Omega-3 fatty acids and liver disease

Liver transplantation for non-alcoholic fatty liver disease: indications and post-transplant management

Non-alcoholic fatty liver disease (NAFLD) is currently the fastest growing indication to liver transplantation (LT) in Western Countries, both for end stage liver disease and hepatocellular carcinoma. NAFLD/non-alcoholic steatohepatitis (NASH) is often expression of a systemic metabolic syndrome; therefore, NAFLD/NASH patients require a multidisciplinary approach for a proper pre-surgical evaluation, which is important to achieve a post-transplant outcome comparable to that of other indications to LT. NAFLD/NASH patients are also at higher risk of post-transplant cardiovascular events, diabetes, dyslipidemia, obesity, renal impairment and recurrent NASH. Lifestyle modifications, included diet and physical activity, are key to improve survival and quality of life after transplantation. A tailored immunosuppressive regimen may be proposed in selected patients. Development of new drugs for the treatment of recurrent NASH is awaited.

Management of pediatric intestinal failure related to short bowel syndrome

Intestinal failure (IF) secondary to short bowel syndrome is a challenging and complex medical condition with significant risk for surgical and medical complications. Significant advancements in the care of this patient population have led to improved survival rates. Due to their intensive medical needs children with IF are at risk for long-term complications that require comprehensive management and close monitoring. The purpose of this paper is to review the available literature emphasizing the surgical aspects of care for children with IF secondary to short bowel syndrome. A key priority in the surgical care of this patient population includes strategies to preserve available bowel and maximize its function. Utilization of novel surgical techniques and autologous bowel reconstruction can have a significant impact on children with IF secondary to short bowel syndrome related to the function of their bowel and ability to achieve enteral autonomy. It is also important to understand the potential long-term complications to ensure strategies are put in place to mitigate risk with early detection to improve long-term outcomes.

Technologies for Solubility, Dissolution and Permeation Enhancement of Natural Compounds

The current review is based on the advancements in the field of natural therapeutic agents which could be utilized for a variety of biomedical applications and against various diseases and ailments. In addition, several obstacles have to be circumvented to achieve the desired therapeutic effectiveness, among which limited dissolution and/or solubility and permeability are included. To counteract these issues, several advancements in the field of natural therapeutic substances needed to be addressed. Therefore, in this review, the possible techniques for the dissolution/solubility and permeability improvements have been addressed which could enhance the dissolution and permeability up to several times. In addition, the conventional and modern isolation and purification techniques have been emphasized to achieve the isolation and purification of single or multiple therapeutic constituents with convenience and smarter approaches. Moreover, a brief overview of advanced natural compounds with multiple therapeutic effectiveness have also been anticipated. In brief, enough advancements have been carried out to achieve safe, effective and economic use of natural medicinal agents with improved stability, handling and storage.

Perioperative omega-3 fatty acids for liver surgery: A meta-analysis of randomized controlled trials

INTRODUCTION

The effect of perioperative omega-3 fatty acids for liver surgery remained controversial. We conducted a systematic review and meta-analysis to explore the influence of omega-3 fatty acids versus placebo in patients undergoing liver surgery.

METHODS

We have searched PubMed, EMbase, Web of science, EBSCO, and Cochrane library databases through May 2020, and included randomized controlled trials (RCTs) assessing the effect of omega-3 fatty acids versus placebo for liver surgery. This meta-analysis was performed using the random-effect model.

RESULTS

Five RCTs were included in the meta-analysis. Overall, compared with control group for liver surgery, omega-3 fatty acids were associated with substantially reduced incidence of infection (odd ratio [OR]=0.56; 95% confidence interval [CI] =0.34-0.91; P = .02), but revealed no remarkable influence on complications (OR = 0.60; 95% CI = 0.29-1.24; P = .17), mortality (OR = 0.76; 95% CI = 0.06-9.37; P = .83), liver failure (OR = 0.72; 95% CI = 0.10 to 5.00; P = 0.74), biliary leakage (OR=1.24; 95% CI = 0.41 to 3.76; P = .70), bleeding (OR = 1.76; 95% CI = 0.63-4.95; P = .28), or ileus (OR = 0.39; 95% CI = 0.07-2.05; P = .27).

CONCLUSION

Perioperative omega-3 fatty acids may be beneficial to reduce the incidence of infection after liver surgery.

NAFLD and liver transplantation: Disease burden, current management and future challenges

Non-alcoholic fatty liver disease (NAFLD), specifically its progressive form non-alcoholic steatohepatitis (NASH), represents the fastest growing indication for liver transplantation in Western countries. Diabetes mellitus, morbid obesity and cardiovascular disease are frequently present in patients with NAFLD who are candidates for liver transplantation. These factors require specific evaluation, including a detailed pre-surgical risk stratification, in order to improve outcomes after liver transplantation. Moreover, in the post-transplantation setting, the incidence of cardiovascular events and metabolic complications can be amplified by immunosuppressive therapy, which is a well-known driver of metabolic alterations. Indeed, patients with NASH are more prone to developing early post-transplant complications and, in the long-term, de novo malignancy and cardiovascular events, corresponding to higher mortality rates. Therefore, a tailored multidisciplinary approach is required for these patients, both before and after liver transplantation. Appropriate candidate selection, lifestyle modifications and specific assessment in the pre-transplant setting, as well as pharmacological strategies, adjustment of immunosuppression and a healthy lifestyle in the post-transplant setting, play a key role in correct management.

Vortex fluidic mediated encapsulation of functional fish oil featuring in situ probed small angle neutron scattering

Major challenges for optimizing the benefits of fish oil on human health are improved bioavailability while overcoming the strong odor and avoiding significant oxidation of the omega-3 polyunsaturated fatty acids (PUFAs). The scalable continuous flow thin film vortex fluidic device (VFD) improves the Tween 20 encapsulation of fish oil relative to conventional homogenization processing, with the fish oil particles significantly smaller and the content of the valuable omega-3 fatty acids higher. In addition, after 14 days storage the remaining omega-3 fatty acids content was higher, from ca 31.0% for raw fish oil to ca 62.0% of freeze-dried encapsulated fish oil. The VFD mediated encapsulated fish oil was used to enrich the omega-3 fatty acid content of apple juice, as a model water-based food product, without changing its sensory values. The versatility of the VFD was further demonstrated in forming homogenous suspensions of fish oil containing water-insoluble bioactive molecules, curcumin and quercetin. We have also captured, for the first time, real-time structural changes in nanoencapsulation by installing a VFD with in in situ small angle neutron scattering. Real-time measurements afford valuable insights about self-assembly in solution.

