Intravenous phage display identifies peptide sequences that target the burn-injured intestine.

The injured intestine is responsible for significant morbidity and mortality after severe trauma and burn; however, targeting the intestine with therapeutics aimed at decreasing injury has proven difficult. We hypothesized that we could use intravenous phage display technology to identify peptide sequences that target the injured intestinal mucosa in a murine model, and then confirm the cross-reactivity of this peptide sequence with ex vivo human gut. Four hours following 30% TBSA burn we performed an in vivo, intravenous systemic administration of phage library containing 10(12) phage in balb/c mice to biopan for gut-targeting peptides.

Targeting α-7 nicotinic acetylcholine receptor in the enteric nervous system: a cholinergic agonist prevents gut barrier failure after severe burn injury.

We have previously shown that vagal nerve stimulation prevents intestinal barrier loss in a model of severe burn injury in which injury was associated with decreased expression and altered localization of intestinal tight junction proteins. α-7 Nicotinic acetylcholine receptor (α-7 nAchR) has been shown to be necessary for the vagus nerve to modulate the systemic inflammatory response, but the role of α-7 nAchR in mediating gut protection remained unknown. We hypothesized that α-7 nAchR would be present in the gastrointestinal tract and that treatment with a pharmacological agonist of α-7 nAchR would protect against burn-induced gut barrier injury.

Efferent vagal nerve stimulation attenuates acute lung injury following burn: The importance of the gut-lung axis.

Background: The purpose of this study was to assess acute lung injury when protection to the gut mucosal barrier offered by vagus nerve stimulation is eliminated by an abdominal vagotomy.

Methods: Male balb/c mice were subjected to 30% total body surface area steam burn with and without electrical stimulation to the right cervical vagus nerve. A cohort of animals were subjected to abdominal vagotomy.

Vagal nerve stimulation protects against burn-induced intestinal injury through activation of enteric glia cells.

The enteric nervous system may have an important role in modulating gastrointestinal barrier response to disease through activation of enteric glia cells. In vitro studies have shown that enteric glia activation improves intestinal epithelial barrier function by altering the expression of tight junction proteins. We hypothesized that severe injury would increase expression of glial fibrillary acidic protein (GFAP), a marker of enteric glial activation.

A novel fluid resuscitation strategy modulates pulmonary transcription factor activation in a murine model of hemorrhagic shock.

Introduction: Combining the hemodynamic and immune benefits of hypertonic saline with the anti-inflammatory effects of the phosphodiesterase inhibitor pentoxifylline (HSPTX) as a hemorrhagic shock resuscitation strategy reduces lung injury when compared with the effects of Ringer's lactate (RL). We hypothesized that HSPTX exerts its anti-inflammatory effects by interfering with nuclear factor kappa B/cAMP response element-binding protein (NF-kappaB-CREB) competition for the coactivator CREB-binding protein (CBP) in lung tissue, thus affecting pro-inflammatory mediator production.

Methods: Male Sprague-Dawley rats underwent 60 minutes of hemorrhagic shock to reach a mean arterial blood pressure of 35 mmHg followed by resuscitation with either RL or HSPTX (7.

Efferent vagal nerve stimulation attenuates gut barrier injury after burn: modulation of intestinal occludin expression.

Introduction: Severe injury can cause intestinal permeability through decreased expression of tight junction proteins, resulting in systemic inflammation. Activation of the parasympathetic nervous system after shock through vagal nerve stimulation is known to have potent anti-inflammatory effects; however, its effects on modulating intestinal barrier function are not fully understood. We postulated that vagal nerve stimulation improves intestinal barrier integrity after severe burn through an efferent signaling pathway, and is associated with improved expression and localization of the intestinal tight junction protein occludin.

Toll-like receptor-4 mediates intestinal barrier breakdown after thermal injury.

Objective: Toll-like receptor 4 (TLR-4) activation after sterile injury leads to organ dysfunction at distant sites. We have shown previously that intestinal barrier breakdown and alteration of tight junction proteins follows thermal injury; however, the role of TLR-4 in this process remains unclear. We hypothesized that increased intestinal permeability and barrier breakdown after burns is a TLR-4 dependent process; hence, knocking down the TLR-4 gene would have a protective effect on burn-induced intestinal dysfunction.

Quantitative assessment of intestinal injury using a novel in vivo, near-infrared imaging technique.

Intestinal injury owing to inflammation, severe trauma, and burn is a leading cause of morbidity and mortality. Currently, animal models employed to study the intestinal response to injury and inflammation depend on outdated methods of analysis. Given that these classic intestinal assays are lethal to the experimental animal, there is no ability to study the gut response to injury in the same animal over time.

