Biomedical subjects

I Garcia

Publications and source records attributed to I Garcia.

At least 73 records · Page 4Linked to original sources

PubMed1999

Lipid peroxidation and antioxidant defenses in cystic fibrosis patients.

Lipid peroxidation biomarkers and antioxidant status were measured in 76 cystic fibrosis (CF) patients and compared to 40 control subjects. Univariate and multivariate statistics were performed in this study. Results showed that indicators of lipid peroxidation were higher in CF patients than in controls; thiobarbituric acid reactants and autoantibodies against oxidized low-density lipoproteins were significantly increased in CF patients. Red blood cells and whole blood glutathione peroxidase activities were lower in CF patients than in controls. No difference in red blood cell superoxide dismutase activity was observed. Measured concentration of glutathione peroxidase in plasma showed a higher mean value of this protein in CF patients than in controls. Retinol, alpha-tocopherol and beta-carotene concentrations were all reduced in CF patients as compared to controls; this was particularly pronounced for beta-carotene. The decreased alpha-tocopherol concentration was associated with higher percent hemolysis in CF patients. The results of this study indicate that both lipid peroxidation biomarkers and antioxidant status were disturbed in CF patients, despite medical assistance. Measures of oxidative stress parameters, such as thiobarbituric acid reactants, glutathione peroxidase, and beta-carotene concentrations can be considered as significant indicators to discriminate CF patients and control subjects.

Adolescent↗

PubMed1998

Multiple forms of angiostatin induce apoptosis in endothelial cells.

Angiostatin is a circulating inhibitor of angiogenesis generated by proteolytic cleavage of plasminogen. In this study we have used recombinant human and murine angiostatins (kringles 1-4) as well as native human angiostatin (prepared by elastase digestion of plasminogen [kringles 1-3] or by plasmin autocatalysis in the presence of a free sulfhydryl donor [kringles 1-4]). We report that angiostatin reduces endothelial cell number in a 4-day proliferation assay without affecting cell cycle progression into S-phase (as determined by bromodeoxyuridine labeling). This suggested that the reduction in cell number in the proliferation assay might in part be due to cytotoxicity. This was confirmed by the observation that ethidium homodimer incorporation (a measure of plasma membrane integrity) into endothelial cells was increased by angiostatin in a manner similar to that seen with tumor necrosis factor- (TNF-) and transforming growth factor-beta1 (TGF-beta1), both of which induce apoptosis in endothelial cells. In contrast to TNF- and TGF-beta1, angiostatin did not induce cytotoxicity in human MRC-5 fibroblast, rat smooth muscle, canine MDCK epithelial, or murine B16-F10 melanoma cell lines. Angiostatin-induced apoptosis was confirmed by endothelial cell nuclear acridine orange incorporation as well as by annexin V and TUNEL staining. These in vitro findings point to endothelial cell apoptosis as a mechanism for the antiangiogenic effect of angiostatin in vivo.

Angiostatins↗

PubMed1998

Diva, a Bcl-2 homologue that binds directly to Apaf-1 and induces BH3-independent cell death.

