE-Aptamer Blocks the Development and Progression of Experimental Diabetic Nephropathy

The interaction of advanced glycation end products (AGEs) and their receptor (RAGE) plays a central role in diabetic nephropathy. We screened DNA aptamers directed against RAGE (RAGE-aptamers) in vitro and examined the effects on the development and progression of diabetic nephropathy in streptozotocin-induced diabetic rats. RAGE-aptamer bound to RAGE with a K_d of 5.68 nmol/L and resultantly blocked the binding of AGEs to RAGE. When diabetic rats received continuous intraperitoneal injection of RAGE-aptamer from week 7 to 11 of diabetes, the increases in renal NADPH oxidase activity, oxidative stress generation, AGE, RAGE, inflammatory and fibrotic gene and protein levels, macrophage and extracellular matrix accumulation, and albuminuria were significantly suppressed, which were associated with improvement of podocyte damage. Two-week infusion of RAGE-aptamer just after the induction of diabetes also inhibited the AGE-RAGE-oxidative stress system and MCP-1 levels in the kidneys of 8-week-old diabetic rats and simultaneously ameliorated podocyte injury and albuminuria. Moreover, RAGE-aptamer significantly suppressed the AGE-induced oxidative stress generation and inflammatory and fibrotic reactions in human cultured mesangial cells. The findings suggest that continuous infusion of RAGE-aptamer could attenuate the development and progression of experimental diabetic nephropathy by blocking the AGE-RAGE axis.

The Impact of Diabetes Mellitus on Vascular Biomarkers in Patients with End-Stage Renal Disease

PURPOSE

Diabetes mellitus (DM) is the most common cause of end-stage renal disease (ESRD) and an important risk factor for cardiovascular (CV) disease. We investigated the impact of DM on subclinical CV damage by comprehensive screening protocol in ESRD patients.

MATERIALS AND METHODS

Echocardiography, coronary computed tomography angiogram, 24-h ambulatory blood pressure monitoring, and central blood pressure with pulse wave velocity (PWV) were performed in 91 ESRD patients from the Cardiovascular and Metabolic disease Etiology Research Center-HIgh risk cohort.

RESULTS

The DM group (n=38) had higher systolic blood pressure than the non-DM group (n=53), however, other clinical CV risk factors were not different between two groups. Central aortic systolic pressure (148.7±29.8 mm Hg vs. 133.7±27.0 mm Hg, p= 0.014), PWV (12.1±2.7 m/s vs. 9.4±2.1 m/s, p<0.001), and early mitral inflow to early mitral annulus velocity (16.7±6.4 vs. 13.7±5.9, p=0.026) were higher in the DM group. Although the prevalence of coronary artery disease (CAD) was not different between the DM and the non-DM group (95% vs. 84.4%, p=0.471), the severity of CAD was higher in the DM group (p=0.01). In multivariate regression analysis, DM was an independent determinant for central systolic pressure (p=0.011), PWV (p<0.001) and the prevalence of CAD (p=0.046).

CONCLUSION

Diabetic ESRD patients have higher central systolic pressure and more advanced arteriosclerosis than the non-DM control group. These findings suggest that screening for subclinical CV damage may be helpful for diabetic ESRD patients.

Renal Outcomes of Pioglitazone Compared with Acarbose in Diabetic Patients: A Randomized Controlled Study

Objective

To assess the effect of pioglitazone on renal outcome, including urinary albumin excretion and estimated glomerular filtration rate (eGFR), in diabetic patients.

Design

A prospective, randomized, open-labeled, controlled study.

Setting

Taipei Veterans General Hospital.

Patients

Sixty type 2 diabetic patients treated with sulfonylureas and metformin, whose glycated hemoglobin (HbA1c) levels were between 7% and 10% and eGFR was between 45 and 125 mL/min/1.73 m².

Intervention

The patients were randomized to receive acarbose or pioglitazone and followed up for 6 months. Thirty patients were randomly assigned to receive acarbose, and 30 patients were assigned to receive pioglitazone.

Measurements

The primary study endpoint was the changes in the urinary albumin-to-creatinine ratio (UACR). The secondary endpoint was the changes in eGFR and other parameters.

