Thromboprophylaxis in pediatric patients with earthquake-related crush syndrome: a single centre experience.

PURPOSE: Injuries increase the risk of venous thromboembolism (VTE). However, the literature on the management of anticoagulant therapy in pediatric patients with crush injury is limited. In this study, we aimed to share our experience about anticoagulant thromboprophylaxis in pediatric patients with earthquake-related crush syndrome. METHODS: This study included patients who were evaluated for VTE risk after the Turkey-Syria earthquake in 2023. Since there is no specific pediatric guideline for the prevention of VTE in trauma patients, risk assessment for VTE and decision for thromboprophylaxis was made by adapting the guideline for the prevention of perioperative VTE in adolescent patients. RESULTS: Forty-nine patients [25 males and 24 females] with earthquake-related crush syndrome had participated in the study. The median age of the patients was 13.5 (8.8-15.5) years. Seven patients (14.6%) who had no risk factors for thrombosis were considered to be at low risk and did not receive thromboprophylaxis. Thirteen patients (27.1%) with one risk factor for thrombosis were considered to be at moderate risk and 28 patients (58.3%) with two or more risk factors for thrombosis were considered to be at high risk. Moderate-risk patients (n = 8) and high-risk patients aged < 13 years (n = 11) received prophylactic enoxaparin if they could not be mobilized early, while all high-risk patients aged ≥ 13 years (n = 13) received prophylactic enoxaparin. CONCLUSION: With the decision-making algorithm for thyromboprophylaxis we used, we observed a VTE rate of 2.1% in pediatric patients with earthquake-related crush syndrome.

Precision engineered peptide targeting leukocyte extracellular traps mitigate acute kidney injury in Crush syndrome.

Crush syndrome induced by skeletal muscle compression causes fatal rhabdomyolysis-induced acute kidney injury (RIAKI) that requires intensive care, including hemodialysis. However, access to crucial medical supplies is highly limited while treating earthquake victims trapped under fallen buildings, lowering their chances of survival. Developing a compact, portable, and simple treatment method for RIAKI remains an important challenge. Based on our previous finding that RIAKI depends on leukocyte extracellular traps (ETs), we aimed to develop a novel medium-molecular-weight peptide to provide clinical treatment of Crush syndrome. We conducted a structure-activity relationship study to develop a new therapeutic peptide. Using human peripheral polymorphonuclear neutrophils, we identified a 12-amino acid peptide sequence (FK-12) that strongly inhibited neutrophil extracellular trap (NET) release in vitro and further modified it by alanine scanning to construct multiple peptide analogs that were screened for their NET inhibition ability. The clinical applicability and renal-protective effects of these analogs were evaluated in vivo using the rhabdomyolysis-induced AKI mouse model. One candidate drug [M10Hse(Me)], wherein the sulfur of Met10 is substituted by oxygen, exhibited excellent renal-protective effects and completely inhibited fatality in the RIAKI mouse model. Furthermore, we observed that both therapeutic and prophylactic administration of M10Hse(Me) markedly protected the renal function during the acute and chronic phases of RIAKI. In conclusion, we developed a novel medium-molecular-weight peptide that could potentially treat patients with rhabdomyolysis and protect their renal function, thereby increasing the survival rate of victims affected by Crush syndrome.

Zinc chelator treatment in crush syndrome model mice attenuates ischemia-reperfusion-induced muscle injury due to suppressing of neutrophil infiltration.

