Alteration of autophagy-related protein 5 (ATG5) levels and Atg5 gene expression in diabetes mellitus with and without complications.

BACKGROUND: Autophagy is a catabolic mechanism that involves lysosomal-dependent degradation of unnecessary intracellular components and responsible for normal cellular homeostasis. Autophagy pathway and its key participant ATG5/LC3 are associated with several pathologies such as diabetes mellitus and its complications. METHODS: Levels and expression of autophagy key components ATG5 and LC3B were analyzed in both human model and murine tissues. One hundred and twenty human subjects were divided into four groups: Healthy (control), diabetes mellitus without complications, diabetic nephropathy, and diabetic retinopathy. Additionally, we used kidneys from WT healthy and diabetic nephropathy mice. Lysate derived from human peripheral blood mononuclear cells and murine renal cortex lysates were subjected to western blot and immunohistochemical analysis. RESULTS: Western blot and immunohistochemical analysis demonstrate that ATG5 protein levels were significantly decreased in diabetes mellitus, diabetic nephropathy (DN), and diabetic retinopathy patients versus healthy controls and in DN mice compared to healthy mice (0.65 ± 0.04; 1.15 ± 0.13 A.U. units, respectively). Quantification of staining area (%) of ATG5 mice tissue expression also decreased in DN versus healthy mice (4.42 ± 1.08%; 10.87 ± 1.01%, respectively). LC3B LEVELS AND EXPRESSION: Significant reduction in peripheral blood mononuclear cells in diabetic patients (with or without complications) vs. healthy controls. Renal LC3B levels were lower in DN versus healthy mice (0.36 ± 0.03; 0.68 ± 0.07 A.U. units). Renal LC3B staining quantification revealed significant reduction in DN versus healthy mice (1.7 ± 0.23%; 8.56 ± 1.7%). CONCLUSION: We conclude that ATG5, as well as LC3B, are down regulated in diabetic patients with or without complications. This diminution contributes to deficiencies in the autophagy process.

[AUTOPHAGY AND DIABETIC NEPHROPATHY].

INTRODUCTION: Diabetes mellitus (DM) is the leading cause of end stage renal disease; 40% of the patients worldwide will require replacement therapy after 20 years of DM. Early-stage diabetic nephropathy is characterized by hyper filtration with micro-and macro albuminuria. Later on end-stage renal disease (ESRD) can appear; 40% of diabetic patients develop micro-and macrovascular complications, with increased risk among patients with genetic predisposition, such as Haptoglobin 2-2 phenotype. The most frequent complications are diabetic kidney disease, diabetic retinopathy and coronary artery disease. Chronic systemic inflammation and the inflammatory response, such as increased circulating cytokines have been recognized as main players in the development and progression of diabetic nephropathy. DM is also associated with increased oxidative stress, and alterations in carbohydrate, lipid and protein metabolism. Blocking the renin- angiotensin- aldosterone system (RAAS) is not sufficient to delay the progression of DM. Autophagy may be involved in the pathogenesis of diabetic nephropathy. Under normal blood glucose level, autophagy is an important protective mechanism in renal epithelial cells, including podocytes, proximal tubular, mesangial and endothelial cells. Down regulation of the autophagy mechanism, as in hyperglycemic condition, can contribute to the development and progression of DM. The recently used new family of drugs SGL2Tis (sodium-glucose cotransporter-2 inhibitors) reduces the typical glomerular hyper-filtration. Preclinical and clinical studies focusing on SGLT2I treatment have consistently demonstrated a reduction in albuminuria and maintenance of renal function. SGLT2 inhibition may lead to positive molecular changes in podocyte cells and proximal tubule cells by directly affect basal autophagy.

The Therapeutic Effect of Active Vitamin D Supplementation in Preventing the Progression of Diabetic Nephropathy in a Diabetic Mouse Model.

