Septic shock, which is triggered by microbial products, is mainly characterised by inadequate tissue perfusion, which can lead to multiple organ dysfunction and death. An intense release of vasoconstrictors agents occurs in the early stages of shock, which can lead to ischemic injury. In this scenario, cGMP could play a key role in counterbalancing these agents and preventing tissue damage. Sildenafil, which is a phosphodiesterase-5 inhibitor, increases cGMP in smooth muscle cells and promotes vasodilation. Thus, the purpose of this study was to investigate the effect of treatment with sildenafil in the early stages of sepsis. Male rats were submitted to either cecal ligation and puncture (CLP) or a sham procedure. Eight h after the procedure, the CLP and sham groups were randomly assigned to receive sildenafil (10mg/kg, gavage) or vehicle, and twelve or twenty-four h later the inflammatory, biochemical and haemodynamic parameters were evaluated. Sepsis significantly increased levels of plasma nitrate/nitrite (NOx), aspartate aminotransferase (AST), alanine aminotransferase (ALT), urea, creatinine, creatine kinase and lactate. Additionally, sepsis led to hypotension, hyporesponsiveness to vasoconstrictor, renal blood flow reduction and also increased lung and kidney myeloperoxidase. Sildenafil increased renal blood flow and reduced the plasma levels of creatinine, lactate and creatine kinase, as well as reducing lung myeloperoxidase. Thus, phosphodiesterase inhibition may be a useful therapeutic strategy if administered at the proper time.

lymphocytes. This unique microenvironment present in the intestinal lamina propria (LP) and mesenteric lymph nodes (mLN) induce tolerance to innocuous antigens from the diet, known as Oral Tolerance. Antigens sampled by intestinal epithelium cells are transferred to specialized dendritic cells, residing in the LP, which migrate to the mesenteric lymph nodes where they participate in the induction of regulatory T cells (Treg). Understanding these phenomena may establish the intestinal mucosa as a tool in therapy of inflammatory bowel diseases and immunological disorders.

Sepsis and septic shock are associated with high mortality and are considered one of the major public health concerns. The onset of sepsis is known as a hyper-inflammatory state that contributes to organ failure and mortality. Recent findings suggest a potential role of two non-receptor protein tyrosine kinases, namely Focal adhesion kinase (FAK) and Proline-rich tyrosine kinase 2 (Pyk2), in the inflammation associated with endometriosis, cancer, atherosclerosis and asthma. Here we investigate the role of FAK-Pyk2 in the pathogenesis of sepsis and the potential beneficial effects of the pharmacological modulation of this pathway by administering the potent reversible dual inhibitor of FAK and Pyk2, PF562271 (PF271) in a murine model of cecal ligation and puncture (CLP)-induced sepsis. Five-month-old male C57BL/6 mice underwent CLP or Sham surgery and one hour after the surgical procedure, mice were randomly assigned to receive PF271 (25 mg/kg, s.c.) or vehicle. Twenty-four hours after surgery, organs and plasma were collected for analyses. In another group of mice, survival rate was assessed every 12 h over the subsequent 5 days. Experimental sepsis led to a systemic cytokine storm resulting in the formation of excessive amounts of both pro-inflammatory cytokines (TNF-α, IL-1β, IL-17 and IL-6) and the anti-inflammatory cytokine IL-10. The systemic inflammatory response was accompanied by high plasma levels of ALT, AST (liver injury), creatinine, (renal dysfunction) and lactate, as well as a high, clinical severity score. All parameters were attenuated following PF271 administration. Experimental sepsis induced an overactivation of FAK and Pyk2 in liver and kidney, which was associated to p38 MAPK activation, leading to increased expression/activation of several pro-inflammatory markers, including the NLRP3 inflammasome complex, the adhesion molecules ICAM-1, VCAM-1 and E-selectin and the enzyme NOS-2 and myeloperoxidase. Treatment with PF271 inhibited FAK-Pyk2 activation, thus blunting the inflammatory abnormalities orchestrated by sepsis. Finally, PF271 significantly prolonged the survival of mice subjected to CLP-sepsis. Taken together, our data show for the first time that the FAK-Pyk2 pathway contributes to sepsis-induced inflammation and organ injury/dysfunction and that the pharmacological modulation of this pathway may represents a new strategy for the treatment of sepsis.

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Objective:Periodontitis is associated with endothelial dysfunction, which is clinically characterized by a reduction in endothelium-dependent relaxation. However, we have previously shown that impairment in endothelium-dependent relaxation is transient. Therefore, we evaluated which mediators are involved in endothelium-dependent relaxation recovery.Material and methods:Rats were subjected to ligature-induced experimental periodontitis. Twenty-one days after the procedure, the animals were prepared for blood pressure recording, and the responses to acetylcholine or sodium nitroprusside were obtained before and 30 minutes after injection of a nitric oxide synthase inhibitor (L-NAME), cyclooxygenase inhibitor (Indomethacin, SC-550 and NS- 398), or calcium-dependent potassium channel blockers (apamin plus TRAM- 34). The maxilla and mandible were removed for bone loss analysis. Blood and gingivae were obtained for C-reactive protein (CRP) and myeloperoxidase (MPO) measurement, respectively.Results:Experimental periodontitis induces bone loss and an increase in the gingival MPO and plasmatic CRP. Periodontitis also reduced endothelium-dependent vasodilation, a hallmark of endothelial dysfunction, 14 days after the procedure. However, the response was restored at day 21. We found that endothelium-dependent vasodilation at day 21 in ligature animals was mediated, at least in part, by the activation of endothelial calcium-activated potassium channels.Conclusions:Periodontitis induces impairment in endothelial-dependent relaxation; this impairment recovers, even in the presence of periodontitis. The recovery is mediated by the activation of endothelial calcium-activated potassium channels in ligature animals. Although important for maintenance of vascular homeostasis, this effect could mask the lack of NO, which has other beneficial properties.