Hindawi Publishing Corporation
Journal of Obesity
Volume 2013, Article ID 839275, 11 pages
Bariatric Surgery as Potential Treatment for NonalcoholicFatty
LiverDisease: A FutureTreatment byChoiceor byChance?
ShujaHafeez1and MohamedH. Ahmed2
1Department of Emergency Medicine, e James Cook University Hospital, Middlesbrough TS4 3BW, UK
2Department of Medicine, Wexham Park Hospital, Slough, Berkshire SL2 4HL, UK
Correspondence should be addressed to Mohamed H. Ahmed; email@example.com
Received 1 November 2012; Accepted 20 December 2012
Academic Editor: Ahmed Almobarak
Copyright © 2013 S. Hafeez and M. H. Ahmed.isisanopenaccessarticledistributedundertheCreativeCommonsAttribution
License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly
Morbid obesity is strongly associated with nonalcoholic fatty liver disease (NAFLD) which is one of the most common causes of
chronic liver disease worldwide. e current best treatment of NAFLD and NASH is weight reduction through life style modi-
�cations, antiobesity medication, and bariatric surgery. Importantly, bariatric surgery is the best alternative option for weight
treatment option for individuals who are grossly obese and associated with marked decrease in obesity-related morbidity and
mortality. e most common performed bariatric surgery is Roux-en-Y gastric bypass (RYGB). e current evidence suggests that
bariatric surgery in these patients will decrease the grade of steatosis, hepatic in�ammation, and �brosis. NAFLD per se is not an
indication for bariatric surgery. Further research is urgently needed to determine (i) the bene�t of bariatric surgery in NAFLD
patients at high risk of developing liver cirrhosis (ii) the role of bariatric surgery in modulation of complications of NAFLD like
diabetes and cardiovascular disease. e outcomes of the future research will determine whether bariatric surgery will be one of
the recommended choice for treatment of the most progressive type of NAFLD.
Nonalcoholic fatty liver disease (NAFLD) is an increasingly
recognised condition that occurs in all age groups and
ethnicities . Although �rst recognised in the 1930s ,
acknowledged clinically in the 1950s , and characterised
histopathologically in the 1980s , only recently has the
growing burden of disease gained notoriety . Over this
time, an assortment of terms has been used to represent
this curiosity, including fatty liver hepatitis, nonalcoholic
Laennec’s disease, diabetes hepatitis, alcohol-like liver dis-
ease, steatonecrosis, and nonalcoholic steatohepatitis [6, 7].
spectrum of hepatic conditions, which vary histologically.
At one end of the spectrum lies simple steatosis, a relatively
benign condition , in which there is an accumulation of
lipids within the hepatocytes >5% of liver weight . At the
other end is nonalcoholic steatohepatitis (NASH), which is
changes ; this subset of patients is at increased risk of fur-
carcinoma , and terminal liver failure .
e diagnosis of NAFLD is oen made fortuitously;
steatosis and NASH are clinically indistinguishable  and
in the absence of hepatic decompensation, largely asymp-
tomatic . Some patients may complain of malaise or
right upper quadrant pain, with hepatomegaly being the
only clinical observation . ose at the malign end of
the NAFLD spectrum may demonstrate evidence of cirrho-
sis, bruising, varices, ascites, splenomegaly, jaundice, and
encephalopathy . Identi�cation of patients before they
reach this point is therefore important, to avoid liver-related
morbidity and mortality. A high index of clinical suspicion
is needed to diagnose NAFLD, particularly in those whose
serum liver function tests reveal an elevated ALT .
Meticulous history taking and investigation is also needed
to exclude excess alcoholism (>10g ethanol per day ) and
other causes of liver disease or steatosis, viral, nutritional,
2 Journal of Obesity
drug/environmental/toxin induced, metabolic, genetically
inherited, bowel diseases, and endocrine [6, 17–19].
Noninvasive imaging techniques such as ultrasound
(US), magnetic resonance imaging (MRI), and computed
tomography (CT) can be employed to further investigate the
liver, as all are able to detect NAFLD . However, negative
imaging studies do not rule out NAFLD . Furthermore,
these imaging techniques are unable to differentiate between
simple benign steatosis, NASH, and the degree of �brosis
liver biopsy remains the gold standard for the con�rmation
and staging of NAFLD , but it is not without its risks
, and the decision to proceed with biopsy must be
individualised and involves the advantage and disadvantages
of biopsy. NAFLD is not a condition that occurs in isolation.
