Why is diabetes mellitus a risk factor for contrast-induced nephropathy?

High-mobility group box 1 and its related receptors: potential therapeutic targets for contrast-induced acute kidney injury

Percutaneous coronary intervention (PCI) is a crucial diagnostic and therapeutic approach for coronary heart disease. Contrast agents' exposure during PCI is associated with a risk of contrast-induced acute kidney injury (CI-AKI). CI-AKI is characterized by a sudden decline in renal function occurring as a result of exposure to intravascular contrast agents, which is associated with an increased risk of poor prognosis. The pathophysiological mechanisms underlying CI-AKI involve renal medullary hypoxia, direct cytotoxic effects, endoplasmic reticulum stress, inflammation, oxidative stress, and apoptosis. To date, there is no effective therapy for CI-AKI. High-mobility group box 1 (HMGB1), as a damage-associated molecular pattern molecule, is released extracellularly by damaged cells or activated immune cells and binds to related receptors, including toll-like receptors and receptor for advanced glycation end product. In renal injury, HMGB1 is expressed in renal tubular epithelial cells, macrophages, endothelial cells, and glomerular cells, involved in the pathogenesis of various kidney diseases by activating its receptors. Therefore, this review provides a theoretical basis for HMGB1 as a therapeutic intervention target for CI-AKI.

Do Sodium-Glucose Cotransporter 2 Inhibitors Decrease the Risk of Contrast-Associated Acute Kidney Injury in Patients with Type II Diabetes Mellitus?

BACKGROUND

The risk of contrast-associated acute kidney injury is relatively higher in patients with diabetes mellitus compared to non-diabetics. Recent trials have revealed the renoprotective effects of sodium-glucose cotransporter 2 (SGLT2) inhibitors. We aimed to investigate the possible preventive effect of SGLT2 inhibitors against contrast-associated acute kidney injury in the diabetic population who underwent coronary angiography with a diagnosis of stable angina or acute coronary syndrome.

METHODS

This was a cross-sectional and single-center study. We enrolled 345 patients with type II diabetes mellitus who were divided into 2 groups: using an SGLT2 inhibitor (group 1; n = 133) in addition to other antidiabetic medication and not using an SGLT2 inhibitor (group 2; n = 212). Both groups were compared in terms of contrast-associated acute kidney injury incidence. We also compared groups for the duration of hospitalization.

RESULTS

Baseline characteristics (age, sex, risk factors and medications) and laboratory findings were similar between the 2 groups. The means of administered contrast volume were also similar (160.42 (± 70.31) mL vs. 158.72 (± 81.24) mL, P = 0.83) between groups 1 and 2, respectively. We found that contrast-associated acute kidney injury incidence was significantly higher in group 2 compared to group 1 (n = 56 (26.4%) vs. n = 12 (9.0%), P < 0.001). The duration of hospitalization was significantly longer in group 2 (3.25 (± 2.03) days) than in group 1 (2.54 (± 1.39) days) (P = 0.001).

CONCLUSION

We found that contrast-associated acute kidney injury was significantly lower, and the duration of hospitalization was significantly shorter in diabetic patients using SGLT2 inhibitors compared to non-users.

Impact of Hyperglycemia on Complication and Mortality after Transarterial Chemoembolization for Hepatocellular Carcinoma

BACKGRUOUND

Current guidelines regarding periprocedural glycemic control to prevent complications after nonsurgical invasive procedures are insufficient. Transarterial chemoembolization (TACE) is a widely used treatment for unresectable hepatocellular carcinoma. We aimed to investigate the association between diabetes mellitus (DM) per se and the degree of hyperglycemia with postprocedural complications after TACE.

METHODS

A total of 22,159 TACE procedures performed at Seoul National University Hospital from 2005 to 2018 were retrospectively analyzed. The associations between DM, preprocedural glycosylated hemoglobin (HbA1c), and periprocedural average glucose with postprocedural adverse outcomes were evaluated. The primary outcome was occurrence of postprocedural bacteremia. Secondary outcomes were acute kidney injury (AKI), delayed discharge and death within 14 days. Periprocedural glucose was averaged over 3 days: the day of, before, and after the TACE procedures. Propensity score matching was applied for procedures between patients with or without DM.

RESULTS

Periprocedural average glucose was significantly associated with bacteremia (adjusted odds ratio per 50 mg/dL of glucose, 1.233; 95% confidence interval, 1.071 to 1.420; P=0.004), AKI, delayed discharge, and death within 14 days. DM per se was only associated with bacteremia and AKI. Preprocedural HbA1c was associated with delayed discharge. Average glucose levels above 202 and 181 mg/dL were associated with a significantly higher risk of bacteremia and AKI, respectively, than glucose levels of 126 mg/dL or lower.

CONCLUSION

Periprocedural average glucose, but not HbA1c, was associated with adverse outcomes after TACE, which is a nonsurgical invasive procedure. This suggests the importance of periprocedural glycemic control to reduce postprocedural complications.

Effect of Serum C-Peptide Levels on the Development of Contrast-Induced Nephropathy in Diabetic Patients Undergoing Coronary Angiography

Contrast-induced nephropathy (CIN) is an important cause of morbidity and mortality, in patients with diabetes who undergo coronary angiography (CAG). It is known that serum C-peptide has renoprotective effects in diabetic nephropathy. Patients with diabetes (n = 552) who underwent CAG in our center between January 2020 and December 2021 were included, retrospectively. The patients were divided into 2 groups: not-developing CIN (group 1) and developing CIN (group 2). CIN developed in 128 (23.1%) of the patients with diabetes who underwent CAG. C-peptide, albumin, hemoglobin, hematocrit, initial creatinine, ejection fraction (EF), were significantly lower in the group that developed CIN compared with the group that did not (P < .05, for all). In correlation analysis, creatinine increase rate (ΔCr) was negatively correlated with C-peptide, hematocrit, and ejection fraction (r = -.241, P < .001; r = -.135, P < .001; r = -.194, P = .001; respectively). In logistic regression analysis, C-peptide level (Odds Ratio: .404, 95% Confidence Interval: .286-.571, P < .001) was an independent predictor of CIN. In the present study, C-peptide level was an independent predictor of CIN in patients with diabetes. This study suggests that low levels of C-peptide are associated with a greater risk of CIN.

The Effects of Coenzyme Q10 on Contrast-Induced Acute Kidney Injury in Type 2 Diabetes: A Randomized Clinical Trial

Contrast-induced acute kidney injury (CI-AKI) is a frequent challenge following the injection of contrast media and its subsequent oxidative stress. The aim of the present study was to evaluate the preventive effects of coenzyme Q10 (Q10), as a mitochondrial-targeted antioxidant in CI-AKI in diabetic patients, who account for a large proportion of angiographic cases. A total of 118 diabetic patients were randomly assigned to receive 120 mg of oral coenzyme Q10 (Q10 group) or placebo (Placebo group) for four days, starting 24 hours before contrast media injection. Blood urea nitrogen (BUN), serum and urinary creatinine, estimated glomerular filtration rate (eGFR), urinary malondialdehyde (UMDA), urinary total antioxidant capacity (UTAC), and urinary mitochondrial to nuclearDNA ratios (mtDNA/nDNA ratio) were evaluated before and after the treatment period. Urine sediments were also evaluated to report the urine microscopy score (UMS).The levels of BUN, serum and urine creatinine, and UMS were similar in the Q10 and placebo groups. EGFR was lower in the Q10 group before the treatment (p=0.013) but not after. The urinary mtDNA/nDNA ratio was 3.05±1.68 and 3.69±2.58 in placebo and Q10 groups, but UTAC was found to be lower in Q10 both before (p=0.006) and after the treatment (p<0.001). The incidence of CI-AKI was 14.40% and the mtDNA/nNDA ratio was similar between CI-AKI and non-CI-AKI patients. In conclusion, Q10 treatment shows no favorable effect on prevention of CI-AKI or a urinary mtDNA/nDNA ratio among diabetic patients.

Predicting Contrast-induced Renal Complications

Chronic kidney disease is an independent risk factor for the development of coronary artery disease and overlaps with other risk factors such as hypertension and diabetes. Percutaneous coronary intervention is a cornerstone of therapy for coronary artery disease and requires contrast media, which can lead to renal injury. Identifying patients at risk for contrast-associated acute kidney injury (CA-AKI) is critical for preventing kidney damage, which is associated with both short- and long-term mortality. Determination of the potential risk for CA-AKI and a new need for dialysis using validated risk prediction tools identifies patients at high risk for this complication. Identification of patients at risk for renal injury after contrast exposure is the first critical step in prevention. Contrast media volume, age and sex of the patient, a history of chronic kidney disease and/or diabetes, clinical presentation, and hemodynamic and volume status are factors known to predict incident contrast-induced nephropathy. Recognition of at-risk patient subpopulations allows for targeted, efficient, and cost-effective strategies to reduce the risk of renal complications resulting from contrast media exposure.

Association between elevated CHA2DS2-VASC score and contrast-induced nephropathy among patients undergoing percutaneous coronary intervention: a systematic review and meta-analysis

BACKGROUND

Promising results with the CHA2DS2-VASc risk score (CVRS) have been reported for the prediction of contrast-induced nephropathy (CIN). The aim of this study is to consolidate all the data available and examine the association between elevated CVRS and the incidence of CIN in patients undergoing percutaneous coronary intervention (PCI).

