Insulin Resistance and Oxidant Stress: An Interrelation With Deleterious Renal Consequences?

Prognostic Nutritional Index Combined with Triglyceride-Glucose Index to Contrast a Nomogram for Predicting Contrast-Induced Kidney Injury in Type 2 Diabetes Mellitus Patients with Acute Coronary Syndrome After Percutaneous Coronary Intervention

Objective

Our objective was to develop and validate a nomogram model aiming at predicting the risk of contrast-induced acute kidney injury (CI-AKI) following percutaneous coronary intervention (PCI) in patients suffering from type 2 diabetes mellitus (T2DM) and also diagnosed with acute coronary syndrome (ACS).

Methods

The study gathered data from 722 T2DM patients with ACS who received PCI treatment at the Affiliated Hospital of Xuzhou Medical University between February 2019 and December 2022, serving as the training set. Considering the validation set, the study included 217 patients who received PCI at the East Affiliated Hospital of Xuzhou Medical University. The patients were classified into CI-AKI and non-CI-AKI groups. The study employed univariate and multivariate logistic analysis for identifying independent risk factors for CI-AKI, followed by developing a predictive nomogram model for CI-AKI risk using R software. The predictive performance and clinical utility of the nomogram were assessed through internal and external validation, utilizing the areas under the receiver operating characteristic curve (AUC-ROC), the Hosmer-Lemeshow test and calibration correction curve, and decision curve analysis (DCA).

Results

The nomogram comprised four variables: age, estimated glomerular filtration rate (eGFR), triglyceride-glucose (TyG) index, and prognostic nutritional index (PNI). The AUC-ROC were 0.785 (95% confidence interval (CI) 0.729-0.841) and 0.802 (95% CI 0.699-0.905) for the training and validation cohorts, respectively, indicating a high discriminative ability of the nomogram. The calibration assessment and decision curve analysis have substantiated the strong concordance and clinical usefulness of the aforementioned.

Conclusion

The nomogram exhibits favorable discrimination and accuracy, enabling it to visually and individually identify pre-procedure high-risk patients, and possesses a predictive capacity regarding CI-AKI incidence after PCI in patients diagnosed with both T2DM and ACS.

Effect of sorghum and barley-containing bread on plasma total polyphenols, antioxidant status and inflammation in healthy subjects

The aim of this study was to investigate the effect of bread incorporated with whole-grain red sorghum and barley flours on biomarkers of oxidative stress and inflammation in humans. In a randomized cross-over study, 20 healthy subjects consumed either control bread made of all-purpose wheat flour only or bread containing 40% whole-grain red sorghum and barley flours (20% each), with a washout period of 1-2 week. The test breads were fed at breakfast after 12 h fast. Blood samples were collected at baseline (fasting) and 2 h after intake of breads. Plasma total polyphenols, total antioxidant capacity (T-AOC), superoxide dismutase (SOD) activity, thiobarbituric acid reactive substances (TBARS) and highly sensitive C-reactive protein were assessed. Compared to fasting values, the 2 h postprandial levels of plasma total polyphenols (P = 0.001), T-AOC (P = 0.031) and SOD activity (P = 0.026) were significantly higher following consumption of sorghum and barley-containing bread (SBB). Moreover, net changes in plasma total polyphenols (P = 0.001), T-AOC (P = 0.047) and SOD activity (P = 0.035) were significantly higher following consumption of SBB. In conclusion, bread containing whole-grain red sorghum and barely flours enhanced plasma total polyphenols and antioxidant status and hence its consumption would modulate biomarkers of cardio-metabolic health.

A Clinical Nomogram Based on the Triglyceride-Glucose Index to Predict Contrast-Induced Acute Kidney Injury after Percutaneous Intervention in Patients with Acute Coronary Syndrome with Diabetes Mellitus

