Aerobic exercise attenuates inducible TNF production in humans

The pulse of inflammation: heart rate variability, the cholinergic anti-inflammatory pathway and implications for therapy

Biological therapeutics targeting TNF, IL-1 and IL-6 are widely used for treatment of rheumatoid arthritis, inflammatory bowel disease and a growing list of other syndromes, often with remarkable success. Now advances in neuroscience have collided with this therapeutic approach, perhaps rendering possible the development of nerve stimulators to inhibit cytokines. Action potentials transmitted in the vagus nerve culminate in the release of acetylcholine that blocks cytokine production by cells expressing acetylcholine receptors. The molecular mechanism of this cholinergic anti-inflammatory pathway is attributable to signal transduction by the nicotinic alpha 7 acetylcholine receptor subunit, a regulator of the intracellular signals that control cytokine transcription and translation. Favourable preclinical data support the possibility that nerve stimulators may be added to the future therapeutic armamentarium, possibly replacing some drugs to inhibit cytokines.

Strategies for reducing body fat mass: effects of liposuction and exercise on cardiovascular risk factors and adiposity

Liposuction is the most popular aesthetic surgery performed in Brazil and worldwide. Evidence showing that adipose tissue is a metabolically active tissue has led to the suggestion that liposuction could be a viable method for improving metabolic profile through the immediate loss of adipose tissue. However, the immediate liposuction-induced increase in the proportion of visceral to subcutaneous adipose tissue could be detrimental to metabolism, because a high proportion of visceral to subcutaneous adipose tissue is associated with risk factors for cardiovascular disease. The results of studies investigating the effects of liposuction on the metabolic profile are inconsistent, however, with most studies reporting either no change or improvements in one or more cardiovascular risk factors. In addition, animal studies have demonstrated a compensatory growth of intact adipose tissue in response to lipectomy, although studies with humans have reported inconsistent results. Exercise training improves insulin sensitivity, inflammatory balance, lipid oxidation, and adipose tissue distribution; increases or preserves the fat-free mass; and increases total energy expenditure. Thus, liposuction and exercise appear to directly affect metabolism in similar ways, which suggests a possible interaction between these two strategies. To our knowledge, no studies have reported the associated effects of liposuction and exercise in humans. Nonetheless, one could suggest that exercise training associated with liposuction could attenuate or even block the possible compensatory fat deposition in intact depots or regrowth of the fat mass and exert an additive or even a synergistic effect to liposuction on improving insulin sensitivity and the inflammatory balance, resulting in an improvement of cardiovascular risk factors. Consequently, one could suggest that liposuction and exercise appear to be safe and effective strategies for either the treatment of metabolic disorders or aesthetic purposes.

A influência da intensidade do exercício físico aeróbio no processo aterosclerótico

A aterosclerose é um processo inflamatório crônico e degenerativo que acomete os vasos, sendo caracterizada pelo acúmulo de lipídeos no espaço subendotelial da íntima, acúmulo de células inflamatórias e elementos fibrosos. A oxidação de LDL-c parece ser o principal evento para o início da aterosclerose. O exercício físico aeróbio melhora os sistemas de defesa orgânicos contra aterosclerose, diminuindo o estresse oxidativo e aumentando a síntese de enzimas antioxidantes; aumento da vasodilatação via óxido nítrico (NO) e óxido nítrico sintase endotelial (eNOS) e diminuição da inflamação sistêmica com produção de citocinas pró-inflamatórias e aumento de fatores anti-inflamatórios. Porém, de maneira aguda, o exercício aeróbio de alta intensidade aumenta o risco de desenvolvimento de eventos cardiovasculares e, de forma crônica, pode atuar negativa ou positivamente na prevenção do processo aterosclerótico.