METHODS

We systematically searched PubMed, Embase, and Scopus for abstracts and full-text articles from inception to May 2022. Studies were included if they evaluated the association between a high CVRS and the incidence of CIN in patients undergoing PCI. Data were integrated using the random-effects, generic inverse variance method of DerSimonian and Laird. Prospero registration: CRD42022334065.

RESULTS

Seven studies from 2016 to 2021 with a total of 7,401 patients were included. In patients undergoing PCI, a high CVRS (≥2: Odds ratio [OR]:2.98, 95% confidence interval [95% CI] 2.25-3.94, p < .01, I2 = 1%, ≥3: OR 4.46, 95% CI 2.27-8.78, p < .01, I2=56% and ≥4: OR:2.75, 95% CI 1.76-4.30, p < .01, I2 = 11%) was significantly associated with an increase incidence for CIN. Subgroup analyses were done in patients with acute coronary syndrome, and association with CIN remained statistically significant (≥2: OR 2.93, 95% CI 2.11-4.07, p < .01, I2=22%and ≥4: OR:2.24, 95% CI 1.36-3.69, p < .01, I2 = 0%,).

CONCLUSION

In patients undergoing PCI, an elevated CVRS is associated with an increased risk for CIN. More rigorous studies are needed to clarify this association and to identify strategies to reduce CIN.

Prediction of the development of contrast‑induced nephropathy following percutaneous coronary artery intervention by machine learning

Contrast-induced nephropathy (CIN) is associated with increased mortality and morbidity in patients with coronary artery disease undergoing elective percutaneous coronary intervention(PCI). We developed a machine learning-based risk stratification model to predict contrast-induced nephropathy after PCI. A study retrospectively enrolling 240 patients eligible for PCI from December 2017 to May 2020 was performed. CIN was defined as a rise in serum creatinine levels ≥0.5 mg/dL or ≥25% from baseline within 72 h after surgery. Eight machine learning methods were performed based on clinical variables. Shapley Additive exPlanation values were also used to interpret the best-performing prediction models. Development of CIN was found in 37 patients(16.5%) after PCI. There were 11 significant predictors of CIN, including uric acid, peripheral vascular disease, cystatin C, creatine kinase-MB, haemoglobin, N-terminal pro-brain natriuretic peptide, age, diabetes, systemic immune-inflammatory index, total protein, and low-density lipoprotein. Regarding the efficacy of the machine learning model that accurately predicted CIN, SVM exhibited the most outstanding AUC value of 0.784. The SHAP and radar plots were used to illustrate the positive and negative effects of the 11 features attributed to the SVM. Machine learning models have the potential to identify the risk of CIN for elective PCI patients.

Contrast-Associated Acute Kidney Injury: Definitions, Epidemiology, Pathophysiology, and Implications

Acute kidney injury (AKI) is a common occurrence after contrast media administration. Hemodynamic changes, direct tubular injury, and reactive oxygen species are the proposed mechanisms involved in AKI. However, in most scenarios, it is not possible to establish causality despite extensive clinical evaluation, therefore, contrast-associated AKI (CA-AKI) has become a widely accepted term to define AKI postcontrast. CA-AKI is associated with worse clinical outcomes including cardiovascular events and mortality; however, discussions are ongoing whether CA-AKI is a marker of an increased risk of adverse outcomes or a mediator of such outcomes.

Gliflozins, Erythropoietin, and Erythrocytosis: Is It Renal Normoxia- or Hypoxia-Driven?

The introduction of gliflozins in the management of type 2 diabetes mellitus leads to a better control of hyperglycemia, obesity, hypertension, dyslipidemia, and fluid retention. Most importantly, it also improves renal survival and reduces major cardiovascular events and mortality. Gliflozins were also found to induce erythropoietin (EPO) synthesis, leading to reticulocytosis and erythropoiesis. The mechanism(s) by which gliflozins induce erythropoiesis is a matter of debate. Although the canonical pathway of triggering EPO synthesis is through renal tissue hypoxia, it has been suggested that improved renal oxygenation may facilitate EPO synthesis via non-canonical routes. The latter proposes that the recovery of peritubular interstitial fibroblasts producing erythropoietin (EPO) is responsible for enhanced erythropoiesis. According to this hypothesis, enhanced glucose/sodium re-uptake by proximal tubules in uncontrolled diabetes generates cortical hypoxia, with injury to these cells. Once transport workload declines with the use of SGLT2i, they recover and regain their capacity to produce EPO. In this short communication, we argue that this hypothesis may be wrong and propose that gliflozins likely induce EPO through the documented intensification of renal hypoxia at the corticomedullary junction, related to the translocation of tubular transport from cortical segments to medullary thick ascending limbs. We propose that gliflozins, through intensified hypoxia in this region, trigger local EPO synthesis in peritubular interstitial cells via the canonical pathway of blocking HIF-prolyl hydroxylases (that initiate HIF alpha degradation), with the consequent stabilization of HIF-2 signal and an apocrinic induction of EPO in these same cells.

Acute kidney injury in diabetic patients: A narrative review

Diabetes mellitus (DM) is the most common cause of chronic kidney disease, which leads to end-stage renal failure worldwide. Glomerular damage, renal arteriosclerosis, and atherosclerosis are the contributing factors in diabetic patients, leading to the progression of kidney damage. Diabetes is a distinct risk factor for acute kidney injury (AKI) and AKI is associated with faster advancement of renal disease in patients with diabetes. The long-term consequences of AKI include the development of end-stage renal disease, higher cardiovascular and cerebral events, poor quality of life, and high morbidity and mortality. In general, not many studies discussed extensively "AKI in DM." Moreover, articles addressing this topic are scarce. It is also important to know the cause of AKI in diabetic patients so that timely intervention and preventive strategies can be implemented to decrease kidney injury. Aim of this review article is to address the epidemiology of AKI, its risk factors, different pathophysiological mechanisms, how AKI differs between diabetic and nondiabetic patients and its preventive and therapeutic implications in diabetics. The increasing occurrence and prevalence of AKI and DM, as well as other pertinent issues, motivated us to address this topic.

Virtual Monoenergetic Imaging of Lower Extremities Using Dual-Energy CT Angiography in Patients with Diabetes Mellitus

BACKGROUND

Type 2 diabetes mellitus (DM) is the most common metabolic disorder in the world and an important risk factor for peripheral arterial disease (PAD). CT angiography represents the method of choice for the diagnosis, pre-operative planning, and follow-up of vascular disease. Low-energy dual-energy CT (DECT) virtual mono-energetic imaging (VMI) has been shown to improve image contrast, iodine signal, and may also lead to a reduction in contrast medium dose. In recent years, VMI has been improved with the use of a new algorithm called VMI+, able to obtain the best image contrast with the least possible image noise in low-keV reconstructions.

PURPOSE

To evaluate the impact of VMI+ DECT reconstructions on quantitative and qualitative image quality in the evaluation of the lower extremity runoff.

MATERIALS AND METHODS

We evaluated DECT angiography of lower extremities in patients suffering from diabetes who had undergone clinically indicated DECT examinations between January 2018 and January 2023. Images were reconstructed with standard linear blending (F_0.5) and low VMI+ series were generated from 40 to 100 keV, in an interval of 15 keV. Vascular attenuation, image noise, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) were calculated for objective analysis. Subjective analysis was performed using five-point scales to evaluate image quality, image noise, and diagnostic assessability of vessel contrast.

RESULTS

Our final study cohort consisted of 77 patients (41 males). Attenuation values, CNR, and SNR were higher in 40-keV VMI+ reconstructions compared to the remaining VMI+ and standard F_0.5 series (HU: 1180.41 ± 45.09; SNR: 29.91 ± 0.99; CNR: 28.60 ± 1.03 vs. HU 251.32 ± 7.13; SNR: 13.22 ± 0.44; CNR: 10.57 ± 0.39 in standard F_0.5 series) (p < 0.0001). Subjective image rating was significantly higher in 55-keV VMI+ images compared to the other VMI+ and standard F_0.5 series in terms of image quality (mean score: 4.77), image noise (mean score: 4.39), and assessability of vessel contrast (mean value: 4.57) (p < 0.001).

CONCLUSIONS

DECT 40-keV and 55-keV VMI+ showed the highest objective and subjective parameters of image quality, respectively. These specific energy levels for VMI+ reconstructions could be recommended in clinical practice, providing high-quality images with greater diagnostic suitability for the evaluation of lower extremity runoff, and potentially needing a lower amount of contrast medium, which is particularly advantageous for diabetic patients.

Acute kidney injury in diabetes mellitus: Epidemiology, diagnostic, and therapeutic concepts

Acute kidney injury (AKI) and diabetes mellitus (DM) are public health problems that cause a high socioeconomic burden worldwide. In recent years, the landscape of AKI etiology has shifted: Emerging evidence has demonstrated that DM is an independent risk factor for the onset of AKI, while an alternative perspective considers AKI as a bona fide complication of DM. Therefore, it is necessary to systematically characterize the features of AKI in DM. In this review, we summarized the epidemiology of AKI in DM. While focusing on circulation- and tissue-specific microenvironment changes after DM, we described the active cellular and molecular mechanisms of increased kidney susceptibility to AKI under DM stress. We also reviewed the current diagnostic and therapeutic strategies for AKI in DM recommended in the clinic. Updated recognition of the epidemiology, pathophysiology, diagnosis, and medications of AKI in DM is believed to reveal a path to mitigate the frequency of AKI and DM comorbidity that will ultimately improve the quality of life in DM patients.