Medical management of metabolic and cardiovascular complications after liver transplantation

Liver transplantation represents the only curative option for patients with end-stage liver disease, fulminant hepatitis and advanced hepatocellular carcinoma. Even though major advances in transplantation in the last decades have achieved excellent survival rates in the early post-transplantation period, long-term survival is hampered by the lack of improvement in survival in the late post transplantation period (over 5 years after transplantation). The main etiologies for late mortality are malignancies and cardiovascular complications. The latter are increasingly prevalent in liver transplant recipients due to the development or worsening of metabolic syndrome and all its components (arterial hypertension, dyslipidemia, obesity, renal injury, etc.). These comorbidities result from a combination of pre-liver transplant features, immunosuppressive agent side-effects, changes in metabolism and hemodynamics after liver transplantation and the adoption of a sedentary lifestyle. In this review we describe the most prevalent metabolic and cardiovascular complications present after liver transplantation, as well as proposing management strategies.

Review article: diagnosis and management of intestinal failure-associated liver disease in adults

BACKGROUND

Hepatic disturbances in the context of intestinal failure and parenteral nutrition (PN) are frequently encountered and carry a significant burden of morbidity and sometimes mortality. The term intestinal failure-associated liver disease (IFALD) refers to liver injury due to intestinal failure and associated PN, in the absence of another evident cause of liver disease, encompassing a spectrum of conditions from deranged liver enzymes, steatosis/ steatohepatitis, cholestasis as well as progressive fibrosis, cirrhosis and end-stage liver disease.

AIMS

To present an up to date perspective on the diagnosis/definition, aetiologies and subsequent management of IFALD and to explore future consideration for the condition, including pharmacological therapies RESULTS: In adults using long-term PN for benign chronic intestinal failure, 1%-4% of all deaths are attributed to IFALD. The aetiology of IFALD is multifactorial and can be broadly divided into nutritional factors (eg lipid emulsion type) and patient-related factors (eg remaining bowel anatomy). Given its multifaceted aetiology, the management of IFALD requires clinicians to investigate a number of factors simultaneously. Patients with progressive liver disease should be considered for combined liver-intestine transplantation, although multivisceral grafts have a worse prognosis. However, there is no established non-invasive method to identify progressive IFALD such that liver biopsy, where appropriate, remains the gold standard.

CONCLUSION

A widely accepted definition of IFALD would aid in diagnosis, monitoring and subsequent management. Management can be complex with a number of factors to consider. In the future, dedicated pharmacological interventions may become more prominent in the management of IFALD.

Recommendations for Management and Treatment of Nonalcoholic Steatohepatitis

The prevalence of nonalcoholic liver disease (NAFLD) is increasing worldwide in conjunction with the epidemic increase in obesity and metabolic risk factors. Consequently, NAFLD has become a leading indication for liver transplantation. Although genetic factors play an important role in the pathogenesis of NAFLD, detrimental lifestyle trends favoring a calorically unrestricted diet rich in carbohydrates and unsaturated fat, prolonged sedentary periods or limited physical activity have major metabolic implications. In aggregate these physiological dysregulations constitute the main risk factors for the metabolic syndrome and NAFLD. The cornerstone of the treatment of NAFLD, is lifestyle changes, including modifications to diet and physical activity, to reduce body weight and liver fat, however adherence is notoriously poor and the epidemic of NAFLD continues to grow unimpeded. In the face of this unmet clinical need, the pharmacologic therapy of NAFLD has been expanding as the varied mechanistic pathways of NAFLD are elucidated. Beyond these approaches to treating NAFLD, the prevention of other liver diseases is additionally important. Chief among these is alcoholic liver disease, and heavy use is detrimental irrespective of underlying NAFLD. However, the impact of mild to moderate alcohol use in patients with mild or nonadvanced forms NAFLD is undefined. This article summarizes the results of the International Liver Transplantation Society consensus meeting on NAFLD in liver transplantation. It describes the available evidence and provides consensus guidance on the lifestyle and pharmacologic therapies of NAFLD, and the consensus position on alcohol use in patients with NAFLD.

Variation in the Plasma Levels of Polyunsaturated Fatty Acids in Control vis-à-vis Nonalcoholic Fatty Liver Disease Subjects and Its Possible Association with Gut Microbiome

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH) are becoming a major cause of chronic liver diseases globally. Polyunsaturated fatty acids (PUFA) have been postulated as a potential treatment for NAFLD. They can be obtained from diet and are also endogenously synthesized by enzymes delta-6-desaturase (D6D), delta-5-desaturase, and elongases. The current study is aimed at investigating the differences in the intake and levels of plasma PUFA between NAFLD patients and controls in Asian Indians. This correlation further propelled a pilot study to check for the differences in the gut microbiome of NASH subjects versus controls.

METHODS

One hundred forty-seven subjects were recruited and were grouped into healthy controls and cases. Subjects filled a food frequency questionnaire to assess PUFA intake. Plasma samples were subjected to gas chromatography analysis. For characterizing the gut microbiome, fecal samples of 20 NASH and healthy controls were analyzed by 16s rRNA gene sequencing. Alpha and beta diversity metrics and taxonomic analysis were carried out.

RESULTS

Plasma levels of eicosapentaenoic acid, γ-linoleic acid and D6D enzyme activity were significantly lower in cases. Dietary intake of total n-6 and n-3 PUFA did not differ between the two groups. Relative abundance of Streptococcus and Clostridium ramosum was significantly higher in NASH patients compared with healthy controls.

CONCLUSION

This study demonstrates, for the first time, decreased D6D enzyme activity and plasma PUFA levels in NAFLD patients. Furthermore, it demonstrates gut dysbiosis in histologically proven NASH patients vis-à-vis healthy controls.

