|HBO > T = ? | too good to be true?|
Actually I wasn't too far off with the "mass monster".
I mean, as a SuppVersity reader you know that skeletal muscle hypertrophy, i.e. the expansion of existing muscle cells is limited by a natural cap to the size of the myonuclear domains, i.e. the muscle area / volume one of the myriad of cell kernels (=nuclei) in your muscles can manage. The only solution to grow beyond these natural limits is...? Correct! To add new myonuclei (=cell kernels).
These new myonuclei are recruited from the satellite cell pool, a reservoir of muscle stem cells. The main purpose of this "pool", however, is the maintenance, not the expansion of the muscle mass.
From regeneration to growth
In the real world we evolved in, "being a mass monster" was yet more of a hindrance than a help. A huge quantity of skeletal muscle is energetically costly and could - in the worst case scenario - slow you down so much that the next best sabertooth whose muscle power even the biggest "mass monster" cannot match would hunt you down.
In reality, the majority of satellite cells that move from the sarcoplasma (the "fluid" around the muscle") into the muscle is not going to contribute to skeletal muscle growth directly. Most of them simply replace damaged / dead myonuclei to ensure that the muscle keeps functional. It is this repair process, or rather the effect of a high pressure (=hyperbaric) high oxygen environment (HBO treatment) on its evolution that intrigued Horie M, Enomoto M, Shimoda M, Okawa A, Miyakawa S, and Yagishita K.
|Figure 1: HBO speeds up muscle both strength and size recovers (Gregorevic. 2002)|
Don't do this at home! While the scenario is completely different, papers such as Palmquist's, Phillip's and Barr's case report in the British Journal of Ophthalmology, in which the authors report for the first time that the well-known, temporary and reversible lens myopia that occurs in response to prolonged hyperbaric oxygen therapy may be complemented by cataractogenic effects, when the patients are exposed to 150 or more sessions of HBO (Palmquist. 1984). The most recent review of the literature says, though, that these side effects have been observed mostly in elderly or sick patients and that "the pressure and duration of exposures used in clinical practice, ocular complications do not seem to be a problem in HBO therapies." (Oguz. 2008) Still, the general risk of DNA through oxidative damage from the pure oxygen environment is real and should requires further investigation in realistic long(er) term scenarios (Ishii. 2005).If you're now asking yourselves, why this is the first time that you hear of this kind of treatment, you may want to take into consideration that the currently available human "studies have been limited due to the small sample size, lack of blinding and randomization problems" (Barato. 2011). Despite the fact that it is "promising" treatment for for injury recovery in high performance athletes, Barato et al. end their review the effects of hyperbaric oxygen therapy of sports injuries with a demand for
"larger samples, randomized, controlled, double-blinded clinical trials combined with studies using animal models so that its effects and mechanisms can be identified to confirm that it is a safe and effective therapy for the treatment of sports injuries." (Barato. 2011)With the publication of Horie's paper "Hyperbaric oxygen effects on sports injuries" (Hori. 2014) we have fulfilled demand #2. What we are still lacking, though is evidence from large-scale, randomized, controlled, double-blinded clinical trials that would support that exposing injured athletes into a pressure chamber with 100% oxygen under 2.5 atmospheres absolute for 2 h/day, 5 days/wk for 2 wk will trigger the same increases in satellite cell activity (MyoD, myogenin), incorporation (increased numbers of "young" muscle cells) and IGF-1 Horie et al. observed in their latest rodent study.
- Abidia, A., et al. "The role of hyperbaric oxygen therapy in ischaemic diabetic lower extremity ulcers: a double-blind randomised-controlled trial." European journal of vascular and endovascular surgery 25.6 (2003): 513-518.
- Barata, Pedro, et al. "Hyperbaric oxygen effects on sports injuries." Therapeutic advances in musculoskeletal disease 3.2 (2011): 111-121.
- Brown, D. Ross, et al. "A multicenter review of the treatment of major truncal necrotizing infections with and without hyperbaric oxygen therapy." The American journal of surgery 167.5 (1994): 485-489.
- Dulai, Parambir, et al. "P-135 Hyperbaric Oxygen Therapy for the Treatment of Inflammatory Bowel Disease: A Systematic Review." Inflammatory Bowel Diseases 19 (2013): S77-S78.
- Gregorevic, Paul, Gordon S. Lynch, and David A. Williams. "Hyperbaric oxygen improves contractile function of regenerating rat skeletal muscle after myotoxic injury." Journal of Applied Physiology 89.4 (2000): 1477-1482.
- Gregorevic, P., David A. Williams, and Gordon S. Lynch. "Hyperbaric oxygen increases the contractile function of regenerating rat slow muscles." Medicine and science in sports and exercise 34.4 (2002): 630-636.
- Horie, Masaki, et al. "Enhancement of satellite cell differentiation and functional recovery in injured skeletal muscle by hyperbaric oxygen treatment." Journal of applied physiology (Bethesda, Md.: 1985) (2013).
- Ishii, Yoshimasa, et al. "Hyperbaric oxygen as an adjuvant for athletes." Sports Medicine 35.9 (2005): 739-746.
- Moen, Ingrid, and Linda EB Stuhr. "Hyperbaric oxygen therapy and cancer—a review." Targeted oncology 7.4 (2012): 233-242.
- Moskowitz, Ari, Yu-Feng Yvonne Chan, and Aneesh B. Singhal. "Normobaric and Hyperbaric Oxygen Therapy for Ischemic Stroke and Other Neurological Conditions." Chemistry and Biochemistry of Oxygen Therapeutics: From Transfusion to Artificial Blood (2011): 159.
- Oguz, Halit, and Gungor Sobaci. "The use of hyperbaric oxygen therapy in ophthalmology." Survey of ophthalmology 53.2 (2008): 112-120.
- Palmquist, Britt-Marie, B. Philipson, and P. O. Barr. "Nuclear cataract and myopia during hyperbaric oxygen therapy." British journal of ophthalmology 68.2 (1984): 113-117.