Lipoprotein(a) in cirrhosis. A new index of liver functions?

Role of Cardiac Biomarkers in Hepatic Disorders: A Literature Review

Various studies have reported the association between cardiac markers and hepatic disorders. The main objective of this review article was to elucidate the significance of important cardiac indicators such as ischemia-modified albumin, cardiac troponin, cardiac natriuretic peptides, creatine kinase, creatine kinase-MB, lactate dehydrogenase, heart-type fatty acid-binding protein, osteopontin, soluble suppression of tumorigenicity 2, C-reactive protein, and lipoprotein(a) in the development of hepatic disorders. In addition, it highlighted recent notable discoveries and accomplishments in this field and identified areas requiring further investigation, ongoing discussions, and potential avenues for future research. Early identification and control of these cardiac markers might be helpful to control the prevalence of hepatic disorders associated with cardiovascular diseases.

Lipoprotein(a) and residual vascular risk in statin-treated patients with first acute ischemic stroke: A prospective cohort study

OBJECTIVES

Statins either barely affect or increase lipoprotein(a) [Lp(a)] levels. This study aimed to explore the factors correlated to the change of Lp(a) levels as well as the relationship between Lp(a) and the recurrent vascular events in statin-treated patients with first acute ischemic stroke (AIS).

METHODS

Patients who were admitted to the hospital with first AIS from October 2018 to September 2020 were eligible for inclusion. Correlation between the change of Lp(a) levels and potential influencing factors was assessed by linear regression analysis. Cox proportional regression models were used to estimate the association between Lp(a) and recurrent vascular events including AIS, transient ischemic attack, myocardial infarction and coronary revascularization.

RESULTS

In total, 303 patients, 69.6% males with mean age 64.26 ± 11.38 years, completed the follow-up. During the follow-up period, Lp(a) levels increased in 50.5% of statin-treated patients and the mean percent change of Lp(a) levels were 14.48% (95% CI 6.35-22.61%). Creatinine (β = 0.152, 95% CI 0.125-0.791, P = 0.007) and aspartate aminotransferase (AST) (β = 0.160, 95% CI 0.175-0.949, P = 0.005) were positively associated with the percent change of Lp(a) levels. During a median follow-up of 26 months, 66 (21.8%) patients had a recurrent vascular event. The median time period between AIS onset and vascular events recurrence was 9.5 months (IQR 2.0-16.3 months). The on-statin Lp(a) level ≥70 mg/dL (HR 2.539, 95% CI 1.076-5.990, P = 0.033) and the change of Lp(a) levels (HR 1.003, 95% CI 1.000-1.005, P = 0.033) were associated with the recurrent vascular events in statin-treated patients with first AIS. Furthermore, the on-statin Lp(a) levels ≥70 mg/dL (HR 3.612, 95% CI 1.018-12.815, P = 0.047) increased the risk of recurrent vascular events in patients with low-density lipoprotein cholesterol (LDL-C) levels < 1.8 mmol/L.

CONCLUSIONS

Lp(a) levels increased in half of statin-treated patients with first AIS. Creatinine and AST were positively associated with the percent change of Lp(a) levels. Lp(a) is a determinant of residual vascular risk and the change of Lp(a) is positively associated with the risk of recurrent vascular events in these patients.

The Ability of Lipoprotein (a) Level to Predict Early Carotid Atherosclerosis Is Impaired in Patients With Advanced Liver Fibrosis Related to Metabolic-Associated Fatty Liver Disease

INTRODUCTION

Hepatic fibrosis reduces the serum level of lipoprotein (a) (Lp(a)) and may affect its accuracy in cardiovascular disease prediction of metabolic-associated fatty liver disease (MAFLD). We aimed to estimate the association between Lp(a) levels and the risk of carotid atherosclerosis in MAFLD patients with advanced fibrosis.

METHODS

This was a cross-sectional study enrolling 4,348 consecutive individuals (1,346 patients with MAFLD and 3,002 non-MAFLD patients) who were admitted to the First Affiliated Hospital, Sun Yat-sen University, and underwent abdominal and carotid ultrasonography from 2015 to 2021. Lp(a) levels, liver biochemical markers, metabolic indices, and anthropometric parameters were measured. Liver fat content and fibrosis severity were assessed by MRI-PDFF, using the NAFLD fibrosis score (NFS) and liver stiffness measurement (LSM) of two-dimensional shear wave elastography, respectively.

