Biomedical subjects

I H Chaudry

Publications and source records attributed to I H Chaudry.

At least 19 recordsLinked to original sources

PubMed2006

Castration prevents suppression of MHC class II (Ia) expression on macrophages after trauma-hemorrhage.

Several studies indicate that cell-mediated immune responses, i.e., macrophage (MPhi) cytokine release capacities, myosin heavy chain (MHC) class II (Ia) expression, etc., are suppressed after trauma-hemorrhage in male mice. Testosterone has been shown to be responsible for the depression of MPhi cytokine responses in males after trauma-hemorrhage. Antigen presentation via MHC class II plays a key role in initiating and maintaining cell-mediated and humoral immune responses. It remains unknown, however, whether testosterone has any effect on MHC class II after trauma-hemorrhage. To study this, male C3H/HeN mice were castrated or sham castrated 2 wk before trauma (midline laparotomy) and hemorrhage (Hem; blood pressure 35 +/- 5 mmHg for 90 min and resuscitation) or sham operation. Four hours thereafter, MHC class II (Ia) expression was measured using flow cytometry. The results indicate that MHC class II (Ia) expression on peritoneal and splenic MPhi was significantly suppressed in male mice after trauma-hemorrhage. Prior castration, however, prevented the depression in MHC class II (Ia) expression on peritoneal and splenic MPhi after trauma-hemorrhage. Castration did not affect MHC class II (Ia) expression in MPhi from sham-castrated mice. Thus testosterone depresses MHC class II (Ia) expression on peritoneal and splenic MPhi after trauma-hemorrhage in males. Because MHC class II is necessary for an adequate immune response, our results suggest that depletion of male sex steroids or blockade of androgen receptors using agents such as flutamide might prevent immunosuppression via maintaining MHC class II (Ia) expression after trauma and severe blood loss.

Androgen Antagonists↗

PubMed2005

L-arginine improves wound healing after trauma-hemorrhage by increasing collagen synthesis.

BACKGROUND: Several studies indicate impaired wound healing after trauma and shock. Wound immune cell dysfunction seems to be responsible for altered wound healing after trauma-hemorrhage (T-H). In this respect, administration of the amino acid L-arginine normalized wound immune cell function under those conditions. It remains unknown, however, whether L-arginine improves impaired wound healing after T-H. METHODS: To study this, male C3H/HeN mice were subjected to a midline laparotomy (i.e., soft tissue trauma induced), and polyvinyl sponges were implanted subcutaneously at the wound site before hemorrhage (35 +/- 5 mm Hg for 90 minutes) or were subjected to sham operation. During resuscitation, mice received 300 mg/kg body weight L-arginine or saline (vehicle). Seven days thereafter, hydroxyproline (OHP), a metabolite of collagen synthesis, was measured in the wound fluid using high-performance liquid chromatography. Collagen types I and III were determined in the wound by Western blot analysis. In addition, wound breaking strength was measured 10 days after T-H or sham operation. RESULTS: The results indicate that OHP was significantly decreased in T-H mice. L-arginine, however, restored depressed OHP in the wound fluid in the T-H animals. Similarly, L-arginine treatment prevented a significant depression of collagen I synthesis after T-H. Collagen III was not significantly affected by T-H or L-arginine. Most important, L-arginine increased maximal wound breaking strength after severe blood loss. Therefore, L-arginine improves wound healing after T-H by increasing collagen synthesis. CONCLUSION: Because L-arginine improves wound healing, the results suggest that L-arginine might represent a novel and useful adjunct to fluid resuscitation for decreasing wound complications after trauma and severe blood loss.

Analysis of Variance↗

PubMed2004

Differences in the expression of LPS-receptors are not responsible for the sex-specific immune response after trauma and hemorrhagic shock.

