Effects of burns on gut motor and mucosa functions

Lung Protection After Severe Thermal Burns With Adenosine, Lidocaine, and Magnesium (ALM) Resuscitation and Importance of Shams in a Rat Model

The management of severe burns remains a complex challenge. Adenosine, lidocaine, and magnesium (ALM) resuscitation therapy has been shown to protect against hemorrhagic shock and traumatic injury. The aim of the present study was to investigate the early protective effects of small-volume ALM fluid resuscitation in a rat model of 30% total body surface area (TBSA) thermal injury. Male Sprague-Dawley rats (320-340 g; n = 25) were randomly assigned to: 1) Sham (surgical instrumentation and saline infusion, without burn, n = 5), 2) Saline resuscitation group (n = 10), or 3) ALM resuscitation group (n = 10). Treatments were initiated 15-min after burn trauma, including 0.7 mL/kg 3% NaCl ± ALM bolus and 0.25-0.5 mL/kg/h 0.9% NaCl ± ALM drip, with animals monitored to 8.25-hr post-burn. Hemodynamics, cardiac function, blood chemistry, hematology, endothelial injury markers and histopathology were assessed. Survival was 100% for Shams and 90% for both ALM and Saline groups. Shams underwent significant physiological, immune and hematological changes over time as a result of surgical traums. ALM significantly reduced malondialdehyde levels in the lungs compared to Saline (P = .023), and showed minimal alveolar destruction and inflammatory cell infiltration (P < .001). ALM also improved cardiac function and oxygen delivery (21%, P = .418 vs Saline), reduced gut injury (P < .001 vs Saline), and increased plasma adiponectin (P < .001 vs baseline). Circulating levels of the acute phase protein alpha 1-acid glycoprotein (AGP) increased 1.6-times (P < .001), which may have impacted ALM's therapeutic efficacy. We conclude that small-volume ALM therapy significantly reduced lung oxidative stress and preserved alveolar integrity following severe burn trauma. Further studies are required to assess higher ALM doses with longer monitoring periods.

Wei-Tong-Xin ameliorated cisplatin-induced mitophagy and apoptosis in gastric antral mucosa by activating the Nrf2/HO-1 pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Wei-Tong-Xin (WTX) originated from the famous ancient Chinese formula "Wan Ying Yuan", recorded in the ancient Chinese medicine book "Zhong Zang Jing" by Hua Tuo. As "Jun" drugs, Dahuang and Muxiang have the effects of clearing heat and expelling fire, reducing food retention, regulating Qi and relieving pain. As "Chen" drug, Qianniuzi has the effect of assisting "Jun" drugs. Zhuyazao and Gancao, as "Zuo-Shi" drugs, can reduce toxicity and modulate the medicinal properties of other herbs.

AIM OF THE STUDY

The present study aimed to investigate the effect and mechanism of WTX on the oxidative stress of gastric antrum mucosa in mice with cisplatin (CIS)-induced dyspepsia.

MATERIALS

AND.

METHODS

A variety of experimental methods, including western blot, qRT-PCR, immunofluorescence and immunohistochemistry were performed in vivo and in vitro.

RESULTS

In vivo, WTX restored the number and function of interstitial cells of Cajal (ICCs), accompanied by the inhibition of lipid peroxidation. Moreover, WTX inhibited the activation of Parkin-dependent mitophagy and apoptosis. In vitro, WTX activated the nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) signaling pathway and inactivated mitophagy in GES-1 cells. To explore the role of Nrf2 in WTX's improvement of CIS-induced cell damage, Nrf2 inhibitor ML385 was used in cell experiments. We found that ML385 counteracted the regulation of WTX on mitophagy and apoptosis. Finally, N-acetylcysteine (NAC), a reactive oxygen species (ROS) scavenger, was applied in our experiments, and the results suggested that WTX suppressed the CIS-induced apoptosis via mitochondrial pathway.

CONCLUSIONS

The above results, for the first time, indicated that WTX inhibited mitophagy and apoptosis of gastric antral mucosal cells induced by CIS through the Nrf2/HO-1 signaling pathway.

Gut Microbial Changes and their Contribution to Post-Burn Pathology

ABSTRACT

Burn injuries are a common form of traumatic injury that leads to significant morbidity and mortality worldwide. Burn injuries are characterized by inflammatory processes and alterations in numerous organ systems and functions. Recently, it has become apparent that the gastrointestinal bacterial microbiome is a key component of regulating the immune response and recovery from burn and can also contribute to significant detrimental sequelae after injury, such as sepsis and multiple organ failure. Microbial dysbiosis has been linked to multiple disease states; however, its role in exacerbating acute traumatic injuries, such as burn, is poorly understood. In this article, we review studies that document changes in the intestinal microbiome after burn injury, assess the implications in post-burn pathogenesis, and the potential for further discovery and research.

