Association of coronary artery calcification with liver fibrosis in Japanese patients with non-alcoholic fatty liver disease

Independent Associations of Aortic Calcification with Cirrhosis and Liver Related Mortality in Veterans with Chronic Liver Disease

INTRODUCTION

Abdominal aortic calcifications (AAC) are incidentally found on medical imaging and useful cardiovascular burden approximations. The Morphomic Aortic Calcification Score (MAC) leverages automated deep learning methods to quantify and score AACs. While associations of AAC and non-alcoholic fatty liver disease (NAFLD) have been described, relationships of AAC with other liver diseases and clinical outcome are sparse. This study's purpose was to evaluate AAC and liver-related death in a cohort of Veterans with chronic liver disease (CLD).

METHODS

We utilized the VISN 10 CLD cohort, a regional cohort of Veterans with the three forms of CLD: NAFLD, hepatitis C (HCV), alcohol-associated (ETOH), seen between 2008 and 2014, with abdominal CT scans (n = 3604). Associations between MAC and cirrhosis development, liver decompensation, liver-related death, and overall death were evaluated with Cox proportional hazard models.

RESULTS

The full cohort demonstrated strong associations of MAC and cirrhosis after adjustment: HR 2.13 (95% CI 1.63, 2.78), decompensation HR 2.19 (95% CI 1.60, 3.02), liver-related death HR 2.13 (95% CI 1.46, 3.11), and overall death HR 1.47 (95% CI 1.27, 1.71). These associations seemed to be driven by the non-NAFLD groups for decompensation and liver-related death [HR 2.80 (95% CI 1.52, 5.17; HR 2.34 (95% CI 1.14, 4.83), respectively].

DISCUSSION

MAC was strongly and independently associated with cirrhosis, liver decompensation, liver-related death, and overall death. Surprisingly, stratification results demonstrated comparable or stronger associations among those with non-NAFLD etiology. These findings suggest abdominal aortic calcification may predict liver disease severity and clinical outcomes in patients with CLD.

Non-alcoholic faty liver disease and liver fibrosis score have an independent relationship with the presence of mitral annular calcification

Non-alcoholic faty liver disease (NAFLD) and liver fibrosis score (FIB 4) are associated with increased mortality from cardiovascular causes. NAFLD and cardiac diseases are different manifestations of systemic metabolic syndrome. In this study, we aimed to reveal the relationship between NAFLD and FIB 4 liver fibrosis scores and mitral annular calcification (MAC). One hundred patients were included in the study. Blood samples and echocardiography measurements were obtained from each subject. The two groups were compared in terms of demographic and echocardiographic characteristics. Thirty-one men and 69 women with a mean age of 48.6 ± 13.1 years were included in the analysis. The patients were divided into two groups as those with MAC (n = 26) and those without (n = 74). The baseline demographic and laboratory data for the two groups were compared. In the group with MAC (+) age, serum creatinine levels, FIB4 and NAFLD Scores; HL, DM rates, angiotensin converting enzyme (ACE) inhibitor and statin usage rates were higher, with statistical significance. NAFLD and FIB 4 liver fibrosis scores have an independent relationship with MAC.

Association between liver fibrosis and thrombotic or bleeding events in acute coronary syndrome patients

BACKGROUND

The prognostic implication of liver fibrosis in acute coronary syndrome (ACS) patients are scarce. We sought to evaluate whether liver fibrosis scores (LFS) were associated with thrombotic or bleeding events in patients with acute coronary syndrome.

METHODS

We included 6386 ACS patients who underwent percutaneous coronary intervention (PCI). This study determined liver fibrosis with aspartate aminotransferase to platelet ratio index (APRI), aspartate aminotransferase to alanine aminotransferase ratio (AST/ALT ratio), Forns score, and nonalcoholic fatty liver disease fibrosis score (NFS). The primary endpoint was major adverse cardiac and cerebrovascular events (MACCE), a composite of all-cause mortality (ACM), myocardial infarction (MI), and ischemic stroke (IS).