Several studies demonstrated a sex-specific cytokine secretion by macrophages following trauma-hemorrhage (T-H) and incubation with lipopolysaccharide A (LPS). Although LPS is known to act via the receptors CD14 and TLR4 on macrophages, it remains unknown whether differences in LPS receptor expression in males and females may be responsible for the gender-specific LPS induced cytokine response following (T-H). To study this, male and proestrus female mice (C3H/HeN) were subjected to trauma (laparotomy) followed by hemorrhage or sham operation. At 2 h thereafter, SMphi and PMphi were harvested and cultured for 2 h. The expression of CD14 and TLR4 was measured by flow cytometry on unstimulated SMphi and PMphi as well as after LPS stimulation. The results indicate that the expression of CD14 and TLR4 on SMphi and PMphi from female and male mice was similar in sham-operated animals and after (T-H). Incubation of macrophages with LPS did not alter CD14 and TLR4 expression in the study groups. Thus, the sex specific LPS induced cytokine secretion after (T-H) is not caused by differences in LPS receptor expression on Mphi of male and female mice.

Animals↗

PubMed2002

Soluble Fas gene therapy protects against Fas-mediated apoptosis of hepatocytes but not the lethal effects of Fas-induced TNF-alpha production by Kupffer cells.

The elevation of soluble Fas (sFas) in the sera of patients with liver disease suggests a role for sFas in the disease process; whether it is protective or not is controversial. To determine the effects of sFas on Fas-induced liver apoptosis, we manipulated mice to produce sFas by transfecting them in vivo with different amounts of an adenovirus that produces mouse sFas driven by the CMV promoter (AdsFas). Fas-mediated apoptosis was induced by administration of anti-mouse Fas (Jo2; 10 microg/mouse) one week later. The administration of AdsFas (10(3), 10(7), or 10(9) pfu/mouse), which was associated with only minimal side-effects, resulted in a significant reduction in the liver transaminase levels and mortality of the mice on challenge with Jo2, as compared to control mice treated with AdLacZ. However, the protective effect of AdsFas was not complete. The possibility that Jo2-induction of TNF-alpha in the Kupffer cells of the liver contributes to the pathology was therefore tested. Although administration of soluble TNF receptor (sTNFRI) alone did not protect the mice from the lethal effects of Jo2, administration of sTNFRI (200 microg/mouse) after infection with AdsFas (10(9) pfu/mouse) resulted in 100% survival of the mice on challenge with Jo2. To confirm that the production of TNF-alpha by Kupffer cells produce the lethal effects of Jo2 that remained after treatment with AdsFas, these cells were selectively ablated by treatment of the mice with gadolinium chloride prior to challenge with Jo2. This treatment greatly reduced early mortality and hepatocellular damage as well as TNF-alpha production 6 h after injection of Jo2. These results indicate that: (1) AdsFas prevents Jo2-induced apoptosis of hepatocytes; (2) In addition to mediating Fas-mediated apoptosis of hepatocytes, Jo2 can separately induce TNF-alpha production by Kupffer cells resulting in early mortality, and (3) Optimal protection from Jo2-induced mortality can be achieved by protection of liver cells by pretreatment with both AdsFas and sTNFRI.

Animals↗

PubMed2001

Testosterone and estrogen differently effect Th1 and Th2 cytokine release following trauma-haemorrhage.

The object of the study was to determine whether male and female sex steroids produce divergent effects on Th1 and Th2 cytokine release following trauma-haemorrhage. Recent studies indicate that androgens are responsible for the depressed splenocyte Th1 cytokine release in males following trauma-haemorrhage. In contrast, female mice maintain their Th1 cytokine release capacity following trauma-haemorrhage. Nonetheless, the effect of male and female sex steroids on Th1 and Th2 cytokine release following trauma-haemorrhage remains unknown. Male C3H/HeN mice were castrated and treated with pellets containing either vehicle, 5alpha-dihydrotestosterone (DHT), 17beta-estradiol (estradiol), or a combination of both steroid hormones, for 14 days prior to soft-tissue trauma (i.e. laparotomy) and haemorrhagic shock (35+/-5 mmHg for 90 min followed by adequate fluid resuscitation) or sham operation. Untreated male and female mice, as well as DHT treated female mice, served as control groups. Twenty-four hours later the animals were sacrificed, plasma obtained and splenocytes harvested. Plasma DHT and estradiol levels in treated animals were comparable with intact male and female mice, respectively. A significant depression of splenocyte Th1 cytokines, i.e. IL-2, IFN-gamma, was observed in DHT treated castrated animals, DHT treated females, and untreated males following trauma-haemorrhage, as opposed to maintained Th1 cytokine release in estradiol treated and estradiol/DHT treated castrated animals and females. The release of the anti-inflammatory cytokine IL-10 was markedly increased in DHT treated mice and males subjected to trauma-haemorrhage compared to shams, but decreased in estrogen treated mice and females under such conditions. These results suggest that male and female sex steroids differentially affect the release of Th1 and Th2 cytokines following trauma-haemorrhage and should be further studied for their potential to modulate splenocyte function in trauma victims.

