Introduction My undergraduate degree is Biomedical Science BSc (Honours)

Introduction

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.

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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 Prevention

Once 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 1.58 times higher than in the control group.Bibliography

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Corteville, C., Docherty, N., Boza, C., Lutz, T., Muñoz, R. and le Roux, C.
(2015). Effect of bariatric surgery combined with medical therapy versus
intensive medical therapy or calorie restriction and weight loss on glycemic
control in Zucker diabetic fatty rats. American Journal of
Physiology-Regulatory, Integrative and Comparative Physiology, 308(4),
pp.R321-R329.

Buchwald, H.,
Avidor, Y. and Braunwald, E. (2005). Bariatric Surgery: A Systematic Review and
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Buchwald, H.,
Estok, R., Fahrbach, K., Banel, D., Jensen, M., Pories, W., Bantle, J. and
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