Creatine: More than just boosting strength

Title: Dietary creatine monohydrate supplementation increases satellite cell mitotic activity during compensatory hypertrophy.

Researchers: Dangott B, Schultz E, Mozdziak PE.
Institution: Department of Anatomy, University of Wisconsin-Medical School, Madison, USA.

Source: International Journal of Sports Medicine 2000 Jan;21(1):13-6.

Summary: Nutritional status influences muscle growth and athletic performance, but little is known about the effect of nutritional supplements, such as creatine, on satellite cell mitotic activity. The purpose of this study was to examine the effect of oral creatine supplementation on muscle growth, compensatory hypertrophy, and satellite cell mitotic activity.

Methods: Compensatory hypertrophy was induced in the rat plantaris muscle by removing the soleus and gastrocnemius muscles. Immediately following surgery, a group of six rats was provided with elevated levels of creatine monohydrate in their diet. Another group of six rats was maintained as a non-supplemented control group. Twelve days following surgery, all rats were implanted with mini-osmotic pumps containing the thymidine analog 5-bromo-2'-deoxyuridine (BrdU) to label mitotically active satellite cells. Four weeks after the initial surgery the rats were killed, plantaris muscles were removed and weighed. Subsequently, BrdU-labeled and non-BrdU-labeled nuclei were identified on enzymatically isolated myofiber segments.

Results: Muscle mass and myofiber diameters were larger in the muscles that underwent compensatory hypertrophy compared to the control muscles, but there were no differences between muscles from creatine-supplemented and non-creatine-supplemented rats. Similarly, compensatory hypertrophy resulted in an increased number of BrdU-labeled myofiber nuclei, but creatine supplementation in combination with compensatory hypertrophy resulted in a higher number of BrdU-labeled myofiber nuclei compared to compensatory hypertrophy without creatine supplementation.

Conclusion: Creatine supplementation in combination with an increased functional load results in increased satellite cell mitotic activity compared to increased functional load alone.

Discussion: People seem to want to pigeonhole creatine into some sort of hit-or-miss water-retention supplement. Creatine is so much more than that. Creatine is truly one of the greatest supplements there is for building muscle and strength. Study after study attest to this fact. This is only one of many studies exploring the exciting anabolic properties of creatine monohydrate which we will consider in upcoming issues.

In short, creatine is a naturally occurring compound made within our own bodies. It is also found in many foods we eat, especially meat. Creatine monohydrate has been used as a dietary supplement for at least a decade now, though it was first discovered nearly 170 years ago.
Now in the study we're considering today, the examined the effect of dietary creatine monohydrate on satellite cell activity and subsequent muscle hypertrophy. I won't lie to you and tell you that I have no interest in educating Hypertrophy-Specific readers about creatine. On the contrary, I believe so highly in the effectiveness of creatine that I introduced it into the HSN line of products. Not because people demanded it, but instead because I believe in it. And taking a look at the available research on creatine will make you a believer too. The writing is on the wall with this one folks.

This study looked at the activity of satellite cells. Satellite cells are myogenic stem cells that make hypertrophy of adult skeletal muscle possible. These stem cells are simply generic or non-specific cells that have the ability to transform themselves into new muscle cells when they are instructed to.

Following proliferation (reproduction) and subsequent differentiation (to become a specific type of cell), these satellite cells will fuse with one another or with the adjacent damaged muscle fiber, thereby increasing myonuclei numbers necessary for fiber growth and repair.

In order to better understand what is physically happening between satellite cells and muscle cells, try to picture 2 oil droplets floating on water. The two droplets represent a muscle cell and a satellite cell. Because the lipid bilayer of cells are hydrophobic just like common oil droplets, when brought into proximity to one another in an aqueous environment, they will come into contact for a moment and then fuse together to form one larger oil droplet. Now whatever (i.e. nuclei) was within one droplet will then mix with the contents of the other droplet. This is a simplified model of how satellite cells donate nuclei to existing muscle cells.

The reason this finding about creatine is so exciting is that the process of satellite cells adding nuclei to regenerating muscle cells appears to be critical for hypertrophy. There appears to be a finite limit placed on the cytoplasmic/nuclear ratio (Rosenblatt,1994). This is the ratio of the volume of the muscle cell to the number of nuclei. Whenever a muscle grows in response to functional overload there is a positive correlation between the increase in the number of myonuclei and the increase in fiber cross sectional area (CSA). When satellite cells are prohibited from donating their nuclei, overloaded muscle simply will not grow (Rosenblatt,1992; Phelan,1997).

This study was able to show that creatine supplementation increased the number of myonuclei donated from satellite cells. This increases the potential for growth of those fibers due to the aforementioned cytoplasmic/nuclear ratio. This isncrease in myonuclei probably stems from creatine's ability to increase levels of the myogenic transcription factor MRF4 (Hespel, 2001).
So when it comes to answering the question, "what works and what doesn't" stick to those supplements that have real research behind them. Creatine, proteins, and essential fatty acids top the list of highly researched, highly effective supplements.

Reference: http://www.hypertrophy-specific.com/HSreport/iss03/