Animals↗

PubMed2001

The role of lipopolysaccharide in stimulating adrenomedullin production during polymicrobial sepsis.

Previous studies have shown that adrenomedullin (AM), a potent vasodilatory peptide, is upregulated during sepsis. However, it remains unknown whether the increased AM observed under such conditions is solely due to the elevated levels of circulating lipopolysaccharide (LPS). To determine this, an Alzet micro-osmotic pump, containing a low dose of Escherichia coli LPS or vehicle (sterile normal saline), was implanted in the peritoneal cavity of the normal male adult rat. At 10 h after the pump implantation, samples of blood and small intestine were harvested for the determination of AM by radioimmunoassay. In additional groups, rats were subjected to polymicrobial sepsis by cecal ligation and puncture (CLP). LPS binding agent polymyxin B was administrated intramuscularly at 1 h prior to as well as 5 h after the onset of sepsis. At 10 h after CLP or sham-operation, blood and intestinal samples were harvested and levels of AM were then determined. Plasma levels of LPS were also measured by Limulus amebocyte lysate assay. The results indicate that administration of a low dose of LPS via the peritoneal cavity in normal animals (which did not significantly alter cardiac output, blood pressure or heart rate) markedly increased plasma and intestinal levels of AM. In addition, plasma and tissue levels of AM increased significantly at 10 h after CLP. Administration of polymyxin B, however, attenuated the increase in AM levels under such conditions. Similarly, the increased plasma levels of LPS was significantly reduced by polymyxin B during sepsis. These results, taken together, suggest that the upregulated AM observed during polymicrobial sepsis is at least in part due to the increase in circulating levels of endotoxin.

Adrenomedullin↗

PubMed2001

The role of Kupffer cell alpha(2)-adrenoceptors in norepinephrine-induced TNF-alpha production.

Although previous studies have demonstrated that plasma levels of the proinflammatory cytokine tumor necrosis factor-alpha (TNF-alpha) increase during early sepsis, the precise mechanism responsible for its upregulation remains to be elucidated. Since recent studies have shown that the gut is an important source of norepinephrine (NE) release during early sepsis and enterectomy prior to the onset of sepsis attenuates TNF-alpha production, we hypothesized that gut-derived NE plays a major role in upregulating TNF-alpha via the activation of alpha(2)-adrenoceptors on Kupffer cells. To confirm that NE increases TNF-alpha synthesis and release, Kupffer cells were isolated from normal rats and incubated with NE (20 or 50 nM) or another alpha(2)-adrenergic agonist clonidine (50 nM) without addition of Escherichia coli endotoxin. Supernatant levels of TNF-alpha were then measured. In additional animals, intraportal infusion of NE (20 microM) with or without the specific alpha(2)-adrenergic antagonist yohimbine (1 mM) at a rate of 13 microl/min was carried out for 2 h. Plasma and Kupffer cell levels of TNF-alpha were assayed thereafter. Moreover, the effects of NE and yohimbine on TNF-alpha production was further examined using an isolated perfused liver preparation. The results indicate that both NE and clonidine increased TNF-alpha release by approximately 4-7-fold in the isolated cultured Kupffer cells. Similarly, intraportal infusion of NE in vivo or in isolated livers increased TNF-alpha synthesis and release which was inhibited by co-infusion of yohimbine. Furthermore, the increased cellular levels of TNF-alpha in Kupffer cells after in vivo administration of NE was also blocked by yohimbine. These results, taken together, suggest that gut-derived NE upregulates TNF-alpha production in Kupffer cells through an alpha(2)-adrenergic pathway, which appears to be responsible at least in part for the increased levels of circulating TNF-alpha observed during early sepsis as well as other pathophysiologic conditions such as trauma, hemorrhagic shock, or gut ischemia/reperfusion.

