Current evidence on mesenchymal stem cells for hip osteoarthritis: a narrative review

There are limited data on the use of mesenchymal stem cell injections for hip osteoarthritis. The goal of this study was to evaluate the literature by analyzing outcomes and comparing methodologies. Online search of PubMed, SportsDiscus and Case Reports Keywords was completed using the keywords 'stem cells' and 'hip' and 'osteoarthritis'. Six studies met the inclusion and exclusion criteria. Five out the six studies had statistically significant improvement in patient reported outcomes after mesenchymal stem cell injections. Only two studies provided information on radiological changes and findings were positive. None of the studies reported major complications. Small series of non-randomized controlled trials completed to date in the use of mesenchymal stem cells for the treatment of hip osteoarthritis reported the procedures to be safe and provide a positive clinical response. Randomized controlled trials must be performed to further confirm mesenchymal stem cells as a treatment option for hip osteoarthritis.

Resistance Exercise Selectively Mobilizes Monocyte Subsets: Role of Polyphenols

PURPOSE

To examine the impact of polyphenol supplementation on the recruitment, mobilization, and activation of monocyte subsets after resistance exercise.

METHODS

Thirty-eight recreationally active males (22.1 ± 3.1 yr; 173.9 ± 7.9 cm; 77.8 ± 14.5 kg) were assigned to 28 d of polyphenol blend (PPB) supplementation, placebo (PL), or control (CON). Blood samples were obtained before (PRE) postresistance exercise, immediately (IP) postresistance exercise, 1 h (1H) postresistance exercise, 5 h (5H) postresistance exercise, 24 h (24H) postresistance exercise, and 48 h (48H) postresistance exercise (PPB/PL) or rest (CON). Fine-needle biopsies were obtained from the vastus lateralis at PRE, 1H, 5H, and 48H. Circulating concentrations of macrophage chemoattractant protein-1 (MCP-1) and fractalkine, as well as intramuscular MCP-1 were analyzed via multiplex assay. Changes in the proportions and expression of CD11b on monocyte subsets were assessed via flow cytometry.

RESULTS

Circulating MCP-1 increased in PPB and PL at IP with further increases at 5H. Intramuscular MCP-1 was increased at 1H, 5H, and 48H in all groups. Classical monocyte proportions were reduced in PPB and PL at IP, and increased at 1H. Nonclassical monocytes were increased in PPB and PL at IP, whereas intermediate monocytes were increased at IP, and reduced at 1H. Intermediate monocytes were increased in PPB at 24H and 48H. CD11b expression was reduced on PPB compared with PL and CON at PRE on intermediate and nonclassical monocytes.

CONCLUSIONS

Resistance exercise may elicit selective mobilization of intermediate monocytes at 24H and 48H, which may be mediated by tissue damage. Additionally, polyphenol supplementation may suppress CD11b expression on monocyte subsets at rest.

Comparison of sustained-release and rapid-release β-alanine formulations on changes in skeletal muscle carnosine and histidine content and isometric performance following a muscle-damaging protocol

β-alanine supplementation increases muscle carnosine content and improves anaerobic exercise performance by enhancing intracellular buffering capacity. β-alanine ingestion in its traditional rapid-release formulation (RR) is associated with the symptoms of paresthesia. A sustained-release formulation (SR) of β-alanine has been shown to circumvent paresthesia and extend the period of supply to muscle for carnosine synthesis. The purpose of this investigation was to compare 28 days of SR and RR formulations of β-alanine (6 g day^-1) on changes in carnosine content of the vastus lateralis and muscle fatigue. Thirty-nine recreationally active men and women were assigned to one of the three groups: SR, RR, or placebo (PLA). Participants supplementing with SR and RR formulations increased muscle carnosine content by 50.1% (3.87 mmol kg^-1ww) and 37.9% (2.62 mmol kg^-1ww), respectively. The change in muscle carnosine content in participants consuming SR was significantly different (p = 0.010) from those consuming PLA, but no significant difference was noted between RR and PLA (p = 0.077). Although participants ingesting SR experienced a 16.4% greater increase in muscle carnosine than RR, fatigue during maximal voluntary isometric contractions was significantly attenuated in both SR and RR compared to PLA (p = 0.002 and 0.024, respectively). Symptoms of paresthesia were significantly more frequent in RR compared to SR, the latter of which did not differ from PLA. Results of this study demonstrated that only participants consuming the SR formulation experienced a significant increase in muscle carnosine. Differences in the muscle carnosine response between these formulations may have practical significance for athletic populations in which small changes may have important implications on performance.

