Different forms of physical activity—endurance, resistance or dynamic power—stimulate cytokine release from various tissues to the bloodstream. Receptors for exercise-induced cytokines are present in muscle tissue, adipose tissue, liver, brain, bones, cardiovascular system, immune system, pancreas, and skin. They have autocrine, paracrine and endocrine activities. Many of them regulate the myocyte growth and differentiation necessary for muscle hypertrophy and myogenesis. They also modify energy homeostasis, lipid, carbohydrate, and protein metabolism, regulate inflammation and exchange information (crosstalk) between remote organs. So far, interleukin 6 and irisin have been the best studied exercise-induced cytokines. However, many more can be grouped into myokines, hepatokines and adipomyokines. This review focuses on the less known exercise-induced cytokines such as myostatin, follistatin, decorin, brain-derived neurotrophic factor, fibroblast growth factor 21 and interleukin 15, and their relation to various forms of exercise, i.e., acute vs. chronic, regular training in healthy people.

Nowadays obesity becomes a significant global problem. Hence, recently more and more attention has been paid to substances present in the body that have a significant impact on metabolic processes and thermogenesis, in the context of their potential use in the prevention and treatment of obesity. It is well known that the relationship between thyroid hormones and obesity is multilayered, however recently, more and more information about the possible relation between thyroid hormones and muscle metabolism has been published. The aim of this review is to present the most updated information on the physiological impact of thyroid hormones on muscle tissue, as well as pathological changes related to the occurrence of various types of thyroid disorders, including hypothyroidism, hyperthyroidism and sick euthyroid syndrome. However, the data in humans still remains insufficient, and further studies are needed to fully explore the thyroid-muscle cross-talk.

In search of new treatment options for thyroid diseases, when conventional procedures are ineffective, contraindicated or associated with serious side effects, safety of thyroid arteries embolization in the treatment of particular thyroid diseases was evaluated. The study included eight subjects with retrosternal toxic goiter, six patients affected by Graves' disease, five cases of retrosternal non-toxic goiter, two subjects with post-amiodarone hyperthyroidism, and one patient with severe thyroid-related orbitopathy, who underwent selective embolization of thyroid arteries. The study assessed and compared calcium-phosphate balance, modulation of thyroid autoimmunity and the presence of different side effects in patients who underwent the procedure. In addition, the serum concentrations of thyroid hormones, anti-thyroid autoantibodies and thyroid volume have been measured. Five of all enrolled subjects (22.7 %) experienced transient, not clinically relevant hypocalcaemia with no need for calcium supplementation. There were no significant changes in serum calcium levels in patients after embolization of both inferior thyroid arteries. The transient side effects associated with the treatment were neck pain and a slight increase in body temperature. Noted high concentration of free thyroid hormones immediately after the procedure was not accompanied by worsening of symptoms or signs of thyrotoxicosis. In patients with Graves' disease, a significant decrease in thyrotropin receptor antibodies level was observed. Thyroid arterial embolization does not disturb permanently calcium-phosphate balance, modulates positively thyroid autoimmune processes and is associated with no serious post-procedure side effects. Hence, it may be considered as a safe and effective treatment modality for selected thyroid disorders.

Objective: It is well established, that thyroid hormones significantly affect skeletal muscles function, causing symptoms like myalgia and muscle weakness. Hypothyroid patients present increased levels of creatine kinase (CK), indicating muscle destruction. Lately, we proposed new serum markers of muscle disturbances in thyroid disorders - titin (TTN) and dystrophin (DMD). The aim of this study is to determine the association between thyroid status, muscle metabolism and serum levels of TTN and DMD in patients affected by hypo- and hyperthyroidism, before and after the treatment. Design and patients: In the study 56 subjects were enrolled. The studied group consisted of 16 patients with newly diagnosed overt hypothyroidism and 20 patients with hyperthyroidism. 20 healthy controls were also included in the study. Body composition, thyroid hormones and biochemical markers of muscle deterioration levels were evaluated before and after restoration of euthyroidism. Results: DMD and TTN levels were noticeably lower in the hypothyroid group and hyperthyroid group in comparison with controls, at the border of statistical significance. Along with the thyroid hormones and CK normalization, DMD levels increased in hypothyroid group, with no significant lowering of TTN levels. However, TTN concentrations and fT3/fT4 ratio became significantly lower than in controls. Hyperthyroid patients experienced no significant changes in TTN and DMD. Conclusions: Presented data indicates, TTN and DMD might be the potential new markers of musculoskeletal deterioration in thyroid disorders. In addition, the shift in TTN and DMD serum concentrations after the treatment of hypothyroidism accompanied by decreased fT3/fT4 ratio may suggest the influence of chosen therapeutic approach on muscle metabolism. Objective: It is well established, that thyroid hormones significantly affect skeletal muscles function, causing symptoms like myalgia and muscle weakness. Hypothyroid patients present increased levels of creatine kinase (CK), indicating muscle destruction. Lately, we proposed new serum markers of muscle disturbances in thyroid disorders - titin (TTN) and dystrophin (DMD). The aim of this study is to determine the association between thyroid status, muscle metabolism and serum levels of TTN and DMD in patients affected by hypo- and hyperthyroidism, before and after the treatment. Design and patients: In the study 56 subjects were enrolled. The studied group consisted of 16 patients with newly diagnosed overt hypothyroidism and 20 patients with hyperthyroidism. 20 healthy controls were also included in the study. Body composition, thyroid hormones and biochemical markers of muscle deterioration levels were evaluated before and after restoration of euthyroidism. Results: DMD and TTN levels were noticeably lower in the hypothyroid group and hyperthyroid group in comparison with controls, at the border of statistical significance. Along with the thyroid hormones and CK normalization, DMD levels increased in hypothyroid group, with no significant lowering of TTN levels. However, TTN concentrations and fT3/fT4 ratio became significantly lower than in controls. Hyperthyroid patients experienced no significant changes in TTN and DMD. Conclusions: Presented data indicates, TTN and DMD might be the potential new markers of musculoskeletal deterioration in thyroid disorders. In addition, the shift in TTN and DMD serum concentrations after the treatment of hypothyroidism accompanied by decreased fT3/fT4 ratio may suggest the influence of chosen therapeutic approach on muscle metabolism.