Acid Prevents L-2-Oxothiazolidine-4-Carboxylic Endotoxin-induced Cardiac Dysfunction BETTY Y. POON, CHRISTOPHER M. GODDARD, CYNTHIA D. LEAF, JAMES A. RUSSELL, and KEITH R. WALLEY Pulmonary Research Laboratory, St. Paul’s Hospital, University of British Columbia, Vancouver, British Columbia, Canada; and Transcend Therapeutics, Inc., Cambridge, Massachusetts We tested the hypothesis that treatment with the glutathione repleting agent, L-2-oxothiazolidine- 4-carboxylic acid (OTZ), could prevent endotoxin-induced ventricular dysfunction. Rabbits were treated with OTZ 2.4 g/kg (10% solution subcutaneously), or an equal volume and osmolality of sa- line, 24 h prior to, and again (intravenously) just prior to, infusion of 1 mg/kg E. coli endotoxin (or ve- hicle control). Ventricular contractility was measured in isolated hearts perfused by support rabbits. Contractility did not change in control groups (Saline/Control [n 7] or OTZ/Control [n 7]) over 6 h. However, Emax decreased in the Saline/Endotoxin group ( 16.1 4.5% from baseline, n 7, p 0.05) and this was prevented by pretreatment with OTZ in the OTZ/ Endotoxin group ( 6.3 4.1%, n 7, p 0.05 by analysis of variance). To better understand the mechanism of this effect we mea- sured myocardial glutathione concentration and found it to be greater in OTZ/Endotoxin animals (104 4 ng/g) than in the Saline/Endotoxin animals (80 3 ng/g, p 0.05). OTZ did not apprecia- bly alter the endotoxin-induced increase in serum concentration of tumor necrosis factor (TNF) or the endotoxin-induced increase in myocardial leukocyte content. We conclude that oxygen radicals contribute to the early decrease in left ventricular contractility after endotoxin infusion and this de- crease may be prevented by OTZ. Poon BY, Goddard CM, Leaf CD, Russell JA, Walley KR. L-2- oxothiazolidine-4-carboxylic acid prevents endotoxin-induced cardiac dysfunction. AM J RESPIR CRIT CARE MED 1998;158:1109–1113. When cardiovascular dysfunction complicates sepsis, the mor- ute to ventricular dysfunction during sepsis is not known. tality rate approximately doubles (1, 2), contributing to the However, release of reactive oxygen radicals by leukocytes is high and rising incidence of death due to serious infections. an important contributor to the pathogenesis of ischemia-rep- An important aspect of cardiovascular dysfunction of sepsis is erfusion injury in the heart (12–14). Thus, it is reasonable to decreased left ventricular function (3). A number of compo- postulate that oxygen radicals may be important in causing nents of the septic inflammatory cascade have been shown to ventricular dysfunction in sepsis. contribute to decreased ventricular function, including tumor Glutathione (GSH) is an important endogenous antioxidant necrosis factor (TNF) (4, 5), other proinflammatory cytokines that protects cells and tissues against oxygen radical damage (6), and leukocytes (7). TNF and other proinflammatory cy- (15–17). Continued release of oxygen radicals during sepsis tokines may mediate part of their effect via nitric oxide (NO), depletes the supply of glutathione, leaving tissues vulnerable either via NO’s effect of myocyte cyclic guanosine 3 ,5 -mono- to damage by oxygen radicals (9). Restoring glutathione con- phosphate (cyclic GMP) or via peroxynitrite formed by com- centrations is necessary to continue its protective role, but in- bination of NO with oxygen radicals (8). Leukocytes also me- creasing glutathione levels can be problematic. Direct admin- diate some of their damaging effects in other tissues via istration of glutathione is restricted because glutathione is easily oxygen radical formation (9). Whether oxygen radicals gener- oxidized and hydrolyzed by intestinal and hepatic -glutamyl- ated by myocytes, leukocytes (10, 11), or other cells, contrib- transferase (18). The rate of glutathione synthesis is usually limited by the amount of cysteine present (15). Cysteine, a glutathione precursor, is rapidly oxidized, has limited cell up- (Received in original form February 12, 1997 and in revised form May 20, 1998) take, and may be toxic when present extracellularly at high Supported by Transcend Therapeutics, Inc. and the Medical Research Council of Canada. concentrations (19, 20). However, glutathione repletion can be achieved effectively by administering L-2-oxothiazolidine- Christopher Goddard is a Fellow of the Heart and Stroke Foundation of British Columbia and Yukon. 