Biomedical subjects

Otelo Rigato

Publications and source records attributed to Otelo Rigato.

4 recordsLinked to original sources

PubMed2006

Bacterial recognition and induced cell activation in sepsis.

The pathogenesis of sepsis involves complex interaction between the host and the infecting microorganism. Recognition and processing of microorganism antigens are essential functions of the cells of innate immune systems, and will ultimately, through the antigen presentation to the cells of adaptive immunity and the synthesis and secretions of mediators, such as cytokines, drive a coordinated immune response. Neutrophils and monocytes will therefore function as sensing and effectors cells. Fundamental in this process is the ability to discriminate self from non-self molecules. Of major interest in sepsis is that the protective and damaging host responses are part of the same process, that is, the inflammatory response that controls the infection process also underscores many of the pathophysiological events of sepsis. Moreover, this is a dynamic process according to the continuum of sepsis and its complications; up and down regulation of cellular activities may be differently regulated in different tissues, different cells and even in different functions of the same cell. This review will focus on microorganism recognition and signalization in sepsis, with emphasis on the neutrophils and monocytes adaptation during the ongoing disease.

Animals↗

PubMed2006

Pathogenesis-oriented targets for adjunctive therapy.

The outcome of patients with sepsis arises from multiple factors affecting both the host and the invading microorganisms. Even within the setting of adequate antimicrobial use, patients still die of sepsis. Thus, strategies focusing on further therapy targets are an important area of interest for basic and clinical research. Although such adjunctive sepsis therapy has failed to achieve consistent better survival rates so far, the progress in understanding of the pathophysiology of sepsis seen in recent years is so profound, that the possibility that a new and effective treatment may arise should be warmly considered. Indeed, it may be considered that efficacious interventions, such as early and vigorous fluid replacement, strict blood glucose control, low-dose corticosteroid reposition, protective mechanical ventilation and activated-protein C are pathogenic-oriented targets of therapy. In this paper we aim to review some aspects of the pathogenesis of sepsis, focusing on possible targets for adjunctive therapy. Published clinical trials and experimental data supporting such trials are commented on.

Animals↗

PubMed2003

Impaired production of interferon-gamma and tumor necrosis factor-alpha but not of interleukin 10 in whole blood of patients with sepsis.

It has been demonstrated that lipopolysaccharide (LPS)-induced cytokine response in patients with sepsis differ from the normal host, yet this has not been controlled for the presence of underlying disease. We studied the ability of LPS and killed gram-negative bacteria (GNB) to induce tumor necrosis factor (TNF)-alpha and interleukin (IL) 10, and of phytohemagglutinin (PHA) to induce interferon (IFN)-gamma, in whole blood from patients with sepsis (SP, n = 20), patients with matched underlying disease and without sepsis (control patients, n = 20), and healthy volunteers (HV, n = 20). LPS-induced TNF-alpha production was lower in SP (median = 638 pg/mL) compared with control patients (4060 pg/mL; P= 0.003), and control patients production was lower compared with HV (5329 pg/mL; P < 0.001). Pseudomonas aeruginosa-induced TNF-alpha production was lower in SP (1443 pg/mL) than in control patients (7319 pg/mL; P < 0.05), and was not different between control patients and HV (6612 pg/mL; P = 0.6). IFNy production was lower in SP (948 pg/mL) compared with control patients (5516 pg/mL; P < 0.001), and the control patients production was lower compared with HV (11,282 pg/mL; P < 0.001). IL-10 production was not different among the three groups. Down-regulation of TNF-alpha production in patients with sepsis, although not restricted to them, was more pronounced with LPS than with GNB. Although the presence of underlying disease may be involved in the regulatory mechanisms of host response, the use of controls with matched underlying diseases provides strong evidence for the septic condition in the down-regulation of inflammatory response in patients with sepsis.

Adult↗

PubMed2002

Lipopolysaccharide-cell interaction and induced cellular activation in whole blood of septic patients.

We used biotinylated LPS (LPSb) and flow cytometry to study LPS-monocyte interaction and LPS-induced cellular activation in whole blood from septic patients (SP). Expression of surface activation markers was evaluated on monocytes (HLA-DR) and T lymphocytes (CD69 and CD95), and intracellular TNF-alpha on monocytes. Saturating curve and kinetics of LPSb detection on monocytes were similar in SP and healthy volunteers (HV). LPSb bound to monocytes was detected after 5 min of incubation in both groups, with a more pronounced decay in SP. Monocytes from SP had a lower expression of HLA-DR as compared to HV, both constitutive and upon LPS stimulation. The proportion of monocytes producing TNF-alpha after LPS stimulus was higher in HV than SP (mean +/- SD = 25.2 +/- 14.2% and 2.2 +/- 2.6%, respectively, P < 0.001). LPS-induced CD69 on T CD8+ and CD8- lymphocytes was similar for patients and controls. Expression of CD95 on T lymphocytes was higher in SP as compared to HV on T CD8+ cells (GMFI, mean +/- SD = 22.3 +/- 14.6 and 8.6 +/- 5.0, respectively, P = 0.01) and CD8- cells (GMFI, mean +/- SD = 28.3 +/- 7.7 and 14 +/- 4.3 respectively, P < 0.001). Thus, monocytes and lymphocytes seem to respond differently to LPS in septic patients. Monocyte hyporesponsiveness appears not to be related to a decreased binding capacity of LPS, but rather to an impaired signal transduction.

Adolescent↗