Amyotrophic Lateral Sclerosis and swim training affect copper metabolism in skeletal muscle in a mouse model of disease.

INTRODUCTION/AIMS: Swim training and regulation of copper metabolism result in clinical benefits in amyotrophic lateral sclerosis (ALS) mice. Therefore, the study aimed to determine whether swim training improves copper metabolism by modifying copper metabolism in the skeletal muscles of ALS mice. METHODS: SOD1G93A mice (n = 6 per group) were used as the ALS model, and wild-type B6SJL (WT) mice as controls (n = 6). Mice with ALS were analyzed before the onset of ALS (ALS BEFORE), at baseline ALS (first disease symptoms, trained and untrained, ALS ONSET), and at the end of ALS (last stage disease, trained and untrained, ALS TERMINAL). Copper concentrations and the level of copper metabolism proteins in the skeletal muscles of the lower leg were determined. RESULTS: ALS disease caused a reduction in the copper concentration in ALS TERMINAL untrained mice compared with the ALS BEFORE (10.43 ± 1.81 and 38.67 ± 11.50 µg/mg, respectively, p = .0213). The copper chaperon for SOD1 protein, which supplies copper to SOD1, and ATPase7a protein (copper exporter), increased at the terminal stage of disease by 57% (p = .0021) and 34% (p = .0372), while the CTR1 protein (copper importer) decreased by 45% (p = .002). Swim training moderately affected the copper concentration and the concentrations of proteins responsible for copper metabolism in skeletal muscles. DISCUSSION: The results show disturbances in skeletal muscle copper metabolism associated with ALS progression, which is moderately affected by swim training. From a clinical point of view, exercise in water for ALS patients should be an essential element of rehabilitation for maintaining quality of life.

Effect of Single High-Dose Vitamin D3 Supplementation on Post-Ultra Mountain Running Heart Damage and Iron Metabolism Changes: A Double-Blind Randomized Controlled Trial.

Exercise-induced inflammation can influence iron metabolism. Conversely, the effects of vitamin D3, which possesses anti-inflammatory properties, on ultramarathon-induced heart damage and changes in iron metabolism have not been investigated. Thirty-five healthy long-distance semi-amateur runners were divided into two groups: one group received 150,000 IU of vitamin D3 24 h prior to a race (n = 16), while the other group received a placebo (n = 19). Serum iron, hepcidin (HPC), ferritin (FER), erythroferrone (ERFE), erythropoietin (EPO), neopterin (NPT), and cardiac troponin T (cTnT) levels were assessed. A considerable effect of ultramarathon running on all examined biochemical markers was observed, with a significant rise in serum levels of ERFE, EPO, HPC, NPT, and cTnT detected immediately post-race, irrespective of the group factor. Vitamin D3 supplementation showed a notable interaction with the UM, specifically in EPO and cTnT, with no other additional changes in the other analysed markers. In addition to the correlation between baseline FER and post-run ERFE, HPC was modified by vitamin D. The ultramarathon significantly influenced the EPO/ERFE/HPC axis; however, a single substantial dose of vitamin D3 had an effect only on EPO, which was associated with the lower heart damage marker cTnT after the run.

Eight-day fasting modulates serum kynurenines in healthy men at rest and after exercise.

Introduction: Tryptophan's (Trp) metabolites are undervalued markers of human health. Their serum concentrations are modified by physical exercise and other factors, among which fasting has a well-documented role. Although this mechanism is hardly explored, thus, the study aimed to determine the effect of the 8-day fasting period and the impact of such a procedure on a single bout of an endurance exercise on the concentration of kynurenine pathway (KP) metabolites. Methods: 10 participants fasted for 8 days, and 10 as a control group participated in the study. The exercise was performed at baseline after an overnight fast and repeated post 8 days. Results: The 8 days of fasting increased the resting 3-hydroxy-L-kynurenine (3HK), picolinic acid (PA), kynurenic acid (KYNA), and xanthurenic acid (XA) serum concentration. Also elevated phenylalanine (Phe) and tyrosine (Tyr) levels were recorded, suggesting expanded proteolysis of muscle proteins. In turn, physical activity caused a decrease in the concentration of 3-hydroxyanthranilic acid (3HAA) and PA after fasting. The obtained results were not recorded in controls. Conclusion: The results of this study show that the health-promoting effects of fasting are associated with changes in the KYN pathway. The increase in the concentration of PA and XA metabolites following fasting is capable of penetrating the blood-brain barrier, and KYNA, which initiates several beneficial changes, supports this assumption.

