Type: Process Essays
Sample donated: Dorothy Kim
Last updated: October 3, 2019
My undergraduate degree is Biomedical Science BSc (Honours) so therefore my project title is the effects of Roux-en-Y bariatric surgery on small intestinal proteomics in obese-diabetic rats. In relation to this title, my literature review will look at the need for this project. This review will cover the comparison and contrast of different types and outcomes of bariatric surgery to justify why Roux-en-Y was picked. The other titles include the proteomics before and after the surgery and the comparison between the animal and human models.The need for a cure to type 2 diabetes is greater than ever as the rate of obesity has increased in almost all countries and this is a big factor in the development of type 2 diabetes. The treatment of obesity usually encapsulates lifestyle factors like diet and exercise.
The focus on type 2 diabetes is usually management with drugs like metformin and following a low sugar diet however it can also be managed with insulin. In terms of curing type 2 diabetes, there is no other known treatment in those who are grossly obese other than bariatric surgery. The most commonly used technique is called Roux-en-Y (RY) bypass where the small intestine is rerouted directly into the ileum. This technique reduces the size of the stomach which aids weight loss and helps towards curing type 2 diabetes (Flatt, 2007).
However, the loss of the type 2 diabetes happens much faster than expected. In a study undertaken 2 years after bariatric surgery, the amount of weight loss was connected to the incidence of diabetes in the subjects. The study discovered that the levels of type 2 diabetes were higher in those who had not lost weight than who had with levels as low as 0.0-0.5% in those who had major weight loss (Sjöholm et al, 2015).
Bariatric surgery is even recommended as a treatment by the National Institute of Clinical Excellence. The issue is the cost of the surgery and the fact that it does not affect all those who undergo the surgery the same way, therefore studies using animal models are now being used to discover why the surgery works. There is a need to understand this as while the incidence of type 2 diabetes increases, the need for a cure increases and the budget decreases leading research to discover what makes it work so well and if there is a cheaper alternative. Research has shown GLP 1 levels increase while GIP concentrations decrease (Flatt et al, 2009).
The research we plan to undertake will try to detect differences in the peptides produced by rats undergoing sham and bariatric surgery. This is important, as knowing the peptides could be the next step in formulating an injectable form to cure type 2 diabetes which would cost less, be less invasive than surgery and be more accessible. This could lower mortality rates and reduce the economic impact of type 2 diabetes and its side effects of improper management.Main Body Comparison and Contrast of Different Types and Outcomes of Bariatric Surgery There are several types of bariatric surgery such as vertical sleeve gastrectomy and Roux en Y Gastric bypass. The method chosen was Roux en Y Gastric bypass and there are several reasons why. In a study by Abegg et al (2015), the effects both were compared on 18-week-old Zucker rats. The results found that the short-term effects of the surgeries were similar but that the differences became more apparent in the long term. The rats at 70 days post-operative that had undergone SG had higher rates of increased food intake, weight regain and higher insulin requirements to maintain blood glucose below 15mmol/L.
However, the issue with Roux en Y is that several rats underwent severe hypoglycaemia which means the long-term benefits come at the expense of a higher risk of hypoglycaemia. The results of this study can be used to say that SG is unsuitable as the benefits are mainly short-term. If the results are the same in humans, which further study is necessary to conclude, vertical sleeve gastrectomy is not financially sound as the surgery is costly making Roux en Y a better option.
These can also be compared to biliopancreatic diversion/duodenal switch which has a higher resolution and improvement at 95.1% however is not as widely used as Buchwald et al (2009) found upon reviewing that it had a mortality rate of 1.1% in 3030 patients compared to 0.5% in 5644 patients undergoing gastric bypass like Roux en Y Gastric bypass. This makes gastric bypass a better and safer option as a review found that weight and diabetes resolution was second best in gastric bypass after biliopancreatic diversion/duodenal switch. In the same review of 135,246 patients, gastric band surgery was worst for weight and diabetes resolution (Buchwald et al, 2009). In a 2004 study investigating the connection between weight loss and mortality, there were two types of surgery used- Roux en Y Gastric Bypass and vertical banded gastroplasty (VBG). The study shows a comparison between the two although VBG was not carried out at as high a frequency.
1035 patients underwent bariatric surgery with 81.4% experiencing a Roux en Y gastric bypass, when open and laroscopic are combined, and 18.7% having VBG. Of these patients undergoing VBG, 35% were then converted to an open Roux en Y mostly due to outlet obstruction (58%) and lack of weight loss (33%). This suggests that a Roux en Y gastric bypass is a better option to offer first as conversion adds cost and the patients who had a gastric bypass lost more percent initial excess weight (68.
7% +/- 23 for open RY gastric bypass), than those who had VBG (57.3% +/- 24.8) (Christou et al, 2004). However, this study is not a direct comparison to the other ones as the participants had no other health conditions beforehand and the data is taken from a paper that did not set out to compare the two types. Even so, the data is still relevant as it shows a decent comparison between the two and specifically highlights the need for conversion from VBG to RY gastric bypass which is useful for showing the efficacy of VBG which is now being performed infrequently The justification for the choice also comes from the popularity of the surgery where 39.7% of 344,221 bariatric surgery patients underwent Roux en Y in a study in 2008. In popularity, it comes second to adjustable gastric banding which does not have the same level of benefits.
These results are just an average and the true numbers paint a different picture. For example, the popularity in Europe increased from 11.1 to 39.0% while it decreased in the USA and Canada from 85.0 to 51.0%. (Buchwald and Oien, 2009).
The popularity is important because it can also give an idea about the experience and knowledge of the surgeons as recommending a difficult or less used surgery may result in a lower uptake and decreased quality in patient care. This study is based on self-reported data from national groupings which means the results may be slightly inaccurate as it is not based on raw data. Bariatric Surgery as a PreventionOnce the idea of bariatric surgery being used as a treatment for morbidly obese people with diabetes reached prevalence, there was a natural progression to study using it as a prevention instead of a cure. A study that invited this was based on a simple principle of asking whether intentional weight loss influenced diabetes associated mortality. The answer was that it possibly did as among the men who had prior health conditions and lost less than 20 pounds, the mortality rate decreased 32% (Williamson et al, 1999) and decreased by 30-40% in the previously tested women who had prior health conditions (Williamson et al, 1995). This suggested that there was a link between weight loss and decrease in diabetes associated mortality with the preliminary studies being based on a survey conducted from 1959-1960.
A follow up study was conducted to investigate this link which looked at data collected between 1959 and 1972 from 4,970 overweight individuals with diabetes aged between 40 and 64 years. The results showed a 28% decrease in diabetes associated mortality, in the 34% of people who intentionally lost weight, with best results shown when 20-29 pounds was lost and an unexplained slight increase in total mortality when over 70 pounds was lost (Williamson et al, 2000). This has since progressed to using bariatric surgery as losing weight is a difficult process. In a study, the use of bariatric surgery meant that the group had a mortality rate of 0.68% compared to the control group which had a rate of 6.
17% with one of the most marked decreases being under endocrinological conditions such as T2DM. This study was undertaken on 1035 people in the treatment group and 5746 in the control group with all the participants having no prior medical conditions apart from morbid obesity. The control group was age and gender matched (Christou et al, 2004).This has been further confirmed by a study that found the mortality rate for diabetes decreased by 92% in the surgical group however strangely, the death rate not caused by disease was 1.38 times higher