Relation of Low Serum Magnesium to Mortality and Cardiac Allograft Vasculopathy Following Heart Transplantation.

Hypomagnesemia is commonly observed in heart transplant (HT) recipients receiving calcineurin inhibitors. Since low serum magnesium (s-Mg) has been implicated in the progression of atherosclerosis, potentially leading to worsening coronary heart disease, arrhythmias and sudden death, we investigated the association between s-Mg and HT outcomes. Between 2002 and 2017, 150 HT patients assessed for s-Mg were divided into high (≥1.7 mg/dL) and low s-Mg groups according to the median value of all s-Mg levels recorded during the first 3 months post-HT. Endpoints included survival, cardiac allograft vasculopathy (CAV), any-treated rejection (ATR) and NF-MACE. Kaplan-Meier analysis showed that at 15 years after HT, both survival (76 vs 33%, log-rank p = 0.007) and freedom from CAV (75 vs 48%, log-rank p = 0.01) were higher in the high versus low s-Mg group. There were no significant differences in freedom from NF-MACE or ATR. Multivariate analyses consistently demonstrated that low s-Mg was independently associated with a significant 2.6-fold increased risk of mortality and 4-fold increased risk of CAV (95%CI 1.06 to 6.4, p = 0.04; 95%CI 1.12 to 14.42, p = 0.01, respectively). In conclusion, low s-Mg is independently associated with increased mortality and CAV in HT patients. Larger multi-center prospective studies are needed to confirm these findings and to examine the effect of Mg supplementation.

Genetic modification of the diarrhoeal pathogen Cryptosporidium parvum.

Recent studies into the global causes of severe diarrhoea in young children have identified the protozoan parasite Cryptosporidium as the second most important diarrhoeal pathogen after rotavirus. Diarrhoeal disease is estimated to be responsible for 10.5% of overall child mortality. Cryptosporidium is also an opportunistic pathogen in the contexts of human immunodeficiency virus (HIV)-caused AIDS and organ transplantation. There is no vaccine and only a single approved drug that provides no benefit for those in gravest danger: malnourished children and immunocompromised patients. Cryptosporidiosis drug and vaccine development is limited by the poor tractability of the parasite, which includes a lack of systems for continuous culture, facile animal models, and molecular genetic tools. Here we describe an experimental framework to genetically modify this important human pathogen. We established and optimized transfection of C. parvum sporozoites in tissue culture. To isolate stable transgenics we developed a mouse model that delivers sporozoites directly into the intestine, a Cryptosporidium clustered regularly interspaced short palindromic repeat (CRISPR)/Cas9 system, and in vivo selection for aminoglycoside resistance. We derived reporter parasites suitable for in vitro and in vivo drug screening, and we evaluated the basis of drug susceptibility by gene knockout. We anticipate that the ability to genetically engineer this parasite will be transformative for Cryptosporidium research. Genetic reporters will provide quantitative correlates for disease, cure and protection, and the role of parasite genes in these processes is now open to rigorous investigation.