TNF-α mediates increased susceptibility to ischemic AKI in diabetes

Preexisting Diabetes and Risks of Morbidity and Mortality After Gastrectomy for Gastric Cancer: A Nationwide Database Study

The purpose of this study was to determine the risk of surgical mortality and morbidity in patients with diabetes mellitus (DM) undergoing a gastrectomy for gastric cancer (GC). Using the Taiwan National Health Insurance Research Database, we identified 6284 patients who underwent gastrectomy for GC from 1999 to 2010. In addition, we created a non-DM control cohort consisting of 6268 patients who received gastrectomy during the same period. Compared with the non-DM cohort, the DM cohort exhibited a higher prevalence of preoperative coexisting medical conditions, namely hypertension, hyperlipidemia, coronary artery disease, chronic kidney disease, chronic pulmonary disease, stroke, and cirrhosis. The odds ratio (OR) of 30-day postoperative mortality after gastrectomy in the DM cohort was 1.04 (95% confidence interval 0.78-1.40) after we adjusted for covariates. The DM cohort did not exhibit a significantly higher risk of 30-day postoperative morbidities. Further analysis revealed that only patients with a history of a DM-related coma exhibited a higher risk of 30-day postoperative mortality (adjusted OR 2.46, 95% confidence interval 1.10 - 5.54). Moreover, the risk of 90-day postoperative mortality was significantly higher in patients with DM-related eye involvement, coma, peripheral circulatory disease, and renal manifestations, in comparison with the non-DM cohort. The risk of 90-day mortality after gastrectomy for GC is higher in patients with DM-related manifestations than those without DM.

Pre-existing diabetes and risks of morbidity and mortality after liver transplantation: A nationwide database study in an Asian population

BACKGROUND

Whether diabetes mellitus (DM) is associated with a higher risk of perioperative mortality and mortality after liver transplantation (LTx) remains unclear.

METHODS

We compared the risk of postoperative mortality and morbidity in DM and non-DM patients undergoing LTx. We enrolled 558 DM patients who underwent LTx from 2000 to 2010.

RESULTS

DM was associated with elevated 90-day risk of post-LTx stroke. Otherwise, the DM cohort did not exhibit significantly higher risks of postoperative morbidities, such as septicemia, pneumonia, and wound infection, than the non-DM cohort. Cox proportional hazards regression model showed that patients with DM with coexisting renal manifestations were at a significantly high risk of 30-day and 90-day postoperative mortality. Further comorbidity stratification analysis showed that DM cohort exhibited higher risk of mortality than the non-DM cohort if the patients had liver cancer, or did not have hypertension, ischemic heart disease, and chronic obstructive pulmonary disease.

CONCLUSION

DM is associated with elevated risk of 90-day post-LTx. Moreover, DM patients with coexisting renal manifestations exhibited an increased postoperative risk of mortality after LTx.

Effects of Tumor Necrosis Factor-α on Podocyte Expression of Monocyte Chemoattractant Protein-1 and in Diabetic Nephropathy

Background/Aims

Tumor necrosis factor (TNF)-α is believed to play a role in diabetic kidney disease. This study explores the specific effects of TNF-α with regard to nephropathy-relevant parameters in the podocyte.

Methods

Cultured mouse podocytes were treated with recombinant TNF-α and assayed for production of monocyte chemoattractant protein-1 (MCP-1) by enzyme-linked immunosorbent assay (ELISA). TNF-α signaling of MCP-1 was elucidated by antibodies against TNF receptor (TNFR) 1 or TNFR2 or inhibitors of nuclear factor-kappaB (NF-κB), phosphatidylinositol 3-kinase (PI3K) or Akt. In vivo studies were done on male db/m and type 2 diabetic db/db mice. Levels of TNF-α and MCP-1 were measured by RT-qPCR and ELISA in the urine, kidney and plasma of the two cohorts and correlated with albuminuria.

Results

Podocytes treated with TNF-α showed a robust increase (∼900%) in the secretion of MCP-1, induced in a dose- and time-dependent manner. Signaling of MCP-1 expression occurred through TNFR2, which was inducible by TNF-α ligand, but did not depend on TNFR1. TNF-α then proceeded via the NF-κB and the PI3K/Akt systems, based on the effectiveness of the inhibitors of those pathways. For in vivo relevance to diabetic kidney disease, TNF-α and MCP-1 levels were found to be elevated in the urine of db/db mice but not in the plasma.

Conclusion

TNF-α potently stimulates podocytes to produce MCP-1, utilizing the TNFR2 receptor and the NF-κB and PI3K/Akt pathways. Both TNF-α and MCP-1 levels were increased in the urine of diabetic db/db mice, correlating with the severity of diabetic albuminuria.

