Elizabeth J. Kovacs

Fibrogenic cytokines and connective tissue production.

The pathogenesis of fibrotic disorders is similar regardless of the tissues involved. Inflammatory leukocytes infiltrate the site triggered by chemotactic and activating mediators. This is followed by the elaboration of cytokines that directly and indirectly induce the proliferation of fibroblasts and endothelial cells and the deposition of extracellular matrix (ECM). In the absence of inhibitory signals, the continued production of these mediators sustains the connective tissue accumulation, which results in permanent alteration in tissue structure and function.— Kovacs, E. J., DiPietro, L. A. Fibrogenic cytokines and connective tissue production. FASEB J. 8: 854‐861; 1994.

Effects of acute ethanol exposure on cellular immune responses in a murine model of thermal injury.

To test the effects of acute ethanol exposure on immune function after thermal injury, mice with blood alcohol levels of 100 mg/dL were given a 15% total body surface area dorsal scald or sham injury. Bacterial challenge resulted in 100 and 40% mortality in burn + ethanol‐ and burn + vehicle‐treated mice, respectively. Delayed‐type hypersensitivity responses were also significantly suppressed in burn + ethanol‐treated mice. At 1 and 4 days post‐burn, concanavalin A (ConA) ‐induced total splenocyte proliferation in burn + ethanol‐treated groups was significantly decreased (P < 0.01) compared with burn + vehicle‐ or sham‐treated animals. This decrease was not observed in total splenocytes cultured with anti‐CD3ε or among adherence‐depleted splenocytes given ConA or anti‐CD3ε. FACS analyses revealed no changes in splenocyte sub‐type ratios in burn + ethanol mice. The data herein demonstrate that acute ethanol exposure before thermal injury results in enhanced susceptibility to bacterial infection and markedly suppressed cellular immunity, which appears to be macrophage dependent. J. Leukoc. Biol. 62: 733–740; 1997.

Acute Ethanol Exposure Prior To Thermal Injury Results In Decreased T-cell Responses Mediated In Part By Increased Production Of Il-6

Previous studies by our laboratory have demonstrated that acute ethanol exposure prior to thermal injury results in suppression of cellular immune responses when compared with thermal injury alone. Ethanol exposure and burn injury are independently known to result in elevated IL-6, a cytokine with potent immunosuppressive properties. Therefore, we examined the role of IL-6 in the immune dysfunction in mice following a 15% body surface area scald (or sham) injury combined with acute ethanol (or vehicle) treatment. At 24 h post-injury, we observed slightly suppressed splenocyte proliferative responses and elevated circulating IL-6 (149 ± 15 pg/mL) in mice receiving burn alone compared with those receiving sham injury (31 ± 7 pg/mL). In contrast, burn + ethanol treated mice showed a profound suppression of splenocyte proliferation (20% of control) and significantly elevated circulating IL-6 levels (738 ± 218 pg/mL). The suppressed splenocyte proliferative response was found to be macrophage dependent. Furthermore, IL-6 production was significantly elevated (p < .05) in splenic macrophage cultures from burn + ethanol mice (159 ± 6 pg/mL) when compared with burn alone (109 ± 10 pg/mL). Treatment of the splenocyte cultures from burn + ethanol mice with an anti-IL6 monoclonal antibody resulted in partial restoration of splenocyte proliferation. Taken together, these data strongly suggest that the immune dysfunction observed in ethanol-exposed, thermally injured mice is mediated in part by elevated levels of IL-6.

Neutrophil chemokine production in the skin following scald injury

The present study was conducted to determine whether local production of neutrophil chemoattractant cytokines preceded the influx of neutrophils following dermal scald injury. To accomplish this, dermal tissue was examined for inflammatory infiltrate and the level of KC, a murine homolog of human interleukin-8, at various time points after scald injury. The studies reveal that there was a largely neutrophilic infiltrate at 1 day post-injury which persisted for 4 days. Dermal KC levels increased significantly at 4 h, returned to baseline at 8 h and were elevated again from 1 to 3 days post-burn (P < 0.01). At 3 days post-burn, KC was elevated 15-fold above the level in sham treated mice (P < 0.01). These observations demonstrate that the influx of neutrophils into the skin follows the expression of KC in the skin. This suggests that it should be possible to alter neutrophil accumulation at the wound site by manipulating the local chemokine signal.

Gender difference in cell-mediated immunity after thermal injury is mediated, in part, by elevated levels of interleukin-6.

The gender difference in normal immune function has been well documented, however, there is only limited information regarding whether such a difference occurs after injury. To investigate this, we examined cell‐mediated immune responses in male and female mice given a 15% total body surface area dorsal scald or sham injury. Both delayed‐type hypersensitivity (DTH) and splenocyte proliferative responses were significantly suppressed in males at 1 day and in females at 7 and 10 days post burn (P < 0.01). The decreased splenocyte proliferation was found to be macrophagedependent and suppression of both immune parameters corresponded with elevated interleukin‐6 (IL‐6) levels. Furthermore, post‐burn treatment with an anti‐IL‐6 antibody partially restored the DTH response in males at 1 day and females at 10 days post injury and completely restored splenocyte proliferation. These data demonstrate a possible mechanism for the gender difference in cell‐mediated immune responses after thermal injury. J. Leukoc. Biol. 67: 319–326; 2000.