We have identified and characterized Diva, which is a novel regulator of apoptosis. Sequence analysis revealed that Diva is a member of the Bcl-2 family of proteins containing Bcl-2 homology domain 1, 2, 3, and 4 (BH1, BH2, BH3, and BH4) regions and a carboxyl-terminal hydrophobic domain. The expression of Diva mRNA was detected in multiple embryonic tissues but was restricted to the ovary and testis in adult mice. The expression of Diva promoted the death of 293T, Ramsey, and T47D cells as well as that of primary sensory neurons, indicating that Diva is a proapoptotic protein. Significantly, Diva lacks critical residues in the conserved BH3 region that mediate the interaction between BH3-containing proapoptotic Bcl-2 homologues and their prosurvival binding partners. Consistent with this, Diva did not bind to cellular Bcl-2 family members including Bcl-2, Bcl-XL, Bcl-w, Mcl-1, and A1/Bfl-1. Furthermore, mutants of Diva lacking the BH3 region fully retained their proapoptotic activity, confirming that Diva promotes apoptosis in a BH3-independent manner. Significantly, Diva interacted with a viral Bcl-2 homologue (vBcl-2) encoded by the Kaposi's sarcoma-associated herpesvirus. Consistent with these associations, apoptosis induced by Diva was inhibited by vBcl-2 but not by Bcl-XL. Importantly, Diva interacted with Apaf-1, an adapter molecule that activates caspase-9, a central death protease of the apoptotic pathway. The expression of Diva inhibited the binding of Bcl-XL to Apaf-1, as determined by immunoprecipitation assays. Thus, Diva represents a novel type of proapoptotic Bcl-2 homologue that promotes apoptosis independently of the BH3 region through direct binding to Apaf-1, thus preventing Bcl-XL from binding to the caspase-9 regulator Apaf-1.

Amino Acid Sequence↗

PubMed1998

Protein turnover in skeletal muscle of tumour-bearing transgenic mice overexpressing the soluble TNF receptor-1.

The implantation of the Lewis lung carcinoma (a fast-growing mouse tumour that induces cachexia) to both wild-type and transgenic mice for the soluble TNF receptor type I protein (sTNF-R1) resulted in a considerable loss of carcass weight in both groups. However, while in the wild-type mice there was a loss of both fat and muscle, in the transgenic mice muscle waste was not affected to the same extent as in the wild-type group. Muscle waste in wild-type mice was accompanied by an increase in the fractional rate of protein degradation, while no changes were observed in protein synthesis. The result was a decreased rate of protein accumulation which accounted for the muscle weight loss observed as a result of the tumour burden. In contrast, transgenic mice did not have such low rates of protein accumulation after tumour implantation. The increase in protein degradation in the tumour-bearing transgenic mice was accompanied by a similar increase in protein synthesis which compensated for the loss of muscle protein by degradation. Both tumour-bearing groups showed an enhanced expression of ubiquitin and proteasome C8 subunit genes, all of them related to the activation of the ATP-dependent proteolytic system in skeletal muscle. It is suggested that TNF may, in part, be responsible for the loss of protein in skeletal muscle of tumour-bearing mice.

Animals↗

PubMed1998

Genes from mycoparasitic fungi as a source for improving plant resistance to fungal pathogens.

Disease resistance in transgenic plants has been improved, for the first time, by the insertion of a gene from a biocontrol fungus. The gene encoding a strongly antifungal endochitinase from the mycoparasitic fungus Trichoderma harzianum was transferred to tobacco and potato. High expression levels of the fungal gene were obtained in different plant tissues, which had no visible effect on plant growth and development. Substantial differences in endochitinase activity were detected among transformants. Selected transgenic lines were highly tolerant or completely resistant to the foliar pathogens Alternaria alternata, A. solani, Botrytis cinerea, and the soilborne pathogen Rhizoctonia solani. The high level and the broad spectrum of resistance obtained with a single chitinase gene from Trichoderma overcome the limited efficacy of transgenic expression in plants of chitinase genes from plants and bacteria. These results demonstrate a rich source of genes from biocontrol fungi that can be used to control diseases in plants.

Base Sequence↗

PubMed1998

Mtd, a novel Bcl-2 family member activates apoptosis in the absence of heterodimerization with Bcl-2 and Bcl-XL.