The Impact of a 6-Week Nordic Walking Training Cycle and a 14-Hour Intermittent Fasting on Disease Activity Markers and Serum Levels of Wnt Pathway-Associated Proteins in Patients with Multiple Myeloma.

Background: Multiple myeloma (MM) accounts for about 10-15% of all diagnosed hematologic malignancies and about 1-2% of all cancer cases. Approximately 80-90% of MM patients develop bone disease and the changes rarely regress. It is only possible to stop or slow their progression. A major role in bone destruction in MM is attributed to the Wnt signaling pathway, and its action can be modified by various types of interventions including training and diet. Therefore, the aim of this project was to evaluate the effects of a Nordic Walking (NW) training cycle and intermittent fasting (IF) on the levels of selected bone turnover markers associated with the Wnt pathway in patients with MM. Materials and methods: Results from 35 patients divided into training (NW and IF NW) and non-training (IF and control) groups were included in the analysis. A 6-week training cycle involving 60 min workouts 3 times a week was conducted. Body mass and composition as well as the levels of vitamin D, calcium and phosphorus, beta2-microglobulin, and albumin were examined before and after the completion of the training cycle. Markers of bone turnover were also determined: sclerostin (SOST), Dickkopf-related protein 1 (DKK-1), osteoprotegrin (OPG), osteopontin (OPN), and Tartrate-resistant acid phosphatase 5b (TRACP 5b). Results: There was no negative effect of IF or combined training and fasting on the nutritional status of the patients (the level of albumins was unchanged). Both training groups showed an increase in serum concentrations of the active metabolite of vitamin D (IF NW and NW: p = 0.001 and p = 0.022, respectively). The change in the concentration of this vitamin negatively correlated with the concentration of TRACP 5b (r = -0.413, p = 0.014). Evaluating the concentrations of markers related to bone turnover, a reduction in the concentrations of SOST (time: p = 0.026, time vs. group: p = 0.033) and TRACP 5b (time: p < 0.001, time vs. group p < 0.001) was indicated. Conclusions: The obtained results allow one to indicate the training with the poles as a safe and beneficial form of physical activity that should be recommended to patients suffering from MM. However, the results obtained in the present study are not sufficient to show the beneficial effect of IF applied without trainings.

The Beneficial Effects of Nordic Walking Training Combined with Time-Restricted Eating 14/24 in Women with Abnormal Body Composition Depend on the Application Period.

The aim of the study was to assess the impact of two lengths of Nordic walking (NW) training interventions combined with time-restricted eating (TRE) on improving body-composition parameters, lipid profiles, and levels of selected adipokines in women with elevated body mass. Overweight and obese women (n = 55, age: 21-85) were recruited. Four groups were selected: 6 weeks (SG6, n = 13) and 12 weeks intervention (SG12, n = 13); and two control groups: CON6 (n = 13) and CON12 (n = 13). The training sessions took place three times a week (60 min each) and were conducted outdoors under the supervision of a professional coach. The training intensity was determined individually. The extended NW program combined with TRE induced a significant weight reduction in SG12 by 1.96 kg (p = 0.010) and fat tissue by 1.64 kg (p = 0.05). The proposed interventions did not affect LBM, TBW [kg], VFA, and lipid profile. The LDL/HDL ratio changed with a small size effect. The leptin concentration differed between groups (p = 0.006), but not over time. For resistin, the differentiating factor was time (p = 0.019), with lower results observed after the intervention. The change in leptin concentration was negatively correlated with its baseline concentration (p = 0.025). Extended to 12 weeks, this intervention allows for an improvement in body composition. Neither 6 nor 12 weeks of training and fasting affected the lipoprotein profile. It is, therefore, indicated to recommend prolonged training protocols and to inform patients that beneficial effects will be seen only after prolonged use of training and time-restricted eating.

