A Study Comparing Pre-Ingested L-Leucine and L-Isoleucine on Glycemic Responses in Healthy Inactive Adults: Preliminary Data.

Background The co-ingestion of amino acids with a glucose drink has been shown to blunt the elevated post-prandial glucose response. Though not entirely clear, some suggest amino acids will facilitate an incretin-driven insulin response that improves glucose sensitivity. Therefore, the purpose of this study is to examine the “priming” effect of pre-ingested amino acids on glycemic control in healthy inactive adults. We present here some preliminary data from 7 adults. Hypothesis We hypothesize that the pre-ingested amino acids would attenuate the post-prandial rise in glucose during a 75 g glucose tolerance test. Methods To test this, seven healthy adults (Females: n =4, Males: n=3, Age 27.17 ± 4.7 y; Height 165.84 ± 9.53 cm; Weight 82.47 ± 14.63 kg; BMI 30.14 ± 7.54 kg/m2; Lean body mass (LBM) 56.83 ± 20.56 kg; Fasting blood glucose (FBG) 87.43 ± 5.29 mg/dL) completed four trials in a randomized, single blinded fashion. The four trials required participants to ingest either Leucine (LEU), L-Isoleucine (ISO), an equal combination of LEU/ISO combined and lastly a control. Each treatment was ingested 30-min prior to a 2 h 75-g oral glucose tolerance test. The amino acid drink (200 mL) was standardized by the participant LBM (0.3g/kg) while the control consisted of inert stevia and non-amino acid ingredients found in equal amounts as other treatment mixtures (3.54 g). Venous blood samples were taken at baseline, and at 10, 30, 40, 60, 90, 120, and 150-min post-treatment and 75 g glucose drink. Because data collection is ongoing, the researchers are still blinded to the composition of the amino acid drinks and thus results are presented as: Red A, Green B, Yellow C, and control (White D). Plasma glucose (GLU) was analyzed using a YSI 2900 analyzer (Yellow Springs Instruments) and insulin (INS), glucagon (GCG), glucose-dependent insulinotropic peptide (GIP) and glucagon-like peptide-1 (GLP-1) concentrations were quantified by fluorescent bead-based technology (MAGPIX, Luminex xMAP technology). A 2-way RMANOVA was used to assess glucose data (Graphpad Software). Results Pre-ingestion of amino acid had no significant treatment effect on GLU compared to control (P = 0.5912). Currently, only 2 individuals have been analyzed for insulin, C-peptide, glucagon, GLP-1Active, and GIPTotal. However, we observed early and promising, non-statistical supported differences in concentrations between trials of insulin (Red A, Yellow C \u3e Green B, White D), GLP-1Active (Red A, Green B, Yellow C \u3e White D), and GIPTotal (Red A \u3e Green B, Yellow C, White D). Conclusion Based on these preliminary results, it appears that pre-ingestion of an amino acid drink does not influence glucose control in healthy and inactive young adults. It remains to be seen if pre-ingestion of the amino acids LEU and ISO, have any definitive effect on incretin secretion or subsequent insulin and glucagon responses