Diabetic Proteinuria Revisited: Updated Physiologic Perspectives

Albuminuria, a hallmark of diabetic nephropathy, reflects not only injury and dysfunction of the filtration apparatus, but is also affected by altered glomerular hemodynamics and hyperfiltration, as well as by the inability of renal tubular cells to fully retrieve filtered albumin. Albuminuria further plays a role in the progression of diabetic nephropathy, and the suppression of glomerular albumin leak is a key factor in its prevention. Although microalbuminuria is a classic manifestation of diabetic nephropathy, often progressing to macroalbuminuria or overt proteinuria over time, it does not always precede renal function loss in diabetes. The various components leading to diabetic albuminuria and their associations are herein reviewed, and the physiologic rationale and efficacy of therapeutic interventions that reduce glomerular hyperfiltration and proteinuria are discussed. With these perspectives, we propose that these measures should be initiated early, before microalbuminuria develops, as substantial renal injury may already be present in the absence of proteinuria. We further advocate that the inhibition of the renin–angiotensin axis or of sodium–glucose co-transport likely permits the administration of a normal recommended or even high-protein diet, highly desirable for sarcopenic diabetic patients.

Preoperative Fasting Blood Glucose Levels and the Risk of Contrast-Induced Nephropathy in Patients With Diabetes and Pre-diabetes Undergoing Coronary Arteriography or Percutaneous Coronary Intervention: A Cross-Sectional Study

Diabetes mellitus is an independent risk factor for contrast-induced nephropathy (CIN) in patients undergoing coronary arteriography/percutaneous coronary intervention (CAG/PCI). We evaluated whether preoperative fasting blood glucose (FBG) levels in diabetic and pre-diabetic patients who underwent CAG/PCI influenced the occurrence of CIN. From June 1, 2020, to February 28, 2021, 687 patients were divided into five groups based on their preoperative FBG levels. Blood samples were collected at admission and at 48 hours and 72 hours after the procedure to determine serum creatinine levels. The P value for trend was used to analyze the trend between preoperative FBG levels and the increased risk of CIN. Univariable and multivariable logistic regression analysis were used to exclude the influence of confounding factors, and some high-risk confounders were selected for subgroup analysis. The results of our cross-sectional study show that elevated preoperative FBG levels are independently associated with the risk of CIN in diabetic and pre-diabetic patients undergoing CAG/PCI. Furthermore, the incidence of CIN gradually increases with the rise in preoperative FBG levels. Patients with elevated preoperative FBG at admission should be carefully monitored and more active measures should be taken to prevent CIN.

Hyperglycemia on Admission Predicts Acute Kidney Failure and Renal Functional Recovery among Inpatients

BACKGROUND

Hyperglycemia is associated with adverse outcomes in hospitalized patients. We aimed to assess the impact of glucose levels upon admission on the subsequent deterioration or improvement of kidney function in inpatients with a focus on diabetes or reduced baseline kidney function as possible modifiers of this effect.

METHODS

Running a retrospective cohort analysis, we compared patients with normal vs. high glucose levels upon admission. We applied multivariable logistic regression models to study the association between baseline glucose levels with subsequent renal and clinical outcomes. Interaction terms were used to study a possible modifier effect of diabetes.

RESULTS

Among 95,556 inpatients (52% males, mean age 61 years), 15,675 (16.5%) had plasma glucose higher than 180 mg/dL, and 72% of them were diabetics. Patients with higher glucose at presentation were older, with a higher proportion of co-morbid conditions. Rates of acute kidney injury (AKI), acute kidney functional recovery (AKR), and mortality were proportional to reduced renal function. AKI, AKR, and mortality were almost doubled in patients with high baseline glucose upon admission. Multivariable analysis with interaction terms demonstrated an increasing adjusted probability of all events as glucose increased, yet this association was observed principally in non-diabetic patients.

CONCLUSIONS

Hyperglycemia is associated with AKI, AKR, and mortality in non-diabetic inpatients in proportion to the severity of their acute illness. This association diminishes in diabetic patients, suggesting a possible impact of treatable and easily reversible renal derangement in this population.

Tubular Injury Causing Protracted Glycosuria Following Withdrawal of a Sodium-Glucose Cotransporter 2 (SGLT2) Inhibitor: A Possible Role in the Development of Protracted Hypoglycemia and Ketoacidosis

We herein present the case of a 45-year-old diabetic woman who developed diabetic ketoacidosis following the administration of dapagliflozin, a sodium-glucose cotransporter 2 (SGLT2) inhibitor. The patient had been diagnosed with diabetes three years previously and was being treated with multiple daily injections of insulin. Metformin hydrochloride and dapagliflozin were added seven months and 11 months later, respectively. Her clinical course was uneventful until the onset of influenza. She then discontinued insulin and oral medications voluntarily. On arrival at the hospital, she was found to be in a state of ketoacidosis, and promptly received insulin and saline infusion. In retrospect, the initial amount of glucose infused was insufficient, and the hypoglycemia was thought to have been prolonged. This phenomenon may also have affected her long-term urinary glucose excretion. Her urinary L-type fatty acid-binding protein (L-FABP) level was found to be markedly elevated (48.8 μg/g·Cr, reference value < 8.4 μg/g·Cr) as was her urinary β2-microglobulin level (9,230 μg/L, reference value < 230 μg/L). Patients with SGLT-2 inhibitor-associated diabetic ketoacidosis often exhibit protracted hyperglycosuria, in which acute proximal renal tubular dysfunction is considered to be etiologically implicated.

Predictors of contrast-induced nephropathy in ST-elevation myocardial infarction patients undergoing primary percutaneous coronary intervention

Background

Contrast-induced nephropathy (CIN) is a serious complication with primary percutaneous coronary intervention (PPCI). We aimed to study the different predictors of CIN and determine the cutoff point of contrast volume (CV)/creatinine clearance (CrCl) and the applicability of CHA2DS2-VASC score in the prediction of CIN after PPCI in ST-elevation myocardial infarction (STEMI) patients. Four hundred patients presented with STEMI and eligible for primary PCI were included in the study. Patients with GFR < 30 ml/min were excluded from the study.

Results

Fifty-four (13.5%) patients who developed CIN who were older (64.20 ± 13.16 vs. 55.80 ± 10.58) had a higher prevalence of diabetes mellitus (DM), hypertension (HTN), and female gender than those without CIN. They also had a higher Killip class and lower hemoglobin (HB) level (P < 0.05) compared to those with no CIN. The incidence of no CIN was (85.8%) in the low-risk Mehran score group and 14.2% in the moderate-risk group, and all patients of high and very high score group developed CIN (P<0.001). Multiple logistic regression showed that old age (OR= 1.06, 95% CI= 1.02–1.11, P< 0.001), female sex (OR= 3.1, 95% CI= 2.65–6.99, P= 0.02), high Mehran score (OR=2.48, 95% CI= 1.98–6.24, P= 0.01), CV/CrCl > 2.8 (odds ratio=1.45, 95% CI= 1.22–2.01, P= 0.03), and CHA2DS2-VASC score > 2 (odds ratio=1.90, 95% CI= 1.76–2.11, P= 0.04) were predictors of CIN.

Conclusions

Old age, female sex, high Mehran score, CHADS2-VASC score > 2, CV/CrCl > 2.8 were predictors of CIN in STEMI patients who underwent PPCI.

Acute Kidney Injury Following Admission with Acute Coronary Syndrome: The Role of Diabetes Mellitus

Purpose: To evaluate the role of diabetes mellitus in the incidence, risk factors, and outcomes of AKI (acute kidney injury) in patients admitted with ACS (acute coronary syndrome). Methods: We performed a comparative evaluation of ACS patients with vs. without DM who developed AKI enrolled in the biennial ACS Israeli Surveys (ACSIS) between 2000 and 2018. AKI was defined as an absolute increase in serum creatinine (≥0.5 mg/dL) or above 1.5 mg/dL or new renal replacement therapy upon admission with ACS. Outcomes included 30-day major adverse cardiovascular events (MACE) and 1-year all-cause mortality. Results: The current study included a total of 16,879 patients, median age 64 (IQR 54–74), 77% males, 36% with DM. The incidence of AKI was significantly higher among patients with vs. without DM (8.4% vs. 4.7%, p < 0.001). The rates of 30-day MACE (40.8% vs. 13.4%, p < 0.001) and 1-year mortality (43.7% vs. 10%, p < 0.001) were significantly greater among diabetic patients who developed vs. those who did not develop AKI respectively, yet very similar among patients that developed AKI with vs. without DM (30-day MACE 40.8% vs. 40.3%, p = 0.9 1-year mortality 43.7 vs. 44.8%, p = 0.8, respectively). Multivariate analyses adjusted to potential confounders, showed similar independent predictors of AKI among patients with and without DM, comprising; older age, chronic kidney disease, congestive heart failure, and peripheral arterial disease. Conclusions: Although patients with DM are at much greater risk for AKI when admitted with ACS, the independent predictors of AKI and the worse patient outcomes when AKI occurs, are similar irrespective to DM status.

Predictive Value of Lymphocyte-to-monocyte Ratio in Patients with Contrast-induced Nephropathy After Percutaneous Coronary Intervention for Acute Coronary Syndrome

Background and Objectives

Lymphocyte-to-monocyte ratio (LMR) has emerged as a new indirect marker of inflammation, which is associated with adverse outcomes in cardiovascular diseases. The aim of this study was to evaluate whether admission LMR is associated with contrast-induced nephropathy (CIN) in patients who underwent percutaneous coronary intervention for acute coronary syndrome (ACS).

