Mouse Studies to Shape Clinical Trials for Mitochondrial Diseases: High Fat Diet in Harlequin Mice

BACKGROUND: Therapeutic options in human mitochondrial oxidative phosphorylation (OXPHOS) diseases have been poorly evaluated mostly because of the scarcity of cohorts and the inter-individual variability of disease progression. Thus, while a high fat diet (HFD) is often recommended, data regarding efficacy are limited. Our objectives were 1) to determine our ability to evaluate therapeutic options in the Harlequin OXPHOS complex I (CI)-deficient mice, in the context of a mitochondrial disease with human hallmarks and 2) to assess the effects of a HFD. METHODS AND FINDINGS: Before launching long and expensive animal studies, we showed that palmitate afforded long-term death-protection in 3 CI-mutant human fibroblasts cell lines. We next demonstrated that using the Harlequin mouse, it was possible to draw solid conclusions on the efficacy of a 5-month-HFD on neurodegenerative symptoms. Moreover, we could identify a group of highly responsive animals, echoing the high variability of the disease progression in Harlequin mice. CONCLUSIONS: These results suggest that a reduced number of patients with identical genetic disease should be sufficient to reach firm conclusions as far as the potential existence of responders and non responders is recognized. They also positively prefigure HFD-trials in OXPHOS-deficient patients

Efficacy and Safety of Ticagrelor Monotherapy by Clinical Presentation: Pre-Specified Analysis of the GLOBAL LEADERS Trial.

Background The optimal duration of dual antiplatelet therapy after coronary drug-eluting stent placement in adults with stable coronary artery disease (SCAD) versus acute coronary syndromes (ACS) remains uncertain. Methods and Results This was a prespecified subgroup analysis of the GLOBAL LEADERS trial. Participants were randomly assigned 1:1 to the experimental or reference strategy, stratified by ACS (experimental, n=3750; reference, n=3737) versus SCAD (experimental, n=4230; reference, n=4251). The experimental strategy was 75 to 100 mg aspirin daily plus 90 mg ticagrelor twice daily for 1 month, followed by 23 months of ticagrelor monotherapy. The reference strategy was 75 to 100 mg aspirin daily plus either 75 mg clopidogrel daily (for SCAD) or 90 mg ticagrelor twice daily (for ACS) for 12 months, followed by aspirin monotherapy for 12 months. The primary end point at 2 years was a composite of all-cause mortality or non-fatal centrally adjudicated new Q-wave myocardial infarction. The key secondary safety end point was site-reported Bleeding Academic Research Consortium grade 3 or 5 bleeding. The primary end point occurred in 147 (3.92%) versus 169 (4.52%) patients with ACS (rate ratio [RR], 0.86; 95% CI, 0.69-1.08; P=0.189), and in 157 (3.71%) versus 180 (4.23%) patients with SCAD (RR, 0.87; 95% CI, 0.71-1.08; P=0.221) with experimental and reference strategy, respectively (P-interaction=0.926). Bleeding Academic Research Consortium grade 3 or 5 bleeding occurred in 73 (1.95%) versus 100 (2.68%) patients with ACS (RR, 0.73; 95% CI, 0.54-0.98; P=0.037), and in 90 (2.13%) versus 69 (1.62%) patients with SCAD (RR, 1.32; 95% CI, 0.97-1.81; P=0.081; P-interaction=0.007). Conclusions While there was no evidence for differences in efficacy between treatment strategies by subgroup, the experimental strategy appeared to reduce bleeding risk in patients with ACS but not in patients with SCAD. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT01813435

The Variability of the Harlequin Mouse Phenotype Resembles that of Human Mitochondrial-Complex I-Deficiency Syndromes

Background: Despite the considerable progress made in understanding the molecular bases of mitochondrial diseases, no effective treatments have been developed to date. Faithful animal models would be extremely helpful for designing such treatments. We showed previously that the Harlequin mouse phenotype was due to a specific mitochondrial complex I deficiency resulting from the loss of the Apoptosis Inducing Factor (Aif) protein. Methodology/Principal Findings: Here, we conducted a detailed evaluation of the Harlequin mouse phenotype, including the biochemical abnormalities in various tissues. We observed highly variable disease expression considering both severity and time course progression. In each tissue, abnormalities correlated with the residual amount of the respiratory chain complex I 20 kDa subunit, rather than with residual Aif protein. Antioxidant enzyme activities were normal except in skeletal muscle, where they were moderately elevated. Conclusions/Significance: Thus, the Harlequin mouse phenotype appears to result from mitochondrial respiratory chain complex I deficiency. Its features resemble those of human complex I deficiency syndromes. The Harlequin mouse hold

Ticagrelor Monotherapy or Dual Antiplatelet Therapy After Drug-Eluting Stent Implantation: Per-Protocol Analysis of the GLOBAL LEADERS Trial.