We have identified and characterized Mtd, a novel regulator of apoptosis. Sequence analysis revealed that Mtd is a member of the Bcl-2 family of proteins containing conserved BH1, BH2, BH3, and BH4 regions and a carboxyl-terminal hydrophobic domain. In adult tissues, Mtd mRNA was predominantly detected in the brain, liver, and lymphoid tissues, while in the embryo Mtd mRNA was detected in the liver, thymus, lung, and intestinal epithelium. Expression of Mtd promoted the death of primary sensory neurons, 293T cells and HeLa cells, indicating that Mtd is a proapoptotic protein. Unlike all other known death agonists of the Bcl-2 family, Mtd did not bind significantly to the survival-promoting proteins Bcl-2 or Bcl-XL. Furthermore, apoptosis induced by Mtd was not inhibited by Bcl-2 or Bcl-XL. A Mtd mutant with glutamine substitutions of highly conserved amino acids in the BH3 domain retained its ability to promote apoptosis, further indicating that Mtd does not promote apoptosis by heterodimerizing with Bcl-2 or Bcl-XL. Mtd-induced apoptosis was not blocked by broad range synthetic caspase inhibitors z-VAD-fmk or a viral protein CrmA. Mtd is the first example of a naturally occurring Bcl-2 family member that can activate apoptosis independently of heterodimerization with survival-promoting Bcl-2 and Bcl-XL.

Amino Acid Sequence↗

PubMed1998

Both TNF receptors are required for direct TNF-mediated cytotoxicity in microvascular endothelial cells.

The conditions under which tumor necrosis factor-alpha (TNF) induces apoptosis in primary microvascular endothelial cells (MVEC) were investigated. In the absence of sensitizing agents, TNF induced apoptosis after 3 days of incubation in confluent MVEC. In contrast, upon addition of the transcriptional inhibitor actinomycin D (Act. D), confluence was no longer required and apoptosis occurred already after 16 h. To assess the role of either TNF receptor (TNFR) type in apoptosis, MVEC isolated from mice genetically deficient in TNFR1 (Tnfr1o mice) or TNFR2 (Tnfr2o mice) were incubated with TNF in the presence or absence of Act. D. Under sensitized conditions, Tnfr2o MVEC were lysed like controls, whereas Tnfr1o MVEC were completely resistant, indicating an exclusive role for TNFR1. In contrast, in the absence of Act. D, confluent monolayers of wild-type cells were lysed by TNF, but both Tnfr1o and Tnfr2o MVEC were resistant to TNF-mediated toxicity, indicating a requirement for both TNFR types. Overexpression of the anti-apoptotic protein bcl-xL in MVEC led to a protection against the direct, but not the sensitized cytotoxicity of TNF. In conclusion, in pathophysiologically relevant conditions, both TNFR appear to be required for TNF-induced apoptosis in MVEC.

Animals↗

PubMed1998

Trough to peak ratio of once-daily lisinopril and twice-daily captopril in patients with essential hypertension.

The objective of this study was to assess the antihypertensive effect and the trough to peak (T:P) ratio of lisinopril and captopril, in patients with essential hypertension. After 2 weeks of placebo, 69 of 115 eligible patients had office diastolic blood pressure (DBP) between 90 and 114 mm Hg and daytime average DBP above 85 mm Hg during a 25-h ambulatory BP monitoring (ABPM) and were randomised to receive lisinopril (20 mg once daily) or captopril (50 mg twice daily) for 4 weeks. Office and ambulatory BP were then repeated. Indices of 24-h BP and T:P ratios were calculated and compared. Both drugs significantly reduced both office and ambulatory BP. The final BP obtained with lisinopril was less than with captopril. On office measurement, 75% of the patients treated with lisinopril and 44% on captopril were controlled (P < 0.001), but responses by ABPM were not significantly different. T:P ratios calculated in all patients were 0.75 and 0.66 for lisinopril and captopril respectively, but in patients who responded to each drug the corresponding ratios were 0.78 and 0.73. In conclusion both 20 mg once-daily lisinopril and 50 mg captopril twice-daily achieve a favourable T:P ratio in patients with essential hypertension.

Adult↗

PubMed1998

Clinical, virological, and histologic evolution of hepatitis C virus infection in liver transplant recipients.