Cardiovascular risk after orthotopic liver transplantation, a review of the literature and preliminary results of a prospective study

Improved surgical techniques and greater efficacy of new anti-rejection drugs have significantly improved the survival of patients undergoing orthotopic liver transplantation (OLT). This has led to an increased incidence of metabolic disorders as well as cardiovascular and cerebrovascular diseases as causes of morbidity and mortality in OLT patients. In the last decade, several studies have examined which predisposing factors lead to increased cardiovascular risk (i.e., age, ethnicity, diabetes, NASH, atrial fibrillation, and some echocardiographic parameters) as well as which factors after OLT (i.e., weight gain, metabolic syndrome, immunosuppressive therapy, and renal failure) are linked to increased cardiovascular mortality. However, currently, there are no available data that evaluate the development of atherosclerotic damage after OLT. The awareness of high cardiovascular risk after OLT has not only lead to the definition of new but generally not accepted screening of high risk patients before transplantation, but also to the need for careful patient follow up and treatment to control metabolic and cardiovascular pathologies after transplant. Prospective studies are needed to better define the predisposing factors for recurrence and de novo occurrence of metabolic alterations responsible for cardiovascular damage after OLT. Moreover, such studies will help to identify the timing of disease progression and damage, which in turn may help to prevent morbidity and mortality for cardiovascular diseases. Our preliminary results show early occurrence of atherosclerotic damage, which is already present a few weeks following OLT, suggesting that specific, patient-tailored therapies should be started immediately post OLT.

Dietary patterns and serum gamma-glutamyl transferase in Japanese men and women

Background

Although specific foods and nutrients have been examined as potential determinants of serum gamma-glutamyl transferase (GGT) concentrations, the relationship between dietary patterns and GGT remains unknown. The present cross-sectional study aimed to determine relationships between dietary patterns and GGT concentrations, and the effects of lifestyle factors on GGT.

Methods

Relationships between dietary patterns and GGT were analyzed in 9803 Japanese individuals (3723 men and 6080 women age 40–69 years) without a history of liver diseases or elevated serum aminotransferase. We examined major dietary patterns by factor analysis of 46 items determined from a validated, short food frequency questionnaire.

Results

We defined dietary patterns as healthy, Western, seafood, bread, and dessert. The healthy pattern was inversely related to GGT in men (odds ratio [OR] for highest vs lowest quartile, 0.72; 95% confidence interval [CI], 0.57–0.92; P < 0.01 for trend) and women (OR 0.82; 95% CI, 0.66–1.0; P = 0.05 for trend), whereas the seafood pattern was positively related to GGT in men (OR 1.27; 95% CI, 1.01–1.61; P = 0.03 for trend) and women (OR 1.21; 95% CI, 0.98–1.49; P = 0.05 for trend). Male-specific inverse associations with GGT were found for bread and dessert patterns (OR 0.63; 95% CI, 0.50–0.80 and OR 0.53; 95% CI, 0.41–0.68, respectively; P < 0.01 for both trends). Seafood or bread patterns and alcohol consumption significantly interacted with GGT in men (P = 0.03 and <0.01 for interaction, respectively) and between the dessert pattern and body mass index or smoking habit in women (P = 0.03 and <0.01, respectively, for interaction).

Conclusions

Dietary patterns may be important determinants of GGT, and their possible clinical implications warrant further investigation.

Anti-inflammatory and anti-fibrotic profile of fish oil emulsions used in parenteral nutrition-associated liver disease

Home parenteral nutrition (PN) is associated with many complications including severe hepatobiliary dysfunction. Commercial ω-6 fatty acid-soybean based-lipid emulsions in PN may mediate long term PN associate liver disease (PNALD) whereas ω-3-fish oil parenteral emulsions have shown to reverse PNALD in children. However, its clinical effectiveness in adults has been scarcely reported. In this work, we study the role of soybean and fish oil lipid commercial emulsions on inflammatory and profibrotic liver markers in adults with long term PNALD and in in vitro cellular models. Inflammatory and profibrotic markers were measured in serum of ten adults with long term PNALD and in culture supernatants of monocytes. Liver epithelial to mesenchymal transition (EMT) was induced by transforming growth factor beta 1 (TGFβ1) to evaluate in vitro liver fibrosis. Omegaven®, a 100% fish oil commercial emulsion, was infused during four months in two patients with severe long term PNALD reversing, at the first month, the inflammatory, profibrotic and clinical parameters of PNALD. The effect was maintained during the treatment course but impaired when conventional lipid emulsions were reintroduced. The other patients under chronic soybean oil-based PN showed elevated inflammatory and profibrotic parameters. In vitro human monocytes stimulated with lipopolysaccharide induced a strong inflammatory response that was suppressed by Omegaven®, but increased by soybean emulsions. In other experiments, TGFβ1 induced EMT that was suppressed by Omegaven® and enhanced by soybean oil lipid emulsions. Omegaven® improves clinical, anti-inflammatory and anti-fibrotic parameters in adults with long-term home PNALD.

Reactive oxygen and nitrogen species in steatotic hepatocytes: a molecular perspective on the pathophysiology of ischemia-reperfusion injury in the fatty liver

SIGNIFICANCE

Hepatic ischemia-reperfusion (IR) injury results from the temporary deprivation of hepatic blood supply and is a common side effect of major liver surgery (i.e., transplantation or resection). IR injury, which in most severe cases culminates in acute liver failure, is particularly pronounced in livers that are affected by non-alcoholic fatty liver disease (NAFLD). In NAFLD, fat-laden hepatocytes are damaged by chronic oxidative/nitrosative stress (ONS), a state that is acutely exacerbated during IR, leading to extensive parenchymal damage.

RECENT ADVANCES

NAFLD triggers ONS via increased (extra)mitochondrial fatty acid oxidation and activation of the unfolded protein response. ONS is associated with widespread protein and lipid (per)oxidation, which reduces the hepatic antioxidative capacity and shifts the intracellular redox status toward an oxidized state. Moreover, activation of the transcription factor peroxisome proliferator-activated receptor α induces expression of mitochondrial uncoupling protein 2, resulting in depletion of cellular energy (ATP) reserves. The reduction in intracellular antioxidants and ATP in fatty livers consequently gives rise to severe ONS and necrotic cell death during IR.

