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Huntington's disease (HD) is a fatal, dominantly inherited neurodegenerative disorder caused by CAG trinucleotide expansion in exon 1 of the huntingtin (HTT) gene. Since the reduction of pathogenic mutant HTT messenger RNA is therapeutic, we developed a mutant allele-sensitive CAGEX RNA-targeting CRISPR-Cas13d system (Cas13d-CAGEX) that eliminates toxic CAGEX RNA in fibroblasts derived from patients with HD and induced pluripotent stem cell-derived neurons. We show that intrastriatal delivery of Cas13d-CAGEX via an adeno-associated viral vector selectively reduces mutant HTT mRNA and protein levels in the striatum of heterozygous zQ175 mice, a model of HD. This also led to improved motor coordination, attenuated striatal atrophy and reduction of mutant HTT protein aggregates. These phenotypic improvements lasted for at least eight months without adverse effects and with minimal off-target transcriptomic effects. Taken together, we demonstrate proof of principle of an RNA-targeting CRISPR-Cas13d system as a therapeutic approach for HD, a strategy with implications for the treatment of other dominantly inherited disorders.

BackgroundOptimal management of patients with stable chest pain relies on the prognostic information provided by noninvasive cardiovascular testing, but there are limited data from randomized trials comparing anatomic with functional testing.MethodsIn the PROMISE trial (Prospective Multicenter Imaging Study for Evaluation of Chest Pain), patients with stable chest pain and intermediate pretest probability for obstructive coronary artery disease (CAD) were randomly assigned to functional testing (exercise electrocardiography, nuclear stress, or stress echocardiography) or coronary computed tomography angiography (CTA). Site-based diagnostic test reports were classified as normal or mildly, moderately, or severely abnormal. The primary end point was death, myocardial infarction, or unstable angina hospitalizations over a median follow-up of 26.1 months.ResultsBoth the prevalence of normal test results and incidence rate of events in these patients were significantly lower among 4500 patients randomly assigned to CTA in comparison with 4602 patients randomly assigned to functional testing (33.4% versus 78.0%, and 0.9% versus 2.1%, respectively; both P10%) who had a normal functional test were reclassified as being mildly abnormal, the discriminatory capacity improved to 0.69 (95% CI, 0.64-0.74).ConclusionsCoronary CTA, by identifying patients at risk because of nonobstructive CAD, provides better prognostic information than functional testing in contemporary patients who have stable chest pain with a low burden of obstructive CAD, myocardial ischemia, and events.Clinical trial registrationURL: http://www.clinicaltrials.gov. Unique identifier: NCT01174550.

BackgroundDiagnostic testing in the care of patients newly presenting with symptoms suggestive of coronary artery disease may influence risk factor management, independent of test type or test results. However, little is known about changes in medications and lifestyle after anatomical or functional testing.Methods and resultsWe examined what factors influenced preventive medical therapy and lifestyle practices at 60 days among 10 003 symptomatic patients (53% women; mean age 61 years) randomly assigned to anatomical testing with coronary computed tomographic angiography or functional testing (NCT01174550). We also assessed the association of preventive changes with major cardiovascular events. There were no differences in medications/lifestyle at baseline. At 60 days, relative to baseline, the computed tomographic angiography strategy was associated with a higher proportion of patients newly initiating aspirin (11.8% versus 7.8%), statins (12.7% versus 6.2%), and β-blockers (8.1% versus 5.3%), compared to functional testing (P

Background: Diagnostic testing in the care of patients newly presenting with symptoms suggestive of coronary artery disease may influence risk factor management, independent of test type or test results. However, little is known about changes in medications and lifestyle after anatomical or functional testing. Methods and Results: We examined what factors influenced preventive medical therapy and lifestyle practices at 60 days among 10 003 symptomatic patients (53% women; mean age 61 years) randomly assigned to anatomical testing with coronary computed tomographic angiography or functional testing (NCT01174550). We also assessed the association of preventive changes with major cardiovascular events. There were no differences in medications/lifestyle at baseline. At 60 days, relative to baseline, the computed tomographic angiography strategy was associated with a higher proportion of patients newly initiating aspirin (11.8% versus 7.8%), statins (12.7% versus 6.2%), and β‐blockers (8.1% versus 5.3%), compared to functional testing (P<0.0001 for each). No significant differences between computed tomographic angiography and functional testing strategies were observed for initiation of exercise, quitting smoking, or weight loss in overweight/obese patients, though overall prevalence of healthy eating was higher after computed tomographic angiography (P=0.002) while obese/overweight status was lower (P=0.040). Positive initial test results and revascularization demonstrated stronger associations with preventive medications and lifestyle than test type. Medication initiation was not associated with fewer cardiovascular events. Conclusions: Positive initial test results and revascularization are primary drivers of changes in preventive medical and lifestyle practices, with test type making secondary contributions. However, substantial opportunities exist to further reduce cardiovascular risk. Clinical Trial Registration URL: https://www.clinicaltrials.gov. Unique identifier: NCT01174550.

Although caloric restriction (CR) could delay biologic aging in humans, it is unclear if this would occur at the cost of significant bone loss. We evaluated the effect of prolonged CR on bone metabolism and bone mineral density (BMD) in healthy younger adults. Two-hundred eighteen non-obese (body mass index [BMI] 25.1 ± 1.7 kg/m(2) ), younger (age 37.9 ± 7.2 years) adults were randomly assigned to 25% CR (CR group, n = 143) or ad libitum (AL group, n = 75) for 2 years. Main outcomes were BMD and markers of bone turnover. Other outcomes included body composition, bone-active hormones, nutrient intake, and physical activity. Body weight (-7.5 ± 0.4 versus 0.1 ± 0.5 kg), fat mass (-5.3 ± 0.3 versus 0.4 ± 0.4 kg), and fat-free mass (-2.2 ± 0.2 versus -0.2 ± 0.2 kg) decreased in the CR group compared with AL (all between group p < 0.001). Compared with AL, the CR group had greater changes in BMD at 24 months: lumbar spine (-0.013 ± 0.003 versus 0.007 ± 0.004 g/cm(2) ; p < 0.001), total hip (-0.017 ± 0.002 versus 0.001 ± 0.003 g/cm(2) ; p < 0.001), and femoral neck (-0.015 ± 0.003 versus -0.005 ± 0.004 g/cm(2) ; p = 0.03). Changes in bone markers were greater at 12 months for C-telopeptide (0.098 ± 0.012 versus 0.025 ± 0.015 μg/L; p < 0.001), tartrate-resistant acid phosphatase (0.4 ± 0.1 versus 0.2 ± 0.1 U/L; p = 0.004), and bone-specific alkaline phosphatase (BSAP) (-1.4 ± 0.4 versus -0.3 ± 0.5 U/L; p = 0.047) but not procollagen type 1 N-propeptide; at 24 months, only BSAP differed between groups (-1.5 ± 0.4 versus 0.9 ± 0.6 U/L; p = 0.001). The CR group had larger increases in 25-hydroxyvitamin D, cortisol, and adiponectin and decreases in leptin and insulin compared with AL. However, parathyroid hormone and IGF-1 levels did not differ between groups. The CR group also had lower levels of physical activity. Multiple regression analyses revealed that body composition, hormones, nutrients, and physical activity changes explained ∼31% of the variance in BMD and bone marker changes in the CR group. Therefore, bone loss at clinically important sites of osteoporotic fractures represents a potential limitation of prolonged CR for extending life span. Further long-term studies are needed to determine if CR-induced bone loss in healthy adults contributes to fracture risk and if bone loss can be prevented with exercise., (© 2015 American Society for Bone and Mineral Research.)