RESULTS

During the follow-up, 259 (4.06%) MACCE and 190 (2.98%) bleeding events were recorded. As a continuous variable or a categorical variable stratified by the literature-based cutoff, LFS was positively associated with MACCE (p > 0.05) but not with bleeding events. Compared with subjects with low APRI scores, AST/ALT ratio scores, Forns scores, and NFS scores, subjects with high scores had a 1.57- to 3.73-fold increase risk of MACCE after adjustment (all p < 0.05). The positive relationship between LFS and MACCE was consistent in different subgroups.

CONCLUSIONS

In ACS patients, increased LFS predicted an elevated risk of thrombotic events but not bleeding. LFS may contribute to thrombotic risk stratification after ACS.

Fatty Liver as Potential Biomarker of Atherosclerotic Damage in Familial Combined Hyperlipidemia

Familial combined hyperlipidemia (FCH) is a very common inherited lipid disorder, characterized by a high risk of developing cardiovascular (CV) disease and metabolic complications, including insulin resistance (IR) and type 2 diabetes mellitus (T2DM). The prevalence of non-alcoholic fatty liver disease (NAFLD) is increased in FCH patients, especially in those with IR or T2DM. However, it is unknown how precociously metabolic and cardiovascular complications appear in FCH patients. We aimed to evaluate the prevalence of NAFLD and to assess CV risk in newly diagnosed insulin-sensitive FCH patients. From a database including 16,504 patients, 110 insulin-sensitive FCH patients were selected by general practitioners and referred to the Lipid Center. Lipid profile, fasting plasma glucose and insulin were determined by standard methods. Based on the results of the hospital screening, 96 patients were finally included (mean age 52.2 ± 9.8 years; 44 males, 52 females). All participants underwent carotid ultrasound to assess carotid intima media thickness (cIMT), presence or absence of plaque, and pulse wave velocity (PWV). Liver steatosis was assessed by both hepatic steatosis index (HSI) and abdomen ultrasound (US). Liver fibrosis was non-invasively assessed by transient elastography (TE) and by fibrosis 4 score (FIB-4) index. Carotid plaque was found in 44 out of 96 (45.8%) patients, liver steatosis was found in 68 out of 96 (70.8%) and in 41 out of 96 (42.7%) patients by US examination and HSI, respectively. Overall, 72 subjects (75%) were diagnosed with steatosis by either ultrasound or HSI, while 24 (25%) had steatosis excluded (steatosis excluded by both US and HSI). Patients with liver steatosis had a significantly higher body mass index (BMI) compared to those without (p < 0.05). Steatosis correlated with fasting insulin (p < 0.05), liver stiffness (p < 0.05), BMI (p < 0.001), and inversely with high-density lipoprotein cholesterol (p < 0.05). Fibrosis assessed by TE was significantly associated with BMI (p < 0.001) and cIMT (p < 0.05); fibrosis assessed by FIB-4 was significantly associated with sex (p < 0.05), cIMT (p < 0.05), and atherosclerotic plaque (p < 0.05). The presence of any grade of liver fibrosis was significantly associated with atherosclerotic plaque in the multivariable model, independent of alcohol habit, sex, HSI score, and liver stiffness by TE (OR 6.863, p < 0.001). In our cohort of newly diagnosed, untreated, insulin-sensitive FCH patients we found a high prevalence of liver steatosis. Indeed, the risk of atherosclerotic plaque was significantly increased in patients with liver fibrosis, suggesting a possible connection between liver disease and CV damage in dyslipidemic patients beyond the insulin resistance hypothesis.