RESULTS

There was an L-shaped relationship between Lp(a) levels and LSMs in patients with MAFLD, and Lp(a) levels had a different relationship with liver fat content in MAFLD patients with F1-2 versus those with F3-4. Non-MAFLD patients had higher levels of Lp(a) than MAFLD patients with or without advanced fibrosis (both P < 0.05). Lp(a) levels and degree of liver fibrosis were both positively correlated with carotid atherosclerosis in patients with MAFLD. Lp(a) levels performed well on carotid atherosclerosis risk prediction for non-MAFLD patients with an area under the curve (AUC) of 0.819, which was significantly better than the carotid atherosclerosis risk prediction for MAFLD patients with NFS ≤ -1.836 (AUC: 0.781), NFS > -1.836 (AUC: 0.692), and LSM ≥ 9.0 kPa (AUC: 0.635) (all P < 0.05).

DISCUSSION

Advanced liver fibrosis significantly reduces the predictive value of Lp(a) levels for the risk of carotid atherosclerosis in patients with MAFLD.

Lipoprotein(a) as a potential marker of residual liver function in hepatocellular carcinoma

The residual liver function is a major clinical index in hepatocellular carcinoma (HCC) patients. As the liver plays a crucial role in lipid and lipoprotein metabolism, the significant impairment of the hepatic function occurring during chronic liver diseases, such as HCC, can influence plasma lipoprotein profiles. Although, lipoprotein(a) (Lp(a)) circulating concentrations are mostly determined by genetic factors, in the majority of reports they have shown a correlation with the hepatic status and a significant decrease in HCC and liver cirrhosis patients than among the controls. In such a way, Lp(a) may represent a new additional and useful marker for a more complete assessment and monitoring of the liver function in patients with HCC and liver cirrhosis. Further studies are needed in order to evaluate the clinical significance of Lp(a) in HCC.

Increased plasma apoM levels in the patients suffered from hepatocellular carcinoma and other chronic liver diseases

OBJECTIVE

To determine plasma apolipoprotein M (apoM) levels and other lipid profiles in hepatocellular carcinoma (HCC) patients compared to other chronic liver diseases and normal subjects.

MATERIALS AND METHODS

36 HCC, 68 chronic hepatitis, 29 liver cirrhosis patients and 64 normal controls were subjected in the present study. Serum lipids, lipoproteins, apolipoprotein AI (apoAI) and apoB were determined by the conventional methods. Plasma apoM levels were semi-quantitatively determined by both dot-blotting and western blotting analysis.

RESULTS

Serum levels of triglycerides (TG), HDL-cholesterol, apoAI and lipoprotein (a) (Lp(a)) were significantly lower in the HCC patients than in the normal subjects, whereas there were no obvious differences on serum total cholesterol, LDL-cholesterol and apoB between HCC patients and normal subjects. However, plasma apoM levels in HCC patients were significantly increased than those in the normal subjects, but lower than those in the chronic hepatitis and cirrhosis patients.

CONCLUSION

It is concluded that serum TG, apoAI, HDL-C and Lp(a) were significantly decreased in HCC patients than in controls, whereas plasma apoM levels were significantly increased in the HCC patients. Decreased serum TG, apoAI, HDL-C and Lp(a) may reflect the liver damage in HCC patients, whereas the clinical significance of increased plasma apoM levels in relation to HCC is not clear.

Lipids changes in liver cancer

Liver is one of the most important organs in energy metabolism. Most plasma apolipoproteins and endogenous lipids and lipoproteins are synthesized in the liver. It depends on the integrity of liver cellular function, which ensures homeostasis of lipid and lipoprotein metabolism. When liver cancer occurs, these processes are impaired and the plasma lipid and lipoprotein patterns may be changed. Liver cancer is the fifth common malignant tumor worldwide, and is closely related to the infections of hepatitis B virus (HBV) and hepatitis C virus (HCV). HBV and HCV infections are quite common in China and other Southeast Asian countries. In addition, liver cancer is often followed by a procession of chronic hepatitis or cirrhosis, so that hepatic function is damaged obviously on these bases, which may significantly influence lipid and lipoprotein metabolism in vivo. In this review we summarize the clinical significance of lipid and lipoprotein metabolism under liver cancer.

Influence of liver cancer on lipid and lipoprotein metabolism

Liver plays a key role in the metabolism of plasma apolipoproteins, endogenous lipids and lipoproteins. Hepatocellular carcinoma (HCC) is one of the most common fatal malignant tumors in China and in other Southeast Asian countries. This has been attributed to the high incidence of hepatitis B infection. Hepatitis B proteins, such as the hepatitis B X protein (HBx) that is large hepatitis B surface protein could regulate transcription of many candidate genes for liver carcinogenesis. It has known that patients who suffered from acute hepatitis B could have lipid disorders such as decreased plasma level of high-density lipoproteins (HDL). