Intact sympathetic nervous system is required for leptin effects on resting metabolic rate in people with spinal cord injury

Reasons for meal termination, eating frequency, and typical meal context differ between persons with and without a spinal cord injury

Overeating associated with neurogenic obesity after spinal cord injury (SCI) may be related to how persons with SCI experience satiation (processes leading to meal termination), their eating frequency, and the context in which they eat their meals. In an online, cross-sectional study, adults with (n = 688) and without (Controls; n = 420) SCI completed the Reasons Individuals Stop Eating Questionnaire-15 (RISE-Q-15), which measures individual differences in the experience of factors contributing to meal termination on five scales: Physical Satisfaction, Planned Amount, Decreased Food Appeal, Self-Consciousness, and Decreased Priority of Eating. Participants also reported weekly meal and snack frequency and who prepares, serves, and eats dinner with them at a typical dinner meal. Analysis revealed that while Physical Satisfaction, Planned Amount, and Decreased Food Appeal were reported as the most frequent drivers of meal termination in both groups, scores for the RISE-Q-15 scales differed across the groups. Compared to Controls, persons with SCI reported Physical Satisfaction and Planned Amount as drivers of meal termination less frequently, and Decreased Food Appeal and Decreased Priority of Eating more frequently (all p < 0.001). This suggests that persons with SCI rely less on physiological satiation cues for meal termination than Controls and instead rely more on hedonic cues. Compared to Controls, persons with SCI less frequently reported preparing and serving dinner meals and less frequently reported eating alone (all p < 0.001), indicating differences in meal contexts between groups. Individuals with SCI reported consuming fewer meals than Controls but reported a higher overall eating frequency due to increased snacking (p ≤ 0.015). A decrease in the experience of physical fullness, along with a dependence on a communal meal context and frequent snacking, likely contribute to overeating associated with neurogenic obesity after SCI.

Assessing the efficacy of duration and intensity prescription for physical activity in mitigating cardiometabolic risk after spinal cord injury

PURPOSE OF REVIEW

Spinal cord injury (SCI) heightens susceptibility to cardiometabolic risk (CMR), predisposing individuals to cardiovascular disease. This monograph aims to assess the optimal duration and intensity of physical activity (PA) for managing CMR factors, particularly obesity, after SCI and provide modality-specific PA durations for optimal energy expenditure.

RECENT FINDINGS

PA guidelines recommend at least 150 min/week of moderate-intensity activity. However, non-SCI literature supports the effectiveness of engaging in vigorous-intensity PA (≥6 METs) and dedicating 250-300 min/week (≈2000 kcal/week) to reduce CMR factors. Engaging in this volume of PA has shown a dose-response relationship, wherein increased activity results in decreased obesity and other CMR factors in persons without SCI.

SUMMARY

To optimize cardiometabolic health, individuals with SCI require a longer duration and higher intensity of PA to achieve energy expenditures comparable to individuals without SCI. Therefore, individuals with SCI who can engage in or approach vigorous-intensity PA should prioritize doing so for at least 150 min/wk. At the same time, those unable to reach such intensities should engage in at least 250-300 min/week of PA at a challenging yet comfortable intensity, aiming to achieve an optimal intensity level based on their abilities. Given the potential to decrease CMR after SCI, increasing PA duration and intensity merits careful consideration in future SCI PA directives.

Trends in measuring BMR and RMR after spinal cord injury: a comprehensive review

Studying factors that contribute to our understanding of maintaining normal energy balance are of paramount significance following spinal cord injury (SCI). Accurate determination of energy needs is crucial for providing nutritional guidance and managing the increasing prevalence of malnutrition or obesity after SCI. BMR represents 75-80 % of the total energy expenditure in persons with SCI. Accurately measuring BMR is an important component for calculating total energetic needs in this population. Indirect calorimetry is considered the gold-standard technique for measuring BMR. However, technical challenges may limit its applications in large cohort studies and alternatively rely on prediction equations. Previous work has shown that BMR changes in response to disuse and exercise in the range of 15-120 %. Factors including sex, level of injury and type of assistive devices may influence BMR after SCI. RMR is erroneously used interchangeably for BMR, which may result in overestimation of energetic intake when developing nutritional plans. To address this concern, we comprehensively reviewed studies that conducted BMR (n=15) and RMR (n=22) in persons with SCI. The results indicated that RMR is 9 % greater than BMR in persons with SCI. Furthermore, the SCI-specific prediction equations that incorporated measures of fat-free mass appeared to accurately predict BMR. Overall, the current findings highlighted the significance of measuring BMR as well as encouraging the research and clinical community to effectively establish countermeasures to combat obesity after SCI.

Unripe fruits of Litchi chinensis (Gaertn.) Sonn.: An overview of its toxicity

Litchi (Litchi chinensis) is a widely consumed fruit that has been used in many food and health-promoting products worldwide. Litchi is a good source of nutrients including vitamin and minerals, dietary fibers, proteins, and carbohydrates. Of note, several studies have reported that the constituents of litchi fruits elicit antioxidant properties and help to maintain blood pressure, and reduce the risk of stroke and heart attack. An unclearly explained outbreak occurred in June 2019 in Muzaffarpur (Bihar), India resulted in the death of more than 150 children in a week, followed by a total of 872 cases and 176 deaths. This outbreak was associated with the consumption of Litchi fruits and the occurrence of acute encephalitis syndrome. In this high Litchi production region, a huge number of acute encephalitis syndrome cases have been registered in children in the past two decades with high mortality due to these neurological disorders linked to the consumption of litchi. While finding out the causes for this recurrent outbreak, whether or not it is caused by a virus or the phytotoxins of litchi is to be considered critical. Amongst the probable causes were observed to be methylene cyclopropyl acetic acid and hypoglycin-A found in unripe Litchi fruits which can cause hypoglycemia and as a plausible cause of AES outbreaks. This review addresses this recurrent outbreak in-depth exploring the possible causes and discusses the possible mechanisms by which phytotoxins of litchi such as hypoglycin A and methylene cyclopropylglycine which may elicit such toxic effects.

A systematic review of cardiovascular risk factors in patients with traumatic spinal cord injury

Objective: The main risk factors for cardiac events, and particularly for the development of atherosclerosis, are diabetes mellitus, arterial hypertension, dyslipidemia and smoking. Patients with a traumatic spinal cord injury (SCI) may present with autonomic nervous system dysfunction depending on their level of spinal cord injury. Studies have found a rise in cardiovascular mortality. A systematic review was conducted that focused on this patient group's predisposition to vascular risk. Methods: We performed a PubMed and Cochrane database search. After applying specific search criteria, 42 articles were included in our analysis out of a total of 10,784 matches. The articles were selected with the aim of establishing cardiovascular risk factors in patients with traumatic spinal cord injury. Results: Patients with SCI are at an increased risk for peripheral artery disease even in the absence of cardiovascular risk factors. Major vascular changes to the arteries of patients with SCI include: a reduction in lumen size, increased vessel wall tension, higher vascular stiffness, an impaired reactive hyperemic response, and a lack of reduced vascular resistance. The findings for carotid atherosclerosis were inconclusive. This group of patients also has a higher disposition for diabetes mellitus, lipid metabolism disorders and coronary artery disease. Paraplegics are more likely to suffer from dyslipidemia, obesity and PAD, while tetraplegics are more likely to have diabetes mellitus. Conclusions: Patients with SCI are more likely to have cardiovascular risk factors and have cardiovascular disease compared to the normal population. Peripheral circulatory disorders are particularly common. Patients with SCI are now considered to be a new risk group for cardiovascular disease; however, large epidemiological studies are needed to verify in more detail the cardiovascular risk profile of this patient group.