4-carboxylic acid, OTZ (Procysteine; Transcend Therapeutics, Keith R. Walley is a Scholar of the Heart and Stroke Foundation of Canada. Inc., Cambridge, MA) (21). This compound is converted to cysteine by the intracellular enzyme, oxoprolinase (22). Correspondence and requests for reprints should be addressed to Keith R. Walley, M.D., U.B.C. Pulmonary Research Laboratory, St. Paul’s Hospital, 1081 Accordingly, we asked if OTZ could prevent decreased Burrard Street, Vancouver, BC, V6Z 1Y6 Canada. ventricular contractility observed after endotoxin infusion (5, Am J Respir Crit Care Med Vol 158. pp 1109–1113, 1998 23). We reasoned that OTZ would replenish depleted glu- Internet address: www.atsjournals.org tathione stores and enable the glutathione cycle to catabolize 1110 AMERICAN JOURNAL OF RESPIRATORY AND CRITICAL CARE MEDICINE VOL 158 1998 oxygen radicals. To address our hypothesis we used an iso- with normal saline via the Millar catheter lumen until a left ventricu- lated heart perfused by a support rabbit (7, 23). Endotoxin in- lar end-diastolic pressure of 4 mm Hg was achieved (volume approxi- fusion into the support rabbit provided a whole animal model mately 200 l). After the ventricular balloon and pacing electrodes of sepsis while the isolated heart allowed us to control coro- were in place, the isolated heart was then allowed to beat isovolumi- cally for 15 min. nary perfusion pressure, preload, afterload, heart rate, and eliminate mechanical interaction of the heart with surround- Measurement of Left Ventricular Function ing structures. Ventricular contractility was measured using the slope of the end-sys- tolic pressure-volume relationship, Emax (24). To calculate Emax, the METHODS intraventricular balloon was inflated using a syringe pump at a con- stant rate of 800 l/min to a maximal volume determined as the vol- This study was approved by the University of British Columbia Ani- ume at which cardiac dysrhythmia occurred (approximately 400 l). A mal Care Committee and adheres to the Canadian guidelines on ani- constant balloon inflation rate allowed time measurements to be con- mal experimentation. verted directly to intraventricular volume measurements. The maxi- mal balloon inflation volume never approached the balloon’s un- Pretreatment Protocol stressed volume of 3 ml. During inflation, left ventricular pressure was Fifty-six rabbits (New Zealand White) in the experiments were pre- sampled at 100 Hz and stored in digital format. The slope of the best- treated with either a total of 2.4 g/kg of a 10% OTZ solution (OTZ fit line to the ascending ramp of peak systolic pressures is Emax. Im- groups), or an equal volume and osmolality of saline (Saline groups), mediately after inflation to maximal volume, the balloon was deflated administered in three divided doses subcutaneously at 4-h intervals to the initial volume of approximately 200 l. beginning 24 h prior to the experiment. Measurements of Perfusing Blood Surgical Preparation of the Support Rabbit Arterial PO2, PCO2, and pH were measured using a blood gas analyzer Twenty-eight of the above rabbits (3.5 0.5 kg) were anesthetized us- (ABL30 Radiometer, Copenhagen, Denmark). We also measured ar- ing -chloralose (Sigma, St. Louis, MO) 55 mg/kg and urethane (32%; terial lactate concentration (YSI 2300 Stat Glucose-Lactate analyzer; Sigma) 4 ml/kg intravenously. A tracheotomy was performed and the YSI Incorporated, Yellow Springs, OH) and hemoglobin (IL482 Co- rabbits were ventilated with room air and supplemental oxygen to oximeter; Instrumentation Laboratory, Lexington, MA). maintain PCO2 between 30 