If steatosis is the atherosclerosis of the liver, are statins the "aspirin" for steatosis?

Statin Use and Reduced Hepatocellular Carcinoma Risk in Patients With Nonalcoholic Fatty Liver Disease

BACKGROUND & AIMS

Recent evidence suggests potential clinical benefits of statin in cancer chemoprevention and treatment. Nonalcoholic fatty liver disease (NAFLD) is expected to become the leading cause of hepatocellular carcinoma (HCC). We aimed to investigate the association between statin initiation and the risk of HCC among patients with NAFLD.

METHODS

In this study using the Optum de-identified Clinformatics database, Cox proportional hazards regression model was performed to determine the risk of HCC in statin initiators versus nonusers. We incorporated inverse probability of treatment weighting (IPTW) to minimize potential confounding.

RESULTS

Among 272,431 adults with NAFLD diagnosis, IPTW model shows that statin initiators had 53% less risk of developing HCC compared with nonusers (hazard ratio [HR], 0.47; 95% confidence interval, 0.36-0.60). In the subcohort with fibrosis-4 index data available, statin initiation was associated with 56% hazard reduction of developing HCC in NAFLD after adjusting for fibrosis-4 index score (HR, 0.44; 0.30-0.65). The association between statin initiation and lower risk of HCC development was observed for both lipophilic statin (HR, 0.49; 0.37-0.65) and hydrophilic statin (HR, 0.40; 0.21-0.76). Moreover, we observed greater hazards reduction as the dose and duration of statin use increased. NAFLD patients with more than 600 cumulative defined daily doses of statin had 70% reduction in hazards of developing HCC (HR, 0.30; 0.20-0.43).

CONCLUSIONS

Our study provides strong evidence for the association between statin initiation and reduced risk of HCC development in NAFLD patients. These findings imply that statin can be used as a protective medication for NAFLD patients to reduce the risk of HCC.

Non-alcoholic fatty liver disease and risk of cardiovascular disease

Non-alcoholic fatty liver disease (NAFLD) has become the leading cause of chronic liver diseases worldwide, causing considerable liver-related mortality and morbidity. During the past decade, it has also become increasingly evident that NAFLD is a multisystem disease that affects many extra-hepatic organ systems, including the heart and the vascular system. In this updated clinical review, we discuss the rapidly expanding body of clinical and epidemiological evidence that supports a strong association of NAFLD with cardiovascular diseases (CVDs) and other functional and structural myocardial abnormalities. We also discuss some recently published data that correlate NAFLD due to specific genetic polymorphisms with the risk of CVDs. Finally, we briefly examine the assessment tools for estimating the global CVD risk in patients with NAFLD as well as the conventional and the more innovative pharmacological approaches for the treatment of CVD risk in this group of patients.

Cardiovascular Disease and Myocardial Abnormalities in Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease in many developed countries, affecting an estimated 30 % of the adult population. In this updated clinical review, we summarize the current knowledge regarding the strong association between NAFLD and the risk of coronary heart disease (CHD) and other functional, structural, and arrhythmic cardiac complications (e.g., left ventricular dysfunction, heart valve diseases and atrial fibrillation). We also briefly discuss the putative biological mechanisms linking NAFLD with these important extra-hepatic complications. To date, a large body of evidence has suggested that NAFLD is not simply a marker of CHD and other functional, structural, and arrhythmic cardiac complications, but also may play a part in the development and progression of these cardiac complications. The clinical implication of these findings is that patients with NAFLD may benefit from more intensive surveillance and early treatment interventions aimed at decreasing the risk of CHD and other cardiac and arrhythmic complications.

