Comparative effects of various running exercise modalities on femoral bone quality in rats

BACKGROUND

It is now well established that physical exercise is an effective preventive method to reduce and treat certain chronic diseases, particularly musculoskeletal disorders. At the bone level, running exercise is well known for its positive effects on various parameters of bone quality. There is, however, no consensus regarding the effects of different running exercise modalities on bone quality.

AIM

The objective of this study was to compare the effects of three treadmill running modalities: intermittent, moderate continuous, and a combination of both-on bone quality parameters in rats.

METHODS

Thirty-nine, 5-week-old, male Wistar rats were randomly divided in 4 groups: sedentary control (SED; n = 10), intermittent running exercise (IE; n = 10), continuous running exercise (CE; n = 10) and combined running exercise (COME; n = 9). Rats in running groups were exercised 45 min/day, 5 days/week, for 8 consecutive weeks. Femoral micro-architectural parameters were assessed by micro-CT; femoral osteocyte apoptosis, osteoclast resorption and bone histomorphometry were assessed by histology.

RESULTS

Femoral trabecular thickness in the combined running group was increased (p < 0.0001) compared to respective results in the other running groups (0.13 mm vs 0.11 mm). The cortical thickness, osteocyte lacunae occupancy rate in the whole femur, numbers of apoptotic osteocytes and osteoclastic resorption surfaces were not significantly different between groups. Statistical differences were occasionally noted depending on the femoral anatomical region.

CONCLUSION

These results suggest that the femur should not be considered as the better bone to study the effects of running protocols.

Prediction of Cortical Bone Thickness Variations in the Tibial Diaphysis of Running Rats

A cell-mechanobiological model is used for the prediction of bone density variation in rat tibiae under medium and high mechanical loads. The proposed theoretical-numerical model has only four parameters that need to be identified experimentally. It was used on three groups of male Wistar rats under sedentary, moderate intermittent and continuous running scenarios over an eight week period. The theoretical numerical model was able to predict an increase in bone density under intermittent running (medium intensity mechanical load) and a decrease of bone density under continuous running (higher intensity mechanical load). The numerical predictions were well correlated with the experimental observations of cortical bone thickness variations, and the experimental results of cell activity enabled us to validate the numerical results predictions. The proposed model shows a good capacity to predict bone density variation through medium and high mechanical loads. The mechanobiological balance between osteoblast and osteoclast activity seems to be validated and a foreseen prediction of bone density is made available.

Physical Activity and Bone Vascularization: A Way to Explore in Bone Repair Context?

Physical activity is widely recognized as a biotherapy by WHO in the fight and prevention of bone diseases such as osteoporosis. It reduces the risk of disabling fractures associated with many comorbidities, and whose repair is a major public health and economic issue. Bone tissue is a dynamic supportive tissue that reshapes itself according to the mechanical stresses to which it is exposed. Physical exercise is recognized as a key factor for bone health. However, the effects of exercise on bone quality depend on exercise protocols, duration, intensity, and frequency. Today, the effects of different exercise modalities on capillary bone vascularization, bone blood flow, and bone angiogenesis remain poorly understood and unclear. As vascularization is an integral part of bone repair process, the analysis of the preventive and/or curative effects of physical exercise is currently very undeveloped. Angiogenesis–osteogenesis coupling may constitute a new way for understanding the role of physical activity, especially in fracturing or in the integration of bone biomaterials. Thus, this review aimed to clarify the link between physical activities, vascularization, and bone repair.

Preventive Moderate Continuous Running-Exercise Conditioning Improves the Healing of Non-Critical Size Bone Defects in Male Wistar Rats: A Pilot Study Using µCT

Although physical exercise has unquestionable benefits on bone health, its effects on bone healing have been poorly investigated. This study evaluated the effects of preemptive moderate continuous running on the healing of non-critical sized bone defects in rats by µCT. We hypothesized that a preemptive running exercise would quicken bone healing. Twenty 5-week-old, male, Wistar rats were randomly allocated to one of the following groups (n = 10): sedentary control (SED) or continuous running (EX, 45 min/d, 5 d/week at moderate speed, for 8 consecutive weeks). A 2 mm diameter bone defect was then performed in the right tibia and femur. No exercise was performed during a 4 week-convalescence. Healing-tissue trabecular microarchitectural parameters were assessed once a week for 4 weeks using µCT and plasma bone turnover markers measured at the end of the study protocol (time point T12). At T12, bone volume fraction (BV/TV; BV: bone volume, TV: tissue volume) of the healing tissue in tibiae and femurs from EX rats was higher compared to that in SED rats (p = 0.001). BV/TV in EX rats was also higher in tibiae than in femurs (p < 0.01). The bone mineral density of the healing tissue in femurs from EX rats was higher compared to that in femurs from SED rats (p < 0.03). N-terminal telopeptide of collagen type I in EX rats was decreased compared to SED rats (p < 0.05), while no differences were observed for alkaline phosphatase and parathyroid hormone. The study provides evidence that preemptive moderate continuous running improves the healing of non-critical sized bone defects in male Wistar rats.

Does Physical Exercise Always Improve Bone Quality in Rats?

For decades, the osteogenic effect from different physical activities on bone in rodents remained uncertain. This literature review presents for the first time the effects on five exercise models (treadmill running, wheel running, swimming, resistance training and vibration modes) in three different experimental rat groups (males, females, osteopenic) on bone quality. The bone parameters presented are bone mineral density, micro-architectural and mechanical properties, and osteoblast/osteocyte and osteoclast parameters. This review shows that physical activities have a positive effect (65% of the results) on bone status, but we clearly observed a difference amongst the different protocols. Even if treadmill running is the most used protocol, the resistance training constitutes the first exercise model in term of osteogenic effects (87% of the whole results obtained on this model). The less osteogenic model is the vibration mode procedure (31%). It clearly appears that the gender plays a role on the bone response to swimming and wheel running exercises. Besides, we did not observe negative results in the osteopenic population with impact training, wheel running and vibration activities. Moreover, about osteoblast/osteocyte parameters, we conclude that high impact and resistance exercise (such jumps and tower climbing) seems to increase bone formation more than running or aerobic exercise. Among the different protocols, literature has shown that the treadmill running procedure mainly induces osteogenic effects on the viability of the osteocyte lineage in both males and females or ovariectomized rats; running in voluntary wheels contributes to a negative effect on bone metabolism in older male models; whole-body vertical vibration is not an osteogenic exercise in female and ovariectomized rats; whereas swimming provides controversial results in female models. For osteoclast parameters only, running in a voluntary wheel for old males, the treadmill running program at high intensity in ovariectomized rats, and the swimming program in a specific ovariectomy condition have detrimental consequences.

Does eccentric-concentric resistance training improve early functional outcomes compared to concentric resistance training after total knee arthroplasty?