It is now known to have strong associations with insulin
resistance , diabetes mellitus , dyslipidaemia ,
hypertension , and central obesity , all of which are
components of the metabolic syndrome. In light of these
associations, NAFLD is oen regarded as the hepatic mani-
festation of the metabolic syndrome [13, 42].
Indeed the prevalence of NAFLD continues to grow 
and appears to mirror the rising trends in obesity and type
2 diabetes in those subscribing to an increasingly sedentary
lifestyle . In the adult population, NAFLD is thought to
rises to up to 74% . is trend is also mirrored in the
children population; up to 2.6% of the general population
 and up to 52.8% of obese children  have NAFLD.
Approximately 5% of those with NAFLD will progress to cir-
rhosis with nearly 2% will die from complications stemming
from a cirrhotic liver . Individuals with NAFLD are also
coexistence of metabolic syndrome .
e current mainstays of treatment aim to reduce weight
the metabolic syndrome . Although no drugs are speci�-
cally licensed for the treatment of NAFLD, there is evidence
suchas Orlistat  and drugs thataugment insulin sensitiv-
ity and reduce plasma glucose concentrations and oxidative
amongst those shown to improve liver histology in NAFLD.
conservative measures, such as weight loss through dieting,
exercise, and lifestyle modi�cation, all of which have shown
to improve liver histology in both adults  and children
affect theliver in NAFLD andthiswas thoughttobe due
to de�ciency of macro/micronutrients .
Bariatric surgery has been shown to be superior to con-
servative measures with respect to weight reduction in the
with it . Since obesity is the key cause of NAFLD, this
paper will look at bariatric surgery as a means of treatment
for NAFLD. Worldwide, the number of surgical bariatric
procedures has risen by an estimated 761% over the past ten
years . Procedures can be divided into 3 broad categories
based on their mechanism of action :
(1) restrictive procedures, which aim to restrict the
amount of food that can be eaten by surgically reduc-
ing the size of the stomach. e restrictive proce-
gastroplasty, laparoscopic adjustable gastric banding,
and sleeve gastrectomy;
(2) malabsorptive procedures are less popular than
restrictive procedures as they are more technically
demanding to be performed and patients oen
develop nutritional de�ciencies. Procedures aim to
bypass a segment of the small bowel so that less food
diversion with duodenal pouch);
by bypassing the proximal small bowel—the Roux-
bowel intact and so avoids many of the unwanted
malabsorptive side effects such as diarrhoea and
nutritional de�ciencies. is is the most common
surgical bariatric procedure performed.
�� �otent�a� �ene�t of �ar�atr�� ��r�er� a�
Treatment of NAFLD
ere is a large body of evidence to support the fact that
when performed by skilled surgeons, bariatric surgery is safe
, decreases obesity related disease , and increases life
expectancy . Despite this, at present there is currently a
lack of randomised controlled trials examining the effects of
bariatric surgery on NAFLD; the only available studies are
either retrospective or prospective cohort studies. We have
searched the Medline for studies between 1970 and 2012
that looked at the impact of bariatric surgery on NAFLD.
We have identi�ed twenty-two studies and their �ndings
were reviewed and presented in the subsequent discussion
the pathophysiological changes that take place following
bariatric surgery that potentially contribute towards the
treatment of NAFLD.
2.1. e Roux-en-Y Gastric Bypass. Considerable studies
NAFLD. For instance, twelve studies [20–31] (�ve retrospec-
from 7 to 116 participants and the follow-up period aer
surgery varied from 12 to 32 months, with one study having
an unidenti�able follow-up period . e predominant
�ndings across these studies beside successful weight loss
were a histological improvement in steatosis, in�ammation,
and �brosis following Roux-en-Y gastric bypass. However,
�ve of the studies [20, 22, 23, 26, 28] had reported a few cases
Journal of Obesity3
T 1: Considerable studies showed that RYGB is associated with marked improvement in NAFLD.