In crush syndrome, massive muscle breakdown resulting from ischemia-reperfusion muscle injury can be a life-threatening condition that requires urgent treatment. Blood reperfusion into the ischemic muscle triggers an immediate inflammatory response, and neutrophils are the first to infiltrate and exacerbate the muscle damage. Since free zinc ion play a critical role in the immune system and the function of neutrophils is impaired by zinc depletion, we hypothesized that the administration of a zinc chelator would be effective for suppressing the inflammatory reaction at the site of ischemia-reperfusion injury and for improving of the pathology of crush syndrome. A crush syndrome model was created by using a rubber tourniquet to compress the bilateral hind limbs of mice at 8 weeks. A zinc chelator N,N,N',N'-tetrakis-(2-pyridylmethyl)-ethylenediamine (TPEN) was administered immediately after reperfusion in order to assess the anti-inflammatory effect of the chelator for neutrophils. Histopathological evaluation showed significantly less muscle breakdown and fewer neutrophil infiltration in TPEN administration group compared with control group. In addition, the expression levels of inflammatory cytokine and chemokine such as IL-6, TNFα, CXCL1, CXCL2, CXCR2, CCL2 in ischemia-reperfusion injured muscle were significantly suppressed with TPEN treatment. Less dilatation of renal tubules in histological evaluation in renal tissue and significantly better survival rate were demonstrated in TPEN treatment for ischemia-reperfusion injury in crush syndrome. The findings of our study suggest that zinc chelators contributed to the resolution of exacerbation of the inflammatory response and attenuation of muscle breakdown in the acute phase after crush syndrome. In addition, our strategy of attenuation of the acute inflammatory reaction by zinc chelators may provide a promising therapeutic strategy not only for crush syndrome, but also for other diseases driven by inflammatory reactions.

Immunomodulatory role of recombinant human erythropoietin in acute kidney injury induced by crush syndrome via inhibition of the TLR4/NF-κB signaling pathway in macrophages.

Objective: The present study aimed to investigate whether recombinant human erythropoietin (rHuEPO) plays an immunomodulatory function by regulating the TLR4/NF-κB signaling pathway.Materials and methods: C57BL/6 mice were intraperitoneally injected with rHuEPO and, half an hour later, with 50% glycerol at the dose of 7.5 ml/kg to induce crush syndrome (CS)-acute kidney injury (AKI). The levels of TNF-α, IL-1ß, IL-6, serum creatinine (Scr), and creatine kinase (CK) were measured. The kidney tissues were analyzed by HE staining, and macrophage infiltration was detected by immunohistochemistry. Double immunofluorescence staining, RT-qPCR, and western blotting were conducted to analyze TLR4/NF-κB p65 expression. Ferrous myoglobin was co-cultured with RAW264.7 cells to mimic crush injury and the production of proinflammatory cytokines. The expression levels of TLR4 and NF-κB p65 were measured.Results: In vivo study results revealed that rHuEPO ameliorated renal function, tissue damage, production of proinflammatory cytokines, and macrophage infiltration in the kidneys. The protein and mRNA expression levels of genes involved in the TLR4/NF-κB signaling pathway in CS-induced AKI mice were upregulated (p < .05). Meanwhile, the expression levels of TLR4, NF-κB p65, and proinflammatory cytokines in RAW264.7 cells were downregulated in CS-AKI mice injected with rHuEPO (p < .05).Conclusions: Our results demonstrated the immunomodulatory capacity of rHuEPO and confirmed that rHuEPO exerts protective effects against CS-induced AKI by regulating the TLR4/NF-κB signaling pathway in macrophages. Therefore, our findings highlight the therapeutic potential of rHuEPO in improving the prognosis of CS-AKI patients.

Early Therapeutic Intervention for Crush Syndrome: Characterization of Intramuscular Administration of Dexamethasone by Pharmacokinetic and Biochemical Parameters in Rats.

Crush syndrome (CS) is the systemic manifestation of muscle cell damage resulting from pressure and crushing. It is associated with a high mortality rate, even when patients are treated with conventional therapy. We demonstrated the utility of intramuscular administration of dexamethasone (DEX) in disaster medical care by using a model of CS to characterize the pharmacokinetics and biochemical parameters. We compared intravenous (IV) and intramuscular (IM) injection. The IM sites were the right anterior limb (AL), bilateral hind limbs (bHL), and unilateral hind limb (uHL). DEX (5.0 mg/kg) was administered in sham-operated (sham, S-IV, S-AL, S-bHL, S-uHL groups) and CS rats (control, C-IV, C-AL, C-bHL, C-uHL groups). The survival rate in the IM groups was lower than that in the C-IV group. Survival was highest in the C-AL group, followed by the C-uHL and C-bHL groups. The blood DEX concentration of the C-AL group was similar to that in the C-IV group. The C-bHL and C-uHL groups had decreased blood DEX concentrations. Moreover, inhibition of inflammation was related to these changes. Administration of DEX to non-injured muscle, as well as IV administration, increased the survival rate by modulating shock and inflammatory mediators, consequently suppressing myeloperoxidase activity and subsequent systemic inflammation, resulting in a complete recovery of rats from lethal CS. These results demonstrate that injection DEX into the non-injured muscle is a potentially effective early therapeutic intervention for CS that could easily be used in transport to the hospital.