to 40 mm Hg and PO2 above 100 mm Hg. Polyethylene catheters (interior diameter [i.d.] 1.67 mm, outer diame- Serum TNF Bioassay ter [o.d.] 2.42 mm; Intramedic, Becton Dickinson, Parsippany, NJ) were inserted into the right carotid artery and the left external jugular Serum TNF concentrations were measured using the WEHI bioassay vein. A third polyethylene catheter (i.d. 1.14 mm, o.d. 1.57 mm) was (25). Briefly, 5 105 WEHI 164 subclone 13 cells in 100 l were inserted into the left femoral artery to monitor arterial blood pressure. added to 100 l volumes of serial dilutions of serum samples, and Rabbits were anticoagulated with 1,000 IU/kg heparin (Organon; were incubated overnight. Then cell viability was measured with a col- Teknika, Toronto, ON, Canada) intravenously. A crystalloid solution orimetric assay using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazo- (Plasma-Lyte A, with 7 IU/ml heparin; Baxter Corp., Toronto, ON, lium bromide (MTT; Sigma). During the final 6 h of the incubations, Canada) was continuously infused via the left external jugular vein 20 l MTT (5 mg/ml in phosphate-buffered saline) was added to each catheter. Generally, the animals required 20 to 30 ml crystalloid dur- sample. Supernatant (150 l) was aspirated from each well and 100 l ing the surgical preparation of the isolated heart, and an additional 30 acidified isopropanol was added. Absorbance was measured at 550 to 40 ml/h throughout the experimental period. When pH fell below nm. TNF concentrations in experimental samples were calculated us- 7.35, 5-ml boluses of 6% sodium bicarbonate were given (approxi- ing a standard curve generated by serial dilutions of recombinant mu- mately 20 to 30 ml/experiment). A rectal temperature probe was in- rine TNF- . These bioassays consistently detected TNF concentra- serted and the core body temperature of the animal was maintained at tions above 1 pg/ml. 38.9 0.2 C using a heating blanket. Myocardial Leukocyte Content Langendorff Column and Extracorporeal Circuit Immediately after the conclusion of the experiment the blood perfu- The support rabbit was then connected to a circuit which perfused a sion circuit was interrupted and normal saline was simultaneously in- Langendorff column. Arterial blood from the right carotid catheter of fused into the isolated heart to flush out red blood cells from the myo- the support rabbit was pumped via a roller pump to an open perfusion cardial circulation (approximately 5 min). Glutaraldehyde 2.5% in column connected to a heated heart chamber, to produce a coronary phosphate buffer was then added to the saline perfusion circuit and perfusion pressure of 75 mm Hg at the level of the aortic valve of the the heart was perfusion fixed for 10 min. The isolated heart was then isolated heart. Blood overflowing from the perfusion column and removed from the apparatus and transferred to a container of the venous blood from the isolated heart was pumped back via a second same fixative. Left ventricular tissue sections (5 mm thickness) from roller pump through a 40- m blood filter (SQ40S Blood Transfusion hearts fixed in glutaraldehyde were dehydrated and embedded in par- filter; Pall Biomedical Products Corporation, East Hills, NY) to the affin. Serial sections (4 m thickness) were stained with hematoxylin support animal via the external jugular vein catheter. The total vol- and eosin. The number of random fields, at 400 original magnifica- ume of this circuit was approximately 35 ml. tion, necessary to count 100 leukocytes in each group was recorded. The average number of leukocytes per field was then determined as a Surgical Preparation of the Isolated Heart quantitative assessment of myocardial leukocyte content. The remaining 28 (out of the initial 56) rabbits (2.5 0.5 kg) were anesthetized with a mixture of ketamine 80 mg/kg and xylazine 5 mg/ Experimental Protocol kg subcutaneously. A midline sternotomy and pericardiotomy was On the day of the experiment an additional 2.4 g/kg OTZ 10% solu- performed. The hearts