The effect of polyphenols on cytokine and granulocyte response to resistance exercise

This study examined the effect of resistance exercise on the production, recruitment, percentage, and adhesion characteristics of granulocytes with and without polyphenol (PPB) supplementation. Thirty‐eight untrained men were randomized into three groups: PPB (n = 13, 21.8 ± 2.5 years, 171.2 ± 5.5 cm, 71.2 ± 8.2 kg), placebo (PL; n = 15, 21.6 ± 2.5 years, 176.5 ± 4.9 cm, 84.0 ± 15.7 kg), or control (CON; n = 10, 23.3 ± 4.3 years, 173.7 ± 12.6 cm, 77.3 ± 16.3 kg). Blood samples were obtained pre (PRE), immediately (IP), 1 h (1H), 5 h (5H), 24 h (24H), 48 h (48H), and 96 h (96H) postresistance exercise (PPB/PL) or rest (CON). Fine‐needle biopsies were obtained from the vastus lateralis at PRE, 1H, 5H, and 48H. Plasma concentrations and intramuscular content of interleukin‐8 (IL‐8), granulocyte (G‐CSF), and granulocyte–macrophage colony stimulating factor (GM‐CSF) were analyzed via multiplex assays. Changes in relative number of circulating granulocytes and adhesion receptor (CD11b) were assessed using flow cytometry. Intramuscular IL‐8 was significantly elevated at 1H, 5H, and 48H (P < 0.001). Area under the curve analysis indicated a greater intramuscular IL‐8 content in PL than PPB (P = 0.011). Across groups, circulating G‐CSF was elevated from PRE at IP (P < 0.001), 1H (P = 0.011), and 5H (P = 0.025), while GM‐CSF was elevated at IP (P < 0.001) and 1H (P = 0.007). Relative number of granulocytes was elevated at 1H (P < 0.001), 5H (P < 0.001), and 24H (P = 0.005, P = 0.006) in PPB and PL, respectively. Across groups, granulocyte CD11b expression was upregulated from PRE to IP (P < 0.001) and 1H (P = 0.015). Results indicated an increase in circulating CD11b on granulocytes, and IL‐8 within the muscle following intense resistance exercise. Polyphenol supplementation may attenuate the IL‐8 response, however, did not affect granulocyte percentage and adhesion molecule expression in peripheral blood following resistance exercise.

Monocyte Recruitment after High-Intensity and High-Volume Resistance Exercise

The innate immune response is generally considered to have an important role in tissue remodeling after resistance exercise.

PURPOSE

The purpose of this study was to compare changes in markers of monocyte recruitment after an acute bout of high-intensity (HVY) versus high-volume (VOL) lower-body resistance exercise.

METHODS

Ten resistance-trained men (24.7 ± 3.4 yr, 90.1 ± 11.3 kg, 176.0 ± 4.9 cm) performed each protocol in a randomized, counterbalanced order. Blood samples were collected at baseline, immediately (IP), 30 min (30P), 1 h (1H), 2 h (2H), and 5 h (5H) postexercise. Plasma concentrations of monocyte chemoattractant protein 1 (MCP-1), tumor necrosis factor alpha (TNF-α), myoglobin, and cortisol were measured via assay. Tumor necrosis factor receptor 1 (TNFr1), macrophage-1 antigen (cluster of differentiation 11b [CD11b]), and C-C chemokine receptor 2 (CCR2) expression levels were measured using flow cytometry. TNFr1 and CD11b were assessed on CD14CD16 monocytes, whereas CCR2 was assessed on CD14 monocytes.

RESULTS

Plasma myoglobin concentrations were significantly greater after HVY compared with VOL (P < 0.001). Changes in plasma TNF-α, MCP-1, and expression levels of CCR2 and CD11b were similar between HVY and VOL. When collapsed across groups, TNF-α was significantly increased at IP, 30P, 1H, and 2H (P values < 0.05), whereas MCP-1 was significantly elevated at all postexercise time points (P values < 0.05). CCR2 expression on CD14 monocytes was significantly lower at IP, 1H, 2H, and 5H (P values < 0.05). CD11b expression on CD14 CD16 was significantly greater at IP (P < 0.014) and 1H (P = 0.009). TNFr1 expression did not differ from baseline at any time point. Plasma cortisol concentrations did not seem to be related to receptor expression.

CONCLUSIONS

Results indicate that both HVY and VOL protocols stimulate a robust proinflammatory response. However, no differences were noted between resistance exercise training paradigms.

Post-resistance exercise ingestion of milk protein attenuates plasma TNFα and TNFr1 expression on monocyte subpopulations