Effects of acetaminophen and mannitol on crush injuries in rats: An experimental study.

BACKGROUND: The present objective was to evaluate effects of acetaminophen and mannitol on renal function and histopathology in crush injuries. METHODS: Thirty-six rats weighing 370-400 g each were used. No surgery was performed on the first (control) group. The gastrocnemius muscle regions of each rat in the remaining 5 groups were compressed for 2 or 24 hours. In the 4th group, 100 mg/kg acetaminophen was intraperitoneally administered. In the 5th group, 1 g/kg mannitol was administered. In the 6th group, 100 mg/kg acetaminophen and 1 g/kg mannitol were administered. RESULTS: No statistically significant differences were observed among the treatment groups in terms of sodium, potassium, alanine aminotransferase (ALT), and average creatinine clearance values. Hydropic degeneration, tubular necrosis, presence of immunoperoxidase and myoglobin, tubulus epithelial cell degeneration, and presence of PAS-dyed material in tubular lumen was more prominently decreased in the acetaminophen group than the mannitol group. Improvement was observed in the group that was administered both drugs, compared to the mannitol-only group, though findings were still worse than those of the group administered acetaminophen only. CONCLUSION: In crush injuries, acetaminophen improves histopathological renal damage better than mannitol. When used in conjunction with mannitol, the toxic effect of acetaminophen on the liver is decreased.

The Beneficial Effects of ETS-GS, a Novel Vitamin E Derivative, on a Rat Model of Crush Injury.

Crush syndrome is a devastating condition leading to multiple organ failure. The mechanisms by which local traumatic injuries affect distant organs remain unknown. ETS-GS is a novel water-soluble, stable anti-oxidative agent composed of vitamin E derivative. Given that one of the main pathophysiological effects in crush syndrome is massive ischemia-reperfusion, reactive oxygen species (ROS) generated from the injured extremities would be systemically involved in distant organ damage. We investigated whether ETS-GS could suppress inflammatory response and improve mortality in a rat model of crush injury. Crush injury was induced by compression of bilateral hindlimbs for 6 h followed by release of compression. Seven-day survival was significantly improved by ETS-GS treatment. To estimate anti-oxidative and anti-inflammatory effects of ETS-GS, serum was collected 6 and 20 h after the injury. ETS-GS treatment significantly dampened the up-regulation of malondialdehyde and reduction of superoxide dismutase in the serum, which were induced by crush injury. Serum levels of interleukin 6 and high mobility group box 1 were significantly decreased in the ETS-GS group compared with those in the control group. Lung damage shown by hematoxylin-eosin staining at 20 h after the injury was ameliorated by the treatment. Ex vivo imaging confirmed that ETS-GS treatment reduced ROS generation in both the lung and the muscle following crush injury. The administration of ETS-GS could suppress ROS generation, systemic inflammation, and the subsequent organ damage, thus improving survival in a rat model of crush injury. These findings suggest that ETS-GS can become a novel therapeutic agent against crush injury.

Improved angiogenesis and healing in crush syndrome by fibroblast growth factor-2-containing low-molecular-weight heparin (Fragmin)/protamine nanoparticles.