Eight-Day Fast and a Single Bout of Exercise: The Effect on Serum Methylarginines and Amino Acids in Men.

Changes in serum concentration of methylarginines and amino acids after exercise are well documented, whereas the effects of exercise applied together with fasting are still debated and not thoroughly studied. Thus, we hypothesised that alterations in methylarginines such as ADMA, SDMA and L-NMMA might be responsible for decreased exercise performance after 8 days of fasting. Additionally, we propose that conditions in which the human body is exposed to prolonged fasting for more than a week elicit a distinctly different response to exercise than after overnight fasting. A group of 10 healthy men with previous fasting experience participated in the study. The exercise test was performed until exhaustion with a gradually increasing intensity before and after the 8-day fast. Blood samples were collected before and immediately after exercise. ADMA, SDMA, L-NMMA, dimethylamine and amino acids were analysed in serum samples by ID-LC-MS/MS. SDMA, L-NMMA and dimethylamine significantly decreased after 8 days of fasting, whereas ADMA did not change. BCAA, Phe, alanine and some other amino acids increased after fasting. Exercise-induced changes in amino acids were distinct after an 8-day fast compared to overnight fasting. A decrease in physical performance accompanied all of these alterations. In conclusion, our data indicate that neither methyl-arginine changes nor the Trp/BCAA ratio can explain exercise-induced fatigue after fasting. However, the observed decrease in hArg concentration suggests the limited synthesis of creatine, possibly contributing to reduced physical performance.

The Effect of Long-Lasting Swimming on Rats Skeletal Muscles Energy Metabolism after Nine Days of Dexamethasone Treatment.

This study investigates the effect of Dexamethasone (Dex) treatment on blood and skeletal muscle metabolites level and skeletal muscle activity of enzymes related to energy metabolism after long-duration swimming. To evaluate whether Dex treatment, swimming, and combining these factors act on analyzed data, rats were randomly divided into four groups: saline treatment non-exercise and exercise and Dex treatment non-exercised and exercised. Animals in both exercised groups underwent long-lasting swimming. The concentration of lipids metabolites, glucose, and lactate were measured in skeletal muscles and blood according to standard colorimetric and fluorimetric methods. Also, activities of enzymes related to aerobic and anaerobic metabolism were measured in skeletal muscles. The results indicated that Dex treatment induced body mass loss and increased lipid metabolites in the rats' blood but did not alter these changes in skeletal muscles. Interestingly, prolonged swimming applied after 9 days of Dex treatment significantly intensified changes induced by Dex; however, there was no difference in skeletal muscle enzymatic activities. This study shows for the first time the cumulative effect of exercise and Dex on selected elements of lipid metabolism, which seems to be essential for the patient's health due to the common use of glucocorticoids like Dex.

Short and long-term effects of high-intensity interval training applied alone or with whole-body cryostimulation on glucose homeostasis and myokine levels in overweight to obese subjects.

