From quail to earthquakes and human conflict: a historical perspective of rhabdomyolysis

Progress in the Diagnostic and Predictive Evaluation of Crush Syndrome

Crush syndrome (CS), also known as traumatic rhabdomyolysis, is a syndrome with a wide clinical spectrum; it is caused by external compression, which often occurs in earthquakes, wars, and traffic accidents, especially in large-scale disasters. Crush syndrome is the second leading cause of death after direct trauma in earthquakes. A series of clinical complications caused by crush syndrome, including hyperkalemia, myoglobinuria, and, in particular, acute kidney injury (AKI), is the main cause of death in crush syndrome. The early diagnosis of crush syndrome, the correct evaluation of its severity, and accurate predictions of a poor prognosis can provide personalized suggestions for rescuers to carry out early treatments and reduce mortality. This review summarizes various methods for the diagnostic and predictive evaluation of crush syndrome, including urine dipstick tests for a large number of victims, traditional and emerging biomarkers, imaging-assisted diagnostic methods, and developed evaluation models, with the aim of providing materials for scholars in this research field.

Mini Review of Biochemical Basis, Diagnosis and Management of Crush Syndrome

Crush syndrome (CS) is a metabolic disorder whose victims are individuals suffered from natural disasters such as earthquake or man-made conflicts. CS complications include acute kidney injury and cardiac arrhythmia that collectively end with death if untreated immediately. These complications are accounted for the liberation of damaged muscle tissues contents, primarily myoglobin and potassium. The present mini review discusses the biochemical basis of the development of CS. In addition, diagnosis and management and the application of novel experimental therapeutics of CS are also highlighted.

Therapeutic propensity of ginsenosides Rg1 and Rg3 in rhabdomyolysis-induced acute kidney injury and renohepatic crosstalk in rats

BACKGROUND

Ginseng is a traditional herbal medicine used for thousands of years in Southeast Asian countries because of its medicinal properties. Ginsenosides Rg1 and Rg3 have demonstrated therapeutic properties against a broad spectrum of diseases.

PURPOSE

Here in this study, we investigated the therapeutic efficacy of Rg1 and Rg3 in alleviating glycerol-induced acute kidney injury, also known as rhabdomyolysis-induced acute kidney injury (RAKI).

METHODS

AKI was induced in male Wistar rats through intramuscular injection of 10 mL/kg glycerol and simultaneous oral treatment of ginsenosides Rg1 and Rg3 for 3 days. We also evaluated the therapeutic potential of Rg1 and Rg3 on human embryonic kidney epithelial (HEK-293). Cell viability and LDH assay were performed on HEK-293 cells to evaluate the toxicity of Rg1 and Rg3. Evaluation of important kidney damage markers such as creatinine and blood urea nitrogen (BUN) was carried out at different time points from the rat serum. Histopathological analysis was performed on kidney tissues. We also performed experiments such as ELISA assay, immunohistochemistry, immunofluorescence staining, COMET assay, western blotting, TUNEL assay, and flow cytometry to obtain results.

RESULTS

Rg1 and Rg3 significantly downregulated the expression of kidney damage markers such as creatinine and BUN in a dose-dependent manner. Histopathological analysis revealed damage across the glomerulus, tubules, and collecting duct rendering the kidney dysfunctional in glycerol treatment groups. However, Rg1 and Rg3 treated groups showed a significant reduction in tubular necrosis at both 10 and 20 mg/kg. There was also a sharp downregulation of oxidative and ER stress markers. Additionally, we observed nuclear translocation of Nrf2 which were more prominent in kidney tissues. Rg1 and Rg3 were also able to mitigate apoptotic cell death in vitro and in vivo evaluated through immunofluorescence staining for p53, TUNEL assay, flow cytometry, and immunoblotting for intrinsic apoptosis markers.

CONCLUSION

In summary, we conclude that Rg1 and Rg3 exhibited natural therapeutic remedy against AKI.

Rhabdomyolysis Caused by Hypothyroidism: Research Progress

Rhabdomyolysis (RM) refers to the clinical syndrome caused by the release of intracellular substances into the extracellular fluid and blood circulation after rhabdomyocyte destruction due to various etiologies. In severe cases, RM can lead to life-threatening conditions such as acute kidney injury. Hypothyroidism is a rare cause of RM that can lead to missed diagnosis or misdiagnosis, and the condition worsens in the absence of timely and effective treatment. Herein, reported cases of RM caused by hypothyroidism are summarized, and clinical diagnosis and treatment recommendations are proposed to facilitate early identification and treatment of the disease.

Recent advances in our understanding of genetic rhabdomyolysis

PURPOSE OF REVIEW

This review summarizes recent advances in our understanding of the genetics of rhabdomyolysis.

