Plasma tumor necrosis factor-alpha during long-term endotoxemia in awake sheep

1992 ◽  
Vol 73 (5) ◽  
pp. 1831-1837 ◽  
Author(s):  
P. J. Sloane ◽  
T. H. Elsasser ◽  
J. A. Spath ◽  
K. H. Albertine ◽  
M. H. Gee

We used a continuous 12-h infusion of Escherichia coli endotoxin (10 ng.min-1.kg-1) in 10 awake sheep equipped with a lung lymph fistula and vascular catheters to determine the time course of increased plasma tumor necrosis factor-alpha (TNF-alpha) during the infusion and a 12-h postinfusion period. Lung lymph flow increased progressively during the infusion to a peak value averaging 8.6 +/- 2.0 times the baseline flow of 6.3 +/- 1.3 g/h. During the postinfusion period, lung lymph flow remained elevated at three to four times baseline. The lymph-to-plasma protein concentration ratio was unchanged from baseline over 24 h, indicating a dramatic increase in net protein flux across pulmonary microvessels. The TNF-alpha concentration peaked early in the infusion and then declined, despite the continuing presence of endotoxin. Plasma TNF-alpha concentration increased 10-fold (0.33 +/- 0.05 ng/ml at baseline to 3.89 +/- 0.78 ng/ml peak) 2 h into the endotoxin infusion. At the end of the endotoxin infusion, plasma TNF-alpha had decreased to 1.16 +/- 0.19 ng/ml. The circulating TNF-alpha concentration did not correlate with pathophysiology or outcome in these sheep.

1989 ◽  
Vol 66 (3) ◽  
pp. 1448-1454 ◽  
Author(s):  
J. Johnson ◽  
B. Meyrick ◽  
G. Jesmok ◽  
K. L. Brigham

The macrophage-derived cytokine tumor necrosis factor alpha (TNF alpha) has been proposed as the major mediator of endotoxin-induced injury. To examine whether a single infusion of human recombinant TNF alpha (rTNF alpha) reproduces the pulmonary effects of endotoxemia, we infused rTNF alpha (0.01 mg/kg) over 30 min into six chronically instrumented awake sheep and assessed the ensuing changes in hemodynamics, lung lymph flow and protein concentration, and number of peripheral blood and lung lymph leukocytes. In addition, levels of thromboxane B2, 6-ketoprostaglandin F1 alpha, prostaglandin E2, and leukotriene B4 were measured in lung lymph. Pulmonary arterial pressure (Ppa) peaked within 15 min of the start of rTNF alpha infusion [base-line Ppa = 22.0 +/- 1.5 (SE) cmH2O; after 15 min of rTNF alpha infusion, Ppa = 54.2 +/- 5.4] and then fell toward base line. The pulmonary hypertension was accompanied by hypoxemia and peripheral blood and lung lymph leukopenia, both of which persisted throughout the 4 h of study. These changes were followed by an increase in protein-rich lung lymph flow (base-line lymph protein clearance = 1.8 +/- 0.4 cmH2O; 3 h after rTNF alpha infusion, clearance = 5.6 +/- 1.2), consistent with an increase in pulmonary microvascular permeability. Cardiac output and left atrial pressure did not change significantly throughout the experiment. Light-microscopic examination of lung tissue at autopsy revealed congestion, neutrophil sequestration, and patchy interstitial edema. We conclude that rTNF alpha induces a response in awake sheep remarkable similar to that of endotoxemia. Because endotoxin is a known stimulant of TNF alpha production, TNF alpha may mediate endotoxin-induced lung injury.