Background: COVID-19 pandemic has exacerbated the problem of physical inactivity and weight gain. Consequently, new strategies to counteract weight gain are being sought. Because of their accessibility, interval training and cold therapy are the most popular such strategies. We here aimed to examine the effect of 6 units of high-intensity interval training (HIIT), applied alone or in combination with 10 sessions of whole-body cryotherapy (WBC; 3 min at -110 ∘C per session) on incretins, myokines, and adipokines levels. Materials and methods: The study involved 65 subjects (body mass index of approximately 30 kg•m-2). The subjects were randomly divided into training group (TR; n = 27) and training supported by WBC group (TR-WBC; n = 38). Blood samples were collected before, immediately following, and 4 weeks after the intervention. Results: Fibroblast growth factor 21 (FGF21) levels significantly increased (p = 0.03) and adiponectin levels increased in the TR group (p = 0.05) compared with those recorded in TR-WBC group 24 h after the end of experimental protocol. Beneficial changes in the lipid profile (p = 0.07), a significant drop in visfatin levels (p < 0.05), and the improvement in ß-cell function (HOMA-B; p = 0.02) were also observed in the TR group in the same time point of study. While TR-WBC did not induce similar changes, it ameliorated blood glucose levels (p = 0.03). Changes induced by both interventions were only sustained for 4 weeks after treatment. Conclusion: Collectively, HIIT, alone and in combination with WBC, positively affects metabolic indicators, albeit, most likely, different mechanisms drive the beneficial effects of different treatments.

Fasting and Exercise Induce Changes in Serum Vitamin D Metabolites in Healthy Men.

BACKGROUND: Vitamin D plays pleiotropic roles in the body and hence, changes in its metabolism and distribution during starvation could play an important role in the adaptive response to famine. We aimed to identify the responses of some vitamin D metabolites to 8 d of fasting and exercise. METHODS: A repeated-measures design was implemented, in which 14 male volunteers fasted for 8 d and performed an exercise test before and after fasting. Serum samples were collected on day 1 after night fasting and after 8 d of complete food restriction, before and 1 h and 3 h after exercise. RESULTS: After 8 d of fasting, compared with baseline values, serum 24,25(OH)2D3 and 3-epi-25(OH)D3 levels significantly increased; those of 25(OH)D3 and 1,25(OH)2D3 were unaffected; and those of 25(OH)D2 decreased. Exercise on the first day of fasting induced an increase in serum 3-epi-25(OH)D3 levels, while exercise performed after 8 d of fasting induced an increase in 25(OH)D3, 24,25(OH)2D3, 25(OH)D2, and 3-epi-25(OH)D3 levels. CONCLUSION: Increases in 24,25(OH)2D3 and 3-epi-25(OH)D3 levels imply that fasting stimulates vitamin D metabolism. The effects of exercise on serum vitamin D metabolites, which are most pronounced after fasting and in subjects with serum 25(OH)D3 above 25 ng/mL, support the notion that fasting and exercise augment vitamin D metabolism.

Effect of 8-Day Fasting on Leukocytes Expression of Genes and Proteins Involved in Iron Metabolism in Healthy Men.

The popularity of fasting and restricted food intake is increasing. While the body's adaptability to dietary insufficiency is crucial for health, molecular mechanisms of adaptive changes are not well understood. Here, we compared the effects of fasting and exercise on the expression of leukocyte genes and proteins involved in the storage, export, and acquisition of iron, an essential element with physiological roles. Healthy men participated in the study (age, 30-70 years; body weight, 60-100 kg; body mass index, 20-29.9 kg/m2). The participants performed an exercise test with a gradually increasing intensity until the individual maximum exercise capacity was reached, before and after 8-d fast. Blood samples were collected before, immediately after, and 3 h after exercise. Gene expression was analyzed by reverse-transcription quantitative polymerase chain reaction and protein levels were analyzed by immunobloting. Eight days of total starvation diet affected the body composition and decreased exercise capacity. Further, fasting decreased the expression of genes associated with iron storage and export, and increased the expression of genes involved in iron acquisition. Conversely, only PCBP2 protein increased after fasting; however, an upward trend was apparent for all proteins. In conclusion, the body adapts to starvation by adjusting iron economy.

Single High-Dose Vitamin D Supplementation as an Approach for Reducing Ultramarathon-Induced Inflammation: A Double-Blind Randomized Controlled Trial.

