**2. Benefits and risks of bariatric surgery on NAFLD**

Sleeve gastrectomy: Different studies were done to find out the effect of sleeve gastrectomy on NAFLD. Algooneh et al. observed that 56% of total 84 transabdominal ultrasonographically diagnosed NAFLD patients showed complete resolution of hepatic steatosis 3.3 years (average) after isolated sleeve gastrectomy [14]. Karcz et al. found that there was significant reduction (>50%) of transaminases in NASH patients within 6 months of isolated sleeve gastrectomy [15]. Parveen-Raj et al. did a prospective observational trial and found that surgically induced weight loss improved NAFLD histology significantly 6 months after isolated sleeve gastrectomy in morbidly obese patients [16].

LAGB: There have been several studies showing the effects of LAGB on NAFLD. Most of the studies reported improvement of hepatic steatosis, steatohepatitis, and fibrosis, but some studies showed mild increase in fibrosis.

Few LAGB studies with their effects on NAFLD are mentioned in **Table 1**.

Biliopancreatic diversion (BPD) and biliopancreatic diversion with duodenal switch (BPD with DS): Both procedures produce long-term malabsorption and severe weight loss. They are not widely done. Their effects on NAFLD are summarized in two studies in **Table 2**.

In patients with BPD with DS, the transient deterioration of transaminases and steatohepatitis seen in the first 6 months postoperatively was possibly due to rapid weight loss. Transaminases became normalized by 12 months. Then there


#### **Table 1.**

*Summary of LAGB studies showing effects on NAFLD.*


#### **Table 2.**

*Summary of effects of BPD and BPD with DS on NAFLD.*


**65**

insulin resistance.

status.

**Table 3.**

mentioned in **Table 3**.

**3. How does bariatric surgery help NAFLD?**

*Non-alcoholic Fatty Liver Disease and Surgery DOI: http://dx.doi.org/10.5772/intechopen.86146*

Furuya et al. [33] ↓ Steatosis

Weiner et al. [34] ↓ Steatosis

De Almeida et al. [35] ↓ Steatosis

*Summary of effects of RYGB on NAFLD.*

was progressive improvement of steatosis and steatohepatitis up to 3 years. In patients who had BPD, the appearance of mild fibrosis was possibly related to severe diarrhea, hypoalbuminemia, some intake of alcohol, and postmenopausal

**Study Outcome Sample size Follow-up**

18 24 months

116 18.6 ± 8.3 months

16 23.5 ± 8.4 months

↓ Fibrosis

↓ Steatohepatitis ↓ Fibrosis

↓ Steatohepatitis ↓ Fibrosis

Roux-en-Y gastric bypass (RYGB): Effects of RYGB have been studied extensively in different studies. Most of the studies showed improvement of steatosis, steatohepatitis, and hepatic fibrosis. Summary of some of the RYGB studies are

1.By achieving weight loss: Weight loss is the key in the treatment of NAFLD [36]. Seven to ten percent of weight loss by lifestyle modification has been shown to improve hepatic steatosis and steatohepatitis [37]. Significant and

2.By improving insulin resistance: Obesity is associated with insulin resistance, i.e., insulin receptors fail to work. How does this happen? Adipose tissue works as a metabolically active endocrine organ and produces proinflammatory cytokines—TNF-α, IL-1, IL-6, IL-8, IL-18, and C-reactive protein [38]. In obesity, excessive production of these cytokines occurs leading to a proinflammatory state which is associated with insulin resistance. Adiponectin is a fat cell hormone produced in the white adipose tissue. It plays an important role in the regulation of glucose and fat metabolism in insulin-sensitive tissues. It increases fatty acid oxidation and decreases de novo synthesis of fatty acid. In diet-induced obesity, the circulating level of adiponectin is paradoxically decreased [39]. Hypoadiponectinemia in obesity is associated with insulin resistance [40]. In obesity, excessive intraperitoneal fat promotes free fatty acid (FFA) reflux directly into the hepatocytes via the portal vein [41]. FFA metabolites (long-chain acyl-CoAs and diacylglycerol) then transfer cytoplasmic protein kinase Cs to the cell membrane. Subsequently, intracellular portions of insulin receptors are phosphorylated by protein kinase C leading to

As a result of insulin resistance, lipolysis occurs in the adipose tissue with increased levels of plasma FFA and excessive influx of FFA into the hepatocytes. In the hepatocytes, fatty acid oxidation is inhibited, and de novo synthesis of fatty acid occurs leading to triglyceride synthesis and hepatic steatosis.

sustained weight loss is common after bariatric surgery.

*Non-alcoholic Fatty Liver Disease and Surgery DOI: http://dx.doi.org/10.5772/intechopen.86146*


**Table 3.**

*Liver Disease and Surgery*

**Study Type of** 

Keshishian et al. [24]

**Table 2.**

**Table 1.**

**surgery**

*Summary of LAGB studies showing effects on NAFLD.*

Luyckx et al. [17] ↓ Steatosis

Stratopoulas et al. [19] ↓ Steatosis

Jaskiewicz et al. [20] ↓ Steatosis

Phillips et al. [21] ↓ Steatosis

Dixon et al. [22] ↓ Steatosis

Mathurin et al. [23] ↓ Steatosis

BPD with DS

*Summary of effects of BPD and BPD with DS on NAFLD.*

Matter et al. [27] ↓ Steatosis

Clark et al. [28] ↓ Steatosis

Silverman et al. [29] ↓ Steatosis

Lie et al. [30] ↓ Steatosis

Barker et al. [31] ↓ Steatosis

Kral et al. [25] BPD Severe fibrosis decreased in 27%

**Outcome Sample** 

Transaminases and NASH worsened at 6 months Steatosis and NASH decreased after 6 months

**Study Outcome Sample size Follow-up**

Busetto et al. [18] ↓ Steatosis 6 24 weeks

↑ Mild hepatitis

↓ Steatohepatitis ↓ Fibrosis

↓ Steatohepatitis

↓ Gamma-glutamyl transferase

↓ Steatohepatitis ↓ Fibrosis

↓ Fibrosis

and mild fibrosis appeared in 40%: 41 ± 25 months after BPD

**Study Outcome Sample size Follow-up** Mottin et al. [26] ↓ Steatosis 90 12 months

↓ Fibrosis

↓ Steatohepatitis ↓ Fibrosis

↓ Fibrosis

↓ Steatohepatitis ↓ Fibrosis

↓ Steatohepatitis ↓ Fibrosis

Klein et al. [32] ↓ Steatosis 7 12 months

**size**

90 12 months

16 305 ± 131 days

91 18.4 months

39 18 months

19 21.4 months

**Follow-up**

78 36 months

69 27 ± 15 months

51 17 months

87 41 months

29 3 months

60 29.5 ± 10 months

381 60 months

104 41 ± 25 months

**64**

*Summary of effects of RYGB on NAFLD.*

was progressive improvement of steatosis and steatohepatitis up to 3 years. In patients who had BPD, the appearance of mild fibrosis was possibly related to severe diarrhea, hypoalbuminemia, some intake of alcohol, and postmenopausal status.

Roux-en-Y gastric bypass (RYGB): Effects of RYGB have been studied extensively in different studies. Most of the studies showed improvement of steatosis, steatohepatitis, and hepatic fibrosis. Summary of some of the RYGB studies are mentioned in **Table 3**.