Methods

A total of 873 patients were assessed. LMR was calculated via dividing lymphocyte count by monocyte count.

Results

LMR was significantly lower in the with-CIN group. ROC analysis showed that the LMR ratios <2.52 predicted CIN development with sensitivity of 66.3% and specificity of 55.8%. Multivariate analysis showed that eGFR, admission glucose, and LMR were independent predictors of CIN in patients with ACS.

Conclusion

LMR is an easily accessible marker and could be used as a predictor of CIN in patients with ACS undergoing percutaneous coronary intervention.

Increasing Angiogenesis Factors in Hypoxic Diabetic Wound Conditions by siRNA Delivery: Additive Effect of LbL-Gold Nanocarriers and Desloratadine-Induced Lysosomal Escape

Impaired wound healing in people with diabetes has multifactorial causes, with insufficient neovascularization being one of the most important. Hypoxia-inducible factor-1 (HIF-1) plays a central role in the hypoxia-induced response by activating angiogenesis factors. As its activity is under precise regulatory control of prolyl-hydroxylase domain 2 (PHD-2), downregulation of PHD-2 by small interfering RNA (siRNA) could stabilize HIF-1α and, therefore, upregulate the expression of pro-angiogenic factors as well. Intracellular delivery of siRNA can be achieved with nanocarriers that must fulfill several requirements, including high stability, low toxicity, and high transfection efficiency. Here, we designed and compared the performance of layer-by-layer self-assembled siRNA-loaded gold nanoparticles with two different outer layers-Chitosan (AuNP@CS) and Poly L-arginine (AuNP@PLA). Although both formulations have exactly the same core, we find that a PLA outer layer improves the endosomal escape of siRNA, and therefore, transfection efficiency, after endocytic uptake in NIH-3T3 cells. Furthermore, we found that endosomal escape of AuNP@PLA could be improved further when cells were additionally treated with desloratadine, thus outperforming commercial reagents such as Lipofectamine® and jetPRIME®. AuNP@PLA in combination with desloratadine was proven to induce PHD-2 silencing in fibroblasts, allowing upregulation of pro-angiogenic pathways. This finding in an in vitro context constitutes a first step towards improving diabetic wound healing with siRNA therapy.

The Application of Functional Magnetic Resonance Imaging in Type 2 Diabetes Rats With Contrast-Induced Acute Kidney Injury and the Associated Innate Immune Response

AIMS

Contrast-induced acute kidney injury (CI-AKI) is the third most common in-hospital acquired AKI, and its mechanism is not fully clear. Its morbidity increases among populations with chronic kidney disease (CKD), older age, diabetes mellitus (DM), and so on. Immediate and effective noninvasive diagnostic methods are lacking, so CI-AKI often prolongs hospital stays and increases extra medical costs. This study aims to explore the possibility of diagnosing CI-AKI with functional magnetic resonance imaging (fMRI) based on type 2 DM rats. Moreover, we attempt to reveal the immune response in CI-AKI and to clarify why DM is a predisposing factor for CI-AKI.

METHODS

A type 2 DM rat model was established by feeding a high-fat and high-sugar diet combined with streptozotocin (STZ) injection. Iodixanol-320 was the contrast medium (CM) administered to rats. Images were obtained with a SIEMENS Skyra 3.0-T magnetic resonance imager. Renal histopathology was evaluated using H&E staining and immunohistochemistry (IHC). The innate immune response was revealed through western blotting and flow cytometry.

RESULTS

Blood oxygenation level-dependent (BOLD) imaging and intravoxel incoherent motion (IVIM) imaging can be used to predict and diagnose CI-AKI effectively. The R 2 ∗ value (r > 0.6, P < 0.0001) and D value (| r| > 0.5, P < 0.0001) are strongly correlated with histopathological scores. The NOD-like receptor pyrin 3 (NLRP3) inflammasome participates in CI-AKI and exacerbates CI-AKI in DM rats. Moreover, the percentages of neutrophils and M1 macrophages increase dramatically in rat kidneys after CM injection (neutrophils range from 56.3 to 56.6% and M1 macrophages from 48 to 54.1% in normal rats, whereas neutrophils range from 85.5 to 92.4% and M1 macrophages from 82.1 to 89.8% in DM rats).

CONCLUSIONS/INTERPRETATION

BOLD and IVIM-D can be effective noninvasive tools in predicting CI-AKI. The innate immune response is activated during the progression of CI-AKI and DM will exacerbate this progression.

Protection of coenzyme Q10 against contrast-induced acute kidney injury in male diabetic rats

BACKGROUND

Diabetes mellitus (DM) is a major risk factor for contrast-induced acute kidney injury (CI-AKI). DM and CI-AKI result in oxidative damage and inflammation that can be reduced when treated with the coenzyme Q-10 (CoQ10). The aim of this study was to investigate the therapeutic potential of CoQ10 in renal function, renal hemodynamics, oxidative profile and renal histology in diabetic rats subjected to CI-AKI.

METHODS

Wistar rats, male, randomized into five groups: citrate: control animals received citrate buffer (streptozotocin vehicle, 0.4 mL); Tween: control animals of CoQ10 treatment received 1% Tween 80 (CoQ10 vehicle, 0.5 mL); DM: animals that received streptozotocin (60 mg/kg); DM + IC: DM animals treated with iodinated contrast (IC, 6 mL/kg); DM + IC + CoQ10: DM animals treated with CoQ10 (10 mg/kg) and that received IC (6 mL/kg). The protocols lasted 4 weeks. An evaluation was made to measure renal function, inulin clearance and serum creatinine, renal hemodynamics by renal blood flow (RBF) and renal vascular resistance (RVR), markers of oxidative stress such as urinary peroxides and nitrate, lipid peroxidation, thiols in renal tissue and renal histological analysis.

RESULTS

DM animals showed reduced renal function, which was followed by an increase inserum creatinine and significant reduction of inulin clearance and RBF. It was noticed an increase in RVR and redox imbalance with higher urinary peroxides and nitrate lipid peroxidation levels with depletion of thiols in renal tissue. IC treatment exacerbated these changes in DM + IC. CoQ10 administration ameliorated renal function, prevented hemodynamic changes and neutralized oxidative damage and progression of the histologic damage in the DM + IC + CoQ10 group.

CONCLUSION

This study demonstrated the renoprotection properties of CoQ10 in an experimental model of risk factor of DM for CI-AKI. CoQ10 presented an antioxidant effect on the CI-AKI in male diabetic rats by improving renal function and renal hemodynamics, preserving morphology and reducing oxidative stress.

Biomarker evidence for distal tubular damage but cortical sparing in hospitalized diabetic patients with acute kidney injury (AKI) while on SGLT2 inhibitors

Background

Inhibitors of sodium-glucose co-transporter-2 (SGLT2i) were found to improve renal outcome in diabetic patients in large prospective randomized trials. Yet, SGLT2i may acutely reduce kidney function through volume depletion, altered glomerular hemodynamics or intensified medullary hypoxia leading to acute tubular injury (ATI). The aim or this study was to prospectively assess the pathophysiology of acute kidney injury (AKI) in patients hospitalized while on SGLT2i, differing ATI from pre-renal causes using renal biomarkers.

Methods

Serum and urine Neutrophil Gelatinase-Associated Lipocalin (NGAL) and Kidney Ischemia Molecule (KIM)-1, markers of distal and proximal tubular injury, respectively, were determined in 46 diabetic patients who were on SGLT2i upon hospitalization with an acute illness.

Results

Serum and urine NGAL, but not KIM-1, were significantly increased in 21 of the patients who presented with AKI upon admission, as compared with 25 patients that maintained kidney function. Both serum and urinary NGAL correlated with the degree of impaired renal function, which in many cases was likely the result of additional acute renal perturbations, such as sepsis.

Conclusions

Increased urinary and serum NGAL indicates that ATI, principally affecting distal tubular segments, may develop in some of the patients hospitalized with an acute illness and AKI while on SGLT2i. It is suggested that intensified medullary hypoxia by SGLT2i might be detrimental in this injury. By contrast, concomitantly unaltered KIM-1 might reflect improved cortical oxygenation by SGLT2i, and may explain an overall reduced risk of AKI with SGLT1i in large series. The independent potential of SGLT2i to inflict medullary hypoxic damage should be explored further.

Glycosylated hemoglobin levels and the risk for contrast-induced nephropathy in diabetic patients undergoing coronary arteriography/percutaneous coronary intervention

Backgrounds

Diabetes mellitus is an independent risk factor for Contrast-induced nephropathy (CIN) in patients undergoing Coronary arteriography (CAG)/percutaneous coronary intervention (PCI). Glycosylated hemoglobin (HbA1c) is the gold standard to measure blood glucose control, which has important clinical significance for evaluating blood glucose control in diabetic patients in the past 3 months. This study aimed to assess whether preoperative HbA1c levels in diabetic patients who received CAG/PCI impacted the occurrence of postoperative CIN.

Methods

We reviewed the incidence of preoperative HbA1c and postoperative CIN in 670 patients with CAG/PCI from January 1, 2020 to October 30, 2020 and divided the preoperative HbA1c levels into 5 groups. Blood samples were collected at admission, 48 h and 72 h after operation to measure the Scr value of patients. Categorical variables were compared using a chi-square test, and continuous variables were compared using an analysis of variance. Fisher’s exact test was used to compare the percentages when the expected frequency was less than 5. Univariable and multivariable logistic regression analysis was used to exclude the influence of confounding factors, and P for trend was used to analyze the trend between HbA1c levels and the increased risk of CIN.

