Age-related oxidative decline of mitochondrial functions in rat brain is prevented by long term oral antioxidant supplementation

A combination of antioxidants (N-acetyl cysteine, α-lipoic acid, and α-tocopherol) was selected for long term oral supplementation study in rats for protective effects on age-related mitochondrial alterations in the brain. Four groups of rats were chosen: young control (6–7 months); aged rats (22–24 months); aged rats (22–24 months) on daily antioxidant supplementation from 18 month onwards and young rats (6–7 months) on daily antioxidant supplementation from 2 month onwards. The brain mitochondrial functional parameters, status of antioxidant enzymes and accumulation of oxidative damage markers were measured in the four groups of rats. A significant decrease in complex IV activity and a loss of transmembrane potential and phosphorylation capacity along with an increased accumulation of oxidative damage markers and compromised antioxidant enzyme status were noticed in aged rat brain mitochondria as compared to that in young controls, but in aged rats supplemented with oral antioxidants the mitochondrial alterations were largely prevented. Antioxidant supplementation in young rats had no effect on mitochondrial parameters investigated in this study. The results have implications in biochemical and functional deficits of brain during aging as well as in neurodegenerative disorders.     

Supplement Timing of Cranberry Extract Plays a Key Role in Promoting Caenorhabditis elegans Healthspan

Consumption of nutraceuticals is a major and potent dietary intervention for delaying aging. As the timing of administration is critical for the efficacy of bioactive compounds in medicine, the effectiveness of nutraceuticals may also be dramatically affected by the timing of supplementation. Cranberry exact (CBE), rich in polyphenols, is consumed as a nutraceutical, and possesses anti-aging properties. Here, we examined the influence of timing on the beneficial effects of CBE supplementation in C. elegans. The prolongevity effect of CBE in different aged worms, young adults, middle-age adults, and aged adults, was determined. Early-start intervention with CBE prolonged the remaining lifespan of worms of different ages more robustly than late-start intervention. The effectiveness of CBE on stress responses and physiological behaviors in different aged worms was also investigated. The early-start intervention prominently promoted motility and resistance to heat shocks and V. cholera infection, especially in aged worms. Together, these findings suggest that the timing of CBE supplementation critically influences its beneficial effects on C. elegans lifespan and healthspan. It is of interest to further investigate whether the similar results would occur in humans.     

An echo-cardiographic (M-mode & 2D) analysis of thalassaemia major

25 cases of thalassaemia major were studied by 2D and M-mode echocardiography. A significantly increased (p less than 0.001) mean value (100.8 +/- 27.37 msec, range 80 to 140 msec) of A2-E (early relaxation period) interval on M-mode was observed in thalassemia in comparison to mean level (82.6 +/- 5.7, range 60 to 100 msec) of control population. No significant differences were noted in FS % (fractional shortening) and EF% (ejection fraction) when compared to corresponding normal values respectively. Mean serum iron concentration (142.2 +/- 29.1 micrograms/dl, range 102 to 192 micrograms/dl) was significantly higher in thalassaemia as compared to normal population (mean 106.3 +/- 11.4 micrograms/dl, range 75 to 120 micrograms/dl). There was also a direct correlation between serum iron concentration and A2-E interval. 11 patients (44%) showed abnormal A2-E interval but only 3 patients (12%) showed abnormal percentage of FS and EF. It is therefore concluded that A2-E interval will help to detect early left ventricular dysfunction much before overt and irreversible heart failure becomes manifest and which will also help to optimise transfusion and chelation therapy.     

Wnt/beta-catenin signaling mediates oval cell response in rodents

Adult hepatic stem cells or oval cells are facultative stem cells in the liver that are activated during regeneration only during inhibition of innate hepatocyte proliferation. On the basis of its involvement in liver cancer, regeneration, and development, we investigated the role of the Wnt/beta-catenin pathway in oval cell response, which was initiated in male Fisher rats with 2-acetylaminofluorine and two-third partial hepatectomy (PHX). Extensive oval cell activation and proliferation were observed at 5 and 10 days post-PHX, as indicated by hematoxylin-eosin and proliferating cell nuclear antigen analysis. A noteworthy increase in total and active beta-catenin was observed at this time, which was localized to the oval cell cytoplasm and nuclei by immunohistochemistry and confirmed by double immunofluorescence. A concomitant increase in Wnt-1 in hepatocytes along with increased expression of Frizzled-2 in oval cells was observed. This paracrine mechanism coincided with a decrease in Wnt inhibitory factor-1 and glycogen synthase kinase-3beta down-regulation leading to beta-catenin stabilization. To strengthen its role, beta-catenin conditional knockout mice were treated with 3,5-diethoxycarbonyl-1,4-dihydrocollidine to induce oval cell activation. A dramatic decrease in the A6-positive oval cell numbers in the absence of beta-catenin demonstrated a critical role of beta-catenin in oval cell biology. CONCLUSION: The Wnt/beta-catenin pathway plays a key role in the normal activation and proliferation of adult hepatic stem cells.     