CRITICAL ISSUES

Despite the fact that ONS mediates both NAFLD and IR injury, the interplay between the two conditions has never been described in detail. An integrative overview of the pathophysiology of NAFLD that renders steatotic hepatocytes more vulnerable to IR injury is therefore presented in the context of ONS.

FUTURE DIRECTIONS

Effective methods should be devised to alleviate ONS and the consequences thereof in NAFLD before surgery in order to improve resilience of fatty livers to IR injury.

n-3 polyunsaturated fatty acids worsen inflammation and fibrosis in experimental nonalcoholic steatohepatitis

BACKGROUND & AIMS

n-3 polyunsaturated fatty acids (PUFA) ameliorate fatty liver in experimental models, but their effects on inflammation and fibrosis during steatohepatitis are either controversial or lacking. We compared the effects of supplementation with olive oil (OO) alone or OO and n-3 PUFA on the development and progression of experimental steatohepatitis.

METHODS

Balb/C mice (≥5 mice/group) were fed a methionine- and choline-deficient (MCD) diet or a control diet for 4 or 8 weeks. At the same time, mice were supplemented with n-3 PUFA (eicosapentaenoic and docosahexahenoic acid, 25 mg together with 75 mg OO), or OO alone (100 mg), two times a week by intragastric gavage.

RESULTS

After 8 weeks, mice on MCD/n-3 had higher ALT levels compared to MCD/OO and more severe scores of inflammation, including a significant increase in the number of lipogranulomas (26.4 ± 8.4 vs. 5.1 ± 5 per field, P < 0.001). Intrahepatic expression of TNF-α and CCL2 was higher in MCD/n-3 mice at both time points. In addition, increased expression of the profibrogenic genes TIMP-1 and TGF-β, and more severe histological scores of fibrosis were evident in MCD/n-3 mice. After 8 week of MCD diet, portal pressure was higher in mice receiving n-3 than in those on OO alone (5.1 ± 1.4 vs. 7.0 ± 0.9 mmHg, P < 0.05). Analysis of hepatic fatty acid profile showed that supplementation resulted in effective incorporation of n-3 PUFA.

CONCLUSIONS

In a murine model of steatohepatitis, supplementation with n-3 PUFA and OO is associated with more severe necro-inflammation and fibrosis than in mice treated with OO only.

Polyunsaturated fatty acids balance affects platelet NOX2 activity in patients with liver cirrhosis

BACKGROUND

NADPH-oxidase-2 up-regulation has been suggested in liver damage perpetuation via an oxidative stress-mediated mechanism. n-6/n-3 polyunsaturated fatty acids ratio derangement has been reported in liver disease.

AIM

To explore polyunsaturated fatty acids balance and its interplay with platelet oxidative stress in liver cirrhosis.

METHODS

A cross-sectional study in 51 cirrhotic patients and sex- and age-matched controls was performed. Serum polyunsaturated fatty acids and oxidative stress markers (urinary isoprostanes and serum soluble NADPH-oxidase-2-derived peptide) were measured. The effect on platelet oxidative stress of n-6/n-3 polyunsaturated fatty acids ratio in vitro and in vivo (1-week supplementation with 3g/daily n-3-polyunsaturated fatty acids) was tested.

RESULTS

Compared to controls, cirrhotic patients had significantly higher n-6/n-3 polyunsaturated fatty acids ratio. n-6/n-3 polyunsaturated fatty acids ratio correlated significantly with disease severity and oxidative stress markers. In vitro experiments showed that in Child-Pugh C patients' platelets incubation with low n-6/n-3 polyunsaturated fatty acids ratio resulted in dose-dependent decrease of radical oxigen species (-39%), isoprostanes (-25%) and NADPH-oxidase-2 regulation (-51%). n-3 polyunsaturated fatty acids supplemented patients showed significant oxidative stress indexes reduction.

CONCLUSIONS

In cirrhosis, n-6/n-3 polyunsaturated fatty acids imbalance up-regulates platelet NADPH-oxidase-2 with ensuing oxidative stress. Further study to evaluate if n-3 supplementation may reduce disease progression is warranted.

Modulation of hepatic steatosis by dietary fatty acids

Non-alcoholic fatty liver disease (NAFLD) describes a range of conditions caused by fat deposition within liver cells. Liver fat content reflects the equilibrium between several metabolic pathways involved in triglyceride synthesis and disposal, such as lipolysis in adipose tissue and de novo lipogenesis, triglyceride esterification, fatty acid oxidation and very-low-density lipoprotein synthesis/secretion in hepatic tissue. In particular, it has been demonstrated that hepatic de novo lipogenesis plays a significant role in NAFLD pathogenesis. It is widely known that the fatty acid composition of the diet influences hepatic lipogenesis along with other metabolic pathways. Therefore, dietary fat may not only be involved in the pathogenesis of hepatic steatosis, but may also prevent and/or reverse hepatic fat accumulation. In this review, major data from the literature about the role of some dietary fats as a potential cause of hepatic fat accumulation or as a potential treatment for NAFLD are described. Moreover, biochemical mechanisms responsible for an increase or decrease in hepatic lipid content are critically analyzed. It is noteworthy that both quantitative and qualitative aspects of dietary fat influence triglyceride deposition in the liver. A high-fat diet or the dietary administration of conjugated linoleic acids induced hepatic steatosis. In contrast, supplementation of the diet with krill oil or pine nut oil helped in the prevention and/or in the treatment of steatotic liver. Quite interesting is the “case” of olive oil, since several studies have often provided different and⁄or conflicting results in animal models.

Liver disease secondary to intestinal failure

IFALD is a common and potentially life-threatening condition for patients with SBS requiring long-term PN. There exists the potential for decreasing its incidence by optimizing the composition and the rate of infusion of parenteral solutions, by advocating a multidisciplinary approach, and by early referral for intestinal-liver transplantation to ensure long-term survival of patients with SBS.

Pharmacological agents for NASH

NASH is a common liver disease that increases liver-related mortality and reduces survival. The need for optimal management of NASH is therefore a priority for today's practicing hepatologist. The rationale for specific pharmacological therapy for NASH is based on the potential for disease progression and the difficulties that many patients have successfully implementing, in the long term, diet and lifestyle changes. Even in those that succeed, limited evidence exists that severe liver injury in patients with NASH can be reversed by diet and lifestyle measures alone. This Review provides a personal and critical assessment of the histological efficacy and safety of agents tested in randomized trials in patients with NASH.