Changes in post-oral glucose challenge pancreatic polypeptide hormone levels following metabolic surgery: A comparison of gastric bypass and sleeve gastrectomy

BACKGROUND

Pancreatic polypeptide (PP) hormone is a 36-amino-acid peptide released from the pancreas, the serum levels of which have been shown to rise upon food intake. The underlying mechanism for metabolic surgery in the treatment of patients with type 2 diabetes mellitus (T2DM) remains intriguing. We compared post-oral glucose challenge PP levels between patients undergoing laparoscopic gastric bypass (GB) and sleeve gastrectomy (SG) at 1 year after surgery.

METHODS

This hospital-based, prospective study followed up a total of 12 laparoscopic GB and 12 laparoscopic SG patients and evaluated their glucose homeostasis. One year after metabolic surgery, 75-g oral glucose tolerance tests (OGTTs) were performed in the patients in the GB and SG groups and the blood levels of PP were evaluated.

RESULTS

The laparoscopic GB group had stable serum PP levels within 120 min after OGTT; however, the levels were significantly higher in the laparoscopic SG group at 30 min after OGTT. The patients with complete T2DM remission did not exhibit significantly different PP levels at fasting and post-OGTT than those in patients without remission after GB. Similarly, after SG, patients with T2DM remission did not show significantly different PP levels at fasting and post-OGTT than those in patients without T2DM remission.

CONCLUSIONS

No significant difference was found in plasma PP levels after OGTT in T2DM patients that received either GB or SG, or in T2DM remitters or non-remitters 1 year after metabolic surgery.

Plasma glucagon-like peptide 1 was associated with hospital-acquired infections and long-term mortality in burn patients

BACKGROUND

Although glucagon-like peptide 1 levels have been closely associated with inflammation and mortality in septic patients, the clinical importance of glucagon-like peptide 1 on hospital-acquired infections and long-term mortality after burn injury remains unexplored.

METHODS

Plasma samples from 144 burn patients were collected on admission to determine total glucagon-like peptide 1, interleukin 6, and monocyte chemotactic protein-1 levels. Hospital-acquired infections were determined by positive microbial culture. One-year mortality was assessed by telephone interview. Factors associated with glucagon-like peptide 1 were determined by multivariable linear logistic regression. Predicting the clinical importance of glucagon-like peptide 1 on the development of hospital-acquired infections and mortality were determined by Cox proportional hazards models and further by receiver operating characteristic curve analysis. Kaplan-Meier analyses were performed to examine whether the mean glucagon-like peptide 1 level of the cohort could discriminate the hospital-acquired infections-free survival.

RESULTS

Median burn size was 41% (19%-70%) of total body surface area. Hospital-acquired infections developed in 36 (25%) patients after a mean of 10 ± 1 days after injury. Interleukin 6, monocyte chemotactic protein-1, and blood urea nitrogen levels and thrombin time were independently associated with increased glucagon-like peptide 1 levels. Levels of glucagon-like peptide 1 (median, interquartile range) were greater in patients who developed hospital-acquired infections than in those who did not (237 pmol/L, 76-524 vs 80 pmol/L, 51-158; P < .001) and in patients who died (536 pmol/L, interquartile range: 336-891 pmol vs 98 pmol/L, 47-189; P < .001). Although the glucagon-like peptide 1 level could not predict hospital-acquired infections-free survival in individual patients, it could predict 1-year mortality independently (P = .021). Moreover, a glucagon-like peptide 1 level of 200 pmol/L could discriminate hospital-acquired infections-free survival (P < .001).

CONCLUSION

Admission glucagon-like peptide 1 level can discriminate hospital-acquired infections-free survival and predict long-term mortality in a group of patients with burn injury. Our data suggests that glucagon-like peptide 1 may be a predictive biomarker for hospital-acquired infections and mortality in burn patients.

