Investigating the Clinical Value of Novel Kidney Injury Inflammatory Biomarkers in Snakebite Victims

Objective: The expression of vascular endothelial growth factor-A (VEGF-A) in snakebite patients, its value in patient prognosis and the correlation of VEGF-A with renal function were analysed. Methods: A total of 124 snakebite patients admitted from January 2019 to January 2021 were retrospectively analysed and included in the observation group, and 40 healthy individuals who underwent physical examination in the same hospital within the same period were included in the control group. The t-test was used in analysing differences between the serum VEGF-A levels of the observation and control groups and changes in VEGF-A and renal function indices before and after treatment in the observation group. The effects of treatment on each patient in the observation group were evaluated, and the patients were divided into improved and unimproved groups according to the post-treatment condition. The predictive value of VEGF-A and renal function indices in patients in the improved and unimproved groups and their efficacy for snakebite patients were analysed through receiver operating characteristic (ROC) analysis. Finally, correlation analysis was used in evaluating the correlation between VEGF-A and renal function indices. Results: VEGF-A was significantly higher in patients in the observation group (339.66 ± 97.72 pg/mL) than in patients in the control group (52.41 ± 8.93 pg/mL; p < 0.001). VEGF-A and renal function indices in the serum of patients were significantly lower after treatment than those before treatment (p < 0.0001). According to efficacy, the patients were divided into improved group (n = 102) and unimproved group (n = 22). The pre-treatment VEGF-A levels were significantly lower in patients in the improved group (318.47 ± 90.80 pg/mL) than in patients in the unimproved group (437.88 ± 63.16 pg/mL; p < 0.001) (AU)

Sirt2 positively regulates muscle regeneration after Notexin-induced muscle injury.

Sirt2 regulates various biological processes by deacetylating target genes. Despite roles in regulating proliferation, cell cycle, and glucose metabolism, which are closely associated with skeletal muscle physiology, Sirt2 functions in this tissue remain unclear. In this study, genetic deletion of Sirt2 delayed muscle regeneration after Notexin-induced muscle injury. Gene expressions of myogenic regulatory factors, including Myf5, MyoD, and Myogenin, and cell cycle regulators, such as cyclin D1 and CDK2, were repressed in Sirt2 knockout mice after injury. Also, Sirt2 knockout mice presented muscle atrophy after muscle injury which is associated with the down-regulation of anabolic signaling and the up-regulation of catabolic signaling, in particular, increased atrogin1 transcriptional expression. Thus, Sirt2 positively regulated skeletal muscle regeneration after muscle injury by regulating transcriptional expression involved in myogenesis, cell cycle, and anabolic and catabolic signaling. Based on the in vivo analyses, Sirt2 could function as an interventional therapeutic for chronic myopathy, which is characterized by impaired muscle regeneration and muscle atrophy.

Pretreatment with atorvastatin ameliorates cobra venom factor-induced acute lung inflammation in mice.

