High resolution respirometry in freshly isolated peripheral blood mononuclear cells as a diagnostic method for malignant hyperthermia predisposition -A pilot study

Abstract

Introduction Malignant hyperthermia (MH) is a potential life-threatening reaction displayed by susceptible patients under general anaesthesia upon encounter with volatile halogenated anaesthetics and succinylcholine. Background Biochemically, the development of MH is based upon an abnormal activation of ryanodine receptors in the sarcoplasmic reticulum. Clinically, MH presents with severe signs of hyper catabolism, fever, rigid muscles, respiratory acidosis, metabolic acidosis, tachypnoea, tachycardia, rhabdomyolysis and electrolyte imbalance. The estimated incidence of MH for children and adults undergoing surgery are, respectively, 1:15 000 and 1:50 000 in North American and European populations, although, more recent studies have demonstrated that the incidence of carried MH-trait might be close to 1:2000. To date, diagnostics of MH carrier state still relies on an invasive muscle biopsy ex vivo test, warranting the development of a less invasive modality. Material and method In this study we have tested whether oxygen consumption by peripheral blood mononuclear cells (PMBCs) exposed to the potent pharmacological opener of Ca channels could be a feasible readout for a diagnostic test for a possible susceptibility of patients to MH development. PBMCs were isolated using standard protocol and oxygen consumption rates were assessed with they use of an oxygraph. Linear regression was used to assess the rate of oxygen consumption and Wilcoxon signed-rank test was performed to compare the pairwise slopes. Results All calculated values using linear regression were significant by a large margin and the R2 adjusted values was high for all calculated models. Wilcoxon signed-rank test was only significant for three of the 16 pairwise compared experiments and all of them were in discordance with their respective repeated experiments. Conclusion This thesis has not provided enough evidence to assume a difference in oxygen consumption rate between PBMCs exposed to the potent RyR activator 4-CMC, and resting PBMCs.