BACKGROUND: Diabetic nephropathy (DN) is one of the most common microvascular complications of diabetes and is the leading cause of end-stage renal disease (ESRD) and replacement therapy worldwide. Vitamin D levels in DN patients are very low due to the decrease in the synthesis and activity of 1-α hydroxylase in the proximal tubule cells and decrease in the vitamin D receptor abundance. To date, few studies have shown the antioxidant effects of 1α,25-dihydroxyvitamin D3 [1,25(OH)2D3] on hyperglycemia-induced renal injury. The selective activator of the vitamin D receptor, paricalcitol, reduces proteinuria and slows the progression of kidney injury. The precise mechanism through which vitamin D affects diabetic status and provides kidney protection remains to be determined. METHODS: Diabetes mellitus (DM) was induced in 94 8-week-old DBA/2J mice by intraperitoneal injection of streptozotocin (STZ). DM mice were randomly divided into receiving vehicle or treatment with paricalcitol, the active vitamin D analog, 1 week after DM induction or paricalcitol treatment 3 weeks after DM induction. An additional control group of healthy wild-type mice was not treated. Urine albumin, blood urea nitrogen, and creatinine levels were measured before and at the end of the paricalcitol treatment. Periodic acid-Schiff, immunohistochemistry staining, and western blot of the renal tissues of vitamin D receptor, villin, nephrin, and podocin expressions, were analyzed. RESULTS: Paricalcitol treatment restored villin, nephrin, and podocin protein levels that were downregulated upon DM induction, and reduced fibronectin protein level. Vitamin D receptor activation by paricalcitol may reduce proteinuria of DN in mice and alleviate high-glucose-induced injury of kidney podocytes by regulating the key molecules such nephrin-podocin. CONCLUSIONS: Paricalcitol treatment was associated with improved structural changes in type 1 diabetic mice including upregulation of vitamin D receptor expression, and decreased fibrosis markers such as fibronectin. These effects may contribute to the consistent benefit of vitamin D analog to slow the deterioration in glomerular function and reduce the risk of ESRD in patients with type 1 and 2 diabetes mellitus. Our results suggest that additional use of paricalcitol may be beneficial in treating patients with diabetes under standard therapeutic strategies.

The Iron-Klotho-VDR Axis Is a Major Determinant of Proximal Convoluted Tubule Injury in Haptoglobin 2-2 Genotype Diabetic Nephropathy Patients and Mice.

The haptoglobin (Hp) genotype (1-1 and 2-2) is a major determinant of nephropathy progression in diabetes mellitus patients. Hp 2-2 diabetic mice have impaired Hb clearance and increased iron deposits and oxidative stress in the proximal tubules (PCT), leading to increased renal injury. However, the precise mechanism of the PCT injury in diabetic nephropathy (DN) remains elusive. In the kidney, 1,25(OH)2D3 suppresses the inflammatory response to renal tubular injury and requires normal renal expression of the α-klotho protein. In this study, we set out to test the hypothesis that the increased renal iron deposits in the PCT of Hp 2-2 DN affect the α-klotho-vitamin D receptor (VDR) axis and thereby exacerbates the PCT injury generated by the iron deposits. Immunohistochemical analysis of human and mouse kidney biopsies along with western blot analysis showed that the increased iron deposits in the PCT of the Hp 2-2 genotype were accompanied with significantly decreased α-klotho and VDR renal expression but significantly increased 1-α-hydroxylase renal expression. In conclusion, the iron-klotho-VDR axis is a major player in the mechanism contributing to iron-mediated PCT injury in diabetic Hp 2-2 mice and patients. Targeting this axis may open the way for new ideas regarding the pathogenesis and treatment of DN.

[HAPTOGLOBIN POLYMORPHISM AS AN INDEPENDENT PREDICTOR OF DIABETIC NEPHROPATHY AND RETINOPATHY].

INTRODUCTION: The antioxidant protein haptoglobin (Hp) plays a major role in the development of diabetic complications such as diabetic nephropathy and retinopathy. In humans, two alleles of Hp were identified: 1 and 2 with three possible genotypes: 1-1, 2-1, and 2-2. The Hp protein products differ in their biochemical and biophysical properties, such as their antioxidant capacity. The Hp1 protein is superior to the Hp2 protein in binding to free hemoglobin and neutralizing its oxidative potential and the accompanying renal and retinal injury. Hence, diabetic patients with different Hp phenotypes have variable susceptibility to developing diabetic nephropathy and retinopathy. In diabetes, the kidney and the retinal injury progress gradually over time. Thus, understanding the factors that mediate the aggravation and progression of these complications is of critical importance. One of the latest hypotheses regarding the involvement of haptoglobin in the development of diabetic complications is its contribution to impaired vitamin D activation in the kidney. Over the last few years, great efforts were made in the field to explore this notion and decrypt the mechanism behind it. The goal in this area is that the research findings will be translated into clinical practice and lead to the development of a pharmacogenomics clinical approach that will deal with diabetic complications by selective administration of vitamin D according to the Hp genotype.

Interaction between the Haptoglobin 2 Phenotype and Diabetes Mellitus on Systolic Pulmonary Arterial Pressure and Nitric Oxide Bioavailability in Hemodialysis Patients.