Attenuating TNFα/TNFr1 signaling in monocytes has been proposed as a means of mitigating inflammation. The purpose of this study was to examine the effects of a milk protein supplement on TNFα and monocyte TNFr1 expression. Ten resistance-trained men (24.7 ± 3.4 years; 90.1 ± 11.3 kg; 176.0 ± 4.9 cm) ingested supplement (SUPP) or placebo (PL) immediately post-exercise in a randomized, cross-over design. Blood samples were obtained at baseline (BL), immediately (IP), 30-min (30P), 1-h (1H), 2-h (2H), and 5-h (5H) post-exercise to assess plasma concentrations of myoglobin; tumor necrosis factor-alpha (TNFα); and expression of tumor necrosis factor receptor 1 (TNFr1) on classical, intermediate, and non-classical monocytes. Magnitude-based inferences were used to provide inferences on the true effects of SUPP compared to PL. Plasma TNFα concentrations were "likely attenuated" (91.6% likelihood effect) from BL to 30P in the SUPP group compared with PL (d = 0.87; mean effect: 2.3 ± 2.4 pg mL^-1). TNFr1 expressions on classical (75.9% likelihood effect) and intermediate (93.0% likelihood effect) monocytes were "likely attenuated" from BL to 2H in the SUPP group compared with PL (d = 0.67; mean effect: 510 ± 670 RFU, and d = 1.05; mean effect: 2500 ± 2300 RFU, respectively). TNFr1 expression on non-classical monocytes was "likely attenuated" (77.6% likelihood effect) from BL to 1H in the SUPP group compared with PL (d = 0.69; mean effect: 330 ± 430 RFU). Ingestion of a milk protein supplement immediately post-exercise appears to attenuate both plasma TNFα concentrations and TNFr1 expression on monocyte subpopulations in resistance-trained men.

Comparison of the recovery response from high-intensity and high-volume resistance exercise in trained men

PURPOSE

The purpose of this study was to compare the physiological responses of a high-volume (HV; 8 sets of 10 repetitions) versus high-intensity (HI; 8 sets of 3 repetitions) exercise protocol in resistance-trained men.

METHODS

Twelve men (24.5 ± 4.2 years; 82.3 ± 8.4 kg; 175.2 ± 5.5 cm) with 6.3 ± 3.4 years of resistance training experience performed each protocol in a counterbalanced, randomized order. Performance [counter movement jump peak power (CMJP), isokinetic (ISOK) and isometric leg extension (MVIC), isometric mid-thigh pull (IMTP), and isometric squat (ISQ)] and muscle morphological [cross-sectional area (CSA) of vastus lateralis] assessments were performed at baseline (BL), 30-min (P-30 min), 24-h (P-24 h), 48-h (P-48 h), and 72-h (P-72 h) post-exercise for each testing session. In addition, endocrine (testosterone and cortisol), inflammatory [interleukin-6 (IL-6) and C-reactive protein (CRP)], and markers of muscle damage [creatine kinase (CK), lactate dehydrogenase (LDH), and myoglobin (Mb)] were assessed at the same time points.

RESULTS

Significantly greater reductions in CMJP (p < 0.001), and peak torque during both ISOK (p = 0.003) and MVIC (p = 0.008) at P-30 min were detected in HV compared to HI protocol. MVIC was still impaired at P-72 h following the HV protocol, while no differences were noted following HI. Markers of muscle damage (LDH, CK, and Mb) were significantly elevated following both HV and HI (p < 0.05), while cortisol and IL-6 concentrations were significantly elevated at P-30 min following HV only (p < 0.001 and p < 0.05, respectively).

CONCLUSIONS

Results indicate that high-volume resistance exercise results in greater performance deficits, and a greater extent of muscle damage, than a bout of high-intensity resistance exercise.

Do different tendons exhibit the same response following chronic exposure to statins?

Over the past few years, a number of cases of tendon injuries associated with statin therapy have been reported. In this study, we assessed whether statins can affect the extracellular matrix (ECM) of the deep digital flexor tendon (DDFT) and patellar tendon (PT). Wistar rats were assigned to groups treated with atorvastatin (A20, A80), treated with simvastatin (S20, S80), and control. Zymography, Western blotting for collagen I, non-collagenous proteins (NCP), glycosaminoglycans (GAGs), and hydroxyproline quantifications were performed. DDFT findings: NCP were increased in A20 and A80; higher concentration of hydroxyproline was found in S80; levels of GAGs was increased in all statin-treated groups; collagen I was increased in S80 and pro-MMP-2 activity was reduced in A80, S20, and S80. PT findings: NCP were reduced in A20, A80, and S80; GAGs was reduced in A80 and S20; collagen I was increased in A20 and pro-MMP-2 activity was reduced in the S20. Both the statins provoked marked changes in both tendons. All these changes may make the tendons more prone to microdamage and ruptures. Therefore, a better understanding of the behavior of the tendon ECM components under statin therapy may provide important insights into the mechanisms behind statin-induced tendon injuries.