Arterial Calcifications in Patients with Liver Cirrhosis Are Linked to Hepatic Deficiency of Pyrophosphate Production Restored by Liver Transplantation

Liver fibrosis is associated with arterial calcification (AC). Since the liver is a source of inorganic pyrophosphate (PPi), an anti-calcifying compound, we investigated the relationship between plasma PPi ([PPi]pl), liver fibrosis, liver function, AC, and the hepatic expression of genes regulating PPi homeostasis. To that aim, we compared [PPi]pl before liver transplantation (LT) and 3 months after LT. We also assessed the expression of four key regulators of PPi in liver tissues and established correlations between AC, and scores of liver fibrosis and liver failure in these patients. LT candidates with various liver diseases were included. AC scores were assessed in coronary arteries, abdominal aorta, and aortic valves. Liver fibrosis was evaluated on liver biopsies and from non-invasive tests (FIB-4 and APRI scores). Liver functions were assessed by measuring serum albumin, ALBI, MELD, and Pugh−Child scores. An enzymatic assay was used to dose [PPi]pl. A group of patients without liver alterations from a previous cohort provided a control group. Gene expression assays were performed with mRNA extracted from liver biopsies and compared between LT recipients and the control individuals. [PPi]pl negatively correlated with APRI (r = −0.57, p = 0.001, n = 29) and FIB-4 (r = −0.47, p = 0.006, n = 29) but not with interstitial fibrosis index from liver biopsies (r = 0.07, p = 0.40, n = 16). Serum albumin positively correlated with [PPi]pl (r = 0.71; p < 0.0001, n = 20). ALBI, MELD, and Pugh−Child scores correlated negatively with [PPi]pl (r = −0.60, p = 0.0005; r = −0.56, p = 0.002; r = −0.41, p = 0.02, respectively, with n = 20). Liver fibrosis assessed on liver biopsies by FIB-4 and by APRI positively correlated with coronary AC (r = 0.51, p = 0.02, n = 16; r = 0.58, p = 0.009, n = 20; r = 0.41, p = 0.04, n = 20, respectively) and with abdominal aorta AC (r = 0.50, p = 0.02, n = 16; r = 0.67, p = 0.002, n = 20; r = 0.61, p = 0.04, n = 20, respectively). FIB-4 also positively correlated with aortic valve calcification (r = 0.40, p = 0.046, n = 20). The key regulator genes of PPi production in liver were lower in patients undergoing liver transplantation as compared to controls. Three months after surgery, serum albumin levels were restored to physiological levels (40 [37−44] vs. 35 [30−40], p = 0.009) and [PPi]pl was normalized (1.40 [1.07−1.86] vs. 0.68 [0.53−0.80] µmol/L, p = 0.0005, n = 12). Liver failure and/or fibrosis correlated with AC in several arterial beds and were associated with low plasma PPi and dysregulation of key proteins involved in PPi homeostasis. Liver transplantation normalized these parameters.

MAFLD: Renovation of clinical practice and disease awareness of fatty liver

Recently, international expert panels have proposed a new definition of fatty liver: metabolic dysfunction-associated fatty liver disease (MAFLD). MAFLD is not just a simple renaming of non-alcoholic fatty liver disease (NAFLD). The unique feature of MAFLD is the inclusion of metabolic dysfunctions, which are high-risk factors for events. In addition, MAFLD is independent of alcohol intake and the co-existing causes of liver disease. This new concept of MAFLD may have a widespread impact on patients, medical doctors, medical staff, and various stakeholders regarding fatty liver. Thus, MAFLD may renovate clinical practice and disease awareness of fatty liver. In this review, we introduce the definition of and rationale for MAFLD. We further describe representative cases showing how the diagnostic processes differ between MAFLD and NAFLD. We also summarize recent studies comparing MAFLD with NAFLD and discuss the impact of MAFLD on clinical trials, Japanese populations, and disease awareness.

High fibrosis-4 index predicts the new onset of ischaemic heart disease during a 10-year period in a general population

Aims

The fibrosis-4 (FIB-4) index, calculated using age, platelet count, and levels of aspartate aminotransferase and alanine aminotransferase, is a non-invasive indicator for the detection of liver fibrosis. Advanced hepatic fibrosis is associated with morbidity and mortality in patients with non-alcoholic fatty liver disease. However, the relationship between liver fibrosis and the development of ischaemic heart disease (IHD) has not fully been addressed.

