Role of pulsatile growth hormone (GH) secretion in the regulation of lipolysis in fasting humans.

BACKGROUND: The increase in growth hormone (GH) secretion during a prolonged fast stimulates lipolytic rate, thereby augmenting the mobilization of endogenous energy at a time when fuel availability is very low. STUDY AIM: To identify the specific component of GH secretory pattern responsible for the stimulation of lipolytic rate during fasting in humans. STUDY PROTOCOL: We measured lipolytic rate (using stable isotope dilution technique) after an overnight fast in 15 young, healthy, non-obese subjects (11 men and 4 women), and again on four separate occasions after a 59 h fast. These four prolonged fasting trials differed only by the contents of an infusion solution provided throughout the 59 h fasting period. Subjects were infused either with normal saline ("Control"; n = 15) or with graded doses of a GH Releasing Hormone Receptor Antagonist (GHRHa):10 µg/kg/h ("High"; n = 15), 1 µg /kg/h ("Medium"; n = 8), or 0.5 µg /kg/h ("Low"; n = 6). RESULTS: As expected, the 59 h fast completely suppressed plasma insulin levels and markedly increased endogenous GH concentrations (12 h vs 59 h Fast; p = 0.0044). Administration of GHRHa induced dose-dependent reduction in GH concentrations in response to the 59 h fast (p < 0.05). We found a strong correlation between the rate of lipolysis and GH mean peak amplitude (R = 0.471; p = 0.0019), and total GH pulse area under the curve (AUC) (R = 0.49; p = 0.0015), but not the GH peak frequency (R = 0.044; p = 0.8) or interpulse GH concentrations (R = 0.25; p = 0.115). CONCLUSION: During prolonged fasting (i.e., 2-3 days), when insulin secretion is abolished, the pulsatile component of GH secretion becomes a key metabolic regulator of the increase in lipolytic rate.

Bone and non-contractile soft tissue changes following open kinetic chain resistance training and testosterone treatment in spinal cord injury: an exploratory study.

Twenty men with spinal cord injury (SCI) were randomized into two 16-week intervention groups receiving testosterone treatment (TT) or TT combined with resistance training (TT + RT). TT + RT appears to hold the potential to reverse or slow down bone loss following SCI if provided over a longer period. INTRODUCTION: Persons with SCI experience bone loss below the level of injury. The combined effects of resistance training and TT on bone quality following SCI remain unknown. METHODS: Men with SCI were randomized into 16-week treatments receiving TT or TT + RT. Magnetic resonance imaging (MRI) of the right lower extremity before participation and post-intervention was used to visualize the proximal, middle, and distal femoral shaft, the quadriceps tendon, and the intermuscular fascia of the quadriceps. For the TT + RT group, MRI microarchitecture techniques were utilized to elucidate trabecular changes around the knee. Individual mixed models were used to estimate effect sizes. RESULTS: Twenty participants completed the pilot trial. A small effect for yellow marrow in the distal femur was indicated as increases following TT and decreases following TT + RT were observed. Another small effect was observed as the TT + RT group displayed greater increases in intermuscular fascia length than the TT arm. Distal femur trabecular changes for the TT + RT group were generally small in effect (decreased trabecular thickness variability, spacing, and spacing variability; increased network area). Medium effects were generally observed in the proximal tibia (increased plate width, trabecular thickness, and network area; decreased trabecular spacing and spacing variability). CONCLUSIONS: This pilot suggests longer TT + RT interventions may be a viable rehabilitation technique to combat bone loss following SCI. CLINICAL TRIAL REGISTRATION: Registered with clinicaltrials.gov : NCT01652040 (07/27/2012).

Body composition changes after 12 months of FES cycling: case report of a 60-year-old female with paraplegia.

STUDY DESIGN: Single-subject (female, 60 years of age) case. OBJECTIVES: The purpose of this case report is to document body composition changes in a 60-year-old female with chronic paraplegia after 12 months of home-based functional electrical stimulation lower extremities cycling (FES-LEC). SETTING: Home-based FES-LEC with internet connection. Southeastern United States. METHODS: FES-LEC three sessions per week for 12 months in participant's home and monitored by the research staff via internet connection. Pre- and post-exercise program testing for body composition including percent body fat, fat mass (FM), lean mass (LM) and whole-body bone mineral density (BMD) via dual-energy x-ray absorptiometry (DXA). RESULTS: There was a 7.7% increase in total body LM and a 4.1% increase in legs LM. There was a 1.2% decrease in total body FM and a 9.9% decrease in legs FM. Percent body fat decreased from 48.4 to 46.3 and whole-body BMD was increased from 0.934 to 1.023, which resulted in an improvement in the DXA T-score from -2.4 to -1.3. CONCLUSION: Positive body compositional changes during this study support the idea that long-term FES-LEC can help restore healthier ratios of LM and FM and possibly decrease the risk of associated diseases. Increased whole-body BMD provides hope that long-term FES-LEC may be beneficial regarding bone health.