The effect of polyphenols on cytokine and granulocyte response to resistance exercise

This study examined the effect of resistance exercise on the production, recruitment, percentage, and adhesion characteristics of granulocytes with and without polyphenol (PPB) supplementation. Thirty-eight untrained men were randomized into three groups: PPB (n = 13, 21.8 ± 2.5 years, 171.2 ± 5.5 cm, 71.2 ± 8.2 kg), placebo (PL; n = 15, 21.6 ± 2.5 years, 176.5 ± 4.9 cm, 84.0 ± 15.7 kg), or control (CON; n = 10, 23.3 ± 4.3 years, 173.7 ± 12.6 cm, 77.3 ± 16.3 kg). Blood samples were obtained pre (PRE), immediately (IP), 1 h (1H), 5 h (5H), 24 h (24H), 48 h (48H), and 96 h (96H) postresistance exercise (PPB/PL) or rest (CON). Fine-needle biopsies were obtained from the vastus lateralis at PRE, 1H, 5H, and 48H. Plasma concentrations and intramuscular content of interleukin-8 (IL-8), granulocyte (G-CSF), and granulocyte-macrophage colony stimulating factor (GM-CSF) were analyzed via multiplex assays. Changes in relative number of circulating granulocytes and adhesion receptor (CD11b) were assessed using flow cytometry. Intramuscular IL-8 was significantly elevated at 1H, 5H, and 48H (P < 0.001). Area under the curve analysis indicated a greater intramuscular IL-8 content in PL than PPB (P = 0.011). Across groups, circulating G-CSF was elevated from PRE at IP (P < 0.001), 1H (P = 0.011), and 5H (P = 0.025), while GM-CSF was elevated at IP (P < 0.001) and 1H (P = 0.007). Relative number of granulocytes was elevated at 1H (P < 0.001), 5H (P < 0.001), and 24H (P = 0.005, P = 0.006) in PPB and PL, respectively. Across groups, granulocyte CD11b expression was upregulated from PRE to IP (P < 0.001) and 1H (P = 0.015). Results indicated an increase in circulating CD11b on granulocytes, and IL-8 within the muscle following intense resistance exercise. Polyphenol supplementation may attenuate the IL-8 response, however, did not affect granulocyte percentage and adhesion molecule expression in peripheral blood following resistance exercise.

A Microbiopsy Method for Immunohistological and Morphological Analysis: A Pilot Study

INTRODUCTION

The fine aspiration microbiopsy is a relatively new biopsy technique, which allows muscle physiologists to sample skeletal muscle less invasively. However, the small sample size obtained is often deemed insufficient for certain analyses. The aim of the current study was to develop procedures for muscle fiber morphology and immunohistological analysis from a microbiopsy technique.

METHODS

Microbiopsies of the vastus lateralis were taken with a 14-gauge microbiopsy needle from four healthy men on two separate occasions. The tissue was oriented in a cryomold, embedded in Tissue-Tek® then frozen in liquid nitrogen cooled isopentane. The muscle sections were stained with hematoxylin and eosin, laminin, MHCI, MHCIIa, and Pax7 for fiber number, mean fiber area, muscle fiber typing, and satellite cell observation.

RESULTS

The mean ± SD (range) microbiopsy sample weight was 18.3 ± 2.9 mg (14-22 mg). The mean fiber number within the microbiopsy specimens was 150.4 ± 120.6 (64-366). All viable fibers were measured in each sample, and the mean fiber area was 4385.1 ± 1265.8 μm2 (977.0-10,132.93 μm2). There was no significant time difference (P = 0.69) in mean fiber area.

DISCUSSION

Results suggest the potential use of a "minimally invasive" muscle biopsy technique for immunohistological and morphological analysis. This could provide clinicians and investigators additional data in future research. Further investigations are needed to determine the usefulness and potential limiting factors of this technique.

Resistance exercise increases intramuscular NF-κb signaling in untrained males

PURPOSE

The NF-κB signaling pathway regulates multiple cellular processes following exercise stress. This study aims to examine the effects of an acute lower-body resistance exercise protocol and subsequent recovery on intramuscular NF-κB signaling.

METHODS

Twenty-eight untrained males were assigned to either a control (CON; n = 11) or exercise group (EX; n = 17) and completed a lower-body resistance exercise protocol consisting of the back squat, leg press, and leg extension exercises. Skeletal muscle microbiopsies were obtained from the vastus lateralis pre-exercise (PRE), 1-hour (1H), 5-hours (5H), and 48-hours (48H) post-resistance exercise. Multiplex signaling assay kits (EMD Millipore, Billerica, MA, USA) were used to quantify the total protein (TNFR1, c-Myc) or phosphorylation status of proteins belonging to the NF-κB signaling pathway (IKKa/b, IkBα, NF-κB) using multiplex protein assay. Repeated measures ANOVA analysis was used to determine the effects of the exercise bout on intramuscular signaling at each time point. Additionally, change scores were analyzed by magnitude based inferences to determine a mechanistic interpretation.

RESULTS

Repeated measures ANOVA indicated a trend for a two-way interaction between the EX and CON Group (p = 0.064) for c-Myc post resistance exercise. Magnitude based inference analysis suggest a "Very Likely" increase in total c-Myc from PRE-5H and a "Likely" increase in IkBα phosphorylation from PRE-5H post-resistance exercise.