BACKGROUND: The complement system plays a critical role as the pathogenic factor in the models of acute lung injury due to various causes. Cobra venom factor (CVF) is a commonly used complement research tool. The CVF can cause acute inflammation in the lung by producing complement activation components. Atorvastatin (ATR) is a 3-hydroxy-3-methylglutaryl coenzyme A inhibitor approved for control of plasma cholesterol levels. This inhibitor can reduce the acute pulmonary inflammatory response. However, the ability of ATR in treating acute lung inflammation caused by complement activation is still unknown. Therefore, we investigated the effect of ATR on lung inflammation in mice induced by activation of the complement alternative pathway in this study. METHODS: ATR (10 mg/kg/day via oral gavage) was administered for 7 days before tail vein injection of CVF (25 µg/kg). On the seventh day, all mice were sacrificed 1 h after injection. The lung lobe, bronchoalveolar lavage fluid (BALF), and blood samples were collected. The myeloperoxidase (MPO) activity of the lung homogenate, the leukocyte cell count, and the protein content of BALF were measured. The levels of interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), P-selectin, and Intercellular cell adhesion molecule-1 (ICAM-1) in BALF and serum were determined by enzyme-linked immunosorbent assay. The pathological change of the lung tissue was observed by hematoxylin and eosin staining. The deposition of C5b-9 in the lung tissue was detected by immunohistochemistry. The phosphorylation of NF-κB p65 in the lung tissues was examined by immunohistochemistry and western blotting. RESULTS: The lung inflammation levels were determined by measuring the leukocyte cell numbers and protein content of BALF, the lung MPO activity, and expression and staining of the inflammatory mediators (IL-6 and TNF-α), and adhesion molecules (P-selectin and ICAM-1) for lung lesion. A significant reduction in the lung inflammation levels was observed after 7 days in ATR pre-treated mice with a CVF-induced lung disease. Deposition of C5b-9 was significantly alleviated by ATR pretreatment. Early intervention with ATR significantly reduced the development of acute lung inflammation on the basis of phosphorylation of NF-κB p65 in the lung. CONCLUSION: These findings suggest the identification of ATR treatment for the lung inflammation induced by activating the complement system on the basis of its anti-inflammatory response. Together with the model replicating the complement activating characteristics of acute lung injury, the results may be translatable to the overactivated complement relevant diseases.

Effects of Mlx-8, a phospholipase A2 from Brazilian coralsnake Micrurus lemniscatus venom, on muscarinic acetylcholine receptors in rat hippocampus

Here, we described the presence of a neurotoxin with phospholipase A2 activity isolated from Micrurus lemniscatus venom (Mlx-8) with affinity for muscarinic acetylcholine receptors (mAChRs). Methods: The purification, molecular mass determination, partial amino acid sequencing, phospholipase A2 activity determination, inhibition of the binding of the selective muscarinic ligand [3H]QNB and inhibition of the total [3H]inositol phosphate accumulation in rat hippocampus of the Mlx-8 were determined. Results: Thirty-one fractions were collected from HPLC chromatography, and the Mlx-8 toxin was used in this work. The molecular mass of Mlx-8 is 13.628 Da. Edman degradation yielded the following sequence: NLYQFKNMIQCTNTRSWL-DFADYG-CYCGRGGSGT. The Mlx-8 had phospholipase A2 enzymatic activity. The pKi values were determined for Mlx-8 toxin and the M1 selective muscarinic antagonist pirenzepine in hippocampus membranes via [3H]QNB competition binding assays. The pKi values obtained from the analysis of Mlx-8 and pirenzepine displacement curves were 7.32 ± 0.15, n = 4 and 5.84 ± 0.18, n = 4, respectively. These results indicate that Mlx-8 has affinity for mAChRs. There was no effect on the inhibition ability of the [3H]QNB binding in hippocampus membranes when 1 µM Mlx-8 was incubated with 200 µM DEDA, an inhibitor of phospholipase A2. This suggests that the inhibition of the phospholipase A2 activity of the venom did not alter its ability to bind to displace [3H]QNB binding. In addition, the Mlx-8 toxin caused a blockade of 43.31 ± 8.86%, n = 3 and 97.42 ± 2.02%, n = 3 for 0.1 and 1 µM Mlx-8, respectively, on the total [3H]inositol phosphate content induced by 10 µM carbachol. This suggests that Mlx-8 inhibits the intracellular signaling pathway linked to activation of mAChRs in hippocampus. Conclusion: The results of the present work show, for the first time, that muscarinic receptors are also affected by the Mlx-8 toxin, a muscarinic ligand with phospholipase A2 characteristics, obtained from the venom of the Elapidae snake Micrurus lemniscatus, since this toxin was able to compete with muscarinic ligand [3H]QNB in hippocampus of rats. In addition, Mlx-8 also blocked the accumulation of total [3H]inositol phosphate induced by muscarinic agonist carbachol. Thus, Mlx-8 may be a new pharmacological tool for examining muscarinic cholinergic function.(AU)

Naja atra snakebite in Taiwan.