We designed a prospective study to assess the time course and evolution of hepatitis C virus (HCV) infection in 152 patients who underwent a liver transplantation (LT) in our institution. Forty-four recipients (29%) were infected by HCV after transplantation: 40 who developed recurrent infection after LT and four who acquired infection during or after LT. No differences were found in survival actuarial rates at 1, 2, and 4 years after transplantation for patients infected by HCV vs. noninfected ones. Graft hepatitis occurred in 66% of HCV-infected recipients: 18 developed chronic active hepatitis (10 of them with intense fibrosis) and 2 developed cirrhosis during the follow-up. Infection by the HCV-1b genotype was found in 79% of the infected recipients and in 100% of those in whom histologic evolution was worst. Fourteen grafts were lost in 44 HCV-infected recipients, in comparison with 12 in 108 HCV-negative patients (P = .007), mostly because of chronic rejection. HCV infection did not affect life expectancy in the midterm follow-up for LT patients. However, it was often associated with the occurrence of early and severe graft hepatitis and with a higher incidence of graft loss due to chronic rejection.

Adult↗

PubMed1998

Biochemical assessment of the nutritional status of cystic fibrosis patients treated with pancreatic enzyme extracts.

We examined the protein and fat nutritional status of 65 cystic fibrosis patients aged 4-26 y (x +/- SD: 11.2 +/- 5.6 y). Patients were treated with pancreatic enzyme extracts to improve nutrient absorption; in addition, most patients were supplemented with vitamins A and E. Results were compared with those in a control group of 39 subjects aged 5-29 y (x: 14.3 +/- 5.6 y) with no digestive diseases or nutritional deficiencies. Protein determination showed low albumin concentrations in 42% of the cystic fibrosis patients and decreased blood concentrations of retinol binding protein in 12% of the patients. Lipoprotein components were characterized by decreased cholesterol concentrations in 25% of the cystic fibrosis group. Also, mean concentrations of apolipoprotein A-I were significantly lower in the cystic fibrosis group than in control subjects. The results of fatty acid status, expressed in relative (%) and absolute (mg/L) values, showed concentrations of essential fatty acids, represented by linoleic and arachidonic acids, to be significantly decreased in cystic fibrosis patients; this decrease was markedly significant for fatty acid status expressed in absolute values, especially in the cholesteryl ester subfraction. Serum retinol and alpha-tocopherol concentrations were lowered by 8% and 46% in cystic fibrosis patients and control subjects, respectively: retinol, 1.80 +/- 0.50 and 2.37 +/- 0.60 micromol/L, P < 0.001, and alpha-tocopherol, 18.1 +/- 8.7 and 25.7 +/- 5.0 micromol/L, P < 0.001. In conclusion, despite regular treatment with pancreatic enzyme replacements, neither protein nor fat malnutrition in cystic fibrosis patients was completely corrected.

Adolescent↗

PubMed1998

Dithiocarbamates enhance tumor necrosis factor-alpha production by rabbit alveolar macrophages, despite inhibition of NF-kappaB.

The tissue-fixed macrophage (Mphi) plays a key role in coordinating the excessive inflammatory response following shock or sepsis. Reactive oxygen intermediates have been recently described as second messengers involved in signal transduction in these cells, including the activation of the transcription factors NF-kappaB and AP-1. The dithiocarbamates are potent antioxidants that inhibit NF-kappaB activation. We postulated that dithiocarbamates would inhibit Mphi activation via inhibition of NF-kappaB. Rabbit alveolar Mphi were obtained by bronchoalveolar lavage and exposed to either pyrrolidine dithiocarbamate (PDTC) or diethyl dithiocarbamate (DDTC) followed by stimulation with LPS (10 ng/mL). Supernatants were analyzed for TNF and prostaglandin E2, (PGE2) and F2-isoprostane (ISP), a marker of membrane lipid peroxidation, production at 18 h. PDTC and DDTC significantly enhanced production of TNF while inhibiting PGE2 and ISP production compared with LPS alone (p < .05). Northern blots revealed increased mRNA for TNF after pretreatment with PDTC, compared with LPS alone. Western blots and oligonucleotide gel shifts of nuclear proteins revealed inhibition of NF-kappaB activation by both PDTC and DDTC. AP-1 activity was shifted to earlier time points by PDTC pretreatment. These results demonstrate transcriptional and functional enhancement of TNF production despite inhibition of NF-kappaB activation. This may be due in part to a loss of autocrine feedback inhibition by PGE2 and enhancement of AP-1 activity. On the basis of these results, we conclude NF-kappaB may be necessary but, in contrast to prior analyzes, is not sufficient for optimal response of the alveolar Mphi to endotoxin.