CONCLUSION

Results indicated that c-Myc transcription factor is elevated following acute intense resistance exercise in untrained males. Future studies should examine the role that post-resistance exercise NF-κβ signaling plays in c-Myc induction, ribosome biogenesis and skeletal muscle regeneration.

Leukocyte IGF-1 receptor expression during muscle recovery

INTRODUCTION

The insulin-like growth factor 1 (IGF-1) system plays a central role in anabolic cellular processes. Recently, a regulatory role of IGF-1 in the immune response for muscle repair has been suggested, but how it modulates the inflammatory process is largely unknown. We evaluated changes in leukocyte expression of IGF-1 receptors (IGF-1R) during recovery from resistance exercise to determine whether changes in the potential for IGF-1 interactions with leukocytes may mediate the role of IGF-1 in muscle repair.

METHODS

Twenty resistance-trained men (18-35 yr) performed resistance exercise followed by cold water immersion (CWI) or control treatment (CON) on three consecutive days. Blood was sampled at baseline (PRE), immediately (IP), 30 min (30P), 24 h (24H), and 48 h after (48H) exercise. Circulating IGF-1 was assayed, and IGF-1 receptor expression (CD221) on gated circulating leukocytes (monocytes, granulocytes, and lymphocytes) was measured by flow cytometry. Time and treatment effects were analyzed with ANCOVA.

RESULTS

Circulating IGF-1 significantly increased from PRE to IP as a result of resistance exercise, but no differences between CON and CWI were observed. Mean fluorescence intensity of CD221 on monocytes and granulocytes and percent of CD221+ granulocytes significantly increased at 30P (P < 0.000) and returned to preexercise levels by 24H. No treatment effects on monocytes or granulocytes were observed. On lymphocytes, mean fluorescence intensity of CD221+ significantly increased from PRE to 30P in CWI.

CONCLUSIONS

Changes in IGF-1 and its receptor on monocytes and granulocytes seem to be part of the mechanism that facilitates recovery from resistance exercise during earlier stages of muscle recovery. In addition, CWI seems to alter IGF-mediated responses on slower-acting lymphocytes, suggesting that its effects may be seen in later stages of muscle repair.

Protein supplementation does not alter intramuscular anabolic signaling or endocrine response after resistance exercise in trained men

The mammalian/mechanistic target of rapamycin complex 1 (mTORC1) signaling pathway appears to be the primary regulator of muscle protein synthesis. A variety of stimuli including resistance exercise, amino acids, and hormonal signals activate mTORC1 signaling. The purpose of this study was to investigate the effect of a protein supplement on mTORC1 signaling following a resistance exercise protocol designed to promote elevations in circulating hormone concentrations. We hypothesized that the protein supplement would augment the intramuscular anabolic signaling response. Ten resistance-trained men (age, 24.7 ± 3.4 years; weight, 90.1 ± 11.3 kg; height, 176.0 ± 4.9 cm) received either a placebo or a supplement containing 20 g protein, 6 g carbohydrates, and 1 g fat after high-volume, short-rest lower-body resistance exercise. Blood samples were obtained at baseline, immediately, 30 minutes, 1 hour, 2 hours, and 5 hours after exercise. Fine-needle muscle biopsies were completed at baseline, 1 hour, and 5 hours after exercise. Myoglobin, lactate dehydrogenase, and lactate concentrations were significantly elevated after resistance exercise (P < .0001); however, no differences were observed between trials. Resistance exercise also elicited a significant insulin, growth hormone, and cortisol response (P < .01); however, no differences were observed between trials for insulin-like growth factor-1, insulin, testosterone, growth hormone, or cortisol. Intramuscular anabolic signaling analysis revealed significant elevations in RPS6 phosphorylation after resistance exercise (P = .001); however, no differences were observed between trials for signaling proteins including Akt, mTOR, p70S6k, and RPS6. The endocrine response and phosphorylation status of signaling proteins within the mTORC1 pathway did not appear to be altered by ingestion of supplement after resistance exercise in resistance-trained men.

Intramuscular anabolic signaling and endocrine response following high volume and high intensity resistance exercise protocols in trained men

Resistance exercise paradigms are often divided into high volume (HV) or high intensity (HI) protocols, however, it is unknown whether these protocols differentially stimulate mTORC1 signaling. The purpose of this study was to examine mTORC1 signaling in conjunction with circulating hormone concentrations following a typical HV and HI lower-body resistance exercise protocol. Ten resistance-trained men (24.7 ± 3.4 years; 90.1 ± 11.3 kg; 176.0 ± 4.9 cm) performed each resistance exercise protocol in a random, counterbalanced order. Blood samples were obtained at baseline (BL), immediately (IP), 30 min (30P), 1 h (1H), 2 h (2H), and 5 h (5H) postexercise. Fine needle muscle biopsies were completed at BL, 1H, and 5H. Electromyography of the vastus lateralis was also recorded during each protocol. HV and HI produced a similar magnitude of muscle activation across sets. Myoglobin and lactate dehydrogenase concentrations were significantly greater following HI compared to HV (P = 0.01–0.02), whereas the lactate response was significantly higher following HV compared to HI (P = 0.003). The growth hormone, cortisol, and insulin responses were significantly greater following HV compared to HI (P = 0.0001–0.04). No significant differences between protocols were observed for the IGF-1 or testosterone response. Intramuscular anabolic signaling analysis revealed a significantly greater (P = 0.03) phosphorylation of IGF-1 receptor at 1H following HV compared to HI. Phosphorylation status of all other signaling proteins including mTOR, p70S6k, and RPS6 were not significantly different between trials. Despite significant differences in markers of muscle damage and the endocrine response following HV and HI, both protocols appeared to elicit similar mTORC1 activation in resistance-trained men.