Role of Bile Acids in Liver Injury and Regeneration following Acetaminophen Overdose

Bile acids play a critical role in liver injury and regeneration, but their role in acetaminophen (APAP)–induced liver injury is not known. We tested the effect of bile acid modulation on APAP hepatotoxicity using C57BL/6 mice, which were fed a normal diet, a 2% cholestyramine (CSA)–containing diet for bile acid depletion, or a 0.2% cholic acid (CA)–containing diet for 1 week before treatment with 400 mg/kg APAP. CSA-mediated bile acid depletion resulted in significantly higher liver injury and delayed regeneration after APAP treatment. In contrast, 0.2% CA supplementation in the diet resulted in a moderate delay in progression of liver injury and significantly higher liver regeneration after APAP treatment. Either CSA-mediated bile acid depletion or CA supplementation did not affect hepatic CYP2E1 levels or glutathione depletion after APAP treatment. CSA-fed mice exhibited significantly higher activation of c-Jun N-terminal protein kinases and a significant decrease in intestinal fibroblast growth factor 15 mRNA after APAP treatment. In contrast, mice fed a 0.2% CA diet had significantly lower c-Jun N-terminal protein kinase activation and 12-fold higher fibroblast growth factor 15 mRNA in the intestines. Liver regeneration after APAP treatment was significantly faster in CA diet–fed mice after APAP administration secondary to rapid cyclin D1 induction. Taken together, these data indicate that bile acids play a critical role in both initiation and recovery of APAP-induced liver injury.Bile acids are versatile biological molecules that regulate energy homeostasis, activate nuclear receptors and cell signaling pathways, and control cell proliferation and inflammatory processes in the liver and gastrointestinal tract.^1,2 Bile acids maintain their own homeostasis by activating a complex signaling network involving hepatic and intestinal farnesoid X receptor (FXR), small heterodimer partner, and intestinal fibroblast growth factor (FGF) 15 (FGF19 in human) expression, culminating in inhibition of the primary bile acid–synthesizing enzyme, CYP7A1.^3–6 Although bile acids are potent signaling molecules at pathophysiological concentrations, they cause apoptosis, necrosis, and oxidative stress.^3,7–10 Bile acids have also been implicated in stimulation of liver regeneration.^11–14 Studies in recent years indicate that the bile acid–mediated gut-liver signaling axis may play a critical role in regulation of liver homeostasis.^6,15,16Acetaminophen (APAP) is the most commonly used analgesic and antipyretic agent.¹⁷ An overdose of APAP is the major cause of acute liver failure in the United States.^18,19 The mechanisms of APAP-induced liver injury and subsequent liver regeneration are the focus of intense investigation.^20–22 In an overdose situation, excess APAP is mainly metabolized by CYP2E1 to a reactive metabolite, N-acetyl-p-benzoquinone imine (NAPQI). In hepatocytes, conjugation of NAPQI to GSH is the key mechanism for detoxification of NAPQI. Once the GSH is depleted, NAPQI attacks cellular proteins, especially mitochondrial proteins, to form protein adducts. This triggers a cascade of intracellular signaling events involving c-Jun N-terminal protein kinase (JNK) activation and mitochondrial permeability transition, finally culminating in necrotic cell death.²⁰ Liver injury is followed by compensatory liver regeneration, which is a critical determinant of final outcome of liver injury.²³ Despite decades of research, how these intracellular events are affected by extracellular signaling is not known.The current study was designed to explore the role of bile acids in initiation of liver injury and stimulation of liver regeneration after APAP overdose. These studies are highly significant because the data reveal a novel role of bile acids in cellular protection and liver regeneration after APAP overdose, and these studies investigate the effect of resin-mediated bile acid depletion, a commonly used therapy, on APAP toxicity.     

Increased levels of interleukin-10 and IgG3 are hallmarks of Indian post-kala-azar dermal leishmaniasis

BACKGROUND: Post-kala-azar dermal leishmaniasis (PKDL), an established sequela of visceral leishmaniasis (VL), is proposed to facilitate anthroponotic transmission of VL, especially during interepidemic periods. Immunopathological mechanisms responsible for Indian PKDL are still poorly defined. METHODS: Our study attempted to characterize the immune profiles of patients with PKDL or VL relative to that of healthy control subjects by immunophenotyping, intracellular cytokine staining of peripheral blood mononuclear cells, and enzyme-linked immunosorbent assay for serum cytokines and immunoglobulin G (IgG) subclasses. RESULTS: Patients with PKDL had significantly raised percentages of peripheral CD3+CD8+ cells compared with control subjects, a difference that persisted after cure. Patients with PKDL showed an intact response to phytohemagglutinin, with the percentages of lymphocytes expressing interferon (IFN)-gamma, interleukin (IL)-2, IL-4, and IL-10 being comparable to those in control subjects. Patients with VL had decreased IFN-gamma and IL-2 expression, which was restored after cure, and increased IL-10 expression, which persisted after cure. In their response to Leishmania donovani antigen, patients with PKDL showed a 9.6-fold increase in the percentage of IL-10-expressing CD3+CD8+ lymphocytes compared with control subjects, and this percentage decreased with treatment. Patients with PKDL had raised levels of IgG3 and IgG1 (surrogate markers for IL-10), concomitant with increased serum levels of IL-10. CONCLUSIONS: IL-10-producing CD3+CD8+ lymphocytes are important protagonists in the immunopathogenesis of Indian PKDL.