BACKGROUND: We produced fibroblast growth factor (FGF)-2-containing low-molecular-weight heparin (Fragmin)/protamine nanoparticles (FGF-2 + F/P NPs). The purpose of this study was to evaluate the effectiveness of the local administration of FGF-2 + F/P NPs on repairing crush syndrome (CS)-injured lesions after compression release using a nonlethal and reproducible CS injury rat model. MATERIALS AND METHODS: The hind limbs of the anesthetized rats were compressed for 6 h using 3.6 kg blocks, as previously described. The effects of administering FGF-2 + F/P NPs (group A), F/P NPs alone (group B), FGF-2 alone (group C), and saline (control; group D) were examined. Motor function, surface blood flow in the hind limbs, and the wet/dry weight ratio in the tibialis anterior muscle were examined for 1-28 d after the compression release. Histologic analyses were also performed. RESULTS: At the middle and late stages (3-28 d after the compression release), group A had higher scores in the motor function, improved blood flow, increased number of blood vessels, and faster recovered muscle tissue, compared with the other groups. There was no significant difference in enhanced edema in the tibialis anterior muscle among all groups. CONCLUSIONS: The local administration of FGF-2 + F/P NPs to a CS-injured lesion was effective in repairing damaged muscle tissue after compression release.

Acute lethal crush-injured rats can be successfully rescued by a single injection of high-dose dexamethasone through a pathway involving PI3K-Akt-eNOS signaling.

BACKGROUND: Crush syndrome (CS) is characterized by ischemia/reperfusion-induced rhabdomyolysis and the subsequent onset of systemic inflammation. CS is associated with a high mortality, even when patients are treated with conventional therapy. We hypothesized that treatment of lethal CS rat model with dexamethasone (DEX) have therapeutic effects on the laboratory findings and clinical course and outcome. METHODS: To create a CS model, anesthetized rats were subjected to bilateral hind limb compression with rubber tourniquets for 5 hours and randomly divided into three groups as follows: saline-treated CS group, CS groups treated with low (0.1 mg/kg) and high doses (5.0 mg/kg) of DEX. Saline for the CS group or DEX for the DEX-treated CS groups was intravenously administered immediately before reperfusion. Under continuous monitoring and recording of arterial blood pressures, blood and tissue samples were collected for histologic and biochemical analysis at designated period before and after reperfusion. RESULTS: Ischemic compression of rat hind limbs reduced the nitrite content in the crushed muscle, and the subsequent reperfusion induced reactive oxygen species-mediated circulatory collapse and systemic inflammation, finally resulting in a mortality rate of 76% by 48 hours after reperfusion. A single injection of high-dose DEX immediately before reperfusion activated endothelial nitric oxide synthase (eNOS) by sequential phosphorylation through the nongenomic phosphoinositide 3-kinase (PI3K)-Akt-eNOS signaling pathway. DEX also exhibited anti-inflammatory effects by modulating proinflammatory and anti-inflammatory mediators, consequently suppressing myeloperoxidase activities and subsequent systemic inflammation, showing a complete recovery of the rats from lethal CS. CONCLUSION: These results indicate that high-dose DEX reduces systemic inflammation and contributes to the improved survival rate in a rat CS model.

Effect of free radical scavenger on c-jun activation in rats with crush syndrome.

OBJECTIVES: To evaluate the relationship between reactive oxygen species (ROS)-mediated kidney injuries and Jun N-terminal kinase (JNK) activity and the therapeutic effects of tempol in crush syndrome (CS) model rats. METHODS: Male Wister rats were randomly divided into sham operation group (SOG), CS groups (CS6G, CS12G and CS24G) and tempol treatment group (TG, a ROS scavenger). CS model rats were established by crushing the hind limbs of rats with 15 kg pressure for 6 hours, and inferior caval vein blood and kidney samples were harvested at 6, 12, 24 hours after removing crush pressure. In TG, 100 mg/kg tempol was intraperitoneally injected into CS model rats after withdraw of crush pressure. In SOG, rats were fixed on the board without any crush pressure. The activation of c-jun was determined by western blotting. Serological parameters and the content of malondialdehyde (MDA) in kidney tissues were determined by standard methods. RESULTS: Acute kidney injury reached the peak at 12 hours after the crush pressure. Compared with SOG, the content of phosphorylated c-jun was significantly higher in CSG and TG (p < 0.05), and the content of phosphorylated c-jun in the CSG was significantly higher than that in TG (p < 0.05). Interestingly, the changes of the MDA content in the kidney tissues of the 3 groups were similar to the changes of phosphorylated c-jun content. CONCLUSION: ROS-mediated phosphorylation of c-jun may play important roles in the acute kidney injury of CS rats. Tempol can inhibit the phosphorylation of c-jun and alleviate the acute kidney injury.