Results

After 6 months of treatment, the mean changes in UACR were −18 ± 104 and 12 ± 85 (p = 0.25, between groups) for the acarbose and pioglitazone groups, respectively. The mean changes in eGFR were 0 ± 14 and −7 ± 16 mL/min/1.73 m² (p = 0.09, between groups) for the acarbose and pioglitazone groups, respectively. The reductions in HbA1c were similar in both groups. Fasting blood glucose was lower in the pioglitazone group than in the acarbose group. Significant body weight gain was observed in the pioglitazone group as compared with the acarbose group (1.3 ± 2.8 vs. −0.6 ± 1.5 kg, p = 0.002).

Conclusion

In type 2 diabetic patients who were treated with sulfonylureas and metformin and possessed HbA1c levels between 7% and 10%, additional acarbose or pioglitazone for 6 months provided similar glycemic control and eGFR and UACR changes. In the pioglitazone group, the patients exhibited significant body weight gain.

Trial Registration

ClinicalTrials.gov NCT01175486

The Incidence of End-Stage Renal Disease in the Diabetic (Compared to the Non-Diabetic) Population: A Systematic Review

End-stage renal disease (ESRD) in diabetes is a life threatening complication resulting in a poor prognosis for patients as well as high medical costs. The aims of this systematic review were (1) to evaluate the incidence of ESRD due to all causes and due to diabetic nephropathy in the diabetic population and differences between incidences of ESRD with respect to sex, ethnicity, age and regions, (2) to compare incidence rates in the diabetic and non-diabetic population, and (3) to investigate time trends. The systematic review was conducted according to the PRISMA group guidelines by performing systematic literature searches in the biomedical databases until January 3rd 2015; thirty-two studies were included. Among patients with incident type 1 diabetes the 30-year cumulative incidence ranged from 3.3% to 7.8%. Among patients with prevalent diabetes, incidence rates of ESRD due to all causes ranged from 132.0 to 167.0 per 100,000 person-years, whereas incidence rates of ESRD due to diabetic nephropathy varied from 38.4 to 804.0 per 100,000 person-years. The incidence of ESRD in the diabetic population was higher compared to the non-diabetic population, and relative risks varied from 6.2 in the white population to 62.0 among Native Americans. The results regarding time trends were inconsistent. The review conducted demonstrates the considerable variation of incidences of ESRD among the diabetic population. Consistent findings included an excess risk when comparing the diabetic to the non-diabetic population and ethnic differences. We recommend that newly designed studies should use standardized methods for the determination of ESRD and population at risk.

Cardiovascular risk in autoimmune disorders: role of asymmetric dimethylarginine

Mounting evidence indicates that cardiovascular events are a main cause of excessive mortality of autoimmune disorders like type I diabetes mellitus and rheumatic diseases. Inflammation and endothelial dysfunction, independent predictors to cardiovascular disease, are hallmarks of autoimmunity. Asymmetric dimethylarginine (ADMA), an endogenous nitric oxide synthase inhibitor, can cause or contribute to the inflammatory syndrome and endothelial dysfunction. Recently, elevated ADMA levels have been demonstrated in many autoimmune diseases, suggesting that ADMA might play an important role for the associated manifestations of cardiovascular disease. In the review, we discuss the role of ADMA in the excessive cardiovascular morbidity and mortality associated with autoimmune diseases.

Access to renal transplantation in the diabetic population-effect of comorbidities and body mass index

BACKGROUND

In this study, we hypothesized that higher level of comorbidity and greater body mass index (BMI) may mediate the association between diabetes and access to transplantation.

METHODS

We used data from the United States Renal Data System (01/01/2000-24/09/2007; n = 619,151). We analyzed two outcomes using Cox model: (i) time to being placed on the waiting list or transplantation without being listed and (ii) time to transplantation after being listed. Two primary Cox models were developed based on different levels of adjustment.

RESULTS

In Cox models adjusted for a priori defined potential confounders, history of diabetes was associated with reduced transplant access (compared with non-diabetic population) - both for wait-listing/transplant without being listed (hazard ratio, HR = 0.80, p < 0.001) and for transplant after being listed (HR = 0.72, p < 0.001). In Cox models adjusted for BMI and comorbidity index along with the potential confounders, history of diabetes was associated with shorter time to wait-listing or transplantation without being listed (HR = 1.07, p < 0.001), and there was no significant difference in time to transplantation after being listed (HR = 1.01, p = 0.42).

CONCLUSION

We demonstrated that higher level of comorbidity and greater BMI mediate the association between diabetes and reduced access to transplantation.