BACKGROUND: Naja atra snakebite is uncommon in Taiwan and causes distinct effects on its victims. Although the Taiwan government produces its own specific antivenom, little information on the management of N. atra snakebite is available. MATERIALS AND METHODS: We retrospectively evaluated 183 patients admitted to two medical centers. Of these, 45 were identified as definite cases of N. atra snakebite, 86 as suspected cases, and 52 as clinical cases. Demographic data, symptomatology, and management were compared between these case groups. RESULTS: Symptomatology and management were similar in the three groups. Among the 183 patients, 10 (5.5%) were asymptomatic and nine (4.9%) had transient and partial ptosis or body weakness. The principal effects were local tissue swelling and pain in 173 patients (94.5%), followed by clinically suspected wound infection in 148 (80.9%), skin necrosis in 120 (65.6%), necrotizing soft tissue infection in 77 (42.1%), fever in 59 (32.2%), and gastrointestinal effects in 53 (29%). The median total dose of specific antivenom needed to treat N. atra envenoming was 10 vials. In the envenomed patients, debridement was required in 74 patients (42.8%), fasciotomy/fasciectomy in 46 (26.6%), and finger or toe amputation in seven (4%). The first operation was performed at a median of 3.5 days after the bite. DISCUSSION AND CONCLUSIONS: Based on these typical manifestations, clinical diagnosis of N. atra snakebites may be feasible and practical. In contrast to other snakes of Elapidae family, N. atra bite did not cause serious neurological effects. Early surgical consultation should be obtained because half of the patients underwent surgery due to infectious complications. Acute compartment syndrome was the surgical indication in rare cases; however, overestimation of the incidence may have occurred. This syndrome should be confirmed by serial intracompartmental pressure monitoring instead of only physical examination, and a sufficient dose of antivenom should be given prior to surgical decompression.

Inducing and Evaluating Skeletal Muscle Injury by Notexin and Barium Chloride.

Models of skeletal muscle injury in animal models are invaluable tools to assess muscle stem cell (MuSC)-mediated tissue repair. The optimization and comprehensive evaluation of these approaches have greatly improved our ability to assess MuSC regenerative potential. Here we describe the procedures for skeletal muscle injury with notexin and BaCl2 and assessment of the dynamics of tissue regeneration.

An eleven year old boy with pain abdomen and early morning neuroparalytic syndrome.

An 11 year old boy presented with pain abdomen and tenderness all over body when he got up from sleep early in the morning and subsequently had one vomiting after 30 min. He had no other significant past medical history. The child was shifted to nearby health facility where he was managed as a case of acute abdomen on the basis of suggestive history and clinical findings. Within 2 h after the onset of clinical features suggestive of acute abdomen the patient went on to develop marked ptosis and flaccid quadriplegia. The young boy underwent a sequence of clinical tests which were noncontributory. Based on the clinical picture, a differential diagnosis of hypokalemic paralysis, botulism, Miller Fischer syndrome and EMNS were considered. Through exclusion, the most probable diagnosis for the symptoms was elapid envenomation hence he was started on anti-snake venom (ASV) with working diagnosis of EMNS. Within 2 h, he began to show improvement. This recovery with ASV suggests the possibility of elapid envenomation.

Coastal taipan (Oxyuranus scutellatus) envenomation of a dog.

CASE REPORT: An 8-year-old mixed-breed dog was envenomed by a juvenile coastal taipan (Oxyuranus scutellatus). The dog presented initially with coagulopathy and weakness, then developed neuromuscular paralysis and respiratory failure. Progressive myopathy peaked 3 days following admission. Taipan antivenom administration, mechanical ventilation therapy and supportive patient care resulted in complete recovery. Symptoms of neuropathy began to resolve 3 days following envenomation, with the dog discharged 6 days following envenomation. CONCLUSION: To the author's knowledge, this is the first reported case of coastal taipan envenomation of a dog.