Purpose: A growing number of studies indicate the importance of vitamin D supplementation for sports performance. However, the effects of a single high-dose vitamin D supplementation on ultramarathon-induced inflammation have not been investigated. We here analyzed the effect of a single high-dose vitamin D supplementation on the inflammatory marker levels in ultramarathon runners after an ultramarathon run (maximal run 240 km). Methods: In the study, 35 runners (amateurs) were assigned into two groups: single high-dose vitamin D supplementation group, administered vitamin D (150,000 IU) in vegetable oil 24 h before the start of the run (n = 16); and placebo group (n = 19). Blood was collected for analysis 24 h before, immediately after, and 24 h after the run. Results: Serum 25(OH)D levels were significantly increased after the ultramarathon in both groups. The increase was greater in the vitamin D group than in the control group. Based on post-hoc and other analyses, the increase in interleukin 6 and 10, and resistin levels immediately after the run was significantly higher in runners in the control group than that in those in the supplementation group. Leptin, oncostatin M, and metalloproteinase tissue inhibitor levels were significantly decreased in both groups after the run, regardless of the supplementation. Conclusions: Ultramarathon significantly increases the serum 25(OH)D levels. Attenuation of changes in interleukin levels upon vitamin D supplementation confirmed that vitamin D has anti-inflammatory effect on exercise-induced inflammation.

Homocysteine-induced decrease in HUVEC cells' resistance to oxidative stress is mediated by Akt-dependent changes in iron metabolism.

PURPOSE: Hyperhomocysteinemia is an independent risk factor for cardiovascular diseases and also promotes neuronal death in various neurodegenerative diseases. There is evidence that iron can mediate homocysteine (Hcy) toxicity. Thus, the aim of this study was to investigate the effect of Hcy on iron metabolism in HUVEC and SH-SY5Y cells. METHODS: HUVEC and SH-SY5Y cells were treated with 3 mM Hcy for a defined time. RESULTS: We demonstrate that Hcy induced the upregulation of ferritins type L and H in HUVEC cells in a time-dependent manner and had no effect on the ferritins in SH-SY5Y cells. The change in ferritin expression was preceded by a significant decrease in the cellular level of the active form of Akt kinase in HUVEC but not in SH-SY5Y cells. An increase in ferritin L and H protein levels was observed in the Akt1, Akt2, Akt3 siRNA transfected cells, while in the cells transfected with FOXO3a siRNA, a decrease in both ferritins levels was noticed. Moreover, in the HUVEC cells treated with Hcy for 6 days, the active form of kinase Akt returned to the control level and it was accompanied by a drop in ferritin L and H protein levels. Cytotoxicity of hydrogen peroxide significantly increased in HUVEC cells pre-treated with Hcy for 24 h. CONCLUSIONS: These data indicate that Hcy induces an increase in cellular ferritin level, and the process is mediated by alterations in Akt-FOXO3a signaling pathway.

Effect of Ischemic Preconditioning on Marathon-Induced Changes in Serum Exerkine Levels and Inflammation.

Participation in a long-distance run, e.g., marathon or ultramarathon, continues to increase. One side effect of long-distance running is excessive inflammation manifested by the rise in inflammatory cytokine levels. We here aimed to elucidate the effects of 10-day ischemic preconditioning (IPC) training on marathon-induced inflammation and to evaluate the role of serum-stored iron in this process. The study involved 19 recreational runners taking part in a marathon. IPC training was performed in the course of four cycles, by inflating and deflating a blood pressure cuff at 5-min intervals (IPC group, n = 10); the control group underwent sham training (n = 9). The levels of inflammatory and others markers (FSTL-1, IL-6, IL-15, leptin, resistin, TIMP-1, OSM, and LIF) were measured before and 24 h after training; and before, immediately after, and 24 h and 7 day after the marathon. The 10-day IPC training increased serum leptin levels. IL-6, IL-10, FLST-1, and resistin levels were increased, while TIMP-1 levels were decreased in all runners after the marathon. The changes were significantly blunted in runners from the IPC group compared with the control group. Baseline serum iron levels correlated with IL-6 and FSTL-1 levels; serum ferritin correlated with IL-6, FSTL-1, and resistin levels after the marathon. Conversely, serum TIMP-1 levels inversely correlated with serum iron levels. Although not evident at baseline, IPC training significantly reduced marathon-induced inflammation. In addition, the reduced responsiveness and attenuation of running-induced inflammation were inversely related to baseline serum iron and ferritin levels.