Animals↗

PubMed1998

Metabolic-cytokine responses to a second immunological challenge with LPS in mice with T. gondii infection.

Injection of 10 cysts of Toxoplasma gondii (Me49 strain) into Swiss Webster mice results in 1) an acute phase of infection lasting for 2-3 wk, characterized by weight loss, and 2) a chronic phase in which surviving mice show either partial weight recovery (Gainers) or persistent, although stable, cachexia (Nongainers). In response to a second immunological stimulation with lipopolysaccharide (LPS) in the chronic phase of the infection, it is shown that 1) the increase in energy expenditure was more prolonged in both groups of infected mice than in controls, 2) the intensity and duration of hypophagia were also differently affected with Nongainers > Gainers > controls, and 3) the infected mice had higher serum levels of tumor necrosis factor-alpha (TNF-alpha) and interleukin (IL)-10 and a lower ratio of IL-10 to TNF-alpha than controls. In contrast, serum IL-4 increased to the same level in all three groups. Evaluation of the permeability of the blood-brain barrier by intravenous injection of Evans blue revealed a marked staining in the brain of only the infected Nongainers. Taken together, these results indicate that, in mice with chronic toxoplasmosis, a second nonspecific challenge (with LPS) exacerbates the hypophagic and hypermetabolic states, the latter being associated with hyperresponsiveness in TNF-alpha and IL-10 production. Furthermore, the greater exacerbation of the hypophagic state in mice showing persistent cachexia may be due to a preexisting higher permeability of the blood-brain barrier, which would allow a greater access of plasma-borne cytokines and/or other neuroimmunologically active substances to the central nervous system.

Animals↗

PubMed1997

TWEAK, a new secreted ligand in the tumor necrosis factor family that weakly induces apoptosis.

The members of the tumor necrosis factor (TNF) family play pivotal roles in the regulation of the immune system. Here we describe a new ligand in this family, designated TWEAK. The mouse and human versions of this protein are unusually conserved with 93% amino acid identity in the receptor binding domain. The protein was efficiently secreted from cells indicating that, like TNF, TWEAK may have the long range effects of a secreted cytokine. TWEAK transcripts were abundant and found in many tissues, suggesting that TWEAK and TRAIL belong to a new group of widely expressed ligands. Like many members of the TNF family, TWEAK was able to induce interleukin-8 synthesis in a number of cell lines. The human adenocarcinoma cell line, HT29, underwent apoptosis in the presence of both TWEAK and interferon-gamma. Thus, TWEAK resembles many other TNF ligands in the capacity to induce cell death; however, the fact that TWEAK-sensitive cells are relatively rare suggests that TWEAK along with lymphotoxins alpha/beta and possibly CD30L trigger death via a weaker, nondeath domain-dependent mechanism.

