Hand Grip Strength Predicts Mortality and Quality of Life in Heart Failure: Insights From the Singapore Cohort of Patients With Advanced Heart Failure.

BACKGROUND: Frailty is prevalent among patients with heart failure (HF) and is associated with increased mortality rates and worse patient-centered outcomes. Hand grip strength (GS) has been proposed as a single-item marker of frailty and a potential screening tool to identify patients most likely to benefit from therapies that target frailty so as to improve quality of life (QoL) and clinical outcomes. We assessed the association of longitudinal decline in GS with all-cause mortality and QoL. Decline in GS is associated with increased risk of all-cause mortality and worse overall and domain-specific (physical, functional, emotional, social) QoL among patients with advanced HF. METHODS: We used data from a prospective, observational cohort of patients with New York Heart Association class III or IV HF in Singapore. Patients' overall and domain-specific QoL were assessed, and GS was measured every 4 months. We constructed a Kaplan-Meier plot with GS at baseline dichotomized into categories of weak (≤ 5th percentile) and normal (> 5th percentile) based on the GS in a healthy Singapore population of the same sex and age. Missing GS measurements were imputed using chained equations. We jointly modeled longitudinal GS measurements and survival time, adjusting for comorbidities. We used mixed effects models to evaluate the associations between GS and QoL. RESULTS: Among 251 patients (mean age 66.5 ± 12.0 years; 28.3% female), all-cause mortality occurred in 58 (23.1%) patients over a mean follow-up duration of 3.0 ± 1.3 years. Patients with weak GS had decreased survival rates compared to those with normal GS (log-rank P = 0.033). In the joint model of longitudinal GS and survival time, a decrease of 1 unit in GS was associated with a 12% increase in rate of mortality (hazard ratio: 1.12; 95% confidence interval: 1.05-1.20; P = < 0.001). Higher GS was associated with higher overall QoL (ß (SE) = 0.36 (0.07); P = < 0.001) and higher domain-specific QoL, including physical (ß [SE] = 0.13 [0.03]; P = < 0.001), functional (ß [SE] = 0.12 [0.03]; P = < 0.001), and emotional QoL (ß [SE] = 0.08 [0.02]; P = < 0.001). Higher GS was associated with higher social QoL, but this was not statistically significant (ß [SE] = 0.04 [0.03]; P = 0.122). CONCLUSIONS: Among patients with advanced HF, longitudinal decline in GS was associated with worse survival rates and QoL. Further studies are needed to evaluate whether incorporating GS into patient selection for HF therapies leads to improved survival rates and patient-centered outcomes.

Assessing the Success and Sustainability of Global Neurosurgery Collaborations: Systematic Review and Adaptation of the Framework for Assessment of InteRNational Surgical Success Criteria.

BACKGROUND: The high unmet neurosurgical burden in low- and middle-income countries has necessitated multiple global neurosurgical collaborations. We identified these collaborations and their peer-reviewed journal publications and evaluated them using a modified version of the Framework for Assessment of InteRNational Surgical Success (FAIRNeSS). METHODS: A systematic literature review yielded 265 articles describing neurosurgery-focused collaborations. A subset of 101 papers from 17 collaborations were evaluated with the modified FAIRNeSS criteria. Analysis of trends was performed for both individual articles and collaborations. RESULTS: Most of the articles were general reviews (64), and most focused on clinical research (115). The leading collaboration focus was workforce and infrastructure development (45%). Composite FAIRNeSS scores ranged from 7/34 to 30/34. Average FAIRNeSS scores for individual articles ranged from 0.25 to 26.75, while collaboration-wide FAIRNeSS score averages ranged from 5.25 to 20.04. There was significant variability within each subset of FAIRNeSS indicators (P value <0.001). Short-term goals had higher scores than medium- and long-term goals (P value <0.001). Collaboration composite scores correlated with the number of papers published (R2 = 0.400, P = 0.007) but not with the number of years active (R2 = 0.072, P = 0.3). Finally, the overall agreement between reviewers was 53.5%, and the overall correlation was 38.5%. CONCLUSIONS: Global neurosurgery has no established metrics for evaluating collaborations; therefore, we adapted the FAIRNeSS criteria to do so. The criteria may not be well suited for measuring the success and sustainability of global neurosurgery collaborations, creating a need to develop a more applicable alternate set of metrics.

Dopamine D2 receptors bidirectionally regulate striatal enkephalin expression: Implications for cocaine reward.

Low dopamine D2 receptor (D2R) availability in the striatum can predispose for cocaine abuse; though how low striatal D2Rs facilitate cocaine reward is unclear. Overexpression of D2Rs in striatal neurons or activation of D2Rs by acute cocaine suppresses striatal Penk mRNA. Conversely, low D2Rs in D2-striatal neurons increases striatal Penk mRNA and enkephalin peptide tone, an endogenous mu-opioid agonist. In brain slices, met-enkephalin and inhibition of enkephalin catabolism suppresses intra-striatal GABA transmission. Pairing cocaine with intra-accumbens met-enkephalin during place conditioning facilitates acquisition of preference, while mu-opioid receptor antagonist blocks preference in wild-type mice. We propose that heightened striatal enkephalin potentiates cocaine reward by suppressing intra-striatal GABA to enhance striatal output. Surprisingly, a mu-opioid receptor antagonist does not block cocaine preference in mice with low striatal D2Rs, implicating other opioid receptors. The bidirectional regulation of enkephalin by D2R activity and cocaine offers insights into mechanisms underlying the vulnerability for cocaine abuse.

Genetic and Environmental Contributions to Variation in the Posterior Communicating Collaterals of the Circle of Willis.

Variation in blood flow mediated by the posterior communicating collateral arteries (PComs) contributes to variation in the severity of tissue injury in obstructive disease. Evidence in animals and humans indicates that differences in the extent of PComs, i.e., their anatomic lumen diameter and whether they are present bilaterally, unilaterally, or absent, are a major factor. These differences arise during development since they are present at birth. However, the causal mechanisms are unknown. We used angiography after maximal dilation to examine involvement of genetic, environmental, and stochastic factors. The extent of PComs varied widely among seven genetically diverse strains of mice. Like pial collaterals in the microcirculation, aging and hypertension reduced PCom diameter, while in contrast, obesity, hyperlipidemia, metabolic syndrome, and diabetes mellitus had no effect. Naturally occurring intrauterine growth restriction had no effect on extent of PCom or pial collaterals in the adult. The number and diameter of PComs evidenced much larger apparent stochastic-dependent variation than pial collaterals. In addition, both PComs underwent flow-mediated outward remodeling after unilateral permanent MCA occlusion that varied with genetic background and was greater on the ipsilesional side. These findings indicate that variation in the number and diameter of PCom collateral arteries arises from stochastic factors and naturally occurring genetic variants that differ from those that cause variation in pial collateral arterioles. Environmental factors also contribute: aging and hypertension reduce PCom diameter. Our results suggest possible sources of variation of PComs in humans and provide information relevant when studying mouse models of occlusive cerebrovascular disease.