BACKGROUND

Total knee arthroplasty (TKA) is the preferred surgical treatment of end stage osteoarthritis of the knee. However, up to 20% of patients are dissatisfied after TKA. Moreover, kinesiophobia is negatively correlated with functional outcomes.

RESEARCH QUESTION

The aim of this study was to compare the effects of combined concentric-eccentric versus concentric program on muscular strength assessment and quality of life, after total knee arthroplasty in elderly people.

METHOD

A prospective study including 20 subjects (72.1 ± 6.3 years), following a rehabilitation program after TKA was performed. Subjects were randomized in combined eccentricconcentric (ECC-CON, n = 10) versus concentric (CN, n = 10) early rehabilitation protocols. There were no significant differences between groups with respect to demographic data. Data were collected before and after protocol: performance-based physical function (timed up and go test, 10-meter walk test, isokinetic assessment), Selfreported physical function and quality of life (Lequesne-ISK, WOMAC, OAKHQOL) and kinesiophobia assessment (TSK-CF). The Gaussian distribution for the whole population of this study was tested by a Kolmogorov-Smirnov test. Statistical analysis was performed using non-parametric Mann-Whitney U or Fisher's exact probability test, as appropriate.

RESULTS AND CONCLUSION

Performance-based physical function tests showed a significant improvement after early rehabilitation in the ECC-CON group for timed up and go (p = 0.0002) and 10-meter walk test (p = 0.001). Operated hamstring muscle peak torque was significantly improved in the ECC-CON group (p = 0.03). Self-reported physical function and quality of life tests were significantly better in the ECC-CON group for ISK (p = 0.03) and WOMAC (p = 0.04). Self-reported kinesiophobia significantly decreased after rehabilitation in both groups (p = 0.01) whilst there were no differences between groups. Early combined eccentric-concentric rehabilitation after TKA appears to be associated with improved outcomes compared to classic concentric rehabilitation protocols, on both physical function and quality of life. This information is new. Assessment and care of kinesiophobia should be considered in rehabilitation protocols standards.

Use of adult mesenchymal stromal cells in tissue repair: impact of physical exercise

Physical exercise (PE) has unquestionable beneficial effects on health, which likely extend into several organ-to-cell physiological processes. At the cell scale, endogenous mesenchymal stromal cells (MSCs) contribute to tissue repair, although their repair capacities may be insufficient in paucicellular or severely damaged tissues. For this reason, MSC transplantation holds great promise for tissue repair. With the goals of understanding if PE has beneficial effects on MSC biology and if PE potentiates their role in tissue repair, we reviewed literature reports regarding the effects of PE on MSC properties (specifically, proliferation, differentiation, and homing) and of a combination of PE and MSC transplantation on tissue repair (specifically neural, cartilage, and muscular tissues). Contradictory results have been reported; interpretation is complicated because various and different species, cell sources, and experimental protocols, specifically exercise programs, have been used. On the basis of these data, the effects of exercise on MSC proliferation and differentiation depend on exercise characteristics (type, intensity, duration, etc.) and on the characteristics of the tissue from which the MSCs were collected. For the in vitro studies, the level of strain (and other details of the mechanical stimulus), the time elapsed between the end of exposure to strain and MSC collection, the age of the donors, as well as the passage number at which the MSCs are evaluated also play a role. The combination of PE and MSC engraftment improves neural, cartilage, and muscular tissue recovery, but it is not clear whether the effects of MSCs and exercise are additive or synergistic.

Intense bone fluorescence reveals hidden patterns in pumpkin toadlets

The phenomenon of fluorescence can be used by animals to change effective colouration or patterning, potentially to serve functions including intra- and interspecific signalling. Initially believed to be restricted to marine animals, fluorescent colours are now being described in an increasing number of terrestrial species. Here, we describe unique, highly fluorescent patterns in two species of pumpkin toadlets (Brachycephalus ephippium and B. pitanga). We establish that the origin of the fluorescence lies in the dermal bone of the head and back, visible through a particularly thin skin. By comparing them to those of the closely related species Ischnocnema parva, we demonstrate that pumpkin toadlets' bones are exceptionally fluorescent. We characterize the luminescence properties of the toadlets' bones and discuss the potential function of fluorescent patterns in natural lighting conditions.

Quick benefits of interval training versus continuous training on bone: a dual-energy X-ray absorptiometry comparative study

To delay age-related bone loss, physical activity is recommended during growth. However, it is unknown whether interval training is more efficient than continuous training to increase bone mass both quickly and to a greater extent. The aim of this study was to compare the effects of a 10-week interval training regime with a 14-week continuous training regime on bone mineral density (BMD). Forty-four male Wistar rats (8 weeks old) were separated into four groups: control for 10 weeks (C10), control for 14 weeks (C14), moderate interval training for 10 weeks (IT) and moderate continuous training for 14 weeks (CT). Rats were exercised 1 h/day, 5 day/week. Body composition and BMD of the whole body and femur respectively were assessed by dual-energy X-ray absorptiometry at baseline and after training to determine raw gain and weight-normalized BMD gain. Both trained groups had lower weight and fat mass gain when compared to controls. Both trained groups gained more BMD compared to controls when normalized to body weight. Using a 30% shorter training period, the IT group showed more than 20% higher whole body and femur BMD gains compared to the CT. Our data suggest that moderate IT was able to produce faster bone adaptations than moderate CT.

Does running strengthen bone?

Bone is a living tissue needing mechanical stress to maintain strength. Traditional endurance exercises offer only modest effects on bone. Walking and running produce low impact but lead to bone fatigue. This article is specifically addressed to therapists and explains the mechanisms involved for the effects of exercise on bone. Intermittent exercise limits bone fatigue, and downhill exercises increase ground impact forces and involve eccentric muscle contractions, which are particularly osteogenic.

Effect of the alcohol consumption on osteocyte cell processes: a molecular imaging study

We have previously shown microarchitectural tissue changes with cellular modifications in osteocytes following high chronic alcohol dose. The aim of this study was to assess the dose effect of alcohol consumption on the cytoskeleton activity, the cellular lipid content and modulation of differentiation and apoptosis in osteocyte. Male Wistar rats were divided into three groups: Control (C), Alcohol 25% v/v (A25) or Alcohol 35% v/v (A35) for 17 weeks. Bone mineral density (BMD) was assessed by DXA, osteocyte empty lacunae, lacunae surface, bone marrow fat with bright field microscopy. Osteocyte lipid content was analysed with transmission electron microscopy (TEM) and epifluorescence microscopy. Osteocyte apoptosis was analysed with immunolabelling and TEM. Osteocyte differentiation and cytoskeleton activity were analysed with immunolabelling and real time quantitative PCR. At the end of the protocol, BMD was lower in A25 and A35 compared with C, while the bone marrow lipid content was increased in these groups. More empty osteocyte lacunae and osteocyte containing lipid droplets in A35 were found compared with C and A25. Cleaved caspase-3 staining and chromatin condensation were increased in A25 and A35 versus C. Cleaved caspase-3 was increased in A35 versus A25. CD44 and phosphopaxillin stainings were higher in A35 compared with C and A25. Paxillin mRNA expression was higher in A35 versus A25 and C and sclerostin mRNA expression was higher in A35 versus C. We only observed a dose effect of alcohol consumption on cleaved caspase-3 osteocyte immunostaining levels and on the number of lipid droplets in the bone marrow.

Bone mineral density, hip bone geometry, and calcaneus trabecular bone texture in obese and normal-weight children

Our study aimed at comparing bone mineral density (BMD), geometric indices of hip bone strength, and indices of trabecular bone texture at the calcaneus in obese and normal-weight children. Fifty-three obese children (10.3 ± 1.4 yr) and 24 normal-weight children (10.4 ± 1.5 yr) participated in this study. Body composition, bone mineral content, and BMD at whole body (WB), lumbar spine (L2-L4), total forearm, and proximal femur (total hip [TH] and femoral neck [FN]) were measured by dual-energy X-ray absorptiometry (DXA). Bone geometry of the hip was evaluated by the hip structure analysis (HSA) program. DXA scans were analyzed at the FN at its narrowest region and the femoral shaft (FS) by the HSA program. Cross-sectional area (CSA) and section modulus (Z) were measured from hip BMD profiles. Texture analysis was performed on digitized radiographs of the calcaneus to assess trabecular bone microarchitecture, and the result was expressed as Hmean. WB BMD, L2-L4 BMD, TH BMD, and FN BMD were significantly higher in obese children compared with normal-weight peers (p < 0.05). FN Z and FS Z were not significantly different between the 2 groups, whereas Hmean parameter was significantly lower in obese children compared with normal-weight peers (p < 0.001). After adjustment for body weight, obese children displayed lower WB BMD, FN CSA, FN Z, FS CSA, and FS Z compared with normal-weight children. This study suggests that BMD of WB and geometric indices of hip bone strength are not adapted to the increased body weight in obese children.

Lipid peroxidation in judoists using oral contraceptives

12 female judoists using oral contraceptives (OCU) containing 0.03 mg ethinylestradiol and 3 mg drospirenone for 20 ± 12 months (mean ± SD) were compared with a control group of 14 judoist noncontraceptive users (NCU) in order to evaluate resting (T1) and postexercise (T2) lipid peroxidation (LPO) and antioxidant parameters. Data were collected 20 min before and 10 min after a morning session of judo training and included determination of lag phase (Lp) before free radical-induced oxidation, glutathione peroxidase (GPx), α-tocopherol, retinol, and oxidative stress markers related to LPO. Significantly higher resting oxidative stress (+125.8 and +165.2% for malondialdehyde and lipid peroxides, respectively) and lower values of Lp and GPx (-23.4 and -12.1%, respectively) were observed in the OCU compared with NCU. The judo training session induced an increase in plasma LPO whatever the treatment. We noted significant increases in Lp (+14.7%; p<0.05 vs. preexercise) and GPx (22.1%; p<0.05 vs. preexercise) only in the NCU group. We suggest that a judo training session favourably altered some antioxidants in NCU but not in OCU. As excessive oxidative stress is linked to the development of several chronic diseases, the use of agents to reduce antioxidants may be reasonable in OCU.

Lecturing to 200 students and its effects on cytokine concentration and salivary markers of adrenal activation

Stress not only activates the SAM system and the hypothalamic-pituitary-adrenal axes, but also the immune system. The aims of this study are to assess the physiological variations in saliva (cytokines, cortisol and alpha-amylase) and perceived stress in professors when they had to lecture to 200 students. A total of eight unstimulated saliva samples were collected from nine professors: four on a working day that included the lecture and four controls on a working day without a lecture. The professors also rated subjective stress on a seven-point scale 5 min before the lecture, immediately after the lecture and at the same times on the control day. The lecture elicited substantial increases in subjective stress ratings, with the values on the lecture day significantly higher than those on the control day. Lecturing resulted in significant increases in Tumor Necrosis Factor (TNF)-α, Interleukin (IL)-2 and IL-4 concentrations, but did not affect the IL-10 values. These changes appeared to be concomitant with changes in the concentrations of the stress markers, alpha-amylase and cortisol. The mechanisms by which psychosocial stress can induce cytokine changes and modify the activity of salivary alpha-amylase are not entirely understood, and further research is thus warranted.

[Nasopharyngeal carriage, antibiotic susceptibility and serotyping of Streptococcus pneumoniae and Haemophilus influenzae in children attending day care centers]

The aim of this study was to investigate the nasal carriage of Streptococcus pneumoniae (SP) and Haemophilus influenzae (HI) in children.

METHODS

Nasal samples were swabbed from children 3 months to 3 years of age, between December 2006 and April 2007, in 10 day-care centers in Dijon.

RESULTS

Three hundred and eighty-five children, 22.7 ± 8.4 months, were included. All were vaccinated against H1 and 92% had received at least one dose of PCV7 vaccine. HI colonization (55%) was associated with young age and concomitant pneumococcal carriage (52.4% vs. 39%). Amoxicillin/clavulanate and cefotaxime resistance rates were 17% and 0.5%. Pneumococcal carriage (48%) was increased in case of prior hospitalization. The rate of PDSP, 50%, was increased in case of recent infection (91% vs. 81%), previous antibiotherapy (64% vs. 41%), and decreased if PCV7 was completed (40.2% vs. 61,8%). There was no resistance to amoxicillin. The erythromycin resistance rate was 50.5%. 15% of the strains were vaccinal serotypes. Thirty-six and 41% of the strains were related and non-related to vaccine serotypes. Twenty-four and 11.6% of the strains were serotypes 19A and 6A respectively.

CONCLUSION

Over the last 10 years the global antibiotic resistance in children decreased for SP (22.9%) but nasal colonization remained stable due to the increase of some serotypes, such as 19A, most often resistant to antibiotics. The vaccine effectiveness against HI is optimal since no HIb serotypes were detected; resistance to betalactam is currently due equally to enzymatic mechanism and alteration of protein binding penicillin.

Effects of 6 weeks of n-3 fatty acids and antioxidant mixture on lipid peroxidation at rest and postexercise

The purpose of this randomized study was to measure the influence of 6 weeks of LCPUFA (600 mg EPA and 400 mg DHA per day) supplementation alone or in association with 30 mg vitamin E, 60 mg vitamin C and 6 mg β-carotene on resting and exercise-induced lipid peroxidation in judoists (n = 36). Blood samples were collected at rest before (T (1)) and after the supplementation period, in preexercise (T (2)) and postexercise (T (3)) conditions, for analysis of α-tocopherol, retinol, lag phase (Lp) before free radical-induced oxidation, maximum rate of oxidation (R (max)) during the propagating chain reaction, maximum amount of conjugated dienes (CD(max)) accumulated after the propagation phase, and nitric oxide, malondialdehyde and lipoperoxide (POOL) concentrations. Dietary data were collected using a 7-day diet record. There were no significant differences among treatment groups with respect to habitual intakes of energy from fat, carbohydrate, or protein. At T (1), there were no significant differences among treatment groups with respect to lipid peroxidation, lag phase, and levels of α-tocopherol or retinol. The consumption of an n-3 LC PUFA supplement increased oxidative stress at rest and did not attenuate the exercise-induced oxidative stress. The addition of antioxidants did not prevent the formation of oxidation products at rest. On the contrary, it seems that the combination of antioxidants added to the n-3 LCPUFA supplement led to a decrease in, CD(max), R (max), and POOL and MDA concentrations after a judo training session.

Health-related quality of life and patient–provider relationships in HIV-infected patients during the first three years after starting PI-containing antiretroviral treatment

The aim of this study was to investigate factors associated with better health-related quality of life (HRQL) during the first three years after starting PI-containing antiretroviral treatment. Clinical, social and behavioural data from the APROCO cohort enabled us to analyze simultaneously the association between HRQL and patients' relationships with their health care providers. A self-administered questionnaire collected information about HRQL (MOS-SF36) and relationships with medical staff (trust and satisfaction with information). Two aggregate scores, the physical (PCS) and mental (MCS) component summaries (adjusted for baseline HRQL), were used as dependent variables in the linear regressions to identify factors associated with HRQL. We had complete longitudinal data for 360 of the 611 patients followed through M36. Factors independently associated with a high MCS were (male) gender, no more than one change in treatment, (few) self-reported symptoms and trust in the physician. Factors independently associated with high PCS levels were employment, no children, (few) self-reported symptoms and satisfaction with the information and explanations provided by the medical staff. These results underline the need to improve patient-provider relationships to optimize long-term HRQL. Socio-behavioural interventions should focus on this goal.

Effect of lecturing to 200 students on heart rate variability and alpha-amylase activity

The aim of this study was to examine cardiovascular [heart rate variability (HRV)] and autonomic nervous system activation (by evaluating salivary alpha-amylase activity) that occur in professors both to, and after, the delivery of a lecture to 200 students and to determine whether gender is an influencing factor upon response. Fifty-two participants (26 women and 26 men) collected eight unstimulated saliva samples on 2 days (one a working day on which the lecture was given, the other a non-work or rest day). They also completed the Trait version of the State-Trait Anxiety Inventory (STAI) to assess their dispositional anxiety on the rest day and the State section of the STAI 15 min before and 10 min after their lecture, repeated at the same hour on the control (rest) day. The Perceived Stress Scale (PSS) was also recorded 15 min before the lecture. Continuous RR intervals were recorded before and after the lecture and the following HRV parameters were calculated: total spectral power (P (TOT)); the spectral power of the low frequency component (P (LF)); the high frequency component (P (HF)); and the ratio LF/HF. A reduction (P < 0.05) in the HF and HFnu component of HRV and an increase in the LH/HF ratio (P < 0.05) were observed at the end of the lecture. AA activity measured on the teaching day was significantly higher than that noted on the resting day. Lecturing resulted in a significant increase in the secretion of the stress marker alpha-amylase. Men and women did not differ in trait and state anxiety and no gender differences for HRV or AA activity were found.

Non-Hodgkin's lymphoma of the heart in patients infected with human immunodeficiency virus

A case of HIV-associated cardiac non-Hodgkin's lymphoma (NHL) is described, and the epidemiologic and clinicopathologic features of 21 cases previously reported in the literature are analyzed. All patients were homosexual males, and the cardiac NHL was the first acquired immune deficiency syndrome-defining condition in the majority. Patients were referred with nonspecific clinical findings including dyspnea and tachycardia, but rapid progression of cardiac dysfunction was frequent after symptoms appeared. Echocardiography constitutes the most useful noninvasive procedure in the diagnosis of cardiac NHL. Most of the patients had disseminated diseased at initial presentation; pathologically, the lymphomas were of B lymphocyte origin and of high-grade subtypes. Prognosis of HIV-associated cardiac NHL is generally poor, although clinical remission has been observed with combination chemotherapy. Cardiac lymphomas in HIV-associated patients are typically high-grade and often disseminate early. Although the prognosis is poor, patients in whom dissemination has not occurred could have longer survival under systemic chemotherapy.

Salbutamol intake and substrate oxidation during submaximal exercise

In order to test the hypothesis that salbutamol would change substrate oxidation during submaximal exercise, eight recreationally trained men twice performed 1 h at 60% VO(2) peak after ingestion of placebo or 4 mg of salbutamol. Gas exchange was monitored and blood samples were collected during exercise for GH, ACTH, insulin, and blood glucose and lactate determination. With salbutamol versus placebo, there was no significant difference in total energy expenditure and substrate oxidation, but the substrate oxidation balance was significantly modified after 40 min of exercise. ACTH was significantly decreased with salbutamol during the last 10 min of exercise, whereas no difference was found between the two treatments in the other hormonal and metabolic parameters. The theory that the ergogenic effect of salbutamol results from a change in substrate oxidation has little support during relatively short term endurance exercise, but it is conceivable that longer exercise duration can generate positive findings.

Effects of branched-chain amino acids supplementation on physiological and psychological performance during an offshore sailing race

The aim of the present study was to investigate the effect of protein diets, rich in branched chain amino acids (BCAA) on perceived exertion, mental and physical performance during an offshore sailing race that lasted 32 h. Twelve sailors were randomly allocated into one of two groups [Control (CON) and BCAA: n = 6/group]. The BCAA group consumed a standard diet of 11.2 MJ day(-1) (58% carbohydrate, 30% fat, 12% Protein) along with a high-protein supplement of 1.7 MJ day(-1) (40% carbohydrate, 35% protein, 25% fat) and 1.7 MJ day(-1) composed of 50% valine, 35% leucine, and 15% isoleucine. CON was given a standard diet of 14.5 MJ day(-1) (58% carbohydrate, 30% fat and 12% protein). During the race, heart rate was monitored. Subjects self-evaluated their feeling of fatigue every 3 h, and 12 samples of saliva from each subject were collected to perform cortisol assays. Before and after the race a vertical jump and a handgrip test were performed, and mental performance was evaluated with a standardized battery of tests. A significant increase in the feeling of fatigue was noted on the second day (D2) of race in both groups; the increase was higher in CON (P < 0.05). For both groups, salivary cortisol concentration followed a nycthemeral rhythm, with an alteration during the race as evidenced by high midnight cortisol levels between D1 and D2, and significantly decreased cortisol levels observed on D2 (P < 0.05). There was no change in physical performance at the end of the race in both groups. As a significant decrease (P < 0.05) in short-term memory performance was observed only in the CON group. These data indicate that an offshore sailing race enhances the feeling of fatigue, and decreases short-term memory performance. These detrimental consequences are reduced by a high-protein diet with BCAA.