Replicating Intermittent Fasting in Human Skeletal Muscle Cells: A Pilot Study

Type 2 diabetes (T2D), the most common form of diabetes (90-95% of diagnoses), is marked by decreased insulin sensitivity (insulin resistance) or a defect in insulin secretion. T2D disrupts nutrient signaling where the body cannot maintain adequate blood glucose levels. Inability to receive glucose in skeletal muscle due to insulin resistance in T2D results in oxidative stress and increased muscle atrophy. Properly regulated glucose uptake is pivotal for healthy aging and maintenance of the skeletal muscle system. PURPOSE: The purpose of this study is to examine the effects of nutrient deprivation on human skeletal muscle metabolism, with an emphasis on oxidative stress and atrophy markers in healthy and T2D cell models. METHODS: Healthy human skeletal muscle myoblast cells (HSMM) and diabetic human skeletal muscle myoblast cells (DHSMM) (Lonza Inc, Walkersville MD) were cultured in a 37°C with 5% CO2 incubator in a T-75 flask. At confluency, cells were transferred into four 24-well plates and were incubated for 48h with standard culture media (Lonza Inc, Walkersville MD). The cells were then incubated for 12 or 24 h in media containing varying serum concentrations: 5%, 10%, and 15%. The media contained either fetal bovine serum (FBS) (Lonza Inc, Walkersville MD) or pooled human serum (HS) from either healthy or diabetic patients (Doctors Regional, Corpus Christi TX). Following the 24 hours, cell viability and density were determined, and sandwich enzyme-linked immunosorbent assay kits (RayBiotech, Norcross GA) were performed to measure the amount of superoxide dismutase (SOD1) present in each sample. RESULTS: A treatment effect was found using T2D HS which had a significant influence on mean SOD1 levels (range of SOD1 pg/mL; p=0.0423). There was no significant effect of time between 12h and 24h (p=0.1100). In the FBS models, a significant effect of concentration HSMM is seen (p=0.0263). Incubation time had little effect on FBS DHSMM (p=0.2671) and HSMM (p=0.2780) models. CONCLUSION: As serum concentration increases, the level of SOD1 present in the samples also increases. This suggests that treatment concentration may influence the activity of SOD1. This may be due to exogenous SOD1 already present in the serum. However, we did not asses the rate of appearance and decay of SOD1 already present in the serum. Incubation time shows little difference in all models. These results suggest that compositional environment can influence SOD1 levels and that a higher concentration may promote oxidative stress more so than a lower concentration environment

The Assessment of Hydration Status and Renal Markers Associated with Acute Kidney Injury in NCAA Division I Female Soccer Players During Preseason Training in South Texas: A Pilot Study

Recent research suggest that recurrent heat-associated dehydration and strenuous physical exertion may be associated with the development of acute and potentially chronic renal dysfunction. Typical South Texas environmental conditions in August, during preseason, on NCAA female college athletes may warrant concerns for promoting acute kidney injury (AKI). PURPOSE: The purpose of this study is to investigate hydration status and renal biomarkers in NCAA Division I female soccer athletes in South Texas during the preseason. METHODS: (Mean ± SEM; n = 12; age: 19.5 ± 0.9 y; ht: 167.6 ± 6.24 cm; wt: 66.6 ± 10.15 kg). Each subject participated in Pre-and post-body composition measures via DXA (iDXA, Lunar Prodigy), pre-, post-practice, and game weight changes (SECA Model 769); provided 14-urine samples throughout the preseason for hydration via Urine Specific Gravity (USG) and renal function Creatinine (UCr) ELISA analyses. Urine samples were collected prior to preseason (PRE-PS), fitness testing days (FT1, FT2), regular practices (MidW1, MidW2, POST-PS) and exhibition games (PRE-BU, POST-BU,12HR-BU, 24HR-BU, PRE-UT, POST-UT, 12HR-UT, 24HR-UT). Heat index was assessed at each practice session and exhibition match (Kestrel 5000; Kestrel Meters). RESULTS: 1-way ANOVA for USG analysis, a difference was found at MidW2 prior to the end of the POST-PS 1.018 ± .001 (p = .03; CI: 1.017-1.025) and early fitness testing values (FT1: 1.022 ± 0.005; FT2: 1.022 ± 0.006) and the MidW1 of the pre-season 1.025 ±.001; (p = .004; CI: 1.022 - 1.027). The BU game USG pre-measure was lower than post (POST-BU, 12 h and 24 h) \u3c p = .02; 1.01 ± .001; CI: 1.008 - 1.016), a difference was found during the UT game pre-measure compared to POST-UT and 12 h post values 1.009 ± .0016 (p = .0009; CI: 1.006 - 1.013) and no different than the 24 h POST-UT 1.014 ± .001. 2-way ANOVA ( x heat index x time) for UCr (mg· dL-1· LBM-1), a difference was found between PRE-BU and POST-BU (p = .001; CI: .448 - 3.81) and comparing PRE-UT to POST-UT (p = \u3c .0001; CI: 2.57 - 6.31) and 12HR-UT (p = \u3c .0001; CI: 2.09 - 5.21). CONCLUSION: Our current analysis suggests, the subjects were euhydrated prior to the exhibition games and hypohydrated 12-hours post-exhibition game, prior to fitness assessments (FT1, FT2), and regular morning practice (MidW1). UCr increased above normative values post-exhibition games. The increases in UCr may be independent of hydration status and muscle mass as euhydration was maintained post-exhibition matches

