We have known for a long time that there are close links between depression, aging and heart disease, but the nature of the link has remained elusive. Most of the smart money has been on inflammation, but there could be other candidates.

New research in the journal Brain, Behavior and Immunity has linked an increase in two inflammatory proteins in the immune system with a latent viral infection and proposes a chain of events that might accelerate cardiovascular disease. It is possible that the same process may be involved in a number of other ailments that can afflict us, as we get older. The findings also suggest that chronic depression may play a key role in initiating the cascade that can lead to the development of coronary artery disease.

It has been known for some time that increased levels of the proinflammatory cytokines, TNF-α and IL-6, predict mortality and morbidity. High levels of each of them are found in the plasma and in atherosclerotic lesions of people with cardiovascular disease.

The levels of IL-6 in the body increase as the immune system ages. Some of the IL-6 is generated by immune cells - macrophages - that go to the site of an infection or injury. Earlier work by the team also showed that increases in psychological stress and depression could substantially raise the levels of IL-6 and TNF-α in the body.

Increased stress and depression can also trigger latent viruses to reactivate and begin reproducing inside cells. The viruses of greatest interest are some herpes viruses such as the Epstein-Barr virus (EBV). We know that up to 90% of the people in North America have been infected by EBV by the time they are adults.

If EBV begins to multiply in cells in the body, it produces a protein called dUTpase that, in turn, can stimulate macrophages to make yet more IL-6.

The researchers developed a model to test these linkages by using endothelial cells that line the inside of veins in umbilical cord tissue. I spent years working with these cells myself, and they provide an excellent substrate for examining vascular responses and the interaction between blood vessels and macrophages when exposed to the virus as well as the dUTpase protein.

As expected, the production of IL-6, as well as TNF-a, were increased just as they would be as part of the inflammatory process in the body. Such chronic incidents of inflammation are integral to the onset of atherosclerosis and an array of other diseases.

This work suggests a new way of thinking about how vascular diseases develop. We carry around these latent herpes viruses in our bodies virtually all our lives and periodically they can hurt us as we age, develop depression or, perhaps a nutritional imbalance.

Taken together with the recent data on the physical effects of loneliness, if you want to live a long and healthy life:

• Watch you mood: depression can kill you
• Stay socially engaged: loneliness can be fatal
• Maintain a balanced diet
• Take some physical exercise every day
• Learn – and practice! – some simple stress management techniques. You can obtain some at RichardGPettyMD.com

I have the dubious distinction of living in a part of the United States with one of the highest rates of methamphetamine abuse in the country. Around here most of the first time users are teenage girls who are trying to lose weight.

In the last few years the spread of methamphetamine abuse across the United States has been as rapid as it has been alarming. Until about six years ago, methamphetamine use was seen mostly in the western and rural United States. Then it jumped over the Mississippi and continued its demonic march to the sea and Georgia has been hit like a ton of bricks.

Not only can crystal met ravage the brains of users, they can get a wide range of physical problems including inflammatory and immune problems throughout the body.

Methamphetamine abuse has now expanded rapidly throughout the rest of the country and across different ethnic groups. According to the 2005 National Survey on Drug Use and Health it is estimated that 10.4 million Americans ages 12 or older have used methamphetamine at least once in their lifetimes for non-medical reasons.

There is a new and important study from the Scripps Institute that has shown that long-term methamphetamine use changes circulating proteins in drug users, causing aberrant immune responses. As a result, increased levels of pro-inflammatory cytokines - proteins that are involved in immune responses - may initiate a previously unrecognized molecular mechanism for the development of cardiovascular disorders including vasculitis, an inflammation of the blood vessels.

It appears that methamphetamine can add sugars (a.k.a. “glycate”) proteins. The researchers found that the immune system responds dramatically to this methamphetamine-induced glycation, which may lead to vascular inflammation. There was a direct relationship between methamphetamine intake and the level of circulating antibodies in animal models. This immune response, coupled with antibodies binding to methamphetamine, might make the drug less biologically available leading to an increased need for higher and higher doses, a problem found among chronic methamphetamine users.

The resulting glycated proteins are called advanced glycation end products (AGEs) that modify the function of proteins and are associated with a number of diseases including diabetes and Alzheimer’s disease.

Methamphetamine-AGE proteins not only increased antibody production, but also were strong enough to overcome the drug’s natural immunosuppressive qualities. Furthermore, a wide range of cytokines directly linked to AGE exposure were increased in rats that self-administered methamphetamine.