(-)-Epigallocatechin-3-gallate (EGCG) attenuates peripheral nerve degeneration in rat sciatic nerve crush injury.

Recently, we have shown that green tea (GT) consumption improves both reflexes and sensation in unilateral chronic constriction injury to the sciatic nerve. Considering the substantial neuroprotective properties of GT polyphenols, we sought to investigate whether (-)-epigallocatechin-3-gallate (EGCG) could protect the sciatic nerve and improve functional impairments induced by a crushing injury. We also examined whether neuronal cell apoptosis induced by the crushing injury is affected by EGCG treatment. Histological examination of sciatic nerves from EGCG-treated (50mg/kg; i.p.) showed that axonotmized rats had a remarkable axonal and myelin regeneration with significant decrease in the number of myelinated axonal fibers compared to vehicle-treated crush group. Similarly, ultrastructural evaluation of EGCG-treated nerves displayed normal unmyelinated and myelinated axons with regular myelin sheath thickness and normalized appearance of Schmidt-Lantermann clefts. Extracellular matrix displayed normal collagen fibers appearance with distinctively organized distribution similar to sham animals. Analysis of foot position and extensor postural thrust test showed a progressive and faster recovery in the EGCG-treated group compared to vehicle-treated animals. EGCG-treated rats showed significant increase in paw withdrawal thresholds to mechanical stimulation compared to vehicle-treated crush group. EGCG treatment also restored the mRNA expression of Bax, Bcl-2 and survivin but not that of p53 to sham levels on days 3 and 7 post-injury. Our results demonstrate that EGCG treatment enhanced functional recovery, advanced morphological nerve rescue and accelerated nerve regeneration following crush injury partly due to the down regulation of apoptosis related genes.

Nitrite reduces ischemia/reperfusion-induced muscle damage and improves survival rates in rat crush injury model.

BACKGROUND: Nitrite is an intrinsic signaling molecule with potential therapeutic implications in mammalian ischemia/reperfusion (I/R) injury of the heart, liver, and kidney. Although limb muscle compression and subsequent reperfusion are the causative factors in developing crush syndrome (CS), there has been no report evaluating the therapeutic effects of nitrite on CS. We therefore tested whether nitrite could be a therapeutic agent for the treatment of CS. METHODS: To create a CS model, anesthetized rats were subjected to bilateral hind limb compression with rubber tourniquets for 5 hours, followed by reperfusion for 0 hour to 6 hours while monitoring blood pressure. Saline for the CS group or sodium nitrite (NaNO(2)-100, 200, and 500 µmol/kg) for the nitrite-treated CS groups was intravenously administered immediately before reperfusion. Blood and tissue samples were collected for biochemical analysis. RESULTS: Tissue nitrite levels in injured muscles were significantly reduced in the CS group compared with the sham group during I/R injury. Nitrite administration to CS rats restored nitric oxide bioavailability by enhancing nitrite levels of the muscle, resulting in a reduction of rhabdomyolysis markers such as potassium, lactate dehydrogenase, and creatine phosphokinase. Nitrite treatment also reduced plasma levels of interleukin-6 and myeloperoxidase activities in muscle and lung tissues, finally resulting in a dose-dependent improvement of survival rate from 24% (CS group) to 36% (NaNO(2)-100 group) and 64% (NaNO(2)-200 and 500 groups). CONCLUSION: These results indicate that nitrite reduces I/R-induced muscle damage through its cytoprotective action and contributes to improved survival rate in a rat CS model.

Erythropoietin enhances the regeneration of traumatized tissue after combined muscle-nerve injury.