Adrenergic alpha-Agonists↗

PubMed2001

Dehydroepiandrosterone restores hepatocellular function and prevents liver damage in estrogen-deficient females following trauma and hemorrhage.

INTRODUCTION: Recent studies have shown that administration of the sex steroid dehydroepiandrosterone (DHEA) in males following trauma-hemorrhagic shock has salutary effects on the depressed cardiovascular and immunological functions under those conditions. Since the effects of sex steroids are gender specific, we examined whether administration of DHEA has any beneficial effects on hepatocellular function in female rats with low estrogen levels following trauma-hemorrhage. METHODS: Ovariectomy was performed in female Sprague-Dawley rats 14 days prior to the experiments. The animals then underwent a 5-cm midline laparotomy and were subjected to hemorrhagic shock (40 mm Hg for 90 min). This was followed by fluid resuscitation (Ringer's lactate over 60 min) and administration of DHEA (30 mg/kg BW) or vehicle subcutaneously at the end of resuscitation. At 24 h after resuscitation hepatocellular function, i.e., clearance of indocyanine green (ICG), and hepatocyte damage (serum alanine aminotransferase) were measured. Plasma levels of DHEA and 17beta-estradiol were also assayed. RESULTS: Vehicle-treated rats had significantly reduced hepatocellular function, increased ALT activity, and decreased levels of 17beta-estradiol following trauma-hemorrhage compared to sham-operated animals (P < 0.05, ANOVA and Student-Newman-Keuls test). In animals receiving DHEA following trauma-hemorrhage, hepatocellular function and ALT activity were similar to those of shams. However, administration of DHEA did not influence the plasma levels of 17beta-estradiol. CONCLUSIONS: Administration of DHEA following trauma-hemorrhage restored hepatocellular function and reduced hepatic damage that was observed in ovariectomized female rats under such conditions. This salutary effect of DHEA did not appear to be due to elevated levels of plasma 17beta-estradiol. We therefore propose that DHEA should be considered a novel, safe, and useful adjunct in the treatment of trauma-induced hepatocellular dysfunction in ovariectomized and postmenopausal females.

Adjuvants, Immunologic↗

PubMed2001

Gender differences in the inflammatory response and survival following haemorrhage and subsequent sepsis.

Studies have shown gender dimorphism in cell-mediated immune responses following haemorrhage, with depressed responses in young males and maintained or enhanced responses in proestrus females. However, it remains unknown whether or not the sexually dimorphic immune response to haemorrhage provides any protection against a subsequent in vivo polymicrobial septic challenge. To study this, male and proestrus female C3H/HeN mice were subjected to haemorrhage (35+/-5 mmHg for 90 min followed by fluid resuscitation) or sham operation. Twenty-four hours thereafter, all mice were subjected to polymicrobial sepsis by cecal ligation and puncture (CLP) and survival was assessed over a 10 day period. Haemorrhage prior to CLP significantly increased mortality in males as compared to shams. In contrast, mortality in females following CLP was comparable between the sham and haemorrhage groups. Plasma levels of interleukin (IL-)6, tumour necrosis factor (TNF)-alpha and prostaglandin E(2)(PGE(2)) at 5 h after CLP were significantly increased in males subjected to prior haemorrhage. In contrast, plasma levels of IL-6 and TNF-alpha in females did not increase under such conditions. PGE(2)levels were comparable in males and females following CLP, however prior haemorrhage significantly reduced PGE(2)levels in females, whereas no change was observed in males. Liver and splenic expression of cyclooxygenase-2 protein paralleled the changes in plasma PGE(2). Female sex hormones, therefore, appear to play an important role not only in maintaining immune function following haemorrhage, but also provide a survival advantage against subsequent septic challenge.

Animals↗

PubMed2001

IL-10 mediation of activation-induced TH1 cell apoptosis and lymphoid dysfunction in polymicrobial sepsis.

