Ultrasonographic assessment of lipodystrophy in HIV-1-infected patients

Purpose

We performed a cross-sectional study of physical changes in HIV-infected adults to evaluate the role of ultrasonography for the diagnosis of lipodystrophy.

Materials and methods

Sixty HIV-infected patients were recruited from 1 June to 31 December 2006. A total of 34 patients were included in the lipodystrophy group and 26 in no lipodystrophy group. Thickness of subcutaneous fat was measured twice with a high-frequency (15 MHz) transducer by transverse scans at four skin-based reference points: the periumbilical region, the brachial region, the crural region and the malar region. Visceral fat thickness was determined with a low-frequency (3.75 MHz) transducer at two skin reference points: perirenal fat diameter and visceral abdominal fat.

Results

Compared with HIV-infected patients without lipodystrophy, those with lipoatrophy or mixed lipodystrophy had thinner facial, arm and leg fat, whereas patients with lipodystrophy showed thicker intra-abdominal fat. The median of the ratio between intra-abdominal fat and subcutaneous fat and between perirenal fat diameter and body mass index in the lipodystrophy group was higher than in the no lipodystrophy group. The measurements of brachial, malar and crural fat were significantly lower in patients with lipodystrophy.

Conclusions

We consider the ratio between visceral adipose tissue and subcutaneous adipose tissue and the thickness of malar fat to be the most useful ultrasonographic parameters for the early diagnosis of lipodystrophy in HIV-infected patients on highly active antiretroviral therapy.     

Effects of endurance exercise training on metabolic and inflammatory parameters in HIV-1-infected patients with secondary lipodystrophy and diabetes

Regular physical exercise exerts positive effects, prolonging survival and improving quality of life of HIV-1-infected patients. A 3-month supervised endurance training program in subjects with AIDS-related lipodystrophy and type 2 diabetes mellitus improved aerobic capacity, pancreatic beta-cell function and immune profile, with a reduction in the proinflammatory cytokines monocyte chemotactic protein-1 and tumor necrosis factor-alpha. Appropriate physical exercise combined with specific pharmacological and dietetic therapies could prevent the development of secondary metabolic and cardiovascular disorders.     

Exercise training and autonomic nervous system activity in obese individuals

PURPOSE: This study was designed to investigate the effects of 12 wk of exercise training on autonomic nervous system (ANS) in 18 obese middle-aged men (N = 9) and women (N = 9) (age: 41.6 +/- 1.2 yr; BMI: 27.3 +/- 0.4 kg x m(-2); %fat: 29.6 +/- 1.3%, mean +/- SE). METHODS: Each subject participated in an aerobic exercise training at anaerobic threshold (AT), consisting of 30 min/session, 3 times/wk, for 12 consecutive weeks. The ANS activities were assessed by means of power spectral analysis of heart rate variability (HRV) at resting condition before, at 5 wk, and after the exercise program. RESULTS: The exercise training resulted in a significant decrease in body mass, BMI, and % fat (P < 0.01) but not in lean body mass (P > 0.05) together with a significant increase in the AT VO2 (P < 0.01). Our power spectral data indicated that there were significant increases in the low-frequency component associated with the sympathovagal activity (0.03--0.15 Hz, 348.5 +/- 66.8 vs 694.7 +/- 91.5 ms(2), P < 0.01), the high-frequency vagal component (0.15--0.4 Hz, 146.3 +/- 30.4 vs 347.7 +/- 96.5 ms(2), P < 0.05), and the overall autonomic activity as evaluated by total power (0.03--0.4 Hz, 494.8 +/- 88.5 vs 1042.4 +/- 180.9 ms(2), P < 0.01) of HRV after the training. CONCLUSIONS: Twelve weeks of exercise training has significantly improved both the sympathetic and parasympathetic nervous activities of the obese individuals with markedly reduced ANS activity, suggesting a possible reversal effect of human ANS functions. These favorable changes may also have an influence on the thermoregulatory control over the obesity.     

Moderate and high intensity exercise training in HIV-1 seropositive individuals: a randomized trial

HIV-infected individuals are frequently active, but guidelines for exercise in this population lack scientific support, since studies on the effects of exercise training on immunologic variables of HIV-1 positive individuals have shown conflicting results. Exercise capacity, immunologic markers (CD4, CD8 and CD4:CD8 ratio), anthropometric measurements, and depression scores were evaluated to compare the effects of two intensities of aerobic exercise on HIV-1 seropositive individuals. Twenty-one healthy subjects (14 men, 7 women), carriers of the HIV-1 virus (CD4>200 cells x mm(-3)), and inactive for at least 6 months, completed a 12 week exercise training program (36 sessions of 1 h, 3 times per week), in a moderate intensity group (60+/-4% of maximal heart rate) or a high intensity group (84+/-4% of maximal heart rate). Exercise capacity estimated by treadmill time was increased significantly in both moderate intensity (680+/-81 s before; 750+/-151 s after) and high intensity (651+/-122 s before; 841+/-158 s after) groups, but the high intensity group presented a significantly larger increment (p<0.01). There were no significant changes in the immunologic variables, anthropometric measurements or depression scores. Thus, HIV-seropositive individuals that participate in moderate and high intensity exercise programs are able to increase their functional capacity without any detectable changes in immunologic variables, anthropometric measurements or depression scores.     

Exercise considerations in hypertension,obesity, and dyslipidemia

Sports medicine practitioners who care for a wide array of athletes and active individuals will consistently face issues regarding chronic cardiovascular diseases and their associated risk factors. Among these, hypertension, obesity, and dyslipidemia are common clinical conditions that may be encountered even amongst elite caliber athletes. Consequently, those entrusted with the care of this active population must recognize the presence of these disorders and feel comfortable with their management in the face of continued sports or exercise participation. This article reviews the pathophysiology of these conditions as they relate to athletes and outlines the value of continued exercise in the management of each of these entities while addressing the specific and unique treatment needs of active individuals.     

Exercise recommendations for individuals with spinal cord injury

Persons with spinal cord injury (SCI) exhibit deficits in volitional motor control and sensation that limit not only the performance of daily tasks but also the overall activity level of these persons. This population has been characterised as extremely sedentary with an increased incidence of secondary complications including diabetes mellitus, hypertension and atherogenic lipid profiles. As the daily lifestyle of the average person with SCI is without adequate stress for conditioning purposes, structured exercise activities must be added to the regular schedule if the individual is to reduce the likelihood of secondary complications and/or to enhance their physical capacity. The acute exercise responses and the capacity for exercise conditioning are directly related to the level and completeness of the spinal lesion. Appropriate exercise testing and training of persons with SCI should be based on the individual's exercise capacity as determined by accurate assessment of the spinal lesion. The standard means of classification of SCI is by application of the International Standards for Classification of Spinal Cord Injury, written by the Neurological Standards Committee of the American Spinal Injury Association. Individuals with complete spinal injuries at or above the fourth thoracic level generally exhibit dramatically diminished cardiac acceleration with maximal heart rates less than 130 beats/min. The work capacity of these persons will be limited by reductions in cardiac output and circulation to the exercising musculature. Persons with complete spinal lesions below the T(10) level will generally display injuries to the lower motor neurons within the lower extremities and, therefore, will not retain the capacity for neuromuscular activation by means of electrical stimulation. Persons with paraplegia also exhibit reduced exercise capacity and increased heart rate responses (compared with the non-disabled), which have been associated with circulatory limitations within the paralysed tissues. The recommendations for endurance and strength training in persons with SCI do not vary dramatically from the advice offered to the general population. Systems of functional electrical stimulation activate muscular contractions within the paralysed muscles of some persons with SCI. Coordinated patterns of stimulation allows purposeful exercise movements including recumbent cycling, rowing and upright ambulation. Exercise activity in persons with SCI is not without risks, with increased risks related to systemic dysfunction following the spinal injury. These individuals may exhibit an autonomic dysreflexia, significantly reduced bone density below the spinal lesion, joint contractures and/or thermal dysregulation. Persons with SCI can benefit greatly by participation in exercise activities, but those benefits can be enhanced and the relative risks may be reduced with accurate classification of the spinal injury.     

HAART治疗HIV-1慢性感染儿童外周血特异性CTL的反应特点

目的 观察高效抗逆转录病毒治疗(HAART)前后人类免疫缺陷病毒Ⅰ型(HIV-1)慢性感染儿童外周血HIV-1特异性CTL的反应特点,并分析其影响因素.方法 采集24例HIV-1 慢性感染儿童外周血并分离PBMCs,常规进行CD4 T细胞绝对数和血浆病毒载量测定.应用tetramer染色技术和ELISPOT技术分别测定HIV-1表位特异性CTL频率和IFN-γ产生细胞的数量.结果 在80%的HIV-1慢性感染儿童外周血可检测到HIV-1特异性的tetramer CTL细胞和HIV-1表位肽刺激的IFN-γ产生细胞.未经HAART治疗和HAART治疗失败的儿童,其体内CTL反应明显强于HAART治疗成功的儿童,并且这种CTL反应与HAART治疗时间呈明显的负相关.结论 HAART治疗后外围血HIV-1特异性CTL反应明显降低,持续的HIV-1抗原刺激是维持外周血HIV-1特异性CTL反应的主要因素.     

