Podiatry Management (October, 2010) has just published an article I’ve written titled  Overuse Injuries: All The Small Things . You are just another click away from the PDF version. This is a challenging article. It introduces mechanotransduction, a theory of cellular and tissue function, which is little known in the sports medicine community. The article touches lightly on this topic and then reviews the latest literature and theory on overuse injuries to bone and tendon.

The Needle - Kenneth Snelson

The cellular level is where things start and where we will find many answers. I expect to add more details on the web site on mechanotransduction and mechanobiology for those with hardcore, deep science interest. The article is limited in size, but was longer than many published in PM Magazine. But, I didn’t even touch on the theory canalicular flow and osteocyte induction or mechanotransduction and control of stem cell development by matrix stiffness. Research in the field of mechanobiology is growing daily and the outlook is great that it will be fruitful.

Many people have played the facebook game “What’s Your Real Age”. My guess that those who played it wanted to feel they were younger than their biological age. Telomere length seems to be the real way to determine actual “biological age”. These are the real “biological clocks”. Telomeres are repetitive sequences at the ends of chromosomes that shorten with age and also shorten in certain metabolic and disease states. They are sometimes called the protective “caps” on the ends of chromosomes. Because of the manner in which chromosomes are replicated during cellular division, a bit of the telomere is not copied with each subsequent cellular generation resulting in a gradual shortening of the telomere restriction fragment (TRF) length.

Telomeres Shorten With Age

A recent study showed that people who perform more leisure time physical activity have longer telomeres. Another recent study, with an admitted low subject number, demonstrated that eating processed meat  such as sliced bologna would also slice down the size of your telomeres. This study, published in the American Journal of Clinical Nutrition did not find other expected dietary associations.

The Cardiovascular Health Study (2007) found inverse correlations (shortened telomeres) between TRF length and fasting glucose level, fasting insulin level, systolic and diastolic blood pressure, carotid intima-media thickness, interleukin-6, high BMI, overweight (in men).

Some studies including one with “voluntary running” in mice showed the production of telomere protective compounds with the “voluntary” running. On a side note,  I’ll have to look closer at this study. If we can can get mice to  voluntarily participate in a “fitness” program, maybe we can figure out the secret to get more people to do so. Perhaps cheese is the answer.

Aubert and Lansdorp (2008) published an excellent review of  the biology of telomeres and aging. They noted that Barbara McClintock, in her 1983 Nobel acceptance speech pointed out the significance of cellular response to stress and dangers. “In the future attention undoubtedly will be centered on the genome, and with greater appreciation of its significance as a highly sensitive organ of the cell, monitoring genomic activities and correcting common errors, sensing the unusual and unexpected events, and responding to them, often by restructuring the genome. We know about the components of genomes that could be made available for such restructuring. We know nothing, however, about how the cell senses danger and instigates responses to it that often are truly remarkable.”

Short Telomeres Trigger Cellular Defences

The shortened telomeres are likely sending more “damage” signals to the cells which lead to a number of biochemical pathways which degrade the contents of the cell. Studies on cellular senescence, apoptosis, and research on genomics is leading us to a better understanding, but we have a long ways to go. The complexity never ends, but it continues to unwind. And you can almost hear the tick tock of the biological clock. Your best means of slowing up the ticking are life habit changes: exercise regularly, maintain healthy body weight, don’t smoke and eat a healthy diet.
What’s my age again? – Blink 182

What's My Age Again?

References:

Lynn F. Cherkas, PhD; Janice L. Hunkin, BSc; Bernet S. Kato, PhD; J. Brent Richards, MD; Jeffrey P. Gardner, PhD; Gabriela L. Surdulescu, MSc; Masayuki Kimura, MD, PhD; Xiaobin Lu, MD; Tim D. Spector, MD, FRCP; Abraham Aviv, MD. Arch Intern Med. 2008;168(2):154-158.

Annette L. Fitzpatrick1, Richard A. Kronmal2, Jeffrey P. Gardner3, Bruce M. Psaty1,4, Nancy S. Jenny5, Russell P. Tracy5,6, Jeremy Walston7, Masyuki Kimura3 and Abraham Aviv . Leukocyte Telomere Length and Cardiovascular Disease in the Cardiovascular Health Study. American Journal of Epidemiology 2007 165(1):14-21; doi:10.1093/aje/kwj346.

J. A Nettleton, A. Diez-Roux, N. S Jenny, A. L Fitzpatrick, and D. R Jacobs Jr. Dietary patterns, food groups, and telomere length in the Multi-Ethnic Study of Atherosclerosis (MESA). Am. J. Clinical Nutrition, November 1, 2008; 88(5): 1405 – 1412

Liza S.M. Wong, Hisko Oeseburg, Rudolf A. de Boer, Wiek H. van Gilst, Dirk J. van Veldhuisen and Pim van der Harst.. Telomere biology in cardiovascular disease: the TERC–/– mouse as a model for heart failure and ageing. Cardiovascular Research 2009 81(2):244-252; doi:10.1093/cvr/cvn337

Aubert, G. and P. M. Lansdorp (2008). “Telomeres and Aging.” Physiol. Rev. 88(2): 557-579.