Splanchnic haemodynamics in non-alcoholic fatty liver disease: effect of a dietary/pharmacological treatment. A pilot study

Effect of Weight Loss Medications on Hepatic Steatosis and Steatohepatitis: A Systematic Review

Non-alcoholic fatty liver disease (NAFLD) is a common comorbidity in individuals with obesity. Although multiple pharmacotherapeutics are in development, currently there are limited strategies specifically targeting NAFLD. This systematic review summarizes the existing literature on hepatic effects of medications used for weight loss. Glucagon-like peptide 1 (GLP-1) agonists are the best-studied in this regard, and evidence consistently demonstrates reduction in liver fat content, sometimes accompanied by improvements in histological features of steatohepatitis and reductions in serum markers of hepatic injury such as alanine aminotransferase (ALT). It remains unclear whether these benefits are independent of the weight loss caused by these agents. Literature is limited regarding effects of orlistat, but a small number of reports suggest that orlistat reduces liver fat content and improves histologic features of NASH, benefits which may also be driven primarily by weight loss. A sizeable body of literature on hepatic effects of metformin yields mixed results, with a probability of modest benefit, but no consistent signal for strong benefit. There are insufficient data on hepatic effects of topiramate, phentermine, naltrexone, bupropion, and lorcaserin. Finally, a few studies to date suggest that sodium-glucose co-transporter-2 (SGLT2) inhibitors may reduce liver fat content and cause modest reductions in ALT, but further study is needed to better characterize these effects. Based on available data, GLP-1 agonists have the strongest evidence base demonstrating beneficial effects on NAFLD, but it is not clear if any weight loss medication has effects on NAFLD superior to those of nutritional modification and exercise alone.

Systematic review and meta-analysis of controlled intervention studies on the effectiveness of long-chain omega-3 fatty acids in patients with nonalcoholic fatty liver disease

Context

Treatment options for nonalcoholic fatty liver disease (NAFLD) are needed.

Objective

The aim of this review was to systematically assess the effects of omega-3 long-chain polyunsaturated fatty acids (n-3 LC-PUFAs), particularly eicosapentaenoic acid and docosahexaenoic acid, on liver-related and metabolic outcomes in adult and pediatric patients with NAFLD.

Data Sources

The online information service ProQuest Dialog was used to search 8 literature databases.

Study Selection

Controlled intervention studies in which the independent effects of n-3 LC-PUFAs could be isolated were eligible for inclusion.

Data Extraction

The 18 unique studies that met the criteria for inclusion were divided into 2 sets, and data transcriptions and study quality assessments were conducted in duplicate. Each effect size was expressed as the weighted mean difference and 95%CI, using a random-effects model and the inverse of the variance as a weighting factor.

Results

Based on the meta-analyses, supplementation with n-3 LC-PUFAs resulted in statistically significant improvements in 6 of 13 metabolic risk factors, in levels of 2 of 3 liver enzymes, in liver fat content (assessed via magnetic resonance imaging/spectroscopy), and in steatosis score (assessed via ultrasonography). Histological measures of disease [which were assessed only in patients with nonalcoholic steatohepatitis (NASH)] were unaffected by n-3 LC-PUFA supplementation.

Conclusions

Omega-3 LC-PUFAs are useful in the dietary management of patients with NAFLD. Additional trials are needed to better understand the effects of n-3 LC-PUFAs on histological outcomes in patients with NASH.

Systematic Review Registration

PROSPERO CRD42017055951.

Laboratory Tests, Liver Vessels Color Doppler Sonography, and FibroScan Findings in Patients with Nonalcoholic Fatty Liver Disease: An Observation Study

Objective

Determination of the amount of parenchymal damage in nonalcoholic fatty liver disease (NAFLD) is crucial to choose the best treatment and management.

Aim

Here, the associations between laboratory data and severity of steatosis and fibrosis plus hepatic vessel Doppler indices in NAFLD patients were investigated.

Patients and Methods

Fifty patients (20 males and 30 females) with NAFLD criteria were enrolled. Fatty liver was graded by sonography (SGFL) and FibroScan (FGFL). In addition, liver fibrosis was graded through FGLF. Damages to the portal, hepatic, and splenic veins were evaluated by color Doppler/dopplex. Serum liver enzymes and C-reactive protein (CRP) were also measured.