Effects of exercise combined with caloric restriction on inflammatory cytokines

Chronic inflammation has been implicated in the pathogenesis of several chronic diseases, such as atherosclerosis and diabetes, as well as certain types of cancers. It has been suggested that circulating biomarkers for inflammation may be modified by exercise; however, few laboratory-based studies have been conducted in nonobese premenopausal women. The purpose of this investigation was to determine the impact of a 4-month exercise training and caloric-restriction intervention with the goal of weight loss on circulating biomarkers of inflammation in sedentary premenopausal women aged 25–40 years (weight, 57 ± 2 kg). Subjects were studied for 6 consecutive menstrual cycles: 1 Screening, 1 Baseline, then 4 interventions (Interventions 1–4). Supervised aerobic training, consisting primarily of treadmill running and elliptical machine exercise, was performed 4 times per week for 40–90 min at 79% ± 0.7% of maximal heart rate. Subjects also consumed 30% fewer calories vs. baseline (1863 ± 58 to 1428 ± 53 kcal·day–1 (1 kcal = 4.186 kJ), p < 0.0001). Circulating inflammatory biomarkers, including adiponectin, high-sensitivity (hs) C-reactive protein (CRP), tumour necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), interferon-gamma (IFN-γ), and leptin, as well as body composition, aerobic capacity, and energy balance, were measured before and after the intervention. Maximal aerobic capacity increased by 8.5 ± 1.7 mL·kg–1·min–1 (p < 0.001) and body mass declined by an average of 3.7 ± 0.5 kg (p < 0.001). Significant reductions in IL-6 (0.39 ± 0.04 to 0.30 ± 0.03 pg·mL–1, p = 0.025), IFN-γ (0.58 ± 0.83 to 0.42 ± 0.64 pg·mL–1, p = 0.030), and leptin (13.18 ± 1.28 to 6.28 ± 0.71 pg·mL–1, p < 0.001) were detected in response to the intervention. No significant changes in adiponectin, hs-CRP, or TNF-α were found. Weight loss in response to exercise training and caloric restriction is effective in reducing inflammatory markers, specifically IL-6 and leptin.

Relationship of basal heart rate variability to in vivo cytokine responses after endotoxin exposure

Autonomic inputs from the sympathetic and parasympathetic nervous systems, as measured by heart rate variability (HRV), have been reported to correlate to the severity injury and responses to infectious challenge among critically ill patients. In addition, parasympathetic/vagal activity has been shown experimentally to exert anti-inflammatory effects via attenuation of splanchnic tissue TNF-alpha production. We sought to define the influence of gender on HRV responses to in vivo endotoxin challenge in healthy humans and to determine if baseline HRV parameters correlated with endotoxin-mediated circulating cytokine responses. Young (<30 years of age), healthy subjects (n = 30) received endotoxin (2 ng/kg), and HRV and blood samples were obtained serially thereafter. Plasma cytokines were measured by enzyme-linked immunosorbent assay, and HRV parameters were determined by analysis of serial 5-min epochs of heart rate monitoring. In addition, calculation of multiscale entropy deriving from cardiac monitoring data was performed. The influence of factors such as gender, body mass index, and resting heart rate on HRV after endotoxin exposure was assessed. We found that gender, body mass index, or resting heart rate did not significantly alter the HRV response after endotoxin exposure. Using entropy analysis, we observed that females had significantly higher entropy values at 24 h after endotoxin exposure. Using a serially sampling protocol for cytokine determination, we found a significant correlation of several baseline HRV parameters (percentage of interval differences of successive interbeat intervals more than 50 ms, r = 0.42, P < 0.05; high-frequency variability, r = 0.4, P < 0.05; and low-frequency/high-frequency ratio, r = -0.43, P < 0.05) on TNF-alpha release after endotoxin exposure.

Inflammatory changes upon a single maximal exercise test in depressed patients and healthy controls

Patients with major depressive disorder (MDD) have repeatedly been described to exhibit both a humoral as well as a cellular pro-inflammatory state. Acute exercise, representing physical stress, can further aggravate such an immune dysbalance. In the light of recommended exercise programmes for depressed patients, we aimed to investigate the inflammatory response to exercise in patients with MDD. Blood cells counts and concentrations of the pro-inflammatory cytokines IL-1ss and IL-6 as well as the anti-inflammatory cytokine IL-10 were obtained before and after a single maximum exercise test in 15 patients suffering from MDD and 15 controls applying a stepwise exhaustion protocol. Patients showed increased white cell counts before and after exercise. While starting from different baseline levels, however, the relative increase in both humoral and cellular inflammatory parameters did not differ between groups. The results from this study suggest that physical training programmes for MDD patients do not bear a dramatically increased risk for acute pro-inflammatory exacerbations. Thus, continuous training programmes that have been shown to reduce the pro-inflammatory state in these patients can be recommended.