Research and prospect of peptides for use in obesity treatment (Review)

Obesity and its related diseases, such as type 2 diabetes, hypertension and cardiovascular disease, are steadily increasing worldwide. Over the past few decades, numerous studies have focused on the differentiation and function of brown and beige fat, providing evidence for their therapeutic potential in treating obesity. However, no specific novel drug has been developed to treat obesity in this way. Peptides are a class of chemically active substances, which are linked together by amino acids using peptide bonds. They have specific physiological activities, including browning of white fat. As signal molecules regulated by the neuroendocrine system, the role of polypeptides, such as neuropeptide Y, brain-gut peptide and glucagon-like peptide in obesity and its related complications has been revealed. Notably, with the rapid development of peptidomics, peptide drugs have been widely used in the prevention and treatment of metabolic diseases, due to their short half-life, small apparent distribution volume, low toxicity and low side effects. The present review summarizes the progress and the new trend of peptide research, which may provide novel targets for the prevention and treatment of obesity.

New Frontiers for the Use of IP6 and Inositol Combination in Treating Diabetes Mellitus: A Review

Inositol, or myo-inositol, and associated analog molecules, including myo-inositol hexakisphosphate, are known to possess beneficial biomedical properties and are now being widely studied. The impact of these compounds in improving diabetic indices is significant, especially in light of the high cost of treating diabetes mellitus and associated disorders globally. It is theorized that, within ten years, the global population of people with the disease will reach 578 million individuals, with the cost of care projected to be approximately 2.5 trillion dollars. Natural alternatives to pharmaceuticals are being sought, and this has led to studies involving inositol, and myo-inositol-hexakisphosphate, also referred to as IP6. It has been reported that IP6 can improve diabetic indices and regulate the activities of some metabolic enzymes involved in lipid and carbohydrate metabolism. Current research activities have been focusing on the mechanisms of action of inositol and IP6 in the amelioration of the indices of diabetes mellitus. We demonstrated that an IP6 and inositol combination supplement may regulate insulin secretion, modulate serum leptin concentrations, food intake, and associated weight gain, which may be beneficial in both prediabetic and diabetic states. The supplement attenuates vascular damage by reducing red cell distribution width. Serum HDL is increased while serum triglycerides tend to decrease with consumption of the combination supplement, perhaps due to the modulation of lipogenesis involving reduced serum lipase activity. We also noted increased fecal lipid output following combination supplement consumption. Importantly, liver function was found to be preserved. Concurrently, serum reactive oxygen species production was reduced, indicating that inositol and IP6 supplement consumption may reduce free radical damage to tissues and organs as well as serum lipids and blood glucose by preserving liver function. This review provides an overview of the findings associated with inositol and IP6 supplementation in the effective treatment of diabetes with a view to proposing the potential mechanisms of action.

The pathogenesis of obesity

Body fat mass increases when energy intake exceeds energy expenditure. In the long term, a positive energy balance will result in obesity. The worldwide prevalence of obesity has increased dramatically, posing a serious threat to human health. Therefore, insight in the pathogenesis of obesity is important to identify novel prevention and treatment strategies. This review describes the physiology of energy expenditure and energy intake in the context of body weight gain in humans. We focus on the components of energy expenditure and the regulation of energy intake. Finally, we describe rare monogenetic causes leading to an impairment in central regulation of food intake and obesity.

Energy Expenditure as a Function of Activity Level After Spinal Cord Injury: The Need for Tetraplegia-Specific Energy Balance Guidelines

The World Health Organization recognizes obesity as a global and increasing problem for the general population. Because of their reduced physical functioning, people with spinal cord injury (SCI) face additional challenges for maintaining an appropriate whole body energy balance, and the majority with SCI are overweight or obese. SCI also reduces exercise capacity, particularly in those with higher-level injury (tetraplegia). Tetraplegia-specific caloric energy expenditure (EE) data is scarce. Therefore, we measured resting and exercise-based energy expenditure in participants with tetraplegia and explored the accuracy of general population-based energy use predictors. Body composition and resting energy expenditure (REE) were measured in 25 adults with tetraplegia (C4/5 to C8) and in a sex-age-height matched group. Oxygen uptake, carbon dioxide production, heart rate, perceived exertion, and exercise intensity were also measured in 125 steady state exercise trials. Those with motor-complete tetraplegia, but not controls, had measured REE lower than predicted (mean = 22% less, p < 0.0001). REE was also lower than controls when expressed per kilogram of lean mass. Nine had REE below 1200 kcal/day. We developed a graphic compendium of steady state EE during arm ergometry, wheeling, and hand-cycling. This compendium is in a format that can be used by persons with tetraplegia for exercise prescription (calories, at known absolute intensities). EE was low (55–450 kcal/h) at the intensities participants with tetraplegia were capable of maintaining. If people with tetraplegia followed SCI-specific activity guidelines (220 min/week) at the median intensities we measured, they would expend 563–1031 kcal/week. Participants with tetraplegia would therefore require significant time (4 to over 20 h) to meet a weekly 2000 kcal exercise target. We estimated total daily EE for a range of activity levels in tetraplegia and compared them to predicted values for the general population. Our analysis indicated that the EE values for sedentary through moderate levels of activity in tetraplegia fall well below predicted sedentary levels of activity for the general population. These findings help explain sub-optimal responses to exercise interventions after tetraplegia, and support the need to develop tetraplegia-specific energy-balance guidelines that reflects their unique EE situation.

Nutritional Health Considerations for Persons with Spinal Cord Injury

Chronic spinal cord injury (SCI) often results in morbidity and mortality due to all-cause cardiovascular disease (CVD) and comorbid endocrine disorders. Several component risk factors for CVD, described as the cardiometabolic syndrome (CMS), are prevalent in SCI, with the individual risks of obesity and insulin resistance known to advance the disease prognosis to a greater extent than other established risks. Notably, adiposity and insulin resistance are attributed in large part to a commonly observed maladaptive dietary/nutritional profile. Although there are no evidence-based nutritional guidelines to address the CMS risk in SCI, contemporary treatment strategies advocate more comprehensive lifestyle management that includes sustained nutritional guidance as a necessary component for overall health management. This monograph describes factors in SCI that contribute to CMS risks, the current nutritional profile and its contribution to CMS risks, and effective treatment strategies including the adaptability of the Diabetes Prevention Program (DPP) to SCI. Establishing appropriate nutritional guidelines and recommendations will play an important role in addressing the CMS risks in SCI and preserving optimal long-term health.

Level-Specific Differences in Systemic Expression of Pro- and Anti-Inflammatory Cytokines and Chemokines after Spinal Cord Injury

While over half of all spinal cord injuries (SCIs) occur in the cervical region, the majority of preclinical studies have focused on models of thoracic injury. However, these two levels are anatomically distinct—with the cervical region possessing a greater vascular supply, grey-white matter ratio and sympathetic outflow relative to the thoracic region. As such, there exists a significant knowledge gap in the secondary pathology at these levels following SCI. In this study, we characterized the systemic plasma markers of inflammation over time (1, 3, 7, 14, 56 days post-SCI) after moderate-severe, clip-compression cervical and thoracic SCI in a rat model. Using high-throughput ELISA panels, we observed a clear level-specific difference in plasma levels of VEGF, leptin, IP10, IL18, GCSF, and fractalkine. Overall, cervical SCI had reduced expression of both pro- and anti-inflammatory proteins relative to thoracic SCI, likely due to sympathetic dysregulation associated with higher level SCIs. However, contrary to the literature, we did not observe level-dependent splenic atrophy with our incomplete SCI model. This is the first study to compare the systemic plasma-level changes following cervical and thoracic SCI using level-matched and time-matched controls. The results of this study provide the first evidence in support of level-targeted intervention and also challenge the phenomenon of high SCI-induced splenic atrophy in incomplete SCI models.

