Natural history of mitochondrial disorders: a systematic review

The natural history of a disease defines the age of onset, presenting features, clinical phenotype, morbidity and mortality outcomes of disease that is unmodified by treatments. A clear understanding of the natural history of mitochondrial disorders is essential for establishing genotype-phenotype-prognosis correlations. We performed a systematic review of the reported natural history of mitochondrial disease by searching the literature for all published natural history studies containing at least 20 individuals. We defined a phenotype as 'common' if it was observed in ≥30% of cases in a study, thereby highlighting common and uncommon phenotypes for each disorder. Thirty-seven natural history studies were identified encompassing 29 mitochondrial disease entities. Fifty-nine percent of disorders had an onset before 18 months and 81% before 18 years. Most disorders had multisystemic involvement and most often affected were the central nervous system, eyes, gastrointestinal system, skeletal muscle, auditory system and the heart. Less frequent involvement was seen for respiratory, renal, endocrine, hepatic, haematological and genitourinary systems. Elevated lactate was the most frequent biochemical abnormality, seen in 72% of disorders. Age of death was <1 y in 13% of disorders, <5 y in 57% and <10 y in 74%. Disorders with high mortality rates were generally associated with earlier deaths. The most robust indicators of poor prognosis were early presentation of disease and truncating mutations. A thorough knowledge of natural history has helped to redefine diagnostic criteria for classical clinical syndromes and to establish a clinical baseline for comparison in single-arm clinical trials of novel therapies

Moving Towards Clinical Trials for Mitochondrial Diseases

Primary mitochondrial diseases represent some of the most common and severe inherited metabolic disorders, affecting approximately 1 in 4300 live births. The clinical and molecular diversity typified by mitochondrial diseases has contributed to the lack of licensed disease‐modifying therapies available. Management for the majority of patients is primarily supportive. The failure of clinical trials in mitochondrial disease partly relates to the inefficacy of compounds studied. However, it is also likely to be a consequence of the significant challenges faced by clinicians and researchers when designing trials for mitochondrial diseases, which have historically been hampered by a lack of natural history data, biomarkers and outcome measures to detect a treatment effect. Encouragingly, over the past decade there have been significant advances in therapy development for mitochondrial diseases, with many small molecules now transitioning from preclinical to early phase human interventional studies. In this review, we present the treatments and management strategies currently available to people with mitochondrial disease. We evaluate the challenges and potential solutions to trial design and highlight the emerging pharmacological and genetic strategies that are moving from the laboratory to clinical trials for this group of disorders

Fast Differentially Private Matrix Factorization

Differentially private collaborative filtering is a challenging task, both in terms of accuracy and speed. We present a simple algorithm that is provably differentially private, while offering good performance, using a novel connection of differential privacy to Bayesian posterior sampling via Stochastic Gradient Langevin Dynamics. Due to its simplicity the algorithm lends itself to efficient implementation. By careful systems design and by exploiting the power law behavior of the data to maximize CPU cache bandwidth we are able to generate 1024 dimensional models at a rate of 8.5 million recommendations per second on a single PC

Dehydration of potato slices following brief dipping in osmotic solutions: effect of conditions and understanding the mechanism of water loss

A novel variant of osmotic dehydration, named here as post-dipping dehydration – where a material is dipped in a salt or sugar solution for a very short time followed by simple exposure to ambient conditions was explored with the aim of lowering water content of potato slices but at the same time not gain a high level of sugar/salt. The rate of water loss, which was rapid initially, was found to approach equilibrium. This paper also explored whether the water loss process could subsequently be kick started once again, by employing a multi-stage process, where each stage consisted of osmotic solution dipping followed by ambient holding of the potato slices that had reached equilibrium in the earlier stage. Water loss values comparable to conventional osmotic dehydration could be achieved thus, but with significantly lower overall solid gain (less than 50%) – which can potentially yield a significantly healthy product option

Cerebrospinal fluid metallomics in cerebral amyloid angiopathy: an exploratory analysis.