Background In the GLOBAL LEADERS trial, ticagrelor monotherapy beyond 1 month compared with standard antiplatelet regimens after coronary stent implantation did not improve outcomes at intention-to-treat analysis. Considerable differences in treatment adherence between the experimental and control groups may have affected the intention-to-treat results. In this reanalysis of the GLOBAL LEADERS trial, we compared the experimental and control treatment strategies in a per-protocol analysis of patients who did not deviate from the study protocol. Methods and Results Baseline and postrandomization information were used to classify whether and when patients were deviating from the study protocol. With logistic regressions, we derived time-varying inverse probabilities of nondeviation from protocol to reconstruct the trial population without protocol deviation. The primary end point was a composite of all-cause mortality or nonfatal Q-wave myocardial infarction at 2 years. At 2-year follow-up, 1103 (13.8%) of 7980 patients in the experimental group and 785 (9.8%) of 7988 patients in the control group qualified as protocol deviators. At per-protocol analysis, the rate ratio for the primary end point was 0.88 (95% CI, 0.75-1.03; P=0.10) on the basis of 274 versus 325 events in the experimental versus control group. The rate ratio for the key safety end point of major bleeding was 1.00 (95% CI, 0.79-1.26; P=0.99). The per-protocol and intention-to-treat effect estimates were overall consistent. Conclusions Among patients who complied with the study protocol in the GLOBAL LEADERS trial, ticagrelor plus aspirin for 1 month followed by ticagrelor monotherapy was not superior to 1-year standard dual antiplatelet therapy followed by aspirin alone at 2 years after coronary stenting. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT01813435

The Warburg Effect Is Genetically Determined in Inherited Pheochromocytomas

The Warburg effect describes how cancer cells down-regulate their aerobic respiration and preferentially use glycolysis to generate energy. To evaluate the link between hypoxia and Warburg effect, we studied mitochondrial electron transport, angiogenesis and glycolysis in pheochromocytomas induced by germ-line mutations in VHL, RET, NF1 and SDH genes. SDH and VHL gene mutations have been shown to lead to the activation of hypoxic response, even in normoxic conditions, a process now referred to as pseudohypoxia. We observed a decrease in electron transport protein expression and activity, associated with increased angiogenesis in SDH- and VHL-related, pseudohypoxic tumors, while stimulation of glycolysis was solely observed in VHL tumors. Moreover, microarray analyses revealed that expression of genes involved in these metabolic pathways is an efficient tool for classification of pheochromocytomas in accordance with the predisposition gene mutated. Our data suggest an unexpected association between pseudohypoxia and loss of p53, which leads to a distinct Warburg effect in VHL-related pheochromocytomas

The First Sequenced Carnivore Genome Shows Complex Host-Endogenous Retrovirus Relationships

Host-retrovirus interactions influence the genomic landscape and have contributed substantially to mammalian genome evolution. To gain further insights, we analyzed a female boxer (Canis familiaris) genome for complexity and integration pattern of canine endogenous retroviruses (CfERV). Intriguingly, the first such in-depth analysis of a carnivore species identified 407 CfERV proviruses that represent only 0.15% of the dog genome. In comparison, the same detection criteria identified about six times more HERV proviruses in the human genome that has been estimated to contain a total of 8% retroviral DNA including solitary LTRs. These observed differences in man and dog are likely due to different mechanisms to purge, restrict and protect their genomes against retroviruses. A novel group of gammaretrovirus-like CfERV with high similarity to HERV-Fc1 was found to have potential for active retrotransposition and possibly lateral transmissions between dog and human as a result of close interactions during at least 10.000 years. The CfERV integration landscape showed a non-uniform intra- and inter-chromosomal distribution. Like in other species, different densities of ERVs were observed. Some chromosomal regions were essentially devoid of CfERVs whereas other regions had large numbers of integrations in agreement with distinct selective pressures at different loci. Most CfERVs were integrated in antisense orientation within 100 kb from annotated protein-coding genes. This integration pattern provides evidence for selection against CfERVs in sense orientation relative to chromosomal genes. In conclusion, this ERV analysis of the first carnivorous species supports the notion that different mammals interact distinctively with endogenous retroviruses and suggests that retroviral lateral transmissions between dog and human may have occurred