Associations between lean mass and leptin in men with chronic spinal cord injury: Results from the FRASCI-muscle study

Leptin is an adipo-myokine that regulates appetite and energy expenditure by a neuroendocrine feedback loop. Leptin levels are positively correlated with BMI in the spinal cord injury population and leptin levels are greater in individuals with spinal cord injury compared to uninjured controls. Leptin is produced in multiple tissues, including fat, bone, and skeletal muscle and is a putative biomarker of sedentary behavior in older adults. We assessed body composition leptin, adiponectin, and IL-6 levels in 205 men with chronic spinal cord injury. We found no association between age, injury duration, injury level, injury completeness, or walking status and leptin. There was a significant positive association between lean mass and leptin in men with SCI that was independent of fat. Adjusting for body composition, leptin levels were positively associated with IL-6 and negatively associated with adiponectin levels. When considering men with SCI and sarcopenic obesity, only fat mass remained positively associated with leptin. We found no association between IL-6, adiponectin, or lean mass and leptin in the sarcopenic obesity group. Our findings suggest that lean mass is an under recognized, but substantial, source of circulating leptin. Furthermore, SCI-related sarcopenic obesity may result in dysregulated adipo-myokine metabolism with local and systemic physiologic effects.

Resting energy expenditure in male athletes with a spinal cord injury

OBJECTIVE

To investigate whether there are differences in the resting energy expenditure (REE) and body composition of athletes with a spinal cord injury (SCI) compared to active able-bodied controls.

DESIGN

In this cross sectional study, male athletes with a SCI were compared to active able-bodied controls matched for age, stretch stature and body mass. In addition, the accuracy of standard REE prediction equations in estimating REE was assessed.

PARTICIPANTS

Seven male wheelchair athletes with a SCI and six matched active able-bodied controls volunteered to participate.

OUTCOME MEASURES

REE was measured using indirect calorimetry and estimated using population-specific prediction equations. Body composition (lean tissue mass, fat mass and bone mineral content) was measured by dual energy X-ray absorptiometry (DXA).

RESULTS

While absolute and adjusted REE in the athletes with SCI was lower than controls, this difference was not significant (P = 0.259). When adjusted for lean tissue mass (LTM), REE was significantly higher (P = 0.038) in the athletes with SCI compared to the controls (146 ± 29kJ/kg LTM vs. 125 ± 8kJ/kg LTM). LTM was significantly lower in the athletes with SCI (44.35 ± 6.98 kg) compared to the able-bodied controls (56.02 ± 4.93 kg; P < 0.01). The differences between predicted and measured REE in the athletes with SCI were not statistically significant (except for the Owen equation), however there was no significant correlation between the measures.

CONCLUSION

This suggests that existing prediction equations used to estimate energy requirements may require modification for athletes with SCI.

Feasibility and Acceptability of Implementing Indirect Calorimetry Into Routine Clinical Care of Patients With Spinal Cord Injury

Background: In the absence of reliable predictive equations, indirect calorimetry (IC) remains the gold standard for assessing energy requirements after spinal cord injury (SCI), but it is typically confined to a research setting. The purpose of this study is to assess the feasibility and acceptability of implementing IC into routine clinical care in an Australian SCI rehabilitation facility. Methods: Bedside IC (canopy hood) was performed, and patients completed an IC acceptability questionnaire (open-ended; yes/no; 5-point Likert scale). Fasted resting energy expenditure (REE) steady-state criteria were applied to assess data quality, and adherence to a test ≥20 minutes was recorded. Staff were surveyed to assess impact of IC on usual care. Results: Of 35 eligible patients, 9 declined (7 reported claustrophobia). One patient could not be tested before discharge and 25 underwent IC (84% male, injury level C2-L2, AIS A-D). Anxiety prevented one patient from completing IC, while another failed to fast. The remaining 23 patients achieved a steady-state REE (≥5 consecutive minutes with ≤10% coefficient of variation for VO₂ and VCO₂). Test-retest (n = 5) showed <10% variation in REE. Patients deemed the procedure acceptable, with 88% reporting a willingness to repeat IC. Eighty percent of patients and 90% of staff agreed it was acceptable for IC to be integrated into usual care. Conclusion: This study found that IC is a feasible and acceptable addition to the routine clinical care of patients recovering from SCI and may serve to improve accuracy of nutrition interventions for this patient population.

The hyperleptinemia state can downregulate cardiorespiratory fitness and energy expenditure in obese women

INTRODUCTION

In general, in obese people a state of hyperleptinemia may impair both energy balance and the inflammatory process. However, it has not been fully investigated whether there is a relationship between hyperleptinemia and cardiorespiratory fitness (CRF) and resting energy expenditure (REE), in obese women.

METHODS

83 obese women were enrolled in this cross-sectional study. Anthropometric measures, body composition, REE, CRF and serum concentration of leptin were measured. Pearson's correlation coefficient was performed to examine the relationship between circulating leptin level and other clinical variables. Multiple regression analysis was applied to determine predictors of REE and CRF. Effects were considered significant at p≤0.05.

RESULTS

The most important finding in the present study is that the hyperleptinemia state was inversely correlated with CRF (r=-0.382, p=0.001) and REE (r=-0.447, p<0.001). Moreover, a positive correlation with fat mass was confirmed (r=0.419, p<0.001). In addition, hyperleptinemia was an independent negative predictor of REE (r²=-2.649, p=0.010) and CRF (r²=-2.335, p=0.023).

CONCLUSION

Together our results may suggest a vicious cycle between the state of hyperleptinemia and a decrease in energy expenditure and cardiorespiratory fitness in obese women, which can impair whole body energy homeostasis. This information is important to contribute to clinical practices.

A lifestyle intervention program for successfully addressing major cardiometabolic risks in persons with SCI: a three-subject case series

INTRODUCTION

This study is a prospective case series analyzing the effects of a comprehensive lifestyle intervention program in three patients with chronic paraplegia having major risks for the cardiometabolic syndrome (CMS).

CASE PRESENTATION

Individuals underwent an intense 6-month program of circuit resistance exercise, nutrition using a Mediterranean diet and behavioral support, followed by a 6-month extension (maintenance) phase involving minimal support. The primary goal was a 7% reduction of body mass. Other outcomes analyzed insulin resistance using the HOMA-IR model, and plasma levels of fasting triglycerides and high-density lipoprotein cholesterol. All participants achieved the goal for 7% reduction of body mass and maintained the loss after the MP. Improvements were observed in 2/3 subjects for HOMA-IR and high-density lipoprotein cholesterol. All participants improved their risk for plasma triglycerides.

DISCUSSION

We conclude, in a three-person case series of persons with chronic paraplegia, a lifestyle intervention program involving circuit resistance training, a calorie-restrictive Mediterranean-style diet and behavioral support, results in clinically significant loss of body mass and effectively reduced component risks for CMS and diabetes. These results were for the most part maintained after a 6-month MP involving minimal supervision.

The effect of combined inositol hexakisphosphate and inositol supplement in streptozotocin-induced type 2 diabetic rats

Inositol hexakisphosphate (IP6) and inositol both regulate insulin secretion, but their combined use in the management of diabetes deserves investigation. The combined effects of IP6 and inositol supplementation were investigated in streptozotocin-induced type 2 diabetic rats. The following groups of rats were studied for 8 weeks: non-diabetic control, non-diabetic high-fat diet control, diabetic untreated, diabetic rats treated with the combination of IP6 and inositol (650 mg/kg bw) and diabetic rats treated with glibenclamide (10 mg/kg bw). High-fat diet and streptozotocin were used to induce type 2 diabetes mellitus in Sprague-Dawley rats. Body weight, blood glucose, glycated haemoglobin, insulin, serum leptin, HOMA-insulin resistance scores, intestinal amylase activity, serum and faecal lipids and food and fluid consumption were measured. Treatment with the combination significantly reduced blood glucose (306 ± 53 mg/dl) and insulin resistance score (1.93 ± 0.45) compared with diabetic controls (522 ± 24 mg/dl and 5.1 ± 0.69 respectively). Serum leptin (2.8 ± 0.6 ng/dl) and faecal triglycerides (108 ± 8 mg/dl) were significantly increased in rats treated with the combination compared with the diabetic control (1.8 ± 0.06 ng/dl and 86 ± 4 mg/dl). Serum triglyceride (47 ± 5.1 mg/dl), total cholesterol (98 ± 3.2 mg/dl) and food intake (26 ± 0.3 g) were significantly reduced by 45%, 25% and 25%, respectively, in rats treated with the combination compared with the diabetic control. Inositol and IP6 combined supplementation may be effective in the management of type 2 diabetes mellitus and related metabolic disorders by regulating some aspects of lipid and carbohydrate metabolism.