Silverman et al., 1995
Clark et al., 2005
Improved steatosis and �brosis
Improved steatosis, �brosis, and in�ammation
Improved metabolic syndrome, steatosis, and
82% improvement in liver steatosis and �brosis
Decreased factors lead to liver �brosis and
Improved histology of NAFLD
Improved histology in 80%
Improved steatosis, �brosis, and in�ammation
Improved steatosis and �brosis
Resolved NASH in 60%
Complete regression of NAFLD in 83%
Resolved �brosis in 50%
Type of study
305 ± 131 days
Mattar et al., 2005
Prospective cohort70 15 ± 9 months
Mottin et al., 2005
Retrospective cohort90 12 months
Klein et al., 2006
Prospective cohort7 12 months
Barker et al., 2006
Csendes et al., 2006
de Almeida et al., 2006 
Furuya et al., 2007
Liu et al., 2007
Moretto et al., 2012
23.5 ± 8.4 months
18.6 ± 8.3 months
T 2: Summary of studies of VBG and their effect on NAFLD.
Vertical band gastroplasty
Ranløv and Hardt 1990
Jaskiewicz et al., 2006
Stratopoulos et al., 2005
Decrease steatosis from 73% to 40%
Improved steatosis and in�ammation
Improved steatosis and NASH
Type of study
18 ± 9.6 months
aer RYGB. is could be attributed to these patients already
having a pre-existing degree of �brosis which subsequently
worsened by the surgical intervention, or due to a lack of
adequate replacement of macro/micronutrients. e earliest
of these studies, conducted by Silverman et al. , found
post-RYGB in 91 of the obese individuals selected for the
study; 83 showed improvement in steatosis, 5 showed no
change, and 3 had increased steatosis. Pre-RYGB biopsies
revealed that 13 participants had perisinusoidal �brosis; this
was eliminated or reduced in all but 2 individuals, who
showed no change in �brosis following RYGB. One study
participant developed new perisinusoidal �brosis within the
patients selected for the study. In all 17 patients the initial
histopathological criteria for NASH were no longer met on
follow-up biopsy. As well as NASH resolution, subjects also
displayed weight loss and an improvement in biochemical
markers of metabolic syndrome, triglycerides, lipoprotein,
and fasting glucose. Fibrosis was found to have worsened in
2 of the 19 patients. In the study by Csendes et al. , RYGB
resulted in weight loss in all 16 of the study participants, all
solitary participant with normal preoperative liver histology
remained normal on follow-up biopsy, 11 had returned to
normal liver histology, 2 showed histological improvement,
1 participant had progressed to �brosis, and 1 participant
who had cirrhosis prior to RYGB continued to have cir-
Moretto et al.  evaluated liver biopsies taken during
RYGB surgery and aer weight loss in 78 morbidly obese
individuals. 35 of the 78 participants had �brosis on �rst
biopsy; aer weight loss only 19 of these were found to have
�brosis. Of the 43 individuals to be �brosis free on initial
biopsy, 5 were found to have developed �brosis on follow-up
that RYGB surgery resolved NASH in all 23 of the 39 patients
whom displayed evidence of NASH on initial biopsy. One
showed worsening of existing �brosis or cirrhosis.
Studies by Clark et al.  and de Almeida et al. 
steatosis, in�ammation, and �brosis in the vast majority of
evidence of worsening histopathology aer RYGB. Similarly,
Weiner  demonstrated that using one of three bariatric
surgical measures (RYGB or adjustable gastric banding and
biliopancreatic diversions with duodenal switch) resulted
in an improvement in all obesity-related comorbidities, as
well as a complete regression of NAFLD in 83% of the
study cohort. He concluded that obesity surgery successfully
4 Journal of Obesity
T 3: Summary of studies of AGB and their effect on NAFLD.
Adjustable gastric banding studies
Type of study Sample size
± 10 months
± 16 months
50 months ±
Dixon et al., 2004
Improved steatosis, in�ammation, and �brosis
Prospective cohort 36
Dixon et al., 2006
Improved steatosis, in�ammation, and �brosis
Prospective cohort 60
Mathurin et al., 2009 
Improved steatosis and signi�cant increase in �brosis
Prospective cohort 381
T 4: Summary of studies of malabsorptive procedure and their effect on NAFLD.
Postoperative increase in �brosis in 40%, a decrease in
27%, and no change in 33%
Type of studySample size Followup
Kral et al., 2004 Prospective cohort 10441 ± 25 months
Keshishian et al., 2005  Signi�cant improvement in steatosis and in�ammation Retrospective cohort 786–36 months
improves hepatic steatosis, in�ammation, and �brosis with
no evidence to suggest worsening.
