Methodological considerations for near-infrared spectroscopy to assess mitochondrial capacity after spinal cord injury

Background: Skeletal muscle mitochondrial activity is reduced by?～?50–60% after SCI, resulting in impaired energy expenditure, glucose utilization and insulin sensitivity. Near infra-red spectroscopy (NIRS) is a non-invasive tool that can be used to assess mitochondrial capacity.

Objectives: (1) Highlight methodological limitations impacting data acquisition and analysis such as subcutaneous adipose tissue (SAT) thickness, movement artifacts, inadequate muscle stimulation, light interference, and ischemic discomfort. (2) Provide technical considerations to improve data acquisition and analysis. This may serve as guidance to other researchers and clinicians using NIRS.

Study Design: cross-sectional observational design.

Settings: Clinical research medical center.

Participants: Sixteen men with 1?>?year post motor complete SCI.

Methods: NIRS signals were obtained from right vastus lateralis muscle utilizing a portable system. Signals were fit to a mono-exponential curve.

Outcome Measures: Rate constant and r ² values for the fit curve, indirectly measures mitochondrial capacity.

Results: Only four participants produced data with accepted rate constants of 0.002–0.013?s^?1 and r ² of 0.71–0.87. Applications of studentized residuals ≥2.5 resulted in sparing data from another four participants with rate constants of 0.010–0.018?s^?1and r ² values ranging from 0.86–0.99.

Conclusions: Several limitations may challenge the use of NIRS to assess mitochondrial capacity after SCI. Acknowledging these limitations and applying additional data processing techniques may overcome the discussed limitations and facilitate data sparing.     

Utilization of BIA-Derived Bone Mineral Estimates Exerts Minimal Impact on Body Fat Estimates via Multicompartment Models in Physically Active Adults

The purpose of this study was to compare body fat estimates and fat-free mass (FFM) characteristics produced by multicompartment models when utilizing either dual energy X-ray absorptiometry (DXA) or single-frequency bioelectrical impedance analysis (SF-BIA) for bone mineral content (BMC) in a sample of physically active adults. Body fat percentage (BF%) was estimated with 5-compartment (5C), 4-compartment (4C), 3-compartment (3C), and 2-compartment (2C) models, and DXA. The 5C-Wang with DXA for BMC (i.e., 5C-Wang_DXA) was the criterion. 5C-Wang using SF-BIA for BMC (i.e., 5C-Wang_BIA), 4C-Wang_DXA (DXA for BMC), 4C-Wang_BIA (BIA for BMC), and 3C-Siri all produced values similar to 5C-Wang_DXA (r?>?0.99; total error [TE]?<?0.83%; standard error of estimate?<?0.67%; 95% limits of agreement [LOAs]?<?±1.35%). The 2C models (2C-Pace, 2C-Siri, and 2C-Brozek) and DXA each produced similar standard error of estimate and 95% LOAs (2.13%–3.12% and ±4.15%–6.14%, respectively). Furthermore, 3C-Lohman_DXA (underwater weighing for body volume and DXA for BMC) and 3C-Lohman_BIA (underwater weighing for body volume and SF-BIA for BMC) produced the largest 95% LOAs (±5.94%–8.63%). The FFM characteristics (i.e., FFM density, water/FFM, mineral/FFM, and protein/FFM) for 5C-Wang_DXA and 5C-Wang_BIA were each compared with the “reference body” cadavers of Brozek et al. 5C-Wang_BIA FFM density differed significantly from the “reference body” in women (1.103?±?0.007?g/cm³; p?<?0.001), but no differences were observed for 5C-Wang_DXA or either 5C model in men. Moreover, water/FFM and mineral/FFM were significantly lower in men and women when comparing 5C-Wang_DXA and 5C-Wang_BIA with the “reference body,” whereas protein/FFM was significantly higher (all p?≤?0.001). 3C-Lohman_BIA and 3C-Lohman_DXA produced error similar to 2C models and DXA and are therefore not recommended multicompartment models. Although more advanced multicompartment models (e.g., 4C-Wang and 5C-Wang) can utilize BIA-derived BMC with minimal impact on body fat estimates, the increased accuracy of these models over 3C-Siri is minimal.     