Recent studies suggest that increased activation-induced lymphocyte apoptosis (AICD) is detected in mouse splenocytes during polymicrobial sepsis which may contribute to lymphocyte immune dysfunction [i.e., decreased interleukin (IL-)2 and interferon-gamma (IFN-gamma) production] leading to the associated morbidity seen in those animals. Thus, we wanted to examine the hypothesis that immune suppressive agents, such as IL-4, IL-10 or prostaglandin E2(PGE2), known to be elevated in septic animals, also contribute to this increase in AICD. Here we demonstrate that the inclusion of monoclonal antibody (mAb) to IL-10, but not anti-IL-4 or ibuprofen (IBU), blunted this sepsis induced increase in splenocyte AICD. Additionally, septic mice deficient in the IL-10 gene product (-/-) showed neither an increase in AICD nor a loss of IL-2/IFN-gamma release capacity. Interestingly, mAb to IL-10 did not altered the extent of AICD in a Th2-cell line, but exogenous IL-10 did potentiate Th1-like cell line AICD. This was consistent with the finding that the increased AICD seen in septic mouse splenocytes was restricted largely to the CD4+ cells producing IL-2 (Th1-cells) and that mAb to IL-10 treatment suppressed this change. Furthermore, IL-10 appears to mediate its AICD effect by upregulation of the Fas receptor and Fas receptor signaling protein components, but not by altered expression of Bcl/Bax/Bad family members, in septic mouse splenocytes. To the extent that these processes contribute in a pathological fashion to the animal's capacity to survive sepsis we have previously observed that in vivo post-treatment of mice with mAb IL-10 markedly attenuated septic mortality. Collectively, these data indicate that in the septic mouse the Th2 cytokine IL-10 not only serves to actively induce Th1 lymphocyte immune dysfunction but also plays a role in their apoptotic depletion. These processes in turn appear to contribute to the animal's inability to ward off lethal septic challenge.

Animals↗

PubMed2001

Attenuation of vascular endothelial dysfunction by testosterone receptor blockade after trauma and hemorrhagic shock.

HYPOTHESIS: The salutary effects of the testosterone receptor antagonist flutamide on the depressed immune and cardiovascular functions after hemorrhage and resuscitation are related to improved endothelial cell function, which can subsequently lead to an increase in organ blood flow, oxygen delivery, and tissue oxygen consumption. DESIGN, INTERVENTIONS, AND MAIN OUTCOME MEASURES: Male adult rats underwent a 5-cm midline laparotomy (ie, trauma) and were bled to and maintained at a mean systemic arterial pressure of 40 mm Hg until 40% maximal blood-out volume was returned in the form of Ringer lactate). The animals were then resuscitated with 4 times the total volume of shed blood with Ringer lactate for 60 minutes. Flutamide (25 mg/kg) or an equivalent volume of the vehicle propanediol was injected subcutaneously 15 minutes before the end of resuscitation. At 20 hours after resuscitation, aortic rings (approximately 2.5 mm in length) were isolated and mounted in an organ chamber. Dose responses for an endothelium-dependent vasodilator (acetylcholine chloride) and endothelium-independent vasodilator (nitroglycerine) were determined. Organ blood flow was measured using strontium 85-labeled microspheres. Total hemoglobin and oxygen content in the femoral artery and portal, hepatic, and renal veins were determined. Oxygen delivery and consumption in liver, small intestine, and kidneys were calculated. RESULTS: Administration of flutamide after trauma-hemorrhage attenuated the depressed endothelial function. Furthermore, flutamide treatment restored the reduced blood flow and oxygen delivery and consumption in all organs tested after trauma-hemorrhage and resuscitation. CONCLUSION: Flutamide appears to be a useful adjunct for improving vascular endothelial function and regional hemodynamics after trauma-hemorrhage and resuscitation.

Acetylcholine↗

PubMed2001

The role of adrenomedullin in producing differential hemodynamic responses during sepsis.