RECENT FINDINGS

Rhabdomyolysis is the acute breakdown of myofibres resulting in systemic changes that can be life-threatening. Environmental triggers, including trauma, exercise, toxins and infections, and/or gene defects can precipitate rhabdomyolysis. A schema (aptly titled RHABDO) has been suggested for evaluating whether a patient with rhabdomyolysis is likely to harbour an underlying genetic defect. It is becoming increasingly recognized that defects in muscular dystrophy and myopathy genes can trigger rhabdomyolysis, even as the sole or presenting feature. Variants in genes not previously associated with human disease have been identified recently as causative of rhabdomyolysis, MLIP , MYH1 and OBSCN . Our understanding of the pathomechanisms contributing to rhabdomyolysis have also improved with an increased awareness of the role of mitochondrial dysfunction in LPIN1 , FDX2 , ISCU and TANGO2 -mediated disease.

SUMMARY

An accurate genetic diagnosis is important for optimal clinical management of the patient, avoiding associated triggers and genetic counselling and cascade screening. Despite recent advances in our understanding of the genetics contributing to rhabdomyolysis, many patients remain without an accurate genetic diagnosis, suggesting there are many more causative genes, variants and disease mechanisms to uncover.

Functional consequence of myeloid ferritin heavy chain on acute and chronic effects of rhabdomyolysis-induced kidney injury

Acute kidney injury (AKI) is a serious complication of rhabdomyolysis that significantly impacts survival. Myoglobin released from the damaged muscle accumulates in the kidney, causing heme iron-mediated oxidative stress, tubular cell death, and inflammation. In response to injury, myeloid cells, specifically neutrophils and macrophages, infiltrate the kidneys, and mediate response to injury. Ferritin, comprised of ferritin light chain and ferritin heavy chain (FtH), is vital for intracellular iron handling. Given the dominant role of macrophages and heme-iron burden in the pathogenesis of rhabdomyolysis, we studied the functional role of myeloid FtH in rhabdomyolysis-induced AKI and subsequent fibrosis. Using two models of rhabdomyolysis induced AKI, we found that during the acute phase, myeloid FtH deletion did not impact rhabdomyolysis-induced kidney injury, cell death or cell proliferation, suggesting that tubular heme burden is the dominant injury mechanism. We also determined that, while the kidney architecture was markedly improved after 28 days, tubular casts persisted in the kidneys, suggesting sustained damage or incomplete recovery. We further showed that rhabdomyolysis resulted in an abundance of disparate intra-renal immune cell populations, such that myeloid populations dominated during the acute phase and lymphoid populations dominated in the chronic phase. Fibrotic remodeling was induced in both genotypes at 7 days post-injury but continued to progress only in wild-type mice. This was accompanied by an increase in expression of pro-fibrogenic and immunomodulatory proteins, such as transforming growth factor-β, S100A8, and tumor necrosis factor-α. Taken together, we found that while the initial injury response to heme burden was similar, myeloid FtH deficiency was associated with lesser interstitial fibrosis. Future studies are warranted to determine whether this differential fibrotic remodeling will render these animals more susceptible to a second AKI insult or progress to chronic kidney disease at an accelerated pace.

Ulinastatin Alleviates Rhabdomyolysis-Induced Acute Kidney Injury by Suppressing Inflammation and Apoptosis via Inhibiting TLR4/NF-κB Signaling Pathway

Acute kidney injury (AKI) is an important complication of rhabdomyolysis (RM), but there is lack of effective treatments. Ulinastatin (UTI) is a broad-spectrum serine protease inhibitor isolated and purified from human urine with strong anti-inflammatory and cytoprotective actions. The aim of this research was to investigate the effect and potential mechanism of UTI on RM-induced AKI (RM-AKI). We established RM-induced AKI model and myoglobin (Mb)-stimulated NRK-52E cell model. In vivo, twenty-four rats were randomly divided into three groups (n = 8): control, RM-AKI, and RM-AKI + UTI. In vitro, the NRK-52E cells were divided into six groups according to the different treatment method. Mb-stimulated NRK-52E cells were treated with UTI or si-TLR4 transfection to characterize the mechanisms of UTI in RM-AKI. Indicators of the kidney injury, cell viability, cell cycle, oxidative stress, inflammation, apoptosis, and TLR4/NF-κB signaling pathway were assessed. In vivo and in vitro, UTI significantly decreased the expression of TLR4 and p65. In vivo, UTI significantly improved renal function and reduced inflammatory reaction and kidney injury. In vitro, UTI protected NRK-52E cells from Mb stimulation by suppressing cell cytotoxicity, cell cycle inhibition, overproduction of ROS, inflammation, and apoptosis. Additionally, UTI played a protective role by downregulating the TLR4 expression. The results indicate that UTI alleviates RM-AKI by suppressing the inflammatory response and apoptosis via inhibiting TLR4/NF-κB signaling pathway. Our study provides a new mechanism for the protective effect of UTI on RM-AKI.