Adenocarcinoma↗

PubMed1997

Subcellular localization and purification of a p-hydroxyphenylpyruvate dioxygenase from cultured carrot cells and characterization of the corresponding cDNA.

p-Hydroxyphenylpyruvate dioxygenase catalyses the transformation of p-hydroxyphenylpyruvate into homogentisate. In plants this enzyme has a crucial role because homogentisate is the aromatic precursor of all prenylquinones. Furthermore this enzyme was recently identified as the molecular target for new families of potent herbicides. In this study we examine precisely the localization of p-hydroxyphenylpyruvate dioxygenase activity within carrot cells. Our results provide evidence that, in cultured carrot cells, p-hydroxyphenylpyruvate dioxygenase is associated with the cytosol. Purification and SDS/PAGE analysis of this enzyme revealed that its activity is associated with a polypeptide of 45-46 kDa. This protein specifically cross-reacts with an antiserum raised against the p-hydroxyphenylpyruvate dioxygenase of Pseudomonas fluorescens. Gel-filtration chromatography indicates that the enzyme behaves as a homodimer. We also report the isolation and nucleotide sequence of a cDNA encoding a carrot p-hydroxyphenylpyruvate dioxygenase. The nucleotide sequence (1684 bp) encodes a protein of 442 amino acid residues with a molecular mass of 48094 Da and shows specific C-terminal regions of similarity with other p-hydroxyphenylpyruvate dioxygenases. This cDNA encodes a functional p-hydroxyphenylpyruvate dioxygenase, as evidenced by expression studies with transformed Escherichia coli cells. Comparison of the N-terminal sequence of the 45-46 kDa polypeptide purified from carrot cells with the deduced peptide sequence of the cDNA confirms that this polypeptide supports p-hydroxyphenylpyruvate dioxygenase activity. Immunodetection studies of the native enzyme in carrot cellular extracts reveal that N-terminal proteolysis occurs during the process of purification. This proteolysis explains the difference in molecular masses between the purified protein and the deduced polypeptide.

4-Hydroxyphenylpyruvate Dioxygenase↗

PubMed1997

An early and massive wave of germinal cell apoptosis is required for the development of functional spermatogenesis.

Transgenic mice expressing high levels of the BclxL or Bcl2 proteins in the male germinal cells show a highly abnormal adult spermatogenesis accompanied by sterility. This appears to result from the prevention of an early and massive wave of apoptosis in the testis, which occurs among germinal cells during the first round of spermatogenesis. In contrast, sporadic apoptosis among spermatogonia, which occurs in normal adult testis, is not prevented in adult transgenic mice. The physiological early apoptotic wave in the testis is coincident, in timing and localization, with a temporary high expression of the apoptosis-promoting protein Bax, which disappears at sexual maturity. The critical role played by the intracellular balance, probably hormonally controlled, of the BclxL and Bax proteins (Bcl2 is apparently not expressed in normal mouse testis) in this early apoptotic wave is shown by the occurrence of a comparable testicular syndrome in mice defective in the bax gene. The apoptotic wave appears necessary for normal mature spermatogenesis to develop, probably because it maintains a critical cell number ratio between some germinal cell stages and Sertoli cells, whose normal functions and differentiation involve an elaborate network of communication.

Animals↗

PubMed1997

Transgenic mice expressing soluble tumor necrosis factor-receptor are protected against bone loss caused by estrogen deficiency.

To evaluate the role of tumor necrosis factor (TNF alpha) in bone loss resulting from estrogen deficiency, the effects of ovariectomy were explored in six-month-old transgenic mice expressing high blood levels of a soluble TNF receptor type I (sTNFR1)-FcIgG3 fusion protein, which neutralizes TNF alpha, and in their nontransgenic littermates used as controls. These transgenic mice were identical to control mice in bone mass (evaluated by bone mineral density and content) and strength. 12 weeks after ovariectomy, the decrease in bone mass and increase in osteocalcin (marker of bone turnover) found in control mice were not observed in transgenic mice, which were not different from sham-operated mice, transgenic or not. This observation suggests a critical role for TNF alpha in the pathogenesis of bone loss induced by estrogen deficiency, a common cause of morbidity in postmenopausal women.

Animals↗

PubMed1997

Geographic variation in the utilization of esophagoscopy and bronchoscopy in head and neck cancer.