18 morbidly obese patients, all of whom had some degree of
NAFLD, a mean excess weight loss of 60% was observed as
well as an elimination of steatosis in 84% and an elimination
of �brosis in 75% of patients in the study. Furthermore,
obesity-related comorbidities also improved and there was
no evidence to suggest that RYGB led to worsening hepatic
histology. e study looking at the effects of RYGB on
NAFLD with the smallest cohort of study participants was
conducted by Klein et al. . ey reported that RYGB
surgery normalises the metabolic abnormalities involved in
the pathogenesis of NAFLD and decreases the expression of
in�ammation. Mottin et al.  focused on the changes in
histological hepatic steatosis in 90 morbidly obese patients
when comparing biopsies taken during RYGB and 1 year
aer surgery. ey found that 82% showed improvement
in steatosis with no patient showing a worsening in histol-
ogy—hepatic �brosis was not measured in this study.
Mattar et al.  studied 70 patients who underwent
one of three bariatric surgical weight loss operations; 59%
had RYGB, 9% had adjustable gastric banding, and 33% had
was taken at the point of surgery and a follow-up biopsy was
taken 15 ± 9 months later. ey showed a reduction in the
prevalence of metabolic syndrome from 70% to 14% and an
improvement in liver steatosis, in�ammation, and �brosis,
with in�ammation and �brosis resolving completely in 37%
and 20% of patients, respectively. Interestingly, another
conclusion drawn from this study was that the RYGB group
lost greater excess weight and a greater improvement in the
grade of liver disease when compared to the two restrictive
procedures. No participant in this study showed evidence of
worsening liver histology on follow up biopsy (Table 1).
2.2. Vertical Band Gastroplasty. Of the 4 studies found
looking at the effects of vertical band gastroplasty (VBG) on
NAFLD, the smallest was conducted by Ranlov and Hardt
, consisting of 15 patients in total of which 8 underwent
VBG. Aer one year there was a signi�cant regression of
hepatic steatosis and the occurrence of steatosis had fallen
of �brosis at any point in the study. Jaskiewicz et al.  also
following VGB in the absence of any new �brotic changes.
e earliest of these studies was carried out by Luyckx et
al. in 1998 . Steatosis was found to be markedly reduced
following weight loss; 45% of the 69 participants had normal
hepatic biopsies on followup (versus 13% on initial biopsy)
and the severity of steatosis was also reduced in those in
whom steatosis had persisted. Despite these encouraging
�ndings, an increase in the incidence of hepatocellular
in�ammation was noted on repeat biopsy, from 14% to
26%. In a similar but more recent study, Stratopoulos et al.
 found in their cohort of 51 morbidly obese individuals
undergoing VGB that there was a signi�cant improvement
in steatosis and steatohepatitis aer weight loss following
bariatric surgery. Although an overall decrease in �brosis
was observed on follow-up biopsy, 11.7% had increased
�brosis. Indeed it appears that VGB has fallen out of favour
in recent years; a recent prospective study comparing forms
of restrictive bariatric procedures  found that VGB had a
failure rate of 65%, with 60% of patients eventually requiring
conversion to RYGB (Table 2).
2.3. Adjustable Gastric Banding. Adjustable gastric banding
(AGB) is the second most frequently performed bariatric
surgery worldwide . It has been proven to be more
effective than lifestyle change, pharmacotherapy, low calorie
diets, and behavioural modi�cation in long-term sustainable
weight loss in moderately obese patients . Only three
Journal of Obesity5
studieswereidenti�ed thatexamined theeffects ofthis mode
of bariatric surgery on NAFLD (Table 1).
Dixon et al.  conducted paired liver biopsies on 36
and the second aer weight loss. Initial biopsies revealed
that in�ammation was present in 23 patients and steatosis
in 12. On follow-up biopsy, taken aer 25.6 ± 10 months,
there were improvements in steatosis, in�ammation, and
�brosis, with only 4 patients ful�lling the criteria for NASH.
ere were no reports of any worsening histology. e same
author led a second similar investigation in 2006 , in
which baseline histological examination revealed that 30 out
of 60 morbidly obese individuals had evidence of NASH.
On follow-up biopsy, taken 29.5 ± 10 months aer AGB,
in biochemical markers of liver function.
AGB was one of three interventions used by Mathurin
et al. , the other two being RYGB and biliointestinal
bypass, to study the long-term effects of bariatric surgery on
NAFLD. Although the percentage of patients with steatosis
fell from 37.4% to 16% aer surgery, in�ammation remained
unchanged and a signi�cant increase in �brosis was seen
in 20% of patients. ere was no signi�cant difference
between the three surgical groups, and those who progressed
to �brosis also became more insulin resistant. ey also
found a positive correlation between the presence of hepatic
steatosis/ballooning and insulin resistance (Table 3).