Results

Patients with elevated HbA1c had higher BMI, FBG, and LDL-C, and they were more often on therapy with hypoglycemic agents, Insulin and PCI. They also had higher basal, 48 h and 72 h Scr. The incidence of CIN in the 5 groups of patients were: 9.8, 11.9, 15.2, 25.3, 48.1%. (p < 0.0001) The multivariate analysis confirmed that in the main high-risk subgroup, patients with elevated HbA1C levels (≥8.8%) had a higher risk of CIN disease. Trend test showed the change of OR (1.000,1.248,1.553,2.625,5.829).

Conclusions

Studies have shown that in diabetic patients undergoing CAG/PCI, elevated HbA1c is independently associated with the risk of CIN, and when HbA1c > 9.5%, the incidence of CIN trends increase. Therefore, we should attach great importance to patients with elevated HbA1c at admission and take more active measures to prevent CIN.

Contrast-Induced Nephropathy: A Review of Mechanisms and Risks

Radiological procedures utilizing intravenous iodinated contrast agents are being widely utilized for both therapeutic and diagnostic purposes. This has resulted in an increasing incidence of procedure-related, contrast-induced nephropathy (CIN). CIN is commonly defined as a decline in kidney function occurring in a narrow time window after administration of iodinated contrast agents. Although self-limiting in most cases, CIN carries a risk of more permanent renal insufficiency, dialysis, and death. It remains a common and serious complication among at-risk patients after exposure of contrast agents. Therefore, it is important to identify patients who are at risk during early stages to implement preventative strategies to decrease the incidence of CIN. Minimizing the amount of contrast administered and providing adequate hydration are the cornerstones of an effective preventative approach. This review focuses on the basic concepts of CIN and summarizes the current understanding of its pathophysiology. In addition, it provides practical recommendations with respect to CIN prevention and management.

Factors Contributing to an Efficacious Endovascular Treatment for Acute Ischemic Stroke in Asian Population

Although randomized control trials about endovascular treatment (EVT) of emergent large vessel occlusion (LVO) have demonstrated the success of mechanical thrombectomy as the choice of treatment, a wide range of caveats remain unaddressed. Asian patients were rarely included in the trials, thereby raising the question of whether the treatment could be generalized. In addition, there remains a concern on the feasibility of the method with respect to its application against intracranial atherosclerosis (ICAS)-related LVO, frequently observed in the Asian population. It is important to include evidence on ICAS LVO from Asian countries in the future for a comprehensive understanding of LVO etiology. Besides the issues with EVT, prognostic concerns in diabetes patients, acute kidney injury following EVT, neuroprotective management against reperfusion injury, and other peri-EVT issues should be considered in clinical practice. In the current article, we present an in-depth review of the literature that revises information pertaining to such concerns.

A High Triglyceride-Glucose Index Is Associated With Contrast-Induced Acute Kidney Injury in Chinese Patients With Type 2 Diabetes Mellitus

Background and Objectives

Triglyceride-glucose (TyG) is an emerging vital indicator of insulin resistance and is associated with increased risk of T2DM and cardiovascular events. We aimed to explore the TyG index and contrast-induced acute kidney injury (CI-AKI) in patients with type 2 diabetes who underwent coronary angiology.

Methods

This study enrolled 928 patients with suspected coronary artery disease who underwent coronary angiology or percutaneous coronary intervention in Zhongda hospital. Patient data were divided into quartiles according to the TyG index: group 1: TyG ≤ 8.62; group 2: 8.629.45. CI-AKI was diagnosed according to the KIDIGO criteria. Demographic data, hematological parameters, coronary angiology data, and medications were all recorded. We calculated the TyG index using the following formula: ln [fasting TG (mg/dL)×FPG (mg/dL)/2].

Results

Patients who developed CI-AKI exhibited significantly higher TyG index levels compared to patients who did not develop CI-AKI. The incidence of CI-AKI sharply increased with increasing TyG. Univariate and multivariate analysis identified TyG as an independent risk factor for CI-AKI. The AUC of the ROC curve was as high as 0.728 when the value of TyG was 8.88. The corresponding sensitivity was as high as 94.9%. Adding the variable TyG to the model for predicting CI-AKI risk further increased the predictive value of the model from 80.4% to 82%.

Conclusions

High TyG is closely associated with increased incidence of CI-AKI, demonstrating that TyG is an independent risk factor for CI-AKI. TyG has potentially predictive value for CI-AKI and may play a crucial role in risk stratification in clinical practice.

The renoprotective effects of Heme Oxygenase-1 during contrast-induced acute kidney injury in preclinical diabetic models

OBJECTIVES

Contrast-induced acute kidney injury (CI-AKI) is an important clinical problem that can be aggravated by diabetes mellitus, a major risk factor. However, heme oxygenase-1 (HO-1), a promising therapeutic target, can exert antioxidant effects against CI-AKI. Thus, we investigated the role of HO-1 in CI-AKI in the presence of diabetes mellitus.

METHODS

Twenty-eight male Wistar rats weighing 250-300g were subjected to left uninephrectomy, and concomitantly, diabetes induced by streptozotocin (65 mg/kg). After 12 weeks, iodinated contrast (meglumine ioxithalamate, 6 mL/kg) and hemin (HO-1 inducer-10 mg/k) were administered 60 min before iodinated contrast treatment. The rats were randomly divided into four groups: control, diabetes mellitus (DM), DM iodinated contrast (DMIC), and DMIC hemin (DMICH). Kidney function, albuminuria, oxidative profile, and histology were assessed. All experimental data were subjected to statistical analyses.

RESULTS

CI-AKI in preclinical diabetic models decreased creatinine clearance and increased urinary neutrophil gelatinase-associated lipocalin (NGAL) levels and the degree of albuminuria. Additionally, the levels of oxidative and nitrosative stress metabolites (urinary peroxides, thiobarbituric acid-reactive substances, and NO) were elevated, while thiol levels in kidney tissue were reduced. Kidney histology showed tubular cell vacuolization and edema. HO-1 inducer treatment improved kidney function and reduced urinary the NGAL levels. The oxidative profile showed an increase in the endogenous thiol-based antioxidant levels. Additionally, the tubular injury score was reduced following HO-1 treatment.

CONCLUSIONS

Our findings highlight the renoprotective effects of HO-1 in CI-AKI and preclinical diabetic models. Therefore, HO-1 ameliorates kidney dysfunction, reduces oxidative stress, and prevents cell necrosis.

A distinctive distribution of hypoxia-inducible factor-1α in cultured renal tubular cells with hypoperfusion simulated by coverslip placement

Chronic hypoxia in the renal tubulointerstitium plays a key role in the progression of chronic kidney disease (CKD). It is therefore important to investigate tubular hypoxia and the activity of hypoxia-inducible factor (HIF)-1α in response to hypoxia. Rarefaction of the peritubular capillary causes hypoperfusion in CKD; however, the effect of hypoperfusion on HIFs has rarely been investigated. We induced hypoperfusion caused by coverslip placement in human kidney-2 cells, and observed an oxygen gradient under the coverslip. Immunocytochemistry of HIF-1α showed a doughnut-shaped formation on the edge of a pimonidazole-positive area, which we named the "HIF-ring". The oxygen tension of the HIF-ring was estimated to be between approximately 4 mmHg and 20 mmHg. This result was not compatible with those of past research showing HIF-1α accumulation in the anoxic range with homogeneous oxygen tension. We further observed the presence of a pH gradient under a coverslip, as well as a shift of the HIF ring due to changes in the pH of the culture medium, suggesting that the HIF ring was formed by suppression of HIF-1α related to low pH. This research demonstrated that HIF-1α activation mimics the physiological state in cultured cells with hypoperfusion.

Contrast-associated acute kidney injury: An update of risk factors, risk factor scores, and preventive measures

As lifespans lengthen, age-related diseases such as cardiovascular disease and diabetes are becoming more prevalent. Correspondingly, the use of contrast agents for medical imaging is also becoming more common, and there is increasing awareness of contrast-associated acute kidney injury (CA-AKI). There is no specific treatment for CA-AKI, and clinicians currently focus on prevention, interventions that alter its pathogenesis, and identification of risk factors. Although the incidence of CA-AKI is low in the general population, the risk of CA-AKI can reach 20% to 30% in patients with multiple risk factors. Many models have been applied in the clinic to assess the risk factors for CA-AKI, enable identification of high-risk groups, and improve clinical management. Hypotonic or isotonic contrast media are recommended to prevent CA-AKI in high-risk patients. Patients with risk factors should avoid using contrast media multiple times within a short period of time. All nephrotoxic drugs should be stopped at least 24 h before the administration of contrast media in high-risk populations, and adequate hydration is recommended for all patients. This review summarizes the pathophysiology of CA-AKI and the progress in diagnosis and differential diagnosis; updates the risk factors and risk factor scoring systems; reviews the latest advances related to prevention and treatment; discusses current problems in epidemiological studies; and highlights the importance of identifying high-risk subjects to control modifiable risk factors and use of a rating scale to estimate the risk and implement appropriate prevention strategies.