A brief fall prevention intervention for manual wheelchair users with spinal cord injuries: A pilot study

Objective: To conduct a pilot study of an intervention to decrease fall incidence and concerns about falling among individuals living with Spinal Cord Injury who use manual wheelchairs full-time.

Design: Pre/post. After a baseline assessment, a structured intervention was implemented. The assessment protocol was repeated 12 weeks after the baseline assessment.

Setting: Research laboratory and community.

Participants: 18 individuals living with SCI who use a manual wheelchair full-time with an average age of 35.78?±?13.89 years, lived with SCI for 17.06?±?14.6 years; 61.1% were female.

Intervention: A 1:1, 45 minute, in-person intervention focused on factors associated with falls and concerns about falling: transfers skills and seated postural control.

Outcome measures: Participants reported fall incidence and completed the Spinal Cord Injury Fall Concerns Scale, Community Participation Indicators and the World Health Organization Quality of Life – short version (WHOQOL-BREF). Transfer quality was assessed with the Transfer Assessment Instrument (TAI) and seated postural control with the Function In Seating Test (FIST).

Results: Recruitment, assessment and delivery of the intervention were successfully completed. After exposure to the intervention, fall incidence significantly decreased, (P?=?0.047, d_{z ?}=?0.507) and FIST scores improved (P?=?0.035, d_z? =?0.54). Significant improvements were also found in the WHOQOL-BREF Physical (P?=?0.05, d_{z ?}=?1.566) and Psychological (P?=?0.040, d_{z ?}=?0.760) domains.

Conclusion: The feasibility of the structured intervention was established and the intervention has the potential to reduce fall incidence and improve quality of life among individuals living with SCI who use a wheelchair. Appropriately powered randomized controlled trials of the program are warranted.     

Lean Soft Tissue Mass Measured Using Dual-Energy X-Ray Absorptiometry Is an Effective Index for Assessing Change in Leg Skeletal Muscle Mass Following Exercise Training

It is difficult to precisely and easily estimate the changes in skeletal muscle mass (SMM) following exercise training. We aimed to assess whether the change in lean soft tissue mass measured using dual-energy X-ray absorptiometry (DXA) reflects the change in SMM measured using magnetic resonance imaging (MRI) following exercise training in both the leg and trunk regions. Anthropometry, DXA, and MRI measurements of the trunk and leg regions were obtained in 10 male college sumo wrestlers before and after exercise training (mean duration between measurements: ~2?yr). Contiguous magnetic resonance images with 1-cm slice thickness and without gap were obtained from the first cervical vertebra to the ankle joints as reference data. Skeletal muscle volume was calculated from the summation of the digitized cross-sectional areas. The volume measurements were converted into mass by using an assumed skeletal muscle density (1.041?g/cm³). Trunk and leg areas, using DXA regional computer-generated lines, were adjusted to coincide with each discrete region by using MRI. Although the change in the DXA-measured lean soft tissue mass in the trunk region was significantly different from that of the MRI-measured SMM (Cohen's d?=??1.3145, concordance correlation coefficient?=?0.26, p?<?0.01), the changes were similar in the leg region (Cohen's d?=?0.07, concordance correlation coefficient?=?0.87, p?=?0.88). The exercise training-induced change in lean soft tissue mass significantly correlated with that in SMM, both in the leg (r?=?0.88, p?<?0.01) and trunk (r?=?0.64, p?<?0.05) regions. Bland–Altman analysis did not indicate a bias for the changes in leg lean soft tissue mass and SMM following exercise training. These results suggest that lean soft tissue mass measured using DXA is an effective index for assessing change in leg SMM following exercise training.     

Measurement of Visceral Adipose Tissue in Persons With Spinal Cord Injury by Magnetic Resonance Imaging and Dual X-Ray Absorptiometry: Generation and Application of a Predictive Equation