Results

Significant association existed between SGFL and FGFL (P = 0.006). Portal vein pulsatility index (PI) and phasicity plus the triphasic and monophasic pattern of hepatic veins significantly associated with fatty liver grade evaluated by sonography. Splenic vein Peak systolic velocity and PI showed significant association with FGFL. Eventually, elevated liver enzymes and CRP significantly correlated with FGLF.

Conclusion

We found that the severity of fatty liver is correlated with hepatic and portal veins damages; however, the degree of parenchymal fibrosis was independent to these indices and can be directly evaluated by FGFL. In addition, elevated liver enzymes and CRP correlated with the degree of fibrosis.

Sonographic Evaluation of Liver Hemodynamic Indices in Overweight and Obese Dogs

Background

Hepatic circulatory disturbances have been associated with obesity and fatty liver in humans. In the veterinary literature, however, there is limited information regarding the effects of different body condition scores (BCS) on liver hemodynamic indices in dogs.

Objectives

To investigate the influence of BCS on liver hemodynamic indices.

Animals

Fifty‐three client‐owned dogs of various breeds were included.

Methods

Prospective observational study. Dogs were divided into 3 BCS groups using a 5‐point scale: G1 – 12 ideal dogs, G2 – 21 overweight dogs, G3 – 20 obese dogs. Mean portal velocity (MPV), portal blood flow volume (PBFV), portal congestion index (PCI), hepatic artery resistivity index (HARI), and hepatic vein (HV) spectral wave were obtained by pulsed Doppler sonography. Alkaline phosphatase (ALP), gamma‐glutamyl transferase (GGT), and alanine aminotransferase (ALT) activities were determined. Liver enzymes activities and liver hemodynamic indices were compared among groups.

Results

Obese dogs had lower MPV, higher percentage of abnormal hepatic vein spectral wave and higher median ALP activity than did ideal dogs (P < 0.05). Overweight and obese dogs had lower PBFV than ideal dogs (P < 0.01). Overweight dogs had higher median GGT activity than ideal dogs (P < 0.05). No difference was observed for PCI, HARI and median ALT activity among the groups.

Conclusions and Clinical Importance

Obesity was associated with changes in portal vein indices and in HV spectral wave. These changes were accompanied by significant differences in some liver enzymes activities and could be a sign of early liver disease.

Cymene and Metformin treatment effect on biochemical parameters of male NMRI mice fed with high fat diet

Background

The increasing prevalence of obesity is considered a serious global health threat. Mainly due to change of diet and reduced physical activity, obesity is an important risk factor for chronic diseases. A higher level of cytokines and a general inflammatory state has also been associated with this condition. With this regard, potential anti-obesity compounds with anti-inflammatory properties could be beneficial in better control of the disease. p-Cymene is a natural aromatic compound that has been shown to have anti-inflammatory properties, while the antidiabetic drug metformin has been observed to be effective as an aid for weight loss. In this study, the effect of these comounds was compared in a high fat diet treated mice model.

Methods

48 adult NMRI mice were randomly divided into six groups: control group receiving a normal diet, high fat diet (HFD) fed control group, sham group receiving HFD and sunflower seed oil, Experimental group1 (E1) receiving HFD and 20 mg/kg metformin, Experimental group2 (E2) receiving 20 mg/kg metformin and 20 mg/kg p-cymene, Experimental group3 (E3) receiving 20 mg/kg p-cymene. Compounds were administered by intragastric gavage for 45 days.

Results

Non-fasting glucose serum levels, ALT, and ALP of E2 and E3 decreased significantly compared to HFD control group. In the E3 group, AST levels decrease was also significant. In E1, non-fasting glucose and TG serum levels decreased significantly compared to HFD control group. Histological observations on liver tissue showed an increase of lipid droplets in the HFD control group compared with the normal group, while upon treatment with the compounds, lipid droplets decreased and the cells appeared to be more ordered.

Conclusion

p-Cymene has a potential to ameliorate biochemical parameters in high fat diet treated mice, and its concurrent use with metformin was effective.

The Doppler ultrasonographic evaluation of hemodynamic changes in hepatic vascular structures in patients with hepatosteatosis

Background

The hemodynamic changes in hepatic vascular structures of hepatosteatosis patients were examined using Doppler ultrasonography.

