Chandan K Sen

Indiana University School of Medicine | IUSOM · Department of Surgery

Progress in genome sciences has led to the development of sensitive and rapid techniques for DNA sequencing. These techniques, combined with improved application of the techniques for total RNA and mRNA isolations, amplification of DNA fragments by polymerase chain reaction (PCR), and the techniques for comprehensive analysis of transcription produ...

This chapter discusses the determination of oxidized and reduced lipoic acid using high-performance liquid chromatography (HPLC) and coulometric detection. α-lipoic acid has generated considerable clinical interest as a cellular thiol-replenishing and redox-modulating agent. Biologically, lipoate (LA) exists as lipoamide in at least five proteins w...

Several biochemical techniques are based on chromatography or electrophoresis for the determination of thiols from biological samples. These techniques are indispensable for the accurate and sensitive detection of specific thiols. Flow cytometric determination of cellular thiols is a powerful technique that is perhaps best suited for clinical appli...

In human cells, alpha-lipoic acid (LA) is present in a bound lipoyllysine form in mitochondrial proteins that play a central role in oxidative metabolism. The possible effects of oral LA supplementation, a single bout of strenuous exercise and endurance exercise training on the lipoyllysine content in skeletal muscle and liver tissues of rat were e...

The protective effects of anethole dithiolethione (ADT) against H2O2- or 4-hydroxynonenal (HNE)-induced cytotoxicity in human Jurkat T cells were investigated. Jurkat T cells were pretreated with ADT (10-50 microM) for 18 hr and then challenged with H202 or HNE for up to 4 hr. Cytotoxicity was assessed by measuring: 1) leakage of lactate dehydrogen...

Regulation of adhesion molecule expression and function by reactive oxygen species via specific redox sensitive mechanisms have been reported. The effects of clinically safe antioxidants in the regulation of adhesion molecule expression in human endothelial cells (ECV), and adherence of human Jurkat T cells to ECV cells were investigated. The thiol...

Oxidation-reduction (redox) based regulation of signal transduction and gene expression is emerging as a fundamental regulatory mechanism in cell biology. Electron flow through side chain functional CH2-SH groups of conserved cysteinyl residues in proteins account for their redox-sensing properties. Because in most intracellular proteins thiol grou...

α-Lipoic acid (LA) is taken up by cells and reduced to its potent dithiol form, dihydrolipoate(DHLA), much of which is rapidly effluxed out from cells. To improve retention in cells, the LA molecule was modified to confer a positive charge at physiological pH. N,N-dimethyl,N′-2-amidoethyl-lipoate was synthesized. The protonated form of the new mole...

Glutathione (GSH) is a low-molecular-weight thiol that is redox active and mostly present in mM concentrations in mammalian cells. High activity of GSH-dependent enzymes and remarkable GSH synthesizing ability of the skeletal muscle suggest that this tissue is a significant component of the complex inter-organ GSH homoeostasis. The hypothesis that...

While oxygen is vital to the existence of all aerobic organisms, under certain circumstances it forms reactive species and derivative oxidants that are noxious to biological molecules. However, nature has developed a coordinated antioxidant defence system against such oxidants. An imbalance between oxidant insult and antioxidant defences in favor o...

Skeletal muscle consumes significant amounts of oxygen, and its oxygen flux increases significantly under conditions of exercise and muscle contraction. This makes the muscle vulnerable to oxidative stress since concomitantly with the increase of oxygen flow there is an increase of free oxygen radicals which are a byproduct of muscle respiration. A...

Glutathione (GSH) has emerged to be one of the most fascinating endogenous molecules virtually present in all animal cells often in quite high (mM) concentrations. In addition to the detoxicant, antioxidant, and cysteine-reservoir functions of cellular glutathione, the potential of this ubiquitous thiol to modulate cellular signal transduction proc...

