The cytokine response to strenuous exercise

Strenuous exercise is accompanied by an increase in circulating proinflammatory and inflammation responsive cytokines, having some similarities with the response to sepsis and trauma. The sequential release of tumour necrosis factor-alpha, interleukin (IL) 1 beta, IL-6, and IL-1 receptor antagonist (IL-1ra) in the blood is comparable to that observed in relation to bacterial diseases. Eccentric exercise is associated with an increase in serum IL-6 concentrations and is significantly correlated with the concentration of creatine kinase (CK) in the following days, whereas no changes are found after the concentric exercise; this demonstrates a close association between exercise-induced muscle damage and increased serum levels of IL-6. The time course of cytokine production, the close association with muscle damage, and the finding of mRNA-IL-6 in skeletal muscle biopsies after intense exercise all support the idea that during eccentric exercise myofibers are mechanically damaged and that this process stimulates the local production of inflammatory cytokines. It remains to be shown whether systemic endotoxemia during exercise is also a cause of elevated levels of cytokines in the plasma. The present review also discusses the possible roles of protein breakdown, delayed onset muscle soreness, and clinical implications of the acute-phase response following exercise.

Evidence that interleukin-6 is produced in human skeletal muscle during prolonged running

1. This study was performed to test the hypothesis that inflammatory cytokines are produced in skeletal muscle in response to prolonged intense exercise. Muscle biopsies and blood samples were collected from runners before, immediately after, and 2 h after a marathon race. 2. The concentration of interleukin (IL)-6 protein in plasma increased from 1.5 +/- 0.7 to 94.4 +/- 12.6 pg ml-1 immediately post-exercise and to 22.1 +/- 3.8 pg ml-1 2 h post-exercise. IL-1 receptor antagonist (IL-1ra) protein in plasma increased from 123 +/- 23 to 2795 +/- 551 pg ml-1, and increased further to 4119 +/- 527 pg ml-1 2 h post-exercise. 3. The comparative polymerase chain reaction technique was used to evaluate mRNA for IL-6, IL-1ra, IL-1beta and tumour necrosis factor (TNF)-alpha in skeletal muscle and blood mononuclear cells (BMNC) (n = 8). Before exercise, mRNA for IL-6 could not be detected either in muscle or in BMNC, and was only detectable in muscle biopsies (5 out of 8) after exercise. Increased amounts of mRNA for IL-1ra were found in two muscle biopsies and five BMNC samples, and increased amounts of IL-1beta mRNA were found in one muscle and four BMNC samples after exercise. TNF-alpha mRNA was not detected in any samples. 4. This study suggests that exercise-induced destruction of muscle fibres in skeletal muscles may trigger local production of IL-6, which stimulates the production of IL-1ra from circulating BMNC.

Recovery of the immune system after exercise

In the recovery phase after intense exercise is found suppressed blood concentration of lymphocytes, suppressed natural immunity of blood lymphocytes, decreased concentration of secretory IgA in mucosa, but increased blood concentration of neutrophils and increased levels in the blood of inflammatory cytokines. Thus, after intense long-term exercise, the immune system is characterized by concomitant inflammation and temporary suppression of the cellular immune system, the most pronounced findings being 2-4 h after the exercise. The underlying mechanisms are multifactorial and include neuroendocrinological and metabolic factors. High levels of cytokines, especially interleukin-6, are found in the recovery period after eccentric exercise, and it has been demonstrated that a close association exists between muscle damage and increased levels of interleukin-6.

[Bone mineralization in insulin-dependent diabetes mellitus]

One of insulin-dependent diabetes mellitus (IDDM) complications are bone mineral disorders called diabetic osteopathy. Because of many controversies of this subject we took a research of bone mineralisation in IDDM patients before 40 years old. The evaluation of BMD was performed with the use of X-ray dual energy absorptiometry--DEXA in the AP projection for lumbar part of vertebral column (BMD L2-L4), left femur neck (BMD-neck) and total skeleton (BMD-total). Bone tissue metabolism was evaluated with the aid of biochemical tests. The examined group consisted of 99 patients with IDDM (45 women and 54 men), without any other risk factors for changes in bone metabolism. The results were related to: sex, age in which IDDM was diagnosed, duration of IDDM, metabolic control of diabetes and to some IDDM complications. The control group consisted of 113 healthy subjects matched for age, sex, weight, height and calcium diet. We observed that BMD in IDDM patients before 40 years old was significantly lower than in healthy subject. One of some diabetic osteopathy pathomechanism seems to be an advantage of bone resorption over bone formation. Bone demineralisation which was observed to be most pronounced in femur neck, was not related to age, differed in accordance to sex and was higher of age when IDDM appeared was lower. BMD was also related to duration of IDDM and metabolic control of IDDM.

