Protective effects of pentoxifylline on the brain following remote burn injury

The impact of burn injury on the central nervous system

Burn injuries can be devastating, with life-long impacts including an increased risk of hospitalization for a wide range of secondary morbidities. One area that remains not fully understood is the impact of burn trauma on the central nervous system (CNS). This review will outline the current findings on the physiological impact that burns have on the CNS and how this may contribute to the development of neural comorbidities including mental health conditions. This review highlights the damaging effects caused by burn injuries on the CNS, characterized by changes to metabolism, molecular damage to cells and their organelles, and disturbance to sensory, motor and cognitive functions in the CNS. This damage is likely initiated by the inflammatory response that accompanies burn injury, and it is often long-lasting. Treatments used to relieve the symptoms of damage to the CNS due to burn injury often target inflammatory pathways. However, there are non-invasive treatments for burn patients that target the functional and cognitive damage caused by the burn, including transcranial magnetic stimulation and virtual reality. Future research should focus on understanding the mechanisms that underpin the impact of a burn injury on the CNS, burn severity thresholds required to inflict damage to the CNS, and acute and long-term therapies to ameliorate deleterious CNS changes after a burn.

Use of extracorporeal membrane oxygenation in children with burn injury: Case report and literature review

RATIONALE

Burns are one of the most debilitating injuries in the world and one of the major causes of accidental disability and death among children. Severe burns can result in irreversible brain damage, placing patients at high risk of brain failure and high mortality. Therefore, timely diagnosis and treatment of burn encephalopathy are crucial for improving prognosis. In recent years, extracorporeal membrane oxygenation (ECMO) has been increasingly used to improve the prognosis of patients with burns. Here, we report a case of ECMO treatment in a child with burns and review the relevant literature.

PATIENT CONCERNS

A 7-year-old boy with a modified Baux score of 24 presented with asphyxia, loss of consciousness, refractory hypoxemia, and malignant arrhythmia after smoke inhalation for 1 day. Fiberoptic bronchoscopy revealed a large amount of black carbon-like substances aspirated from the trachea.

DIAGNOSES

Considering that the boy inhaled a large amount of smoke, the clinical manifestation was unclear consciousness, laboratory examination revealed continuous low blood oxygen saturation, and bronchoscopy revealed a large amount of black carbon-like substances in the trachea, thereby leading to the diagnosis of asphyxia, inhalation pneumonia, burn encephalopathy, multiple organ dysfunction syndrome, and malignant arrhythmia. In addition, pulmonary edema and carbon monoxide poisoning are caused by chemical agents, gas fumes, and vapors.

INTERVENTIONS

The boy's blood oxygen saturation and blood circulation remained unstable despite various ventilation methods and medications, thus we decided to use ECMO. After 8 days of ECMO support, the patient was successfully weaned from the machine.

OUTCOMES

Under the application of ECMO, the respiratory and circulatory systems significantly improved. Nevertheless, due to the progressive brain injury caused by burns and the poor prognosis, the parents ceased all treatment and the boy passed away.

LESSONS

This case report demonstrates that brain edema and herniation can arise as phenotypes of burn encephalopathy, which is a challenge to treat in children. Children with confirmed or suspected burn encephalopathy should undergo diagnostic tests completed as soon as possible to confirm the diagnosis. After receiving ECMO treatment, the respiratory and circulatory systems of the burn victims reported significantly improved. Hence, ECMO is a viable alternative for supporting patients with burns.

Pathological changes in the brain after peripheral burns

Brain injuries are common complications in patients with thermal burns and are associated with unpleasant outcomes. In clinical settings, it was once believed that brain injuries were not major pathological processes after burn, at least in part due to the unavailability of specific clinical manifestations. Burn-related brain injuries have been studied for more than a century, but the underlying pathophysiology has not been completely clarified. This article reviews the pathological changes in the brain following peripheral burns at the anatomical, histological, cytological, molecular and cognitive levels. Therapeutic indications based on brain injury as well as future directions for research have been summarized and proposed.

Experimental models for controlled burn injuries in rats: a systematic analysis of original methods and burn devices

AIM

Despite a wide variety of models found in literature, choosing the right one can be difficult as many of them are lacking precise methodology. This study aims to analyze and compare original burn models in terms of burn device and technique, parameters, and wound depth assessment.