2.4. Malabsorptive Procedures. Only two studies were found
that utilised malabsorptive bariatric surgical techniques to
examine the effects on NAFLD [38, 39]. Kral et al. 
performed liver biopsies on biliopancreatic diversion and
then on followup 41 ± 25 months later on 104 patients.
Biopsies were graded on the basis of steatosis, �brosis,
and in�ammation by a blinded hepatopathologist. Steatosis
grades decreased in correlation with weight loss as expected,
and as seen in previous studies. However, they observed
a postoperative increase in �brosis in 40%, a decrease in
27%, and no change in 33%. e changes in �brosis were
related to initial �brosis grades; those with a higher grade of
baseline grade saw an increase. Eighteen of the initial cohort
developed new mild in�ammation.
Keshishian et al.  studied repeat liver biopsies on
78 patients at the time of, and 6–36 months aer duodenal
switch (DS) operation. Liver function tests had worsened
by the 6-month period, but normalised by 12 month, and
tion had also slightly worsened at the 6-month mark, but
then improvements were seen at and beyond 12 months.
is initial worsening was attributed to the rapid weight loss
experienced early in patients undergoing bariatric surgery.
By three years, the histological degree of steatosis had
improved by 60% and the severity of in�ammation improved
by 3 grades. ey concluded that no hepatic detrimental
effects are seen beyond 6 months; however, �brosis was not
examined in this study (Table 4).
3. Bariatric Surgery and Metabolic Syndrome
Several studies have shown bene�t of utilising bariatric
surgery as a mode of treatment for metabolic syndrome and
its components. To et al.  examined the effects of sleeve-
gastrectomy, a restrictive procedure which permanently
who ful�lled the criteria for metabolic syndrome. Postop-
erative followups were conducted at 6, 12, and 24 months.
ey found improvements in all features of metabolic syn-
fasting glucose as well as an increase in HDL cholesterol.
e metabolic improvements did not correlate with the
degree of weight loss, and the most drastic improvements
were observed within the �rst 6 months following surgery,
when signi�cant weight reduction occurred.
A recent Brazilian study  speci�cally looked at the
Roux-en-Y gastric bypass. In the cohort of 149 patients
there was a signi�cant resolution of metabolic syndrome
postoperatively on the 180-day follow-up assessment. A later
Brazilian study conducted by Júnior et al.  looked at
35 patients who underwent the RYGB; 27 of these had a
diagnosis of metabolic syndrome. When these patients were
followed up 34.4 ± 15 months aer surgery, not only was
a reduction in BMI observed, only 2 patients ful�lled the
criteria for metabolic syndrome. Improvements in abdom-
inal circumference, fasting glucose, blood pressure, HDL-
cholesterol, and triglycerides were also seen. Inabnet III et
al.  searched “e National Database for the American
Society for Metabolic and Bariatric Surgery Centre of Excel-
lence Program” for patients with metabolic syndrome that
were undergoing bariatric surgery between 2007 and 2010.
Of this group of 23,106 patients, 62% underwent RYGB, 32%
had gastric banding, 4.5% had sleeve gastrectomy, and only
1.5% had biliopancreatic diversion with duodenal switch.
Despite the fact that the metabolic syndrome group had a
higher prevalence of postoperative complications, there was
an improvement in their comorbid state.
Bretón et al.  looked at 46 morbidly obese patients
undergoing laparoscopic bypass surgery, of which twenty-
eight ful�lled the criteria for metabolic syndrome preoper-
atively. On follow up 2 years aer surgery, they found res-
olution of hypertension, dysglycaemia, and dyslipidaemia in
Pontiroliet al.  compared thelong-term effects ofrestric-
tive (gastric banding) and malabsorptive (biliopancreatic
diversion) bariatric procedures on metabolic syndrome with
a control group whom utilised conservative measures (diet
eters of diabetes, hypertension, and metabolic syndrome
disappeared more in the surgical group than the control.
gastric banding in reducing BMI, and neither surgical group
showed any new diagnoses of metabolic syndrome, whereas
the control group did, suggesting that surgery is a more
successful mode of treatment for metabolic syndrome.