Marathon Run-induced Changes in the Erythropoietin-Erythroferrone-Hepcidin Axis are Iron Dependent.

Alterations in iron metabolism after physical activity are manifested through the rise of blood hepcidin (Hpc) levels. However, in many athletes, no changes in Hpc levels are observed after exercise despite the presence of inflammation. The missing links could be erythropoietin (EPO) and erythroferrone (ERFE), which down-regulate Hpc biosynthesis. EPO, ERFE and Hpc biosynthesis is modified by serum iron through transferrin receptor 2. Consequently, we investigated whether marathon-induced changes in EPO, ERFE and Hpc levels are blood iron-dependent. Twenty-nine healthy male marathon runners were analyzed. Serum iron, ferritin, transferrin, EPO, ERFE and Hpc levels were assessed before, immediately after, and 9 ± 2 days after the marathon. The runners whose serum Hpc decreased after the marathon (n = 15), showed a significant increase in ERFE levels. In athletes whose serum iron levels were below 105 µg/day (n = 15), serum EPO (p = 0.00) and ERFE levels (p = 0.00) increased with no changes in Hpc concentration. However, in athletes with low serum iron, no changes in EPO levels were observed when serum ferritin exceeded 70 ng/mL (n = 7). Conversely, an increase in ERFE levels was observed in marathoners with low serum iron, independently of serum ferritin (n = 7). This indicates modulation of blood iron may affect exercise-induced changes in the EPO/ERFE/Hpc axis. Further study is needed to fully understand the physiological meaning of the interdependence between iron and the EPO/ERFE/Hpc axis.

JNK/p66Shc/ITCH Signaling Pathway Mediates Angiotensin II-induced Ferritin Degradation and Labile Iron Pool Increase.

Angiotensin II (Ang II) induces deleterious changes in cellular iron metabolism and increases the generation of reactive oxygen species. This leads to an impairment of neuronal and vascular function. However, the mechanism underpinning Ang II-induced changes in iron metabolism is not known. We hypothesized that Ang II-induced ferritin degradation and an increase in the labile iron pool are mediated by the c-Jun N-terminal kinase (JNK)/p66Shc/ITCH signaling pathway. We show that Ang II treatment induced ferritin degradation in an endothelial cell lines derived from the bovine stem pulmonary artery (CPAE), human umbilical vein endothelial cells (HUVEC), and HT22 neuronal cells. Ferritin degradation was accompanied by an increase in the labile iron pool, as determined by changes in calcein fluorescence. The JNK inhibitor SP600125 abolished Ang II-induced ferritin degradation. Furthermore, the effect of Ang II on ferritin levels was completely abolished in cells transfected with vectors encoding catalytically inactive variants of JNK1 or JNK2. CPAE cells expressing inactive ITCHor p66Shc (substrates of JNK kinases) were completely resistant to Ang II-induced ferritin degradation. These observations suggest that Ang II-induced ferritin degradation and, hence, elevation of the levels of highly reactive iron, are mediated by the JNK/p66Shc/ITCH signaling pathway.

Ferritin Genes Overexpression in PBMC and a Rise in Exercise Performance as an Adaptive Response to Ischaemic Preconditioning in Young Men.