OBJECTIVE: To determine the extent to which esophagoscopy and bronchoscopy are being used in various regions of the United States in the initial examination of patients with head and neck cancer. DESIGN: Population-based study derived from Medicare claims data and information from the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) Program. SETTING: Five SEER areas (San Francisco, Calif; Connecticut; Seattle, Wash; Iowa; and Detroit, Mich). PARTICIPANTS: The cohort included 1410 Medicare patients with squamous cell carcinoma of the oral cavity, oropharynx, hypopharynx, or larynx diagnosed between March 1, 1991, and December 31, 1993, in the 5 SEER areas. MAIN OUTCOME MEASURE: Rates of esophagoscopy and bronchoscopy according to SEER area. RESULTS: The proportion of patients who underwent esophagoscopy ranged from 12.9% (San Francisco) to 39.8% (Detroit) for patients with local cancer and from 22.2% (San Francisco) to 59.7% (Detroit) for patients with regional cancer. The proportion of patients who underwent bronchoscopy ranged from 6.9% (San Francisco) to 32.6% (Detroit) for patients with local cancer and from 12.8% (San Francisco) to 50.7% (Detroit) for patients with regional cancer. After controlling for differences in age, sex, race, tumor site, tumor grade, comorbidity, and socioeconomic status, SEER area remained independently associated with esophagoscopy and bronchoscopy (both P < .001). CONCLUSIONS: There is substantial geographic variation in the use of esophagoscopy and bronchoscopy as part of the initial examination of patients diagnosed as having head and neck cancer that cannot be explained by differences in patient or tumor characteristics. This variation likely underscores uncertainty and disagreement about the value of endoscopic screening for synchronous tumors. Additional research is required to determine whether routine endoscopic screening increases survival rates or improves quality of life.

Aged↗

PubMed1997

Enteral vitamin E supplementation inhibits the cytokine response to endotoxin.

OBJECTIVE: To evaluate the effect of short-term, high-dose enteral supplementation of 3 different vitamin E derivatives: free alpha-tocopherol (VE), alpha-tocopherol succinate (VES), and alpha-tocopherol acetate (VEA) on macrophage and monocyte activation. DESIGN: Sprague-Dawley rats (weight, 150-200 g) were assigned to 1 of 5 experimental groups: saline (control), ethanol (control), VES (100 mg/kg), VEA (100 mg/kg), or VE (100 mg/kg). Rats underwent oral gavage once per day for 5 days with 0.5 mL of their assigned solution. All vitamin E derivatives were diluted in 75% ethanol. Rats were then killed and whole-blood and peritoneal macrophages were harvested and stimulated with lipopolysaccharide (10 microg/mL) in vitro. Tumor necrosis factor (TNF) production was measured by enzyme-linked immunosorbent assay. Additional serum samples were analyzed for alpha-tocopherol concentration by high-performance lipid chromatography. RESULTS: Whole-blood TNF production was maximal in the control groups after 3 hours of incubation and began to decline by 6 hours. Supplementation with all 3 vitamin E derivatives resulted in suppression of lipopolysaccharide-induced TNF production at both time points when compared with both ethanol and saline controls (P<.05, analysis of variance [ANOVA]). All 3 vitamin E derivatives also resulted in significant inhibition of lipopolysaccharide-induced TNF production by peritoneal macrophages when compared with their ethanol-carrier control but not with the saline control (P<.05, ANOVA). The degree of TNF suppression correlated directly with serum alpha-tocopherol levels. CONCLUSIONS: Our data demonstrate that a short-term, high-dose enteral supplementation of vitamin E can modulate the monocyte and macrophage response to endotoxin. These data, along with other animal studies showing a protective effect of vitamin E treatment in sepsis and ischemia-reperfusion injury, suggest a potential role for vitamin E supplementation in patients at risk of the systemic inflammatory response syndrome.

Animals↗