e Surgical Department of the Mayo Clinic  carried
out a retrospective study between 1990 and 2003 on 337
6Journal of Obesity
Potential treatment of NAFLD
F 1: Schematic �gure illustrating the complex potential factors that associated with bariatric surgery that may have the potential role in
the treatment of NAFLD.
patients evaluated for bariatric surgery. Two groups were
established; 180 undergoing RYGB (156 had metabolic syn-
drome) and 157 nonoperative patients (133 had metabolic
syndrome) enrolled in a weight reduction program. Aer
a mean followup of 3.4 years, all components of metabolic
syndrome improved in the surgical group; there was a
reduction in the prevalence of metabolic syndrome from
87% to 29%, while nonoperative patient group also showed
a decrease in the prevalence of metabolic syndrome, from
85% to 75%. ese �ndings suggest that RYGB induces a
considerable and persistent improvement in the prevalence
of metabolic syndrome.
Nugent et al. (2008)  assessed the impact of bariatric
surgery on metabolic syndrome, by looking at 286 patients;
160 underwent restrictive procedures, 78 had malabsorptive,
and 48 had a combination procedure. Aer 297 ± 271 days,
263 patients were followed up. Prior to surgery 40% had
metabolic syndrome, compared to only 10% on followup.
Furthermore, all components of metabolic syndrome also
improved; waist circumference, BMI, fasting serum triglyc-
erides, and fasting glucose. e prevalence of type 2 diabetes
also fell from 30% to 10%. Madan et al.  found in
their study that the prevalence of metabolic syndrome fell
from 60% to 2% in their cohort of 53 patients undergoing
laparoscopic gastric bypass surgery. Lee et al.  found
metabolic syndrome to be present in 52% of morbidly obese
individuals enrolling in a bariatric surgery program, and
on 1-year followup, there was a resolution rate of 95.6%
of the condition. A growing body of evidence also exists
to demonstrate that an improvement in the components
of metabolic syndrome also takes place following bariatric
surgery [82–85]. Carson et al.  reported that there was
an improvement or complete resolution of hypertension in
70% of patients undergoing gastric bypass surgery. Two
studies looking speci�cally at dyslipidaemia found a resolu-
tion in hyperlipidaemia in morbidly obese patients following
bariatric surgery, which was maintained at 1-year followup
 and 5-year follow-up .
ese �ndings of resolution of the components of
metabolic syndrome, and improvement in the condition
itself following bariatric surgery, are clearly indicative that
currently bariatric surgery is an effective and safe surgical
treatment option for this syndrome.
4. Pathophysiological Changes with
Bariatric Surgery That Havethe Potential to
e full understanding of the pathogenesis behind NAFLD
is not yet established and probably involves complex factors
that alter different metabolic events (Figure 1). e key
pathognomonic feature of pathogenesis of NAFLD is insulin
resistance and dyslipidaemia. Obesity and central obesity
are associated with an increase in free fatty acid supply to
the liver and ultimately insulin resistance [89–91]. Excessive
consumption of glucose or sucrose is also shown to promote
NAFLD due to the increase of de novo lipogenesis. In addi-
tion, fatty food may also precipitate NASH. ere is a strong
link between insulin resistance and excessive deposition of
triglyceride in the hepatocytes, which is the hallmark for
diagnosis of NAFLD. e excessive/ectopic fat deposition
in the liver could be due to increased fatty acid delivery
from adipose tissue, increased synthesis of fatty acid via
Journal of Obesity7
the de novo pathway, increased dietary fat, decreased mito-
chondrial oxidation, decreased clearance of VLDL particles,
or these factors in combination [5, 6].
Fat tissue is now considered a metabolically active
endocrine organ producing proin�ammatory cytokines
including TNF-𝛼𝛼, IL-6, and IL-8, and there is evidence to
support the activation of other in�ammatory pathways,
oxidative stress, and the de novo pathway by TNF-𝛼𝛼. In�am-
mation is associated insulin resistance resulting in increased
lipolysis in adipose tissue, increased NEFA uptake by
hepatocytes, and increased triglyceride synthesis in the
liver. As a consequence of abnormal fat accumulation in the
hepatocytes, there is marked derangement in the insulin
signalling pathways in the liver . Adiponectin has been
shown to decrease de novo fatty acid synthesis and enhance
fat oxidation, with levels of adiponectin increasing aer
with insulin resistance and hyperlipidaemia and low level
of adiponectin was shown in NAFLD independent of the
components of the metabolic syndrome .