Effects of short-term prednisolone intake during submaximal exercise

PURPOSE

To examine the prednisolone's ergogenic and metabolic effects during submaximal exercise.

METHODS

Ten recreational male athletes completed two cycling trials at 70-75% peak O2 consumption until exhaustion after either placebo (Pla, lactose) or oral prednisolone (Pred, 60 mg.d(-1) for 1 wk) treatment, according to a double-blind and randomized protocol. Blood samples were collected at rest and during exercise and recovery to determine ACTH, growth hormone (GH), prolactin (PRL), DHEA, insulin, blood glucose, and blood lactate values.

RESULTS

Time of cycling was significantly increased after chronic Pred treatment (Pred: 74.5+/-9.5 min; Pla: 46.1+/-3.3 min, P<0.01). Pred intake significantly lowered basal, exercise, and recovery ACTH, DHEA, and PRL concentrations, whereas GH concentrations were significantly lowered by Pred after 30 min of exercise. Blood glucose and insulin were significantly (P<0.05) increased by Pred during the whole experiment and until 30 min of exercise. Blood lactate concentrations were higher after Pred versus Pla at 10 min of exercise until 10 min of recovery (P<0.05).

CONCLUSION

From these data, short-term Pred intake did seem to significantly improve performance during submaximal exercise, with concomitant alterations in hormonal and metabolic responses. Further studies will be necessary to elucidate the mechanisms of these hormonal and metabolic changes, and to determine whether the changes may be associated with the marked performance improvement obtained.

Short-term glucocorticoid intake combined with intense training on performance and hormonal responses

OBJECTIVE

To investigate the effects of short-term prednisolone ingestion combined with intense training on exercise performance, hormonal (adrenocorticotrophic hormone (ACTH), prolactin, luteinising hormone (LH), growth hormone (GH), thyroid-stimulating hormone (TSH), dehydroepiandrosterone (DHEA), testosterone, insulin) and metabolic parameters (blood glucose, lactate, bicarbonate, pH).

METHODS

Eight male recreational athletes completed four cycling trials at 70-75% peak O(2) consumption until exhaustion just before (1) and after (2) either oral placebo or prednisolone (60 mg/day for 1 week) treatment coupled with standardised physical training (2 hours/day), according to a double-blind and randomised protocol. Blood samples were collected at rest, during exercise and passive recovery for the hormonal and metabolic determinations.

RESULTS

Time of cycling was not significantly changed after placebo but significantly increased (p<0.05) after prednisolone administration (50.4 (6.2) min for placebo 1, 64.0 (9.1) min for placebo 2, 56.1 (9.1) min for prednisolone 1 and 107.0 (20.7) min for prednisolone 2). There was no significant difference in any measured parameters after the week of training with placebo but a decrease in ACTH, DHEA, PRL, GH, TSH and testosterone was seen with prednisolone treatment during the experiment (p<0.05). No significant change in basal, exercise or recovery LH, insulin, lactate, pH or bicarbonate was found between the two treatment, but blood glucose was significantly higher under prednisolone (p<0.05) at all time points.

CONCLUSION

Short-term glucocorticoid administration induced a marked improvement in endurance performance. Further studies are needed to determine whether these results obtained in recreational male athletes maintaining a rigorous training schedule are gender-dependent and applicable to elite athletes.

Limitation of exercise capacity in nucleoside-treated HIV-infected patients with hyperlactataemia

BACKGROUND

Inhibition of DNA polymerase gamma by nucleoside reverse transcriptase inhibitors (NRTIs) can cause mitochondrial dysfunction and cellular toxicity. Hyperlactataemia, which is a consequence of a shift in the metabolism of pyruvate, is an indicator of nucleoside-related mitochondrial toxicity.

METHODS

We evaluated exercise and oxidative capacities as well as circulatory and ventilatory responses to exercise in 24 HIV-infected patients on NRTIs presenting hyperlactataemia [mean (+/-standard deviation) fasted lactate=3.5+/-1.1 mmol/L]; 27 NRTI-treated patients with normal baseline lactate concentrations were used as controls (mean fasted lactate=1.6+/-0.3 mmol/L).

RESULTS

In the patients with hyperlactataemia, the average peak work capacity (1.7+/-0.6 W/kg) and peak oxygen consumption (VO(2)) (21+/-4 mL/kg/min) were significantly lower (P<0.01) than in control subjects (work, 2.1+/-0.4 W/kg; VO(2), 25+/-4 mL/kg/min). The capacity to increase oxygen extraction during exercise was significantly diminished in the hyperlactataemia group, as shown by a low peak systemic arteriovenous oxygen difference (a-vO(2)) difference compared with controls (11+/-3 vs 14+/-3 mL/dL; P=0.008), and as indicated by a linear correlation between VO(2) and systemic a-vO(2) difference (r(2)=0.76). During exercise, the increases in cardiac output relative to VO(2) (mean Delta cardiac output (Q)/DeltaVO(2)=8+/-3.6) and ventilation (mean Delta ventilation (VE)/DeltaVO(2)=48.6+/-13.2) were significantly higher in hyperlactataemia patients compared with controls (mean cardiac output Delta(Q)/DeltaVO(2)=6+/-2; mean DeltaVE/DeltaVO(2)=42+/-12.7; P=0.03).

CONCLUSIONS

The degree of exercise limitation in patients with nucleoside-related mitochondrial toxicity correlates directly with the severity of impaired muscle oxidative phosphorylation, as indicated by the capacity for muscle oxygen extraction. Exaggerated circulatory and ventilatory responses to exercise are direct consequences of the level of impaired muscle oxidative phosphorylation.

Effects of acute prednisolone intake on substrate utilization during submaximal exercise

We examined the hypothesis that acute therapeutic glucocorticoid intake could change the contribution of fat and carbohydrate (CHO) in energy production during exercise. Nine healthy recreationally-trained male subjects twice performed submaximal exercise (60 min at 60 % VO2max) after ingestion of placebo (Pla) or 20 mg of prednisolone (Pred), according to a double blind and randomized protocol. Respiratory exchange was monitored during exercise and blood samples were collected at rest, every 10 min during exercise and after 5, 10, and 20 min of passive recovery. Pred intake significantly increased total energy expenditure during exercise, but CHO oxidation was lower and fat oxidation higher after Pred vs. Pla. ACTH and IL-6 concentrations were significantly decreased with Pred during exercise, whereas no variations were found in GH, insulin, blood glucose, and lactate between the 2 treatments. In conclusion, it appears that acute prednisolone systemic administration does reduce total carbohydrate oxidation during submaximal exercise. Further studies are necessary to clarify the mechanisms involved and to determine whether this modification in the substrate oxidation balance under glucocorticoid administration in recreationally-trained male subjects could result in a competitive advantage in elite athletes.

Effects of acute prednisolone administration on exercise endurance and metabolism

OBJECTIVE

To examine whether acute glucocorticoid (GC) intake alters performance and selected hormonal and metabolic variables during submaximal exercise.