OBJECTIVES: The proposal of this study was to evaluate the effect of acute and ten-day ischaemic preconditioning (IPC) training procedure on the Wingate Anaerobic Test (WAnT), the ferritin H (FTH), ferritin L (FTL), and transferrin receptor 1 (TFRC) mRNA expression in peripheral blood mononuclear cells (PBMC), and anaerobic performance. METHOD: 34 healthy men volunteers (aged 20.7 ± 1.22 years) participated in the study. The effects of bilateral upper limb IPC and sham controlled condition were assessed in two experimental protocols: (a) the influence of acute (one time) IPC based on an experimental crossover study design and (b) the influence of ten-day IPC training treatment based on a random group assignment. At the beginning and at the end of each experiment upper body WAnT was performed and blood samples were collected to assess gene expression via quantitative PCR (qPCR). RESULTS: No significant effect of one-time ischaemic preconditioning procedure was observed on upper body WAnT performance. Ten-day IPC training significantly increased upper limbs relative mean power (from 5.29 ± 0.50 to 5.79 ± 0.70 (W/kg), p < 0.05). One-time IPC caused significant decrease in FTH, FTL, and TFRC mRNA levels while 10 days of IPC resulted in significant increase of FTH and FTL mRNA (from 2 ∧254.2 to 2 ∧1678.6 (p = 0.01) for FTH and 2 ∧81.5 to 2 ∧923 (p = 0.01) for FTL) and decrease in TFRC mRNA. CONCLUSIONS: Our findings suggest that ten-day IPC training intervention significantly affects upper limb relative peak power. The observed overexpression of FTH and FTL genes could be associated with adaptation response induced by prolonged IPC.

Iron Metabolism of the Skeletal Muscle and Neurodegeneration.

Recent studies clearly indicate that the endocrine function of the skeletal muscle is essential for a long and healthy life. Regular exercise, which has been shown to stimulate the release of myokines, lowers the risk of many diseases, including Alzheimer's and Parkinson's disease, emphasizing the role of skeletal muscle in proper functioning of other tissues. In addition, exercise increases insulin sensitivity, which may also impact iron metabolism. Even though the role of iron in neurodegeneration is well established, the exact mechanisms of iron toxicity are not known. Interestingly, exercise has been shown to modulate iron metabolism, mainly by reducing body iron stores. Insulin signaling and iron metabolism are interconnected, as high tissue iron stores are associated with insulin resistance, and conversely, impaired insulin signaling may lead to iron accumulation in an affected tissue. Excess iron accumulation in tissue triggers iron-dependent oxidative stress. Further, iron overload in the skeletal muscle not only negatively affects muscle contractility but also might impact its endocrine function, thus possibly affecting the clinical outcome of diseases, including neurodegenerative diseases. In this review, we discuss possible mechanisms of iron dependent oxidative stress in skeletal muscle, its impact on muscle mass and endocrine function, as well as on neurodegeneration processes.

hmSOD1 gene mutation-induced disturbance in iron metabolism is mediated by impairment of Akt signalling pathway.