Reduced glutathione does not further reduce contrast-induced nephropathy in elderly patients with diabetes receiving percutaneous coronary intervention

Objective

To investigate the preventive effect of hydration combined with reduced glutathione on contrast-induced nephropathy (CIN) after coronary intervention therapy in elderly Chinese patients with diabetes.

Methods

Patients with diabetes aged ≥65 years, who received percutaneous coronary intervention (PCI) between 1 August 2016 and 31 December 2018, were enrolled and randomized into two groups: patients treated with hydration combined with reduced glutathione (treatment group) and patients who received hydration alone (controls). Serum creatinine and creatinine clearance levels were measured in all patients before PCI and then daily for 3 days after PCI. Occurrence of CIN (the primary endpoint) was defined as serum creatinine value 25% or 44.2 mmol/l (0.5 mg/dl) above baseline at 72 h after an exposure to contrast medium.

Results

A total of 396 patients were included (treatment group, n = 204; and controls, n = 192). The CIN occurrence rate in the treatment and control group was 5.88% and 6.77%, respectively, with no statistically significant between-group difference.

Conclusion

In elderly patients with diabetes receiving PCI, the risk of CIN was not effectively lowered by hydration combined with reduced glutathione.

The impact of diabetes mellitus on acute kidney injury after coronary artery bypass grafting

Background

Diabetes mellitus(DM) is an indicator affects postoperative mortality and morbidity after coronary artery bypass grafting (CABG). Acute kidney injury (AKI) is one of the frequent postoperative complications after CABG. This multi-centre register study designed to investigate the impact of DM on postoperative AKI in primary isolated CABG patients.

Methods

We included all patients (n = 4325) from Jiangsu Province CABG register who underwent primary isolated CABG from September 2017 to August 2019. The patients were divided into 3 groups: No-DM group(n = 3067), DM-oral group (DM with oral hypoglycemic agents, n = 706) and DM-insulin group (DM with insulin treatment, n = 552). The development and severity of AKI were based on Acute Kidney Injury Network (AKIN) criteria.

Results

There were totally 338, 108 and 145 patients developed AKI in No-DM, DM-oral and DM-insulin group respectively. Comparing with No-DM group, DM-oral group had a higher rate of AKI(χ² = 10.071, p = 0.002), DM-insulin group had a higher rate(χ² = 94.042, p<0.001) and severity of AKI(χ² = 10.649, p = 0.005). The adjusted odds ratio for AKI was 1.26 (95% CI 1.03–1.57) in DM-oral group and 3.92 (95% CI 3.27–5.16) in DM-insulin group, in comparison with No-DM group.

Conclusions

Independent of baseline renal function or cardiac function, DM was associated with an increased risk of AKI after CABG, especially in patients with insulin treatment, who also had a higher severity of AKI.

Renin-angiotensin-aldosterone system inhibition decreased contrast-associated acute kidney injury in chronic kidney disease patients

BACKGROUND/PURPOSE

Chronic kidney disease (CKD) is a risk factor for contrast associated acute kidney injury (CA-AKI). The risk of renin-angiotensin-aldosterone system inhibitor (RASi) use in patients with CKD before the administration of contrast is not clear.

METHODS

In this nested case-control study, 8668 patients received contrast computed tomography (CT) from 2013 to 2018 during index administration in a multicenter hospital cohort. The identification of AKI is based on the Kidney Disease: Improving Global Outcomes (KDIGO) serum creatinine criteria within 48 h after contrast medium used.

RESULTS

Finally, 986 patients (age, 63.36 ± 12.22; men, 72.92%) with CKD (estimated glomerular filtration rate (eGFR) = 35.0 ± 19.8 mL/min/1.73 m²) were eligible for analysis. After the index date, RASi users (n = 315) were less likely to develop CA-AKI (13.65% vs 30.4%, p < 0.001), and had a lower hospital mortality (8.25% vs 19.23%, p < 0.001) compared with non-users. The pre-contrast use of RASi decrease the risk of AKI (OR, 0.342, p < 0.001) and hospital mortality (OR, 0.602, p = 0.045). Even a few defined daily doses (DDDs) of RASi treatment, more than 0.02 prior to contrast CT could attenuate CA-AKI. The hospital mortality was higher in RASi non-users if their eGFR value was more than 17.9 mL/min/1.73 m².

CONCLUSION

RASi use in patients with CKD prior to contrast CT has the potential to mitigate the incidence of AKI and hospital mortality. Even a low dose of RASi will noticeably decrease the risk of AKI and will not increase the risk of hyperkalemia.

The Mechanism of Contrast-Induced Acute Kidney Injury and Its Association with Diabetes Mellitus

Contrast-induced acute kidney injury (CI-AKI) is the third most common hospital-acquired AKI after AKI induced by renal perfusion insufficiency and nephrotoxic drugs, taking great adverse effects on the prognosis and increasing hospital stay and medical cost. Diabetes nephropathy (DN) is a common chronic complication of DM (diabetes mellitus), and DN is an independent risk factor for chronic kidney disease (CKD) and CI-AKI. The incidence of CI-AKI significantly increases in patients with renal injury, especially in DM-related nephropathy. The etiology of CI-AKI is not fully clear, and research studies on how DM becomes a facilitated factor of CI-AKI are limited. This review describes the mechanism from three aspects. ① Pathophysiological changes of CI-AKI in kidney under high-glucose status (HGS). HGS can enhance the oxidative stress and increase ROS which next causes stronger vessel constriction and insufficient oxygen supply in kidney via vasoactive substances. HGS also aggravates some ion pump load and the latter increases oxygen consumption. CI-AKI and HGS are mutually causal, making the kidney function continue to decline. ② Immunological changes of DM promoting CI-AKI. Some innate immune cells and pattern recognition receptors (PRRs) in DM and/or DN may respond to some damage-associated molecular patterns (DAMPs) formed by CI-AKI. These effects overlap with some pathophysiological changes in hyperglycemia. ③ Signaling pathways related to both CI-AKI and DM. These pathways involved in CI-AKI are closely associated with apoptosis, inflammation, and ROS production, and some studies suggest that these pathways may be potential targets for alleviating CI-AKI. In conclusion, the pathogenesis of CI-AKI and the mechanism of DM as a predisposing factor for CI-AKI, especially signaling pathways, need further investigation to provide new clinical approaches to prevent and treat CI-AKI.

Predicting Contrast-Induced Renal Complications

Chronic kidney disease is a major risk factor for developing coronary artery disease, serving as an independent risk factor while overlapping with other risk factors. Percutaneous coronary intervention is a cornerstone of therapy for coronary artery disease and requires contrast media, which can contribute to renal injury. Identifying patients at risk for contrast-induced nephropathy is critical for preventing renal injury, which is associated with short- and long-term mortality. Determination of the potential risk for contrast-induced nephropathy and a new need for dialysis using validated risk prediction tools is a method of identifying patients at high risk for this complication.

Is there association between statin usage and contrast-associated acute kidney injury after intravenous administration of iodine-based contrast media in enhanced computed tomography?

OBJECTIVES

Contrast-induced acute kidney injury (CI-AKI) is one of the leading causes of new-onset renal failure in hospitalized patients. Statin has been evaluated for its protective effect against CI-AKI but rarely in patients receiving intravenous (IV) administrations of iodine-based contrast media for enhanced computed tomography (CT).

METHODS

In total, 12,371 patients who underwent contrast-enhanced abdominopelvic CT were retrospectively reviewed and stratified into statin users and statin nonusers. Subgroup analyses comparing high-intensity statins with low- to moderate-intensity statins were conducted within statin users and similar comparisons were performed within statin users stratified based on baseline eGFR.

RESULTS

Overall, CI-AKI events did not occur less in statin users compared with non-statin users (p = 0.342). Within statin users, CI-AKI events did not decrease in high-intensity statin users compared with low- to moderate-intensity statin users (p = 0.355). Moreover, no significant difference in CI-AKI events was found between high-intensity statin users and low- to moderate-intensity statin users even after stratifying the patients with baseline eGFR.

CONCLUSIONS

Collectively, statin was not significantly associated with the risk of CI-AKI events in patients undergoing contrast-enhanced abdominopelvic CT and high-intensity statins did not show significant association with CI-AKI over low- to moderate-intensity statins in the subgroup analysis.

KEY POINTS

• Statin is not associated with risk of CI-AKI events in patients undergoing intravenous administration of contrast-enhanced CT. • CI-AKI incidence among high-intensity statin users was not significantly different from that of low- to moderate-intensity statin users.

Pathophysiology of Contrast-Induced Acute Kidney Injury

Passing contrast media through the renal vascular bed leads to vasoconstriction. The perfusion decrease leads to ischemia of tubular cells. Through ischemia and direct toxicity to renal tubular cells, reactive oxygen species formation is increased, enhancing the effect of vasoconstrictive mediators and decreasing the bioavailability of vasodilative mediators. Reactive oxygen species formation leads to oxidative damage to tubular cells. These interacting pathways lead to tubular necrosis. In the pathophysiology of contrast-induced acute kidney injury, low osmolar and iso-osmolar agents have theoretic advantages and disadvantages; however, clinically the difference in incidence of contrast-induced acute kidney injury has not changed.

Meta-analysis of effect of renin-angiotensin-aldosterone system blockers on contrast-induced nephropathy

Background:

The purpose of this study was to systematically evaluate the effect of renin–angiotensin–aldosterone system blockers on the incidence of contrast-induced nephropathy in patients undergoing coronary angiography or percutaneous coronary intervention.