Material/Methods

Ninety hepatosteatosis patients, classified as mild, moderate or severe, and 30 healthy volunteers were included in this 120-person study. The height, weight, liver size, blood lipids and blood liver function tests of the subjects were measured. Those values were compared in the patient and control groups. In the patient and control groups, color duplex Doppler ultrasonography was used to examine portal vein peak velocity, portal vein flow volume, hepatic artery resistive index (RI), hepatic artery pulsatility index (PI) and hepatic artery flow volume.

Results

Similarly to the degree of hepatosteatosis, increases in body mass index, liver size, liver enzyme levels and blood lipid levels were statistically significant (p<0.05). While the difference in portal vein peak velocity in the hepatosteatosis and control groups was not statistically significant, there was an increasing reduction in the degree of steatosis (p>0.05). As the degree of hepatosteatosis increased, there was a reduction in hepatic artery flow volume, portal vein flow volume and total flow volume that was not statistically significant. In the mild hepatosteatosis group, hepatic artery RI and PI values were statistically significantly lower than in the other groups (p<0.05). In the severe hepatosteatosis group, although the hepatic artery RI and PI values were not statistically significant, there was a minimal increase compared to the other groups.

Conclusions

It is believed that those results were caused by a reduction in liver compliance and hepatic vascular compliance, in addition to resistance increase in vascular structures.

Ultrastructural study on tissue alterations caused by trypanosomatids in experimental murine infections

The ultrastructural study in different tissues of mice experimentally infected with isolates of Trypanosoma evansi, Trypanosoma cruzi, and Leishmania mexicana reveals changes in cardiac myocytes, skeletal muscle fibers, and hepatic, adrenal, kidney, and spleen cells. Some of these changes were cytoarchitectural and others consisted of necrosis. Alterations in the microvasculature were also found. The mononuclear cell infiltrate included neutrophils, eosinophils, and macrophages. This work shows that diverse mice tissues are important target for trypanosomatids.

The effect of pioglitazone and metformin on liver function tests, insulin resistance, and liver fat content in nonalcoholic Fatty liver disease: a randomized double blinded clinical trial

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is considered as the hepatic manifestation of insulin resistance (IR) syndrome. The effect of insulin sensitizers on liver function tests and metabolic indices in NAFLD patients is a matter of debate.

OBJECTIVES

The aim of study was to compare the effects of two different insulin sensitizers, pioglitazone, and metformin, on liver function tests (LFT), lipid profile, homeostasis model assessment-IR (HOMA-IR) index, and liver fat content (LFC) in NAFLD patients.

MATERIALS AND METHODS

This double blind clinical trial was performed on patients who were referred to a gastroenterology clinic with evidence of fatty liver in ultrasonography. After excluding other causes, participants with persistent elevated alanine aminotransferase (ALT) levels and "NAFLD liver fat score" greater than -0.64 were presumed to have NAFLD and were enrolled. They were randomly assigned to take metformin (1 g/day) or pioglitazone (30 mg/day) for four months. Fasting serum glucose (FSG), ALT, aspartate aminotransferase (AST), alkaline phosphatase (ALP), triglyceride, cholesterol (CHOL), high and low density lipoprotein (HDL, LDL), HOMA-IR, and LFC were checked at the baseline, two and four months post-treatment. LFC was measured by a validated formula.

RESULTS

Eighty patients (68 males) with mean age of 35.27 (± 7.98) were included. After 2 months, LFT was improved significantly in the pioglitazone group and did not change in the metformin group. After four months, both medications significantly decreased serum levels of LFT, FSG, CHOL, LDL, HOMA-IR, and LFC, and increased serum level of HDL. No statistically significant differences were seen between the two treatment groups with regard to the changes of laboratory parameters and LFC from baseline to four months post-treatment.

CONCLUSIONS

During the four months, the use of metformin (1 g/day) and pioglitazone (30 mg/day) were safe and might have equally affected LFT, HOMA-IR, lipid profile, and LFC in NAFLD patients.