Contributors to Metabolic Disease Risk Following Spinal Cord Injury

Spinal cord injury (SCI) induced changes in neurological function have significant impact on the metabolism and subsequent metabolic-related disease risk in injured individuals. This metabolic-related disease risk relationship is differential depending on the anatomic level and severity of the injury, with high level anatomic injuries contributing a greater risk of glucose and lipid dysregulation resulting in type 2 diabetes and cardiovascular disease risk elevation. Although alterations in body composition, particularly excess adiposity and its anatomical distribution in the visceral depot or ectopic location in non-adipose organs, is known to significantly contribute to metabolic disease risk, changes in fat mass and fat-free mass do not fully account for this elevated disease risk in subjects with SCI. There are other negative adaptations in body composition including reductions in skeletal muscle mass and alterations in muscle fiber type, in addition to significant reduction in physical activity, that contribute to a decline in metabolic rate and increased metabolic disease risk following SCI. Recent studies in adult humans suggest cold- and diet-induced thermogenesis through brown adipose tissue metabolism may be important for energy balance and substrate metabolism, and particularly sensitive to sympathetic nervous signaling. Considering the alterations that occur in the autonomic nervous system (SNS) (sympathetic and parasympathetic) following a SCI, significant dysfunction of brown adipose function is expected. This review will highlight metabolic alterations following SCI and integrate findings from brown adipose tissue studies as potential new areas of research to pursue.

The effect of autonomic nervous system dysfunction on oxygen consumption during daily living activities in patients with spinal cord injury

STUDY DESIGN

Case-control study.

OBJECTIVES

To investigate the level of autonomic nervous system dysfunction in patients with spinal cord injury and to determine its effect on the basal metabolic rate and oxygen consumption during daily living activities.

SETTING

Turkish Armed Forces Rehabilitation Center, Ankara, Turkey.

METHODS

Thirty-six patients with chronic spinal cord injury (SCI) were allocated into two groups according to the presence of autonomic nervous system dysfunction. Autonomic nervous system dysfunction was investigated with the measurements of blood pressure and heart rate during urodynamic examination and several provocative maneuvers (standing at tilt table, forcing deep respiration and Valsalva). Groups were compared in terms of the basal metabolic rate and oxygen consumption during daily living activities. Measurement of the basal metabolic rate was determined by indirect calorimetry under standardized conditions. Total body fat mass and lean tissue mass were measured in all participants using dual-energy X-ray absorptiometry by standard methods. Telemetric intrapulmonary gas exchange analyzer was used to measure oxygen consumption during daily living activities.

RESULTS

There was no statistically significant difference between the groups in age, time since injury, body mass lean and fat rates, or sensory and motor scores (P>0.05). Basal metabolic rates and oxygen consumption during daily living activities were not different between the groups (P>0.05).

CONCLUSIONS

These results suggest that the presence of autonomic dysfunction does not change oxygen consumption at rest and during daily living activities.

Investigation of measured and predicted resting energy needs in adults after spinal cord injury: a systematic review

BACKGROUND

Accurate estimation of energy needs is vital for effective nutritional management of individuals with spinal cord injury (SCI). Inappropriate energy prescription after SCI can compound the rates of malnutrition or obesity, increase the risk of complications and negatively influence outcomes. Energy requirements following SCI are not well understood, and there is currently no universally accepted method of estimating energy needs in clinical practice.

STUDY DESIGN

This is a systematic literature review.

OBJECTIVES

The objectives of this study were to investigate and compare the measured resting energy needs of adults with SCI across different phases of rehabilitation, and to identify appropriate energy prediction equations for use in SCI.

SETTING

This study was conducted in Australia.

METHODS

MEDLINE, EMBASE and CENTRAL databases were searched for studies published between 1975 and April 2015, identifying 298 articles. Full articles in English language of adults with SCI who were fasted for a minimum of 8 hours before undergoing indirect calorimetry to measure resting energy expenditure (REE) for at least 20 min were selected. On the basis of the inclusion criteria, 18 articles remained for data extraction. One author extracted information from all articles, and inter-rater reliability was tested in five articles.

RESULTS

REE across three phases of injury was assessed: acute, sub-acute and chronic. Few studies (n=2) have investigated REE in the acute and sub-acute injury stages of SCI recovery. The factors influencing chronic energy needs in SCI patient populations are many and varied, and a valid predictive equation for use in SCI remains elusive.

CONCLUSION

Indirect calorimetry remains the only accurate assessment of REE for health practitioners working with patients after SCI.

Serum lipid profile in subjects with traumatic spinal cord injury

Background and Aims

Few large studies have examined the relationship between spinal cord injury (SCI) and lipid profile. We studied serum lipid concentrations in subjects with traumatic SCI in relation to the degree of neurological involvement and time since injury, and compared them with values from a reference sample for the Spanish population (DRECE study).

Materials and Methods

A retrospective cohort was built from 177 consecutive cases with traumatic SCI admitted to the SCI unit of the Miguel Servet Hospital in Aragon (Spain). Outcome measures (cholesterol, triglycerides, HDL-c and LDL-c levels) were analyzed according to the ASIA Impairment Scale (AIS), neurological level of injury (involvement of all limbs vs. only lower limbs), and time since injury. All analyses were adjusted for age and sex.

Results

Cases without preserved motor function (AIS A or B) had lower total and HDL cholesterol than the others (-11.4 [-21.5, -1.4] mg/dL total cholesterol and -5.1 [-8.8, -1.4] mg/dL HDL-c), and cases with all-limb involvement had lower total, HDL, and LDL cholesterol than those with only lower-limb involvement (-14.0 [-24.6, -3.4] mg/dL total cholesterol, -4.1 [-8.0, -0.2] mg/dL HDL-c, and -10.0 [-19.7, -0.3] mg/dL LDL-c) (all p<0.05). No association was found between lipid concentrations and time since injury. Concentrations of lipid subfractions and triglycerides in SCI subjects were lower than in sex- and age-stratified values from the reference sample.

Conclusion

A high degree of neurological involvement in SCI (anatomically higher lesions and AIS A or B) is associated with lower total cholesterol and HDL-c.

Effects of spinal cord injury on body composition and metabolic profile - part I

Several body composition and metabolic-associated disorders such as glucose intolerance, insulin resistance, and lipid abnormalities occur prematurely after spinal cord injury (SCI) and at a higher prevalence compared to able-bodied populations. Within a few weeks to months of the injury, there is a significant decrease in total lean mass, particularly lower extremity muscle mass and an accompanying increase in fat mass. The infiltration of fat in intramuscular and visceral sites is associated with abnormal metabolic profiles. The current review will summarize the major changes in body composition and metabolic profiles that can lead to comorbidities such as type 2 diabetes mellitus and cardiovascular diseases after SCI. It is crucial for healthcare specialists to be aware of the magnitude of these changes. Such awareness may lead to earlier recognition and treatment of metabolic abnormalities that may reduce the co-morbidities seen over the lifetime of persons living with SCI.

Basal and resting metabolic rates of physically disabled adult subjects: a systematic review of controlled cross-sectional studies

AIM

To systematically review studies that investigated the basal metabolic rate (BMR) and resting metabolic rate (RMR) of physically disabled adult subjects.

METHODS

The studies were identified via MedLine, Science Direct, Science Search, Scientific Electronic Library Online, Wiley, Latin American and Caribbean Health Sciences Literature, Cochrane, Indice Bibliográfico Espanõl de Ciencias de la Salud, Scopus, ProQuest Dissertations & Theses Database and System for Information on Grey Literature in Europe. No restriction on publication date was imposed.

