Testosterone May Strengthen ACL

New research by Romani et al. from The John Hopkins University in Baltimore has been published in The Knee and has shown that testosterone levels can have an impact on the strength of the anterior cruciate ligament (ACL). Romani’s previous research has shown that estrogen could reduce ACL strength.

The most recent study was performed on male rats. The ACLs of normal rats were compared to those of castrated rats. The testosterone levels in the castrated rats was close to zero. The researchers concluded that “rats with normal circulating testosterone had higher ACL load-to-failure and ultimate stress, indicating that testosterone may influence ACL strength and the injury rate of the ligament“. The results suggest that testosterone may help to strengthen the ACL. If coupled with the findings that estrogen could weaken the ACL, we can start to understand some of the reasons behind the differences in prevalence of ACL injuries between the sexes. Obviously, this only holds if these findings are the same in humans as well. It would also be interesting to know if these findings apply to other ligaments.

Smoking Causes Inflammation

It’s been known for a while that smoking decreases blood flow and hence reduces the transport of oxygen and other nutrients to tissues. But recent research by Ava Hosseinzadeh et al from the University of Umea in Sweden has looked into its effects on inflammation. Their findings were published in the Journal of Leucocyte Biology. They found that nicotine induces neutrophils to release neutrophil extracellular traps (NETs). NETs surround and destroy microbial pathogens but they can also lead to excessive inflammation and tissue damage. Obviously, it’s the excessive inflammation and tissue damage that’s of concern and it provides yet another reason to stop smoking.

Physical Activity and Health

A group of researchers led by Per Ladenvall (University of Gothenburg in Sweden) have looked into the relationship between physical capacity and health. They studied 800 middle-aged men over a period of 45 years. Physical fitness was measured by VO2 max. The results showed that low physical fitness is a greater risk of death than high blood pressure or cholesterol. It was second only to smoking as a risk of death.

Several studies have linked prolonged sitting with increased risk of mortality. A meta-analysis of data from over a million people was recently conducted by Ekeland et al. They wanted to find out if physical activity could attenuate, or even eliminate, the detrimental association of sitting time with mortality. They found that “high levels of moderate intensity physical activity (about 60–75 min/day) seem to eliminate the increased risk of death associated with high sitting time. However, this high activity level attenuates, but does not eliminate the increased risk associated with high TV-viewing time”.

Once again, the benefits of physical activity and physical fitness are clear. It’s up to us to make it a priority to move more, whether it’s through structured exercise or simply through the activities of daily living.

Sleep Deprivation Can Negatively Affect Cholesterol Levels And Inflammation

Vilma Aho et al from the University of Helsinki conducted 2 studies looking into the effects of sleep deprivation. The first study was experimental and consisted of partial sleep restriction to a small group of subjects. The second was an epidemiological study with over 2700 individuals. Blood samples were analysed in both cases.

The analyses revealed decreased circulating High Density Lipoproteins (HDL cholesterol), otherwise known as ‘good cholesterol’, and elevated inflammatory markers. Sleep loss decreased the expression of genes encoding cholesterol transporters and increased expression in pathways involved in inflammatory responses. The findings help to explain why sleep deprivation is a risk factor for cardiometabolic disease.

Why Is Calcific Tendinitis So Painful?

There are a couple of shoulder conditions that can be extremely painful. One is adhesive capsulitis, better known as frozen shoulder, and the other is calcific tendinitis. Calcific tendinitis is characterised by the formation of calcium deposits in the rotator cuff tendons of the shoulder. A few months ago Hackett et al from the University of New South Wales published the results of a study that could explain why calcific tendinitis is so painful. Their findings are published in The Journal of Bone & Joint Surgery.

They concluded that there was “a significant increase in neovascularization and neoinnervation in calcific tendinitis lesions of the shoulder along with an eightfold increase in mast cells and macrophages. The findings are consistent with the hypothesis that, in calcific tendinitis, the calcific material is inducing a vigorous inflammatory response within the tendon with formation of new blood vessels and nerves”.

