Possible Mechanisms of Cardiac Contractile Dysfunction and Electrical Changes in Ammonium Chloride Induced Chronic Metabolic Acidosis in Wistar Rats

Effect of acidosis on adipose-derived stem cell impairment and gene expression

Based on disappointing results of stem cell-based application in clinical trials for patients with critical limb ischemia, we hypothesized that the acidic environment might be the key factor limiting cell survival and function. In the present study, we used microdialysis to determine presence of acidosis and metabolic imbalance in critical ischemia. Moreover, we explored the effect of extracellular acidosis on adipose-derived stem cells (ADSCs) at molecular and transcriptional level. Our data demonstrate that low pH negatively regulates cell proliferation and survival, also, it results in cell cycle arrest, mitochondrial dynamics disorder, DNA damage as well as the impairment of proangiogenic function in a pH-dependent manner. Further transcriptome profiling identified the pivotal signaling pathways and hub genes in response to acidosis. Collectively, these findings provide strong evidences for a critical role of acidosis in ADSCs impairment with ischemic condition and suggest treatments focus on tissue pH balance and acidosis-mediated hub genes may have therapeutic potential in stem cell-based application.

TRAP1 inhibits MIC60 ubiquitination to mitigate the injury of cardiomyocytes and protect mitochondria in extracellular acidosis

Extracellular acidosis-induced mitochondrial damage of cardiomyocytes leads to cardiac dysfunction, but no detailed mechanism or efficient therapeutic target has been reported. Here we found that the protein levels of MIC60 were decreased in H9C2 cells and heart tissues in extracellular acidosis, which caused mitochondrial damage and cardiac dysfunction. Overexpression of MIC60 maintains H9C2 cells viability, increases ATP production and mitochondrial membrane potential, mitigates the disruptions of mitochondrial structure and cardiac injury. Mechanistically, extracellular acidosis excessively promoted MIC60 ubiquitin-dependent degradation. TRAP1 mitigated acidosis-induced mitochondrial impairments and cardiac injury by directly interacting with MIC60 to decrease its ubiquitin-dependent degradation in extracellular acidosis.

Clinical characteristics and outcome of hospitalized children and adolescent patients with type 1 diabetes during the COVID-19 pandemic: data from a single center surveillance study in Egypt

OBJECTIVES

COVID-19 pandemic significantly impacted the diagnosis of type 1 diabetes and its acute complications. Thus, the study aimed to evaluate the characteristics of pediatric patients with type 1 diabetes hospitalized during the first wave of the pandemic and the prevalence of new onset diabetes among patients with evidence of COVID-19 infection.

METHODS

A single-center surveillance study included all patients with diabetes admitted to Children's Hospital, Ain Shams University, in Egypt between May to August 2020. Data were collected to evaluate patients' clinical and laboratory characteristics as well as their outcomes.

RESULTS

Thirty-six patients were admitted during the study period. The mean age was 8.4 ± 3.8 years. Patients presented late to the emergency department with a mean delay of 3.05 ± 1.19 days from onset of symptoms. 34/36 patients presented in diabetic ketoacidosis (DKA), 50% presenting in severe DKA. Almost 81% of the patients were newly diagnosed. During the study period, SARS-CoV-2 PCR was found positive in four patients, COVID Ig M antibodies were positive in another two patients; all were symptomatic requiring ICU admission. Four patients showed a picture suggestive of the multi-inflammatory syndrome (MIS-C); cardiac affection was a constant feature.

CONCLUSIONS

The pandemic affected both the prevalence and severity of DKA among pediatric patients. The increased prevalence of severe DKA could be partly related to delayed hospital admission or the effect of COVID-19 in triggering DKA. Efforts should be done to continuously raise awareness about diabetes in children as well as the importance of seeking timely medical guidance.

miR-126 suppresses neuronal apoptosis in rats after cardiopulmonary resuscitation via regulating p38MAPK

In this study, we aimed to evaluate the effect of microRNA-126 (miR-126) on neuronal apoptosis in cardiopulmonary resuscitation rats and to explore the related molecular mechanism. The expression of miR-126 in brain tissues of rats after cardiopulmonary resuscitation was measured by real-time fluorescence quantitative polymerase chain reaction (RT-qPCR). The basic parameters of cardiopulmonary resuscitation were recorded by miR-126 mimic injection in rats after cardiopulmonary resuscitation. Hematoxylin-eosin staining was used to observe the pathological changes of hippocampus. Immunohistochemistry was used to observe the expression of p38 and caspase-3 protein. Furthermore, the expression of p38 mitogen-activated protein kinase (p38MAPK), Jun N-terminal kinase (JNK), and extracellular signal-regulated kinase 1/2 (ERK1/2) in rat hippocampus was detected by RT-qPCR and Western blot. In order to confirm whether miR-126 takes part in the p38MAPK pathway in the hippocampus of rats after cardiopulmonary resuscitation, the p38MAPK pathway inhibitor (SB203580) and activator (anisomycin) were added. The results showed overexpression of miR-126 could significantly increase the neurological function score and improve the pathological morphology of hippocampus in rats after cardiopulmonary resuscitation. miR-126 overexpression also could reduce the neuronal apoptosis, p38, and caspase-3 expression in the hippocampus. Moreover, the p38MAPK and JNK expression was downregulated and ERK1/2 expression was upregulated after miR-126 mimic injection (p < 0.05). The results of inhibition of p38MAPK pathway were consistent with those of overexpression of miR-126 (p > 0.05). This study indicated miR-126 could significantly reduce neuronal apoptosis of hippocampus in rats after cardiopulmonary resuscitation, which might be involved in the regulation of p38MAPK pathway.

Myocardial dysfunction associated with diabetic ketoacidosis in a 5-year-old girl

In this study, we report a case of a 5-year-old girl with new onset of insulin-dependent diabetes mellitus, who presented with severe diabetic ketoacidosis associated with brain edema and severe myocardial dysfunction, needing intubation and inotropic support. To our knowledge, this is the youngest reported case with severe diabetic ketoacidosis complicated with myocardial dysfunction.

Fresh red blood cells transfusion protects against aluminum phosphide-induced metabolic acidosis and mortality in rats

BACKGROUND

Aluminum phosphide (AlP) is used as pesticide in some countries for protection of stored grains. Human poisoning with AlP due to suicide attempt or accidental environmental exposure is associated with very high mortality partially due to development of severe metabolic acidosis. Previous studies have shown that hemoglobin has high buffering capacity and erythrocytes can potentially be used for management of metabolic acidosis. The aim of this study was to evaluate the effect of fresh packed red blood cells (RBC) transfusion on survival and cardiovascular function in AlP-poisoned rats.

METHODOLOGY/PRINCIPAL FINDINGS

Rats were poisoned with AlP by gavage. Fresh packed RBC was transfused via tail vein after AlP administration. Acid-base balance, vital signs and mortality was assessed and compared in experimental groups. Infusion of fresh packed RBC (1.5 ml) one hour after AlP (4-15 mg/kg) intoxication was associated with a significant decrease in mortality rate. Packed RBC infusion improved blood pH, HCO3-, Na+ and Ca2+ levels. Plasma troponin level was also reduced and ECG changes were reversed following packed RBC infusion in AlP intoxicated rats.

CONCLUSIONS

Our results showed that fresh RBC transfusion could ameliorate metabolic acidosis and enhance survival in AlP-poisoned rat. We assume that an increase in pool of RBCs may modulate acid-base balance or potentially chelate AlP-related toxic intermediates via phosphine-hemoglobin interaction.