The study also showed that even limited daily access to the drug was enough to produce an over-expression of vascular endothelial growth factor which is a potent signaling cytokine involved in angiogenesis and vasodilatation.

If you know anyone tempted to dice with this vile toxin, ask them to have a look here.

The amount of sleep a person gets affects his or her physical health, emotional well-being, mental abilities, productivity and performance. Recent studies associate lack of sleep with serious health problems such as an increased risk of depression, obesity, cardiovascular disease and diabetes.

There was some interesting research presented at SLEEP 2007, the 21st Annual Meeting of the Associated Professional Sleep Societies in Minneapolis in the middle of June.

One study that caught my eye was conducted by Siobhan Banks of the University of Pennsylvania School of Medicine. The research was based on preliminary analysis of 39 subjects, each of whom participated in a laboratory-controlled chronic sleep restriction protocol. The subjects underwent two nights of baseline sleep followed by five hours of sleep restriction. The results showed a statistically significant decrease in the heart rate variability after just five nights of sleep restriction.

We already know that a reduction in heart rate variability may occur in several cardiological and non-cardiological diseases, and it is usually a harbinger of a poor outcome.

This work may provide the mechanism for why short sleep duration is associated with a heightened risk of heart and other circulatory problems.

The amount of sleep a person gets affects his or her physical health, emotional well-being, mental abilities, productivity and performance. Recent studies associate lack of sleep with serious health problems such as an increased risk of depression, obesity, cardiovascular disease and diabetes.

So if confirmed, the take home message is that sleep deprivation has a negative effect on a person’s cardiac activity and that may in turn increase the risk of cardiovascular disease and mortality.

A chance discovery at the University of Leeds in the United Kingdom may give credence to longstanding claims by chiropractors that treating pain and stiffness by adjusting the neck can also lower blood pressure.

In a study published in the Journal of Neuroscience Jim Deuchars and his team report finding connections between rats’ neck muscles and a specific region of the brain. Their findings indicate that the neck muscles could play a key role in controlling blood pressure, heart rate and respiration.

They found that nerves run from receptors in the neck muscles to a region in the brainstem called the nucleus tractus solitarius that is known to be involved in the control of autonomic nervous system. It seems likely that signals from the neck could play a key role in ensuring an adequate supply of blood to the brain as we change position, for instance standing up suddenly. If the signaling system fails we may run into problems with low blood pressure (postural hypotension) and difficulties with balance.

Although it is early days, and it is a long way from a rat study to understanding human physiology, the finding may do more than provide a tentative explanation for the chiropractic reports. It may also explain another puzzle: why some people with whiplash injuries get trouble with their blood pressure. On the other hand, there have been a number of studies that have shown that the practice of yoga may help control blood pressure. It had been assumed that it was simply a consequence of generalized relaxation, but perhaps it is more specific than that: could a soft flexible neck be important in maintaining a healthy blood pressure?

The best research studies are the ones that suggest more questions than answers: on that criterion this is a most important study.

I have spent so much time talking about insulin resistance becuase it is one of the greatest medical threats facing the world.

It is estimated that approximately 33% of the adult population of the United States is insulin resistant, and if left untreated many will develop diabetes, hypertension and an array of other problems. It is an epidemic that is expected to swamp most health care systems around the world, yet sadly it may in most cases be preventable.

There is an enormous literature on insulin resistance. As of this afternoon there are almost 33,000 scientific papers on the subject.

I created this graphic to try and summarize the key points about insulin resistance: the main factors that may cause it, as well as the most important medical consequences.

(Click on the graphic to expand it.)

The Main Causes of Insulin Resistance are:

• Aging
• Intra-abdominal obesity
• Inactivity
• Glucose intolerance
• Genetics
• Fetal malnutrition
• Cigarette smoking
• Some medications

The Main Consequences of Insulin Resistance are:

• Type 2 diabetes mellitus
• Hypertension
• Arteriosclerosis
• Polycystic ovarian syndrome
• Non alcoholic fatty liver disease
• Disturbances in the function of the vascular endothelium
• Elevations of triglycerides and cholesterol
• Disturbances of clotting
• Disturnaces in kidney function
• DIsturbances in one type of heart rhythm
• Elevated uric acide levels
• Some malignancies

This is probably not a complete list, but it gives you a very good idea of the reasons for looking for insulin resistance. Many - but not all - experts now recommend measuring insulin resistance in people at high risk of developing any of these medical problems.

We have good evidence that lifestyle changes can prevent the development of many of these dire consequences, so it is certainly something worth discussing with your health care provider.