Proceedings of the Thirteenth International Society of Sports Nutrition (ISSN) Conference and Expo

Meeting Abstracts: Proceedings of the Thirteenth International Society of Sports Nutrition (ISSN) Conference and Expo Clearwater Beach, FL, USA. 9-11 June 201

The role of age in the physiological adaptations and psychological responses in bikini-physique competitor contest preparation: a case series

The increased popularity of the bikini-physique competitions has not translated to greater research identifying the influence of age on adaptations during contest preparation. The purpose of this case series was to observe how age may influence the adaptations normally seen during preparation and the exploration of newer protocols to address adaptations more relative to the judging standards. Over a 16-week pre-contest preparation, a 32-y bikini competitor (BC) and 44-y master’s bikini competitor (MBC) visited the laboratory bi-weekly to observe changes in body fat mass (BF), lean body mass (LBM), bone mineral density (BMD), total body water (TBW); exploratory measures of deltoid cross-sectional area (DeltCSA), gluteus maximus muscle thickness (GMMT), and subcutaneous adipose tissue thickness (SAT); reproductive hormones estradiol (E2), luteinizing hormone (LH), and energy balance hormones triiodothyronine (T3), leptin and ghrelin; hydration status during contest preparation and the week of competition; resting metabolic rate (RMR); psychometric data related to perceived anxiety, stress, and body image were assessed. No differences between BC and MBC were observed in BF, LBM, BMD, and TBW. Both competitors showed a small loss in LBM. Both BC and MBC showed a contrasting increase in DeltCSA and a loss in GMMT. MBC showed to be slightly more dehydrated (1.025 vs 1.021 g·mL− 1) than BC. Both competitors maintained a euhydration status the day of the competition. No time differences were found between BC and MBC during RMR. BC showed a higher mean difference RMR compared to MBC (2.66 ± 0.75 kcal·kgLBM− 1·d− 1). MBC showed a higher mean difference in LH concentration (84.6 ± 6.01 IU·L− 1), which may be explained by perimenopausal status. MBC had a higher mean difference concentration of leptin (2.51 ± 0.24 ng·mL− 1·kgFM− 1), which was unperturbed by fat loss may be interrelated LH. BC self-reported a higher mean energy intake (15.07 ± 3.43 kcal·kgLBM− 1·d− 1) and higher aerobic training volume (93.26 ± 40.68 min·d). BC and MBC showed similar composition changes, slightly differing metabolic rates, and differing hormonal LH and leptin responses. This finding is in contrast to previous work showing both LH inhibition and leptin diurnal disturbance in younger, female athletes with low energy availability. The exploratory measures may have some benefit for bikini-physique competitors related to the judging criteria. Age did not seem to play a role in contest preparation adaptations

The examination of a different range of motion (ROM) during the barbell-bench press exercises on glycolytic metabolism, muscle oxygenation and biomechanical measures of force and power

Introduction: Full range of motion (fROM) during resistance training (RT) is a traditionally recommended by professionals as approach for optimal strength and muscle adaptations. However, newer research has shown that partial range of motion (pROM) has similar benefits. Purpose: The purpose of this study is to investigate the effect of a range of motion (fROM vs. pROM) during both flat (FB) and incline (IB) barbell bench exercises press on acute markers of oxygen saturation (SmO2) of the pectoralis major (PM), blood lactate (BLa), and simple biomechanical markers of vertical distance (cm), peak force (N), absolute peak power (W), peak velocity (m/s), and relative power (W/kg). Methods: Two male and female subjects (Age:22.2±0.9y; Height:170.0±3.4cm; Weight:71.3±7.1kg; Body Fat:17.60±4.2%) were subsequently randomized to perform both ROM bouts during IB-bench press (45° incline) and FB-bench press utilizing a Smith Machine (SM) barbell machine. The SM barbell was adjusted per subject’s preferred arm length. 7-days prior to each ROM bout, strength testing (1RM) was completed to determine 75-80% intensity used for the subsequent ROM bouts. Pre-bout (Pre) and immediate post-bout (IP) BLa was measured as an indirect marker to determine glycolytic contribution. A Moxy Muscle Oxygen monitor was placed on the subjects right PM at 25% distal to the suprasternal notch to assess SmO2 (n=1). The biomechanical measures were collected using a commercially available GymAware PowerTool Linear position transducers (GLT) that directly measures the vertical displacement of a cable that was attached to the SM barbell and is expressed through and saved on an iPad. A one-way ANOVA was used to assess any preliminary differences. Results: Currently, no differences were found in BLa change ( ) and volume load (sets·reps·kg) (n=4); No differences were found in any biomechanical measure including vertical distance between conditions; SmO2 showed the lowest O2 saturation in the pROM-IB condition. Discussion/Conclusion: Currently, there are no differences found between conditions. However, this may be explained by loss of subject GymAware data due to recent update made to their application. No difference was found between conditionings in vertical distance. However, this could be explained by differing arm lengths of the participants. Lastly, a small sample size at this time limits any significant conclusions

