Why Inflammation Is a Hot Topic You know what inflammation looks like: You get a cut or bruise, and the area around it soon turns red, gets warm, and swells up. This is called the acute inflammatory response, and it’s your immune system’s defensive reaction to infection or injury. A complex array of immune cells congregate at the site and release a variety of chemicals to deal with the infectious organisms or debris from the injury and to allow tissue repair to begin; normally the inflammation gradually subsides. This immune response is essential to life. But there’s another way inflammation works—it can be chronic and cause a low-grade systemic reaction. Because it increases with aging, it has been dubbed “inflammaging.” Chronic systemic inflammation has been the focus of a great deal of scientific attention during the past two decades (especially the past few years) and is now viewed as a sort of “unified field” explanation for many, if not most, age-related chronic diseases. Accordingly, factors (genetic, lifestyle, and environmental) that promote chronic inflammation or disrupt the body’s protective mechanisms against it may increase the risk of premature aging and the disorders that go with it. On the other hand, healthy aging and longevity may be related to reduced levels of inflammation and/or strong protective mechanisms that guard against its adverse effects. This was suggested by the results of a study in the Canadian Medical Association Journal last year, which included 3,000 British civil servants. It found a strong link between higher levels of chronic inflammation (as measured by blood levels of an inflammatory marker) and a decreased likelihood of “successful aging,” defined as optimal physical and cognitive health and the absence of chronic diseases. In fact, elevated levels of inflammation appeared to reduce the odds of successful aging by half over the next decade and to markedly increase the odds of cardiovascular disease and death. Many complex roles Researchers have found that chronic inflammation is involved, to varying extents, in everything from coronary artery disease, cancer, obesity, and type 2 diabetes to Alzheimer’s, chronic obstructive pulmonary disease (COPD), allergic conditions such as asthma, and autoimmune conditions such as rheumatoid arthritis and inflammatory bowel disease. But how exactly is inflammation involved? Does it cause chronic diseases, result from them, or simply accompany them (perhaps because the factors that contribute to the diseases also increase inflammation)? Inflammation appears to play all these roles. It can be both a cause and an effect of some disorders—setting up a vicious cycle that helps explain their chronic nature. For example, chronic inflammation plays reciprocal roles with obesity and insulin resistance. It contributes to the development of insulin resistance, which in turn may help promote obesity. Conversely, obesity worsens insulin resistance and increases chronic inflammation, partly because body fat (especially the type surrounding internal organs) releases pro-inflammatory compounds. In effect, inflammation, obesity, and insulin resistance reinforce one another, often resulting in type 2 diabetes. What’s more, many lifestyle factors that promote inflammation, such as being sedentary and having an unhealthy diet, also promote obesity and insulin resistance. A relatively new theory about chronic inflammation involves the human microflora—the trillions of bacteria and other organisms living in the colon, on the skin, and elsewhere in the body. Changes in the microflora caused by lifestyle and environmental factors (such as diet, antibiotic use, and air pollution) may play a role in the increase in inflammatory diseases in the industrialized world. Hard to pin down Chronic inflammation is a varied phenomenon that affects nearly every aspect of human physiology and disease development. Many different kinds of specialized cells and chemicals are involved in producing and regulating these inflammatory processes. Since it is so complex, there is no way to measure chronic inflammation directly. Instead, researchers measure a variety of inflammatory chemical markers in the blood or tissue, notably interleukin-6, tumor necrosis factor (TNF), C-reactive protein (CRP, see inset), prostaglandins, and leukotrienes. Elevated levels of these factors are good indicators of disease activity for some conditions (such as inflammatory bowel disease). But it’s not clear whether measuring them adequately gauges inflammation and the resulting risks for some other disorders (such as cancer).
Posted on: Tue, 18 Nov 2014 16:24:54 +0000
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