The aim of the study was to investigate the factors influencing contrast-induced acute kidney injury (CI-AKI) after percutaneous intervention (PCI) in patients with acute coronary syndrome (ACS) with diabetes mellitus (DM). A total of 1073 patients with ACS combined with DM who underwent PCI at the Affiliated Hospital of Xuzhou Medical University were included in this study. We divided the patients into the CI-AKI and non-CI-AKI groups according to whether CI-AKI occurred or not. The patients were then randomly assigned to the training and validation sets at a proportion of 7 : 3. Based on the results of the LASSO regression and multivariate analyses, we determined that the subtypes of ACS, age, multivessel coronary artery disease, hyperuricemia, low-density lipoprotein cholesterol, triglyceride-glucose index, and estimated glomerular filtration rate were independent predictors on CI-AKI after PCI in patients with ACS combined with DM. Using the above indicators to develop the nomogram, the AUC-ROC of the training and validation sets were calculated to be 0.811 (95% confidence interval (CI): 0.766-0.844) and 0.773 (95% CI: 0.712-0.829), respectively, indicating high prediction efficiency. After verification by the Bootstrap internal verification, we found that the calibration curves showed good agreement between the nomogram predicted and observed values. And the DCA results showed that the nomogram had a high clinical application. In conclusion, we constructed and validated the nomogram to predict CI-AKI risk after PCI in patients with ACS and DM. The model can provide a scientific reference for predicting the occurrence of CI-AKI and improving the prognosis of patients.

Comparative Efficacy of Lobeglitazone Versus Pioglitazone on Albuminuria in Patients with Type 2 Diabetes Mellitus

INTRODUCTION

The aim of this analysis was to evaluate the efficacy of lobeglitazone on albuminuria at 24 weeks of follow-up in patients with type 2 diabetes mellitus (T2DM) compared with pioglitazone using data from a randomized, double-blinded phase III trial.

METHODS

In the phase III trial, patients who were inadequately controlled with metformin received 0.5 mg of lobeglitazone or 15 mg of pioglitazone for 24 weeks. Post hoc, exploratory analysis was used to investigate mean changes from baseline in the urine albumin-creatinine ratio (UACR) between the lobeglitazone (N = 104) and pioglitazone (N = 101) treatment groups.

RESULTS

After 24 weeks of treatment, UACR was slightly decreased in the lobeglitazone group (- 4.3 mg/g creatinine [Cr]) compared to baseline and slightly increased in the pioglitazone group (5.2 mg/g Cr), with no change in the estimated glomerular filtration rate in either group; this difference was not statistically significant (P = 0.476). The incidence of new-onset microalbuminuria (2.4%) and the progression of albuminuria by > 1 stage (2.9%) in the lobeglitazone group were lower than the respective values in the pioglitazone group (6.8 and 6.1%, respectively). Of the patients in the lobeglitazone group, 50% exhibited regression to normoalbuminuria, compared to 39.3% of the patients in the pioglitazone. In subjects in the lobeglitazone group with micro- and macroalbuminuria, UACR tended to be more decreased and HbA1c was more reduced compared to those with normoalbuminuria (P = 0.014).

CONCLUSION

Lobeglitazone had a tendency to improve albuminuria in patients with T2DM and had comparable effects on albuminuria as pioglitazone which has demonstrated beneficial effects.

TRIAL REGISTRATION

ClinicalTrials.gov identifier, NCT01106131.

Carbonyl stress induces hypertension and cardio-renal vascular injury in Dahl salt-sensitive rats

One major precursor of carbonyl stress, methylglyoxal (MG), is elevated in the plasma of chronic kidney disease (CKD) patients, and this precursor contributes to the progression of vascular injury, hypertension and renal injury in diabetic nephropathy patients. This molecule induces salt-sensitive hypertension via a reactive oxygen species-mediated pathway. We examined the role of MG in the pathogenesis of hypertension and cardio–renal injury in Dahl salt-sensitive (Dahl S) rats, which is a rat model of CKD. Nine-week-old Dahl S rats were fed a 1% NaCl diet, and 1% MG was added to their drinking water for up to 12 weeks. Blood pressure and cardio–renal injuries were compared with rats treated with tap water alone. The angiotensin II receptor blocker (ARB), candesartan (10 mg kg⁻¹ day⁻¹), was administered to MG Dahl S rats to determine the impact of this drug on the pathogenesis of MG-induced CKD. A progressive increase in systolic blood pressure was observed (123±1–148±5 mm Hg) after 12 weeks of MG administration. MG administration significantly increased urinary albumin excretion, glomerular sclerosis, tubular injury, myocardial collagen content and cardiac perivascular fibrosis. MG also enhanced the renal expression of Nɛ-carboxyethyl-lysine (an advanced glycation end product), 8-hydroxydeoxyguanosine (a marker of oxidative stress), macrophage (ED-1) positive cells (a marker of inflammation) and nicotinamide adenine dinucleotide phosphate (NAD(P)H) oxidase activity. Candesartan treatment for 4 weeks significantly reduced these parameters. These results suggest that MG-induced hypertension and cardio–renal injury and increased inflammation and carbonyl and oxidative stress, which were partially preventable by an ARB.

Green tea extract reduces blood pressure, inflammatory biomarkers, and oxidative stress and improves parameters associated with insulin resistance in obese, hypertensive patients

Green tea (GT) consumption is known to be associated with enhanced cardiovascular and metabolic health. The purpose of this study is to examine the hypothesis that supplementation with GT alters insulin resistance and associated cardiovascular risk factors in obese, hypertensive patients. In a double-blind, placebo-controlled trial, 56 obese, hypertensive subjects were randomized to receive a daily supplement of 1 capsule that contained either 379 mg of GT extract (GTE) or a matching placebo, for 3 months. At baseline and after 3 months of treatment, the anthropometric parameters, blood pressure, plasma lipid levels, glucose levels, creatinine levels, tumor necrosis factor α levels, C-reactive protein levels, total antioxidant status, and insulin levels were assessed. Insulin resistance was evaluated according to the homeostasis model assessment-insulin resistance protocol. After 3 months of supplementation, both systolic and diastolic blood pressures had significantly decreased in the GTE group as compared with the placebo group (P < .01). Considerable (P < .01) reductions in fasting serum glucose and insulin levels and insulin resistance were observed in the GTE group when compared with the placebo group. Serum tumor necrosis factor α and C-reactive protein were significantly lower, whereas total antioxidant status increased in the GTE group compared with the placebo (P < .05). Supplementation also contributed to significant (P < .05) decreases in the total and low-density lipoprotein cholesterol and triglycerides, but an increase in high-density lipoprotein cholesterol. In conclusion, daily supplementation with 379 mg of GTE favorably influences blood pressure, insulin resistance, inflammation and oxidative stress, and lipid profile in patients with obesity-related hypertension.

PPAR-γ agonism for cardiovascular and renal protection

Diabetes mellitus is an established risk factor for cardiovascular disease and the leading cause of end-stage renal disease in the Western World. Thiazolidinediones (TZDs) represent a class of antidiabetic agents that exert their glucose-lowering effects by reducing insulin resistance, through stimulation of a type of nuclear receptor, called peroxisome proliferator-activated receptor-γ. Apart from improving glycemic control, TZDs were shown to exert beneficial effects on several components of the metabolic syndrome and cardiovascular risk markers. Furthermore, background and human studies have shown that TZDs reduce urinary albumin and protein excretion and interfere with most of the pathogenentic pathways involved in the development and progression of diabetic nephropathy. On the other hand, currently used TZDs have side effects, most important of which is fluid retention leading to wait gain and heart failure deterioration. With regards to cardiovascular outcomes, the anticipated benefit of TZDs was demonstrated for pioglitazone, whereas a series of previous meta-analyses linking rosiglitazone treatment with increased risk of myocardial infarction and cardiovascular death raised uncertainty around the cardiovascular safety of rosiglitazone. This article will discuss the effects of TZDs on established and emerging cardiovascular risk factors, the data on possible beneficial renal effects of these compounds, and the existing evidence from large-scale clinical trials and meta-analyses on their effects on cardiovascular outcomes, aiming to provide an overview of the cardio- and renoprotective properties of these drugs.

Effect of thiazolidinediones on albuminuria and proteinuria in diabetes: a meta-analysis

BACKGROUND

Because of the major clinical and economic burden of diabetic nephropathy, new therapeutic tools to delay its progression are needed. Recent studies suggest that thiazolidinediones have renal benefits. We aimed to evaluate the effect of thiazolidinediones on urinary albumin and protein excretion in patients with diabetes mellitus.

STUDY DESIGN

Systematic review and meta-analysis by searching MEDLINE/PubMed, EMBASE, and Cochrane CENTRAL databases (1991 to September 2009).

SETTING & POPULATION

Patients with diabetes mellitus.

SELECTION CRITERIA FOR STUDIES

Randomized controlled trials.

INTERVENTION

Thiazolidinediones (rosiglitazone and pioglitazone) compared with placebo or other antidiabetic agents.

OUTCOMES

Weighted (WMDs) and standardized mean differences (SMDs) for changes in urine albumin or protein excretion between the thiazolidinedione and control groups.