Lower-extremity functional electrical stimulation decreases platelet aggregation and blood coagulation in persons with chronic spinal cord injury: a pilot study

BACKGROUND

Individuals with spinal cord injury (SCI) develop premature cardiovascular disease. Regular exercise reduces the incidence and symptoms of cardiovascular disease in able-bodied individuals; these salutary effects of exercise have not been documented in persons with SCI.

OBJECTIVE

To evaluate the effects of functional electrical stimulation leg cycle ergometry (FES-LCE) exercise training on platelet aggregation and blood coagulation in persons with SCI.

PARTICIPANTS

Subjects (n=14) with stable chronic (>1 year) paraplegia (T1-T10) or tetraplegia (C4-C8).

METHODS

Blood samples were collected before and after the first and eighth sessions (2 sessions per week for 4 weeks) of FES exercise.

RESULTS

Platelet aggregation was inhibited by 20% after the first session and by 40% (P < 0.001) after the eighth session. Thrombin activity was unchanged after the first session (10.7 +/- 0.85 s to 10.43 +/- 0.56 s) and decreased after the eighth session (12.5 +/- 1.98 s to 11.1 +/- 1.7 s; P < 0.0003). Antithrombin III activity increased after the first (103.8% +/- 8.9% to 110% +/- 6.9%; P < 0.0008) and eighth sessions (107.8% +/- 12.1% to 120.4% +/- 13.1%; P < 0.0001). Cyclic adenosine monophosphate increased after the first (9.9% + 2.5% to 15.8% +/- 3%; P < 0.001) and eighth sessions (17.8% +/- 4.2% to 36.5% +/- 7.6%; P < 0.0001). After the eighth session, factors V and X increased significantly (88% +/- 27% to 103% +/- 23%, P < 0.0001; 100% +/- 40% to 105% +/- 7%, P < 0.01, respectively); factors VII and VIII and fibrinogen did not change significantly. A significant reduction in platelet activation/aggregation was demonstrated in response to FES-LCE. The decrease in thrombin level was caused by the simultaneous increase in antithrombin activity.

CONCLUSION

These findings provide new insight into the potential protective effects of FES-LCE against the risk of cardiovascular disease.

Type 2 diabetes mellitus is associated with impaired cytokine response and adhesion molecule expression in human endotoxemia

PURPOSE

Type 2 diabetes is associated with an increased risk of acquiring infectious diseases and developing sepsis. This may partly be due to immune dysfunction. We investigated the in vivo innate immune response of type 2 diabetic persons to an intravenous injection of E. coli lipopolysaccharide (LPS).

METHODS

After ethics approval, informed consent and a thorough physical examination, 19 type 2 diabetic patients and 23 healthy controls were included. LPS was given as an intravenous bolus injection of 0.3 ng/kg. Physiological variables, white blood cell count, and plasma concentrations of tumour necrosis factor (TNF), interleukin-6 (IL-6), interleukin-1 receptor antagonist (IL-1ra), and the adhesion molecules E-selectin, vascular adhesion molecule (VCAM)-1, and intracellular adhesion molecule (ICAM)-1 were measured hourly for 8 h.

RESULTS

LPS injection induced a systemic inflammatory response with increases in neutrophils, temperature, heart rate and plasma concentrations of cytokines and adhesion molecules in healthy and type 2 diabetic volunteers. Type 2 diabetes was associated with less pronounced LPS-induced increases in TNF, IL-1ra, VCAM-1 and ICAM-1. There was a trend towards an attenuated upregulation of E-selectin in diabetics, even though the plasma concentration tended to be generally higher compared to healthy controls.

CONCLUSIONS

Patients with type 2 diabetes exhibit an attenuated increase in plasma levels of TNF and IL-1ra, as well as an attenuated upregulation of VCAM-1 and ICAM-1 to LPS in vivo. This finding may provide a mechanistic explanation for the adverse outcome seen during infectious diseases in diabetic patients.

