Exertional rhabdomyolysis in a 21-year-old, healthy female after performing three sets of the biceps curl exercise to failure with 30% 1RM: A case report

Background: The optimal resistance training program to elicit muscle hypertrophy has been consistently debated and researched. Although 3 sets of 10 repetitions at 70-80% of the 1-repetition maximum (1RM) is widely recommended, recent studies have shown that low-load (~30% 1RM), high-repetition (3 sets of 30-40 repetitions) resistance training can elicit similar muscular hypertrophy. Therefore, this type of resistance training has gained popularity, perhaps because less weight is lifted for a longer duration. In the process of testing this hypothesis in a research study in our laboratory, a subject diagnosed with exertional rhabdomyolysis after completing a single resistance training session that involved 3 sets to failure at 30% 1RM. Exertional rhabdomyolysis is a condition characterized by the excessive breakdown of striated skeletal muscle that releases proteins from the muscle cell, particularly myoglobin, into the blood that can be toxic to the kidneys and is a significant health concern. Case Report: Reviewed were the events leading up to and throughout the diagnosis of exertional rhabdomyolysis in a healthy, recreationally-trained, 21-year-old female that was enrolled in a study that compared the acute effects of the traditional high-load, low-repetition versus low-load, high-repetition resistance training. The subject completed a total of 143 repetitions of the bilateral dumbbell bicep curl exercise. Three days post-exercise she reported excessive muscle soreness and swelling and sought medical attention. She was briefly hospitalized and then discharged with instructions to take acetaminophen for soreness, drink plenty of water, rest, and monitor her creatine kinase (CK) concentrations. Changes in the subject’s CK concentrations, ultrasound-determined muscle thickness and echo intensity were monitored over a 14-day period are reported. Discussion: This case illustrates the potential risk of developing exertional rhabdomyolysis after a low-load, high-repetition resistance training session in healthy, young, recreationally-trained women. The fact that exertional rhabdomyolysis is a possible outcome is enough to warrant caution when prescribing this type of resistance exercise

The effects of anatabine on non-invasive indicators of muscle damage: a randomized, double-blind, placebo-controlled, crossover study

Background: Anatabine (ANA), a minor tobacco alkaloid found in the Solanaceae family of plants, may exhibit anti-inflammatory activity, which may be useful to aid in recovery from exercise-induced muscle damage. The purpose of this study, therefore, was to examine the effects of ANA supplementation on the recovery of isometric strength and selected non-invasive indicators of muscle damage. Methods: A double-blinded, placebo-controlled, crossover design was used to study eighteen men (mean ± SD age = 22.2 ± 3.1 yrs; body mass = 80.3 ± 15.7 kg) who participated in two randomly-ordered conditions separated by a washout period. The ANA condition consisted of consuming 6–12 mg anatabine per day for 10 days, while testing took place during days 7–10. The placebo (PLA) condition was identical except that the PLA supplement contained no ANA. Maximal voluntary isometric peak torque (PT) of the forearm flexors, arm circumference, hanging joint angle, and subjective pain ratings were measured before (PRE), immediately after (POST), and 24, 48, and 72 h after six sets of 10 maximal, eccentric isokinetic forearm flexion muscle actions. Resting heart rate and blood pressure were measured at PRE and 72 h in each condition. Results: For PT, hanging joint angle, arm circumference, and subjective pain ratings, there were no condition x time (p \u3e 0.05) interactions, there were no main effects for condition (p \u3e 0.05), but there were main effects for time (p \u3c 0.001). There were no condition x time (p \u3e 0.05) interactions and no main effects for condition (p \u3e 0.05) or time (p \u3e 0.05) for blood pressure or resting heart rate. Conclusions: ANA supplementation had no effect on the recovery of muscle strength, hanging joint angle, arm swelling, or subjective pain ratings after a bout of maximal eccentric exercise in the forearm flexors. Therefore, ANA may not be beneficial for those seeking to improve recovery from heavy eccentric exercise. Future studies should examine the effects of ANA on the pro-inflammatory cytokine responses to exercise-induced muscle damage and the chronic low-grade inflammation observed in obese and elderly individuals

Chinese hamster ovary cells can produce galactose-α-1,3-galactose antigens on proteins

Chinese hamster ovary (CHO) cells are widely used for the manufacture of biotherapeutics, in part because of their ability to produce proteins with desirable properties, including 'human-like' glycosylation profiles. For biotherapeutics production, control of glycosylation is critical because it has a profound effect on protein function, including half-life and efficacy. Additionally, specific glycan structures may adversely affect their safety profile. For example, the terminal galactose-α-1,3-galactose (α-Gal) antigen can react with circulating anti α-Gal antibodies present in most individuals. It is now understood that murine cell lines, such as SP2 or NSO, typical manufacturing cell lines for biotherapeutics, contain the necessary biosynthetic machinery to produce proteins containing α-Gal epitopes. Furthermore, the majority of adverse clinical events associated with an induced IgE-mediated anaphylaxis response in patients treated with the commercial antibody Erbitux (cetuximab) manufactured in a murine myeloma cell line have been attributed to the presence of the α-Gal moiety. Even so, it is generally accepted that CHO cells lack the biosynthetic machinery to synthesize glycoproteins with α-Gal antigens. Contrary to this assumption, we report here the identification of the CHO ortholog of N-acetyllactosaminide 3-α-galactosyltransferase-1, which is responsible for the synthesis of the α-Gal epitope. We find that the enzyme product of this CHO gene is active and that glycosylated protein products produced in CHO contain the signature α-Gal antigen because of the action of this enzyme. Furthermore, characterizing the commercial therapeutic protein abatacept (Orencia) manufactured in CHO cell lines, we also identified the presence of α-Gal. Finally, we find that the presence of the α-Gal epitope likely arises during clonal selection because different subclonal populations from the same parental cell line differ in their expression of this gene. Although the specific levels of α-Gal required to trigger anaphylaxis reactions are not known and are likely product specific, the fact that humans contain high levels of circulating anti-α-Gal antibodies suggests that minimizing (or at least controlling) the levels of these epitopes during biotherapeutics development may be beneficial to patients. Furthermore, the approaches described here to monitor α-Gal levels may prove useful in industry for the surveillance and control of α-Gal levels during protein manufacture.National Center for Research Resources (U.S.) (Grant P41 RR018501-01