Feasibility of home-based functional electrical stimulation cycling: case report.

STUDY DESIGN: Single-subject (male, 64 years of age) case. OBJECTIVES: To determine the feasibility of a home-based FES-LEC (functional electrical stimulation lower extremities cycling) program and effects on body composition, quality of life (QOL) and seat pressure mapping in an older individual with spinal cord injured (SCI). SETTING: Home-based FES-LEC with internet connection. Southeastern United States. METHODS: FES-LEC three sessions per week for 9 weeks in the participant's home and monitored by the research staff via internet connection. Pre- and post-exercise program testing of seat pressure mapping, QOL and body composition including percent body fat (%BF), fat mass (FM), lean mass (LM) and bone mineral density (BMD). RESULTS: The participant completed 25 of 27 recommended exercise sessions over 9 weeks for a 93% compliance rate. Cycling distance increased from 3.98 to 9.00 km (126%). Total body LM increased from 48.94 to 53.02 kg (8.3%). The %BF decreased from 29.6 to 28.4(-1.2%). Total body weight, FM and BMD remained unchanged. Average static seat pressure decreased from 55.5 to 52.59 mm Hg (5%), whereas maximum seat pressure decreased from 120.76 to 91.5 mm Hg (24%). The psychological domain (perception of body image, appearance and self-esteem) of the QOL questionnaire improved from 12.67 to 14. CONCLUSION: Positive changes in this study regarding body composition, QOL and seat pressure mapping support results of clinical studies using FES-LEC training on younger adults with SCI. The high percentage of exercise adherence and positive results on body composition, QOL and seat pressure provide support for the feasibility of home-based FES-LEC.

The effects of spinal cord injury and exercise on bone mass: a literature review.

INTRODUCTION: Bone loss is a common and often debilitating condition that accompanies spinal cord injury. Because bone loss after spinal cord injury is multifactorial, it can be difficult to assess and treat. This process becomes even more complex as secondary conditions associated with aging are introduced. PURPOSE: There are two purposes of this literature review. The first is to summarize information concerning the mechanisms of bone loss and osteoporosis after spinal cord injury. The second is to summarize existing data concerning the effects of exercise on bone loss after spinal cord injury. METHOD: Literature was reviewed concerning the bone loss process and the non-pharmacological treatment options for ameliorating bone loss after spinal cord injury. RESULTS: (Part One) Osteoporosis is universal in persons with chronic complete spinal cord injury, which increases the risk of bone fracture. Bone loss after spinal cord injury is both sublesional and regional with the greatest areas of bone demineralization being in the sublesional trabecular laden areas of the distal and proximal epiphyses of the femur and tibia. (Part Two) While passive weight bearing of paralyzed lower extremities appears to be ineffective, stressing the bones through muscular contractions initiated by electrical stimulation (FES) have yielded positive results in some cases. The intensity, frequency, and duration of stress to the bones appear to be important determinants of improved bone parameters. Although further quantification of these components is needed, some generalized guidelines can be deduced from completed research. Intensities showing positive results have been loads of one to one and a half times body weight for FES exercise or having participants FES cycle at their highest power output. Safety precautions must be used to decrease risk of bone fracture. Generally, the frequency is effective with three or more weekly exercise sessions. Studies of duration suggest that several months to one or more years of FES are necessary. DISCUSSION: In order to promote healthy and independent aging in patients with spinal cord injury, it is important to understand the processes, consequences and effective treatments involved with bone loss.

Oral baclofen administration in persons with chronic spinal cord injury does not prevent the protective effects of spasticity on body composition and glucose homeostasis.