Methods:

A systematic literature search of several databases was conducted to identify studies that met the inclusion criteria. A total of 12 studies with 14 trials that performed studies on a total of 4864 patients (2484 treated with renin–angiotensin–aldosterone system blockers and 2380 in the control group) were included. The primary endpoint was the overall incidence of contrast-induced nephropathy. Analyses were performed with STATA version 12.0.

Results:

The overall contrast-induced nephropathy incidence in renin–angiotensin–aldosterone system blocker and control groups was 10.43% and 6.81%, respectively. The pooled relative risk of contrast-induced nephropathy incidence was 1.22 (95% confidence interval: 0.81–1.84) in the renin–angiotensin–aldosterone system blocker group. An increased risk of developing contrast-induced nephropathy in the renin–angiotensin–aldosterone system blocker group was observed among older people, non-Asians, chronic users, and studies with larger sample size, and the pooled RRs and 95% confidence intervals were 2.02 (1.21–3.36), 2.30 (1.41–3.76), 1.69 (1.10–2.59) and 1.83 (1.28–2.63), respectively.

Conclusions:

Intervention with renin–angiotensin–aldosterone system blockers was associated with an increased risk of contrast-induced nephropathy among non-Asians, chronic users, older people, and studies with larger sample size. Large clinical trials with strict inclusion criteria are needed to confirm our results and to evaluate the effect further.

Smad3 promotes AKI sensitivity in diabetic mice via interaction with p53 and induction of NOX4-dependent ROS production

The incidence and severity of acute kidney injury (AKI) is increased yearly in diabetic patients. Although the mechanisms for this remain unclear, the prevention of AKI in diabetic nephropathy is feasible and of value. As we detected highly activation of TGF-β/Smad3 signaling in both human biopsy and mouse model of diabetic nephropathy, we hypothesized that Smad3 activation in diabetic kidneys may increase AKI sensitivity. We tested our hypothesis in vitro using TGF-β type II receptor (TGF-βRII) disrupted tubular epithelial cells (TECs) and in vivo in mice with streptozotocin (STZ)-induced diabetic nephropathy before the induction of ischemia/reperfusion (I/R) injury. We found that high glucose (HG)-cultured TECs showed increased inflammation, apoptosis and oxidative stress following hypoxia/reoxygenation (H/R) injury. Disruption of TGF-βRII attenuated cell injury induced by H/R in HG-treated TECs. Consistently, Smad3 knockdown in diabetic kidney attenuated I/R-induced AKI. Mechanistically, Smad3 binds to p53 and enhances p53 activity in cells treated with HG and H/R, which may lead to TECs apoptosis. Additionally, ChIP assay showed that Smad3 bound with the promoter region of NOX4 and induced ROS production and inflammation. In conclusion, our results demonstrate that Smad3 promotes AKI susceptibility in diabetic mice by interacting with p53 and NOX4.

•

Smad3 activation in diabetic kidneys may increase AKI sensitivity.

•

Blockade of Smad3 in diabetic kidney may both prevent AKI and CKD progression.

•

Smad3 interacts with p53 to enhance TECs apoptosis.

•

Smad3 binds with promoter region of NOX4 to induce ROS production and inflammation.

Evaluation of Renal Pathophysiological Processes Induced by an Iodinated Contrast Agent in a Diabetic Rabbit Model Using Intravoxel Incoherent Motion and Blood Oxygenation Level-Dependent Magnetic Resonance Imaging

OBJECTIVE

To examine the potential of intravoxel incoherent motion (IVIM) and blood oxygen level-dependent (BOLD) magnetic resonance imaging for detecting renal changes after iodinated contrast-induced acute kidney injury (CI-AKI) development in a diabetic rabbit model.

MATERIALS AND METHODS

Sixty-two rabbits were randomized into 2 groups: diabetic rabbits with the contrast agent (DCA) and healthy rabbits with the contrast agent (NCA). In each group, 6 rabbits underwent IVIM and BOLD imaging at 1 hour, 1 day, 2 days, 3 days, and 4 days after an iohexol injection while 5 rabbits were selected to undergo blood and histological examinations at these specific time points. Iohexol was administrated at a dose of 2.5 g I/kg of body weight. Further, the apparent transverse relaxation rate (R2*), average pure molecular diffusion coefficient (D), pseudo-diffusion coefficient (D*), and perfusion fraction (f) were calculated.

RESULTS

The D and f values of the renal cortex (CO) and outer medulla (OM) were significantly decreased compared to baseline values in the 2 groups 1 day after the iohexol injection (p < 0.05). A marked reduction in the D* values for both the CO and OM was also observed after 1 hour in each group (p < 0.05). In the OM, a persistent elevation of the R2* was detected for 4 days in the DCA group (p < 0.05). Histopathological changes were prominent, and the pathological features of CI-AKI aggravated in the DCA group until day 4. The D, f, and R2* values significantly correlated with the histological damage scores, hypoxia-inducible transcription factor-1α expression scores, and serum creatinine levels.

CONCLUSION

A combination of IVIM and BOLD imaging may serve as a noninvasive method for detecting and monitoring CI-AKI in the early stages in the diabetic kidney.

Characterization of Polysaccharides Extracted from Sargassum fusiforme and Its Effective Prevention of Contrast-Induced Nephropathy via Enhancing Antioxidant Capacity

Contrast-induced nephropathy (CIN) is a common complication in patients with coronary arteriography, and oxidative stress is involved in the CIN pathogenesis. Sargassum fusiforme (SF) is a brown seaweed with medicinal value, and its polysaccharides have good antioxidant activity. In this study, the crude polysaccharides (cSFP-C) were extracted by cold water, precipitated by ethanol, purified by CaCl2, and detected with high contents of sulfate radical and fucose. cSFP-C is composed of glucose, glucuronic acid, xylose, rhamnose, mannose, galactose, and fucose with a molar ratio of 1.0 : 0.4 : 5.6 : 1.2 : 1.7 : 12.3 : 56.1. The cSFP-C has the typical absorption of polysaccharides. Antioxidation assays in vitro showed that cSFP-C exhibited superoxide radical scavenging activity which was better than the hot water-extracted crude polysaccharides (cSFP-H). 20 rats were divided into 4 groups (n=5): sham group; CIN group; CIN+cSFP-C group, and cSFP-C group. The CIN+cSFP-C group and cSFP-C group were pretreated intragastrically with cSFP-C at a dose of 9.45 g/kg twice daily for 5 consecutive days. Then, the CIN group and CIN+cSFP-C group were given indomethacin to develop CIN. The in vivo results showed that cSFP-C could decrease blood creatinine and urea nitrogen, inhibiting pathological injury in the renal tissues. The MDA content of renal tissues was decreased, while the activity of SOD was increased. The crude sulfated polysaccharides extracted from S. fusiforme have a renoprotective effect on oxidative stress to alleviate the kidney injury in CIN rats.

CHA2DS2-VASC Score Predicts Risk of Contrast-Induced Nephropathy in Non-ST Elevation Myocardial Infarction Patients Undergoing Percutaneous Coronary Interventions

BACKROUND

The CHA2DS2-VASC score, used for embolic risk stratification in atrial fibrillation, has been reported recently to predict adverse clinical outcomes in patients with coronary artery disease. We investigated the correlation between the CHA2DS2-VASC score and contrast-induced nephropathy (CIN) in patients with non-ST elevation myocardial infarction (NSTEMI) who underwent percutaneous coronary intervention (PCI).

METHODS

We retrospectively enrolled 363 (191; 52.6% men) NSTEMI patients undergoing PCI. The CHA2 DS2-VASC score was calculated for each patient, and the study population was divided into 2 groups: CHA2DS2-VASC score <2 group (low score; n = 259, 71.3%) and CHA2DS2-VASC score ≥2 group (high score; n = 104, 28.6%). Patients were then reallocated to 2 groups according to the presence or absence of CIN. CIN was defined as a rise in serum creatinine >0.5 mg/dL or >25% increase in baseline within 72 h after PCI.

RESULTS

Overall, 56 cases (15.4%) of CIN were diagnosed. When patients with a CHA2DS2-VASC score of <2 were compared with those with a CHA2DS2-VASC score of ≥2, patients with a high score had a higher frequency of CIN (33) 31.7% versus (23) 8.9%; p < 0.001. Also patients with CIN had higher CHADS2 VASC score (3.94 ± 1.13 vs. 1.68 ± 0.46, p < 0.001). Additionally, in-hospital mortality, length of hospital stay, major bleeding, requirement of mechanical ventilation, and dialysis were observed significantly higher in patients with CHA2DS2-VASC score of ≥2 (p = 0.001, p = 0.002, p = 0.006, p = 0.001, p = 0.001, respectively). In receiver operating characteristic curve analysis, the area under the curve for predicting CIN was 0.702 (p < 0.001, 95% CI 0.617-0.787) and cutoff value was 2.5 (sensitivity 58.9%, specificity 76.9%) for the number of CHA2DS2-VASC score.

CONCLUSION

In NSTEMI patients undergoing PCI, CHADS2 VASC score is associated with an increased risk for CIN and in-hospital morbidity and mortality.

Periprocedural myocardial and renal injury in patients undergoing elective percutaneous coronary interventions - is there an association?

