The Diagnosis and Management of Cardiometabolic Risk and Cardiometabolic Syndrome after Spinal Cord Injury.

Individuals with spinal cord injuries (SCI) commonly present with component risk factors for cardiometabolic risk and combined risk factors for cardiometabolic syndrome (CMS). These primary risk factors include obesity, dyslipidemia, dysglycemia/insulin resistance, and hypertension. Commonly referred to as "silent killers", cardiometabolic risk and CMS increase the threat of cardiovascular disease, a leading cause of death after SCI. This narrative review will examine current data and the etiopathogenesis of cardiometabolic risk, CMS, and cardiovascular disease associated with SCI, focusing on pivotal research on cardiometabolic sequelae from the last five years. The review will also provide current diagnosis and surveillance criteria for cardiometabolic disorders after SCI, a novel obesity classification system based on percent total body fat, and lifestyle management strategies to improve cardiometabolic health.

Center-level and region-level variations in liver transplantation practices following acuity circles policy change.

Although early studies suggest the Acuity Circles (AC) allocation policy has increased access to deceased donor liver transplants (DDLTs) for patients with the highest MELD scores, changes in center- and region-level practices among patients with the highest MELD scores in response to AC are not well-characterized. OPTN/UNOS data were analyzed to compare center-level changes in the number of DDLTs based on allocation-MELD (aMELD) categories used for AC sharing performed in the 18-month periods before and after AC enactment on February 4, 2020. There was large center-level variation in the number and proportion of aMELD ≥ 37 DDLTs performed from pre-AC to AC period; 13 centers accounted for 196 of the 198 total net increase in aMELD ≥ 37 DDLTs performed after AC, 5 of these being from UNOS region 5. Similar center-level variation was seen for MELD 33-36 and MELD 29-32 DDLTs, with 17 centers and 14 centers, respectively, accounting for the entire net increase in DDLTs in the aMELD categories. In conclusion, AC increased access to livers for transplantation for high MELD patients nationally, but imbalances remain in transplant practice patterns at the center and regional levels. Longer-term study is necessary to assess effectiveness of AC in improving equitability of liver transplantations.

Muscle strength, not age, explains unique variance in echo intensity.

Echo intensity (EI) is being increasingly utilized by investigators as an index of skeletal muscle quality. Previous studies have reported independent associations between EI versus both age and muscle strength. PURPOSE: We sought to determine whether EI is more strongly associated with age or strength. METHODS: Twenty-eight younger adults (13 men, 15 women; mean age = 22 years) and 25 older adults (10 men, 15 women; age = 71 years) participated. B-mode ultrasonography was utilized to acquire images of the vastus lateralis and rectus femoris. ImageJ software was used to quantify corrected EI and muscle cross-sectional area (CSA). Each participant performed 40 maximal concentric isokinetic muscle actions of the knee extensors (velocity = 180°·s-1). The mean peak torque of the best three attempts was used to quantify muscle strength. Specific torque was calculated as strength relative to CSA. Fatigability was also quantified. Statistical analyses included independent samples t-tests and stepwise regression. RESULTS: There were large differences between age groups for strength (p < .001, d = 1.831) and CSA (p = .003, d = 0.872). When corrected for subcutaneous tissue thickness, the difference in EI between age groups was small (p = .184, d = 0.371). Stepwise regression revealed that muscle strength was the single best predictor of EI (R2 = 0.206), with age, CSA, specific torque, and fatigability explaining no unique variance. CONCLUSION: Concentric isokinetic muscle strength is a better predictor of EI than age.

Age-, sex-, and region-specific differences in skeletal muscle size and quality.

Ultrasonography-derived cross-sectional area (CSA) and echo intensity (EI) are increasingly utilized by investigators to study muscle size and quality, respectively. We sought to examine age, sex, and region (proximal, middle, distal) differences in vastus lateralis and rectus femoris CSA and EI, and determine whether correction for subcutaneous fat thickness influences the magnitude of EI differences. Fifteen younger men (mean age = 23 years), 15 younger women (aged 21 years), 11 older men (aged 74 years), and 15 older women (aged 70 years) participated. Clear differences were observed among age, sex, and region for vastus lateralis CSA (p ≤ 0.013, d = 0.38-0.73), whereas rectus femoris CSA was only different between younger and older participants at the proximal region (p = 0.017, d = 0.65). Uncorrected EI was greatest at the distal region of both muscles (p < 0.001, d = 0.59-1.38), with only the younger men having significantly lower EI values than the other groups (p ≤ 0.043, d = 0.37-0.63). Subcutaneous fat correction resulted in a marked increase in the magnitude of sex-specific EI differences (p ≤ 0.032, d ≥ 0.42). Additionally, subcutaneous fat correction increased the uniformity of EI throughout the thigh. These findings highlight considerable region-specific differences in muscle size and quality among younger and older men and women and highlight the need to correct for subcutaneous fat thickness when examining EI. Novelty Rectus femoris CSA is similar between younger and older adults except at the most proximal site evaluated. Age- and sex-specific differences in uncorrected EI are nonuniform across the thigh. Correction for subcutaneous fat thickness substantially increased EI in women, resulting in greater sex differences.