Effects of time-release caffeine containing supplement on metabolic rate, glycerol concentration and performance

This study compared caffeine pharmacokinetics, glycerol concentrations, metabolic rate, and performance measures following ingestion of a time-release caffeine containing supplement (TR-CAF) versus a regular caffeine capsule (CAF) and a placebo (PL). Following a double-blind, placebo-controlled, randomized, cross-over design, ten males (25.9 ± 3.2 y) who regularly consume caffeine ingested capsules containing either TR-CAF, CAF, or PL. Blood draws and performance measures occurred at every hour over an 8-hour period. Plasma caffeine concentrations were significantly greater (p < 0.05) in CAF compared to TR-CAF during hours 2-5 and significantly greater (p = 0.042) in TR-CAF compared to CAF at hour 8. There were no significant differences between trials in glycerol concentrations (p = 0.86) or metabolic measures (p = 0.17-0.91). Physical reaction time was significantly improved for CAF at hour 5 (p=0.01) compared to PL. Average upper body reaction time was significantly improved for CAF and TR-CAF during hours 1-4 (p = 0.04 and p = 0.01, respectively) and over the 8-hour period (p = 0.04 and p = 0.001, respectively) compared to PL. Average upper body reaction time was also significantly improved for TR-CAF compared to PL during hours 5-8 (p = 0.004). TR-CAF and CAF showed distinct pharmacokinetics yielding modest effects on reaction time, yet did not alter glycerol concentration, metabolic measures, or other performance measures. Key pointsTime-release caffeine and regular caffeine showed distinct pharmacokinetics over an 8-hour period following ingestion.Time-release caffeine and regular caffeine yielded modest effects on reaction time over an 8-hour period following ingestion.Time-release caffeine and regular caffeine did not alter glycerol concentration, metabolic measures, or other performance measures over an 8-hour period following ingestion.

Association between myosin heavy chain protein isoforms and intramuscular anabolic signaling following resistance exercise in trained men

Resistance exercise stimulates an increase in muscle protein synthesis regulated by intracellular anabolic signaling molecules in a mammalian/mechanistic target of rapamycin (mTOR)‐dependent pathway. The purpose of this study was to investigate acute anabolic signaling responses in experienced, resistance‐trained men, and to examine the association between myosin heavy chain (MHC) isoform composition and the magnitude of anabolic signaling. Eight resistance‐trained men (24.9 ± 4.3 years; 91.2 ± 12.4 kg; 176.7 ± 8.0 cm; 13.3 ± 3.9 body fat %) performed a whole body, high‐volume resistance exercise protocol (REX) and a control protocol (CTL) in a balanced, randomized order. Participants were provided a standardized breakfast, recovery drink, and meal during each protocol. Fine needle muscle biopsies were completed at baseline (BL), 2 h (2H) and 6 h post‐exercise (6H). BL biopsies were analyzed for MHC isoform composition. Phosphorylation of proteins specific to the Akt/mTOR signaling pathway and MHC mRNA expression was quantified. Phosphorylation of p70S6k was significantly greater in REX compared to CTL at 2H (P = 0.04). MHC mRNA expression and other targets in the Akt/mTOR pathway were not significantly influenced by REX. The percentage of type IIX isoform was inversely correlated (P < 0.05) with type I and type IIA MHC mRNA expression (r = −0.69 to −0.93). Maximal strength was also observed to be inversely correlated (P < 0.05) with Type I and Type IIA MHC mRNA expression (r = −0.75 to −0.77) and p70S6k phosphorylation (r = −0.75). Results indicate that activation of p70S6k occurs within 2‐h following REX in experienced, resistance‐trained men. Further, results also suggest that highly trained, stronger individuals have an attenuated acute anabolic response.

Resistance exercise stimulates an increase in muscle protein synthesis regulated by intracellular anabolic signaling molecules in a mammalian/mechanistic target of rapamycin (mTOR)‐dependent pathway. Results indicate that activation of p70S6k occurs within 2‐h following REX in experienced, resistance‐trained men. Further, results also suggest that highly trained, stronger individuals have an attenuated acute anabolic response.