were rapidly excised and affixed via the aorta tion (OTZ groups) or equivalent volume of saline (Saline groups) was to the Langendorff column. The pulmonary artery was incised at the given intravenously at a rate of 2 ml/min over approximately 40 min base of the right ventricular outflow tract to allow venous drainage (21). One hour after the start of OTZ (or saline) infusion, baseline from the right ventricle. A 5-mm incision was made in the left atrium measurements were taken and 1 mg/kg endotoxin (lipopolysaccha- and a 7-French single-lumen pressure transducer (Millar Instruments ride; Sigma) (Endotoxin groups) or an equivalent volume of vehicle Inc., Houston, TX) surrounded by a saline-filled latex balloon (un- (Control groups) was given intravenously over 30 min. These two in- stressed volume 3 ml) was inserted into the left ventricle and secured terventions defined four experimental groups which were Saline/En- using an external ligature surrounding the left atrium. Pacing elec- dotoxin (n 7) and OTZ/Endotoxin (n 7) to test the hypothesis trodes were attached to both the left and right atria and the hearts that OTZ prevents endotoxin-induced ventricular dysfunction, and were paced at 150 beats/min. The ventricular balloon was inflated Saline/Control (n 7) and OTZ/Control (n 7) to control for time Poon, Goddard, Leaf, et al.: Oxygen Radicals and Cardiac Function 1111 effects and for any independent effects of OTZ. Variables were mea- statistical comparisons (Saline/Endotoxin versus OTZ/Endo- sured at baseline and 6 h after the start of endotoxin infusion. toxin p 0.009, Saline/Endotoxin versus Saline/Control p 0.034, or Saline/Endotoxin versus OTZ/Control p 0.005). Glutathione Assay Serum TNF concentrations increased to the same extent in In entirely separate experiments from those described previously, rab- the Saline/Endotoxin and OTZ/Endotoxin groups (Figure 2). bits were pretreated with OTZ (n 3) or with saline (n 3) and en- In the control groups that did not receive endotoxin, TNF was dotoxin was infused, as described. Six hours after the start of endo- initially slightly elevated, probably related to the surgical prep- toxin infusion, hearts were rapidly excised and snap-frozen in liquid nitrogen. Glutathione levels were measured in frozen heart tissue us- aration, and then decreased (Figure 2). Myocardial leukocyte ing the Bioxytech GSH-400 colorimetric assay (R&D Systems, Min- content of 1.5 0.2 leukocytes/field in the Saline/Control and neapolis, MN). Briefly, 500 mg of tissue were homogenized in 10 ml OTZ/Control groups increased to 2.4 0.2 leukocytes/field in ice-cold 5% metaphosphoric acid (Sigma). A volume of 100 l of su- the Saline/Endotoxin and OTZ/Endotoxin groups (p 0.005) pernatant was then mixed with 800 l buffer (200 mM potassium (Figure 3). However, OTZ administration had no significant phosphate, pH 7.8 at 25 C, containing 0.2 mM diethylenetriamine effect on myocardial leukocyte concentration. pentaacetic acid and 0.025% lubrol), 50 l each of a solution of 1.2 In separate experiments we found that myocardial glu- 10 2 M chromogenic reagent in 0.2N hydrochloric acid and 30% so- tathione concentrations were greater in rabbits treated with dium hydroxide (Bioxytech GSH-400 kit; R&D Systems). After a 10- OTZ (104 4 ng/g) than in those treated with saline (80 min incubation at 25 C, absorbance was measured at 400 nm. Glu- tathione levels were calculated using a standard curve generated by 3 ng/g) (p 0.05) 6 h after the start of the endotoxin infusion. serial dilutions of glutathione in solution (Sigma). There were no differences between groups in blood gas measurements, lactate, or hemoglobin of support rabbit blood Data Analysis that perfused the isolated hearts that could account for the We tested the principal null hypothesis that there was no difference in measured difference in contractility between the Saline/En- contractility (Emax) between the four experimental groups at 6 h af- dotoxin and OTZ/Endotoxin groups (Table 1). ter the start of