Persistent Pain Associated With DNA Changes In Brain And Immune Systems

Renaud Massart et al from McGill University have recently published an article in Scientific Reports on the effects of chronic pain on the body. “Chronic pain” is pain that has lasted for 6 months or more. The study was performed on rats with induced nerve injuries.

The results showed epigenetic changes in the DNA of the prefrontal cortex and in the DNA of T cells. Their findings support the notion that persistent pain affects multiple biological systems. It’s possible that future research will show changes to other systems as well.

Bright Light Effective for Depression

The use of bright light therapy to treat seasonal affective disorder (SAD) is well documented and evidence based but I had never heard of using light therapy to treat nonseasonal major depressive disorder (MDD). Raymond Lam et al, from the Department of Psychiatry at the University of British Columbia, designed an elegant study comparing the effects of light therapy, drug treatment (Fluoxetine), combination therapy (light plus drug) and sham-placebo in adults with nonseasonal depression. Their study was published this month in JAMA Psychiatry.

Treatments were given daily for 8 weeks (the light therapy consisted of a 30 min early morning exposure to a 10,000-lux fluorescent white light box) and depression ratings were taken at baseline and at the 8-week end point. Interestingly, the drug antidepressant did not perform any better than the placebo. Both the light therapy and combination therapy showed significant clinical benefit. The combination therapy had the most consistent effects.

The news that light therapy is effective for both SAD and nonseasonal depression means that there is now a new way of treating depression that has few if any side effects. For more stubborn cases a combination of light and drugs can be used or maybe even a combination of light and cognitive behavioural therapy (CBT).

Tai Chi And CBT Decrease Inflammation

Poor sleep has been linked to increased inflammation. Inflammation is known to cause or exacerbate musculoskeletal disorders as well as more serious diseases such as heart disease, stroke and cancer. Irwin and his colleagues conducted a randomised controlled trial looking into the effects of cognitive behavioural therapy (CBT) and Tai Chi on the inflammatory markers of subjects with insomnia. The participants were offered 2 hour weekly sessions for 4 months.

CBT was found to reduce systemic inflammation whereas Tai Chi reduced cellular inflammatory responses. Both interventions reduced the expression of genes encoding proinflammatory mediators.

High Cholesterol Linked To Tendon Problems

A group of Australian researchers have conducted a systematic review of literature to find articles that looked at the relationship between fat levels in blood and tendon pathology and/or pain. Their results were published in the British Journal of Sports Medicine. They found that people with altered tendon structure or tendon pain had significantly higher total cholesterol, low-density lipoprotein cholesterol (“bad cholesterol”) and triglycerides, as well as lower high-density lipoprotein cholesterol (“good cholesterol”).

The researchers conclude that although a relationship exists between an individual’s lipid profile and tendon health, further longitudinal studies are required to determine whether it is a cause and effect relationship.

Interestingly, the results of the China Study, one of the most comprehensive studies of nutrition ever conducted, found that one of the best predictors of diseases of affluence (heart disease, diabetes, cancer, etc.) was blood cholesterol.

Positive Emotions Improve Health-Related Behaviours

Positive psychological states have been linked to better health and longevity. It’s believed to be partly due to the effect of positive emotions and moods on behaviour. Nancy Sin and her colleagues from the university of Penn State evaluated 5-year associations between positive affect and health behaviours in patients with coronary heart disease.

At baseline, they found that subjects with higher positive emotions and moods tended to have better health behaviours such as: physical activity, sleep quality, non-smoking and medication compliance. However, the baseline measurements of positive affect were not predictive of health behaviours at follow-up. Instead, it was increases in positive affect over the 5 years that were linked to improved physical activity, sleep quality and medication compliance.

The authors conclude that “efforts to sustain or enhance positive affect may be promising for promoting better health behaviours”. Although this may be easier said than done, positive psychology does offer methods and techniques to help achieve this aim.