RESULTS

Data from 6 studies were included. The results showed that physically disabled adult subjects have a lower BMR and/or RMR compared to nondisabled subjects. However, the difference between the groups disappeared when the BMR and RMR were adjusted for fat-free mass. Due to the small number of studies on this subject and the limited types of physical disabilities evaluated in the literature, we could not make a definitive conclusion.

CONCLUSIONS

Disabled individuals seem to have a lower absolute BMR and/or RMR than able-bodied adults; however, this difference was not present or else it disappeared in half of the studies, after adjusting for body mass and/or fat-free mass.

Adiponectin is a candidate biomarker of lower extremity bone density in men with chronic spinal cord injury

Adipose tissue is a major regulator of bone metabolism and in the general population obesity is associated with greater bone mineral density (BMD). However, bone-fat interactions are multifactorial, and may involve pathways that influence both bone formation and resorption with competing effects on the skeleton. One such pathway involves adipocyte production of adipokines that regulate bone metabolism. In this study we determined the association between BMD, walking status, and circulating adipokines (adiponectin and leptin) in 149 men with chronic spinal cord injury (SCI). Although adipokine levels did not vary significantly based on walking status, there was a significant inverse association between adiponectin and BMD in wheelchair users independent of body composition. We found no association between adiponectin and BMD in the walkers and no association between leptin and BMD in either group. These findings suggest that for subjects with chronic SCI, walking may mitigate the effect of adiponectin mediated bone loss. For wheelchair users, adipose-derived adiponectin may contribute to SCI-induced osteoporosis because the osteoprotective benefits of obesity appear to require mechanical loading during ambulation.

Neuroendocrine and cardiac metabolic dysfunction and NLRP3 inflammasome activation in adipose tissue and pancreas following chronic spinal cord injury in the mouse

CVD (cardiovascular disease) represents a leading cause of mortality in chronic SCI (spinal cord injury). Several component risk factors are observed in SCI; however, the underlying mechanisms that contribute to these risks have not been defined. Central and peripheral chronic inflammation is associated with metabolic dysfunction and CVD, including adipokine regulation of neuroendocrine and cardiac function and inflammatory processes initiated by the innate immune response. We use female C57 Bl/6 mice to examine neuroendocrine, cardiac, adipose and pancreatic signaling related to inflammation and metabolic dysfunction in response to experimentally induced chronic SCI. Using immuno-histochemical, -precipitation, and -blotting analysis, we show decreased POMC (proopiomelanocortin) and increased NPY (neuropeptide-Y) expression in the hypothalamic ARC (arcuate nucleus) and PVN (paraventricular nucleus), 1-month post-SCI. Long-form leptin receptor (Ob-Rb), JAK2 (Janus kinase)/STAT3 (signal transducer and activator of transcription 3)/p38 and RhoA/ROCK (Rho-associated kinase) signaling is significantly increased in the heart tissue post-SCI, and we observe the formation and activation of the NLRP3 (NOD-like receptor family, pyrin domain containing 3) inflammasome in VAT (visceral adipose tissue) and pancreas post-SCI. These data demonstrate neuroendocrine signaling peptide alterations, associated with central inflammation and metabolic dysfunction post-SCI, and provide evidence for the peripheral activation of signaling mechanisms involved in cardiac, VAT and pancreatic inflammation and metabolic dysfunction post-SCI. Further understanding of biological mechanisms contributing to SCI-related inflammatory processes and metabolic dysfunction associated with CVD pathology may help to direct therapeutic and rehabilitation countermeasures.

Changes of leptin concentration in plasma in patients with spinal cord injury: a meta-analysis

OBJECTIVE

The aim of this study was to investigate changes of leptin concentration in plasma in patients with spinal cord injury to come to a single concept by using a Meta-analysis.

SETTING

Systematic Review.

METHODS

Searching relevant articles was performed in Ovid data base, Medline (PubMed) EMBASE, Google Scholar, Cochrane and Scopus up to February 2013. Five articles were selected using two independent reviewers. Analysis were performed using SPSS version 18 and Comparative Meta-analysis software version 2.0.

RESULTS

The combined analysis with confidence interval of 95% using comprehensive meta-analysis showed significant higher leptin levels in patients with spinal cord injury in comparison with able bodies (P<0.0001). The effect of spinal lesion level on plasma leptin concentration was also statistically significant (P<0.0001). Body mass index was positively related to plasma leptin concentration in both groups (P<0.0001).

CONCLUSION

This Meta analysis approves increased level of leptin in spinal cord injured patients which can be due to fat distribution changes and sympathetic dysfunction in these patients. Our results also showed that patients with higher spinal lesion level have higher plasma leptin concentration.

Spinal cord injury-induced osteoporosis: pathogenesis and emerging therapies

Spinal cord injury causes rapid, severe osteoporosis with increased fracture risk. Mechanical unloading after paralysis results in increased osteocyte expression of sclerostin, suppressed bone formation, and indirect stimulation of bone resorption. At this time, there are no clinical guidelines to prevent bone loss after SCI, and fractures are common. More research is required to define the pathophysiology and epidemiology of SCI-induced osteoporosis. This review summarizes emerging therapeutics including anti-sclerostin antibodies, mechanical loading of the lower extremity with electrical stimulation, and mechanical stimulation via vibration therapy.

Chronic sympathetic attenuation and energy metabolism in autonomic failure

The sympathetic nervous system regulates thermogenesis and energy homeostasis in humans. When activated it increases energy expenditure, particularly resting energy expenditure. Most human studies used acute infusion of β-blockers as a model to eliminate sympathetic stimulation and to examine the contribution of the sympathetic nervous system to energy metabolism and balance. Clinically, however, it is also important to assess the effect of chronic sympathetic attenuation on energy metabolism. In this context, we hypothesized that resting energy expenditure is decreased in patients with autonomic failure who, by definition, have low sympathetic tone. We measured 24-hour energy expenditure using whole-room indirect calorimeter in 10 adults with chronic autonomic failure (6 women; age, 64.9±9.1 years; body mass index, 25.2±4.4 kg/m(2)) and 15 sedentary healthy controls of similar age and body composition (8 women; age, 63.1±4.0 years; body mass index, 24.4±3.9 kg/m(2)). In 4 patients, we eliminated residual sympathetic activity with the ganglionic blocker trimethaphan. We found that, after adjusting for body composition, resting energy expenditure did not differ between patients with autonomic failure and healthy controls. However, resting energy expenditure significantly decreased when residual sympathetic activity was eliminated. Our findings suggest that sympathetic tonic support of resting energy expenditure is preserved, at least in part, in pathophysiological models of chronic sympathetic attenuation.

Comparison of methods to assess energy expenditure and physical activity in people with spinal cord injury

OBJECTIVE

To compare different methods of assessing energy expenditure (EE) and physical activity (PA) in people with spinal cord injury (SCI) under community-dwelling conditions.

METHODS

A reference standard encompassing the doubly labelled water (DLW) technique, heart rate monitoring (FLEX-HR), a multi-sensor armband (SenseWear Armband (SWA)), and two PA recall questionnaires were employed in 14 people with SCI to estimate EE and leisure-time PA.

RESULTS

Mean total daily energy expenditure (TDEE) assessed by DLW, FLEX-HR, and SWA were 9817 ± 2491 kJ/day, 8498 ± 1516 kJ/day, and 11414 ± 3242 kJ/day, respectively. Physical activity energy expenditure (PAEE) quantified by DLW was 2841 ± 1626 kJ/day, 2935 ± 1732 kJ/day estimated from FLEX-HR, and 2773 ± 2966 kJ/day derived from SWA. After converting the PA recall questionnaire data to EE in kJ/day, PAEE for the Physical Activity Recall Assessment for People with Spinal Cord Injury (PARA-SCI) was 2339 ± 1171 kJ/day and for Physical Activity Scale for Individuals with Physical Disabilities (PASIPD) 749 ± 1026 kJ/day. DLW-quantified PAEE was moderately associated with PARA-SCI (R(2) = 0.62, P < 0.05), but not with the other estimates of PAEE (R(2) ranged between 0.13 and 0.30, P > 0.05).