endotoxin infusion with a two-way repeated measures analysis of variance (ANOVA) using p 0.05 as significant. Specifi- DISCUSSION cally, when we analyzed the data we included a factor for absence/ presence of OTZ, one for absence/presence of endotoxin, and an in- These results show that OTZ, a cysteine prodrug and glu- teraction term between the two. When a significant difference was tathione repleting agent (16, 21), prevents the early decrease identified we used a sequentially rejective Bonferroni test procedure in ventricular contractility in isolated-perfused hearts follow- to identify specific differences. Similar analysis was used to test for ing endotoxin infusion into support rabbits. Similar to previ- differences in other measured variables. Data are reported as mean ous reports (16, 17, 21, 22), OTZ administration also increased standard error. myocardial glutathione concentrations after endotoxin infu- sion. These results support the hypothesis that oxygen radicals RESULTS contribute to the early decrease in ventricular contractility in Emax decreased by 16.1 4.4% in the Saline/Endotoxin sepsis. group (Figure 1) but did not decrease in the OTZ/Endotoxin OTZ administration did not alter serum TNF expression or group ( 6.3 4.1%) by 6 h after the start of endotoxin infu- the myocardial leukocyte retention that occurred after endo- sion. Emax did not change significantly from baseline to 6 h in toxin infusion. One possible explanation is that TNF and oxy- either of the Saline/Control or OTZ/Control groups (Figure 1). gen radical effects are unrelated and caused by separate mecha- The statistical interaction between OTZ and endotoxin was nisms. Alternatively, these data suggest that oxygen free significant (p 0.029) and the Saline/Endotoxin group dif- radicals, modulated by OTZ, have myocardial depressant ef- fered from all three other groups after correction for multiple fects downstream in the septic inflammatory response from Figure 2. Average serum TNF concentrations are shown with stan- Figure 1. Contractility, as measured by average Emax, is shown at dard error bars. Endotoxin infusion causes a marked increase in se- 6 h after the start of endotoxin infusion, with standard error bars. rum TNF concentration (endotoxin effect, p 0.018) but there is Emax decreases significantly in the Control/Endotoxin group com- no statistically significant effect of OTZ (p 0.788) and no statisti- pared with all other groups (*p 0.05, ANOVA). For the key pro- cally significant interaction between OTZ and endotoxin (p spectively planned comparison of the Control/Endotoxin to OTZ/ 0.402). Standard errors in the Saline/Control group are so small Endotoxin groups, p 0.007 by ANOVA. the error bars lie within the symbols. 1112 AMERICAN JOURNAL OF RESPIRATORY AND CRITICAL CARE MEDICINE VOL 158 1998 that oxygen radicals play in septic myocardial dysfunction has not been determined. In 1981, Williamson and Meister described OTZ as a cys- teine delivery system and glutathione enhancer (16). Oxopro- linase, an enzyme present in most mammalian cells, metabo- lizes OTZ into cysteine and CO2 at the expense of ATP. OTZ treatment maintained cellular glutathione levels when gluta- thione-depleting agents were given to healthy animals (32, 33) and OTZ repleted tissue glutathione levels in acutely septic rats (34). In accord with these studies we found that OTZ in- creased myocardial glutathione concentration, measured 6 h after endotoxin infusion. Thus, OTZ administration is an in- tervention that allowed us to test for a possible myocardial de- pressant effect of oxygen radicals. Oxygen free radicals come from several sources and could have several effects in the heart. Activated neutrophils are im- portant sources of oxygen radicals and activated neutrophils accumulate in the heart after endotoxin infusion in animal Figure 3. Average leukocyte count in the myocardium (sampled models (7, 10, 11, 23). Filtering leukocytes from coronary blood immediately after the 6-h time point measurements) per 