Branched-chain amino acids alleviate nonalcoholic steatohepatitis in rats

Nonalcoholic steatohepatitis (NASH) is a prevalent disease in countries around the world. The branched-chain amino acids (BCAAs) leucine, isoleucine, and valine cannot be synthesized by the body and have been shown to promote muscle buildup; thus, it is logical to suggest that BCAAs can reduce fat deposition in the body. We used gonadectomized rats fed a high-fat diet to investigate the effects of BCAAs on lipid metabolism over an 8-week experimental period. Body composition, tissue histology, plasma lipid indices, and hormone levels were examined. We demonstrated that the body weights of rats were not significantly decreased but the mesenteric fat was significantly decreased (p < 0.05) in BCAA-treated rats. In addition, BCAAs decreased plasma lipid levels and fat deposition in the liver. At week 4, when the untreated rats displayed macrovesicular steatosis, BCAA-treated rats had only macrovesicular droplets in their hepatocytes. At week 8, when the untreated rat livers displayed profound inflammation and cirrhosis, BCAA-treated rat livers remained in the macrovesicular stage of steatosis. BCAAs induced higher blood glucose and plasma insulin levels (p < 0.05). BCAAs also improved liver blood flow by increasing mean arterial blood pressure and decreasing portal pressure, which helped delay the change in blood flow pattern to that of cirrhosis. BCAAs also induced the skeletal muscle to express higher levels of branched-chain α-keto acid dehydrogenase E1α, which indicates an enhanced metabolic capacity of BCAAs in muscle tissue. This study clearly demonstrates the effects of BCAAs on the amelioration of fat deposition in rats fed a high-fat diet.

Comparison of portal vein doppler indices and hepatic vein doppler waveform in patients with nonalcoholic fatty liver disease with healthy control

BACKGROUND

The purpose of the present study is to investigate the association of nonalcoholic fatty liver disease (NAFLD) with the doppler waveform pattern of hepatic veins and portal vein doppler indices.

OBJECTIVES

This assay may be useful in evaluating the natural course of NAFLD and monitor treatment efficacy on follow-up.

PATIENTS AND METHODS

This case control study was performed in 31 patients with NAFLD and 31 normal healthy adults who served as the control group. The patients presented with elevated liver enzymes levels (ALT/AST) and hyperechogenic livers in the B-mode ultrasonography examination. Eleven patients had a liver biopsy. After an 8-hour fast,B-mode and duplex doppler ultrasonography were performed, and the waveform patterns of the right hepatic vein, portal vein diameter, grade of fatty liver, portal vein pulsatility index (VPI), and mean flow velocity (MFV) were measured.

RESULTS

VPI and MFV values were 0.42 ± 0.92 and 17.27 ± 5.34 cm/second, respectively, in the control group and 0.25 ± 0.50 and 12.82 ± 4.32 cm/second in patients with NAFLD (P< 0.01). The frequency of abnormal hepatic vein doppler waveform patterns (biphasic or monophasic) was significantly higher in patients with NAFLD (55.2%) versus control subjects (3.2%) (P < 0.001). There was no correlation between the degree of fat infiltration and VPI (P = 0.714), MFV (P = 0.911), or hepatic vein waveform pattern (P = 0.197). We found no correlation between liver enzyme levels and MFV or VPI. However, the rate of abnormal hepatic vein was higher in patients with enzyme levels that exceeded twice the normal value (P = 0.05).

CONCLUSIONS

Patients with NAFLD have a high rate of abnormal hepatic vein doppler waveform patterns, and decreased VPI and MFV are suggestive of reduced vascular compliance in the liver. Elevated liver enzymes levels do not influence VPI or MFV, but patients with abnormal enzymes have higher rates of abnormal hepatic vein doppler waveform patterns.

Non-alcoholic steatohepatitis induces non-fibrosis-related portal hypertension associated with splanchnic vasodilation and signs of a hyperdynamic circulation in vitro and in vivo in a rat model

INTRODUCTION

Steatosis, without fibrosis, may lead to changes in liver blood flow, which are poorly understood, and to date have not been correlated to portal pressure and related haemodynamics.

AIMS

To study the temporal relation between progressive steatosis, portal pressure, systemic haemodynamics, vascular responsiveness, mesenteric and portal blood flow in methionine-choline-deficient diet (MCDD)-fed rats.

METHODS

Male Wistar rats fed the MCDD were examined at week (w) 0-1-2-3-4-5-6-7-8, respectively, including systemic haemodynamics and portal pressure. At w0-4-8, in vivo blood flow was measured in the portal vein and the superior mesenteric artery. Dose-response curves to phenylephrine (PE) were established in abdominal aortic rings.