Bi-allelic loss-of-function OBSCN variants predispose individuals to severe recurrent rhabdomyolysis

Rhabdomyolysis is the acute breakdown of skeletal myofibres in response to an initiating factor, most commonly toxins and over exertion. A variety of genetic disorders predispose to rhabdomyolysis through different pathogenic mechanisms, particularly in patients with recurrent episodes. However, most cases remain without a genetic diagnosis. Here we present six patients who presented with severe and recurrent rhabdomyolysis, usually with onset in the teenage years; other features included a history of myalgia and muscle cramps. We identified ten bi-allelic loss-of-function variants in the gene encoding obscurin (OBSCN) predisposing individuals to recurrent rhabdomyolysis. We show reduced expression of OBSCN and loss of obscurin protein in patient muscle. Obscurin is proposed to be involved in SR function and Ca2+ handling. Patient cultured myoblasts appear more susceptible to starvation as evidenced by a greater decreased in SR Ca2+ content compared to control myoblasts. This likely reflects a lower efficiency when pumping Ca2+ back into the SR and/or a decrease in Ca2+ SR storage ability when metabolism is diminished. OSBCN variants have previously been associated with cardiomyopathies. None of the patients presented with a cardiomyopathy and cardiac examinations were normal in all cases in which cardiac function was assessed. There was also no history of cardiomyopathy in first degree relatives, in particular in any of the carrier parents. This cohort is relatively young, thus follow-up studies and the identification of additional cases with bi-allelic null OBSCN variants will further delineate OBSCN-related disease and the clinical course of disease.

Heme Burden and Ensuing Mechanisms That Protect the Kidney: Insights from Bench and Bedside

With iron at its core, the tetrapyrrole heme ring is a cardinal prosthetic group made up of many proteins that participate in a wide array of cellular functions and metabolism. Once released, due to its pro-oxidant properties, free heme in sufficient amounts can result in injurious effects to the kidney and other organs. Heme oxygenase-1 (HO-1) has evolved to promptly attend to such injurious potential by facilitating degradation of heme into equimolar amounts of carbon monoxide, iron, and biliverdin. HO-1 induction is a beneficial response to tissue injury in diverse animal models of diseases, including those that affect the kidney. These protective attributes are mainly due to: (i) prompt degradation of heme leading to restraining potential hazardous effects of free heme, and (ii) generation of byproducts that along with induction of ferritin have proven beneficial in a number of pathological conditions. This review will focus on describing clinical aspects of some of the conditions with the unifying end-result of increased heme burden and will discuss the molecular mechanisms that ensue to protect the kidneys.

Mild-to-severe poisoning due to Conium maculatum as toxic herb: A case series

Conium maculatum toxicity may occur by mistakenly or intentionally eating this plant. Due to muscarinic or nicotinic symptoms associated with this plant toxicity, supportive care and treatment with atropine are urgently important.

Acute Kidney Injury is Aggravated in Aged Mice by the Exacerbation of Proinflammatory Processes

Acute kidney injury (AKI) is more frequent in elderly patients. Mechanisms contributing to AKI (tubular cell death, inflammatory cell infiltration, impaired mitochondrial function, and prolonged cell-cycle arrest) have been linked to cellular senescence, a process implicated in regeneration failure and progression to fibrosis. However, the molecular and pathological basis of the age-related increase in AKI incidence is not completely understood. To explore these mechanisms, experimental AKI was induced by folic acid (FA) administration in young (3-months-old) and old (1-year-old) mice, and kidneys were evaluated in the early phase of AKI, at 48 h. Tubular damage score, KIM-1 expression, the recruitment of infiltrating immune cells (mainly neutrophils and macrophages) and proinflammatory gene expression were higher in AKI kidneys of old than of young mice. Tubular cell death in FA-AKI involves several pathways, such as regulated necrosis and apoptosis. Ferroptosis and necroptosis cell-death pathways were upregulated in old AKI kidneys. In contrast, caspase-3 activation was only found in young but not in old mice. Moreover, the antiapoptotic factor BCL-xL was significantly overexpressed in old, injured kidneys, suggesting an age-related apoptosis suppression. AKI kidneys displayed evidence of cellular senescence, such as increased levels of cyclin dependent kinase inhibitors p16ink4a and p21cip1, and of the DNA damage response marker γH2AX. Furthermore, p21cip1 mRNA expression and nuclear staining for p21cip1 and γH2AX were higher in old than in young FA-AKI mice, as well as the expression of senescence-associated secretory phenotype (SASP) components (Il-6, Tgfb1, Ctgf, and Serpine1). Interestingly, some infiltrating immune cells were p21 or γH2AX positive, suggesting that molecular senescence in the immune cells (“immunosenescence”) are involved in the increased severity of AKI in old mice. In contrast, expression of renal protective factors was dramatically downregulated in old AKI mice, including the antiaging factor Klotho and the mitochondrial biogenesis driver PGC-1α. In conclusion, aging resulted in more severe AKI after the exposure to toxic compounds. This increased toxicity may be related to magnification of proinflammatory-related pathways in older mice, including a switch to a proinflammatory cell death (necroptosis) instead of apoptosis, and overactivation of cellular senescence of resident renal cells and infiltrating inflammatory cells.