400 prevents the early decrease in ventricular contractility after field is shown for all four groups with standard error bars. ANOVA endotoxin infusion in rabbits (7). Because OTZ also pre- shows that there is a significant endotoxin effect (*p 0.05) but vented the early decrease in contractility in a similar experi- that there is no OTZ effect (p NS). mental model, it is reasonable to postulate that neutrophils mediate much of their myocardial depressant effects via oxy- gen radicals. However, the decrease in contractility is not nec- proinflammatory cytokines (6) and downstream from leuko- essarily due to leukocyte release of oxygen radicals. It is also cytes, which accumulate in the heart (7, 10, 11, 23) and con- possible that leukocytes decrease ventricular contractility by tribute to the early decrease in ventricular contractility in other means, such as cytokine release, and it is conceivable models of sepsis (7). that OTZ could have protected cells from other oxidant stress Myocardial dysfunction has been reported in human sepsis generated within the myocytes. Alternatively, oxygen radicals (3) and in animal models of sepsis (4, 5, 7, 10, 23). A number may decrease contractility via intracellular oxidant signaling of mechanisms have been identified (26–30). Circulating myo- (35) without necessarily damaging tissue (36). OTZ could cardial depressant factors appear to contribute (26). Proin- modify intracellular oxidant signaling (35) and prevent this ef- flammatory cytokines (6), notably TNF (4, 5, 6, 27), may act as fect without altering tissue morphometry. myocardial depressant factors. These cytokines may mediate A number of issues related to the experimental model part of their effect via NO generation from nearby endothe- should be addressed. The decrease in contractility and in- lium, from cardiac myocytes (8), and from other cellular sources. crease in serum TNF concentration observed after endotoxin NO may mediate its myocardial depressant effects in several administration in this model resembles that observed after ways, including by increasing cyclic GMP activity (28) and also acute endotoxin or proinflammatory cytokine administration by forming peroxynitrite after combining with oxygen radicals in other animal models (4, 5, 7, 10, 23) and in acute studies in (29). The importance of NO is uncertain as other studies do humans (37). However, whether this endotoxin infusion model not show NO-mediated myocardial depression in animal mod- in rabbits models the cardiovascular changes over days de- els of sepsis (30). In addition, other inflammatory mediators scribed in human septic shock (3) is not known. Therefore, (e.g., platelet activating factor  ) and leukocytes (7) appear these results should be interpreted in this light and limited to to contribute to myocardial dysfunction in sepsis. The role the early decrease in contractility after an initiating septic stimulus. Differences in contractility between the Saline/En- dotoxin group and the OTZ/Endotoxin group were indepen- dent of any changes in myocardial perfusion pressure, pre- load, afterload, heart rate, and ventricular interaction (4, 24) TABLE 1 because these factors were all kept constant in the isolated- MEASUREMENTS OF PERFUSING BLOOD* supported heart where Emax was measured. Similarly, PO2, Saline/ Saline/ OTZ/ OTZ/ PCO2, pH, lactate, and hemoglobin of support rabbit blood Time Control Endotoxin Control Endotoxin that perfused the isolated hearts did not account for the mea- sured difference in contractility between the Saline/Endotoxin PO2, mm Hg 0 519 16 504 14 450 30 525 13 and OTZ/Endotoxin groups. Although lactate rose with time 6 527 14 451 49 534 19 513 16 in support rabbit blood, there was no significant difference be- PCO2, mm Hg 0 37.6 3.9 39.7 3.6 37.3 2.5 34.6 2.2 tween groups. Thus, the effect of OTZ treatment on endo- 6 43.1 2.6 41.6 2.8 34.5 1.1 40.2 1.6 toxin-induced ventricular dysfunction is not accounted for by pH 0 7.26 0.04 7.25 0.07 7.33 0.03 7.33 0.02 these differences in perfusing blood. 