Purpose: Dual energy X-ray absorptiometry (DXA) and magnetic resonance imaging (MRI) permits quantification of visceral adipose tissue (VAT). However, DXA has not been validated against MRI in persons with chronic spinal cord injury (SCI). A predictive equation was generated from the measurement of VAT by MRI, a “gold” standard to quantitate VAT, compared to that of DXA, a method with several practical advantages. Method: DXA and MRI scans were performed in 27 participants with SCI. MRI multiaxial images were captured for VAT analysis. DXA-VAT was quantified at the android region (DXA-VAT_ANDROID-VOL) using enCore software. Android regions of DXA and MRI were matched using android height. Volumes of multiaxial MRI-VAT and subcutaneous adipose tissue (SAT) were quantified for the android region (MRI-VAT_ANDROID-VOL, MRI-SAT_ANDROID-VOL) and total trunk (MRI-VAT_ANDROID-VOL). Linear regression analysis was used to establish the proposed predication equations. The prediction equations were then applied to an independent sample that consisted of 98 participants with SCI. Bland-Altman analysis was used to determine the limits of agreement. Results: DXA-VAT_ANDROID-VOL predicted 92% of the variance in MRI-VAT_ANDROID-VOL (SEE = 252.5, p < 0.0005) and 85% of the variance in MRI-VAT_TRUNK-VOL (SEE = 1526.9, p < 0.0005). DXA-SAT_ANDROID-VOL predicted 81.5% of the variance in MRI-SAT_ANDROID-VOL (SEE = 458.2, p < 0.0005). Bland-Altman analysis revealed a high level of agreement between MRI-VAT_ANDROID-VOL and DXA-VAT_ANDROID-VOL (mean bias = 58.45 cm³). A predicted mean DXA-VAT_ANDROID-VOL of 995.2 cm³ was estimated as the population-specific cut-off point for high levels of VAT. Conclusion: DXA-VAT_ANDROID-VOL may accurately predict MRI-VAT_ANDROID-VOL in persons with SCI. The ability of DXA to detect VAT changes in longitudinal studies in persons with SCI should be performed.     

Longitudinal changes in body composition and metabolic profile between exercise clinical trials in men with chronic spinal cord injury

Study design: Longitudinal design.

Objectives: The study was undertaken to determine the effects of cessation of exercise interventions on body composition and metabolic profiles in men with chronic SCI.

Settings: Clinical trials within a Medical Center.

Methods: Eleven men with motor complete SCI were followed on average over a period of 2.5 years. Six men were involved in two different exercise interventions (functional electrical stimulation cycling versus arm cycling ergometer), 5 days/week for 16 weeks (exercise group), and five men served as a control (control group). Anthropometrics and dual energy X-ray absorptiometry (DXA) were captured to measure changes in lean mass (LM), fat mass (FM), percentage FM before, immediately after exercise, and after a period of 2.5 years. Basal metabolic rate (BMR) and lipid panel were also measured.

Results: Thigh circumference increased by 8.5% following exercise (P?=?0.042) and remained 6.4% greater than baseline measurements (P?=?0.012). Leg LM increased by 9% following the exercise intervention (P?=?0.03) and decreased by 16% in the follow-up visit (P?=?0.02). Percentage trunk and total body FM increased by 4.5% (P?=?0.008) and 3.5% (P?=?0.019) in the follow-up visit, respectively, and whole body LM increased by 8.4% and decreased back by 5.4% following a 2.5 year-period. BMR significantly decreased by 15.5% following the exercise (P?=?0.029) interventions.

Conclusion: Exercise training is accompanied with positive changes in body composition as well as compensatory decrease in BMR, that regressed back following 2.5 years of exercise cessation. Participation in an exercise trial is unlikely to confound the measurements of a follow-up trial.     

Short-term effects of respiratory muscle training combined with the abdominal drawing-in maneuver on the decreased pulmonary function of individuals with chronic spinal cord injury: A pilot randomized controlled trial

Objective: To investigate the effects of respiratory muscle training (RMT) combined with the abdominal drawing-in maneuver (ADIM) on the pulmonary function in patients with chronic spinal cord injury (SCI).

Methods: Thirty-seven subjects with SCI (level of injury: C4–T6, time since injury: 4–5 years) were randomly allocated to three groups; the integrated training group (ITG), the RMT group (RMTG), and the control group (CG). The ITG performed RMT using an incentive respiratory spirometer (IRS) and the ADIM using a stabilizer. The RMTG received only RMT using an IRS. Subjects in the CG received alternative and routine physical therapy or usual care. The interventions were conducted over an eight-week period. Pulmonary function was evaluated using spirometry to measure the forced vital capacity (FVC) and forced expiratory volume in 1 second (FEV₁).