[Effect of low-dose recombinant humane erythropoietin therapy on the quality of life in patients with anemia in the course of end-stage renal failure treated with dialysis]

The aim of the study was to assess the efficacy of low-dose subcutaneous recombinant human erythropoietin (rHuEpo) therapy in hemodialysis patients with particular emphasis on their quality of life. Twenty five anemic (Ht25%) patients (14 males and 11 females, age 39-13 years) with end-stage renal disease were given rHuEpo (initial dose: 52.5 +/- 2.5 IU/kg/week; maintenance dose: 67.0-10.5 IU/kg/week) once or twice weekly for 12 months. Quality of life, assessed by self-administered questionnaire (1-3 scale), was measured every month. Additionally, sexual functions (-1 up to 3 scale, basal level 0), including libido and sexual satisfaction, and serum sex hormones (testosterone, LH, FSH, prolactin) were evaluated every 6 months. During first 4 months of the therapy there was a significant increase of Ht (21.1 +/- 0.5% vs 28.5 +/- 0.6%; p < 0.0001), which was maintained for the whole study period. From the 3rd month in majority of patients a marked (p < 0.01) improvement in their physical fitness, mood and cold tolerance was noted. Despite a substantial increase in sexual satisfaction (p < 0.01) and libido (p < 0.001), no significant changes in serum sex hormones profile, except transient rise in serum prolactin level, were observed. It is concluded that low-dose rHuEpo therapy for the renal anemia of hemodialysis patients is associated with a sustained significant improvement in their quality of life and sexual functions, despite no significant changes in sex hormones serum levels.

[Long-term treatment with large doses of alphacalicidol in secondary hyperparathyroidism of patients dialyzed for end stage renal failure]

The purpose of the study was to evaluate the effectiveness of the long-term oral pulse therapy with high doses of alphacalcidol (1 alpha (OH)D3) in severe uremic hyperparathyroidism. 43 hemodialysis patients with at least 5-fold 1-84 PTH serum elevation were given thrice a week oral (1 alpha (OH) D3) in doses up to 5 micrograms, according to serum calcium levels (monitored weekly). The drug was given in the evenings (Group A; 18 pts) or during hemodialysis sessions (Group B; 25 pts). The dialysate calcium was reduce to 1.40-1.45 mmol/l and CaCO3 was used as a main phosphate binder in doses up to 6 g/day; 13 pts received additionally small doses of Al (OH)3 (up to 3 g/day). After one month the PTH levels decreased by 67 +/- 7.7% (p < 0.001), while serum total calcium increased by 0.27 < or = 0.05 mmol/l. The parathyroid activity suppression progressed to 81 +/- 6.9% serum PTH reduction after 4 months and 74 +/- 6.1% fall after 8 months. Only 3 pts occurred to be non-responders; in 19 pts PTH levels normalized. A decrease of serum hydroxyproline and alkaline phosphatase with its bone isoenzyme activity was also observed with a direct correlation between those changes and parathyroid suppression. (1 alpha (OH) D3) dose at first month of therapy was 3.4 +/- 0.15 micrograms, but it was successively reduced because of hypercalcemia to a final dose of 2.2 +/- 0.22 micrograms. The frequency of hyperkalcemia was 7.6%; no difference between Group A and group B was noted. We conclude that oral (1 alpha (OH)D3) pulse therapy is very effective in the long-term parathyroid activity suppression in hemodialysis patients with severe hyperparathyroidism. To avoid dangerous hypercalcemia and relative hypoparathyroidism serum PTH and calcium levels should be carefully monitored.