6 7.33 0.03 7.31 0.04 7.37 0.03 7.29 0.01 In summary, OTZ treatment increases myocardial glu- Lactate, mmol/L 0 2.1 0.4 1.9 0.3 1.9 0.4 2.3 0.7 tathione concentration and prevents the early decrease in con- 6 4.7 1.5 12.9 0.9† 8.1 1.6† 10.5 1.1† tractility after endotoxin infusion, implying that oxygen radi- Hemoglobin, g/dl 0 9.4 0.8 9.7 0.6 9.9 0.5 9.1 0.2 cals are in part responsible for impaired ventricular function. 6 7.4 0.4† 7.5 0.5† 7.9 0.3† 7.1 0.4† Oxygen radical–mediated ventricular dysfunction may account * Values are expressed as mean standard error. for some of the previously observed leukocyte-mediated myo- † Different from Time 0 baseline, p 0.05. cardial dysfunction after endotoxin infusion (7). Poon, Goddard, Leaf, et al.: Oxygen Radicals and Cardiac Function 1113 References 20. Karisen, R. L., I. Grofova, D. Malthe-Sorenssen, and F. Fonnum. 1981. Morphological changes in the brain induced by L-cysteine injection in 1. Balk, R. A., and R. C. Bone. 1989. The septic syndrome. Crit. Care Clin- newborn animals. Brain Res. 208:167–180. ics 5:1–8. 21. Leaf, C. D., and G. W. Pace. 1994. Development of a novel glutathione re- 2. Bone, R. C., C. J. Fischer, Jr., T. P. Clemmer, G. J. Slotman, C. A. Metz, pleting agent, L-2-oxothiazolidine-4-carboxylic acid (Procysteine TM). R. A. Balk, and Methylprednisolone Severe Sepsis Study Group. Exp. Opin. Invest. Drugs 3:1293–1302. 1987. A controlled clinical trial of high-dose methylprednisolone in 22. Meister, A., M. Anderson, and O. Hwang. 1986. Intracellular cysteine the treatment of severe sepsis and septic shock. N. Engl. J. Med. 317: and glutathione delivery systems. J. Am. Coll. Nutr. 5:137–151. 653–658. 23. Goddard, C. M., M. F. Allard, J. C. Hogg, and K. R. Walley. 1996. Myo- 3. Parker, M. M., J. H. Shelhamer, S. L. Bacharach, M. V. Green, C. Natan- cardial morphometric changes related to decreased contractility after son, T. M. Frederick, B. A. Damske, and J. E. Parillo. 1984. Profound endotoxin. Am. J. Physiol. 270:H1446–H1452. but reversible myocardial depression in patients with septic shock. 24. Kass, D. A., W. L. Maughan, Z. M. Guo, A. Kono, K. Sunagawa, and K. Ann. Intern. Med. 100:483–490. Sagawa. 1987. Comparative influence of load versus inotropic state on 4. Walley, K. R., P. C. Hebert, Y. Wakai, P. G. Wilcox, J. D. Road, and D. J. indexes of ventricular contractility: experimental and theoretical anal- Cooper. 1994. Decrease in left ventricular contractility after tumor ne- ysis based on pressure–volume relationships. Circulation 76:1422– crosis factor- infusion in dogs. J. Appl. Physiol. 76:1060–1067. 1436. 5. Herbertson, M. J., H. A. Werner, C. M. Goddard, J. A. Russell, A. 25. Eskandari, M. K., D. T. Nguyen, S. L. Kunkel, and D. G. Remick. 1990. Wheeler, R. Coxon, and K. R. Walley. 1995. Anti-tumor necrosis fac- WEHI 164 subclone 13 assay for TNF: sensitivity, specificity, and reli- tor- prevents decreased ventricular contractility in endotoxemic pigs. ability. Immunol. Invest. 19:69–79. Am. J. Respir. Crit. Care Med. 152:480–488. 26. Parrillo, J. E., C. Burch, J. H. Shelhamer, M. M. Parker, C. Natanson, 6. Finkel, M. S., C. V. Oddis, T. D. Jacob, S. C. Watkins, B. G. Hattler, and and W. Schuette. 1985. A circulating myocardial depressant substance R. L. Simmons. 1992. Negative inotropic effects of cytokines on the in humans with septic shock. J. Clin. Invest. 76:1539–1553. heart mediated by nitric oxide. Science 257:387–389. 27. Natanson, C. 1990. Studies using a canine model to investigate the car- 7. Granton, J. T., C. M. Goddard, M. F. Allard, S. vanEeden, and K. R. diovascular abnormality of and potential therapies for septic shock. Walley. 1997. Leukocytes and decreased left-ventricular contractility Clin. Res.. 38:206–214. during endotoxemia in rabbits. Am. J. Respir. Crit. Care Med. 155: 28. Hung, J., and W. Y. W. Lew. 1993. Cellular mechanisms of endotoxin- 1977–1983. induced myocardial depression in rabbits. Circ. Res. 73:125–134. 8. Brady, A. J. B., P. A. Poole-Wilson, S. E. Harding, and J. B. Warren. 