Methods and results

We investigated the association between the FIB-4 index and the new onset of IHD during a 10-year period in a general population of subjects who received annual health examinations (n = 28 990). After exclusion of subjects with missing data and those with a history of IHD at baseline, a total of 13 448 subjects (men/women: 8774/4674, mean age: 48 years) were included. During the 10-year period, 378 men (4.3%) and 77 women (1.6%) had a new onset of IHD. Multivariable Cox proportional hazard models with a restricted cubic spline showed that hazard risk for the development of IHD increased with a higher FIB-4 index at baseline after adjustment of age, sex, fatty liver (FL) determined by ultrasonography, estimated glomerular filtration rate, habits of current smoking and alcohol drinking, family history of IHD, and diagnosis of hypertension, diabetes mellitus and dyslipidaemia. When divided by FL, the FIB-4 index becomes an independent predictor for the development of IHD in subjects with FL but not in those without FL. The addition of the FIB-4 index to traditional risk factors for IHD significantly improved the discriminatory capability.

Conclusion

A high level of the FIB-4 index predicts the new onset of IHD during a 10-year period.

Association of Hepatic Steatosis With Major Adverse Cardiovascular Events, Independent of Coronary Artery Disease

BACKGROUND & AIMS

Hepatic steatosis has been associated with increased risk of major adverse cardiovascular events (MACE) but it is not clear whether steatosis is independently associated with risk of MACE. We investigated whether steatosis is associated with risk of MACE independently of the presence and extent of baseline coronary artery disease, assessed by comprehensive contrast-enhanced computed tomography angiography (CTA).

METHODS

We conducted a nested cohort study of 3756 subjects (mean age, 60.6 years; 48.4% men) who underwent coronary CTA at 193 sites in North America, from July 2010 through September 2013, as part of the PROMISE study, which included noninvasive cardiovascular analyses of symptomatic outpatients without coronary artery disease. Independent core laboratory readers measured hepatic and splenic attenuation, using non-contrast computed tomography images to identify steatosis, and evaluated coronary plaques and stenosis in coronary CTA images. We collected data on participants' cardiovascular risk factors, presence of metabolic syndrome, and body mass index. The primary endpoint was an adjudicated composite of MACE (death, myocardial infarction, or unstable angina) during a median follow-up time of 25 months.

RESULTS

Among the 959 subjects who had steatosis (25.5% of the cohort), 42 had MACE (4.4%), whereas among the 2797 subjects without steatosis, 73 had MACE (2.6%) (hazard ratio [HR] for MACE in subjects with steatosis, 1.69; 95% CI, 1.16-2.48; P = .006 for MACE in subjects with vs without steatosis). This association remained after adjustment for atherosclerotic cardiovascular disease risk scores, significant stenosis, and metabolic syndrome (adjusted HR, 1.72; 95% CI, 1.16-2.54; P = .007) or obesity (adjusted HR, 1.75; 95% CI, 1.19-2.59; P = .005). Steatosis remained independently associated with MACE after adjustment for all CTA measures of plaques and stenosis.

CONCLUSIONS

Hepatic steatosis is associated with MACE independently of other cardiovascular risk factors or extent of coronary artery disease. Strategies to reduce steatosis might reduce risk of MACE. ClinicalTrials.gov no: NCT01174550.

Interplay between Heart Disease and Metabolic Steatosis: A Contemporary Perspective

The liver-heart axis is a growing field of interest owing to rising evidence of complex bidirectional interplay between the two organs. Recent data suggest non-alcoholic fatty liver disease (NAFLD) has a significant, independent association with a wide spectrum of structural and functional cardiac diseases, and seems to worsen cardiovascular disease (CVD) prognosis. Conversely, the effect of cardiac disease on NAFLD is not well studied and data are mostly limited to cardiogenic liver disease. We believe it is important to further investigate the heart-liver relationship because of the tremendous global health and economic burden the two diseases pose, and the impact of such investigations on clinical decision making and management guidelines for both diseases. In this review, we summarize the current knowledge on NAFLD diagnosis, its systemic manifestations, and associations with CVD. More specifically, we review the pathophysiological mechanisms that govern the interplay between NAFLD and CVD and evaluate the relationship between different CVD treatments and NAFLD progression.