The Impact of a Large Bolus Dose of l-leucine and l-isoleucine on Enteroendocrine and Pancreatic Hormones, and Glycemia in Healthy, Inactive Adults

Background: The ingestion of whey protein and amino acids with carbohydrate (CHO) enhances the release of glucagon-like peptide-1 (GLP-1) and glucose-dependent-insulinotropic peptide (GIP) that promote insulin secretion. It is unknown if L-isoleucine (Ile) and L-leucine (Leu) have this same effect. The purpose of this study was to examine how Ile and Leu influence both GLP-1 and GIP, subsequent pancreatic hormones, and glycemia in healthy, inactive adults. Methods: Twelve adults (6F/6M; age 27.4 ± 2 years; BMI 26.3 ± 2 kg/m2; lean body mass 53.2 ± 5 kg; body fat 34.1 ± 3%) completed four conditions in a randomized, cross-over fashion. Treatments standardized (0.3 g/kg·LBM−1) (1) Leu, (2) Ile, (3) Equal (1:1 g) of Leu + Ile, and (4) placebo (Pla, 3.5 g inert stevia) ingested 30 min prior to an oral glucose tolerance test (OGTT). Samples of plasma glucose, insulin, glucagon, GIPTotal, and GLP-1Active were assessed. Results: A treatment (p = 0.01) effect comparing Ile vs. Leu (p = 0.02) in GIPTotal. Area under the curve showed an increase in GIPTotal from Ile compared to Leu and Pla (p = 0.03). No effect was found on GLP-1. The ingestion of Ile prior to CHO augmented GIP concentration greater than Leu or Pla. No correlation was found between GIP, insulin, and glucose between conditions. Conclusions: Ile impacts GIP concentration, which did not relate to either insulin or glucose concentrations. Neither Ile, nor Leu seem to have an effect on hyperglycemia ingested prior to a CHO drink

The Effect of Acute and Chronic Thermotherapy on Type 2 Diabetic Skeletal Muscle Gene Expression and Inflammatory Markers

Background: Type 2 diabetes (T2D) is a chronic illness associated with resistance to or defective insulin secretion. This study investigates the effects of thermotherapy on cell viability, gene expression and inflammation in skeletal muscle cell lines. Methods: Healthy and T2D human skeletal muscle cell lines (HSMM and D-HSMM, respectively) were subjected to acute or chronic thermo-therapy (AT or CT, respectively). CT consisted of a 30 min exposure to 40 °C, three times a week for three weeks; AT was a one-time exposure. Results: A significant decrease in D-HSMM cell viability percentage followed AT; however, no significant change occurred in CT. HSMM yielded the highest elevations of genes following CT. In D-HSMM, both treatments yielded gene upregulation. Both treatments significantly down-regulated IL-1β, IL-6, IL-10 and TNF-α in HSMM. AT significantly decreased IL-1β, IL-6 and upregulated IL-10 and TNF-α levels in D-HSMM, while CT yielded a reduction in IL-4, TNF-α and an upregulation of IL-6 and IL-10. Conclusions: An increase in gene expression indicates actin activity and cellular responses, suggesting an increase in transcriptional regulation. The upregulation of IL-6 and IL-10 in D-HSMM negatively correlated with a decrease in TNF-α and IL-1β, indicating improved adverse inflammatory effects associated with the disease

The Impact of a Large Bolus Dose of L-leucine and L-isoleucine on Enteroendocrine and Pancreatic Hormones, and Glycemia in Healthy, Inactive Adults.