Intracranial haemorrhages associated with venom induced consumption coagulopathy in Australian snakebites (ASP-21).

Intracranial haemorrhage (ICH) is a rare life-threatening consequence of venom induced consumption coagulopathy in snake-bite. It is unclear why certain patients haemorrhage. We aimed to investigate ICH in snake envenoming. Cases of venom-induced consumption coagulopathy from July 2005-June 2014 were identified from the Australian Snakebite Project, a prospective multicentre cohort of snake-bites. Cases with venom-induced consumption coagulopathy were extracted with data on the snake-bite, clinical effects, laboratory investigations, treatment and outcomes. 552 cases had venom-induced consumption coagulopathy; median age, 40 y (2-87 y), 417 (76%) males, 253 (46%) from brown snakes and 17 died (3%). There were 6/552 (1%) cases of ICH; median age, 71 y (59-80 y), three males and five from brown snakes. All received antivenom and five died. All six had a history of hypertension. Time to onset of clinical effects consistent with ICH was 8-12 h in four cases, and within 3 h in two. Difficult to manage hypertension and vomiting were common. One patient had a normal cerebral CT on presentation and after the onset of focal neurological effects a repeat CT showed an ICH. ICH is rare in snake-bite with only 1% of patients with coagulopathy developing one. Older age and hypertension were associated with ICH.

Disruption of muscle renin-angiotensin system in AT1a-/- mice enhances muscle function despite reducing muscle mass but compromises repair after injury.

The role of the renin-angiotensin system (RAS) in vasoregulation is well established, but a localized RAS exists in multiple tissues and exerts diverse functions including autonomic control and thermogenesis. The role of the RAS in the maintenance and function of skeletal muscle is not well understood, especially the role of angiotensin peptides, which appear to contribute to muscle atrophy. We tested the hypothesis that mice lacking the angiotensin type 1A receptor (AT(1A)(-/-)) would exhibit enhanced whole body and skeletal muscle function and improved regeneration after severe injury. Despite 18- to 20-wk-old AT(1A)(-/-) mice exhibiting reduced muscle mass compared with controls (P < 0.05), the tibialis anterior (TA) muscles produced a 25% higher maximum specific (normalized) force (P < 0.05). Average fiber cross-sectional area (CSA) and fiber oxidative capacity was not different between groups, but TA muscles from AT(1A)(-/-) mice had a reduced number of muscle fibers as well as a higher proportion of type IIx/b fibers and a lower proportion of type IIa fibers (P < 0.05). Measures of whole body function (grip strength, rotarod performance, locomotor activity) were all improved in AT(1A)(-/-) mice (P < 0.05). Surprisingly, the recovery of muscle mass and fiber CSA following myotoxic injury was impaired in AT(1A)(-/-) mice, in part by impaired myoblast fusion, prolonged collagen infiltration and inflammation, and delayed expression of myogenic regulatory factors. The findings support the therapeutic potential of RAS inhibition for enhancing whole body and skeletal muscle function, but they also reveal the importance of RAS signaling in the maintenance of muscle mass and for normal fiber repair after injury.

CD34 promotes satellite cell motility and entry into proliferation to facilitate efficient skeletal muscle regeneration.

Expression of the cell surface sialomucin CD34 is common to many adult stem cell types, including muscle satellite cells. However, no clear stem cell or regeneration-related phenotype has ever been reported in mice lacking CD34, and its function on these cells remains poorly understood. Here, we assess the functional role of CD34 on satellite cell-mediated muscle regeneration. We show that Cd34(-/-) mice, which have no obvious developmental phenotype, display a defect in muscle regeneration when challenged with either acute or chronic muscle injury. This regenerative defect is caused by impaired entry into proliferation and delayed myogenic progression. Consistent with the reported antiadhesive function of CD34, knockout satellite cells also show decreased motility along their host myofiber. Altogether, our results identify a role for CD34 in the poorly understood early steps of satellite cell activation and provide the first evidence that beyond being a stem cell marker, CD34 may play an important function in modulating stem cell activity.