INTRODUCTION: Cerebral amyloid angiopathy (CAA) is associated with symptomatic intracerebral haemorrhage. Biomarkers of clinically silent bleeding events, such as cerebrospinal fluid (CSF) ferritin and iron, might provide novel measures of disease presence and severity. METHODS: We performed an exploratory study comparing CSF iron, ferritin, and other metal levels in patients with CAA, control subjects (CS) and patients with Alzheimer's disease (AD). Ferritin was measured using a latex fixation test; metal analyses were performed using inductively coupled plasma mass spectrometry. RESULTS: CAA patients (n = 10) had higher levels of CSF iron than the AD (n = 20) and CS (n = 10) groups (medians 23.42, 15.48 and 17.71 μg/L, respectively, p = 0.0015); the difference between CAA and AD groups was significant in unadjusted and age-adjusted analyses. We observed a difference in CSF ferritin (medians 10.10, 7.77 and 8.01 ng/ml, for CAA, AD and CS groups, respectively, p = 0.01); the difference between the CAA and AD groups was significant in unadjusted, but not age-adjusted, analyses. We also observed differences between the CAA and AD groups in CSF nickel and cobalt (unadjusted analyses). CONCLUSIONS: In this exploratory study, we provide preliminary evidence for a distinct CSF metallomic profile in patients with CAA. Replication and validation of these results in larger cohorts is needed

Subjective cognitive complaints at age 70: associations with amyloid and mental health.

OBJECTIVE: To investigate subjective cognitive decline (SCD) in relation to β-amyloid pathology and to test for associations with anxiety, depression, objective cognition and family history of dementia in the Insight 46 study. METHODS: Cognitively unimpaired ~70-year-old participants, all born in the same week in 1946 (n=460, 49% female, 18% amyloid-positive), underwent assessments including the SCD-Questionnaire (MyCog). MyCog scores were evaluated with respect to 18F-Florbetapir-PET amyloid status (positive/negative). Associations with anxiety, depression, objective cognition (measured by the Preclinical Alzheimer Cognitive Composite, PACC) and family history of dementia were also investigated. The informant's perspective on SCD was evaluated in relation to MyCog score. RESULTS: Anxiety (mean (SD) trait anxiety score: 4.4 (3.9)) was associated with higher MyCog scores, especially in women. MyCog scores were higher in amyloid-positive compared with amyloid-negative individuals (adjusted means (95% CIs): 5.3 (4.4 to 6.1) vs 4.3 (3.9 to 4.7), p=0.044), after accounting for differences in anxiety. PACC (mean (SD) -0.05 (0.68)) and family history of dementia (prevalence: 23.9%) were not independently associated with MyCog scores. The informant's perception of SCD was generally in accordance with that of the participant. CONCLUSIONS: This cross-sectional study demonstrates that symptoms of SCD are associated with both β-amyloid pathology, and more consistently, trait anxiety in a population-based cohort of older adults, at an age when those who are destined to develop dementia are still likely to be some years away from symptoms. This highlights the necessity of considering anxiety symptoms when assessing Alzheimer's disease pathology and SCD

Safety of drug use in patients with a primary mitochondrial disease: An international Delphi-based consensus

Clinical guidance is often sought when prescribing drugs for patients with primary mitochondrial disease. Theoretical considerations concerning drug safety in patients with mitochondrial disease may lead to unnecessary withholding of a drug in a situation of clinical need. The aim of this study was to develop consensus on safe medication use in patients with a primary mitochondrial disease. A panel of 16 experts in mitochondrial medicine, pharmacology, and basic science from six different countries was established. A modified Delphi technique was used to allow the panellists to consider draft recommendations anonymously in two Delphi rounds with predetermined levels of agreement. This process was supported by a review of the available literature and a consensus conference that included the panellists and representatives of patient advocacy groups. A high level of consensus was reached regarding the safety of all 46 reviewed drugs, with the knowledge that the risk of adverse events is influenced both by individual patient risk factors and choice of drug or drug class. This paper details the consensus guidelines of an expert panel and provides an important update of previously established guidelines in safe medication use in patients with primary mitochondrial disease. Specific drugs, drug groups, and clinical or genetic conditions are described separately as they require special attention. It is important to emphasise that consensus-based information is useful to provide guidance, but that decisions related to drug prescribing should always be tailored to the specific needs and risks of each individual patient. We aim to present what is current knowledge and plan to update this regularly both to include new drugs and to review those currently included