FIB-4 First in the Diagnostic Algorithm of Metabolic-Dysfunction-Associated Fatty Liver Disease in the Era of the Global Metabodemic

The prevalence of obesity or metabolic syndrome is increasing worldwide (globally metabodemic). Approximately 25% of the adult general population is suffering from nonalcoholic fatty liver disease (NAFLD), which has become a serious health problem. In 2020, global experts suggested that the nomenclature of NAFLD should be updated to metabolic-dysfunction-associated fatty liver disease (MAFLD). Hepatic fibrosis is the most significant determinant of all cause- and liver -related mortality in MAFLD. The non-invasive test (NIT) is urgently required to evaluate hepatic fibrosis in MAFLD. The fibrosis-4 (FIB-4) index is the first triaging tool for excluding advanced fibrosis because of its accuracy, simplicity, and cheapness, especially for general physicians or endocrinologists, although the FIB-4 index has several drawbacks. Accumulating evidence has suggested that vibration-controlled transient elastography (VCTE) and the enhanced liver fibrosis (ELF) test may become useful as the second step after triaging by the FIB-4 index. The leading cause of mortality in MAFLD is cardiovascular disease (CVD), extrahepatic malignancy, and liver-related diseases. MAFLD often complicates chronic kidney disease (CKD), resulting in increased simultaneous liver kidney transplantation. The FIB-4 index could be a predictor of not only liver-related mortality and incident hepatocellular carcinoma, but also prevalent and incident CKD, CVD, and extrahepatic malignancy. Although NITs as milestones for evaluating treatment efficacy have never been established, the FIB-4 index is expected to reflect histological hepatic fibrosis after treatment in several longitudinal studies. We here review the role of the FIB-4 index in the management of MAFLD.

Association between noninvasive assessment of liver fibrosis and coronary artery calcification progression in patients with nonalcoholic fatty liver disease

Advanced liver fibrosis and coronary artery calcification (CAC) progression has been reported to correlate with cardiovascular disease. This study investigated the association between noninvasive liver fibrosis score and CAC progression in patients with nonalcoholic fatty liver disease (NAFLD). We included 1173 asymptomatic adults with CAC scores from 2007–2013. CAC progression was defined as newly incident CAC or a ≥ 2.5-unit increase in the final CAC score square root. Liver fibrosis was assessed using fibrosis-4 index (FIB-4) score and NAFLD fibrosis score (NFS). A total of 293 (25.0%) subjects developed CAC. Mean baseline FIB-4 score was significantly higher in subjects with CAC. CAC progressed in 20.5% of subjects without NAFLD, 27.5% of those with NAFLD and low FIB-4 scores, and 35.9% of those with NAFLD and intermediate/high FIB-4 scores. On multivariate logistic regression analysis, the odds ratio for CAC progression was 1.70 (95% confidence interval, 1.12–2.58) for subjects with NAFLD plus intermediate/high FIB-4 scores versus those without NAFLD. In the sensitivity analysis, the odds ratio for CAC progression was 1.57 (95% confidence interval, 1.02–2.44) for subjects with NAFLD plus an intermediate/high NFS versus those without NAFLD. Advanced liver fibrosis stage assessed using noninvasive markers is associated with a higher risk of CAC progression in subjects with NAFLD.

Relationship between non-alcoholic fatty liver disease and coronary heart disease

Non-alcoholic fatty liver disease (NAFLD) is the leading cause of chronic liver disease and considered a liver manifestation of metabolic syndrome. It is in close relationship with insulin resistance, obesity, diabetes mellitus, all of which increase risk of cardiovascular disease (CVD). Besides, many studies point out that NAFLD independently contributes to the development of atherosclerosis and CHD. On the other hand, CVDs are the leading cause of death in NAFLD patients. Many pathophysiological changes and molecular mechanisms play an important role in NAFLD for CVD formation. Atherosclerosis is common in NAFLD, which also mainly contributes to the CVD formation and CHD. Many studies linking atherosclerotic CHD and NAFLD are present in the literature. Subclinical CHD, mainly detected by coronary computed tomography views, have been detected more common in NAFLD patients. Presence of NAFLD has been found to be more common in patients with severe CHD and in stable CHD, NAFLD has been found to be associated with more diffuse disease. In acute coronary syndromes, especially in acute myocardial infarction, patients with NAFLD have been found to have poor prognosis when compared with NAFLD free patients. In this review, our aim is to evaluate the relationship between NAFLD and CHD in detail and go over the pathophysiological mechanisms underlying this relationship.