Estrogen restores cellular immunity in injured male mice via suppression of interleukin-6 production

This study examined whether estrogen treatment can improve immunity in male mice after combined ethanol and burn injuries. 17β‐Estradiol [estrogen, given subcutaneously (s.c.)] or oil (control) was administered at 30 min and 24 h postinjury. At 48 h postinjury, ethanol/burn‐injured mice demonstrated significant suppression of cellular immunity. Estrogen treatment restored the delayed‐type hypersensitivity (P<0.01) and splenocyte‐proliferative (P<0.05) responses, reduced macrophage interleukin‐6 (IL‐6) (P<0.05), and increased survival after bacterial challenge (P<0.01). In vitro neutralization of IL‐6, combined with macrophage supernatant experiments, confirmed that the beneficial effects of estrogen treatment were mediated through modulation of macrophage IL‐6 production. Moreover, estrogen treatment resulted in a decrease in splenic nuclear factor‐κB (NF‐κB) activation in injured mice. There were no changes in cellular NF‐κB or IκBα protein expression or IκBα phosphorylation at serine 32. Taken together, these studies suggest that estrogen treatment of injured male mice improves cellular immunity through direct modulation of NF‐κB activation.

Adverse Clinical Outcomes Associated With Elevated Blood Alcohol Levels at the Time of Burn Injury

Elevated blood alcohol content (BAC) on admission is associated with poorer outcomes, larger burns and more inhalation injury. This study’s purpose was to examine the effects of alcohol through a matched case-controlled study, measuring early and extended markers of clinical outcomes. The hypothesis was that patients with an elevated admission BAC would require more resuscitation and have a longer hospital stay. Admissions 16 to 75 years of age with 15 to 75% TBSA and admission BACs were identified. Patients with BAC >30 mg/dl (BAC+, cases) were matched with patients with undetectable BAC (BAC−, controls), according to age, sex, TBSA, inhalation injury and mechanism. Screening identified 258 patients, 146 with admission BACs. Twenty-seven had a BAC ≥ 30 mg/dl. There were 24 matched pairs. At 24 hours, BAC+ group had larger acute physiology and chronic health evaluation II scores (23.33 vs 18.75, P < .05), fluid requirements (5.25 vs 3.82 L (cc/kg/TBSA), P < .05), and base deficit (11.15 vs 7.15, P < .05). The duration of mechanical ventilation (14.85 vs 4.23 days, P < .05), intensive care unit length of stay (22.85 vs 9.38, P < .05), hospital length of stay (28.95 vs 15.68, P < .05), and mean hospital charges (

Glucocorticoids protect against suppression of T cell responses in a murine model of acute ethanol exposure and thermal injury by regulating IL-6

239,507 vs

Effect of Acute Ethanol Exposure on the Dermal Inflammatory Response After Burn Injury

144,598, P < .05) were increased in the BAC+ patients. Despite matched baseline injury characteristics, elevated BAC was associated with poorer short term and extended clinical outcomes, illustrating the impact of alcohol intoxication on physiologic derangement after burn injury.

Effects of Ethanol on Pulmonary Inflammation in Postburn Intratracheal Infection

Previous reports by this laboratory demonstrated that acute alcohol exposure combined with a 15% body surface area dorsal scald injury results in significant reductions in delayed‐type hypersensitivity (DTH) and splenocyte proliferative responses compared to either insult alone. Previous studies by this lab have also shown that these defects are mediated, in part, by increased production of interleukin‐6 (IL‐6). Because both alcohol exposure and thermal injury are known to modulate glucocorticoid (CORT) levels, and CORT regulates IL‐6 gene expression, the relationship between circulating CORT and IL‐6 production in burn + ethanol mice was examined . At 24 and 48 h post‐burn, a positive correlation existed between circulating CORT levels and measurements of cellular immune function. Administration of exogenous CORT to burn + ethanol‐treated mice resulted in significant restoration (to 60% of control) of DTH and splenocyte proliferative responses. This restoration was concomitant with a down‐regulation of circulating and macrophage‐derived IL‐6. The specificity of CORT in modulating these responses was tested by assessing cellular immune function and IL‐6 levels after glucocorticoid receptor blockade with RU486. Taken together, these data strongly suggest that under normal circumstances CORT protects burned mice from severe immune dysfunction, a protection that is not afforded to burn + ethanol‐treated mice. Furthermore, the immune dysfunction observed in burn + ethanol mice may be due to a lack of glucocorticoid attenuation of IL‐6. J. Leukoc. Biol. 64: 724–732; 1998.