METHODS

In total, 14 recreational male athletes completed two cycling trials at 70-75% maximum O(2) uptake starting 3 h after an ingestion of either a lactose placebo or oral GC (20 mg of prednisolone) and continuing until exhaustion, according to a double-blind randomised protocol. Blood samples were collected at rest, after 10, 20, 30 minutes, and at exhaustion and recovery for measurement of growth hormone (GH), adrenocorticotropic hormone (ACTH), dehydroepiandrosterone (DHEA), prolactin, insulin, blood glucose, lactate and interleukin (IL)-6 determination.

RESULTS

Cycling duration was not significantly changed after GC or placebo administration (55.9 (5.2) v 48.8 (2.9) minutes, respectively). A decrease in ACTH and DHEA (p<0.01) was observed with GC during all of the experiments and in IL-6 after exhaustion (p<0.05). No change in basal, exercise or recovery GH, prolactin, insulin or lactate was found between the two treatments but blood glucose was significantly higher with GC (p<0.05) at any time point.

CONCLUSION

From these data, acute systemic GC administration does seem to alter some metabolic markers but did not influence performance during submaximal exercise.

[Vaccination status of Burgundy inhabitants: a survey in various institutions]

AIM

The authors had for aim to determine the vaccination coverage in Burgundy. This study was based on data collection from institutions either in charge of vaccination or controlling the vaccination coverage of given target populations.

METHOD

The concerned institutions were asked to provide a representative sample of the population controlled between September 2000 and June 2001 and a longitudinal study was carried out on the data. The analysis of vaccination coverage was made by institution and included i) the rate of people carrying a document proving their vaccination, ii) the rate of minimal vaccination coverage, and iii) the rate of maximal vaccination coverage.

RESULTS

4,159 people participated in the study. The analysis revealed that, on the first university medical follow-up, young people rarely carried a vaccination certificate. This rate increased in occupational medicine and in healthcare institutions. The minimum rates of vaccination coverage against tetanus strongly decreased for population of over 60 years of age (39.6%), and adults living in precariousness (44.3%). In occupational medicine, 34.2% of women ignored their vaccinal status against rubella, almost 10% said that they had not contracted the disease and were not vaccinated.

CONCLUSION

This survey confirmed the urgent need to improve the vaccination coverage against tetanus for people over 60 years of age, and vaccination against rubella for women of reproductive age. It also demonstrated the need to provide adults with an appropriate vaccination file allowing recording and saving their respective vaccination status.

Effects of acute salbutamol intake during supramaximal exercise in women

OBJECTIVE

To study the effects of an acute therapeutic oral intake of beta(2) agonist on performance and substrate response during supramaximal exercise in women.

METHODS

12 healthy moderately trained female volunteers performed a Wingate test after ingestion of placebo (Pla) and salbutamol (Sal; 4 mg) according to a double-blind randomised crossover study. Blood samples were collected at rest, at the end of exercise and after 5 (r5), 10 (r10) and 15 (r15) min of passive recovery for adrenocorticotropic hormone (ACTH), growth hormone (GH), insulin, blood glucose and lactate measurements.

RESULTS

Peak power (PP) and mean power (MP) significantly increased whereas time to peak power was significantly shorter with Sal than with Pla (p<0.05). No change was observed in the fatigue index. ACTH was not significantly modified but r15 growth hormone significantly decreased (p<0.05) after the intake of Sal. Both blood INS and blood glucose were significantly increased by the intake of Sal during all the experiments (p<0.01). Blood lactate was significantly increased by the intake of Sal compared with that of Pla (p<0.05) after 10 and 15 min of passive recovery.

CONCLUSION

From these data, acute therapeutic oral intake of Sal seems to induce, irrespective of the subjects' gender, an improvement in performance during a supramaximal exercise--that is, increase in PP and MP. Further studies are necessary to clarify whether the mechanisms involved in the response to intake of Sal are linked to central and/or peripheral pathways.

Effects of acute prednisolone intake during intense submaximal exercise

To study the effects of a therapeutical dose of corticosteroid alone or associated with beta-2 agonist on performance and substrate response during intense submaximal exercise, seven healthy moderately trained male volunteers participated in the double-blind randomized cross-over study. An intense endurance exercise test to exhaustion was performed after ingestion of placebo (Pla), 20 mg prednisolone (Pred), and 20 mg prednisolone plus 4 mg salbutamol (Pred-Sal). Blood samples were collected at rest, after 5, 10 min of exercise, at exhaustion, and after 5 (r5), 10 (r10), and 20 (r20) min of passive recovery for ACTH, growth hormone, insulin, blood glucose, and lactate measurements. There were no significant differences in exercise time to exhaustion between the three treatments (Pla: 21.5 +/- 2.9; Pred: 22.0 +/- 2.5; Pred-Sal: 24.2 +/- 2.8 min). ACTH was significantly lowered after Pred and Pred-Sal vs. Pla from the start of exercise to the end of the experiment (p < 0.05). Pred and Pred-Sal increased resting and recovery (r10 and r20) significantly but not exercise blood glucose values. There were no significant differences in growth hormone concentrations between the three treatments whereas insulin was significantly higher at rest, during exercise, and at r20 after Pred-Sal administration vs. Pred and Pla (p < 0.05). Pred and Pred-Sal showed no significant effect on blood lactate compared with Pla treatment. These preliminary results do not support the hypothesis that acute oral therapeutic corticosteroid intake alone or associated with beta-2 mimetic improves performance during intense submaximal exercise, but further studies are necessary with tests of longer duration.

Les abcès pyogènes secondaires du psoas : à propos de six cas et revue de la littérature

PURPOSE

Psoas abscess is a rare disease in developed countries. Its diagnosis is difficult and any delay could lead to a worsen prognosis. The aim of this study is to determine the best diagnostic and therapeutic practices.

METHODS

A retrospective study of psoas abscess that occurred during six months was performed.

RESULTS

Six cases of secondary psoas abscess are reported. They were associated with spondylodiscitis in three cases, arthritis and gynaecologic infection in the three remaining cases. Anatomic diagnosis was performed by tomodensitometry. Microbiologic diagnosis was obtained by blood culture or direct puncture of the abscess. Antibiotics were associated with percutaneous drainage in two cases, with simple puncture in one case, and with surgery in one case. A local improvement w observed in all cases. The oldest patients presented the worst complications which were not directly caused by the abscess.

CONCLUSION

Physicians must be aware of psoas abscess because of their increasing incidence. Despite the fact that digestive pathologies are the main cause of secondary psoas abscess, bone infections, particularly spine infections, should be taken into consideration. Tomodensitometry guided puncture or percutaneous drainage are of diagnostic and therapeutic interest. Infectious samples must be taken before starting antibiotics, which have to be efficient against Gram negative bacillus, anaerobes and Staphylococcus aureus. Surgery must be quickly performed when the primary infection localisation need it, in case of voluminous abscess or when antibiotics and drainage are inefficient.