Effect of exercise training on chronic inflammation

Persistent, sub-clinical inflammation, as indicated by higher circulating levels of inflammatory mediators, is a prominent risk factor for several chronic diseases, as well as aging-related disability. As such, the inflammatory pathway is a potential therapeutic target for lifestyle interventions designed to reduce disease and disability. Physical exercise is well recognized as an important strategy for reducing the risk of chronic disease, and recent research has focused on its role in the improvement of the inflammatory profile. This review summarizes the evidence for and against the role of increasing physical activity in the reduction of chronic inflammation. Large population-based cohort studies consistently show an inverse association between markers of systemic inflammation and physical activity or fitness status, and data from several small-scale intervention studies support that exercise training diminishes inflammation. However, data from large, randomized, controlled trials designed to definitively test the effects of exercise training on inflammation are limited, and results are inconclusive. Future studies are needed to refine our understanding of the effects of exercise training on systemic low-grade inflammation, the magnitude of such an effect, and the amount of exercise necessary to elicit clinically meaningful changes in the deleterious association between inflammation and disease.

Effect of physical activity on glutamine metabolism

PURPOSE OF REVIEW

Glutamine is largely synthesized in skeletal muscles and provides fuel to rapidly dividing cells of the immune system and precursors to gluconeogenesis in the liver. Physical exercise is known to affect glutamine synthesis and to modulate glutamine uptake. Overtraining is frequently associated with reduced availability of glutamine and decreased immunocompetence. Inactivity affects glutamine metabolism, but this subject was poorly investigated.

RECENT FINDINGS

Strenuous physical exercise as well as exhaustive training programs lead to glutamine depletion due to lowered synthesis and enhanced uptake by liver and immune cells. Evidence suggests that postexercise glutamine depletion is associated with immunodepression. Counterwise, moderate training leads to improved glutamine availability due to a positive balance between muscle synthesis and peripheral clearance. Physical inactivity, as investigated by experimental bed rest in healthy volunteers, reduced glutamine synthesis and availability.

SUMMARY

After exercise, a reduced glutamine availability may be considered as a marker of overtraining. An increased glutamine availability may contribute to decreased inflammation and health benefits associated with optimal training. Thus, glutamine supplementation may enhance immunocompetence after strenuous exercise. The potential of glutamine supplementation during physical inactivity needs to be explored.

Reflex control of immunity

Inflammation can cause damage and even death. What controls this primitive and potentially lethal innate immune response to injury and infection? Molecular and neurophysiological studies during the past decade have revealed a pivotal answer: immunity is coordinated by neural circuits that operate reflexively. The afferent arc of the reflex consists of nerves that sense injury and infection. This activates efferent neural circuits, including the cholinergic anti-inflammatory pathway, that modulate immune responses and the progression of inflammatory diseases. It might be possible to develop therapeutics that target neural networks for the treatment of inflammatory disorders.

Exercise training and plasma C-reactive protein and interleukin-6 in elderly people

OBJECTIVES

To determine the effects of a long-term exercise intervention on two prominent biomarkers of inflammation (C-reactive protein (CRP) and interleukin-6 (IL-6)) in elderly men and women.

DESIGN

Single-blind, randomized, controlled trial: The Lifestyle Interventions and Independence for Elders (LIFE) Trial.

SETTING

The Cooper Institute, Dallas, Texas; Stanford University, Stanford, California; University of Pittsburgh, Pittsburgh, Pennsylvania; and Wake Forest University, Winston-Salem, North Carolina.

PARTICIPANTS

Four hundred twenty-four elderly (aged 70-89), nondisabled, community-dwelling men and women at risk for physical disability.

INTERVENTION

A 12-month moderate-intensity physical activity (PA) intervention and a successful aging (SA) health education intervention.

MEASUREMENTS

CRP and IL-6.

RESULTS

After adjustment for baseline IL-6, sex, clinic site, diabetes mellitus, treatment group, visit, and group-by-visit interaction, the PA intervention resulted in a lower (P=.02) IL-6 concentration than the SA intervention. Adjusted mean IL-6 at month 12 was 8.5% (0.21 pg/mL) higher in the SA than the PA group. There were no significant differences in CRP between the groups at 12 months (P=.09). Marginally significant interaction effects of the PA intervention according to baseline functional status (P=.05) and IL-6 (above vs below the median; P=.06) were observed. There was a greater effect of the PA intervention on participants with lower functional status and those with a higher baseline IL-6.

CONCLUSION

Greater PA results in lower systemic concentrations of IL-6 in elderly individuals, and this benefit is most pronounced in individuals at the greatest risk for disability and subsequent loss of independence.