CONCLUSION

Our findings revealed that the PARA-SCI recall questionnaire was the best estimate of PAEE compared to the reference standard DLW approach. Although the between-method variability for SWA, FLEX-HR, and PASIPD-derived PAEE was small, there was a weak association between these methods and the criterion DLW technique. The best estimate of DLW-quantified TDEE was by FLEX-HR. SWA significantly overestimated TDEE in this population.

Overweight and obesity in women with physical disabilities: associations with demographic and disability characteristics and secondary conditions

BACKGROUND

This cross-sectional study was designed to examine weight in association with demographic and disability characteristics and secondary conditions in a sample of community living women with physical disabilities.

METHODS

443 predominantly ethnic minority women with physical disabilities were recruited through public and private health clinics and community organizations. They completed questionnaires including measures of body mass index and a health conditions checklist.

RESULTS

Data showed that nearly three-quarters of the sample were overweight (26.6%) or obese (47.6%) with 14% extremely obese. Obesity was highest among middle aged women (aged 45-54, 52.7%; aged 55-64, 52.5%; compared to aged 18-44, 37.8%; or aged ≥65, 39.1%). Black (84.0%) and Hispanic women (83.8%) were more likely to be overweight or obese compared to non-Hispanic white women (56.7%). Women with joint and connective tissue diseases and women with more extensive functional limitations were more likely to have excess weight. Disability factors were more strongly associated with excess weight than demographic factors other than age. Weight classification was significantly related to whether or not the women had ever had diabetes or blood pressure problems. Diabetes was reported 4 times as often as among women in general (36.3% versus 8.9%), and hypertension nearly twice as often (56.2% versus 30.9%).

CONCLUSIONS

These findings indicate extremely high rates of overweight and obesity in women with physical disabilities, a growing population greatly in need of effective weight management interventions. Overweight and obesity in combination with disability in women was associated with disproportionately high rates of diabetes and hypertension.

Energy cost of physical activities in persons with spinal cord injury

INTRODUCTION

The objectives of this descriptive study were (a) to determine the energy expenditure of activities commonly performed by individuals with a spinal cord injury (SCI) and summarize this information and (b) to measure resting energy expenditure and establish the value of 1 MET for individuals with SCI.

METHODS

One-hundred seventy adults with SCI were partitioned by gender, anatomical level of SCI, and American Spinal Injury Association designations for motor function. Twenty-seven physical activities, 12 recreational/sport and 15 daily living, were performed, while energy expenditure was measured continuously via a COSMED K4b portable metabolic system. In addition, 66 adult males with SCI completed 30 min of supine resting energy testing in a quiet environment.

RESULTS

Results for the 27 measured activities are reported in kilocalories per minute (kcal·min(-1)) and VO2 (mL·min(-1) and mL·kg(-1)·min(-1)). One MET for a person with SCI should be adjusted using 2.7 mL·kg(-1)·min(-1). Using 2.7 mL·kg(-1)·min(-1), the MET range for persons in the motor incomplete SCI group was 1.17 (supported standing) to 6.22 (wheeling on grass), and 2.26 (billiards) to 16.25 (hand cycling) for activities of daily living and fitness/recreation, respectively. The MET range for activities of daily living for persons in the group with motor complete SCI was 1.27 (dusting) to 4.96 (wheeling on grass) and 1.47 (bait casting) to 7.74 (basketball game) for fitness/recreation.

CONCLUSIONS

The foundation for a compendium of energy expenditure for physical activities for persons with SCI has been created with the completion of this study. In the future, others will update and expand the content of this compendium as has been the case with the original compendium for the able-bodied.

Serum leptin levels following acute experimental spinal cord injury

BACKGROUND/OBJECTIVE

Spinal cord injury influences many hormones that are known to be involved in the modulation of neurotrophic, neurogenic, and neuroprotective events. Recent studies showed that leptin could be neuroprotective, enhancing neuronal survival in vitro and in vivo. The objective of this study was to evaluate the pattern of the serum leptin levels in rats during acute traumatic SCI.

METHODS

Forty male Sprague-Dawley rats were divided randomly into 4 groups. In the control group, neither laminectomy nor SCI was performed; only laminectomy was performed without SCI in the sham group. In the cervical and thoracic spinal trauma groups, laminectomies were performed following the same trauma procedure. Blood samples were drawn 2, 6, 12, and 24 hours after the procedures and assayed immediately.

RESULTS

In the first 2 hours, levels of leptin were similar in control and sham-operated groups and higher in neurotrauma groups (P < 0.05). At the sixth hour, leptin levels increased in the sham-operated group, decreased in the neurotrauma groups (P < 0.05), and did not change in the control group (P > 0.05). At the 12th hour, the levels of leptin increased in all groups (P > 0.05). At the 24th hour, they decreased in the control, sham-operated, and cervical groups (P < 0.05); levels did not change in the thoracic group (P > 0.05). The decrease was higher in the control group than in the other groups (P < 0.05).

CONCLUSIONS

Activation of endogenous leptin secretion started immediately after the SCI. The level of neurologic lesion (either cervical or thoracic regions) affected the levels of serum leptin differently, but with the exception of the first 12-hour period, this difference did not reach a statistically significant level.

Stress Analyses Coupled With Damage Laws to Determine Biomechanical Risk Factors for Deep Tissue Injury During Sitting

Deep tissue injury (DTI) is a potentially life-threatening form of pressure ulcer that onsets in muscle tissue overlying bony prominences and progresses unnoticeably to more superficial tissues. To minimize DTI, the efficacy of wheelchair cushions should be evaluated not only based on their performance in redistributing interface pressures but also according to their effects on stress concentrations in deep tissues, particularly muscles. However, a standard bioengineering approach for such analyses is missing in literature. The goals of this study were to develop an algorithm to couple finite element (FE) modeling of the buttocks with an injury threshold for skeletal muscle and with a damage-stiffening law for injured muscle tissue, from previous animal experiments, to predict DTI onset and progression for different patient anatomies and wheelchair cushions. The algorithm was also employed for identifying intrinsic (anatomical) biomechanical risk factors for DTI onset. A set of three-dimensional FE models of seated human buttocks was developed, representing different severities of pathoanatomical changes observed in chronically sitting patients: muscle atrophy and “flattening” of the ischial tuberosity (IT). These models were then tested with cushions of different stiffnesses representing products available on the market and semirigid supports. Outcome measures were the percentage of damaged muscle tissue volumes after 90min and 110min of simulated continuous immobilized sitting as well as muscle injury rates post-60min, -90min, and -110min of continuous sitting. Damaged muscle volumes grew exponentially with the level of muscle atrophy. For example, simulation of a subject with 70% muscle atrophy sitting on a soft cushion showed damage to 33% of the muscle volume after 90min of immobilized sitting, whereas a comparable simulation with a nonatrophied muscle yielded only 0.4% damaged tissue volume. The rates of DTI progression also increased substantially with increasing severities of muscle atrophy, e.g., 70% atrophy resulted in 8.9, 2.7, and 1.6 times greater injury rates compared with the “reference” muscle thickness cases, after 60min, 90min, and 110min of sitting, respectively. Across all simulation cases, muscle injury rate was higher when a “flatter” IT was simulated. Stiffer cushions increased both the extent and rate of DTI at times shorter than 90min of continuous sitting, but after 110min, volumes and rates of tissue damage converged to approximately similar values across the different cushion materials. The present methodology is a practical tool for evaluating the performances of cushions in reducing the risk for DTI in a manner that goes far beyond the commonly accepted measurements of sitting pressures.