Short term salbutamol ingestion and supramaximal exercise in healthy women

OBJECTIVE

To test the hypothesis that chronic salbutamol intake improves performance during supramaximal exercise and to estimate the effects of this treatment on body composition, bone mass, and metabolic indices in healthy women.

METHODS

Fourteen female volunteers (seven sedentary and seven recreationally trained) performed a 30 second Wingate test with and without salbutamol ingestion (12 mg/day for four weeks) in a random, double blind, crossover design. Blood samples were collected at rest, at the end of the test, and during passive recovery for lactate measurement. Body composition and bone mass were determined by dual energy x ray absorptiometry.

RESULTS

Peak power appeared significantly earlier and was significantly (p<0.05) increased after salbutamol intake in all subjects. There was no difference in total work performed and fatigue indices with salbutamol compared with placebo. No significant alterations in lean or fat body mass and bone variables were observed with salbutamol treatment in either trained or untrained subjects during the trial. In contrast, blood lactate was significantly (p<0.05) increased during the recovery period after salbutamol ingestion compared with placebo.

CONCLUSION

As in men, chronic administration of therapeutic concentrations of salbutamol did not induce an anabolic effect in women but increased maximal anaerobic power. Further studies are necessary to clarify the mechanisms involved.

In-vivo impact of the MexXY efflux system on aminoglycoside efficacy in an experimental model of Pseudomonas aeruginosa pneumonia treated with tobramycin

Aminoglycosides are of major importance in treating Pseudomonas aeruginosa pneumonia (PAP). However, their efficacy may be compromised by low-level resistance caused by the inducible MexXY multidrug efflux pump. In the present study, the impact of the MexXY efflux pump was investigated in vivo in an experimental model of PAP in rabbits treated with intravenous tobramycin. Three strains were used to induce PAP in rabbits: PAO1 (wild-type strain; MIC 1 mg/L), mutant 11B (mexX::Tn501; no expression of MexXY; MIC 0.5 mg/L) and mutant MutGR1 (MexZ null; constitutive expression of MexXY; MIC 2 mg/L). Five hours after inoculation, treatment with tobramycin (10 mg/kg) was implemented (peak serum concentration 30 mg/L). The animals were killed humanely 48 h after inoculation, and the residual pulmonary bacterial concentration was determined. Selection of bacteria expressing MexXY was determined by plating lung homogenates on agar plates containing antibiotic. Mean bacterial counts (log(10) CFU/g) for treated vs. untreated rabbits were 6.26 and 8.13 (p < 0.0001), 6.00 and 8.38 (p < 0.001), and 7.25 and 8.79 (p 0.04) for PAO1, 11B and MutGR1, respectively, with an overall mortality rate of 0% vs. 8.9% (p < 0.01). MexXY-overexpressing bacteria were recovered from three (21%) treated rabbits. The C(max)/MIC ratio was the parameter that was best associated with tobramycin efficacy. The bacteria overexpressing MexXY, recovered from lung, occurred with a C(max)/MIC window of 19-26. It was concluded that the experimental PAP model highlights poor tobramycin bacteriological efficacy in vivo, contrasting with survival gain, and that the contribution of the MexXY system to this low level of tobramycin efficacy is modest. Finally, this model appears to be suitable for the investigation of new anti-pseudomonal therapeutic strategies.

Effects of Acute Salbutamol Intake During a Wingate Test

To investigate the impact of acute salbutamol intake on performance and selected hormonal and metabolic variables during supramaximal exercise, 13 recreational male athletes performed two 30-second Wingate tests after either placebo (PLA, lactose) or salbutamol (SAL, 4 mg) oral administration, according to a double-blind and randomized protocol. Blood samples collected at rest, end of the Wingate test, recovery (5, 10, 15 min) were tested for growth hormone (GH), insulin (INS), blood glucose (GLU), and lactate determination. We found the peak and mean power performed significantly increased after SAL vs. PLA (PPSAL: 896 +/- 46; PPPLA: 819 +/- 57 W; MPSAL: 585 +/- 27; MPPLA: 534 +/- 35 W, p < 0.05), whereas no change was observed in the fatigue index. Blood glucose and INS were significantly increased by SAL at rest, at the end of the Wingate test, and during the 5 first minutes of recovery (p < 0.05). Plasma GH was significantly decreased by SAL (p < 0.05) during the recovery whereas end-exercise and recovery blood lactate tended but were not significantly increased after SAL vs. PLA. From these data, acute salbutamol intake at therapeutical dosage did appear to improve peak power and mean power during a supramaximal exercise, but the mechanisms involved need further investigation.

Effects of Short-Term Salbutamol Ingestion During a Wingate Test

The effects of a chronic salbutamol intake (SAL, 12 mg/d during 3 weeks) on changes in body composition, metabolic indices and performance during a 30-second Wingate test were determined in 8 strength-trained male athletes (T) and 7 sedentary male (UT) subjects, according to a double-blind, randomized, cross-over protocol. Blood samples were collected both at rest, at the end of the test, and during passive recovery (5 min, 10 min, 15 min) for leptin (at rest), and blood lactate measurements. No significant changes in lean body mass, fat mass, and leptin were observed with SAL treatment in either group during the trial. Peak power was significantly increased (p < 0.05) after SAL intake in all subjects (T: 11.9 %; UT: 8.3 %) with a decrease in time to peak power with SAL compared to placebo (PLA) (p < 0.05). There was no change in total work performed and in fatigue indices with SAL compared to PLA. Blood lactate was significantly increased after SAL vs. PLA during the recovery (p < 0.05) in all subjects. The data demonstrate that the chronic administration of therapeutic levels of salbutamol increases maximal anaerobic power in man, irrespective of the subjects' training status. This study also rules out any implication of an anabolic effect in this improvement in performance during supramaximal exercise. Further studies are necessary to clarify the mechanisms involved.

Moxifloxacin monotherapy compared to amoxicillin-clavulanate plus roxithromycin for nonsevere community-acquired pneumonia in adults with risk factors

The objective of this study was to assess the efficacy and safety of moxifloxacin versus amoxicillin-clavulanate plus roxithromycin (comparator) in adult community-acquired pneumonia (CAP) patients with risk factors. In this comparative, randomized, multicenter, open-label study, patients hospitalized for CAP received a 10-day oral treatment with either moxifloxacin (400 mg o.d.) or amoxicillin-clavulanate (1,000/125 mg t.i.d.) plus roxithromycin (150 mg b.i.d.). Clinical and bacteriological outcomes were assessed during test of cure and follow-up visits (5-7 days and 21-28 days after the end of treatment, respectively). Of 349 randomized patients, 346 were included in the intent-to-treat analysis and 289 in the per-protocol analysis. Their baseline characteristics were comparable. The most frequent risk factors for mortality were age >65 years (50.0%), alcoholism (23.1%), and comorbidities (50.6%); chronic obstructive pulmonary disease (COPD) (25.4%) and diabetes mellitus (13.6%) were the most common associated comorbidities. A causative pathogen was documented in 66 of 346 (19.1%) of the patients (including 21 with positive blood cultures). Respective per-protocol clinical success rates at test-of-cure (primary efficacy endpoint) for moxifloxacin and comparator were 131 of 151 (86.8%) and 120 of 138 (87.0%), with a 95% confidence interval (CI) of -8.0-7.6 for the difference. Bacteriological success rates (eradication) were 23 of 30 (76.7%) and 23 of 31 (74.2%); rates for patients with positive blood cultures were 10 of 14 and 4 of 6. Persistent clinical success rates at follow-up were 118 of 120 (98.3%) and 102 of 106 (96.2%), with a 95%CI of -2.2-6.4 for the difference. The intent-to-treat analysis confirmed these results. Adverse events associated with moxifloxacin and the comparator drug were reported for 42 of 171 (24.6%) and 50 of 175 (28.6%) of the patients, respectively, and comprised predominantly digestive disorders, which occurred in 9.4% and 21.1%. On the basis of these results, once-daily oral moxifloxacin alone is as effective as amoxicillin-clavulanate plus roxithromycin for the treatment of CAP in patients with risk factors.

Serum adiponectin and metabolic parameters in HIV-1-infected patients after substitution of nevirapine for protease inhibitors

BACKGROUND

In the context of HIV infection and antiretroviral therapy, adiponectin concentrations have been shown to be related to lipodystrophy, metabolic alterations and HIV-protease inhibitor (PI) use. The replacement of PI by nevirapine has improved the lipid profile of patients under antiretroviral therapy. The aim of the present study was to examine whether adiponectin concentration or insulin sensitivity level correlate with the modifications of lipid parameters after the switch of PI by nevirapine.

MATERIAL AND METHODS

The evolution of metabolic parameters before and after 6 months of substitution of nevirapine for protease inhibitors was evaluated in a cohort of 55 HIV-1 infected patients. Adiponectin concentration, insulin sensitivity, lipid profile, cholesterol ester transfer protein (CETP) mass concentration and triglyceride enrichment of HDL were determined before and after the replacement of PI by nevirapine. Insulin sensitivity was evaluated by the HOMA model assessment.

RESULTS

Twenty-four weeks of treatment with nevirapine improved significantly the lipid profile with a significant reduction of apoB (from 0.98 to 0.92 g L(-1); P = 0.005) and triglyceride (from 2.02 to 1.66 mmol L(-1); P = 0.02). HDL cholesterol and apoA1 increased significantly (from 0.99 to 1.19 mmol L(-1); P = 0.001 and from 1.40 to 1.57 g L(-1); P < 0.001, respectively). The triglyceride enrichment of HDL significantly decreased after the replacement of PI by nevirapine (from 0.248 +/- 0.092 to 0.213 +/- 0.093; P = 0.003). At baseline, and after 24 weeks of nevirapine treatment, we observed significant correlations between adiponectin level and lipid parameters [(HDL-cholesterol (r = 0.66, P = 0.001 and r = 0.69, P = 0.001); triglycerides (r = -0.42, P = 0.002 and r = -0.57, P = 0.001), and triglyceride enrichment of HDL (r = -0.43, P = 0.005 and r = -0.53, P = 0.005)]. Twenty-four weeks of treatment with nevirapine did not significantly change adiponectin concentrations (from 984 to 1086 micro g L(-1), P = 0.22), CETP mass and insulin sensitivity.

CONCLUSION

This study shows that even though a strong correlation was found between adiponectin and some metabolic parameters at baseline and after 24 weeks of treatment by nevirapine, the improvement of lipid profile observed after the replacement of PI by nevirapine was not in relation to the change of plasma adiponectin concentration. The significant decrease of triglyceride enrichment of HDL after the replacement of PI by nevirapine probably leads to a decreased catabolism of HDL lipoprotein, and consequently explains the increase of plasma HDL concentration observed in this study.

[Is there an increased risk for cardiovascular disease in HIV-infected patients on antiretroviral therapy?]

There is a growing concern about an increased risk for cardiovascular disease in HIV infected patients receiving antiretroviral therapy (ART). This risk could be related to metabolic abnormalities associated with long-term use of antiretroviral drugs. In fact, well recognized cardiovascular risk factors such as hypertension, dyslipidaemia, diabetes mellitus and central fat deposition are increasingly seen in HIV patients on ART. These factors can also be associated with non reversible risk factors, such as male sex, age greater than 40 years and family history of premature coronary artery disease. In addition, cigarette smoking and sedentary lifestyle may predispose these patients to significant cardiovascular disease. A direct atherogenic effect of HIV infection itself or antiretroviral drugs is unlikely. Epidemiological studies have suggested an increased risk for coronary artery disease in HIV infected persons; nevertheless, only long term follow-up could confirm this statement. Despite these uncertainties, it seems reasonable to identify and manage cardiovascular risk factors in HIV infected patients.

LDL-receptors expression in HIV-infected patients: relations to antiretroviral therapy, hormonal status, and presence of lipodystrophy

BACKGROUND

Abnormalities in lipid levels and lipodystrophy (LD) have been commonly reported after commencement of highly active antiretroviral therapy (HAART). A major mechanism by which plasma low-density lipoprotein (LDL) cholesterol levels may be influenced is via the regulation of hepatic LDL receptor expression. The activity of LDL receptors is under hormonal control. Moreover, HIV infection and HAART are associated with important modifications of hormonal status. As the cause of these adverse reactions is unknown, the effects of HAART and lipodystrophy on LDL receptors were evaluated.

MATERIALS AND METHODS

Thirty-nine HIV treated patients (21 with a protease inhibitor (PI) containing regimen, 18 without PI use) and 22 control subjects were tested for insulin resistance (HOMA model assessment), lipid profile, serum concentration of dehydroepiandrosterone (DHEA) and LDL-R expression. LDL-R on mononuclear cells were quantified by flow cytrometry.

RESULTS

Among the 39 HIV infected patients, 14 patients had a lipodystrophy (LD). Patients with LD had significantly higher levels of triglyceride (TG) and insulin resistance compared to patients without LD. There was no significant difference in LDL-R count between patients with or without PI use. In contrast, LDL-R count was significantly lower in patients with LD compared with those without (8504 +/- 3901 vs. 13 200 +/- 4532, P = 0.001). There was no difference in LDL-R count between patients without LD and control subjects. Patients with LD had lower levels of DHEA compared to patients without LD. In HIV-infected patients, we found a significant correlation between LDL-R expression and TG (r = -0.32; P = 0.04) and LDL cholesterol (r = -0.33; P = 0.04). In contrast, we did not observe a correlation between DHEA level and LDL-R count or LDL cholesterol level.

CONCLUSIONS

HIV-lipodystrophy is associated with a lower expression of LDL-R. This decreased expression of LDL-R seems independent of DHEA or insulin secretion.