RESULTS

Histology showed 100% steatosis from w3 on. Fibrosis was absent. Significant inflammation was nearly absent upon w4. Portal pressure slightly increased at w2, reached a maximum at w4 [9.4 +/- 0.3 vs 2.9 +/- 0.6 mmHg at w0 (P=0.003)] and remained stable upon w8. Mean arterial blood pressure (MABP) decreased from w2 on [98.7 +/- 5.7 mmHg on w4 compared with 123.8 +/- 1.8 on w0 (P=0.002)]. Portal flow increased from 1.85 +/- 0.11 to 3.07 +/- 0.44 ml/min/100 g on w0 and w8 respectively (P=0.039). Mesenteric artery flow increased from 3.40 +/- 0.26 to 4.56 +/- 0.30 ml/min/100 g on w0 and w8 respectively (P=0.043). Vascular responsiveness to PE gradually decreased from 138 +/- 3% on w0 to 110 +/- 5% on w4 (P=0.013).

CONCLUSION

Steatohepatitis induces significant portal hypertension (PHT) in the absence of fibrosis, associated with an increase in mesenteric arterial and portal venous flow, arterial hyporesponsiveness to vasoconstrictors and a decrease in MABP, indicating the presence of splanchnic vasodilation and hyperdynamic circulation. These alterations resemble those seen in cirrhotic PHT.

Nonalcoholic fatty liver disease (NAFLD) in nonobese patients with diabetes: Prevalence and relationships with hemodynamic alterations detected with Doppler sonography()

AIM

To evaluate the prevalence, severity, and hemodynamic features of nonalcoholic fatty liver disease (NAFLD) in nonobese diabetics.

METHODS

We studied 100 consecutive nonobese (body mass index [BMI] < 30) patients with type 1 (n = 17) or type 2 (n = 83) diabetes and no known causes of liver disease. Steatosis was diagnosed and graded with ultrasonography. Digital sonographic images of the liver and right kidney were analyzed with dedicated software (HDI-Lab), and the liver/kidney ratio of grey-scale intensity was calculated as an index of the severity of the steatosis. Severity scores ranging from 0 (none) to 5 (severe) were compared with sonographic and Doppler findings (right liver size, portal vein diameter and flow velocity, hepatic and splenic arterial pulsatility indices, hepatic-vein flow profile and A- and S-wave velocities).

RESULTS

The prevalence of steatosis was 24% in type I and 80% in type II diabetes (grade 1 in 17%, grade 2 in 34%, grade 3 in 33%, grade 4 in 9%, grade 5 in 7%). In patients with steatosis (especially those with grades 4-5 disease), hepatic volume was increased (p < 0.005). Portal vein diameter was increased in grade 5 steatosis. The hepatic artery pulsatility index was significantly increased, particularly in grades 4 and 5 (p < 0.0001); portal and A-wave velocities were significantly reduced in grades 3-5 (p < 0.001); and the hepatic vein flow profile was altered in 27% (biphasic: 20%, flat: 7%) patients with steatosis, although there was no correlation with severity.

CONCLUSIONS

NAFLD is very frequent in nonobese diabetics with type 2 but not type 1 disease, and it is associated with hepatomegaly and liver hemodynamic alterations only when it is severe.

Treatment of non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is common and may progress to cirrhosis and its complications. The pathogenesis of steatosis and cellular injury is thought to be related mostly to insulin resistance and oxidative stress. Therefore, management entails identification and treatment of metabolic risk factors, improving insulin sensitivity, and increasing antioxidant defences in the liver. Weight loss and exercise improve insulin sensitivity. Bariatric surgery may improve liver histology in patients with morbid obesity. Insulin sensitising drugs showed promise in pilot trials as have a number of hepatoprotective agents. Further randomised, well controlled trials are required to determine the efficacy of these drugs.

Nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease is emerging as the most common chronic liver condition in the Western world. It is associated with insulin resistance and frequently occurs with features of the metabolic syndrome. Disease presentation ranges from asymptomatic elevated liver enzyme levels to cirrhosis with complications of liver failure and hepatocellular carcinoma. Current treatment recommendations are limited to weight loss and exercise, although several promising medications are on the horizon. In this article we discuss the etiology, pathogenesis and diagnosis of nonalcoholic fatty liver disease as well as approaches to its management.