29. Schulz, R., D. L. Pauas, R. Catena, S. Moncada, P. M. Olley, and G. D. 1992. Nitric oxide production within cardiac myocytes reduces their Lopaschuk. 1995. The role of nitric oxide in cardiac depression in- contractility in endotoxemia. Am. J. Physiol. 263:H1963–H1966. duced by interleukin-1 and tumor necrosis factor- . Br. J. Pharma- 9. Brigham, K. L., and B. Meyrick. 1986. Endotoxin and lung injury. Am. col. 114:27–34. Rev. Respir. Dis. 133:913–917. 30. Decking, U. K. M., C. W. Flesche, A. Godecke, and J. Schrader. 1995. 10. Goddard, C. M., M. F. Allard, J. C. Hogg, M. J. Herbertson, and K. R. Endotoxin-induced contractile dysfunction in guinea pig hearts is not Walley. 1995. Prolonged leukocyte transit time in coronary microcir- mediated by nitric oxide. Am. J. Physiol. 268:H2460–H2465. culation of endotoxemic pigs. Am. J. Physiol. 269:H1389–H1397. 31. Herbertson M. J., H. A. Werner, and K. R. Walley. 1997. Platelet-acti- 11. Barroso-Aranda, J., G. W. Schmid-Schoenbein, B. W. Zweifach, and vating factor antagonism improves ventricular contractility in endo- J. C. Mathison. 1992. Polymorphonuclear neutrophil contribution to toxemia. Crit. Care Med. 25:221–226. induced tolerance to bacterial lipopolysaccharide. Circ. Res. 69:1196– 32. Goldberg, D. I., D. Madsen, W. B. Rowe, I. Webb, S. Young, and R. C. 1206. Johnston. 1992. Absorption, distribution, metabolism and excretion of 12. Entman, M. L., K. Youker, T. Shoji, G. Kukielka, S. B. Shapell, A. A. orally administered [14C] ProcysteineTM in rats. International Confer- Taylor, and C. W. Smith. 1992. Neutrophil induced oxidative injury of ence on AIDS. Berlin, Germany. cardiac myocytes. J. Clin. Invest. 90:1335–1345. 33. Williamson, J.M., B. Boettcher, and A. Meister. 1982. Intracellular cys- 13. McCord, J. M. 1985. Oxygen-derived free radicals in postischemic tissue teine delivery system that protects against toxicity by promoting glu- injury. N. Engl. J. Med. 312:159–163. tathione synthesis. Proc. Nat. Acad. Sci. U.S.A. 79:6246–6249. 14. Thompson, J. A., and M. L. Hell. 1986. The oxygen free radical system: a 34. Kaeffer, N., J. Pett, B. Dieu, B. Heckeetsweiler, J. F. Lemand, F. Rose, fundamental mechanism in the production of myocardial necrosis. D. Goldberg, and E. Lerebours. 1993. L-2-oxothiazolidine-4-carboxy- Prog. Cardiovasc. Dis. 28:449–462. lic acid as a cysteine precursor in acute experimental sepsis in rats: ef- 15. Meister, A., and M. E. Anderson. Glutathione. 1983. Annu. Rev. Bio- fects on tissue glutathione and cysteine levels. First European Work- chem. 52:711–760. shop on Glutathione, France. 16. Williamson, J. M., and A. Meister. 1981. Stimulation of hepatic glu- 35. Downey, G. P., C. K. Chan, and L. Fialkow. 1994. NADPH oxidase– tathione formation by administration of L-2-oxothiazolidine-4-carbox- derived reactive oxygen intermediates regulate tyrosine phosphoryla- ylate, a 5-oxo-L-prolinase substrate. Proc. Nat. Acad. Sci. U.S.A. 78: tion in human neutrophils. Chest 105:85S. 936–939. 36. Duranteau, J., N. S. Chandel, A. Kulisz, Z. Shao, and P. T. Schumacker. 17. Meister, A. 1983. Selective modification of glutathione metabolism. Sci- 1998. Intracellular signaling by reactive oxygen species during hy- ence 220:472–477. poxia: role of mitochondrial cytochrome oxidase (abstract). Am. J. 18. Witschi, A., S. Reddy, B. Stofer, and B. H. Lauterburg. 1992. The sys- Respir. Crit. Care Med. 157:A691. temic availability of oral glutathione. Eur. J. Clin. Pharmacol. 43:667– 37. Ognibene, F. P., S. A. Rosenberg, M. Lotze, J. Skibber, M. M. Parker, 669. J. H. Shelhamer, and J. E. Parrillo. 1988. Interleukin-2 administration 19. Olney, J. W., O. L. Ho, and V. Rhee. 1971. Cytotoxic effects of acidic causes reversible hemodynamic changes and left ventricular dysfunc- and sulphur containing amino acids on the infant mouse central ner- tion similar to those seen in septic shock. Chest 94:750–754. vous system. Exp. Brain Res. 14:61–76.
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