Results: The differences between the pre- and post-test values for FVC (0.47?±?0.05 versus 0.15?±?0.06 versus –0.03?±?0.01) and FEV₁ (0.74?±?0.07 versus 0.27?±?0.17 versus 0.02?±?0.67)were significant among the groups. Post-test, in the ITG, the FVC and FEV₁ values showed significant differences from those in the RMTG and CG (F?=?11.48 and 11.49, P?=?0.002 and 0.001). Furthermore, following the 8­week intervention, the change ratio values of the FVC and FEV₁ of the ITG were increased further by an average of 9.75% and 7.91%, respectively, compared with those of the RMTG.

Conclusion: These findings suggest positive evidence that RMT with additional ADIM training can improve pulmonary function in SCI pulmonary rehabilitation.     

Aquatic,deep water peak VO2 testing for individuals with spinal cord injury

Objective: To determine the reliability of peak VO₂ testing for individuals with spinal cord injury (SCI) in deep water and on land; and to examine the relationship between these two testing conditions.

Design: Reliability study.

Setting: Comprehensive rehabilitation center in Baltimore, MD, USA.

Participants: 17 participants (13 men, 4 women) with motor complete and incomplete SCI. Participants were randomized into either aquatic or arm cycle ergometer first measurements.

Intervention: Pilot study to assess peak VO₂.

Outcome measures: Peak VO₂ measured with metabolic cart in supported deep water with the addition of Aquatrainer® connection, and on land with arm cycle ergometer. Two trials were conducted for each condition with 48?h separating each test.

Results: Peak oxygen consumption reliability was statistically significant for both conditions, aquatic (r?=?0.93, P?<?0.001) and arm cycle ergometry (r?=?0.96, P?<?0.001). Additionally, aquatic and arm cycle peak VO₂ correlation existed (r?=?0.72, P?<?0.001). For these 17 participants, lower extremity motor score influenced supported, deep water peak VO₂, B?=?0.57, P?<?0.02, whereas age, sex, and weight did not impact deep water or ergometer values.

Conclusion: Determining peak VO₂ for individuals with SCI is highly reproducible for arm cycle ergometry and in deep water assessment. Additionally, aquatic, deep water peak VO₂ testing is valid when compared to arm cycle ergometry. Although the peak VO₂ relationship between deep water and arm cycle ergometry is high, variance in the two conditions does exist. Therefore, it is important to assess peak VO₂ via the same exercise modality utilized in the treatment intervention.     

Association of musculoskeletal pain,fear-avoidance factors,and quality of life in active manual wheelchair users with SCI: A pilot study

Objective: Limited evidence examines the association of psychological factors, such as fear of movement and pain catastrophizing, with musculoskeletal pain patterns in active manual wheelchair users with spinal cord injury (SCI). This study investigated the relationship among musculoskeletal pain, fear avoidance factors, quality of life (QoL), activity and duration of injury in individuals with SCI.

Design: Cross-sectional correlational.

Setting: Community setting.

Participants: Twenty-six individuals with SCI (age?=?42?±?14 years, duration manual wheelchair use?=?17?±?13 years, work/school/volunteer hours/week?=?31?±?14; recreation/sports hours/week 10?±?12).

Outcome Measures: Demographics and self-report measures including the Musculoskeletal Pain Survey (MPS), Wheelchair Users Shoulder Pain Index (WUSPI), Tampa Scale of Kinesiophobia (TSK-11), Pain Catastrophizing Scale (PCS), Fear of Pain (FPQ), Subjective Quality of Life Questionnaire (SQoL), and the Social Interaction Inventory (SII). Spearman’s rho (ρ) assessed correlation among measures.

Results: Strong association existed between age and duration of injury (ρ?=?0.66, P?<?0.001). SQoL offered a strong, direct correlation with age (ρ?=?0.63, P?=?0.01), duration of injury (ρ?=?0.70, P?=?0.001), and strong, inverse relationship with MPStotal (ρ?=??0.66, P?=?0.003) and MPS shoulder subscore (ρ?=??0.64, P?=?0.004). WUSPI demonstrated strong, inverse association with self-reported work hours (ρ?=??0.52, P?=?0.02) and a strong, direct relationship to PCS (ρ?=?0.79, P?=?<0001). PCS demonstrated a strong, inverse relationship to work/school/volunteer hours (ρ?=?0.71, P?<?0.001) and strong association to TSK-11_total (ρ?=?0.61, P?=?0.001). A moderate, inverse relationship was identified for recreational/sports hours and FPQ (ρ?=?0.48, P?=?0.03).