In many cell lines, glutamate cytotoxicity is known to be medicated by an inhibition of cystine transport. Because glutamate and cystine share the same transporter, elevated levels of extracellular glutamate competitively inhibit cystine transport leading to depletion of intracellular glutathione. A glutathione-depleted state impairs cellular antio...

Impaired antioxidant defences may predispose to the increased resting and exercise-induced oxidative stress found in patients with insulin-dependent diabetes mellitus (IDDM). We investigated major erythrocyte antioxidant enzyme activities at rest and in response to sustained, moderate intensity physical exercise in young diabetic men (n = 9) previo...

Monochloramine derivatives are long lived physiological oxidants produced by neutrophils during the respiratory burst. The effects of chemically prepared monochloramine (NH2Cl) on protein kinase C (PKC) and PKC-mediated cellular responses were studied in elicited rat peritoneal neutrophils and human Jurkat T cells. Neutrophils pretreated with NH2Cl...

Intraperitoneal injection of glutathione (GSH) is shown to effectively increase tissue glutathione content in two teleost species, the rainbow trout and the American eel. GSH uptake into teleost tissues is a distinct piscine feature of GSH biochemistry compared with mammalian species where little or not uptake occurs of exogenously added GSH. Enhan...

We observed that glutathione (GSH) status regulates the Ah receptor inducible cytochrome P4501A (CYP1A) gene expression and catalytic activity in 3,3',4,4'-tetrachlorobiphenyl (TCB) exposed rainbow trout. Tissue GSH status of TCB (1 mg/kg body weight, in corn oil) injected fish was manipulated by a) injecting (i.p.) GSH (0.25 g/kg), b) arresting GS...

Fish oil supplementation and physical exercise may induce oxidative stress. We tested the effects of 8 wk of alpha-tocopherol (vitamin E) and fish oil (FO) supplementation on resting and exercise-induced oxidative stress. Rats (n = 80) were divided into groups supplemented with FO, FO and vitamin E (FOVE), soy oil (SO), and SO and vitamin E (SOVE),...

TNFα is implicated in several skeletal muscle pathologies including muscle wasting of cachexia. Muscle wasting and other conditions such as physical exercise and immobilization are also associated with disturbances in muscle glutathione status. Hence, it was of interest to investigate the role of endogenous glutathione status in TNFα induced NF-κB...

The therapeutic potential of α-lipoic acid (thioctic acid) was evaluated with respect to its influence on cellular reducing equivalent homeostasis. The requirement of NADH and NADPH as cofactors in the cellular reduction of α-lipoic acid to dihydrolipoate has been reported in various cells and tissues. However, there is no direct evidence describin...

This chapter discusses the metabolic role and antioxidant properties of α-lipoate and its reduced form, dihydrolipoate and the effects of this antioxidant in modulating the redox-sensitive transcription factor nuclear factor KB (NF-κB). Because NF- κB is involved in a wide variety of acute inflammatory responses, and other aspects of rapid response...

Modulation of cellular thiols is an effective therapeutic strategy, particularly in the treatment of AIDS. Lipoic acid, a metabolic antioxidant, functions as a redox modulator and has proven clinically beneficial effects. It is also used as a dietary supplement. We utilized the specific capabilities of N-ethylmaleimide to block total cellular thiol...

The therapeutic potential of α-lipoic acid (thioctic acid) was evaluated with respect to its influence on cellular reducing equivalent homeostasis. The requirement of NADH and NADPH as cofactors in the cellular reduction of α-lipoic acid to dihydrolipoate has been reported in various cells and tissues. However, there is no direct evidence describin...

Lipoic acid (thiotic acid) is being used as a dietary supplement, and as a therapeutic agent, and is reported to have beneficial effects in disorders associated with oxidative stress, but its mechanism of action remains unclear. We present evidence that lipoic acid induces a substantial increase in cellular reduced glutathione in cultured human Jur...

The aim of these experiments was to determine the effects of combining high levels of vitamin E and lipoic acid supplementation on myocardial performance and arrhythmias during in vivo ischemia and reperfusion (I-R). Female Sprague-Dawley rats (4 months old) were randomly assigned to either a control diet group or a vitamin E and lipoic acid supple...