Exercise and training in mitochondrial myopathies

The intriguing concept of exercise training as therapy for mitochondrial disease is currently unsettled: in the unique setting of mitochondrial heteroplasmy, what are the effects of chronic exercise on skeletal muscle containing a mixture of mutated and wild-type mitochondrial DNA (mtDNA)? Furthermore, what are the consequences of habitual physical inactivity on mitochondrial heteroplasmy? In patients with mtDNA defects, deleterious effects of limited physical activity likely magnify the mitochondrial oxidative impairment contributing to varying degrees of exercise intolerance. Normal adaptive responses to endurance training offer the potential to increase levels of functional mitochondria, improving exercise tolerance. The few clinical studies assessing such training effects in patients with mtDNA defects have unequivocally demonstrated physiologic and biochemical adaptations that improve exercise tolerance and quality of life. Uncertain, however, is the training effect on mitochondrial heteroplasmy. To determine therapeutic advisability of endurance training, it remains imperative to establish whether: reported increases in mutant mtDNA levels can be offset by increases in absolute wild-type mtDNA levels; and chronic physical inactivity leads to a selective down-regulation of wild-type mtDNA. Resistance exercise training offers an alternate, innovative therapeutic approach in patients with sporadic mtDNA mutations; exercise-induced transfer of normal mtDNA templates from muscle satellite cells to mature myofibers, thereby lowering mutation load (increasing functional mitochondrial load). Efficacy and safety of this approach needs to be replicated in a larger group of patients. Currently, appropriate recommendation (either in support or against) exercise training in mitochondrial disease is lacking, which is frustrating for physicians and disheartening for patients. Although considerable progress has been made, an immediate urgency exists to resolve the effects of chronic exercise on skeletal muscle in patients with heteroplasmic mtDNA mutations.     

Exercise and training in patients with chronic obstructive lung disease

Exercise protocols and training are used more and more in diagnostic procedures and as a tool in improving physical, social and psychological functioning in chronic obstructive lung disease patients. Before starting a training programme in chronic obstructive lung disease patients, one should exclude ventilatory-limited patients from the group. A maximal ergometer test with arterial blood samples or pulse oximetry must be performed. In mild forms of chronic obstructive lung disease with no ventilatory insufficiency demonstrable with exercise testing, the patient can be trained with no restrictions. Endurance training is permitted. It should be noted that it is possible to train the muscular and cardiovascular system up to a new, possible ventilatory maximum. In severe chronic obstructive lung disease endurance training is accompanied by hypoxia, with an associated risk of rhythm disturbances and right heart failure. Training with supplemental oxygen can reduce this risk, but should be done only under close medical supervision. In very severe chronic obstructive lung disease, when endurance training is only marginally possible even with supplemental oxygen, suppleness, coordination and relaxation exercises should be emphasised in rehabilitation programmes. Postural exercises and breathing control exercises can also give great subjective improvements in this often very disabled group of patients. Furthermore they can reduce fear and panic when dyspnoea occurs. Training of the respiratory muscles in patients with chronic obstructive lung disease must be regarded as an experimental therapy. The clinical importance remains uncertain. Exercise-induced bronchoconstriction should not limit exercises or training, provided it is treated correctly.     

Exercise training in patients with impaired left ventricular function

Advances in the understanding of the pathophysiology of congestive heart failure have guided efforts in formulating effective treatment strategies. The epidemiology, etiology, and medical management of congestive failure are reviewed. The changing approaches to exercise and exercise training in patients with heart failure are discussed. Recent studies of the impact of exercise training in this important patient group are presented.     

Exercise training and coronary collateral circulation

This review examines the potential for an exercise-induced increase in coronary collateral circulation, with specific reference to the role and functional significance of collateral vessels, highlighting animal and human studies in particular, and their inherent methodological limitations. Exercise training may enhance myocardial oxygen supply by promoting transient periods of myocardial ischemia, a potent trigger of collateral growth. Some human studies have shown that moderate-to-high intensity training can result in a higher double product at the onset of angina and/or ischemic ST-segment depression, suggesting that myocardial oxygen supply has increased. Attempts to use thallium-201 exercise scintigraphy to assess myocardial perfusion before and after a physical training program have produced conflicting data, whereas angiographic studies in group trials have, without exception, yielded disappointing results. Thus, direct evidence that exercise stimulates collateralization in humans is lacking.     

Exercise training in patients with chronic obstructive pulmonary disease.

Most patients with chronic obstructive pulmonary disease (COPD) demonstrate positive responses to exercise conditioning. Dyspnea is reduced and work tolerance is extended with little or no change in pulmonary function noted. Possible explanations for the increased ability to better tolerate exercise and activities of daily living (ADL) after training include: 1) psychological encouragement, 2) improvements in mechanical efficiency, 3) improved cardiovascular conditioning, 4) improved muscle function, 5) biochemical adaptations responsible for reducing glucose utilization, 6) desensitization to dyspnea, and 7) contributions from better self-care. However, not all patients respond positively to exercise conditioning. This may represent differences in patient selection, training approaches, and/or comorbidity issues commonly seen in patients with COPD. Alternatively, the answer may reside in devising an optimal training intensity, duration, and frequency combination for patients with COPD. This is not an easy matter because of the diversity of patients categorized as COPD. We have reviewed these issues from the available data and presented areas where additional research is warranted. What is needed at present is a series of well-controlled studies that focus on identifying and improving training responses in patients with COPD. Secondary to this issue is the long term epidemiologic surveillance of trained patients to document sustained effects.     