STUDY DESIGN: Correlation study. OBJECTIVES: To determine the effects of oral baclofen on body composition (fat mass (FM), fat-free mass (FFM)), extra- and intracellular fluid compartments and glucose homeostasis (plasma glucose and plasma insulin concentrations) in individuals with spinal cord injury (SCI) after controlling for spasticity. SETTINGS: Laboratory settings at the University of Michigan, MI, USA. METHODS: Fifteen individuals with chronic motor complete SCI (32+/-8 years old, 25+/-5 kg/m(2), C6-T11, American Spinal Injury Association A and B) underwent multifrequency bioelectrical impedance analysis to measure body composition and body fluid compartments. Spasticity of the hip, knee and ankle flexors and extensors was measured using a modified Ashworth Scale and the dose of daily oral baclofen was recorded. After overnight fasting, plasma glucose and insulin sensitivity were measured in response to an oral glucose tolerance test. RESULTS: Oral baclofen dose was positively related to body mass index, but not to extensor or flexor spasticity. The dose of baclofen seemed to be correlated to extensor spasticity after considering spasticity per FFM. The increased dose of oral baclofen was positively associated with increased FFM, extra- and intracellular fluid compartments and total body water, but not with FM. Oral baclofen dose was negatively associated with the homeostatic model assessment index. CONCLUSION: Administration of oral baclofen did not attenuate the protective effects of spasticity on body composition and metabolic profile after SCI. The possibility that oral baclofen could exert an independent protective effect needs to be further investigated.

Spasticity may defend skeletal muscle size and composition after incomplete spinal cord injury.

DESIGN: Cross-sectional. OBJECTIVES: (1) To determine the effects of the level of spinal cord injury (SCI) on skeletal muscle, intramuscular fat (IMF) cross-sectional areas (CSAs) and relative IMF; (2) to determine the relation, if any, of spasticity to each of these variables after incomplete SCI. SETTINGS: In-patient study at the Shepherd Center, Atlanta, GA, USA. METHODS: Thirteen individuals with incomplete SCI were classified according to their level of injury into a high level of injury group (HLI, C5-C7, n=8) and a low level of injury group (LLI, T12-L2, n=5). Spasticity was determined for thigh muscles using a modified Ashworth scale at 6 weeks post-injury. T1-weighted magnetic resonance (MR) images were taken 6 weeks post-injury to measure thigh skeletal muscle and IMF CSAs. RESULTS: Spasticity was significantly evident in the HLI group compared to the LLI group (P=0.023). Six weeks post-injury, muscle CSA was 103+/-18 cm(2) in the HLI group and 80+/-20 cm(2) in the LLI group (P=0.042). Relative IMF was 3.6+/-2.0% in HLI and 7.5+/-4.0% in LLI (P=0.021). Additionally, spasticity accounted for 54% of the variability in muscle CSA for all subjects (r (2)=0.54, P=0.006). CONCLUSIONS: Spasticity may be an important factor in defending skeletal muscle size and indirectly preventing IMF accumulation early after incomplete SCI.

Skeletal muscle atrophy and increased intramuscular fat after incomplete spinal cord injury.

STUDY DESIGN: Cross-sectional and longitudinal design. OBJECTIVES: (1) To quantify skeletal muscle cross-sectional area (CSA) after correcting for intramuscular fat (IMF) in thigh muscle groups 6 weeks after incomplete spinal cord injury (SCI), (2) to monitor the changes in muscle CSA and IMF after 3 months from the initial measurement. SETTING: Academic institution Athens, GA, USA. METHODS: Six incomplete SCI patients (28+/-4 years, 178+/-5 cm and 78+/-6 kg, mean+/-SE, C7 to L3, American Spinal Injury Association B or C) were tested at 5+/-1 weeks and 3 months after the initial measurement. T1-weighted magnetic resonance images were taken of both thighs. Six able-bodied (AB) controls were matched in age, sex, height and weight (29+/-4 years, four male and two female subjects, 179+/-5 cm and 77+/-6 kg). RESULTS: At 6 weeks post-injury, muscle CSA was 82+/-4 cm(2) in incomplete SCI and 123+/-21 cm(2) in AB controls (P=0.04). IMF CSA was 5.2+/-1.3 and 2.3+/-0.6 cm(2) in incomplete SCI and AB controls, respectively (P=0.03). Relative IMF was three-fold higher (P=0.03) in the SCI group versus AB controls (5.8+/-1.4 versus 2.0+/-0.6%). After 3 months, IMF increased 26% in the SCI group compared to the initial measurement (P=0.02). CONCLUSIONS: Skeletal muscle atrophy is associated with greater IMF accumulation in SCI group 6 weeks post-injury compared to AB controls. Moreover, IMF continues to increase over time in incomplete SCI.

The advent of DNA databanks: implications for information privacy.

Genetic identification tests -- better known as DNA profiling -- currently allow criminal investigators to connect suspects to physical samples retrieved from a victim or the scene of a crime. A controversial yet acclaimed expansion of DNA analysis is the creation of a massive databank of genetic codes. This Note explores the privacy concerns arising out of the collection and retention of extremely personal information in a central database. The potential for unauthorized access by those not investigating a particular crime compels the implementation of national standards and stringent security measures.