Although endurance training enhances the antioxidant defence of different tissues, information on the effect of sprint training is scanty. We examined the effect of sprint training on rat skeletal muscle and heart antioxidant defences. Male Wistar rats, 16-17 weeks old, were sprint trained on a treadmill for 6 weeks. Total glutathione levels and ac...

Reduced glutathione (GSH) plays a central role in maintaining an effective synergism between various physiological and exogenous antioxidants. We tested the effects of GSH andN-acetylcysteine (NAC, a pro-GSH clinical drug), intraperitoneal (i.p.) supplementation and GSH deficiency on exercise-induced leucocyte margination and neutrophil oxidative b...

The purpose of the present study was to investigate the effect of a single bout of exercise on the capillary growth in an in vitro angiogenesis model and its mechanism. The exercised rats were made to run continuously for 90 min at 20 m/min (0° incline) on a rodent treadmill just before sacrifice. First, we investigated the effect of soleus extract...

To assess the effect of acute physical exercise on oxidative stress and glutathione redox status and the relation to physical fitness in otherwise healthy young men with IDDM. Nine men with IDDM (HbA1 7.3 +/- 1.7%), ages 21-30 years, and 13 matched control subjects exercised on a bicycle ergometer for 40 min at 60% of their maximal oxygen consumpti...

The cytochrome P450 and the glutathione systems are two major pathways of xenobiotic metabolism. We tested the effect of hepatic glutathione content on P450 CYP1A1/2 induction by 3,3',4,4'-tetrachlorobiphenyl in rainbow trout (Oncorhynchus mykiss). Hepatic glutathione status of tetrachlorobiphenyl injected fish could be successfully manipulated by...

Reactive oxygen species (ROS) are implicated in the pathogenesis of a wide variety of human diseases. Recent evidence suggests that at moderately high concentrations, certain forms of ROS such as H202 may act as signal transduction messengers. To develop a better understanding of the exact mechanisms that underlie ROS-dependent disorders in biologi...

The accumulation of polycyclic aromatic hydrocarbons (PAHs) and responses of antioxidant enzymes were studied in an aquatic moss, Fontinalis antipyretica (Hedw.) transplanted around a city harbor. Glass fiber bags containing Fontinalis antipyretica (‘moss bags’) were transplanted at five sites on Lake Kallavesi of Finland in summer. Three sites wer...

In human Jurkat T cells and its subclone Wurzburg cells oxidant challenge elevated [Ca2+]i by mobilizing Ca2+ from intracellular stores. In Jurkat cells this effect was rapid and transient, but in Wurzburg cells the response was slow and sustained. H2O2-induced NF-kappaB activation in Wurzburg cells was not influenced by the presence of extracellul...

Reduced glutathione (GSH) plays a central role in maintaining an effective synergism between various physiological and exogenous antioxidants. We tested the effects of GSH and N-acetylcysteine (NAC, a pro-GSH clinical drug), intraperitoneal (i.p.) supplementation and GSH deficiency on exercise-induced leucocyte margination and neutrophil oxidative...

Nuclear factor (NF)-κB is a redox sensitive cytosolic transcription factor. Redox regulation of NF-κB has been implicated in the activation of the human immuno-deficiency virus (HIV). Therefore, inhibition of NF-κB activation may be an effective strategy for acquired immunodeficiency syndrome therapy. Anetholdithiolthione (ADT, 5-[p-methoxyphenyl]-...

There is consistent evidence from human and animal studies that strenuous physical exercise may induce a state wherein the antioxidant defenses of several tissues are overwhelmed by excess reactive oxygen. A wide variety of physiological and dietary antioxidants act in concert to evade such a stress. Submaximal long-duration exercise training may a...