Resveratrol increases nephrin and podocin expression and alleviates renal damage in rats fed a high-fat diet

Resveratrol is well known for its anti-inflammation and anti-oxidant properties, and has been shown to be effective in alleviating the development of obesity. The purpose of this investigation was to analyze the effect of resveratrol on renal damage in obese rats induced by a high-fat diet (HFD) and its possible mechanisms. Male Sprague-Dawley rats were divided into three groups: control, HFD, and HFD plus resveratrol (treated with 100 mg/kg/day resveratrol). Body weight, serum and urine metabolic parameters, and kidney histology were measured. Meanwhile, the activities of nuclear factor-κB (NF-κB) and superoxide dismutase (SOD), the content of malondialdehyde (MDA), and the protein levels of tumor necrosis factor (TNF-α), monocyte chemotactic protein-1 (MCP-1), nephrin and podocin in kidney were detected. Our work showed that resveratrol alleviated dyslipidemia and renal damage induced by HFD, decreased MDA level and increased SOD activity. Furthermore, the elevated NF-κB activity, increased TNF-α and MCP-1 levels, and reduced expressions of nephrin and podocin induced by HFD were significantly reversed by resveratrol. These results suggest resveratrol could ameliorate renal injury in rats fed a HFD, and the mechanisms are associated with suppressing oxidative stress and NF-κB signaling pathway that in turn up-regulate nephrin and podocin protein expression.

Hyperglycemia, p53, and mitochondrial pathway of apoptosis are involved in the susceptibility of diabetic models to ischemic acute kidney injury

Patients with chronic kidney diseases, including diabetic nephropathy, are more susceptible to acute kidney injury (AKI) and have a worse prognosis following AKI. However, the underlying mechanism is unclear. Here we tested whether diabetic mice were more sensitive to AKI and show that renal ischemia-reperfusion induced significantly more severe AKI and higher mortality in the streptozotocin and the Akita diabetic mouse models. The severity of AKI in the mice correlated with their blood glucose levels. In vitro, high glucose-conditioned renal proximal tubular cells showed higher apoptosis and caspase activation following ATP-depletion and hypoxic injury, accompanied by a heightened mitochondrial accumulation of Bax and release of cytochrome c. In response to injury, both glucose-conditioned renal proximal tubular cells and diabetic kidney tissues showed markedly higher p53 induction. Suppression of p53 diminished the sensitivity of high glucose-conditioned cells to acute injury in vitro. Moreover, blockade of p53 by pifithrin-α, siRNA, or proximal tubule-targeted gene ablation reduced ischemic AKI in diabetic mice. Insulin reduced blood glucose in diabetic mice and largely attenuated their AKI sensitivity. Thus, our results suggest the involvement of hyperglycemia, p53 and mitochondrial pathway of apoptosis in the susceptibility of diabetic models to AKI.

Diabetes mellitus and increased postoperative risk of acute renal failure after hepatectomy for hepatocellular carcinoma: a nationwide population-based study

BACKGROUND

This study aimed to determine the effects of diabetes mellitus (DM) on the risk of surgical mortality and morbidity in patients undergoing hepatectomy for hepatocellular carcinoma (HCC).

METHODS

We identified 2,962 DM patients who underwent a hepatectomy for HCC from 2000 to 2010. The non-DM control cohort consisted of 2,962 patients who also received a hepatectomy during the same period. Age, sex, comorbidities, and year of admission were all matched between the 2 cohorts.

RESULTS

The prevalence of preoperative coexisting medical conditions was comparable between the DM and non-DM cohorts, except the percentage of patients undergoing major hepatectomy (lobectomy; 18.1 % in the DM cohort vs. 20.4 % in the non-DM cohort; p = 0.02).The hazard ratio (HR) of 30-day postoperative mortality in the DM patients after hepatectomy was 1.17 [95 % confidence interval (CI) 0.75-1.84] after adjustment. The DM cohort exhibited a significantly higher risk of postoperative septicemia (adjusted hazard ratio, 1.45; 95 % CI 1.06-2.00) and acute renal failure (adjusted hazard ratio, 1.70; 95 % CI 1.01-2.84) compared with that of the non-DM cohort, but this higher risk was not associated with the increased risk of other major morbidities, including pneumonia, stroke, and myocardial infarction. Further analysis showed that major hepatectomy (lobectomy) in DM patients carried higher risks of septicemia and acute renal failure. In multiple regression models, preoperative diabetes-related comorbidities were not significantly associated with 30-day postoperative mortality.

CONCLUSIONS

DM is associated with a significantly high risk of septicemia and acute renal failure, but not with other major complications or mortality, after hepatectomy for HCC.