Potential treatment of human nonalcoholic fatty liver disease with long-chain omega-3 polyunsaturated fatty acids

Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disorder in the Western world. Its prevalence has increased with the growing obesity epidemic, yet no definitive treatment has been developed, and optimal management remains a clinical challenge. Long-chain omega-3 polyunsaturated fatty acids (PUFAs) have recently been proposed as a potential treatment for liver inflammation associated with fat accumulation. PubMed literature and the ClinicalTrials.gov database were reviewed for the effects of omega-3 PUFA treatment on NAFLD, from mechanisms to the results of preclinical studies, human studies, and unreported ongoing clinical trials, using terms such as NAFLD, nonalcoholic steatohepatitis, omega-3 fatty acids, and fish oil. Articles published over the last 3-4 years were emphasized, and relevancy was ensured by scanning their abstracts. Preliminary studies have confirmed an ameliorative effect, yet the translation of promising early data into therapeutic interventions will have to await the results of larger, properly conducted, ongoing clinical trials.

Current concepts and management approaches in nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is the most common cause of liver dysfunction worldwide. NAFLD may progress to nonalcoholic steatohepatitis (NASH) and in turn cirrhosis. Importantly, hepatic cancer can occur in NASH in the absence of cirrhosis. The cardinal histologic feature of NAFLD is the presence of an excessive accumulation of triacylglycerols and diacylglycerols in hepatocytes. The presence of obesity and insulin resistance lead to an increased hepatic-free fatty acid (FFA) flux creating an environment appropriate for the development of NAFLD. The generation of toxic reactive oxygen species with the production of hepatic injury and inflammation as a consequence of FFA oxidation will ultimately lead to the initiation and progression of fibrosis. Lifestyle modifications specifically weight loss, physical exercise, and cognitive behavior therapy have been recommended as treatments for NASH. Dietary fructose is an independent risk factor for the development of NAFLD. Pioglitazone can be used to treat biopsy-proven NASH; however, its safety risks should be considered carefully. Greater consumption for coffee, independent of its caffeine component, has been associated with a significant reduced risk of advanced fibrosis in NASH. Additional data are needed before recommending bariatric surgery as an established option for the specific treatment of NASH.

Long-term medical management of the liver transplant recipient: what the primary care physician needs to know

Recognition, management, and prevention of medical complications and comorbidities after liver transplant is the key to improved long-term outcomes. Beyond allograft-related complications, metabolic syndrome, cardiovascular disease, renal dysfunction, and malignancies are leading causes of morbidity and mortality in this patient population. Primary care physicians have an important role in improving outcomes of liver transplant recipients and are increasingly relied on for managing these complex patients. This review serves to assist the primary care physician in the long-term management issues of liver transplant recipients.

Injury of the hepatic barrier and intestinal barrier in patients with small-for-size graft syndrome after partial liver transplantation: mechanisms and protective measures

The intestinal barrier can resist the invasion of pathogens and prevent harmful substances from going into blood circulation to maintain the stability of internal environment, while the hepatic barrier is a vital structure that can protect liver function and prevent endotoxin and virus from entering the liver to damage hepatocytes. Both the two barrier structures are most vulnerable to damage after partial liver transplantation due to the occurrence of postoperative 'small-for-size graft syndrome'. The pathogenesis of 'small-for-size graft syndrome' is associated with postoperative portal hypertension and hyperperfusion. How to effectively control the occurrence of 'small-for-size graft syndrome' and to protect the intestinal barrier and hepatic barrier postoperatively are key to the maintenance of intestinal and hepatic functions. The primary aim of this paper is to review the mechanisms underlying the development of injury of the hepatic barrier and intestinal barrier in patients with small-for-size graft syndrome after partial liver transplantation and to propose the corresponding protective measures.

Chemical composition of hepatic lipids mediates reperfusion injury of the macrosteatotic mouse liver through thromboxane A(2)

BACKGROUND & AIMS

Chemical composition of hepatic lipids is an evolving player in steatotic liver ischemia/reperfusion (I/R) injury. Thromboxane A(2) (TXA(2)) is a vasoactive pro-inflammatory lipid mediator derived from arachidonic acid (AA), an omega-6 fatty acid (Ω-6 FA). Reduced tolerance of the macrosteatotic liver to I/R may be related to increased TXA(2) synthesis due to the predominance of Ω-6 FAs.

METHODS

TXA(2) levels elicited by I/R in ob/ob and wild type mice were assessed by ELISA. Ob/ob mice were fed Ω-3 FAs enriched diet to reduce hepatic synthesis of AA and TXA(2) or treated with selective TXA(2) receptor blocker before I/R.

RESULTS

I/R triggered significantly higher hepatic TXA(2) production in ob/ob than wild type animals. Compared with ob/ob mice on regular diet, Ω-3 FAs supplementation markedly reduced hepatic AA levels before ischemia and consistently blunted hepatic TXA(2) synthesis after reperfusion. Sinusoidal perfusion and hepatocellular damage were significantly ameliorated despite downregulation of heme oxygenase-1. Hepatic transcript and protein levels of IL-1β and neutrophil recruitment were significantly diminished after reperfusion. Moreover, TXA(2) receptor blockage conferred similar protection without modification of the histological pattern of steatosis. A stronger protection was achieved in the steatotic compared with lean animals.

CONCLUSIONS

Enhanced I/R injury in the macrosteatotic liver is explained, at least partially, by TXA(2) mediated microcirculatory failure rather than size-related mechanical compression of the sinusoids by lipid droplets. TXA(2) blockage may be a simple strategy to include steatotic organs and overcome the shortage of donor organs for liver transplantation.

Comparison of 5 intravenous lipid emulsions and their effects on hepatic steatosis in a murine model

BACKGROUND

Plant-based intravenous lipid emulsions have been shown to contribute to parenteral nutrition-associated liver disease (PNALD). There is mounting evidence that fish oil-based emulsions may prevent this liver injury. This study compares 5 emulsions with different fat compositions and their effect on hepatic steatosis, one of the first hits in PNALD.