Exertional rhabdomyolysis in a 21-year-old, healthy female after performing three sets of the biceps curl exercise to failure with 30% 1RM: A case report

Background: The optimal resistance training program to elicit muscle hypertrophy has been consistently debated and researched. Although 3 sets of 10 repetitions at 70-80% of the 1-repetition maximum (1RM) is widely recommended, recent studies have shown that low-load (~30% 1RM), high-repetition (3 sets of 30-40 repetitions) resistance training can elicit similar muscular hypertrophy. Therefore, this type of resistance training has gained popularity, perhaps because less weight is lifted for a longer duration. In the process of testing this hypothesis in a research study in our laboratory, a subject diagnosed with exertional rhabdomyolysis after completing a single resistance training session that involved 3 sets to failure at 30% 1RM. Exertional rhabdomyolysis is a condition characterized by the excessive breakdown of striated skeletal muscle that releases proteins from the muscle cell, particularly myoglobin, into the blood that can be toxic to the kidneys and is a significant health concern. Case Report: Reviewed were the events leading up to and throughout the diagnosis of exertional rhabdomyolysis in a healthy, recreationally-trained, 21-year-old female that was enrolled in a study that compared the acute effects of the traditional high-load, low-repetition versus low-load, high-repetition resistance training. The subject completed a total of 143 repetitions of the bilateral dumbbell bicep curl exercise. Three days post-exercise she reported excessive muscle soreness and swelling and sought medical attention. She was briefly hospitalized and then discharged with instructions to take acetaminophen for soreness, drink plenty of water, rest, and monitor her creatine kinase (CK) concentrations. Changes in the subject’s CK concentrations, ultrasound-determined muscle thickness and echo intensity were monitored over a 14-day period are reported. Discussion: This case illustrates the potential risk of developing exertional rhabdomyolysis after a low-load, high-repetition resistance training session in healthy, young, recreationally-trained women. The fact that exertional rhabdomyolysis is a possible outcome is enough to warrant caution when prescribing this type of resistance exercise

Effects of a pre-workout supplement on hyperemia following leg extension resistance exercise to failure with different resistance loads

Abstract Background We sought to determine if a pre-workout supplement (PWS), containing multiple ingredients thought to enhance blood flow, increases hyperemia associated with resistance training compared to placebo (PBO). Given the potential interaction with training loads/time-under-tension, we evaluated the hyperemic response at two different loads to failure. Methods Thirty males participated in this double-blinded study. At visit 1, participants were randomly assigned to consume PWS (Reckless™) or PBO (maltodextrin and glycine) and performed four sets of leg extensions to failure at 30% or 80% of their 1-RM 45-min thereafter. 1-wk. later (visit 2), participants consumed the same supplement as before, but exercised at the alternate load. Heart rate (HR), blood pressure (BP), femoral artery blood flow, and plasma nitrate/nitrite (NOx) were assessed at baseline (BL), 45-min post-PWS/PBO consumption (PRE), and 5-min following the last set of leg extensions (POST). Vastus lateralis near infrared spectroscopy (NIRS) was employed during leg extension exercise. Repeated measures ANOVAs were performed with time, supplement, and load as independent variables and Bonferroni correction applied for multiple post-hoc comparisons. Data are reported as mean ± SD. Results With the 30% training load compared to 80%, significantly more repetitions were performed (p  0.05). NIRS derived minimum oxygenated hemoglobin (O2Hb) was lower in the 80% load condition compared to 30% for all rest intervals between sets of exercise (p < 0.0167). HR and BP did not vary as a function of supplement or load. Femoral artery blood flow at POST was higher independent of exercise load and treatment. However, a time*supplement*load interaction was observed revealing greater femoral artery blood flow with PWS compared to PBO at POST in the 80% (+56.8%; p = 0.006) but not 30% load condition (+12.7%; p = 0.476). Plasma NOx was ~3-fold higher with PWS compared to PBO at PRE and POST (p < 0.001). Conclusions Compared to PBO, the PWS consumed herein augmented hyperemia following multiple sets to failure at 80% of 1-RM, but not 30%. This specificity may be a product of interaction with local perturbations (e.g., reduced tissue oxygenation levels [minimum O2Hb] in the 80% load condition) and/or muscle fiber recruitment