Although the hemodynamic response to polymicrobial sepsis is characterized by an early, hyperdynamic phase followed by a late, hypodynamic phase, the factors responsible for producing the transition from the hyperdynamic to the hypodynamic stage are not fully understood. The failure to recognize or prevent this transition may lead to progressive deteriorations in cell and organ functions and ultimately result in multiple organ failure. Despite the fact that several vasoactive mediators (i.e., nitric oxide, prostacyclin, calcitonin gene-related peptide) have been implicated in producing cardiovascular alterations during sepsis, recent studies have indicated that adrenomedullin (AM), a novel vasodilatory peptide, plays an important role in initiating the hyperdynamic response during the early stage of polymicrobial sepsis. In addition, the reduced vascular responsiveness appears to be responsible for producing the transition from the early, hyperdynamic phase to the late, hypodynamic phase of sepsis. Moreover, modulation of AM vascular responsiveness reduces sepsis-induced mortality. In this review the physiological effects of AM, mechanisms of its action, and regulation of its production under various pathophysiological conditions will be discussed. Furthermore, the role of AM in producing the biphasic hemodynamic responses observed during polymicrobial sepsis and approaches for pharmacologically modulating vascular responsiveness and hemodynamic stability under such conditions will be described.

Adrenomedullin↗

PubMed2001

DHEA: a novel adjunct for the treatment of male trauma patients.

Despite significant advances in the management of trauma victims, traumatic injury with the ensuing sepsis and multiple organ failure remains the leading cause of death between the ages of 18 and 44 in the USA. Recently, interest in the clinically and experimentally observed gender dimorphic response to traumatic injury has led to the possibility of modulating cell and organ functions following trauma and hemorrhagic shock by the administration of sex steroids. Here, we review the effects of the adrenal steroid dehydroepiandrosterone (DHEA), a precursor of sex steroid synthesis, on organ and immune functions following trauma-hemorrhage, and its potential as a novel therapy for improving the depressed cell and organ functions in trauma patients.

Adjuvants, Immunologic↗

PubMed2001

Continuous resuscitation after hemorrhage and acute fluid replacement improves cardiovascular responses.

BACKGROUND: Although acute fluid replacement after trauma and severe hemorrhage remains the cornerstone in the management of trauma victims, it remains unknown whether continuous resuscitation after trauma-hemorrhage and acute fluid replacement produces salutary effects on cardiovascular function and reduces proinflammatory cytokine release. METHODS: Adult male rats underwent laparotomy (ie, soft tissue trauma) and were bled to and maintained at a mean arterial pressure of 40 mm Hg until 40% of the shed blood volume was returned in the form of Ringer's lactate (RL). The animals were then resuscitated with 4 times the volume of shed blood with RL for 60 minutes, followed by continuous resuscitation with RL at 5 mL/h/kg for 48 hours after the acute fluid replacement. At 48 hours after hemorrhage, mean arterial pressure, cardiac output, and left ventricular contractility parameters, such as the maximal rates of ventricular pressure increase (+dP/dt(max)) and decrease (-dP/dt(max)), were determined. Microvascular blood flow in the intestine and kidney was assessed by laser Doppler flowmetry. In addition, plasma levels of TNF-alpha were assayed by enzyme-linked immunosorbent assay. RESULTS: The mean arterial pressure and cardiac output were decreased by 34% and 18%, respectively, at 48 hours after hemorrhage and acute resuscitation. Continuous resuscitation, however, markedly improved these parameters. Similarly, +dP/dt(max) and -dP/dt(max) decreased significantly after hemorrhage and acute fluid replacement but was restored to sham values after continuous resuscitation. Microvascular blood flow in the gut and kidneys was decreased after hemorrhage and acute resuscitation by 34% and 35%, respectively. However, intestinal and renal perfusion was maintained at the sham levels at 48 hours after continuous resuscitation. In addition, the upregulated TNF-alpha after acute resuscitation alone was reduced after continuous resuscitation. CONCLUSIONS: Continuous resuscitation after acute fluid replacement appears to be a useful approach for restoring and maintaining cardiovascular function and organ perfusion after trauma and severe hemorrhage.

Acute Disease↗

PubMed2001

Inhibition of Fas signaling prevents hepatic injury and improves organ blood flow during sepsis.

