Epidermal Growth Factor Improves Intestinal Integrity and Survival in Murine Sepsis Following Chronic Alcohol Ingestion

Abstract

Epidermal growth factor (EGF) is a cytoprotective protein that improves survival in preclinical models of sepsis through its beneficial effects on intestinal integrity. Alcohol use disorder worsens intestinal integrity and is associated with increased morbidity and mortality in critical illness. We sought to determine whether chronic alcohol ingestion alters the host response to systemic administration of EGF in sepsis. Six week old FVB/N mice were randomized to receive 20% alcohol or water for 12 weeks. All mice then underwent cecal ligation and puncture (CLP) to induce polymicrobial sepsis. Mice were then randomized to receive either intraperitoneal injection of EGF (150 μg/kg/day) or normal saline. Water-fed mice given EGF mice had decreased seven-day mortality compared to water-fed mice (18% vs. 55%). Alcohol-fed mice given EGF also had decreased seven day mortality compared to alcohol-fed mice (48% vs. 79%). Notably, while systemic EGF improved absolute survival to a similar degree in both water-fed and alcohol-fed mice, mortality was significantly higher in alcohol+EGF mice compared to water+EGF mice. Compared to water-fed septic mice, alcohol-fed septic mice had worsened intestinal integrity with intestinal hyperpermeability, increased intestinal epithelial apoptosis, decreased proliferation and shorter villus length. Systemic administration of EGF to septic alcohol-fed mice decreased intestinal permeability compared to septic alcohol-fed mice given vehicle, with increased levels of the tight junction mediators claudin-5 and JAM-A. Systemic administration of EGF to septic alcohol-fed mice also decreased intestinal apoptosis with an improvement in the Bax/Bcl-2 ratio. EGF also improved both crypt proliferation and villus length in septic alcohol-fed mice. EGF administration resulted in lower levels of both pro- and anti-inflammatory cytokines MCP-1, TNF and IL-10 in alcohol-fed mice. EGF is therefore effective at improving both intestinal integrity and mortality following sepsis in mice with chronic alcohol ingestion. However, the efficacy of EGF in sepsis is blunted in the setting of chronic alcohol ingestion, as intestinal integrity and mortality in alcohol-fed mice given EGF improves animals to levels seen in water-fed mice given vehicle but does not approach levels seen in water-fed mice given EGF.

The intestinal microenvironment in sepsis

“…EGF also improves intestinal permeability via a decrease in the pore forming tight junction mediator claudin 2. Notably, the effects of EGF are complicated as systemic EGF improves permeability in septic mice with pre-existing alcohol use disorder via increased levels of the tight junction mediators claudin-5 and junctional adhesion molecule A (74). …”

New insights into the gut as the driver of critical illness and organ failure

“…Notably, when alcohol-fed septic animals are given Epidermal Growth Factor, it improves both intestinal integrity and survival to levels seen in water-fed septic animals. However, its efficacy in sepsis is blunted in the setting of chronic alcohol ingestion, since gut integrity and mortality in alcohol-fed septic mice given Epidermal Growth Factor does not approach that in water-fed septic mice given the same agent (20). …”

Sepsis reveals compartment‐specific responses in intestinal proliferation and apoptosis in transgenic mice whose enterocytes re‐enter the cell cycle

“…Simultaneously, gut barrier function is worsened by sepsis, with intestinal hyperpermeability associated with changes in multiple intestinal tight junction proteins (14,15). These changes in gut epithelial integrity appear to be clinically important because when gut integrity can be maintained by decreasing apoptosis, increasing proliferation, or normalizing permeability, survival is improved in animal models of sepsis (16)(17)(18)(19).…”