The discovery of drugs for obesity, the metabolic effects of leptin and variable receptor pharmacology: perspectives from beta3-adrenoceptor agonists

Although beta3-adrenoceptor (beta3AR) agonists have not become drugs for the treatment of obesity or diabetes, they offer perspectives on obesity drug discovery, the physiology of energy expenditure and receptor pharmacology. beta3AR agonists, some of which also stimulate other betaARs in humans, selectively stimulate fat oxidation in rodents and humans. This appears to be why they improve insulin sensitivity and reduce body fat whilst preserving lean body mass. Regulatory authorities ask that novel anti-obesity drugs improve insulin sensitivity and reduce mainly body fat. Drugs that act on different targets to stimulate fat oxidation may also offer these benefits. Stimulation of energy expenditure may be easy to detect only when the sympathetic nervous system is activated. Leptin resembles beta3AR agonists in that it increases fat oxidation, energy expenditure and insulin sensitivity. This is partly because it raises sympathetic activity, but it may also promote fat oxidation by directly stimulating muscle leptin receptors. The beta1AR and beta2AR can, like the beta3AR, display atypical pharmacologies. Moreover, the beta3AR can display variable pharmacologies of its own, depending on the radioligand used in binding studies or the functional response measured. Studies on the beta3AR demonstrate both the difficulties of predicting the in vivo effects of agonist drugs from in vitro data and that there may be opportunities for identifying drugs that act at a single receptor but have different profiles in vivo.

Body composition in paraplegic men

To investigate alterations in the body composition of paraplegic men, 31 complete paraplegic men thoracic (T)4-T 12 neurological level of injury, 16 with paraplegia above (high), and 15 below (low) thoracic 7, were compared with 33 able-bodied men. Whole body dual X-ray absorptiometry was used to estimate regional (arms, legs) and total body bone mineral density (g/cm(2)), lean, and fat mass (g).The influence of the neurological level of injury and the duration of paralysis in relation with the above parameters were also investigated. Body mass index, bone mineral density, and lean mass were significantly decreased (p < 0.0005) and fat mass was increased (p < 0.05) in the legs and total body composition in paraplegics. Bone mineral density was significantly lower in high paraplegics' arms compared with low paraplegics (p = 0.028). The correlation of body mass index with fat mass was statistically significant in all paraplegics and controls (r = 0.57, p = 0.001 and r = 0.73, p = 0.0001, respectively) and in low paraplegics (r = 0.72, p = 0.004). Legs' bone mineral density and arms' fat mass were correlated with the duration of paralysis in all paraplegics (r = -0.46, p = 0.009 and r = 0.43, p = 0.020, respectively) and in high paraplegics (r = 0.73, p = 0.001 and r = 0.55, p = 0.042, respectively). Total fat mass was correlated with the duration of paralysis in high paraplegics (r = 0.5, p = 0.05). These results suggest body composition changes in paraplegics.

Clinical assessment and management of obesity in individuals with spinal cord injury: a review

BACKGROUND

Diagnosing and managing obesity in individuals with spinal cord injury (SCI) remain challenging.

METHODS

Literature on the epidemiology, impact, and management of obesity in individuals with SCI was reviewed.

FINDINGS

Although nearly 66% of individuals with SCI are either overweight or obese, little guidance is available to measure and monitor obesity in the clinical setting. The use of anthropometric indices and specific cut points available for able-bodied persons is limited by the body composition changes that follow SCI. Indices of upper body obesity warrant examination in SCI because they provide an index of central obesity, which is more closely linked to some obesity-related conditions than is overall obesity. Investigations into the sequelae of excess body fat and its distribution are also needed in SCI because past research in this area has been inconclusive. Although limited, evidence regarding obesity interventions in SCI may be promising.

CONCLUSIONS

The best anthropometric tool to define obesity in the clinical setting remains unknown. SCI-specific assessment tools and a better understanding of the sequelae of excess body weight will lead to better targeting of prevention and treatment efforts. More research is needed on the individual components of a weight management program unique to SCI. Until then, providers are urged to use a team approach and draw on existing resources and applicable research in able-bodied individuals to facilitate weight management in individuals with SCI.

Basal metabolic rate and autonomic nervous system dysfunction in men with spinal cord injury

OBJECTIVES

The purpose of this study was to determine the relationship between autonomic nervous system dysfunction and basal metabolic rate (BMR), and the effect of spasticity on basal metabolic rate.

RESEARCH METHOD AND PROCEDURES

Twenty men (11 paraplegic and 9 tetraplegic) with American Spinal Injury Association (ASIA)-A and -B grade chronic spinal cord injury (SCI) participated in this study. Total body fat mass and lean tissue mass were measured in all participants using DXA by standard methods. Patients were allocated into 2 groups to determine the effect of autonomic nervous system dysfunction on BMR: Group I (T6 and upper-level injuries with history of autonomic dysreflexia) and Group II (T7 and lower-level injuries without history of autonomic dysreflexia). Measurements of BMR were determined by indirect calorimetry under standardized conditions.

RESULTS

There were 13 patients in Group I and 7 patients in Group II and the difference between these two in terms of time since injury, BMI, age, weight, lean tissue mass, BMR, and BMR/kg were not significant.

CONCLUSION

We concluded that autonomic nervous system dysfunction does not affect BMR, and it might be ignored in considering energy needs in spinal cord injury.

Cardiovascular Health and Fitness in Persons with Spinal Cord Injury

There are many issues after spinal cord injury that have an impact on cardiovascular health and fitness. This article discusses many of the secondary conditions and changes that occur and how they are affected by maintenance of an active lifestyle. It also discusses many of the benefits and difficulties individuals face in maintaining a regular exercise program after spinal cord injury.

Prevalence of Obesity After Spinal Cord Injury

The prevalence of obesity has been continuously increasing in the United States. Obesity has crossed the borders of the able-bodied populations and extended to populations with disabilities, including spinal cord injury (SCI). The magnitude and the prevalence of obesity after SCI are not clearly defined. The purpose of the current review is to discuss the body of literature on the prevalence of obesity among individuals with SCI. The review will show that the prevalence of obesity after SCI is an issue that needs to be further addressed and specifically correlated to mortality rates in SCI. Body mass index (BMI) criteria need to be adjusted to meet the changes in body composition after SCI, specifically increasing fat mass and percent body fat. Prevalence of overweight and obesity in SCI by sex, age, and ethnic group needs further investigation to determine the actual magnitude of the problem, which appears to exceed epidemic proportions. Moreover, SCI-specific factors such as level of injury, American Spinal Injury Association (ASIA) impairment classification, and time since injury need to be further correlated to the prevalence of obesity after SCI.

Assessment of mechanical conditions in sub-dermal tissues during sitting: A combined experimental-MRI and finite element approach

A common but potentially severe malady afflicting permanent wheelchair users is pressure sores caused by elevated soft tissue strains and stresses over a critical prolonged period of time. Presently, there is paucity of information regarding deep soft tissue strains and stresses in the buttocks of humans during sitting. Strain and stress distributions in deep muscle and fat tissues were therefore calculated in six healthy subjects during sitting, in a double-donut Open-MR system, using a "reverse engineering" approach. Specifically, finite element (FE) models of the undeformed buttock were built for each subject using MR images taken at the coronal plane in a non-weight-bearing sitting posture. Using a second MR image taken from each subject during weight-bearing sitting we characterized the ischial tuberosity sagging toward the sitting surface in weight-bearing, and used these data as displacement boundary conditions for the FE models. These subject-specific FE analyses showed that maximal tissue strains and stresses occur in the gluteal muscles, not in fat or at the skin near the body-seat interface. Peak principal compressive strain and stress in the gluteus muscle were 74+/-7% and 32+/-9 kPa (mean+/-standard deviation), respectively. Peak principal compressive strain and stress in enveloping fat tissue were 46+/-7% and 18+/-4 kPa, respectively. Models were validated by comparing measured peak interface pressures under the ischial tuberosities (17+/-4 kPa) with those calculated by means of FE (18+/-3 kPa), for each subject. This is the first study to quantify sub-dermal tissue strain and stress distributions in sitting humans, in vivo. These data are essential for understanding the aetiology of pressure sores, particularly those that were recently termed "deep tissue injury" at the US National Pressure Ulcer Advisory Panel (NPUAP) 2005 Consensus Conference.