Conclusion: This cyclical relationship of musculoskeletal pain, reduced activity, and maladaptive psychological factors allude to interdependence of factors, supporting the multidisciplinary approach to care.     

Relationships between T-scores at the hip and bone mineral density at the distal femur and proximal tibia in persons with spinal cord injury

Objective: To identify T-score values at the total hip (TH) and femoral neck (FN) that correspond to the cutoff value of <0.60?g/cm² for heightened risk of fracture at the distal femur (DF) and proximal tibia (PT).

Design: Retrospective analysis of data in a research center’s database.

Setting: Community-based individuals with spinal cord injury (SCI).

Participants: 105 unique individuals with SCI.

Outcome Measurements: DXA derived areal BMD (aBMD) and T-score of the DF, PT, TH, and FN.

Results: The aBMD at the DF and PT regions were predictors of T-scores at the TH (R ²?=?0.63, P?<?0.001 and R ²?=?0.65, P?<?0.001) and FN (R ²?=?0.55, P?<?0.001 and R ²?=?0.58, P?<?0.001). Using the DF and PT aBMD of 0.60?g/cm² as a value below which fractures were more likely to occur, the predicted T-score was ?3.1 and ?3.5 at the TH and ?2.6 and ?2.9 at the FN, respectively. However, when the predicted and observed T-score values disagree outside the 95% limit of agreement, the predicted T-score values are lower than the measured T-score values, overestimating the measured values between ?2.0 and ?4.0 SD.

Conclusion: The DF and PT cutoff value for aBMD of 0.60?g/cm² was a moderate predictor of T-score values at the TH and FN, with considerable inaccuracies outside the clinically acceptable limits of agreement. As such, the direct measurement of knee aBMD in persons with SCI should be performed, whenever possible, prior to prescribing weight bearing upright activities, such as robotic exoskeletal-assisted walking.     

Effect of acute intermittent hypoxia on motor function in individuals with chronic spinal cord injury following ibuprofen pretreatment: A pilot study

Introduction: Acute intermittent hypoxia (AIH) enhances lower extremity motor function in humans with chronic incomplete spinal cord injury (SCI). AIH-induced spinal plasticity is inhibited by systemic inflammation in animal models. Since SCI is frequently associated with systemic inflammation in humans, we tested the hypothesis that pretreatment with the anti-inflammatory agent ibuprofen enhances the effects of AIH.

Methods: A randomized, double-blinded, placebo-controlled crossover design was used. Nine adults (mean age 51.1?±?13.1 years) with chronic motor-incomplete SCI (7.7?±?6.3 years post-injury) received a single dose of ibuprofen (800?mg) or placebo, 90 minutes prior to AIH. For AIH, 9% O₂ for 90 seconds was interspersed with 21% O₂ for 60 seconds. Maximal voluntary ankle plantar flexion isometric torque was assessed prior to, and at 0, 30, and 60 minutes post-AIH. Surface electromyography (EMG) of plantar flexor muscles was also recorded.

Results: Torque increased significantly after AIH at 30 (P?=?0.007; by ～20%) and 60 (P?2?=?0.17, P?2?=?0.17, P?Conclusions: AIH systematically increased lower extremity torque in individuals with chronic incomplete SCI, but there was no significant effect of ibuprofen pretreatment. Our study re-confirms the ability of AIH to enhance leg strength in persons with chronic incomplete SCI.     

Femoral neck cortical geometry measured with magnetic resonance imaging is associated with proximal femur strength

Introduction Magnetic resonance imaging (MRI) is a promising medical imaging technique that we used to assess femoral neck cortical geometry.Objectives Our primary objective was to assess whether cortical bone in the femoral neck assessed by MRI was associated with failure load in a simulated sideways fall, with and without adjustment for total bone size. Our secondary objective was to assess the reliability of the MRI measurements.Materials and methods We imaged 34 human cadaveric proximal femora using MRI and dual-energy X-ray absorptiometry (DXA). MRI measurements of cross-sectional geometry at the femoral neck were the cortical cross-sectional area (CoCSA_MRI), second area moment of inertia (x axis; Ix_MRI), and section modulus (x axis; Zx_MRI). DXA images were analyzed with the standard Hologic protocol. From DXA, we report the areal bone mineral density (aBMD_DXA) in the femoral neck and trochanteric subregions of interest. The femora were loaded to failure at 100 mm/s in a sideways fall configuration (15° internal rotation, 10° adduction).Results and observations Failure load (N) was the primary outcome. We observed that the femoral neck CoCSA_MRI and Ix_MRI were strongly associated with failure load (r ²=0.46 and 0.48, respectively). These associations were similar to those between femoral neck aBMD and failure load (r ²=0.40), but lower than the associations between trochanteric aBMD and failure load (r ²=0.70).Conclusion We report that MRI holds considerable promise for measuring cortical bone geometry in the femoral neck and for predicting strength at the proximal femur.     