Periprocedural myocardial injury (PMI) and contrast-induced nephropathy (CIN) are frequent complications of percutaneous coronary intervention (PCI) associated with early and late major adverse cardiovascular events. Both conditions are associated with similar risk factors, which could imply their possible association. The aim of our study was to assess the correlation of PMI and early postprocedural creatinine shift (ECS) as a marker of renal injury.A total of 209 hospitalized patients with stable coronary artery disease (CAD) were enrolled, who underwent an elective PCI in a period of 12 months. All patients had their serum high-sensitivity troponin I (hsTnI) measured at baseline and 16 hours after the PCI. PMI was defined according to the elevation of postprocedural hsTnI using criteria provided by both the most recent consensus documents as well as evidence-based data. Renal injury was evaluated using the ECS concept. Serum creatinine (SCr) was also measured at baseline and at 16 hours. ECS was defined as SCr >5% at 16 hours compared to baseline.Although incidence of both PMI (77.5%) and ECS (44.5%) were high, no association of these 2 conditions could be found. Further analyses of our data showed that diabetes is associated with a higher incidence of ECS, while patients on beta-blocker therapy had a lower incidence of ECS.In our study, no association between PMI and ECS was found. Additional studies with a larger number of patients and longer patient observation are needed to assess the correlation between PMI and CIN as well as to validate the attractive, but controversial, concept of ECS as an early marker of CIN.

CHA2DS2-VASc score as a novel predictor for contrast-induced nephropathy after percutaneous coronary intervention in acute coronary syndrome

Background

CHA2DS2-VASc score, used for atrial fibrillation to assess the risk of embolic complications, have shown to predict adverse clinical outcomes in acute coronary syndrome (ACS), irrespective of atrial fibrillation. This study envisaged to assess the predictive role of CHA2DS2-VASc score for contrast-induced nephropathy (CIN) in patients with ACS undergoing percutaneous coronary intervention (PCI).

Methods

A total of 300 consecutive patients with ACS undergoing PCI were enrolled in this study. CHA2DS2-VASc score was calculated for each patient. These patients were divided into two groups as Group 1 (with CIN) and Group 2 (without CIN). CIN was defined as increase in serum creatinine level ≥0.5 mg/dL or ≥25% increase from baseline within 48 h after PCI. After receiver operating characteristic curve analysis, the study population was again classified into two groups: CHA2DS2-VASc score ≤3 group (Group A) and score ≥4 group (Group B).

Results

CIN was reported in 41 patients (13.6%). Patients with CIN had a higher frequency of hypertension, diabetes mellitus, and had a lower left ventricular ejection fraction and baseline estimated glomerular filtration rate. Receiver operating characteristic curve analysis showed good predictive value of CHA2DS2-VASc score for CIN (area under the curve 0.81, 95% CI 0.73–0.90). Patients with a CHA2DS2-VASc score of ≥4 had a higher frequency of CIN as compared with patients with score ≤3 (56.8% vs 4.8%; p = 0.0001) with multivariate analysis demonstrating CHA2DS2-VASc score of ≥4 to be an independent predictor of CIN.

Conclusion

In patients with ACS undergoing PCI, CHA2DS2-VASc score can be used as a novel, simple, and a sensitive diagnostic tool for the prediction of CIN.

Contrast media (meglumine diatrizoate) aggravates renal inflammation, oxidative DNA damage and apoptosis in diabetic rats which is restored by sulforaphane through Nrf2/HO-1 reactivation

Diabetes mellitus is an independent risk factor for renal impairment in patients exposed to contrast media. It doubles the risk and decreases survival rate of contrast induced nephropathy (CIN). Sulforaphane has antioxidant properties via Nrf2 activation. The interaction of diabetes and/or sulforaphane with contrast media on Nrf2 regulation is not yet understood. Herein, diabetes was induced by a single intra-peritoneal injection of streptozotocin. Animals were then divided into five groups; control non-diabetic group; diabetic group; diabetic/sulforaphane group; diabetic/CIN group; diabetic/CIN/sulforaphane group. Animals were assessed 24 h after CIN induction. Sulforaphane improved the impaired nephrotoxicity parameters, histopathological features, and oxidative stress markers induced by contrast media (meglumine diatrizoate) in diabetic rats. Immunofluorescence detection revealed increased Nrf2 expression in kidney sections after sulforaphane pretreatment. Moreover, gene expression of Nrf2 and HO-1 were up-regulated, while IL-6 and caspase3 were down-regulated in kidney tissues of animals pretreated with sulforaphane. In NRK-52E cells, sulforaphane pretreatment significantly ameliorated the cytotoxicity of meglumine diatrizoate. However, silencing Nrf2 using small interfering RNA (siRNA) abolished the cytoprotective effects of sulforaphane. Collectively, the results of this study suggest that Nrf2/HO-1 pathway has a protective role against CIN and support the clinical implication of Nrf2 activators, such as sulforaphane, in CIN particularly in diabetic patients.

CHA2DS2-VASC score as a preprocedural predictor of contrast-induced nephropathy among patients with chronic total occlusion undergoing percutaneous coronary intervention: a single-center experience

Background

The usefulness of the CHA2DS2-VASC risk score (CVRS) in predicting the occurrence of contrast-induced nephropathy (CIN) among patients with chronic total occlusion (CTO) undergoing percutaneous coronary intervention (PCI) remains unclear.

Method

A total of 239 patients with CTO who underwent PCI were included in this study. They were divided into 3 groups according to the CVRS: low-risk group (1 point, n = 64), intermediate-risk group (2 points, n = 135), and high-risk group (≥3 points, n = 40). Baseline serum creatinine was determined upon admission before the procedure. The serum creatinine level was monitored for 72 h post-procedure to determine the occurrence of CIN.

Results

The total incidence of CIN in patients with CTO who underwent PCI was 16.3%. The average CVRS in the CIN group was significantly higher than that in the non-CIN group (3.1 ± 1.2 VS 2.1 ± 1.1, P < 0.001). The incidence of CIN in the high-risk group was 5.6 times higher than that in the low-risk group (37.5% VS 6.3%, P < 0.001). Similar to the Mehran risk score (AUC, 0.754; 95% CI, 0.698–0.810; P < 0.001), the receiver operating characteristic curve analysis showed a good diagnostic value of the CVRS in predicting CIN among patients with CTO who underwent interventional therapy for having CVRS≥3 (sensitivity, 69.2%; specificity, 78.0%; AUC, 0.742; 95% CI, 0.682–0.797; P < 0.001). The multivariate analysis showed that the higher pulse pressure and contrast volume, lower baseline glomerular filtration rate, and CVRS ≥3 were independent predictors of CIN.

Conclusions

The CVRS can be used as a simple pre-procedural predictor of CIN among patients with CTO undergoing PCI.

Why Have Detection, Understanding and Management of Kidney Hypoxic Injury Lagged Behind those for the Heart?

The outcome of patients with acute myocardial infarction (AMI) has dramatically improved over recent decades, thanks to early detection and prompt interventions to restore coronary blood flow. In contrast, the prognosis of patients with hypoxic acute kidney injury (AKI) remained unchanged over the years. Delayed diagnosis of AKI is a major reason for this discrepancy, reflecting the lack of symptoms and diagnostic tools indicating at real time altered renal microcirculation, oxygenation, functional derangement and tissue injury. New tools addressing these deficiencies, such as biomarkers of tissue damage are yet far less distinctive than myocardial biomarkers and advanced functional renal imaging technologies are non-available in the clinical practice. Moreover, our understanding of pathogenic mechanisms likely suffers from conceptual errors, generated by the extensive use of the wrong animal model, namely warm ischemia and reperfusion. This model parallels mechanistically type I AMI, which properly represents the rare conditions leading to renal infarcts, whereas common scenarios leading to hypoxic AKI parallel physiologically type II AMI, with tissue hypoxic damage generated by altered oxygen supply/demand equilibrium. Better understanding the pathogenesis of hypoxic AKI and its management requires a more extensive use of models of type II-rather than type I hypoxic AKI.

Does Resveratrol Play a Role in Decreasing the Inflammation Associated with Contrast Induced Nephropathy in Rat Model?

Contrast is widely used in invasive image examinations such as computed tomography (CT) and angiography; however, the risk of contrast-induced nephropathy (CIN) is high. The aim of this study was to investigate the protective effect of resveratrol in a rat model of CIN. Sprague-Dawley rats were divided into four groups: the control group (0.9% saline infusion only); resveratrol group (RSV, resveratrol, 30 mg/kg); contrast media group (CIN); and resveratrol + contrast media group (RCIN, resveratrol 30 mg/kg 60 min before CIN). CIN was induced via an intravenous injection of a single dose of indomethacin (10 mg/kg), one dose of N-nitro-L-arginine methyl ester (10 mg/kg), and a single dose of contrast medium iopromide (2 g/kg). Blood urea nitrogen, creatinine, and neutrophil gelatinase-associated lipocalin (NGAL) were higher in the CIN group compared to the other groups. Histopathological tubule injury scores were also higher in the CIN group compared to the other groups (p < 0.01). NLPR3 in kidney tissue were higher in the CIN group compared to the other groups; however, these results were improved by resveratrol in the RCIN group compared with the CIN group. The expressions of IL-1β and the percentage of apoptotic cells were higher in the CIN group than in the control and RSV groups, but they were lower in the RCIN group than in the CIN group. The expression of cleaved caspase-3 was higher in the CIN group than in the control and RSV groups, but lower in the RCIN group than in the CIN group. Resveratrol treatment attenuated both injury processes and apoptosis and inhibited the inflammasome pathway in this rat CIN model.