Alternative splicing dysregulation secondary to skeletal muscle regeneration.

OBJECTIVE: Dysregulation of alternative splicing has become a molecular hallmark of myotonic dystrophy type 1 (DM1), in which neonatal splice variants are expressed in adult skeletal muscle. Splicing dysregulation is induced by RNA containing expanded CUG repeats expressed from the expanded mutant allele by sequestration of muscleblindlike 1 (MBNL1) protein within nuclear RNA foci and increased CUGBP, ELAV-like family member 1 (CELF1) protein levels. Dysregulated splicing has also been identified in other neuromuscular disorders, suggesting either that diseases with different molecular causes share a common pathogenic mechanism or that dysregulated splicing can also be a common secondary consequence of muscle degeneration and regeneration. METHODS: In this study, we examined regulation of alternative splicing in 4 different mouse models of muscular dystrophy, including DM1, limb-girdle muscular dystrophy, congenital merosin-deficient muscular dystrophy, and Duchenne muscular dystrophy, and 2 myotoxin (cardiotoxin and notexin) muscle injury models. RESULTS: We show that DM1-like alternative splicing dysregulation and altered expression of MBNL1 and CELF1 occur in non-DM1 mouse models of muscular dystrophy and muscle injury, most likely due to recapitulation of neonatal splicing patterns in regenerating fibers. In contrast, CELF1 was elevated in nuclei of mature myofibers of the DM1 model, consistent with a primary effect of pathogenic RNA expression. INTERPRETATION: Splicing dysregulation in DM1 is a primary effect of RNA containing expanded CUG repeats. However, we conclude that splicing changes can also be observed secondary to muscle regeneration, and this possibility must be taken into account when evaluating cause-effect relationships between dysregulated splicing and disease processes.

Ocular toxicity associated with indirect exposure to African spitting cobra venom.

Direct ocular inoculation with African spitting cobra (Naja nigricollis) venom in the United States is uncommon, especially in an urban setting, but can lead to serious acute and chronic ocular injury depending on the extent of exposure. We report 2 cases of indirect ocular inoculation with venom from an African spitting cobra, manifesting as periocular soft tissue swelling, extensive conjunctivitis, and corneal epithelial erosion. Both of the reported cases involve young male patients who received prompt emergency evaluation and treatment including copious irrigation of the ocular surface, followed by close monitoring by an ophthalmologist resulting in excellent outcomes with minimal visually significant ocular sequelae.

[Spitting cobras: description of 2 cases in Djibouti]. / Cobras cracheurs: 2 observations à Djibouti.

The purpose of this report is to describe two cases involving ophthalmic exposure to venom from spitting cobras. Based on these cases, readers are reminded that eye injury can be prevented by low-cost treatment consisting of prompt, prolonged saline irrigation. This treatment also reduces pain.

CD-NP, a chimeric natriuretic peptide for the treatment of heart failure.

In development by Nile Therapeutics Inc, under license from the Mayo Foundation, CD-NP is a chimeric natriuretic peptide in which the 15-amino acid C-terminal tail of Dendroaspis natriuretic peptide is fused to the 22-amino acid human C-type natriuretic peptide. The rationale for its design was to create a peptide with the beneficial cardiovascular and renal effects of native natriuretic peptides, but without a clinically significant hypotensive response. CD-NP is able to bind to all three natriuretic peptide receptors (NPR-A, NPR-B and NPR-C) and, therefore, is unique in being able to increase cyclic guanosine monophosphate production downstream of both NPR-A and NPR-B. Animal studies and human trials demonstrated that CD-NP is safe and improves cardiovascular and renal function without inducing significant levels of hypotension. Preliminary data also suggest improved renal function in human heart failure patients. Ongoing clinical trials are needed to further validate CD-NP as an effective treatment option for heart failure.

Pharmacodynamics of a novel designer natriuretic peptide, CD-NP, in a first-in-human clinical trial in healthy subjects.

