Preconditioning with Triiodothyronine Improves the Clinical Signs and Acute Tubular Necrosis Induced by Ischemia/Reperfusion in Rats.

BACKGROUND Renal ischemia/reperfusion (I/R) injury is manifested by acute renal failure (ARF) and acute tubular necrosis (ATN). The aim of this study was to evaluate the effectiveness of preconditioning with 3, 3, 5 triiodothyronine (T3) to prevent I/R renal injury. METHODOLOGY/PRINCIPAL FINDINGS THE RATS WERE DIVIDED INTO FOUR GROUPS: sham-operated, placebo-treated (SO-P), sham-operated T3- treated (SO- T3), I/R-injured placebo-treated (IR-P), and I/R-injured T3-treated (IR- T3) groups. At 24 h before ischemia, the animals received a single dose of T3 (100 μg/kg). Renal function and plasma, urinary, and tissue variables were studied at 4, 24, and 48 h of reperfusion, including biochemical, oxidative stress, and inflammation variables, PARP-1 immunohistochemical expression, and ATN morphology. In comparison to the SO groups, the IR-P groups had higher plasma urea and creatinine levels and greater proteinuria (at all reperfusion times) and also showed: increased oxidative stress-related plasma, urinary, and tissue variables; higher plasma levels of IL6 (proinflammatory cytokine); increased glomerular and tubular nuclear PARP-1 expression; and a greater degree of ATN. The IR-T3 group showed a marked reduction in all of these variables, especially at 48 h of reperfusion. No significant differences were observed between SO-P and SO-T3 groups. CONCLUSIONS This study demonstrates that preconditioning rats with a single dose of T3 improves the clinical signs and ATN of renal I/R injury. These beneficial effects are accompanied by reductions in oxidative stress, inflammation, and renal PARP-1 expression, indicating that this sequence of factors plays an important role in the ATN induced by I/R injury.

Assay for high glucose-mediated islet cell sensitization to apoptosis induced by streptozotocin and cytokines

Pancreatic beta-cell apoptosis is known to participate in the beta-cell destruction process that occurs in diabetes. It has been described that high glucose level induces a hyperfunctional status which could provoke apoptosis. This phenomenon is known as glucotoxicity and has been proposed that it can play a role in type 1 diabetes mellitus pathogenesis. In this study we develop an experimental design to sensitize pancreatic islet cells by high glucose to streptozotocin (STZ) and proinflammatory cytokines [interleukin (IL)-1beta, tumor necrosis factor (TNF)-alpha and interferon (IFN)-gamma]-induced apoptosis. This method is appropriate for subsequent quantification of apoptotic islet cells stained with Tdt-mediated dUTP Nick-End Labeling (TUNEL) and protein expression assays by Western Blotting (WB).

The use of liver biopsy evaluation in discrimination of idiopathic autoimmune hepatitis versus drug-induced liver injury.

Distinguishing drug-induced liver injury (DILI) from idiopathic autoimmune hepatitis (AIH) can be challenging. We performed a standardized histologic evaluation to explore potential hallmarks to differentiate AIH versus DILI. Biopsies from patients with clinically well-characterized DILI [n = 35, including 19 hepatocellular injury (HC) and 16 cholestatic/mixed injury (CS)] and AIH (n = 28) were evaluated for Ishak scores, prominent inflammatory cell types in portal and intra-acinar areas, the presence or absence of emperipolesis, rosette formation, and cholestasis in a blinded fashion by four experienced hepatopathologists. Histologic diagnosis was concordant with clinical diagnosis in 65% of cases; but agreement on final diagnosis among the four pathologists was complete in only 46% of cases. Interface hepatitis, focal necrosis, and portal inflammation were present in all evaluated cases, but were more severe in AIH (P < 0.05) than DILI (HC). Portal and intra-acinar plasma cells, rosette formation, and emperiopolesis were features that favored AIH (P < 0.02). A model combining portal inflammation, portal plasma cells, intra-acinar lymphocytes and eosinophils, rosette formation, and canalicular cholestasis yielded an area under the receiver operating characteristic curve (AUROC) of 0.90 in predicting DILI (HC) versus AIH. All Ishak inflammation scores were more severe in AIH than DILI (CS) (P ≤ 0.05). The four AIH-favoring features listed above were consistently more prevalent in AIH, whereas portal neutrophils and intracellular (hepatocellular) cholestasis were more prevalent in DILI (CS) (P < 0.02). The combination of portal inflammation, fibrosis, portal neutrophils and plasma cells, and intracellular (hepatocellular) cholestasis yielded an AUC of 0.91 in predicting DILI (CS) versus AIH. Conclusion: Although an overlap of histologic findings exists for AIH and DILI, sufficient differences exist so that pathologists can use the pattern of injury to suggest the correct diagnosis.

The rise of soluble TWEAK levels in severely obese subjects after bariatric surgery may affect adipocyte-cytokine production induced by TNFα.

CONTEXT Soluble TNF-like weak inducer of apoptosis (sTWEAK) is generated by the intracellular proteolytic cleavage of full-length membrane-bound TNF-like weak inducer of apoptosis (mTWEAK). sTWEAK levels are reduced in diseases with an inflammatory component. Additionally, sTWEAK hampers TNFα activity in human cells. OBJECTIVES The objectives of the study were as follows: 1) to determine circulating sTWEAK in severe obesity and after bariatric surgery; 2) to study m/sTWEAK and its receptor fibroblast growth factor-inducible 14 (Fn14) protein expression in sc adipose tissue (SAT) of severely obese subjects, in SAT stromal vascular fraction (SVF), and isolated adipocytes and in human monocyte-derived macrophages; and 3) to explore, on human adipocytes, the sTWEAK effect on TNFα proinflammatory activity. DESIGN sTWEAK levels were measured in cohort 1: severely obese subjects (n = 23) and a control group (n = 35); and in cohort 2: (n = 23) severely obese subjects before and after surgery. The m/sTWEAK and Fn14 expressions were determined in SAT biopsies, SVF, and isolated adipocytes from severely obese and control subjects and in human monocyte-derived macrophages. In human primary cultured adipocytes, sTWEAK pretreated and TNFα challenged, IL-6, IL-8, and adiponectin protein and gene expressions were determined and nuclear factor-κ B and MAPK signaling analyzed. RESULTS sTWEAK levels were reduced in severely obese subjects. After surgery, sTWEAK levels rose in 69% of patients. mTWEAK protein expression was increased in SAT and SVF of severely obese subjects, whereas Fn14 was up-regulated in isolated adipocytes. M2 human monocyte-derived macrophages overexpress mTWEAK. In human adipocytes, sTWEAK down-regulates TNFα cytokine production by hampering TNFα intracellular signaling events. CONCLUSION The decrease of sTWEAK in severely obese patients may favor the proinflammatory activity elicited by TNFα.