1995 ◽  
Vol 269 (6) ◽  
pp. G953-G960 ◽  
Author(s):  
M. Mehran ◽  
E. Seidman ◽  
R. Marchand ◽  
C. Gurbindo ◽  
E. Levy

Cytokines, important mediators of inflammation, have been shown to cause disturbances in circulating and hepatic lipid metabolism. Although the intestine plays a major role in dietary fat transport and largely contributes to plasma lipoproteins, the effects of cytokines on intestinal lipid handling remain unknown. In the present study, the modulation of lipid, apoprotein, and lipoprotein synthesis and secretion by tumor necrosis factor-alpha (TNF-alpha) was investigated in Caco-2 cells. Highly differentiated and polarized cells (20 days in culture) were incubated for 20 h with recombinant human TNF-alpha (100-500 ng/ml). No cytotoxic effect of TNF-alpha cells was observed, as indicated by the determinations of Caco-2 cell viability and monolayer transepithelial resistance. Moreover, no differences in cell maturation (sucrase activity) or cell proliferation ([3H]thymidine incorporation and cell cycle analysis) were detected between treated and control cultures. Significant inhibition of lipid secretion by TNF-alpha was observed, with the greatest reduction at 500 ng/ml. TNF-alpha significantly decreased Caco-2 cell secretion of phospholipids (22%), triglycerides (30%), and cholesteryl ester (37%). It also significantly diminished the export of newly synthesized low-density lipoproteins (LDL; 20%) and high-density lipoproteins (HDL; 13%), with a lesser effect on very low-density lipoproteins (VLDL; 3%). The lipid composition of these lipoproteins was minimally affected. De novo synthesis of apo A-I, apo B-100, and apo B-48 was also markedly reduced by TNF-alpha. Sphingomyelinase activity was not increased and cell content of sphingomyelin was not altered, suggesting that inhibitory effects on lipid and apoprotein of TNF-alpha were not mediated by the ceramide pathway. Our results indicate that TNF-alpha may play a role in modulating intestinal lipid metabolism, thus affecting circulating lipoproteins.


1994 ◽  
Vol 14 (10) ◽  
pp. 6561-6569
Author(s):  
L Klampfer ◽  
T H Lee ◽  
W Hsu ◽  
J Vilcek ◽  
S Chen-Kiang

Tumor necrosis factor alpha (TNF-alpha) and interleukin-1 (IL-1) activate transcription of the TSG-6 gene in normal human fibroblasts through a promoter region (-165 to -58) that encompasses an AP-1 and a NF-IL6 site. We show by deletion analysis and substitution mutagenesis that both sites are necessary for activation by TNF-alpha. Activation by IL-1 requires the NF-IL6 site and is enhanced by the AP-1 site. These results suggest that the NF-IL6 and AP-1 family transcription factors functionally cooperate to mediate TNF-alpha and IL-1 signals. Consistent with this possibility, IL-1 and TNF-alpha markedly increase the binding of Fos and Jun to the AP-1 site, and NF-IL6 activates the native TSG-6 promoter. Activation by NF-IL6 requires an intact NF-IL6 site and is modulated by the ratio of activator to inhibitor NF-IL6 isoforms that are translated from different in-frame AUGs. However, the inhibitor isoform can also bind to the AP-1 site and repress AP-1 site-mediated transcription. The finding that the inhibitor isoform antagonizes activation of the native TSG-6 promoter by IL-1 and TNF-alpha suggests that NF-IL6 has a physiologic role in these cytokine responses. Thus, the functionally distinct NF-IL6 isoforms cooperate with Fos and Jun to positively and negatively regulate the native TSG-6 promoter by TNF-alpha and IL-1.


1998 ◽  
Vol 21 (6) ◽  
pp. 638-640 ◽  
Author(s):  
Masaaki ISHIKAWA ◽  
Shu-ichi KANNO ◽  
Motoaki TAKAYANAGI ◽  
Yoshio TAKAYANAGI ◽  
Ken-ichi SASAKI

1992 ◽  
Vol 263 (5) ◽  
pp. E897-E902 ◽  
Author(s):  
M. Beylot ◽  
H. Vidal ◽  
G. Mithieux ◽  
M. Odeon ◽  
C. Martin