Consistency of novel ultrasound equations for estimating percent intramuscular fat.

INTRODUCTION: Echo intensity reflects both intramuscular adiposity and fibrous tissue content. Recently, equations that allow investigators to estimate the percentage of intramuscular fat for individual muscles via measurements of echo intensity and subcutaneous fat were created. However, as the trial-to-trial consistency of these values has not been reported in the literature, it is unclear if they can be used to track changes during physical activity and/or nutritional interventions. The purpose of this study was to examine the test-retest reliability of rectus femoris percent intramuscular fat. METHODS: Nineteen healthy adults (mean ± SD age = 22 ± 3 year; ten females, nine males) with a body mass index ≤ 30 kg/m2 participated. On three occasions, B-mode ultrasonography was used to acquire panoramic images of the dominant rectus femoris in the transverse plane. ImageJ software was used to quantify echo intensity, subcutaneous fat thickness and cross-sectional area. Rectus femoris percent intramuscular fat was estimated with sex-specific equations. RESULTS: Uncorrected and corrected echo intensity, subcutaneous fat and cross-sectional area exhibited excellent consistency (P > 0·05, intraclass correlation coefficients [ICCs] ≥ .900, standard errors of measurement [SEMs] ≤ 7·26%). Percent intramuscular fat for all participants also demonstrated satisfactory reliability (ICC = 0·980, SEM = 3·07%), with similar findings for males (ICC = 0·970, SEM = 3·63%) and females (ICC = 0·968, SEM = 1·41%). DISCUSSION: The high ICCs and low SEMs suggest that ultrasonography-derived rectus femoris percent fat may be a reliable tool for tracking changes in lower extremity intramuscular adiposity.

Echo Intensity Versus Muscle Function Correlations in Older Adults are Influenced by Subcutaneous Fat Thickness.

Recently, an equation that allows investigators to correct echo intensity for subcutaneous fat was developed. We evaluated correlations between uncorrected and corrected echo intensity versus measures of lower-extremity function. Twenty-three older adults (11 men, 12 women; mean age = 72 y) participated. B-Mode ultrasonography was used to quantify rectus femoris echo intensity and subcutaneous fat thickness. Knee extensor isometric peak torque and rate of torque development at 200 ms (RTD200) were determined (joint angle = 90°). Fast gait speed was evaluated at 10- and 400-m distances. Partial correlations between normalized peak torque, RTD200 and 10- and 400-m gait speed versus uncorrected echo intensity were weak and insignificant. Correction for subcutaneous fat strengthened the correlations (peak torque r = -0.500, RTD200 r= -0.425, 10-m r = -0.409, 400-m r = -0.410). Correcting echo intensity values for subcutaneous fat strengthened the associations with lower-extremity muscle function in older adults.

Brief exposure to aversive stimuli impairs visual selective attention.

Although it is well established that stress can disrupt complex cognitive functions, relatively little is known about how it influences visual processing, especially in terms of visual selective attention. In the current study, we used highly aversive images, taken from the International Affective Picture System, to induce acute, low-intensity stress while participants performed a visual discrimination task. Consistent with prior research, we found that anticipation of aversive stimuli increased overall amplitude of the N170, suggesting an increase in early sensory gain. More importantly, we found that stress disrupted visual selective attention. While in no-stress blocks, the amplitude of the face-sensitive N170 was higher when participants attended to faces rather than scenes in face-scene overlay images; this effect was absent under stress. This was because of an increase in N170 amplitude in the scene-attend condition under stress. We interpret these findings as suggesting that even low-intensity acute stress can impair participants' ability to filter out task-irrelevant information. We discuss our findings in relation to how even brief exposure to low-intensity stress may adversely impact both healthy and clinical populations.