BACKGROUND: Fas/Fas ligand (FasL) system is one of the major pathways triggering apoptosis that has been shown to play an important role in development and pathogenesis of various diseases including liver and gastrointestinal diseases. Studies indicate that FasL deficiency provides a survival advantage in mice subjected to polymicrobial sepsis. However, the extent to which Fas/FasL contributes to organ injury during sepsis is unclear. Thus, the aim of this study was to determine whether in vivo administration of a Fas-signaling inhibitor during sepsis preserves organ function. METHODS: Male adult C3H/HeN mice were subjected to cecal ligation and puncture (CLP) or sham CLP (sham). Twelve hours after CLP, mice received either Fas-receptor fusion protein (FasFP) (200 microg/kg body weight) or the saline vehicle. Twenty-four hours after the onset of sepsis, cardiac output and organ blood flow were measured with radioactive microspheres. Plasma levels of alanine aminotransferase, aspartate aminotransferase, and lactate dehydrogenase were assessed as indexes of liver damage. Changes in systemic cytokines were measured by enzyme-linked immunosorbent assay. RESULTS. The data indicate that although cardiac output and organ blood flow in the liver, intestine, kidneys, spleen, and heart decreased markedly at 24 hours after CLP, treatment with FasFP maintained the measured hemodynamic parameters and improved hepatic, intestinal, and heart blood flow (P <.05) and partially restored spleen and renal blood flow. Moreover, FasFP treatment markedly attenuated the systemic rise in alanine aminotransferase, aspartate aminotransferase, lactate dehydrogenase, and interleukin 10 (P <.05). CONCLUSIONS: These results not only indicate that there is a role for Fas/FasL-mediated processes in the induction of organ injury but suggest that inhibition of Fas/FasL pathway may represent a novel therapeutic modality for maintaining organ perfusion and preventing liver injury during sepsis.

Alanine Transaminase↗

PubMed2001

Adrenal insufficiency during the late stage of polymicrobial sepsis.

OBJECTIVES: Although studies have indicated that adrenal insufficiency occurs after severe trauma and hemorrhagic shock, it remains controversial whether adrenal function is depressed during the late stage of polymicrobial sepsis. DESIGN: Prospective, controlled animal study. SETTING: A university research laboratory. SUBJECTS: Male rats (275-325 g) were subjected to polymicrobial sepsis by cecal ligation and puncture (CLP) or sham operation followed by the administration of normal saline solution. MEASUREMENTS AND MAIN RESULTS: Systemic blood samples were taken at 20 hrs after CLP (i.e., a late stage of sepsis) or sham operation to measure plasma levels of corticosterone and corticotropin as well as adrenal contents of corticosterone. Additional groups of animals were utilized to examine corticotropin-stimulated plasma corticosterone release as well as adrenal levels of cyclic adenosine monophosphate (cAMP, the second messenger of corticotropin action). The results indicate that despite a 75% (p < .05) higher concentration in plasma corticotropin at 20 hrs after the onset of sepsis, plasma corticosterone levels were similar to those in sham-operated animals. In addition, adrenal contents of corticosterone were reduced by 42% (p < .05) in septic animals. Moreover, the plasma corticosterone and adrenal cAMP responses to corticotropin were reduced by 53% and 27% (p < .05), respectively, at 20 hrs after CLP. CONCLUSIONS: These findings suggest that, despite high plasma levels of endogenous corticotropin, adrenal dysfunction, as indicated by the reduction of corticotropin-induced plasma corticosterone release and adrenal contents of cAMP as well as the decreased adrenal levels of corticosterone, occurs during the late stage of polymicrobial sepsis. Therefore, the recognition of adrenal insufficiency and interventions to improve adrenal responsiveness may be beneficial in improving the outcome during late sepsis.

Adrenal Glands↗

PubMed2001

Glycine attenuates hepatocellular depression during early sepsis and reduces sepsis-induced mortality.