BACKGROUND: Recently, skeletal muscle atrophy, impairment of iron metabolism, and insulin signalling have been reported in rats suffering from amyotrophic lateral sclerosis (ALS). However, the interrelationship between these changes has not been studied. We hypothesize that an impaired Akt-FOXO3a signalling pathway triggers changes in the iron metabolism in the muscles of transgenic animals. METHODS: In the present study, we used transgenic rats bearing the G93A hmSOD1 gene and their non-transgenic littermates. The study was performed on the muscles taken from animals at three different stages of the disease: asymptomatic (ALS I), the onset of the disease (ALS II), and the terminal stage of the disease (ALS III). In order to study the molecular mechanism of changes in iron metabolism, we used SH-SY5Y and C2C12 cell lines stably transfected with pcDNA3.1, SOD1 WT and SOD1 G93A, or FOXO3a TM-ER. RESULTS: A significant decrease in P-Akt level and changes in iron metabolism were observed even in the group of ALS I animals. This was accompanied by an increase in the active form of FOXO3a, up-regulation of atrogin-1, and catalase. However, significant muscle atrophy was observed in ALS II animals. An increase in ferritin L and H was accompanied by a rise in PCBP1 and APP protein levels. In SH-SY5Y cells stably expressing SOD1 or SOD1 G93A, we observed elevated levels of ferritin L and H and non-haem iron. Interestingly, insulin treatment significantly down-regulated ferritin L and H proteins in the cell. Conversely, cells transfected with small interfering RNA against Akt 1, 2, 3, respectively, showed a significant increase in the ferritin and FOXO3a levels. In order to assess the role of FOXO3a in the ferritin expression, we constructed a line of SH-SY5Y cells that expressed a fusion protein made of FOXO3a fused at the C-terminus with the ligand-binding domain of the oestrogen receptor (TM-ER) being activated by 4-hydroxytamoxifen. Treatment of the cells with 4-hydroxytamoxifen significantly up-regulated ferritin L and H proteins level. CONCLUSIONS: Our data suggest that impairment of insulin signalling and iron metabolism in the skeletal muscle precedes muscle atrophy and is mediated by changes in Akt/FOXO3a signalling pathways.

Cerulein-induced acute pancreatitis is associated with c-Jun NH(2)-terminal kinase 1-dependent ferritin degradation and iron-dependent free radicals formation.

OBJECTIVES: The main goal of this work was to get insight into the mechanism of cerulein-induced reactive oxygen species (ROS) formation and impact of c-Jun NH(2)-terminal kinase (JNK) on this process. METHODS: The study was performed on Wistar rats and on a cellular model of acute pancreatitis (AP) using AR42J cell line. RESULTS: First of all, we observed that during AP, the iron storage protein ferritin in the rat pancreas undergoes degradation accompanied by an increased formation of protein carbonyls. Pancreatic acinar AR42J cells stimulated by cerulein showed increased labile iron pool that was accompanied by a decrease in the cellular ferritin-L level and an increase in the ROS formation. The changes in the ferritin-L level were inversely correlated with the ROS formation. The cells expressing inactive JNK1 mutant were completely resistant to cerulein-induced ferritin degradation. CONCLUSIONS: Our data showed that cerulein-induced AP in rats and on cellular model is accompanied by JNK1-dependent ferritin degradation, increases labile iron pool and ROS formation.

Diallyl trisulfide is more cytotoxic to prostate cancer cells PC-3 than to noncancerous epithelial cell line PNT1A: a possible role of p66Shc signaling axis.

Diallyl trisulfide (DATS) is an organosulfur compound isolated from garlic, and has been shown to have anticancer activity both in vitro and in vivo. The aim of this study was to compare cytotoxic effects of DATS on prostate cancer cells PC-3 and noncancerous human prostate epithelial cells PNT1A. PC-3 prostate cancer and noncancerous human prostate epithelial cells PNT1A were used in the study. We observed that PNT1A cells had higher resistance to DATS-induced cell death than PC-3 cells. Investigating signaling pathways involved in the cell death we observed that p66Shc phosphorylation at serine 36 and extracellular signal-regulated kinase 1/2 activation induced by DATS, were significantly attenuated in PNT1A cells as compared to PC-3 cells. Moreover, DATS-induced Akt inactivation was also significantly reduced in PNT1A cells. In addition to that, DATS-induced reactive oxygen species generation was nearly completely abolished in PNT1A cells. Interestingly, DATS induced only slight decrease in the level of ferritin H, whereas ferritin L was elevated. These data suggest that cytotoxicity of DATS toward PNT1A cells is strongly reduced as opposed to PC-3 cancer cells, which corresponds to the lower activation of prodeath signaling pathway mediated by the adaptor protein p66Shc in the noncancerous PNT1A cells.