Potential role of adipose tissue and its hormones in burns and critically III patients

Adipokines-A Cohort Prospective Study in Children with Severe Burns

Burns generate every year an important burden of morbidity, being a major global public health problem through prolonged hospitalization, complications, and increased mortality. This study's purpose was to evaluate the serum levels of three adipokines and to establish significant correlations with other circulating molecules and with some clinical parameters. We evaluated 32 children with severe burns (over 25% total burned surface area-TBSA) at 48 h, day 10, and day 21 post burn, and 21 controls. The serum levels of adiponectin, resistin, leptin, tumor necrosis factor-α (TNF-α), plasminogen activator inhibitor-1 (PAI-1), and C-reactive protein (CRP) (among nine other biochemical parameters) were detected by Multiplex technique. Significant statistical differences were obtained for resistin and leptin compared to the control group, in different moments of measurements. Adiponectin serum levels presented statistically significant correlations with hot liquid mechanism of burn, the Revised Baux score, TBSA, resistin, PAI-1, CRP, TNF-α, and triglycerides (TGLs) serum levels. Resistin serum levels presented statistically significant correlations with adiponectin, CRP, PAI-1, leptin, and TNF-α. Additionally, we found statistically significant correlations between leptin serum levels and length of hospitalization, TNF-α, resistin, adiponectin, and PAI-1 serum levels. In severely burned children, adiponectin, resistin, and leptin specifically correlate with clinical parameters and with proteins involved in the systemic inflammatory response and the hypermetabolic response.

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.

Examining Obesity and Its Association With Burn Injury: A Secondary Analysis of the Transfusion Requirement in Burn Care Evaluation Study

INTRODUCTION

Literature examining the connection between obesity and burn injuries is limited. This study is a secondary analysis of a multicenter trial data set to investigate the association between burn outcomes and obesity following severe burn injury.

MATERIALS AND METHODS

Body mass index (BMI) was used to stratify patients as normal weight (NW; BMI 18.5-25), all obese (AO; any BMI>30), obese I (OI; BMI 30-34.9), obese II (OII; BMI 35-39.9), or obese III (OIII; BMI>40). The primary outcome examined was mortality. Secondary outcomes included hospital length of stay (LOS), number of transfusions, injury scores, infection occurrences, number of operations, ventilator days, intensive care unit LOS, and days to wound healing.

RESULTS

Of 335 patients included for study, 130 were obese. Median total body surface area (TBSA) was 31%, 77 patients (23%) had inhalation injury and 41 patients died. Inhalation injury was higher in OIII than NW (42.1% versus 20%, P = 0.03). Blood stream infections (BSI) were higher in OI versus NW (0.72 versus 0.33, P = 0.03). Total operations, ventilator days, days to wound healing, multiorgan dysfunction score, Acute Physiology and Chronic Health Evaluationscore, hospital LOS, and intensive care unit LOS were not significantly affected by BMI classification. Mortality was not significantly different between obesity groups. Kaplan-Meier survival curves did not significantly differ between the groups (χ2 = 0.025, P = 0.87). Multiple logistic regression identified age, TBSA, and full thickness burn as significant independent predictors (P < 0.05) of mortality; however, BMI classification itself was not predictive of mortality.

CONCLUSIONS

No significant association between obesity and mortality was seen after burn injury. Age, TBSA, and percent full- thickness burn were independent predictors of mortality after burn injury, while BMI classification was not.

Bone Marrow Adipokine Expression Was Associated With Decreased Erythroid Colony Growth After Trauma

Background

Proinflammatory and immunomodulatory adipokines are linked to inflammation in critically ill patients but are poorly studied after injury. We hypothesized that trauma would induce systemic adipokine release and influence erythroid suppression.

Methods

Blood and bone marrow (BM) were collected from trauma patients (ISS > 15, n = 90) and compared to patients undergoing elective hip replacement (n = 37). Plasma adipokine levels were measured, and BM was assayed for adipokine transcription and erythroid progenitor growth potential. Differences were detected using t-tests and correlations using simple linear regression.

Results

Trauma patients exhibited decreased adiponectin (1.8* vs 3.4 mg/mL) and increased leptin (7.8* vs 4.6 ng/mL) and resistin (3.1* vs 2.5 ng/mL), with sex- and age-specific differences. They also showed increased BM visfatin transcription. Adipokine transcription negatively correlated with erythroid progenitor growth.