METHODS

C57BL/6J mice were placed on a fat-free diet and randomized into 5 equal groups. Each group received one of the commercially available intravenous lipid emulsions (Intralipid [Baxter/Fresenius Kabi, Deerfield, Ill], Liposyn II [Hospira Inc, Lake Forest, Ill], ClinOleic [Baxter/Clintec Parenteral SA, Cedex, France], SMOFlipid [Fresenius Kabi, Bad Homburg, Germany], or Omegaven [Fresenius Kabi Deutschland GmbH]) or normal saline. Liver enzymes, degree of steatosis, and fatty acid compositions were analyzed after 19 days.

RESULTS

Intralipid, Liposyn II, ClinOleic, and SMOFlipid groups all demonstrated moderate steatosis with hepatic fat contents of 17.4%, 21.9%, 22.5%, and 12.6%, respectively. Omegaven mice, however, had normal livers. Saline control mice developed biochemical evidence of essential fatty acid deficiency (EFAD). Lipid supplementation with Intralipid, Liposyn II, and Omegaven prevented the onset of biochemical EFAD, whereas administration of ClinOleic and SMOFlipid did not.

CONCLUSION

The fish oil-based lipid emulsion Omegaven prevented hepatic steatosis and EFAD in this murine model. ω-3 fatty acids may be efficacious in preventing PNALD and should be explored in the development of novel lipid emulsions.

Microvillous inclusion disease: how to improve the prognosis of a severe congenital enterocyte disorder

BACKGROUND AND OBJECTIVE

Microvillous inclusion disease (MVID) is a rare congenital enterocyte disorder causing severe diarrhea and intestinal failure. The objective of this study was to analyze clinical evolution and the most frequent complications of MVID in children receiving parenteral nutrition (PN) and after small-bowel transplantation (SBTx) with the aim to improve treatment strategies and prognosis.

PATIENTS AND METHODS

From 1995 to 2009, 24 patients (16 boys, median follow-up 4.7 years, range: from birth to 23.5 years) with MVID were admitted to our unit. The recorded parameters included growth, neurological development, liver and renal functions, bone disease, and outcome.

RESULTS

Almost half of the children were from consanguineous families from the Mediterranean area. All of the patients completely depended on PN. Four children died of PN complications before 4 years of age. Before or without SBTx, growth failure was common (mean height -2.5 standard deviations [SD]), as was developmental delay (12/24), liver (20/22 with fibrosis) or kidney disease (3/23 with moderate renal insufficiency), and osteoporosis (6/24). Thirteen children underwent SBTx (9 isolated, 4 combined with liver Tx) at a median age of 3.5 years. Follow-up after SBTx was 0.4 to 14 years. Patient survival rates were 63% without SBTx and 77% with SBTx. After SBTx, 4 children experienced catch-up growth.

CONCLUSIONS

PN in MVID is difficult to manage and requires expertise. Despite improved results in expert centers, the risk of death or irreversible sequelae is higher with PN than after Tx. SBTx, despite being complicated, remains the only hope to improve the quality of life and long-term prognosis of these children.

Omega-3 polyunsaturated acids and cardiovascular disease: notable ethnic differences or unfulfilled promise?

The consumption of long chain omega-3 polyunsaturated acids (PUFA) is considered to protect against cardiovascular disease and promote longevity following a heart attack. Historically, research in this area was fuelled by compelling reports of the cardiovascular benefits of omega-3 PUFA in select populations and cultures. More recent studies, in wider populations, suggest discordant findings: differences that are difficult to reconcile as the mechanism of action of omega-3 PUFA are poorly understood. As such, the use of this 'natural treatment' for cardiovascular disease is increasingly controversial, and potentially one of unfulfilled promise. To what extent does ethnicity influence the impact that omega-3 PUFA have on cardiovascular disease and its associated complications? We were interested to review the benefits of omega-3 PUFA in the management of cardiovascular risk amongst diverse ethnic groups. Using a systematic review of literature relating to omega-3 PUFA and cardiovascular disease, we found ethnicity to be a factor that accounts for inconsistency between studies. Some of the effects of omega-3 PUFA are limited to cultures with a very high omega-3 intake, and in turn, ethnicity moderates the efficiency with which PUFA are derived from the diet. Moreover, omega-3 PUFA are an important health care intervention in the current climate of globalization, where supplementation is likely to give protection to cultural groups undergoing dietary transition. Future epidemiological research into the efficacy of omega-3 PUFA in cardiovascular disease should consider the influence of ethnicity.

Metabolic syndrome and liver transplantation: a review and guide to management

Metabolic syndrome is common among liver transplant recipients before and after transplantation. The components of metabolic syndrome are often exacerbated in the post-transplant period by transplant specific factors, such as immunosuppression, and are strong predictors of patient morbidity and mortality. Many aspects of the metabolic syndrome are modifiable. Early recognition, prevention and treatment of post-transplant hypertension, obesity, dyslipidemia and diabetes may impact long-term post-transplant survival. Further study into the prevention and management of these issues in the transplant patient are needed.

The importance of fatty liver disease in clinical practice

The worldwide obesity epidemic over the last 20 years has led to a dramatic increase in the prevalence of non-alcoholic fatty liver disease, the hepatic manifestation of the metabolic syndrome. Estimates of prevalence vary depending on the population studied and the methods used to assess hepatic fat content, but are commonly quoted as between 10 and 30% of the adults in the Western hemisphere. Fatty liver develops when fatty acid uptake and synthesis in the liver exceeds fatty acid oxidation and export as TAG. Studies of pathogenesis point to insulin resistance, lipotoxicity, oxidative stress and chronic inflammation being central to the development and progression of the disease. A proportion of individuals with fatty liver develop progressive disease, though large prospective longitudinal studies are lacking. Nevertheless, fatty liver is associated with increased all-cause and liver-related mortality compared with the general population. Management of fatty liver centres around lifestyle and dietary measures to induce controlled and sustained weight loss. Management of cardiovascular risk factors aims to reduce mortality, while certain dietary interventions have been shown to reduce steatosis and inflammation. Specific pharmacological treatments also show promise, but their use is not widespread. A multi-system and multi-disciplinary approach to the management of this disorder is proposed.