The role of leptin and ghrelin in the regulation of food intake and body weight in humans: a review

Leptin and ghrelin are two hormones that have been recognized to have a major influence on energy balance. Leptin is a mediator of long-term regulation of energy balance, suppressing food intake and thereby inducing weight loss. Ghrelin on the other hand is a fast-acting hormone, seemingly playing a role in meal initiation. As a growing number of people suffer from obesity, understanding the mechanisms by which various hormones and neurotransmitters have influence on energy balance has been a subject of intensive research. In obese subjects the circulating level of the anorexigenic hormone leptin is increased, whereas surprisingly, the level of the orexigenic hormone ghrelin is decreased. It is now established that obese patients are leptin-resistant. However, the manner in which both the leptin and ghrelin systems contribute to the development or maintenance of obesity is as yet not clear. The purpose of this review is to provide background information on the leptin and ghrelin hormones, their role in food intake and body weight in humans, and their mechanism of action. Possible abnormalities in the leptin and ghrelin systems that may contribute to the development of obesity will be mentioned. In addition, the potentials of leptin and ghrelin as drug targets will be discussed. Finally, the influence of the diet on leptin and ghrelin secretion and functioning will be described.

A review of body mass index and waist circumference as markers of obesity and coronary heart disease risk in persons with chronic spinal cord injury

STUDY DESIGN

Literature review.

BACKGROUND

Increased fat mass and coronary heart disease (CHD) are secondary complications of chronic spinal cord injury (SCI). In able-bodied populations, body mass index (BMI, body weight (kg)/height (m(2))) is a widely used surrogate marker of obesity and predictor of CHD risk. Waist circumference, an accurate and reproducible surrogate measure of abdominal visceral adipose tissue, is also associated with CHD risk (more so than BMI) in able-bodied populations.

OBJECTIVE

To review the literature on the accuracy of BMI and waist circumference as surrogate measures of obesity and CHD risk in persons with chronic SCI.

SETTING

Ontario, Canada.

METHODS

Literature review.

RESULTS

In the SCI population, BMI is an insensitive marker of obesity, explains less of the variance in measured percent fat mass than in the able-bodied, and is inconsistently related to CHD risk factors. This may be due to potential measurement error, and to the inability of BMI to distinguish between fat and fat-free mass and to measure body fat distribution. Waist circumference has not been validated as a surrogate measure of visceral adipose tissue, however preliminary evidence supports a relationship between waist circumference and CHD risk in the SCI population.

CONCLUSIONS

We recommend that SCI-specific BMI classifications be determined. We also recommend that accuracy and reliability of waist circumference as a surrogate measure of visceral adipose tissue and CHD risk be determined in men and women with long-standing paraplegia and tetraplegia.

Tetraplegic subjects have hyperleptinaemia with marked circadian variation

OBJECTIVE

The disruption between the brain and the spinal cord leads to a decentralized sympathetic nervous system in people with chronic, cervical spinal cord lesions. These tetraplegic subjects are prone to disorders of energy metabolism and osteoporosis, and they experience alterations in their body composition with a relative accumulation of fat. The adipocyte-derived cytokine leptin is a key signal in caloric intake and energy expenditure, and it might modify bone remodelling, possibly regulated by sympathetic neuronal signalling. In able-bodied subjects leptin exhibits circadian variations, possibly mediated via sympathetic neurones. We have examined the plasma concentration of leptin among tetraplegics, to determine whether plasma leptin in these subjects exhibits circadian variations.

MEASUREMENTS AND RESULTS

Blood samples were collected during a 24-h study period from tetraplegic subjects (n = 6) and from able-bodied controls (n = 8). Fasting, tetraplegic subjects had mean plasma concentrations of leptin about four times those of able-bodied controls (P < 0.05). In tetraplegia, plasma leptin was negatively correlated with total lean mass (r =-0.88, P < 0.05) but correlated positively with total fat mass (r = 0.89, P < 0.05). A marked circadian variation in plasma leptin concentrations was more evident in tetraplegia than in able-bodied controls.

CONCLUSION

Plasma leptin is markedly elevated and it shows more prominent circadian variations in tetraplegia compared with able-bodied subjects. Possibly the regulation of leptin metabolism is impaired among these patients. This might distort thermogenesis and energy expenditure, thus explaining the enhanced risk of the metabolic syndrome and of osteoporosis among tetraplegic subjects.

Energy expenditure in chronic spinal cord injury

PURPOSE OF REVIEW

Obesity is a common secondary complication of chronic spinal cord injury and is associated with adverse metabolic sequelae. Because positive energy balance is the fundamental cause of obesity, we herein review the current knowledge pertaining to total daily energy expenditure, including resting metabolic rate, the thermic effect of food, and physical activity, in the spinal cord injury population.

RECENT FINDINGS

Commonly used equations to predict resting metabolic rate overestimate measured requirements in chronic spinal cord injury by 5-32%. Measured resting metabolic rate is 14-27% lower in persons with spinal cord injury versus those without, due to decreased fat-free mass and sympathetic nervous system activity in this population. However, preliminary evidence suggests that neither the metabolic activity of the fat-free body, nor the obligatory phase of the thermic effect of food is different between those with and without injury. Physical activity levels, especially in those with tetraplegia and complete lesions, are lower than recommended or lower than those of able-bodied persons.

SUMMARY

New equations to predict resting metabolic rate should be validated and prospectively tested in a large sample of men and women with complete and incomplete paraplegia and tetraplegia. Whether the facultative phase of the thermic effect of food is different between those with and without SCI remains to be elucidated. Persons with chronic spinal cord injury, and perhaps those with tetraplegia and complete lesions especially, should be encouraged to engage in increased frequency, intensity and/or duration of physical activity. Future research efforts should explore the effects of level and completeness of neurological lesion on resting metabolic rate, thermic effect of food, and physical activity.

Circulating leptin concentrations can be used as a surrogate marker of fat mass in acute spinal cord injury patients

To determine the acute effect of neurological lesion on body composition, plasma leptin level, and the lipid profile, 7 male patients with acute and complete spinal cord injury (SCI) and 9 able-bodied (AB) males were investigated. At 16, 24, 36, and 48 weeks after injury, plasma leptin level and the lipid profile were analyzed, while whole body (WB) and regional fat mass (FM) and fat-free soft tissue (FFST) were measured by dual-energy x-ray absorptiometry (DXA). At all stages, despite no difference being found between both groups for body mass index (BMI), SCI patients had higher FM at WB (P < .01), lower (P < .01), and upper limbs (P < .05), while FFST was lower at WB (P < .05) and lower limbs (P < .01). The leptin level increased gradually from week 24 and was higher at weeks 16, 36, and 48 in SCI patients than in AB patients (7.0 +/- 3.9; 9.7 +/- 5.1; 10.6 +/- 5.3, respectively, v 3.5 +/- 2.5 ng. mL(-1)). SCI patients had lower high-density lipoprotein-cholesterol (HDL-C) (P < .05) and apolipoprotein (apo) A1 (P < .01), while no difference was found for total cholesterol (TC), low-density lipoprotein-cholesterol (LDL-C), or ApoB levels. At all stages, leptin was strongly and positively correlated with WB and regional FM % (r > 0.75; P < .05) and with TC, LDL-C, and ApoB levels (r > 0.65; P < .05). Leptin was negatively correlated with FFST and the ApoA1/ApoB ratio (r > -0.75; P < .05). In conclusion, neurological lesion induced an early and acute alteration in body composition and lipid profile. The strong relationship between serum leptin and FM suggests that this hormone can be used as a surrogate marker of FM in acute SCI patients and thus would serve as a good indicator for cardiovascular disease risk.