Bariatric surgery is likely to have potential bene�t in
ameliorating the following factors that contribute in marked
way to the pathogenesis of NAFLD.
(A) Insulin resistance. One of the immediate bene�ts of
bariatric surgery before weight loss is remission of
type 2 diabetes and improvement of insulin sensitiv-
ity. Pories et al. showed that in 608 obese with type
2 diabetes, 83% have normoglycaemia before weight
loss but within days of RYGB . A meta-analysis
of 136 bariatric surgery studies including 22094
individuals con�rmed an overall 84% remission of
type 2 daibetes aer RYGB . Interestingly, two
large multicentre studies showed similar outcomes in
treating type 2 diabetes with one study showed 92%
decrease in diabetes [60, 61].
(B) Dyslipidaemia. Several studies showed that bariatric
surgery is associated with signi�cant improvement in
the lipid pro�le. For instance, accumulating body of
evidence showed that bariatric surgery is associated
with marked decrease in LDL-c, triglyceride, and
lipoprotein (A). Furthermore, bariatric surgery is not
only associated with stopping lipid lowering medi-
cation but also stopping antihypertensive medication
(C) In�ammation. Obesity is associated with low-grade
chronic in�ammation and adipose tissue is a main
source of excess production of cytokines like tumour
1, IL-8, monocyte chemoattractant protein-1, and
C reactive protein (CRP) . Excess production
of TNF-𝛼𝛼 and low adiponectin are associated with
insulin resistance and nonalcoholic fatty liver .
Interestingly, IL-18 has the capacity to stimulate
the secretion of TNF-𝛼𝛼. Furthermore, TNF-𝛼𝛼 plays
crucial role in the pathogenesis of NAFLD. Bariatric
surgery has been shown to ameliorate insulin resis-
tance, improve the adiponectin level, and decrease
IL-18, CRP, and TNF-𝛼𝛼. Interestingly, RYGB in
�ve individuals with diabetes was associated with a
decrease of CRP and leptin with no alteration in the
level of adiponectin and TNF-𝛼𝛼 [96, 97]. erefore,
it is possible to suggest that bariatric surgery has the
potential bene�t of treating obesity and decreasing
the low-grade associated in�ammatory state.
(D) Adiponectin. Is known to be antiatherogenic, anti-
in�ammatory, and antidiabetogenic and is decreased
type 2 diabetes, atherosclerosis, and acute coronary
syndrome [92, 93].
(E) Weight loss. Currently the only effective treatment for
NAFLD is weight loss. ere is an agreement in the
surgery is associated with sustained and signi�cant
weight loss [21–31].
ciated with a decrease in Ghrelin, which is known
to; stimulate insulin counter regulatory hormones,
decrease adiponectin, and block hepatic insulin sig-
nalling. Furthermore, RGYB is associated with an
increase in glucagon like peptide-1 (GLP-1) which
subsequently enhances glucose tolerance by enhanc-
ing insulin secretion, suppressing glucagon produc-
tion, inhibiting gastric emptying, and increasing B-
cell mass. Other hormones that suppress appetite and
produced in excess with bariatric surgery are peptide
YY (PYY) and Oxyntomodulin .
rates of the metabolic syndrome and its hepatic manifes-
tation, NAFLD. e therapeutic options for the treatment
of obesity and NAFLD include lifestyle adjustments, phar-
macotherapy, and surgical interventions. With regards to
sustained weight loss, in those who adopt lifestyle changes
such as dieting, 33–66% subsequently regain more weight
than lost whilst dieting. Similarly, pharmacotherapy results
as long as the medication is taken, as weight gain is oen
observed once the medication has ceased.
Bariatric surgery appears to show more promise than
its noninvasive counterparts. Subjects experience a 40–71%
loss of excess body weight following surgery, and weight
loss is sustained. Importantly, weight loss is one of the �rst
line recommendations to individuals with NAFLD. RYGB
is associated with complete remission of type 2 diabetes,
suggesting greater potential bene�t in treating NAFLD. e
mechanism of how bariatric surgery plays a role as potential
treatment of NAFLD is complex and not fully understood
(Figure 1). It is possible to suggest that in addition to weight
loss, bariatric surgery normalizes insulin resistance and
decreases dyslipidaemia and in�ammation. e alteration
in gut hormone production following bariatric surgery and
its role in insulin sensitivity has generated a lot of interest.
Urgent large scale clinical studies are needed to further
8 Journal of Obesity
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