Biomedical subjects

José L Pascual

Publications and source records attributed to José L Pascual.

4 recordsLinked to original sources

PubMed2003

Science review: Cell membrane expression (connectivity) regulates neutrophil delivery, function and clearance.

As the principal cellular component of the inflammatory host defense and contributor to host injury after severe physiologic insult, the neutrophil is inherently coupled to patient outcome in both health and disease. Extensive research has focused on the mechanisms that regulate neutrophil delivery, function, and clearance from the inflammatory microenvironment. The neutrophil cell membrane mediates the interaction of the neutrophil with the extracellular environment; it expresses a complex array of adhesion molecules and receptors for various ligands, including mediators, cytokines, immunoglobulins, and membrane molecules on other cells. This article presents a review and analysis of the evidence that the neutrophil membrane plays a central role in regulating neutrophil delivery (production, rolling, adhesion, diapedesis, and chemotaxis), function (priming and activation, microbicidal activity, and neutrophil-mediated host injury), and clearance (apoptosis and necrosis). In addition, we review how change in neutrophil membrane expression is synonymous with change in neutrophil function in vivo. Employing a complementary analysis of the neutrophil as a complex system, neutrophil membrane expression may be regarded as a measure of neutrophil connectivity, with altered patterns of connectivity representing functionally distinct neutrophil states. Thus, not only does the neutrophil membrane mediate the processes that characterize the neutrophil lifecycle, but characterization of neutrophil membrane expression represents a technology with which to evaluate neutrophil function.

Antigens, CD↗

PubMed2003

Hypertonic saline resuscitation attenuates neutrophil lung sequestration and transmigration by diminishing leukocyte-endothelial interactions in a two-hit model of hemorrhagic shock and infection.

BACKGROUND: Hypertonic saline (HTS) attenuates polymorphonuclear neutrophil (PMN)-mediated tissue injury after hemorrhagic shock. We hypothesized that HTS resuscitation reduces early in vivo endothelial cell (EC)-PMN interactions and late lung PMN sequestration in a two-hit model of hemorrhagic shock followed by mimicked infection. METHODS: Thirty-two mice were hemorrhaged (40 mm Hg) for 60 minutes and then given intratracheal lipopolysaccharide (10 microg) 1 hour after resuscitation with shed blood and either HTS (4 mL/kg 7.5% NaCl) or Ringer's lactate (RL) (twice shed blood volume). Eleven controls were not manipulated. Cremaster intravital microscopy quantified 5-hour EC-PMN adherence, myeloperoxidase assay assessed lung PMN content (2 1/2 and 24 hours), and lung histology determined 24-hour PMN transmigration. RESULTS: Compared with RL, HTS animals displayed 55% less 5-hour EC-PMN adherence (p = 0.01), 61% lower 24-hour lung myeloperoxidase ( p= 0.007), and 57% lower mean 24-hour lung histologic score ( p= 0.027). CONCLUSION: Compared with RL, HTS resuscitation attenuates early EC-PMN adhesion and late lung PMN accumulation in hemorrhagic shock followed by inflammation. HTS resuscitation may attenuate PMN-mediated organ damage.

Animals↗

PubMed2003

Hypertonic saline and the microcirculation.

The systemic inflammation that occurs in shock states is believed to promote overexuberant microcirculatory activation, the release of toxic proteases and oxygen radicals causing microvascular damage, and subsequent tissue and organ injury. Although shock-associated microvascular failure is often unresolved after standard resuscitation, hypertonic saline (HTS) appears to reduce microvascular collapse, restoring vital nutritional blood flow. In addition, hypertonic fluids tend to blunt the up-regulation of leukocyte and endothelial adhesion molecules that occurs with isotonic resuscitation of shock. Recently, direct evaluation by intravital microscopy has shown that HTS resuscitation dampens the interactions between leukocytes, platelets, and endothelium found with Ringer's lactate resuscitation. Furthermore, fewer cellular interactions have been correlated with attenuation in microvascular wall permeability after resuscitation with HTS. Better characterization of microcirculatory effects by hypertonic saline may provide mechanisms for improved morbidity and mortality associated with hypertonic resuscitation.

Fluid Therapy↗

PubMed2002

Hypertonic saline resuscitation of hemorrhagic shock diminishes neutrophil rolling and adherence to endothelium and reduces in vivo vascular leakage.

OBJECTIVE: To evaluate the in vivo effects of hypertonic saline (HTS) resuscitation on the interactions of endothelial cells (ECs) and polymorphonuclear neutrophils (PMNs) and vascular permeability after hemorrhagic shock. SUMMARY BACKGROUND DATA: The PMN has been implicated in the pathogenesis of EC damage and organ injury following hemorrhagic shock. Compared to Ringer's lactate (RL), HTS resuscitation diminishes PMN and EC adhesion molecule expression and organ sequestration of PMNs. METHODS: In a murine model of hemorrhagic shock (50 mmHg for 45 minutes followed by resuscitation) using intravital microscopy on cremaster muscle, the authors studied PMN-EC interactions and vascular leakage (epifluorescence after 50 mg/kg fluorescent albumin) in three resuscitation groups: HTS (shed blood + 4 cc/kg 7.5% HTS, n = 12), RL (shed blood + RL [2x shed blood volume], n = 12), and sham (no hemorrhage or resuscitation, n = 9). EC ICAM-1 expression was evaluated by immunohistochemistry. Data, presented as mean +/- SEM, were evaluated by analysis of variance with Bonferroni correction. RESULTS: There were no differences between groups in flow mechanics. Compared to RL, HTS animals (t = 90 minutes) displayed diminished PMN rolling and PMN adhesion to EC at time intervals beyond t = 0. There were no differences between the sham and HTS groups. Vascular leakage was 45% lower in HTS than in RL-resuscitated animals. Cremaster EC ICAM-1 expression was similar in the two groups. CONCLUSIONS: Using HTS instead of RL to resuscitate hemorrhagic shock diminishes vascular permeability in vivo by altering PMN-EC interactions. HTS could serve as a novel means of immunomodulation in hemorrhagic shock victims, potentially reducing PMN-mediated tissue injury.

Animals↗