Conclusion

Adipose tissue activity is linked to inflammatory responses after injury, with variability by age and sex. Bone marrow adipose tissue may influence erythroid recovery after trauma.

Adipose tissue: a neglected organ in the response to severe trauma?

Despite the manifold recent efforts to improve patient outcomes, trauma still is a clinical and socioeconomical issue of major relevance especially in younger people. The systemic immune reaction after severe injury is characterized by a strong pro- and anti-inflammatory response. Besides its functions as energy storage depot and organ-protective cushion, adipose tissue regulates vital processes via its secretion products. However, there is little awareness of the important role of adipose tissue in regulating the posttraumatic inflammatory response. In this review, we delineate the local and systemic role of adipose tissue in trauma and outline different aspects of adipose tissue as an immunologically active modifier of inflammation and as an immune target of injured remote organs after severe trauma.

Resistin forms a network with inflammatory cytokines and is associated with prognosis in major burns

BACKGROUND

In current intensive care treatment, some patients with severe burns cannot be saved due to progressive organ failure. Further investigation of the pathogenesis of severe burns is needed to improve the mortality rate. In burns, inflammatory cytokines form a network that leads to an inflammatory response. Adipocytes secrete physiologically active substances (adipokines). The roles of adipokines have not been completely clarified in burn patients. This study aimed to determine the relation between serial changes of adipokines and clinical course in severely burned patients.

METHODS

This was a single-center, retrospective, observational study. Patients' blood samples were collected on the day of injury and around 1 week later. Adipokines (adiponectin, angiotensinogen, chemerin, CXCL-12/SDF-1, leptin, resistin, vaspin, visfatin), various inflammatory cytokines, syndecan-1 and C1 esterase inhibitor were measured.

RESULTS

Thirty-eight patients were included. Resistin levels were significantly higher in the non-survivors versus survivors on Day 1 after burn injury. Hierarchical clustering analysis showed common clusters on Day 1 and at 1 Week after burn injury (resistin, IL-6, IL-8, IL10 and MCP-1). The correlation coefficient of resistin to SOFA score at 1 Week was significant. Logistic regression analysis showed a significant relation of resistin levels on Day 1 with prognosis; the area under the ROC curve for resistin was 0.801.

CONCLUSIONS

In the acute phase of burns, resistin was associated with other pro-inflammatory cytokines and was related to the severity and prognosis of major burns.

Adipose tissue versus stem cell-derived small extracellular vesicles to enhance the healing of acute burns

Aim: Proper healing of extensive burns remains a healthcare challenge. In the present study, we proposed a distinct therapeutic application of adipose tissue and small extracellular vesicles isolated from human menstrual blood-derived mesenchymal stem cells (MenSC) small extracellular vesicles (sEVs) to enhance the repair of third-degree burn injury. Materials & methods: Mouse model of third-degree burn was used. Adipose tissue in the form of nano-fat (NF) and MenSC-sEVs was injected subcutaneously at the site of injuries. Results: NF and sEVs were capable of enhancing wound closure and increasing neoangiogenesis. NF was also effective in accelerating the formation of granulation tissue and boosting the thickness of the new epithelial layer. Conclusion: This study demonstrates the effectiveness of NF and MenSC-sEVs as promising therapeutic approaches to facilitate the repair of skin burns.

Adipose saturation reduces lipotoxic systemic inflammation and explains the obesity paradox

Obesity sometimes seems protective in disease. This obesity paradox is predominantly described in reports from the Western Hemisphere during acute illnesses. Since adipose triglyceride composition corresponds to long-term dietary patterns, we performed a meta-analysis modeling the effect of obesity on severity of acute pancreatitis, in the context of dietary patterns of the countries from which the studies originated. Increased severity was noted in leaner populations with a higher proportion of unsaturated fat intake. In mice, greater hydrolysis of unsaturated visceral triglyceride caused worse organ failure during pancreatitis, even when the mice were leaner than those having saturated triglyceride. Saturation interfered with triglyceride's interaction and lipolysis by pancreatic triglyceride lipase, which mediates organ failure. Unsaturation increased fatty acid monomers in vivo and aqueous media, resulting in greater lipotoxic cellular responses and organ failure. Therefore, visceral triglyceride saturation reduces the ensuing lipotoxicity despite higher adiposity, thus explaining the obesity paradox.