Elevated systolic pulmonary artery pressure (s-PAP, ≥35 mmHg) serves as an independent predictor of mortality in hemodialysis (HD) and diabetic (DM) patients. A polymorphism in the antioxidant Haptoglobin (Hp) gene has been shown to regulate the bioavailability of nitric oxide (NO), a major mediator of pulmonary vascular tone. We therefore set out to test the hypothesis that the Hp polymorphism may be a determinant of developing elevated s-PAP specifically in the DM state due to a decreased bioavailability of NO. To test our hypothesis we Hp typed and performed transthoracic echocardiography on a series of HD patients and stratified them into elevated and normal s-PAP groups and then evaluated whether there was a significant association between the Hp type, elevated s-PAP, and decreased NO bioavailability as defined by low plasma nitrite. We found a statistically significant interaction between the Hp type and DM on the prevalence of elevated s-PAP and lower mean nitrite levels with the combination of elevated s-PAP and low nitrite levels being significantly more prevalent in Hp 2-2 DM individuals. We conclude that the Hp 2 type is associated with elevated s-PAP levels and low plasma nitrite levels in HD patients specifically in the DM state.

A rare bacteremia caused by Cedecea davisae in patient with chronic renal disease.

PATIENT: Female, 77. FINAL DIAGNOSIS: Bacteremia. SYMPTOMS: Chills • diarrhea • fever • nausea. MEDICATION: - CLINICAL PROCEDURE: X-Ray • CBC • urine and blood cultur. SPECIALTY: Infectious diseases. OBJECTIVE: Rare disease. BACKGROUND: Cedecea davisae is a gram negative, oxidase negative bacilli that include 5 species. In the medical literature there are very few reports that describe infections caused by different species of the Cedecea genus. CASE REPORT: In this paper we report a fourth case of bacteremia in a 77 year-old patient with a chronic renal disease that was successfully treated with ceftazidim and ciprofloxacin. Additionally, we present a review of all the reported infections that were caused by C. davisae. CONCLUSIONS: Five cases (not including our report) of Cedecea bacteremia were reported so far. Cedecea infections and particularly C. davisae infections can be difficult to treat due to the antibiotic resistance of the bacterium. Therefore we propose to consider treating C. davisae bacteremia with a combined antibiotic treatment until getting laboratory results for antibiotic-sensitivity tests.

Esophageal varices: evaluation with esophagography with barium versus endoscopic gastroduodenoscopy in patients with compensated cirrhosis--blinded prospective study.

PURPOSE: To prospectively evaluate the accuracy of esophagography with barium in diagnosis of esophageal varices (EV) in patients with compensated cirrhosis, with endoscopic gastroduodenoscopy as the reference standard. MATERIALS AND METHODS: In this study, which was approved by the local Helsinki Committee and in which all patients consented to participate, 61 patients with cirrhosis (34 men, 27 women; mean age, 61 years; range, 36-76 years) received a diagnosis clinically or with liver biopsy. In 87% (n = 53) of patients, Child-Pugh classification was A; in 13% (n = 8), Child-Pugh classification was B. They were evaluated with endoscopic gastroduodenoscopy, according to Japanese general criteria. Esophagography was performed within 3 weeks of endoscopic gastroduodenoscopy, and EV were assigned grades as follows: 0, no EV were seen; 1, EV manifested as very mild irregularities of the folds; and 2, the irregularity of the folds (EV) was clearly present. They were also assigned grades for shape and size: grade F0, no EV detected; grade F1, small straight EV; grade F2, slightly enlarged tortuous EV occupying less than one-third of esophageal lumen; and grade F3, large coil-shaped EV that occupied more than one-third of esophageal lumen. The sensitivity and specificity and positive and negative predictive values of esophagography for identification of each grade of EV were calculated separately, as was the 95% confidence interval. RESULTS: All large EV (grades F2 and F3) were diagnosed at esophagography. Sensitivity declined with small EV (grade F1) to 71. The overall sensitivity of esophagography was 89% (95% confidence interval: 75.9%, 96.5%), the overall specificity was 83% (95% confidence interval: 64.5%, 94.7%), the overall positive predictive value was 89%, and the overall negative predictive value was 83% (95% confidence interval: 64.5%, 94.7%). Overall accuracy was 87%. CONCLUSION: Esophagography is highly accurate in diagnosis of EV and can be considered a viable noninvasive alternative for determination of patients who should be selected for prophylactic treatment.