Background: The ingestion of whey protein and amino acids with carbohydrate (CHO) enhances the release of glucagon-like peptide-1 (GLP-1) and glucose-dependent-insulinotropic peptide (GIP) that promote insulin secretion. It is unknown if L-isoleucine (Ile) and L-leucine (Leu) have this same effect. The purpose of this study was to examine how Ile and Leu influence both GLP-1 and GIP, subsequent pancreatic hormones, and glycemia in healthy, inactive adults. Methods: Twelve adults (6F/6M; age 27.4 ± 2 years; BMI 26.3 ± 2 kg/m2; lean body mass 53.2 ± 5 kg; body fat 34.1 ± 3%) completed four conditions in a randomized, cross-over fashion. Treatments standardized (0.3 g/kg·LBM−1) (1) Leu, (2) Ile, (3) Equal (1:1 g) of Leu + Ile, and (4) placebo (Pla, 3.5 g inert stevia) ingested 30 min prior to an oral glucose tolerance test (OGTT). Samples of plasma glucose, insulin, glucagon, GIPTotal, and GLP-1Active were assessed. Results: A treatment (p = 0.01) effect comparing Ile vs. Leu (p = 0.02) in GIPTotal. Area under the curve showed an increase in GIPTotal from Ile compared to Leu and Pla (p = 0.03). No effect was found on GLP-1. The ingestion of Ile prior to CHO augmented GIP concentration greater than Leu or Pla. No correlation was found between GIP, insulin, and glucose between conditions. Conclusions: Ile impacts GIP concentration, which did not relate to either insulin or glucose concentrations. Neither Ile, nor Leu seem to have an effect on hyperglycemia ingested prior to a CHO drink

The effect of acute thermotherapy on type 2 diabetic skeletal muscle gene expression

Type 2 Diabetes (T2D) is among the chronic diseases increasingly affecting the human population. This disease potentially results in the interruption in the production of insulin and/or the dysregulation of insulin signaling which may facilitate skeletal muscle mass loss. Exercise is a known stimulus of muscle mass gain or retention. During exercise, skeletal muscle temperature increases (~39°C), however, it is unknown if this in- crease in temperature alone may influence the transcriptome related to skeletal muscle growth. PURPOSE: The aim of this study was to identify if thermotherapy (heat stress mimetic) may influence genes related to muscle growth and atrophy. METHODS: Human Skeletal Muscle Myoblasts (HSMM) and Diabetic Type 2 Human Skeletal Myoblast (D-HSMM) were purchased from Lonza Inc. (Lonza Inc, Walkersville, MS). HSMM and D-HSMM were cultured until reaching a confluency of 70-80%. Both D-HSMM and HSMM were exposed to an acute bout of thermotherapy (40°C) in experimental well plates. All well plates were treated at a one-time for 30 min. Control well plates were kept at 37°C. The experimental well plates were treated for 24 hours following an initial 48-hour incubation at 37°C. Post-thermotherapy treatment consisted of cell observation, cell viability, and preparation for gene expression. To perform gene expres- sion, RNA was isolated from D-HSMM and HSMM, converted to cDNA, and a real-time polymerase chain reaction (qRT-PCR) was used to assess Activin-A Receptor Type 2B (ACVR2B) and b-catenin (CTNNB1) to a housekeeping gene (GAPDH). RESULTS: Following gene expression analysis, it was determined that ACVR2B yielded the highest change (~1-fold) in D-HSMM. For HSMM, CTNNB1 yielded the highest change (~1-fold). CONCLUSION: These preliminary results suggest that ACVR2B expression, which is the prime myostatin receptor during thermotherapy could potentially facilitate greater muscle atrophy in T2D skeletal muscle. However, the thermotherapy-induced increase in CTNNB1 expression in the normal, healthy skeletal muscle cells may suggest greater androgen receptor (AR) activation and a role in skeletal muscle growth due to the reported actions of b-catenin on AR activation