Tumor necrosis factor-alpha (TNF-alpha) stimulates hepatic lipogenesis. Therefore, it could play a role in the control of ketogenesis. To test this hypothesis, we measured simultaneously free fatty acids (FFA; [1–13C]palmitate) and ketone body (KB; [3,4–13C2]acetoacetate) kinetics, before and after intraperitoneal injection of saline or TNF-alpha, in postabsorptive rats or rats starved for 24 h. In both groups of rats, TNF-alpha injection did not modify insulinemia and induced a moderate increase of FFA concentrations and appearance rates (P < 0.05). Despite increased FFA availability, ketogenesis was impaired after TNF-alpha injection, as shown by lower KB concentrations and appearance rates; this effect was more important in postabsorptive than in starved rats. The percentage of FFA flux used for ketogenesis was decreased by TNF-alpha in the postabsorptive group (P < 0.05) and starved (P < 0.05) rats. In both groups, maximal liver acetyl-coenzyme A carboxylase activity and estimated phosphorylation state were not modified by TNF-alpha injection, but hepatic concentrations of citrate were increased (P < 0.05). This increased citrate level could be related to a mobilization of glucose stored as glycogen since liver glycogen was decreased by TNF-alpha injection (P < 0.05). In conclusion, TNF-alpha injection in rats decreased hepatic ketogenesis. This action could be related to an increased mobilization and utilization of carbohydrate stores.


Blood ◽  
1991 ◽  
Vol 78 (3) ◽  
pp. 571-574 ◽  
Author(s):  
RB Lal ◽  
DL Rudolph

Abstract The human T-cell lymphotropic viruses (HTLV) type I and type II are capable of inducing a variety of cellular genes, including many of the cytokines that regulate cell proliferation. To determine if the spontaneous proliferation of peripheral blood mononuclear cells from patients infected with HTLV-I and HTLV-II was related to coordinate expression of cytokines, we analyzed the levels of interleukin-1 beta (IL-1 beta), IL-2, IL-3, IL-4, IL-6, tumor necrosis factor-alpha (TNF- alpha) and interferon-tau (IFN-tau) in culture supernatants derived from spontaneously proliferating cells. Significantly elevated levels of IL-6 and TNF-alpha were present in culture supernatants from HTLV- I/II-infected individuals when compared with normal controls (P less than .01). Kinetic experiments showed that both IL-6 and TNF-alpha were elevated by day 5. None of the other cytokines (IL-1 beta, IL-2, IL-3, IL-4, and IFN-tau) were detectable in any of the culture. These data suggest that release of IL-6 and TNF-alpha may regulate lymphocyte proliferation in HTLV-I/II-infected individuals.


Blood ◽  
1992 ◽  
Vol 79 (12) ◽  
pp. 3362-3368 ◽  
Author(s):  
P Herve ◽  
M Flesch ◽  
P Tiberghien ◽  
J Wijdenes ◽  
E Racadot ◽  
...  

Abstract In a multicenter pilot study, 19 patients with severe acute graft- versus-host disease (aGVHD) refractory to conventional therapy and serotherapy with a monoclonal anti-interleukin-2 receptor antibody were treated by in vivo infusion of a monoclonal anti-tumor necrosis factor alpha (TNF alpha) antibody (B-C7). Ten patients were grafted from a genotypically identical sibling, five from an HLA-mismatched family member, and four from an HLA-matched unrelated donor. Before B-C7 treatment, 15 patients had grade IV and four had grade III GVHD. In all cases, patients received cyclosporine/methotrexate as aGVHD prophylaxis. Patients were administered increasing doses of antibody (from 0.1 to 0.4 mg/kg). The antibody was infused in bolus daily for 4 days and then every other day twice (6 doses). No side effects were observed during treatment regardless of the dose level used. Changes in peripheral blood cell counts occurred in 8 of the 19 patients and appeared to be unrelated to B-C7. No truly complete response was observed; eight patients achieved a very good partial response (42.6%) and six a partial response (31.5%). The treatment was ineffective in five patients (26.4%). When present, the response occurred early (less than 3 days). In the 14 responding patients, gut lesions responded best (100%), followed by skin (85%) and liver (35.7%) lesions. In 9 of 11 evaluable patients (81%), GVHD recurred when treatment was discontinued in a median delay of 3 days (range, 2 to 120 days). All except one died from aGVHD. Two patients did not experience GVHD recurrence and are still alive 13 and 18 months post-bone marrow transplantation. This pilot study shows that a monoclonal anti-TNF alpha antibody may be of benefit to some patients with severe refractory aGVHD, but is ineffective to prevent GVHD recurrence in the majority of cases.


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