METHODS

A systematic search was performed according to PRISMA guidelines on studies describing original experimental burn models in rats. The adapted PICO formula and ARRIVE checklist were followed for inclusion and assessment of quality of studies. Characteristics of animals, burn technique, burn parameters and method of histological confirmation of burn depth were recorded.

RESULTS

Twenty-seven studies were included in the final analysis. Most studies used direct contact with skin for burn infliction (n=20). The rat's dorsum was the most common site (n=18). Ten studies used manually controlled burn devices, while ten designed automatic burn devices with control over temperature (n=10), exposure time (n=5), and pressure (n=5). Most studies (n=7) used a single biopsy taken from the center of the wound to confirm burn depth immediately after burn infliction.

CONCLUSION

From the wide variety of burn models in current literature, our study provides an overview of the most relevant experimental burn models in rats aiding researchers to understand what needs to be addressed when designing their burn protocol. Models cannot be compared as burn parameters variate significantly. Assessment of burn depth should be done in a standardized, sequential fashion in future burn studies to increase reproducibility.

Irisin Gene Delivery Ameliorates Burn-Induced Sensory and Motor Neuropathy

Burn-related neuropathy is common and often involves pain, paresthesia, or muscle weakness. Irisin, an exercise-induced myokine after cleavage from its membrane precursor fibronectin type III domain-containing 5 (FNDC5), exhibits neuroprotective and anti-inflammatory activities. A rat model of third-degree burn on the right hind paw was used to investigate the therapeutic role of irisin/FNDC5. Rats received burn injury and were treated with intrathecal recombinant adenovirus containing the irisin sequence (Ad-irisin) at 3 weeks postburn. One week later, mechanical allodynia was examined. The expression of irisin in cerebrospinal fluid (CSF) was detected. Ipsilateral gastrocnemius muscle and lumbar spinal cord were also obtained for further investigation. Furthermore, the anti-apoptotic effect of recombinant irisin in SH-SY5Y cells was evaluated through tumor necrosis factor alpha (TNFα) stimulus to mimic burn injury. We noted intrathecal Ad-irisin attenuated pain sensitization and gastrocnemius muscle atrophy by modulating the level of irisin in CSF, and the expression of neuronal FNDC5/irisin and TNFα in the spinal cord. Ad-irisin also ameliorated neuronal apoptosis in both dorsal and ventral horns. Furthermore, recombinant irisin attenuated TNFα-induced SH-SY5Y cell apoptosis. In summary, irisin attenuated allodynia and muscle wasting by ameliorating neuroinflammation-induced neuronal apoptosis.

Burn injury and long-term nervous system morbidity: a population-based cohort study

OBJECTIVE

To investigate if children and adults who are hospitalised for a burn injury have increased long-term hospital use for nervous system diseases.

DESIGN

A population-based retrospective cohort study using linked administrative health data from the Western Australian Data Linkage System.

PARTICIPANTS

Records of 30 997 persons hospitalised for a first burn injury in Western Australia during the period 1980-2012, and 123 399 persons who were age and gender frequency matched with no injury admissions randomly selected from Western Australia's birth registrations and electoral roll.

MAIN OUTCOME MEASURES

Admission rates and summed length of stay for nervous system diseases. Negative binomial and Cox proportional hazards regression modelling were used to generate incidence rate ratios (IRRs) and HRs with 95% CIs, respectively.

RESULTS

After adjustment for demographic factors and pre-existing health status, the burn injury cohort had 2.20 times (95% CI 1.86 to 2.61) as many nervous system admissions and 3.25 times the number of days in hospital (95% CI: 2.28 to 4.64) than the uninjured cohort. This increase was found for those who had sustained burns during childhood (<15 years: IRR, 95% CI: 1.97, 1.49 to 2.61) and early to mid-adulthood (15-45 years: IRR, 95% CI: 2.70, 2.06 to 3.55) and older adults (≥45 years: IRR, 95% CI: 1.62, 1.33 to 1.97). Significantly elevated first-time postburn admissions were observed for children for 15 years postburn discharge (0-5 years: HR, 95% CI: 1.97, 1.75 to 2.22; 5-15 years: HR, 95% CI: 1.44, 1.28 to 1.63) and for adults 45 years and older at index burn for 5 years postburn only (HR, 95% CI: 1.72, 1.42 to 2.09).