Effects of 28-days ingestion of a slow-release energy supplement versus placebo on hematological and cardiovascular measures of health

Background

Recently, slow release tablets have been developed to prolong energy release throughout the day. The efficacy of the delivery of slow-release caffeine alone is fairly well documented; however, an assessment of safety and tolerability of prolonged use of slow-release energy supplements is lacking. Therefore the objective of this study was to investigate the effect of daily ingestion of a slow-release energy supplement for 28 days on blood chemistry and resting cardiovascular measures in healthy men and women.

Methods

Forty healthy individuals (20 males, 20 females; age: 22.73 ± 3.06 years; height: 171.68 ± 10.45 cm; mass: 74.49 ± 15.51 kg; BMI: 25.08 ± 3.66 (kg • m²) ^-1) participated in this randomized, double-blind, placebo controlled study. Following a 12-hour fast, participants reported for pre-testing. Testing consisted of resting heart rate (RHR) and blood pressure (BP) measures, followed by assessment of metabolic blood chemistry, blood lipids and complete cell counts. Participants then supplemented with either Energize™ (SUPP) or placebo (PL) for 28 days. Post-testing occurred 24-hours after ingestion of the final dose and consisted of the same protocol at the same time of day as pre-testing.

Results

No significant changes in outcome measures were observed. A significant difference between groups was observed for plasma glucose concentrations; however, follow-up testing revealed that pre- to post-supplementation changes were not significant for either SUPP or PL. All variables remained within normal adult reference ranges. No adverse events were reported.

Conclusions

These findings indicate that 28 consecutive days ingestion of a slow release energy supplement containing caffeine in caffeine users is both safe and tolerable.

C-terminal agrin fragment is inversely related to neuromuscular fatigue in older men

INTRODUCTION

The aim of this study was to examine the relationship between serum C-terminal agrin fragment (CAF) concentrations and neuromuscular fatigue in older adults.

METHODS

Twenty-two healthy older men and women volunteered for this study. Resting fasted blood samples were collected and prepared for measurement of serum CAF concentration by a commercially available ELISA kit. The onset of neuromuscular fatigue was measured by monitoring electromyographic fatigue curves from the vastus lateralis muscle using the physical working capacity at fatigue threshold (PWCFT ) test.

RESULTS

A significant inverse correlation for men was observed between CAF and PWCFT (r = -0.602; P = 0.05), but not for women (r = 0.208; P = 0.54). After controlling for age and body mass index, significant correlations (r = -0.69; P = 0.042) remained for men, but not for women (r = 0.12; P = 0.76).

CONCLUSIONS

These data suggest that serum CAF concentrations were significantly related to the onset of neuromuscular fatigue independent of age and BMI in men only.

Erythropoietin reduces the expression of myostatin in mdx dystrophic mice

Erythropoietin (EPO) has been well characterized as a renal glycoprotein hormone regulating red blood cell production by inhibiting apoptosis of erythrocyte progenitors in hematopoietic tissues. EPO exerts regulatory effects in cardiac and skeletal muscles. Duchenne muscular dystrophy is a lethal degenerative disorder of skeletal and cardiac muscle. In this study, we tested the possible therapeutic beneficial effect of recombinant EPO (rhEPO) in dystrophic muscles in mdx mice. Total strength was measured using a force transducer coupled to a computer. Gene expression for myostatin, transforming growth factor-β1 (TGF-β1), and tumor necrosis factor-α (TNF-α) was determined by quantitative real time polymerase chain reaction. Myostatin expression was significantly decreased in quadriceps from mdx mice treated with rhEPO (rhEPO=0.60±0.11, control=1.07±0.11). On the other hand, rhEPO had no significant effect on the expression of TGF-β1 (rhEPO=0.95±0.14, control=1.05±0.16) and TNF-α (rhEPO=0.73±0.20, control=1.01±0.09). These results may help to clarify some of the direct actions of EPO on skeletal muscle.

The anabolic androgenic steroid nandrolone decanoate disrupts redox homeostasis in liver, heart and kidney of male Wistar rats

The abuse of anabolic androgenic steroids (AAS) may cause side effects in several tissues. Oxidative stress is linked to the pathophysiology of most of these alterations, being involved in fibrosis, cellular proliferation, tumorigenesis, amongst others. Thus, the aim of this study was to determine the impact of supraphysiological doses of nandrolone decanoate (DECA) on the redox balance of liver, heart and kidney. Wistar male rats were treated with intramuscular injections of vehicle or DECA (1 mg.100 g⁻¹ body weight) once a week for 8 weeks. The activity and mRNA levels of NADPH Oxidase (NOX), and the activity of catalase, glutathione peroxidase (GPx) and total superoxide dismutase (SOD), as well as the reduced thiol and carbonyl residue proteins, were measured in liver, heart and kidney. DECA treatment increased NOX activity in heart and liver, but NOX2 mRNA levels were only increased in heart. Liver catalase and SOD activities were decreased in the DECA-treated group, but only catalase activity was decreased in the kidney. No differences were detected in GPx activity. Thiol residues were decreased in the liver and kidney of treated animals in comparison to the control group, while carbonyl residues were increased in the kidney after the treatment. Taken together, our results show that chronically administered DECA is able to disrupt the cellular redox balance, leading to an oxidative stress state.