Nonalcoholic fatty liver disease and cardiovascular disease phenotypes

Nonalcoholic fatty liver disease is increasingly recognized as a major global health problem. Intertwined with diabetes, metabolic syndrome, and obesity, nonalcoholic fatty liver disease embraces a spectrum of liver conditions spanning from steatosis to inflammation, fibrosis, and liver failure. Compared with the general population, the prevalence of cardiovascular disease is higher among nonalcoholic fatty liver disease patients, in whom comprehensive cardiovascular risk assessment is highly desirable. Preclinical effects of nonalcoholic fatty liver disease on the heart include both metabolic and structural changes eventually preceding overt myocardial dysfunction. Particularly, nonalcoholic fatty liver disease is associated with enhanced atherosclerosis, heart muscle disease, valvular heart disease, and arrhythmias, with endothelial dysfunction, inflammation, metabolic dysregulation, and oxidative stress playing in the background. In this topical review, we aimed to summarize current evidence on the epidemiology of nonalcoholic fatty liver disease, discuss the pathophysiological links between nonalcoholic fatty liver disease and cardiovascular disease, illustrate nonalcoholic fatty liver disease-related cardiovascular phenotypes, and finally provide a glimpse on the relationship between nonalcoholic fatty liver disease and cardiac steatosis, mitochondrial (dys)function, and cardiovascular autonomic dysfunction.

Nonalcoholic Fatty Liver Disease and the Heart: JACC State-of-the-Art Review

Nonalcoholic fatty liver disease (NAFLD) and cardiovascular disease (CVD) are both manifestations of end-organ damage of the metabolic syndrome. Through multiple pathophysiological mechanisms, CVD and NAFLD are associated with each other. Systemic inflammation, endothelial dysfunction, hepatic insulin resistance, oxidative stress, and altered lipid metabolism are some of the mechanisms by which NAFLD increases the risk of CVD. Patients with NAFLD develop increased atherosclerosis, cardiomyopathy, and arrhythmia, which clinically result in cardiovascular morbidity and mortality. Defining the mechanisms linking these 2 diseases offers the opportunity to further develop targeted therapies. The aim of this comprehensive review is to examine the association between CVD and NAFLD and discuss the overlapping management approaches.

Factors associated with advanced hepatic fibrosis in patients with various internal diseases: A multicenter community-based survey

BACKGROUND AND AIMS

Advanced hepatic fibrosis can occur in patients with various diseases, including diabetes mellitus and hypertension. We aimed to investigate the prevalence and risk factors of advanced hepatic fibrosis in patients with various internal diseases.

PATIENTS AND METHODS

We performed a community-based survey in which 1012 patients were enrolled (mean age, 63.1 ± 10.8 years; female/male, 505/507). Hepatic fibrosis was evaluated by Fib-4 index and patients were classified into high and low Fib-4 groups. Independent factors for the high Fib-4 group were analyzed using logistic regression and decision tree analysis.

RESULTS

A high prevalence of high Fib-4 index was observed in patients with cardiovascular diseases; 37.1% of patients with hypertension belonged to the high Fib-4 group. Independent factors associated with the high Fib-4 group were BMI (OR 0.95, 95%CI 0.918-0.989, P < 0.01), male sex (OR 1.35, 95%CI 1.03-1.78, P < 0.05), and hypertension (OR 1.41, 95%CI 1.03-1.92, P < 0.05). In patients with hypertension, a decision tree algorithm revealed three profiles for Fib-4 index: 1) creatinine level < 0.76 mg/dL (high Fib-4; 30.0%), 2) creatinine level ≥ 0.76 mg/dL without sodium-glucose cotransporter 2 inhibitor (SGLT2i) treatment (high Fib-4; 48.2%), and 3) creatinine level ≥ 0.76 mg/dL with SGLT2i treatment (high Fib-4; 23.5%).