Exercise training and cytokines in breast cancer survivors

The purpose of this randomized controlled trial was to determine the effects of an 8-week (aerobic+strength) exercise training program (3 sessions/week) on the circulating cytokine levels of breast cancer survivors. We randomly allocated 16 female survivors of breast cancer (mean±SD age: 50±5 years) to an intervention or usual care (control) group (N=8 in each group). The intervention group followed an 8-week exercise program consisting of 3 sessions/week (session duration: 90?min). We measured the levels of the following cytokines before and after the intervention: beta-NGF, CTACK, eotaxin, FGF basic, G-CSF, gmCSFα, HGF, ICAM1, IFNα2, IFNγ, IL1α, IL1?, IL1ra, IL2, IL2ra, IL3, IL4, IL6, IL7, IL8, IL9, IL10, IL12, IL13, IL15, IL16, IL17, IL18, IP10, LIF, MCS-F, MIP1α, MIP1β, MIF, MCP1, MCP3, MIG, PDGF bb, SCF, SCGFβ, SDF1α, TRAIL, TNFα, TNFβ, VCAM1, and VEGF. We only observed a significant interaction (group*time) effect for CTACK ( P=0.016), with mean values remaining stable in the intervention group but increasing over time in controls. The intervention program did not induce a significant decrease in the main breast cancer-related cytokines such as IL6 and IL8. A combined (aerobic+strength) 8-week exercise training intervention did not induce major changes in the basal cytokine levels of breast cancer survivors.     

Exercise responses and adaptations in rowers and spinal cord injury individuals

Elite rowers (ROWERS) and those who have had a spinal cord injury (SCI) are different physically in many realms. Both have physical activity histories that affect their lower-extremity extensor muscles in a dramatically different fashion. ROWERS can sustain a 500-W power output during their 5- to 6-min race. After a complete SCI, a 75-W power output might be achieved during a VO(2peak) test. Elite SCI wheelchair racers can achieve a higher value that is similar to that of a sedentary able-bodied person. ROWERS can attain a VO(2 max) of more than 7.5 L.min(-1) and can tolerate a blood lactate of 30 mmol.L(-1). After a complete SCI in which muscles become markedly atrophied, a peak VO(2) of 2 L.min(-1) and a blood lactate of 10 mmol.L(-1) might be achieved. ROWERS rely on the 75% slow-twitch fiber composition of their trained thigh muscles to train and race. Such activity modestly increases fiber size and markedly increases mitochondrial content. After a complete SCI, affected muscle fibers markedly atrophy, maintain most of their mitochondrial content, and become fast-twitch. These data suggest remarkable plasticity of physical function to the extreme that a marked increase in energy demanding, rather continuous physical activity can make a muscle more "slow-twitch"; so it will demand less energy when contracted. In contrast, SCI eventually causes muscle to be composed of more fast-twitch fibers. Molecular biologists may explain why fast-twitch fibers, which appear ideal for some athletes because of their high power output, are abundant in muscles that are seldom recruited. Until then, our results indicate that the fiber type composition of muscle in humans is stable unless extreme alterations in physical activity are endured.     

Exercise training in chronic kidney disease patients

Chronic kidney disease (CKD) is a major public health problem that affects an estimated 1.7 million Australians. Patients with CKD commonly progress to end-stage kidney disease (ESKD) requiring dialysis and/or kidney transplantation. They are at high risk of cardiovascular disease and many die from this prior to reaching ESKD. Few therapies are available to slow CKD progression and reduce cardiovascular morbidity and mortality. The benefit of exercise training has been well demonstrated in a range of disease conditions including ESKD and was recently highlighted by a systematic review in haemodialysis patients and a recent Cochrane review of all stages of CKD. However, the effects of exercise training in patients with CKD have not been extensively investigated. Our systematic search of the literature found only ten clinical trials in this area. The aim of this review is to review these studies, and to discuss the findings, safety considerations and suggest future areas of research. Overall, the majority of the studies are small, non-randomized, non-controlled trials. They have found that exercise training can increase exercise capacity, improve muscle strength and function, decrease blood pressure, and improve inflammation and oxidative stress biomarkers. The effects of exercise training on kidney function, cardiovascular disease and quality of life are unknown. Studies are needed to answer these questions and develop evidence-based exercise training guidelines for individuals with CKD.