Effects of a 1-year dietary intervention with n-3 polyunsaturated fatty acid-enriched olive oil on non-alcoholic fatty liver disease patients: a preliminary study

BACKGROUND AND AIMS

Non-alcoholic fatty liver disease (NAFLD) is a worldwide diffuse condition due to alimentary, environment and genetic factors. The aim of our preliminary study was to evaluate the effectiveness of long-term consumption of food enriched with n-3 polyunsaturated fatty acids (PUFA) in patients with NAFLD.

METHODS

Eleven patients were enrolled; six (four males, two females) were planned for oral administration of 6.5 ml olive oil enriched with n-3 PUFA for 12 months, while five (four males, one female) were used as controls.

RESULTS

Consumption of olive oil enriched with n-3 PUFA demonstrated a significant improvement of liver echo-texture and of the Doppler Perfusion Index after 12 months (after: 0.19 ± 0.02 vs. pre: 0.15 ± 0.03; P < 0.05), whereas no significant changes were seen at the end of follow-up in controls. Moreover, patients who consumed the olive oil enriched with n-3 PUFA showed a significant amelioration of liver enzymes, and of triglycerides (post: 132.8 ± 63.7 vs. pre: 164.5 ± 85.5 mg/dl; P = 0.04) in a general linear model adjusted for age and gender. Interestingly, patients reported to have a significant increase of adiponectin levels (post: 1,487.9 ± 96.7 vs. pre: 1,143 ± 24.8 μg/ml; P = 0.04).

CONCLUSION

The results of this preliminary study showed that long-term consumption of olive oil enriched with n-3 PUFA in patients with NAFLD is able to decrease circulating liver enzymes and triglycerides, with a significant improvement of adiponectin levels.

Parenteral fish oil as monotherapy prevents essential fatty acid deficiency in parenteral nutrition-dependent patients

OBJECTIVE

The use of fish oil-based emulsions as the sole source of fat for patients receiving parenteral nutrition (PN) has raised concerns for the development of essential fatty acid deficiency (EFAD), hindering its adoption into clinical practice. The purpose of the present study was to examine fatty acid profiles of patients receiving no enteral energy, while completely dependent on PN and an intravenous fish oil-based lipid emulsion, for onset of EFAD and maintenance of growth.

PATIENTS AND METHODS

Prospectively collected data from 10 patients were reviewed for evidence of EFAD, defined as a triene:tetraene ratio >0.2. Gestational age-adjusted z scores for length, growth, and head circumference at baseline were compared with the corresponding z scores at time of censoring. All of the patients received PN with a fish oil-based lipid emulsion at 1 g . kg . day as the sole source of fat energy for at least 1 month. The fish oil monotherapy was used under a compassionate use protocol.

RESULTS

Median gestational age at the time of birth was 35 weeks, and median age at the start of treatment was 3.5 months. After a median time of 3.8 months on exclusive PN and fish oil-based lipid emulsion, none of the patients developed biochemical or clinical evidence of EFAD. z scores were not statistically different, indicating no growth impairment. Median direct bilirubin levels improved in 9 patients from 6.8 to 0.9 mg/dL (P = 0.009).

CONCLUSIONS

: When dosed appropriately, fish oil-based lipid emulsions contain sufficient amounts of essential fatty acids to prevent EFAD and sustain growth in patients who are completely dependent on PN.

Growth factor modulation of hepatic inflammation: a novel approach to the management of total parenteral nutrition-associated liver disease

PURPOSE

Dependence on total parenteral nutrition in intestinal failure or short bowel syndrome patients can lead to many complications. The most significant complication is progressive liver injury leading to liver failure. This study assesses the potential of hepatocyte growth factor (HGF) in modulating the hepatic response in a rat cholestatic liver injury model.

METHODS

Female Sprague-Dawley rats were divided into 3 groups: control (n = 5), chronic liver injury (alpha-naphtylisocyocyanate [ANIT] every 3.5 days at 75 mg/kg; n = 5), and chronic liver injury plus HGF (ANIT + HGF at 250 microg kg(-1) d(-1); n = 5). The rats initially underwent massive (80%) small bowel resections. Seven days later, they were given intraperitoneal injections of saline (control) or ANIT and implantation of an osmotic minipump for continuous intravenous saline or HGF. Intraperitoneal saline or ANIT injections were subsequently administered every 3.5 days to create a chronic cholestatic model. After 14 days, the animals were euthanized, and liver biopsies were obtained. The liver biopsies were evaluated by histology, immunofluorescence staining for interleukin-6 and tumor necrosis factor alpha, and assessment of apoptosis by terminal dUTP-transferase-mediated nick end labeling (TUNEL) technique.

RESULTS

In this chronic liver injury model, HGF did not effect the grade of inflammation. However, HGF did induce retention of the ductal structures and avoided ductal proliferation, damage, and evidence of primary sclerosing cholangitis (P < .05). Hepatocyte growth factor induced less interleukin-6 (P < .011) and tumor necrosis factor alpha (P < .01) expression. Apoptotic activity was also significantly less in the HGF group (P < .01).

CONCLUSION

Hepatocyte growth factor preserved the hepatic ductal system, modulated the hepatic inflammatory response, and reduced the apoptotic index in this chronic cholestatic liver injury model. It may diminish or prevent liver damage in patients with total parenteral nutrition-induced liver injury.

Impact of fish oil-based lipid emulsion on serum triglyceride, bilirubin, and albumin levels in children with parenteral nutrition-associated liver disease

Parenteral nutrition is known to cause liver injury in babies. The aim of this study is to investigate the effects of different lipid emulsions on parenteral nutrition-associated cholestasis in infants. In addition, there may be a relationship between the lipid emulsion and triglyceride levels. Furthermore, triglyceride levels may correlate with direct bilirubin and albumin, as markers of liver impairment and nutritional status. Patients with parenteral nutrition-associated cholestasis who were treated with a fish oil-based lipid emulsion (n = 18) were prospectively followed for triglyceride, direct bilirubin, and albumin levels and compared with patients who were maintained on a soy-based lipid emulsion (n = 59). Triglyceride levels decreased in the fish oil cohort from a mean of 140 mg/dL at wk 0 to 40 mg/dL at wk 20 but remained unchanged at approximately 140 mg/dL in the soybean cohort. Triglyceride levels of patients treated with fish oil declined over time, while those receiving soybean oil did not. Also, changes in triglyceride levels over time were directly correlated with direct bilirubin and inversely related to albumin levels. These findings may indicate an added benefit of reduced triglyceride levels for patients treated with fish oil and this effect coincides with markers for improved liver function and nutritional status.