Interval training elicits higher enjoyment versus moderate exercise in persons with spinal cord injury

Background: High intensity interval training (HIIT) is a robust and time-efficient approach to improve multiple health indices including maximal oxygen uptake (VO₂max). Despite the intense nature of HIIT, data in untrained adults report greater enjoyment of HIIT versus continuous exercise (CEX). However, this has yet to be investigated in persons with spinal cord injury (SCI).

Objective: To examine differences in enjoyment in response to CEX and HIIT in persons with SCI.

Design: Repeated measures, within-subjects design.

Setting: University laboratory in San Diego, CA.

Participants: Nine habitually active men and women (age?=?33.3?±?10.5 years) with chronic SCI.

Intervention: Participants performed progressive arm ergometry to volitional exhaustion to determine VO₂peak. During subsequent sessions, they completed CEX, sprint interval training (SIT), or HIIT in randomized order.

Outcome Measures: Physical activity enjoyment (PACES), affect, rating of perceived exertion (RPE), VO₂, and blood lactate concentration (BLa) were measured.

Results: Despite a higher VO₂, RPE, and BLa consequent with HIIT and SIT (P?, PACES was significantly higher (P?=?0.03) in response to HIIT (107.4?±?13.4) and SIT (103.7?±?12.5) compared to CEX (81.6?±?25.4). Fifty-five percent of participants preferred HIIT and 45% preferred SIT, with none identifying CEX as their preferred exercise mode.

Conclusion: Compared to CEX, brief sessions of submaximal or supramaximal interval training elicit higher enjoyment despite higher metabolic strain. The long-term efficacy and feasibility of HIIT in this population should be explored considering that it is not viewed as more aversive than CEX.     

Biochemical Markers and Obstructive Sleep Apnea Risk in Individuals After Long-Term Bariatric Surgery

Background

Individuals who have undergone long-term bariatric surgery may be at increased obstructive sleep apnea (OSA) risk. The purpose of this study was to estimate the frequency of OSA risk and its associations, via biochemical markers, in patients who have undergone long-term bariatric surgery.

Methods

This cross-sectional study evaluated patients after 5 years or more post Roux-en-Y gastric bypass. Biochemical markers, anthropometrics, and OSA risk, via the STOP-Bang score screening tool, were evaluated. Independent Student t, Pearson’s chi-squared, or correlation tests were applied, according to total OSA risk score groups or its isolated components.

Results

Among the 77 patients evaluated (88.3% female; body mass index?=?32.7?±?5.8 kg/ m²; postoperative time?=?9.9?±?3.1 years), 36 were at risk for OSA. OSA risk score was positively correlated to high-sensitivity C-reactive protein levels (r²?=?0.270; p?=?0.025), triglycerides (r²?=?0.338, p?=?0.004), total cholesterol (r²?=?0,262; p?=?0,028), and HbA1c (r²?=?0.332; p?=?0.005). Compared to each counterpart, basal insulin and triglycerides were higher among those who self-reported witnessed apnea (12.8?±?6.5 vs 8.1?±?3.8, p?=?0.013; 136.4?±?41.1 vs 88.5?±?34.8, p?=?0.001, respectively), while levels of total cholesterol and LDL-C were higher in participants who reported tiredness (183.9?±?27.0 vs 164.8?±?33.4, p?=?0.005; 105.9?±?24.4 vs 92.0?±?26.6, p?=?0.018). Participants with snoring also had higher levels of triglycerides (107?±?41.1 vs 83.7?±?33.9, p?=?0.010).

Conclusions

OSA risk was highly prevalent among patients who had undergone long-term bariatric surgery, as noted via increased STOP-Bang scores, as were isolated components related to inflammatory markers and lipid and glycemic profile.