The effect of strenuous aerobic exercise on the liberation of reactive oxygen species production by human granulocytes was investigated in 9 untrained healthy men. The influence of supplementation with N-acetylcysteine, a pro-glutathione free radical scavenger, on this was also investigated. Subjects performed two identical maximal exercise tests (...

Although the use of oxygen as metabolic fuel allows an attractive harvest of energy rich phosphates per molecule of glucose, a significant fraction of oxygen utilized by the body incompletely reduced and is known to be toxic. Such partially reduced forms of oxygen and some of their derivatives are highly reactive pro-oxidants that are collectively...

Strenuous physical exercise causes a remarkable perturbation of K+ homeostasis in skeletal muscle tissue. Potassium efflux is crucial for a number of physiological control processes; however, exercise-induced perturbation of K+ homeostasis in skeletal muscle is suggested to be implicated in the generation of muscle fatigue. Physical exercise is als...

To clarify the relative participation of particular ion transport systems in net univalent cation fluxes under basal conditions and altered volume of skeletal muscle-derived cells, the effect of inhibitors of the Na(+)-K+ pump (ouabain), univalent ion cotransporters [bumetanide, furosemide, and (dihydroindenyl)oxy alkanoic acid], and N+/H+ exchange...

Glutathione (GSH) plays a central role in coordinating the synergism between different lipid- and aqueous-phase antioxidants. We documented 1) how exogenous GSH and N-acetylcysteine (NAC) may affect exhaustive exercise-induced changes in tissue GSH status, lipid peroxides [thiobarbituric acid-reactive substances (TBARS)], and endurance and 2) the r...

Superoxide dismutases (SOD) are physiological antioxidant proteins which scavenge superoxides, a reactive oxygen species capable of producing diverse pathophysiological consequences. Mangano-SOD (Mn-SOD) is a mitochondrial enzyme. Our study presents the first evidence that a single bout of exhaustive exercise (EE) is associated with an increase in...

The exposure-effect relationship of benzo(a)anthracene (BaA) and benzo(a)pyrene (BaP), two potential environmental carcinogens, were evaluated in aquatic plants. The relationship was studied simultaneously by determining the BaA and BaP uptake/elimination and the responses of biotransformation and antioxidant enzymes to such exposures in the aquati...

The association between exercise intensity and related oxidative stress was investigated in nine men who exercised for 30 min at their aerobic (AeT) and anaerobic (AnaeT) thresholds. We also tested the effect of oral N-acetylcysteine (NAC) on exercise-associated rapid blood glutathione (GSH) oxidation in subjects performing two identical maximal bi...

Hatchery-reared immature rainbow trout (Oncorhynchus mykiss) were exposed to different concentrations (2 and 4 liters) of contaminated sediment taken from a site receiving unbleached pulp mill effluents. The fish were held in aquaria and sampled three times during an experimental period of 21 days. The monooxygenase activity, measured as the deethy...

Skeletal muscle derived L6 myoblasts possess a considerably high resting total glutathione (TGSH) pool. Exposure to L-buthionine-[S,R]-sulphoximine resulted in a 90% depletion of the intracellular TGSH pool. All the key enzymes of glutathione metabolism, especially glutathione S-transferase, were observed to be considerably active in the undifferen...

Preincubation of rat skeletal muscle derived L6 myoblasts with 10 mM NaF increased, the activity of Na+/H+ exchanger, and the uptake of 45Ca by 2 and 5 folds, respectively. In cultured vascular smooth muscle cells (CVSMC) of rat aorta, NaF increased the activity of Na+,K(+)-pump, Na+/H+ exchanger, passive permeability for Na+, and 45Ca uptake by 1....

Female beagle dogs were treadmill trained 40 km/day at 5.5-6.8 km/h, 15% upgrade, 5 days/wk for 55 wk. With training, hepatic and red gastrocnemius (RG) total glutathione increased, glutathione peroxidase (GPX) and glutathione reductase (GRD) increased in all the leg muscles studied, and hepatic glutathione S-transferase (GST) activity increased. J...