Weight loss induced by whole grain-rich diet is through a gut microbiota-independent mechanism

The prevalence of overweight and obesity has increased worldwide. Obesity is a well-known risk factor of type 2 diabetes mellitus and cardiovascular disease and raises public health concerns. Many dietary guidelines encourage the replacement of refined grains with whole grains (WGs) to enhance body weight management. Current evidence regarding interrelationships among WGs, body weight, and gut microbiota is limited and inconclusive. In this editorial, we comment on the article by Roager et al published in the recent issue of the Gut 2019; 68(1): 83-93. In the study, obese patients (25 < body mass index < 35 kg/m²) were randomly assigned to receive two 8-wk dietary controlling periods with WGs and refined grain-rich diet. The results showed significantly decreased body weight in the WG group. Either the composition of gut microbiota or short-chain fatty acids, the leading end product of fermentation of non-digestible carbohydrate by gut microbiota, did not differ between the two groups. The study highly indicated that a WG-rich diet reduced body weight independent of gut microbiota. We then raised some plausible mechanisms of how WGs might influence body weight and demonstrated more literature in line with WGs enhance body weight control through a microbiota-independent pathway. Possible mechanisms include: (1) The abundant dietary fiber contents of WGs increase satiety, satiation, energy excretion from stool, and energy expenditure simultaneously decreasing energy absorption and fat storage; (2) The plentiful amount of polyphenols of WGs improve energy expenditure by hampering adipocyte maturation and function; (3) The sufficient magnesium and zinc of WGs guarantee lean body mass growth and decrease fat mass; (4) The effect of WGs on brown adipose tissue is a key component of non-shivering thermogenesis; and (5) The increase of adiponectin by WGs enhances glucose utilization, lipid oxidation, and energy expenditure.

Ghrelin abates bacterial translocation following burn injury by improving gastric emptying

BACKGROUND

In severe burns, increased intestinal permeability facilitates bacterial translocation, resulting in systemic endotoxemia and multi^- organ failure. We investigated the role of burn-induced gastrointestinal dysmotility (BIGD) in promoting bacterial translocation following burn injury, and the protective effect of ghrelin in this process.

METHODS

We assessed gastric emptying (GE%) and intestinal transit (IT by geometric center "GC") in a 60% total body surface area scald burn rat model and measured bacterial counts in mesenteric lymph nodes (MLN) and distal small intestine by colony-forming unit per gram of tissue (CFU/g). A group of animals was treated with ghrelin or saline after burn.

KEY RESULTS

Scald burn was associated with a significant delay in GE (62% ± 4% vs 74% ± 4%; P = .02) and a trend of delay in intestinal transit (GC: 5.5 ± 0.1 vs 5.8 ± 0.2; P = .09). Concurrently, there was a marginal increase in small intestinal bacterial overgrowth (6 × 10⁵ vs 2 × 10⁵  CFU/g; P = .05) and significant translocation to MLN (2 × 10² vs 4 × 10¹ ; P = .03). We observed a negative correlation between GE and intestinal bacterial overgrowth (r_s  = -0.61; P = .002) and between IT and translocation (r_s  = -0.63; P = .004). Ghrelin administration significantly accelerated GE following burn injury (91% ± 3% vs 62% ± 4; P = .03), reduced small intestinal bacterial overgrowth, and completely inhibited translocation to MLN (0.0 vs 5 × 10² ; P = .01).

CONCLUSIONS & INFERENCES

Burn-induced gastrointestinal dysmotility is correlated with the systemic translocation of gram-negative gut bacteria that are implicated in multiple organ failure in burn patients. Therapeutic interventions to restore BIGD are warranted (Neurogastroenterol Motil, 2012, 24, 78).

Burn-Induced Impairment of Ileal Muscle Contractility Is Associated with Increased Extracellular Matrix Components

INTRODUCTION

Severe burns lead to marked impairment of gastrointestinal motility, such as delayed gastric emptying and small and large intestinal ileus. However, the cellular mechanism of these pathologic changes remains largely unknown.

METHODS

Male Sprague Dawley rats approximately 3 months old and weighing 300-350 g were randomized to either a 60% total body surface area full-thickness scald burn or sham procedure and were sacrificed 24 h after the procedure. Gastric emptying, gastric antrum contractility ileal smooth muscle contractility, and colonic contractility were measured. Muscularis externa was isolated from the ileal segment to prepare smooth muscle protein extracts for Western blot analysis.

RESULTS

Compared with sham controls, the baseline rhythmic contractile activities of the antral, ileal, and colonic smooth muscle strips were impaired in the burned rats. Simultaneously, our data showed that ileal muscularis ECM proteins fibronectin and laminin were significantly up-regulated in burned rats compared with sham rats. TGF-β signaling is an important stimulating factor for ECM protein expression. Our results revealed that TGF-β signaling was activated in the ileal muscle of burned rats evidenced by the activation of Smad2/3 expression and phosphorylation. In addition, the total and phosphorylated AKT, which is an important downstream factor of ECM signaling in smooth muscle cells, was also up-regulated in burned rats' ileal muscle. Notably, these changes were not seen in the colonic or gastric tissues.

CONCLUSION

Deposition of fibrosis-related proteins after severe burn is contributors to decreased small intestinal motility.