Graphical Abstract

     

Increased serum renalase in hemodialysis patients: is it related to left ventricular hypertrophy?

Introduction: Left ventricular hypertrophy (LVH) is one of the most common cardiac abnormalities in patients with end stage renal disease (ESRD). Hypertension, diabetes, increased body mass index, gender, age, anemia, and hyperparathyroidism have been described as risk factors for LVH in patients on dialysis. However, there may be other risk factors which have not been described yet. Recent studies show that renalase is associated with cardiovascular events. The aim of this study was to reveal the relation between renalase, LVH in patients under hemodialysis (HD) treatment.

Methods: The study included 50?HD patients and 35 healthy controls. Serum renalase levels and left ventricle mass index (LVMI) were measured in all participants and the relation between these variables was examined.

Findings: LVMI was positively correlated with dialysis vintage and C-reactive protein (CRP) (r?=?0.387, p?=?0.005 and r?=?0.597, p?r?=??0.324, p?=?0.022 and r?=??0.499, p?r?=?0.263, p?=?0.065). Serum renalase levels were significantly higher in HD patients (212?±?127?ng/mL) compared to controls (116?±?67?ng/mL) (p?r?=?0.677, p?r?=?0.625, p?Discussion: In our study, LVMI was correlated with dialysis vintage, residual diuresis, CRP, and hemoglobin. LVMI tends to correlate with renalase and this correlation may be significant in studies with more patient numbers. The main parameters affecting renalase levels are dialysis vintage and serum creatinine.     

Agreement Between A 2-Dimensional Digital Image-Based 3-Compartment Body Composition Model and Dual Energy X-Ray Absorptiometry for The Estimation of Relative Adiposity

The purpose of this study was to compare relative adiposity (%Fat) derived from a 2-dimensional image-based 3-component (3C) model (%Fat_3C-IMAGE) and dual-energy X-ray absorptiometry (DXA) (%Fat_DXA) against a 5-component (5C) laboratory criterion (%Fat_5C). 57 participants were included (63.2% male, 84.2% White/Caucasian, 22.5±4.7 yrs., 23.9±2.8 kg/m²). For each participant, body mass and standing height were measured to the nearest 0.1 kg and 0.1 cm, respectively. A digital image of each participant was taken using a 9.7 inch, 16g iPad Air 2 and analyzed using a commercially available application (version 1.1.2, made Health and Fitness, USA) for the estimation of body volume (BV) and inclusion in %Fat_3C-IMAGE . %Fat_3C-IMAGE and %Fat_5C included measures of total body water derived from bioimpedance spectroscopy. The criterion %Fat_5C included BV estimates derived from underwater weighing and bone mineral content measures via DXA. %Fat_DXA estimates were calculated from a whole-body DXA scan. A standardized mean effect size (ES) assessed the magnitude of differences between models with values of 0.2, 0.5, and 0.8 for small, moderate, and large differences, respectively. Data are presented as mean ± standard deviation. A strong correlation (r = 0.94, p <.001) and small mean difference (ES = 0.24, p <.001) was observed between %Fat_3C-IMAGE (19.20±5.80) and %Fat_5C (17.69±6.20) whereas a strong correlation (r = 0.87, p <.001) and moderate-large mean difference (ES = 0.70, p <.001) was observed between %Fat_DXA (22.01±6.81) and %Fat_5C. Furthermore, %Fat_3C-IMAGE (SEE = 2.20 %Fat, TE= 2.6) exhibited smaller SEE and TE than %Fat_DXA (SEE = 3.14 %Fat, TE = 5.5). The 3C image-based model performed slightly better in our sample of young adults than the DXA 3C model. Thus, the 2D image analysis program provides an accurate and non-invasive estimate of %Fat within a 3C model in young adults. Compared to DXA, the 3C image-based model allows for a more cost-effective and portable method of body composition assessment, potentially increasing accessibility to multi-component methods.     

Changes in nutrient intake and inflammation following an anti-inflammatory diet in spinal cord injury

Objective: The objective of the current study was to describe the observed changes in nutrient intakes following a 3-month anti-inflammatory diet, and to explore potential relationships between the change in nutrients and the change in various inflammatory mediators.

Design: A secondary analysis of a prior randomized controlled clinical trial.