Burns, inflammation, and intestinal injury: protective effects of an anti-inflammatory resuscitation strategy.

Background: Intestinal barrier breakdown after severe burn can lead to intestinal inflammation, which may act as the source of the systemic inflammatory response. In vitro intestinal cell studies have shown that mitogen-activated protein kinase (MAPK) signaling is an important modulator of intestinal inflammation. We have previously observed that pentoxifylline (PTX) attenuates burn-induced intestinal permeability and tight junction breakdown.

Pentoxifylline modulates p47phox activation and downregulates neutrophil oxidative burst through PKA-dependent and -independent mechanisms.

Background And Aim: Pentoxifylline (PTX) has been proven to be an inhibitor of fMLP-induced neutrophil (PMN) oxidative burst and is thought to function by increasing cAMP and Protein kinase A (PKA). We hypothesized that PTX diminishes production of the neutrophil respiratory burst by both PKA-dependent and independent mechanisms.

Material And Methods: Human neutrophils were isolated and stimulated with fMLP (1microM) alone or in combination with PTX (2mM).

Targeting the gut barrier: identification of a homing peptide sequence for delivery into the injured intestinal epithelial cell.

Background: Severe injury results in intestinal barrier dysfunction that may be responsible for significant morbidity and mortality. We postulated that mining a peptide library that was displayed on phage would identify peptide sequences that bind and internalize into the gut epithelium following injury.

Methods: We utilized a severe full thickness burn in mice as a model of severe injury.

Pentoxifylline modulates intestinal tight junction signaling after burn injury: effects on myosin light chain kinase.

Background: Burn injury can result in loss of intestinal barrier function, leading to systemic inflammatory response syndrome and multiorgan failure. Myosin light chain kinase (MLCK), a tight junction protein involved in the regulation of barrier function, increases intestinal epithelial permeability when activated. Prior studies have shown that tumor necrosis factor (TNF)-alpha activates MLCK, in part through a nuclear factor (NF)-kappa B-dependent pathway.

Phosphodiesterase inhibition attenuates alterations to the tight junction proteins occludin and ZO-1 in immunostimulated Caco-2 intestinal monolayers.

Aims: Under normal conditions, the intestinal mucosa acts as a local barrier to prevent the influx of luminal contents. The intestinal epithelial tight junction is comprised of several membrane associated proteins, including zonula occludens-1 (ZO-1) and occludin. Disruption of this barrier can lead to the production of pro-inflammatory mediators and ultimately multiple organ failure.

Burn-induced gut barrier injury is attenuated by phosphodiesterase inhibition: effects on tight junction structural proteins.

Loss of intestinal barrier function after burn injury allows movement of intraluminal contents across the mucosa, which can lead to the development of distant organ injury and multiple organ failure. Tight junction function is highly regulated by membrane-associated proteins including occludin and zonula occludens protein 1 (ZO-1), which can be modulated by systemic inflammation. We hypothesized that (1) burn injury leads to gut barrier injury, and (2) phosphodiesterase inhibition will attenuate these burn-induced changes.

Pentoxifylline attenuates pulmonary inflammation and neutrophil activation in experimental acute pancreatitis.

Objectives: Acute pancreatitis (AP) is associated with a systemic inflammatory response. Pentoxifylline (PTX) has been shown to attenuate neutrophil activation and end-organ injury in shock states such as hemorrhage and sepsis. We hypothesized that PTX would down-regulate AP-induced lung injury.

Pentoxifylline attenuates lung injury and modulates transcription factor activity in hemorrhagic shock.

Background: Evidence exists that resuscitation with Ringer's lactate (RL) contributes to postshock inflammation and lung injury. We hypothesized that the anti-inflammatory agent pentoxifylline (PTX) attenuates postresuscitative lung injury through modulation of transcription factors after hemorrhagic shock.

Methods: Male Sprague Dawley rats underwent a 1 h period of hypotension and resuscitation with RL (32 mL/kg) or RL + PTX (25 mg/kg).

The effects of a novel resuscitation strategy combining pentoxifylline and hypertonic saline on neutrophil MAPK signaling.

Background: The combination of hypertonic saline (HS) and pentoxifylline (PTX) has been shown to synergistically downregulate neutrophil oxidative burst in vitro. We investigated the effects of HS/PTX on human neutrophil mitogen-activated protein kinase (MAPK) signaling and the role of Protein kinase A (PKA) in this process.

Methods: Isolated neutrophils were treated with PTX (2 mmol/L), HS10 (10 mmol/L above isotonicity), and HS40 (40 mmol/L above isotonicity) alone or in combination for determination of intracellular cyclic adenosine monophosphate (cAMP) concentrations.