RESULTS

Of 171 originally identified articles, 15 studies (5 with rosiglitazone and 10 with pioglitazone) involving 2,860 patients were included in the analysis. In participants with baseline normo- or microalbuminuria, the WMD of proportional changes between the thiazolidinedione and control groups in urinary albumin excretion measured using time-specified collections was -64.8% (95% CI, -75.6 to -53.9) and the WMD of changes in albumin-creatinine ratio was -24.8% (95% CI, -39.6 to -10.0). Overall, in participants with normo- and microalbuminuria, thiazolidinedione treatment was associated with a significant decrease in urinary albumin excretion (SMD, -0.6 units of standard deviation [SD]; 95% CI, -0.8 to -0.4). Similarly, thiazolidinediones were associated with a significant decrease in urinary protein excretion in patients with proteinuria (SMD, -1.1 units of SD; 95% CI, -1.8 to -0.4).

LIMITATIONS

Significant heterogeneity across included studies in several subgroup analyses; patient-level data not available.

CONCLUSIONS

Treatment with thiazolidinediones significantly decreases urinary albumin and protein excretion in patients with diabetes. This finding calls for clinical trials with hard renal outcomes to elucidate the potential benefits of thiazolidinediones on diabetic nephropathy.

Redox control of renal function and hypertension

Loss of redox homeostasis and formation of excessive free radicals play an important role in the pathogenesis of kidney disease and hypertension. Free radicals such as reactive oxygen species (ROS) are necessary in physiologic processes. However, loss of redox homeostasis contributes to proinflammatory and profibrotic pathways in the kidney, which in turn lead to reduced vascular compliance and proteinuria. The kidney is susceptible to the influence of various extracellular and intracellular cues, including the renin-angiotensin-aldosterone system (RAAS), hyperglycemia, lipid peroxidation, inflammatory cytokines, and growth factors. Redox control of kidney function is a dynamic process with reversible pro- and anti-free radical processes. The imbalance of redox homeostasis within the kidney is integral in hypertension and the progression of kidney disease. An emerging paradigm exists for renal redox contribution to hypertension.

Thiazolidinediones and diabetic nephropathy: need for a closer examination?

Diabetic nephropathy is an important public health issue and a major challenge for modern nephrology, as it is the primary cause of end-stage renal disease. In addition to established risk factors for diabetic nephropathy progression (ie, hyperglycemia and hypertension), current knowledge suggests that other factors can be involved. Population studies show that insulin resistance and hyperinsulinemia are also associated with chronic kidney disease, and several background mechanisms could explain this relationship. The hypoglycemic class of thiazolidinediones that act through reduction of insulin resistance were found to protect against renal injury in diabetic animals and to reduce urinary albumin excretion in patients with type 2 diabetes and microalbuminuria. This renoprotective action is supported by relevant studies showing that thiazolidinediones act beneficially on most of the players involved in diabetic nephropathy progression. Recent studies have raised uncertainty about the cardiovascular safety of thiazolidinediones. After the latter issue is resolved, however, it would appear very interesting to conduct specific studies in patients with overt diabetic nephropathy to determine the effect of these agents on proteinuria and kidney disease progression.

Increase in oxidative stress but not in antioxidant capacity with advancing stages of chronic kidney disease

BACKGROUND/AIMS

Increased oxidative stress in chronic kidney disease (CKD) was suggested to be both a cause and an effect of renal injury. However, the evolution of oxidant stress from early stages of renal function decline is not fully clear. This study aimed to determine the oxidant-antioxidant balance across the whole range of renal function.

METHODS

A total of 116 patients with CKD (85 predialysis patients divided into groups according to CKD stage, and 31 patients with end-stage renal disease (ESRD) on hemodialysis treatment), as well as 29 healthy subjects were evaluated. Plasma levels of 15-F(2t)-isoprostane (15-F(2t)-IsoP), a valid marker of oxidant stress, as well as total antioxidant capacity (TAC) and serum levels of vitamin E were measured in all participants.

RESULTS

Plasma 15-F(2t)-IsoP levels were higher in predialysis and ESRD patients compared to healthy subjects and were progressively increasing with advancing CKD stages (p < 0.001). In contrast, plasma TAC was similar between healthy subjects and predialysis patients, and presented a small reduction in ESRD patients (p < 0.001). Vitamin E levels were higher in healthy subjects compared to any other group (p < 0.001) and slightly higher in ESRD patients compared to predialysis patients (p < 0.01), but did not differ significantly between the groups of predialysis patients. Plasma 15-F(2t)-IsoP levels were inversely correlated with estimated glomerular filtration rate in predialysis patients (r = -0.65, p < 0.001).

CONCLUSIONS

This study shows that 15-F(2t)-IsoP levels increase progressively with advancing CKD stages, whereas TAC and vitamin E levels remain rather stable with the loss of renal function and change only in patients with ESRD.