Setting: Individuals with SCI within the Niagara region.

Participants: Twenty individuals with various levels and severities of SCI.

Intervention: Three-month anti-inflammatory diet.

Outcome Measures: The change in nutrient intake and corresponding changes to various inflammatory mediators.

Results: The treatment group demonstrated a significant reduction in fat intake (P?=?0.02), a significant increase in protein intake (P?=?0.02), and no change in carbohydrates (P?=?0.23) or energy intake (P?=?0.10). The treatment group showed a significant increase in some nutrients with established anti-inflammatory properties including vitamins A, C, and E, and omega-3 fatty acids (P?<?0.01). Significant reductions in proinflammatory nutrients were observed including trans fatty acids (P?=?0.05), caffeine (P?<?0.01), and sodium (P?=?0.02). The treatment group also showed significant reductions in the proinflammatory mediators interferon-y (P?=?0.01), interleukin-1β (P?<?0.01), and interleukin-6 (P?<?0.05). Further, several proinflammatory mediators were negatively correlated with anti-inflammatory nutrients, including vitamin A, carotenoids, omega-3 fatty acids, and zinc.

Conclusion: This study provides evidence that dietary alterations are effective at reducing chronic inflammation in individuals with SCI and provides a preliminary assessment of the related nutrient changes.     

Circulating irisin levels reflect visceral adiposity in non-diabetic patients undergoing hemodialysis

Background: Recent evidence suggests that increased visceral adiposity is a strong independent risk factor for cardiovascular death and all-cause mortality in hemodialysis (HD) patients. Irisin, which is a novel myokine, can play critical roles in diabetes and adiposity. The purpose of our study was to investigate whether serum irisin levels are associated with body mass index, waist circumference (WC), and total fat mass in non-diabetic patients undergoing maintenance HD.

Methods: This cross-sectional study included 108 non-diabetic HD patients and 40 age- and sex-matched apparently healthy subjects. Serum irisin concentrations were determined using an enzyme-linked immunosorbent assay. Body fat composition (TBF-410 Tanita Body Composition Analyzer) was measured and calculated.

Results: Serum irisin levels did not differ between HD patients and the healthy controls (523.50?±?229.32 vs. 511.28?±?259.74, p?=?0.782). Serum irisin levels were associated with age (r?=?0.314; p?=0.006), HOMA-IR (r?=?0.472; p?=?0.003), WC (r?=?0.862; p?r?=?0.614; p?β?=?1.240, p?β?=?0.792, p?=?0.015) were the variables that were significantly associated with irisin concentrations (R^2?=^?0.684, p?Conclusions: These results suggest that serum irisin levels are related to visceral adiposity in non-diabetic HD patients.     

Auricular acupuncture for spinal cord injury related neuropathic pain: a pilot controlled clinical trial

Objective: To obtain preliminary data on the effects of an auricular acupuncture protocol, Battlefield Acupuncture (BFA), on self-reported pain intensity in persons with chronic Spinal Cord Injury (SCI) and neuropathic pain.

Design: Pilot randomized delayed entry single center crossover clinical trial at an outpatient rehabilitation and integrative medicine hospital center.

Methods: Chronic (> one year post injury) ASIA impairment scale A through D individuals with SCI with injury level from C3 through T12 and below level neuropathic pain with at least five on the Numeric Rating Scale (NRS) were recruited. Twenty-four subjects were randomized to either an eight-week once weekly ten-needle BFA protocol (n?=?13) or to a waiting list followed by the BFA protocol (n?=?11).

Outcome measures: The primary outcome measure was change in the pain severity NRS. Secondary outcome was the Global Impression of Change.

Results: Demographically there were no significant differences between groups. Mean pain scores at baseline were higher in acupuncture than control subjects (7.75?±?1.54 vs. 6.25?±?1.04, P?=?0.027). Although both groups reported significant reduction in pain during the trial period, the BFA group reported more pain reduction than the delayed entry group (average change in NRS at eight weeks –2.92?±?2.11 vs. ?1.13?±?2.14, P?=?0.065). There was a significant difference in groups when a group-by-time interaction in a mixed-effect repeated measures model (P?=?0.014).

Conclusion: This pilot study has provided proof of concept that BFA has clinically meaningful effect on the modulation of SCI neuropathic pain.