ABSTRACT
Sepsis causes long-term disability, such as immune dysfunction, neuropsychological disorders, persistent inflammation, catabolism, and immunosuppression, leading to a high risk of death in survivors, although the contributing factors of mortality are unknown. The purpose of this experimental study in rats was to examine renal (rSNA) and splanchnic (sSNA) sympathetic nerve activity, as well as baroreflex sensitivity, in acute and chronic post-sepsis periods. The rats were divided into two groups: control group with naïve Wistar rats and sepsis group with 2-mL intravenous inoculation of Escherichia coli at 108 CFU/mL. Basal mean arterial pressure, heart rate, rSNA, sSNA, and baroreflex sensitivity were evaluated in all groups at the acute (6 h) and chronic periods (1 and 3 months). Basal rSNA and sSNA were significantly reduced in the surviving rats, as was their baroreflex sensitivity, for both pressor and hypotensive responses, and this effect lasted for up to 3 months. A single episode of sepsis in rats was enough to induce long-term alterations in renal and splanchnic sympathetic vasomotor nerve activity, representing a possible systemic event that needs to be elucidated. These findings showed that post-sepsis impairment of sympathetic vasomotor response may be one of the critical components in the inability of sepsis survivors to respond effectively to new etiological illness factors, thereby increasing their risk of post-sepsis morbidity.
ABSTRACT
Although enteropathogenic Escherichia coli (EPEC) are well-recognized diarrheal agents, their ability to translocate and cause extraintestinal alterations is not known. We investigated whether a typical EPEC (tEPEC) and an atypical EPEC (aEPEC) strain translocate and cause microcirculation injury under conditions of intestinal bacterial overgrowth. Bacterial translocation (BT) was induced in female Wistar-EPM rats (200-250 g) by oroduodenal catheterization and inoculation of 10 mL 10(10) colony forming unit (CFU)/mL, with the bacteria being confined between the duodenum and ileum with ligatures. After 2 h, mesenteric lymph nodes (MLN), liver and spleen were cultured for translocated bacteria and BT-related microcirculation changes were monitored in mesenteric and abdominal organs by intravital microscopy and laser Doppler flow, respectively. tEPEC (N = 11) and aEPEC (N = 11) were recovered from MLN (100 percent), spleen (36.4 and 45.5 percent), and liver (45.5 and 72.7 percent) of the animals, respectively. Recovery of the positive control E. coli R-6 (N = 6) was 100 percent for all compartments. Bacteria were not recovered from extraintestinal sites of controls inoculated with non-pathogenic E. coli strains HB101 (N = 6) and HS (N = 10), or saline. Mesenteric microcirculation injuries were detected with both EPEC strains, but only aEPEC was similar to E. coli R-6 with regard to systemic tissue hypoperfusion. In conclusion, overgrowth of certain aEPEC strains may lead to BT and impairment of the microcirculation in systemic organs.