BACKGROUND: Erythropoietin (EPO) is a pleiotropic cytokine with neuroprotective, anti-inflammatory, and muscle regenerative properties. The purpose of our study was to analyze the regenerative capacity of systemically applied EPO in a combined muscle-nerve injury model. METHODS: We performed a crush injury to the left soleus muscle in 84 male Wistar rats. Using an instrumented clamp, the muscle was crushed over its complete length. Simultaneously, the ipsilateral sciatic nerve was sham manipulated or crushed. Upon induction of the trauma, animals received either EPO (E) (single application of 5,000 IU/kg body weight intraperitonial) or vehicle solution (K). After in vivo assessment of mechanical pain according to Frey, thermal hyperalgesia, latency of nerve conduction velocity, and strength of the soleus muscle were analyzed at days 1, 7, and 42 postinjury (n = 7 per group). Cell proliferation and apoptosis were assessed by means of histology and immunohistochemistry. RESULTS: Combined muscle-nerve injury showed a significant loss of muscle strength, which incompletely recovered within 42 days. Rats treated with EPO showed an increased muscle strength after 7 days and 42 days compared with the control group. Pain behavior was highest in the muscle-nerve injured animals at day 7. EPO decreased the pain and increased nerve conduction velocity. Nerve injury diminished proliferation of muscle cells, whereas simultaneous therapy with EPO resulted in a boost of bromdesoxyuridine-positive cells. CONCLUSIONS: EPO promoted muscle restoration and enhanced nerve recovery after combined muscle-nerve injury. Thus, EPO might represent an attractive therapeutic option to optimize the posttraumatic course after injury.

[Hepatoprotective properties of cytochrome C in traumatic toxicosis].

Experiments on rats showed that traumatic toxicosis (crush syndrome) was accompanied by disorders of both excretion and detoxication functions of the liver and a decrease in the energy potential of the liver. Systemic administration of cytochrome C (10 mg/kg) immediately after trauma and decompression increased the level of endogenous cytochrome C, recovered the pool of adenine nucleotides, normalized bromsulfaleine excretion from the blood, and decreased the content of toxic metabolites in the blood. The obtained experimental data show that cytochrome C possesses high hepatoprotective properties with respect to the development of traumatic toxicosis.

Pregabalin does not impact peripheral nerve regeneration after crush injury.

Timely repair and robust regeneration after traumatic peripheral nerve injury are essential to ensure optimal recovery. Pregabalin (Lyrica; Pfizer Inc., Morris Plains, NJ), frequently prescribed to attenuate neuropathic pain in patients with traumatic nerve injury, was evaluated for its potential to alter nerve regeneration in the rat sciatic crush model. Rats were randomly assigned to one of three groups of 12 animals each: (1) sham surgery and pregabalin injections; (2) crush injury and pregabalin injections; and (3) crush injury and saline vehicle injections. Nerve regeneration was evaluated with weekly walking tracks and histomorphometry. There were no significant differences in sciatic function index or histomorphometric parameters at the 21-day endpoint between the pregabalin-treated rats undergoing crush injury and the saline-treated controls. Although we have observed a subjectively improved clinical course in human patients treated with pregabalin after traumatic nerve injury, the effect does not appear to be due to accelerated nerve regeneration.

Proline-rich polypeptides in Alzheimer's disease and neurodegenerative disorders -- therapeutic potential or a mirage?

The development of effective and safe drugs for a growing Alzheimer disease population is an increasing need at present. Both experimental and clinical evidence support a beneficial effect of proline-rich polypeptides in a number of neurodegenerative diseases, including Alzheimer disease. Experimental data have shown that proline-rich polypeptides isolated from bovine neurohypophisis possess neuroprotective and neuromodulatory properties in mice with aluminum neurotoxicosis or neuronal damage caused by venoms and toxins. Proline-rich polypeptides from ovine colostrums, so called Colostrinin, have been shown to produce cognitive improvement in an experimental model and in patients with Alzheimer disease. However, the precise mechanism underlying the neuroprotective action of proline-rich polypeptides is not very well established. Moreover, studies pointing at a neuroprotective effect of proline-rich polypeptides from bovine neurohypophisis in humans have not been reported thus far. The authors conclude that more detailed information on the mode of action of proline-rich polypeptides is needed as well as confirmation of their efficacy in broad clinical trials before this approach can really show its potential in the treatment of neurodegenerative disorders.