OBJECTIVES: To determine whether administration of glycine, a nonessential amino acid, early after the onset of polymicrobial sepsis has any beneficial effects on hepatocellular function and the survivability of septic animals and, if so, whether the beneficial effects of glycine are associated with down-regulation of proinflammatory cytokine tumor necrosis factor-alpha production. DESIGN: Prospective, controlled, and randomized animal study. SETTING: A university research laboratory. SUBJECTS: Male adult rats were subjected to polymicrobial sepsis by cecal ligation and puncture or sham operation followed by the administration of normal saline solution. MEASUREMENTS AND MAIN RESULTS: At 1 hr after cecal ligation and puncture, glycine (0.6 mmol/kg) or vehicle (normal saline solution) was administered intravenously over 15 mins. At 5 hrs after cecal ligation and puncture (i.e., early stage of sepsis), hepatocellular function (i.e., the maximal velocity and efficiency of in vivo indocyanine green clearance) was determined and hepatocyte injury was assessed by measuring plasma concentrations of alpha-gluthathione S-transferase. Serum tumor necrosis factor-alpha was measured by enzyme-linked immunosorbent assay. In additional animals, the necrotic cecum was excised at 20 hrs after cecal ligation and puncture, the peritoneal cavity was irrigated with saline, and the midline incision was closed in layers. Mortality was monitored for 10 days thereafter. The results indicate that hepatocellular function was depressed in the early stage of sepsis (i.e., 5 hrs after cecal ligation and puncture) as indicated by significant decreases in both maximal velocity and transport efficiency of in vivo indocyanine green clearance. Plasma concentrations of alpha-gluthathione S-transferase and tumor necrosis factor-alpha were elevated significantly at that interval after cecal ligation and puncture. Administration of glycine 1 hr after cecal ligation and puncture, however, increased maximal velocity and maximal efficiency by 60% and 101% (p <.05), respectively. Glycine administration in septic animals decreased alpha-gluthathione S-transferase and tumor necrosis factor-alpha by 43% and 80% (p <.05). In addition, glycine treatment decreased the mortality rate from 50% to 0% (p <.05) at 10 days after cecal ligation and puncture and cecal excision. CONCLUSIONS: It appears that the beneficial effect of glycine on hepatocyte function and integrity in sepsis may be mediated via down-regulation of tumor necrosis factor-alpha. Because administration of glycine attenuated hepatocellular depression and injury during early sepsis and decreased sepsis-induced mortality rates, this amino acid appears to be a useful adjunct for maintaining cellular functions and preventing lethality from polymicrobial sepsis.

Analysis of Variance↗

PubMed2001

Evolution of an immune suppressive macrophage phenotype as a product of P38 MAPK activation in polymicrobial sepsis.

Studies indicate that polymicrobial sepsis in humans and animals is characterized by a biphasic response, which is dominated early by proinflammation, but over time develops into a state of generalized anti-inflammation (depressed Th1 cell response and decreased macrophage (M0) capacity to release proinflammatory cytokines). However, with respect to the macrophage, it remains unknown what mechanism(s) controls this change. In this regard it is well documented that the p38 mitogen activated protein kinase pathway (MAPK) plays a central role in the regulation of Mphi functions. However, the contribution of p38 MAPK activation to the loss of these Mphi functions in polymicrobial septic animals remains unknown. To determine this we induced polymicrobial sepsis in C3H/HeN male mice using cecal ligation and puncture (CLP). Twenty-four hours post-CLP, during the late, immune-suppressed stage of sepsis, splenic and peritoneal Mphi were harvested, stimulated with lipopolysaccharide (LPS), and the activation of p38 MAPK assessed. In Mphi from CLP mice, p38 MAPK activity was markedly increased. To determine the extent that these changes in p38 MAPK had an impact on Mphi immune function, cells were pretreated with 10 microM of the p38 MAPK inhibitor, SB203580, or with DMSO vehicle, and subsequently stimulated with LPS. IL-10, IL-6, IL-12, and nitric oxide release was determined. Our results indicate that with LPS stimulation alone, there was a marked increase in the release of the anti-inflammatory mediator, IL-10 after CLP. Alternatively, proinflammatory IL-12 and IL-6 release was suppressed. Treatment with SB203580 suppressed the increase in IL-10 release seen after CLP, while partially restoring IL-12 secretion. IL-6 release was partially restored only in splenic macrophages treated with SB203580. To the extent that these in vitro findings could be translated to an in vivo setting, we assessed the in vivo effects of p38 MAPK inhibition on survival. Mice were given 100 mg of SB203580/kg body weight or saline vehicle (intraperitoneal) either immediately post-CLP or 12 h post-CLP. Delayed administration of SB203580 significantly improved survival, while also preventing the increased NO and IL-10 release and improving IL-12 release by macrophages. These results suggest that p38 MAPK pathway plays a critical role in the induction of an immune-suppressive macrophage phenotype, and that inhibition of p38 MAPK markedly improves survival following polymicrobial sepsis.

Animals↗