Effects of β-hydroxy-β-methylbutyrate free acid and cold water immersion on post-exercise markers of muscle damage

The aim of the current study was to examine the effects of cold water immersion (CWI) with and without the free acid form of β-hydroxy-β-methylbutyrate (HMB-FA) on markers of muscle damage following acute lower body resistance exercise. Forty recreationally resistance-trained men (22.3 ± 2.4 years) were randomly divided into one of the four groups: (1) Placebo (PL); (2) HMB-FA; (3) HMB-FA-CWI; (4) PL-CWI. HMB-FA groups ingested 3 g day(-1) and CWI groups submersed their lower body into 10-12 °C water for 10-min post-exercise. No differences between groups were observed for CK; however, PL-CWI had significantly greater elevations in myoglobin 30-min post-exercise compared to HMB-FA (p = 0.009) and PL (p = 0.005), and HMB-FA-CWI was significantly greater than HMB-FA (p = 0.046) and PL (p = 0.028). No differences between groups were observed for IL-6 and IL-10, although CRP was significantly greater 24-h post-exercise for PL-CWI compared to HMB-FA-CWI (p = 0.02) and HMB-FA (p = 0.046). Only HMB-FA-CWI showed significantly (p = 0.02) greater improvements in average power per repetition. CWI appeared to elevate myoglobin compared to other groups, while HMB-FA may have attenuated the increase in CRP when combined with CWI. Nevertheless, HMB-FA or CWI treatments did not appear to provide benefit over PL for recovery. Instead, the combination of CWI and HMB-FA improved performance recovery compared to other groups.

Muscle architecture and strength: adaptations to short-term resistance training in older adults

INTRODUCTION

Muscle morphology and architecture changes in response to 6 weeks of progressive resistance training were examined in healthy older adults.

METHODS

In this randomized, controlled design, muscle strength, quality, and architecture were evaluated with knee extension, DEXA, and ultrasound, respectively, in 25 older adults.

RESULTS

Resistance training resulted in significant increases in strength and muscle quality of 32% and 31%, respectively. Cross-sectional area of the vastus lateralis increased by 7.4% (p ≤ 0.05). Physiological cross-sectional area (PCSA) of the thigh, a composite measure of muscle architecture, was related significantly to strength (r = 0.57; p ≤ 0.01) and demonstrated a significant interaction after training (p ≤ 0.05). Change in PCSA of the vastus lateralis was associated with change in strength independent of any other measure.

CONCLUSIONS

Six weeks of resistance training was effective at increasing strength, muscle quality, and muscle morphology in older adult men and women.

Obstrução intestinal em bovinos associada ao consumo de Stylosanthes sp. (Fabaceae Papilionoideae)

O objetivo deste trabalho é descrever, em três propriedades rurais no Estado de Mato Grosso, a epidemiologia, o quadro clínico e o patológico da obstrução intestinal por fitobezoares em bovinos que pastoreavam em piquetes com predomínio de Stylosanthes sp. pelo menos 60 dias. A morbidade variou de 3,3% a 15% e a mortalidade foi de 100%. O quadro clínico foi de cólica abdominal caracterizado por apatia, anorexia, inquietação, desconforto, sudorese e vocalização, seguido por episódios de diarreia ou diminuição da produção fecal, desidratação, hipomotilidade gastrintestinal, aumento do volume abdominal, decúbito esternal ou lateral com a cabeça voltada para o flanco e morte. O curso clínico foi de 2-7 dias. A principal alteração notada durante a necropsia dos bovinos foi a obstrução intestinal por fitobezoar ovoide de 2-5 cm de diâmetro, frequentemente no duodeno, próximo ao piloro, ocasionalmente em sua porção média. Na área de obstrução notou-se a necrose da parede intestinal que estava enegrecida e intensamente demarcada em relação a segmento adjacente normal, além de intenso espessamento associado a edema, congestão e hemorragia. O abomaso e os segmentos intestinais anteriores a obstrução apresentavam-se repletos de conteúdo alimentar líquido e posteriormente estava com ausência de conteúdo. O rúmen frequentemente tinha grande quantidade de conteúdo liquido a pastoso. Em todos os bovinos necropsiados múltiplas estruturas sólidas, arredondadas ou ovoides, esverdeadas (fitobezoares) foram observadas no abomaso. Estes achados indicam que pastagens com predomínio de Stylosanthes sp. predispõem a formação de fitobezoares, os quais podem levar à obstrução intestinal e morte em bovinos.