CD-NP is a novel chimeric natriuretic peptide (NP) consisting of the 22-amino-acid (AA) human C-type natriuretic peptide (CNP), a venodilating peptide with limited renal actions and minimal effects on blood pressure, and the 15-AA C-terminus of Dendroaspis NP (DNP). The rationale for the design of CD-NP was to enhance the renal actions of CNP, the ligand for natriuretic peptide receptor-B, but without inducing excessive hypotension. Here we report the first-in-human studies for CD-NP, which represent the first successful clinical testing of a chimeric NP demonstrating in normal human volunteers that CD-NP possesses cyclic guanosine monophosphate-activating, natriuretic, and aldosterone-suppressing properties without inducing excessive hypotension, laying the foundation for additional studies on this first-in-class new cardiovascular therapeutic in human heart failure, which are now underway worldwide.

Extradural haematoma secondary to brown snake (Pseudonaja species) envenomation.

A 4-year-old Siberian Husky dog was treated with brown snake antivenom by his regular veterinarian after a witnessed episode of brown snake envenomation. The dog was discharged 5 hours post presentation despite an ongoing coagulopathy. The dog was presented to the emergency centre 2 hours later because the owner believed the dog to be in pain. Initial examination revealed an ambulatory but neurologically normal patient with thoracolumbar pain and laboratory evidence of a coagulopathy. Despite correction of the coagulopathy, the signs progressed to bilateral hind limb paresis after approximately 3 hours of hospitalisation, and continued to deteriorate over the next 56 hours to loss of deep pain perception in the right hind limb. Computed tomography imaging identified the presence of an extradural haematoma which was subsequently removed via a hemilaminectomy. Surgical decompression was successful in treating the spinal compression and the dog recovered with minimal complications. To our knowledge this is the first report of extradural haematoma secondary to coagulopathy induced by brown snake envenomation.

Elapid snake envenomation in dogs in New South Wales: a review.

Elapid snake envenomation in dogs is a commonly occurring yet poorly described clinical entity. Twelve species of dangerously venomous elapid snakes are found in New South Wales that are capable of causing disease in dogs. Geographical distribution of these species varies, as does their venom composition and systemic envenomation syndromes produced in target species. Elapid venom may be divided into the components of prothrombin activating enzymes, lipases and peptidic neurotoxins. Each species of elapid snake may possess venom components that fit any or all of these classifications. The action of these venom components may result in neurotoxic (pre-synaptic and post-synaptic), haemotoxic (red-cell destruction and coagulation disturbance), cardiovascular, myotoxic and secondary nephrotoxic effects. Marked variability may occur in venom composition between and within snake species, resulting in varying toxicity between species and also potentially unreliable clinical syndromes following envenomation. The existence of certain components consistently within the venom of each snake species allows the broad definition of basic pathological processes and clinicopathological changes resulting from snake species-specific envenomation and these are discussed. Diagnosis of snake envenomation is unreliable if based on clinical signs alone and the use of these signs in conjunction with history, physical examination and laboratory investigation, including snake venom detection kits, is recommended. Treatment of systemic envenomation should be undertaken with initial effective first aid and subsequent administration of snake species-specific antivenom.

[Venomous and poisonous animals. III. Elapidae snake envenomation]. / Envenimations et empoisonnements par les animaux venimeux ou vénéneux. III. Envenimations par Elapidae.

Envenomation by Elapidae snakes is less frequent than by Viperidae snakes but represents a true medical emergency due to rapid progression of cobra syndrome. Elapidae venom contains neurotoxins that paralyze striated muscles especially in the thoracic cavity. Respiratory paralysis can occur within a few hours and is preceded by neurological symptoms (local paresthesia and paresis progressing to the cranial nerves). When cobra envenomation is suspected, antivenom administration by the direct venous route must be undertaken as quickly as possible to stop the envenomation process. Artificial ventilation is necessary in case of dyspnea.