[Combined therapy with calcitonin and high doses of active vitamin D3 metabolites in uremic hyperparathyroidism]

Active vitamin D3 pulse therapy effectively suppresses parathormone (PTH) synthesis in uremic hyperparathyroidism but high serum levels of calcitriol achieved can induce direct osteoclastic resorption and block bone formation. Therefore we found it interesting to examine whether an addition of the osteoclast inhibitor, calcitonin (CT), could reduce those unwanted effects. 75 hemodialysis patients with at least 5-fold 1-84 PTH serum level elevation were divided into 4 treatment groups: I (n = 19)-CT and 1 alpha-OH-D3; II (n = 20)-CT; III (n = 19)-1 alpha-OH-D3 (n = 10) or 1.25 (OH)2D3 (n = 9) alone; IV (n = 17)-none of these drugs. CT (200 IU) and 1 alpha-OH-D3/1.25(OH)2D3 (up to 5 micrograms) were given 3 times a week. Dialysate Ca was 1.40-1.45 (Group I, III) or 1.95-2.00 mmol/l (Group II, IV). Within 8 months serum 1-84 PTH fell by 75% (p < 0.001) in Group I and by 77% (p < 0.001) in Group II, serum Ca increased by 0.22 +/- 0.05 mmol/l in Group I (p < 0.005) and by 0.25 +/- 0.05 mmol/l in Group III (p < 0.005), alkaline phosphatase activity decreased by 35% in Group I (p < 0.01) and 31% in Group III (p < 0.005) whereas in Groups II and IV no significant changes were noted. In Group III no differences between patients taking 1 alpha-OH-D3 or 1.25 (OH)2D3 were observed. The significant reduction of serum hydroxyproline (37%; p < 0.001) was seen only in Group 1. The increase in bone mineral density (BMD) measured by dual-energy X-ray absorptiometry was greater in Group I than in Group III (p < 0.05). In Group II the effect was mostly insignificant, whereas in Group IV a substantial decrease (p < 0.001) in BMD was observed. These data suggest that combined therapy with CT and oral 1 alpha-OH-D3 pulses is more effective than pulses alone in inhibiting bone resorption and in increasing BMD in hemodialysis patients with uremic hyperparathyroid bone disease.

[Bone mineral disorders in patients with multiple myeloma]

The aim of the study was to evaluate bone mineralization in the patients with multiple myeloma. The examinations were performed in 49 patients (25 men and 24 women). Seven patients were before chemotherapy and 42 patients were treated with chemotherapy. All of them received prednisone. The bone mineral density was measured by dual-energy X-ray absorptiometry with Lunar spine (L2-L4) in AP projection, femoral neck and total body were examined. There was a decrease of bone mineral density in 35 patients in at least one place (T-score more than 2 SD below normal of young healthy persons). There was no correlation between densitometric results and the duration of multiple myeloma, or chemotherapy. The decrease of bone mineral density (expressed es T-score) of lumbar spine (for the patients without spinal degenerative changes) was higher than that of femoral neck (p < 0.05). The decrease of bone mineral density (expressed as T-score) of lumbar spine and femoral neck was more pronounced than that of total body (p < 0.001). Bone densitometry, especially of lumbar spine and femoral neck and less of total body is indicated in the patients with multiple myeloma. The result of this examination may be considered as an independent parameter of disease intensity.

[Effect of calcitonin treatment on bone mineralization in patients with multiple myeloma]

The aim of the study was to evaluate the efficacy of half-year treatment of bone mineral disturbances with calcitonin in the patients with multiple myeloma. Thirty five patients (11 men and 24 women) were examined. They were treated among other with prednisone. Nineteen patients (15 patients with normal bone mineral density of lumbar spine and femoral neck and 4 with low bone mineral density who could not be treated with calcitonin) were treated only with chemotherapy. Other 16 patients with low bone mineral density have received also calcitonin (100 units subcutaneous daily) with vitamin D3 and calcium carbonate. Bone mineral density was evaluated with dual energy X-ray absorptiometry in lumbar spine and femoral neck. After treatment with calcitonin there was more pronounced influence on bone mineral density in lumbar spine and femoral neck than after treatment with chemotherapy only but the difference was not statistically significant. Because the bone mineral disturbances in the patients with multiple myeloma is the big problem there is a need for further and longer evaluation of the treatment of these disturbances.

Nuragic bone collagen retains its molecular structure

The molecular structure of bone collagen was found to be preserved in Nuragic bone samples several centuries after burial. Enhanced birefringence of bone and dentin collagen fibres observed in polarized light after Sirus red staining was used to demonstrate this fact.