CONCLUSIONS

A high prevalence of advanced hepatic fibrosis was observed in patients with hypertension. Hypertension was an independent risk factor, and creatinine level and SGLT2i were divergence variables for advanced hepatic fibrosis. Thus, hypertension with chronic kidney injury may exacerbate hepatic fibrosis, while SGLT2i treatment may ameliorate hepatic fibrosis.

The ABCC6 Transporter: A New Player in Biomineralization

Pseudoxanthoma elasticum (PXE) is an inherited metabolic disease with autosomal recessive inheritance caused by mutations in the ABCC6 gene. Since the first description of the disease in 1896, alleging a disease involving the elastic fibers, the concept evolved with the further discoveries of the pivotal role of ectopic mineralization that is preponderant in the elastin-rich tissues of the skin, eyes and blood vessel walls. After discovery of the causative gene of the disease in 2000, the function of the ABCC6 protein remains elusive. More than 300 mutations have been now reported and the concept of a dermal disease has progressively evolved toward a metabolic disorder resulting from the remote effects caused by lack of a circulating anti-mineralization factor. Very recently, evidence has accumulated that this anti-mineralizing factor is inorganic pyrophosphate (PPi). This leads to decreased PPi/Pi (inorganic phosphate) ratio that results from the lack of extracellular ATP release by hepatocytes and probably renal cells harboring the mutant ABCC6 protein. However, the mechanism by which ABCC6 dysfunction causes diminished ATP release remains an enigma. Studies of other ABC transporters, such as ABCC7 or ABCC1 could help our understanding of what ABCC6 exact function is. Data and a hypothesis on the possible roles of ABCC6 in acquired metabolic diseases are also discussed.

Clinical relevance of dual-energy X-ray absorptiometry (DXA) as a simultaneous evaluation of fatty liver disease and atherosclerosis in patients with type 2 diabetes

Background

Whole body dual-energy X-ray absorptiometry (DXA) can simultaneously measure both regional fat and non-fat mass. Android-to-gynoid (A/G) ratio measured by DXA has been reported to be associated with cardiovascular risks and visceral adiposity; however, little is known regarding its relationship with fatty liver disease and atherosclerosis among patients with diabetes. This study was designed to investigate the association of android and gynoid fat mass measured by DXA with fatty liver disease and atherosclerosis in patients with type 2 diabetes.

Methods

This is a cross-sectional study of 259 patients with type 2 diabetes (mean age 64 ± 13 years; 40.2 % female). Android and gynoid fat mass (kg) were measured by DXA. Skeletal muscle index (SMI) was calculated as appendicular non-fat mass (kg) divided by height (m²). Visceral fat area (VFA, cm²), subcutaneous fat area (SFA, cm²), and liver attenuation index (LAI) were assessed by abdominal computed tomography. Intima media thickness (IMT, mm) in common carotid arteries was determined by carotid ultrasonography.

Results

A/G ratio was significantly correlated with VFA (r = 0.72, p < 0.001), SFA (r = 0.32, p < 0.001) and LAI (r = −0.26, p < 0.001). A/G ratio (standardized β −0.223, p = 0.002) as well as VFA (standardized β −0.226, p = 0.001) were significantly associated with LAI in the univariate model. A/G ratio remained to be significantly associated with LAI (standardized β −0.224, p = 0.005) after adjusting for covariates including body mass index and transaminases. Among patients with low SMI (SMI < 7.0 in male and < 5.4 in female), A/G ratio was significantly associated with carotid IMT in the multivariate model (standardized β 0.408, p = 0.014).

Conclusions

DXA can be used to simultaneously estimate the risks for both fatty liver disease and atherosclerosis in patients with type 2 diabetes.