Pharmacologic therapy of non-alcoholic steatohepatitis

Specific therapy for non-alcoholic steatohepatitis (NASH) is needed because of the potential severity of this liver disease. NASH is a recognized cause of cryptogenic cirrhosis and, increasingly, of hepatocellular carcinoma. Therefore, there is an unmet medical need for the therapy of NASH. This article discusses this therapy, with particular emphasis on pharmacologic therapy.

Is liver fat detrimental to vessels?: intersections in the pathogenesis of NAFLD and atherosclerosis

NAFLD (non-alcoholic fatty liver disease) encompasses the spectrum of fatty liver disease in insulin-resistant individuals who often display T2DM (Type 2 diabetes mellitus) and obesity. The present review highlights the pathophysiological basis and clinical evidence for a possible causal linkage between NAFLD and CVD (cardiovascular disease). The role of traditional and non-traditional CVD risk factors in the pathophysiology of NAFLD is considered in the first part of the review, with the basic science shared by atherogenesis and hepatic steatogenesis discussed in depth in the second part. In conclusion, NAFLD is not an innocent bystander, but a major player in the development and progression of CVD. NAFLD and CVD also share similar molecular mechanisms and targeted treatment strategies. On the research side, studies should focus on interventions aimed at restoring energy homoeostasis in lipotoxic tissues and at improving hepatic (micro)vascular blood supply.

Effects of n-3 polyunsaturated fatty acids in subjects with nonalcoholic fatty liver disease

BACKGROUND

Long-chain polyunsaturated fatty acid omega-3 levels are decreased in the hepatic tissue of patients with nonalcoholic fatty liver disease. Polyunsaturated fatty acids are negative regulators of hepatic lipogenesis and attenuate the inflammatory response in mice.

AIM

To investigate whether polyunsaturated fatty acid may be effective in the treatment of nonalcoholic fatty liver disease.

METHODS

Forty patients with nonalcoholic fatty liver disease were randomized into two groups for treatment of 6 months duration. Group DP (n=20) received an AHA recommended diet and polyunsaturated fatty acid 2g/day; Group D (n=20) received only the AHA regular diet. Outcome measurements were fatty liver assessed by abdominal ultrasound, liver aminotransferase and tumour necrosis factor-alpha serum levels, and insulin resistance assessed by HOMA(IR).

RESULTS

After 6 months of treatment, the DP group displayed a decrease in alanine aminotransferase levels (p<0.01), as well as in triglyceride levels (p<0.01), serum tumour necrosis factor-alpha levels (p<0.05) and in HOMA(IR) (p<0.05). In the D group, no significant modification was observed. In the DP group, complete fatty liver regression was observed in 33.4% of the patients, and an overall reduction in 50%. In contrast, no patient achieved complete regression in the D group, whereas some amount of reduction occurred in 27.7% of the patients; the remaining 72.2% did not change.

CONCLUSION

Our results indicate that alanine aminotransferase, triglyceride and serum tumour necrosis factor-alpha levels, as well as fatty liver improved after polyunsaturated fatty acid administration.

Lysosomal leakage and lack of adaptation of hepatoprotective enzyme contribute to enhanced susceptibility to ethanol-induced liver injury in female rats

BACKGROUND

Women exhibit greater liver damage than men after chronic alcohol consumption. Similar findings are reported in animal models. Here, we determined whether differential liver injury occurred in male and female rats after feeding these animals liquid diets containing either ethanol or isocaloric dextrose with fish oil as the sole source of lipid.

METHODS

Control and ethanol liquid diets containing fish oil were pair-fed to male and female rats for 8 weeks. Liver damage was evaluated by triglyceride accumulation, lipid peroxide formation, serum transaminases, histological evaluation, and the activities of selected lysosomal and hepatoprotective enzymes.

RESULTS

Fatty liver was detected after ethanol feeding in both genders, but in female rats, triglyceride levels were 60% higher, lipid peroxides were 2-fold higher, and inflammatory cells were more evident than in males. A 2-fold elevation of cathepsin B in hepatic cytosol fractions, indicating lysosomal leakage, was detected in ethanol-fed female rats but no such elevation was observed in males. The basal activity of the hepatoprotective enzyme, betaine-homocysteine methyltransferase was 4-fold higher in livers of control male rats than females, and the enzyme activity was further elevated in ethanol-fed male rats but not in females.

CONCLUSIONS

Thus, female rats given ethanol in a diet containing fish oil exhibited more severe liver damage than males. We propose that this difference results, in part, from a greater tendency by females to accumulate hepatic fat, thereby enhancing the potential for oxidative stress, which in turn leads to hepatic inflammation. In addition, our findings indicate that female rats have a higher susceptibility to liver damage because of a reduced capacity for hepatoprotection.

Omega 3 - Omega 6: What is right for the liver?

Linoleic and alpha-linolenic acids are the fatty acids designated as "essential" since they are not synthesized by mammalian cells and must be provided in the diet. The recent dietary shift towards the consumption of n-6 (omega-6) at the expense of n-3 (omega-3) polyunsaturated fatty acids (PUFAs) is thought to be a primary cause of many diseases related to the Western diet. The body converts linoleic acid to arachidonic acid and derives eicosapentaenoic acid from alpha-linolenic acid. Ideally the effects of these fatty acids and their eicosanoid derivatives are tailored to the specific biological needs of the body. The balance between n-3 and n-6 PUFAs is essential for metabolism and maintenance of the functions of both classes. The availability of n-3 long chain PUFAs plays a major role in regulating both fat accumulation and its elimination by the liver. Derangement of hepatic n-6:n-3 PUFA ratio impacts on the histological pattern of fatty liver through modulation of the amount of intrahepatic lipids. Moreover, the influence of PUFAs and their eicosanoid products on hepatic microcirculation and ischemia/reperfusion injury has been demonstrated in many studies. This concise review article will focus on the role of PUFAs and eicosanoids in hepatic steatosis, microcirculation and ischemia/reperfusion injury.