CONCLUSIONS

Burn injury appears to be associated with increased nervous system-related morbidity for many years after burn injury. Further work into the mechanisms and possible treatments to reduce this morbidity are warranted in light of these findings.

Protective effects of pentoxifylline on lipopolysaccharide-induced white matter injury in a rat model of periventricular leukomalasia

OBJECTIVE

To investigate the potential neuroprotective effect of maternal pentoxifylline (PNTX) treatment in endotoxin-induced periventricular leukomalasia (PVL) in the developing rat brain.

METHOD

Intraperitoneal injection of lipopolysaccharide was administered on two of three Wistar pregnant rats to establish PVL. To obtain PNTX-treated group, one of the two dams were injected with PNTX. The control group was treated with saline. Rat pups were grouped as control, maternal LPS-treated group and PNTX + LPS-treated group. At 7th postnatal days, apoptosis and hypomyelination were evaluated. Apoptosis was evaluated by caspase-3 and terminal deoxynucleotidyl transferase [TdT] dUTP nick endlabelling reaction (TUNEL) immunostaining. To assess hypomyelination, myelin basic protein (MBP) staining, as a marker of myelination, was evaluated.

RESULTS

MBP staining was significantly less and weaker in the brains of the LPS-treated group as compared with the PNTX-treated group. PNTX treatment significantly reduced the number of apoptotic cells in the periventricular WM shown on Tunel and caspase-3.

CONCLUSIONS

Presented study is first indicated that PNTX may provide protection against an LPS-induced inflammatory response and WMI in the developing rat brain. Our results also suggest that PNTX treatment in pregnant women with maternal or placental infection may minimize the risk of PVL and cerebral palsy.

Pentoxifylline and the proteasome inhibitor MG132 induce apoptosis in human leukemia U937 cells through a decrease in the expression of Bcl-2 and Bcl-XL and phosphorylation of p65

Background

In Oncology, the resistance of the cancerous cells to chemotherapy continues to be the principal limitation. The nuclear factor-kappa B (NF-κB) transcription factor plays an important role in tumor escape and resistance to chemotherapy and this factor regulates several pathways that promote tumor survival including some antiapoptotic proteins such as Bcl-2 and Bcl-XL. In this study, we investigated, in U937 human leukemia cells, the effects of PTX and the MG132 proteasome inhibitor, drugs that can disrupt the NF-κB pathway. For this, we evaluated viability, apoptosis, cell cycle, caspases-3, -8, -9, cytochrome c release, mitochondrial membrane potential loss, p65 phosphorylation, and the modification in the expression of pro- and antiapoptotic genes, and the Bcl-2 and Bcl-XL antiapoptotic proteins.

Results

The two drugs affect the viability of the leukemia cells in a time-dependent manner. The greatest percentage of apoptosis was obtained with a combination of the drugs; likewise, PTX and MG132 induce G1 phase cell cycle arrest and cleavage of caspases -3,-8, -9 and cytochrome c release and mitochondrial membrane potential loss in U937 human leukemia cells. In these cells, PTX and the MG132 proteasome inhibitor decrease p65 (NF-κB subunit) phosphorylation and the antiapoptotic proteins Bcl-2 and Bcl-XL. We also observed, with a combination of these drugs overexpression of a group of the proapoptotic genes BAX, DIABLO, and FAS while the genes BCL-XL, MCL-1, survivin, IκB, and P65 were downregulated.

Conclusions

The two drugs used induce apoptosis per se, this cytotoxicity was greater with combination of both drugs. These observations are related with the caspases -9, -3 cleavage and G1 phase cell cycle arrest, and a decrease in p65 phosphorylation and Bcl-2 and Bcl-XL proteins. As well as this combination of drugs promotes the upregulation of the proapoptotic genes and downregulation of antiapoptotic genes. These observations strongly confirm antileukemic potential.