Duodenal Mucosal Resurfacing for Treatment of Type 2 Diabetes?

Our knowledge and understanding about the role of gut hormones in type 2 diabetes continues to grow, as we get a better understanding of the mechanisms involved in the often dramatic improvement in diabetes that is seen after bariatric surgery.  In gastric bypass surgery, we know that at least one of the mechanisms involved is food literally bypassing the first segment of the small intestine, called the duodenum.  This effect may be seen because food is more rapidly delivered to the intestine further down, causing a more powerful release of hormones from the more distal intestine (called the hindgut hypothesis).  However, there may also be an as yet unidentified hormone (or hormones) secreted by the first part of the gut that have an antidiabetic effect, and by having food skip over this part of the gut, this mystery antidiabetic hormone is not released, thereby improving blood sugar control (called the foregut hypothesis).  We do know that the surface of the duodenum in a person with diabetes is altered, with a sort of overgrowth of cells in the duodenal mucosal (called hypertrophy and hyperplasia).

For believers of the foregut hypothesis, a novel approach called Duodenal Mucosal Resurfacing (DMR) is now being studied to see if diabetes control can be improved by doing a sort of 'thinning out' of the lining of the upper part of the intestine.

The first human study of DMR, recently published in the journal Diabetes Care, performed the DMR procedure in 39 patients with type 2 diabetes.  They found an improvement in diabetes control at 6 months post procedure, with greater improvement in those who had a longer segment of the duodenum ablated than those that had a shorter segment treated. Improvement in blood sugars was seen as soon as 1-2 weeks after the procedure, despite no restrictions in diet or calorie intake being recommended.  The improvement in diabetes control was not as powerful as what is seen with gastric bypass surgery, suggesting that there are many additional elements at work in gastric bypass surgery.  The authors also noted that there was some erosion of the improvement in diabetes control at 6 months, so certainly larger and longer studies need to be done to understand what the effect of this procedure is over the long term. There was little weight loss in this study (only a few kg), so the DMR does not hold promise as a weight management strategy.   The procedure was well tolerated overall, though there were three cases of duodenal stenosis that were treated with balloon dilatation.  The authors noted no signals for malabsorption (eg no calcium abnormalities or iron deficiency anemia), but this would need to be evaluated carefully in long term studies as well.

It will be interesting to see further study of the DMR procedure.

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www.drsue.ca © 2016

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Do Electric Assist Bikes Count As Exercise?

While highly frowned upon when snuck into the Tour de France (are you kidding me?!), electric bikes can be a very useful piece of equipment to zip around town.  These are bicycles that are equipped with electrical assistance, which is activated only when the rider is actively pedalling.  You may wonder – does using these bikes still count as exercise?  A recent study tells us – yes!

The study, published in the European Journal of Applied Physiology, enrolled 20 people who led sedentary lifestyles, and evaluated several measures of health after 4 weeks of using the electrically assisted bike for at least 40 minutes, three days per week. 

They found that using the ‘pedelec’ bikes provided a moderate level of exertion, similar to walking (4.9 METs on average).  After just 4 weeks, there was an improvement in their glucose tolerance, and an increase in their power output and VO2max (a measure of maximal aerobic capacity).    Participants also found the bikes to be fun, to the point where over half of participants ended up cycling over 50% more than the required amount.

So, while using a regular bicycle would provide more exercise, a pedelec bike is a great option for people who have knee problems, struggle to get uphill on a bike, or if you want to get further in a day than you otherwise would on a regular bike.  (We used them on a trip Kyoto last year so we could make it to all the far flung temples we wanted to see – fantastic!)    Pedelecs remove the potential deterrents of cycling such as longer distances or hills, and they can be incorporated into daily life as a means of transport when the weather/climate permits (rather than having to find specific extra time in the day to exercise).  

Follow me on twitter! @drsuepedersen

www.drsue.ca © 2016

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Does Losing Weight Improve Fertility in Polycystic Ovary Syndrome?

Polycystic ovary syndrome (PCOS) is a very common cause of infertility.  Women with PCOS often have infrequent periods, decreased or absent ovulation, and can also have unwanted hair growth (eg to face or abdomen) and/or acne.  The underlying problem is that of insulin resistance, which (long story short) causes the ovaries to overproduce testosterone.  While about half of women with PCOS have a normal and appropriate body weight, the other half have overweight or obesity; also, we know that PCOS gets worse with weight gain and better with weight loss (in those who carry excess weight).

So, a natural question to ask is whether weight loss could improve fertility in women with PCOS and overweight or obesity.

A study was recently published to answer this question.  In the study, which was a post hoc analysis of two concurrently run randomized clinical trials, four approaches were compared in women with PCOS, infertility, and overweight or obesity:

• immediate treatment with clomiphene
• birth control pill for 4 months followed by clomiphene
• lifestyle treatment and antiobesity medication for weight loss for 4 months, followed by clomiphene
• birth control pill and lifestyle treatment and antiobesity medication for weight loss for 4 months, followed by clomiphene

They found that women who were treated with clomiphene without weight loss treatment had an ovulation rate of 45%, and a birth rate of 10.2%.  These numbers were nearly identical in the women who were on the birth control pill for 4 months before getting clomiphene.

In contrast, women who had lifestyle/antiobesity medication (with or without the birth control pill) had a higher rate of ovulation (63%) and a higher birth rate of 25%.  They lost an average of 6.5% body weight in the four month treatment period before receiving clomiphene.

For a woman with PCOS and infertility who carries excess body weight, these finding could present a dilemma: does one go ahead with fertility treatment and hope for the best, or is it better to try to lose weight first, before embarking on fertility treatments?  Women are more likely to start thinking about getting pregnant well into their 30s in this day and age, so there may be a palpable time pressure against taking the time to try to lose weight first.  An important point to consider is that not only does weight loss improve fertility (as per this trial), but it also decreases the risk of the future child developing obesity and type 2 diabetes.  In addition, going into pregnancy with a healthier weight and carrying a healthier weight in pregnancy also decreases the risk of many complications of pregnancy, including gestational diabetes, pregnancy induced hypertension, and babies born large for gestational age (which carries a host of risks and potential complications).

Finally - a note that antiobesity medications must be stopped before attempts to become pregnant, as there is no safety data on these medications in conception/pregnancy.

Follow me on twitter! @drsuepedersen

www.drsue.ca © 2016

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