Diagnosis and management of cardiovascular risk in nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is increasingly recognized as an important cardiovascular risk (CVR) factor. This is a narrative clinical review aimed at answering how diagnosis and management of CVR should be conducted in the individual patient with NAFLD. To this end, the authors performed an extensive search of the existing literature on PubMed (1993-2014) using pertinent keywords. To date, CVR among patients with NAFLD might be assessed with the Framingham risk score equation or other risk calculators, to be adapted to the true CVR in the specific population being assessed; however, the use of these CVR calculators needs to be validated by future studies in larger cohorts of NAFLD patients of various ethnic backgrounds in order to substantiate their clinical relevance as a foundation for the primary prevention of cardiovascular diseases in this group of patients. Early and aggressive drug treatment of CVR should be started in NAFLD patients with a history of cardiovascular events, established diabetes or who are at high (calculated) CVR. Whether such an aggressive pharmacological approach is also justified in patients with NAFLD, who are at intermediate or low CVR, remains debatable. Currently, there are no clinical trials showing that the treatment of NAFLD per se (either associated or unassociated with traditional CVR factors) will result in decreased risk of cardiovascular events. Accordingly, drug treatment should be better individualized, aiming at correcting all the coexisting cardio-metabolic risk factors of the individual patient with NAFLD. To this end, an overview of the lifestyle interventions and the available drugs is offered, emphasis being conveyed to statins and metformin, which promise to cover worrying complications of NAFLD such as the risk of developing hepatocellular carcinoma.

Nonalcoholic fatty liver disease and aging: Epidemiology to management

Nonalcoholic fatty liver disease (NAFLD) is common in the elderly, in whom it carries a more substantial burden of hepatic (nonalcoholic steatohepatitis, cirrhosis and hepatocellular carcinoma) and extra-hepatic manifestations and complications (cardiovascular disease, extrahepatic neoplasms) than in younger age groups. Therefore, proper identification and management of this condition is a major task for clinical geriatricians and geriatric hepatologists. In this paper, the epidemiology and pathophysiology of this condition are reviewed, and a full discussion of the link between NAFLD and the aspects that are peculiar to elderly individuals is provided; these aspects include frailty, multimorbidity, polypharmacy and dementia. The proper treatment strategy will have to consider the peculiarities of geriatric patients, so a multidisciplinary approach is mandatory. Non-pharmacological treatment (diet and physical exercise) has to be tailored individually considering the physical limitations of most elderly people and the need for an adequate caloric supply. Similarly, the choice of drug treatment must carefully balance the benefits and risks in terms of adverse events and pharmacological interactions in the common context of both multiple health conditions and polypharmacy. In conclusion, further epidemiological and pathophysiological insight is warranted. More accurate understanding of the molecular mechanisms of geriatric NAFLD will help in identifying the most appropriate diagnostic and therapeutic approach for individual elderly patients.

Simple steatosis is a more relevant source of serum inflammatory markers than omental adipose tissue

BACKGROUND AND AIMS

Serum inflammatory biomarkers are closely associated with the risk of cardiovascular disease. However, the major source of these biomarkers is not yet determined. Therefore, we aimed to assess whether simple steatosis or visceral adiposity was a more relevant predictor for serum inflammatory biomarkers.

METHODS

A double approach was used: i) clinical: 50 patients with biopsy-proven simple steatosis, 50 non-simple steatosis overweight patients, and 50 controls were explored for their serum biomarkers (high-sensitivity C-reactive protein, plasminogen activator inhibitor-1 activity, tumor necrosis factor α, and fibrinogen levels) and for visceral adiposity (measured by computed tomography); ii) experimental: using a rat simple steatosis model the effect of omentectomy on inflammatory biomarkers was investigated.

RESULTS

Serum inflammatory biomarkers were significantly higher in the simple steatosis group than in the overweight group. Using multivariate analysis, simple steatosis, visceral adiposity index and visceral adiposity were independently associated with inflammatory biomarkers. In particular, serum inflammatory biomarkers increased with the severity of liver histology (p<0.05), but no with visceral adipose tissue increase. In rats with simple steatosis, the omentectomy treatment was not associated with a decrease of serum inflammatory biomarkers in rats with simple steatosis.

