As a nephrologist, I come from a field in which many key decisions are based on the outcome of a biopsy specimen. There are indeed many areas of medicine in which tissue biopsies are routinely used to establish a diagnosis or to guide treatment. Could the same hold true for obesity?

We have long known that obesity is by no means a homogeneous condition and that the clinical manifestation of obesity related comorbidities covers a wide and unpredictable spectrum of disorders. It is thus only likely that different forms of obesity are heterogeneous at the tissue level and in their response to treatment.

A first indication of just how adipose tissue biopsies may be used in clinical practice now comes from a study published in this month’s issue of the International Journal of Obesity. In this paper, Wang and colleagues from the Pennington Biomedical Research Center, Baton Rouge, LA, USA, use microarray gene expression technology to group 72 otherwise healthy obese men and women into two distinct clusters (denoted red and green). Interestingly, the red cluster contained no men, had “red” patients had less visceral fat and smaller fat cells. More importantly, it appeared that the patients in the green cluster appeared to respond with slightly greater weight loss to adrenergic treatment with ephedra and caffeine (not exactly my choice of antiobesity drugs) in an 8 week intervention.

Although the authors may be a tad overenthusiastic in terms of proclaiming that this paper now “brings us into an era of personalized treatment in the obesity clinic”, there is certainly some hope that fat biopsies may someday prove to provide a clinically useful predictor for response to specific treatments.

Obviously much needs to happen before anyone would seriously consider routine fat biopsies in clinical practice. For one, we would need prospective studies on sensitivity and specificity to detect clinically significant differences in response. Obviously, cost-effectiveness analyses would also need to establish the cost/benefit ratio for what is still a very expensive technology.

For now, nonetheless, the study confirms what I have maintained all along - obesity is a heterogeneous disorder and there is no reason to assume that any one treatment will work for all.

AMS
Edmonton, Alberta

Curcumin is the principle ingredient of tumeric or “haldi” as it is called in Hindi. This is the spice that gives Indian curries their bright yellow color. The tumeric root (a relative of ginger) has long been thought to have all kinds of medicinal properties, and growing up in India, I remember my mother treating boils and abscesses on our household pets with tumeric paste. Curcumin is supposed to not only have antibiotic, antiinflammatory, antiarthritic, antioxidant and anticancer properties, regular consumption is also alleged to increase brain power.

Now, a study by Asma Ejaz and colleagues from Tufts University, Boston, MA, USA, just published in the Journal of Nutrition, suggests that curcumin may also reduce fat formation by blocking the angiogenesis (growth of new blood vessels) necessary for the expansion of adipose tissue and by positively changing fat cell metabolism.

The researchers studied the effect of curcumin both on cultured 3T3-L1 adipocytes as well as in mice fed a high-fat diet.

In cell culture studies, curcumin supressed preadipocyte differentiation, promoted adipocyte apoptosis (programmed cell death) and inhibited growth of adipokine-stimulated angiogenesis.

Consistent with these findings, in the high-fat fed mice, over 12 weeks, curcumin did not affect food intake but reduced body weight gain, adiposity, and microvessel density in adipose tissue. Curcumin also increased expression of key enzymes involved in fat oxidation. Blood cholesterol levels were also lowered by curcumin treatment.

Leaping from mouse to man, the authors speculate that dietary curcumin may not only help prevent obesity but may also have favourable effects on fat metabolism.

How much of an impact this finding may have on the obesity epidemic remains to be seen - clearly, eating a daily dose of curry (as most Indians do) is not a sure bet when it comes to preventing obesity as evidenced by the burgeoning obesity epidemic in India (but who knows, perhaps the Indian obesity epidemic would be far worse without the curry?)

In any case, I am certainly happy for any excuse to stop by my favourite Indian restaurants.

AMS
Edmonton, Alberta

Last week saw an almost complete edition of the New England Journal of Medicine devoted to obesity - the key finding: brown adipose tissue (BAT) is alive and well in adults and in some people may contribute significantly to resting metabolic rate.

Without going into details on the findings (as these have been widely described in numerous media articles and TV reports) here is what’s new:

Although the discussion has been going on for a long time, these articles now provide conclusive evidence that BAT is indeed present in adults - women have more than men.

The presence of BAT is negatively correlated with BMI - the higher the BMI, the lesser the BAT. This suggests that having BAT may protect from weight gain (are these the folks, who can eat all they want without gaining a pound?).

BAT is stimulated by exposure to cold - not entirely unexpected. I can’t wait to see how this concept is embraced by the weight loss industry and public media.

BAT is less present in older individuals - again, not unexpected, given that expression of BAT is linked to sympathetic nervous activity, which tends to decrease with age.

Obviously, lots of interesting questions:

Can pharmacological stimulation of BAT promote weight loss - remember, this was already tried unsuccessfully with beta 3-agonists. They stimulated BAT but were poorly tolerated and never made it to market.

Can BAT imaging help identify folks at risk for weight gain - certainly not with current technology (PET-CTs), which would be prohibitively expensive.

Is turning down the ambient temperature an effective solution to preventing obesity - my guess is not.

Great science - unfortunately, no quick fix for the obesity epidemic.

AMS
Edmonton, Alberta