CONCLUSIONS

Clinical and experimental data both indicate that simple steatosis may be more associated with inflammatory biomarkers than omental adipose tissue.

Hepatic function and the cardiometabolic syndrome

Despite skeletal muscle being considered by many as the source of insulin resistance, physiology tells us that the liver is a central and cardinal regulator of glucose homeostasis. This is sometimes underestimated because, in contrast with muscle, investigations of liver function are technically very difficult. Nevertheless, recent experimental and clinical research has demonstrated clearly that, due in part to its anatomic position, the liver is exquisitely sensitive to insulin and other hormonal and neural factors, either by direct intrahepatic mechanisms or indirectly by organ cross-talk with muscle or adipose tissue. Because the liver receives absorbed nutrients, these have a direct impact on liver function, whether via a caloric excess or via the nature of food components (eg, fructose, many lipids, and trans fatty acids). An emerging observation with a possibly great future is the increase in intestinal permeability observed as a consequence of high fat intake or bacterial modifications in microbiota, whereby substances normally not crossing the gut gain access to the liver, where inflammation, oxidative stress, and lipid accumulation leads to fatty liver, a situation observed very early in the development of diabetes. The visceral adipose tissue located nearby is another main source of inflammatory substances and oxidative stress, and also acts on hepatocytes and Kupffer cells, resulting in stimulation of macrophages. Liberation of these substances, in particular triglycerides and inflammation factors, into the circulation leads to ectopic fat deposition and vascular damage. Therefore, the liver is directly involved in the development of the prediabetic cardiometabolic syndrome. Treatments are mainly metformin, and possibly statins and vitamin D. A very promising avenue is treatment of the leaky gut, which appears increasingly to be an important causal factor in hepatic insulin resistance and steatosis.

Simvastatin ameliorates liver fibrosis via mediating nitric oxide synthase in rats with non-alcoholic steatohepatitis-related liver fibrosis

Background

Simvastatin exerts pleiotropic effects on cardiovascular system. However, its effect on non-alcoholic fatty liver disease, especially the liver fibrosis, remains obscure. We aimed to clarify the relationship between simvastatin and liver fibrosis both in vivo and in vitro.

Methods

A High-fat diet was given to establish rat models with non-alcoholic steatohepatitis (NASH)-related liver fibrosis and simvastatin (4mg·kg^-1·d^-1) was administrated intragastrically until hepatic histological findings confirmed the appearance of fibrosis. Human hepatic stellate cell (HSC) line lx-2 cells were cultured in an adipogenic differentiating mixture (ADM) and then were treated with transforming growth factorβ1 (TGF-β1), served as a positive control, simvastatin, TGF-β1 plus simvastatin, N_ω-nitro-L-arginine methyl ester hydrochloride (L-NAME, a inhibitor of nitric oxide synthase), and L-NAME plus simvastatin, respectively. The expressions of endothelial nitric oxide synthase (eNOS), inducible nitric oxide synthase (iNOS), and Collagen І as well as cellular α-smooth muscle actin (α-SMA) were measured by real-time reverse transcriptase-polymerase chain reaction (qRT-PCR) and Western blot in liver tissue and HSC.

Results

With the progress of NASH-related fibrosis, hepatic mRNA and protein expressions of iNOS, α-SMA, and Collagen І were increased while those of eNOS were decreased. Compared with model rats in 24^th week group, rats in simvastatin group had less expressions of iNOS, α-SMA, and Collagen І and more expressions of eNOS. In vitro, LX-2 cells acquired quiescent phenotype when cultured in ADM, and TGF-β1 could activate the quiescent HSC. Simvastatin inhibited LX-2 cells activation due to TGF-β1 or L-NAME by increasing the expression of eNOS and decreasing the expression of iNOS.

Conclusions

Simvastatin improves the prognosis of NASH-related fibrosis by increasing the expression of eNOS, decreasing the expression of iNOS, and inhibiting the activation of HSC.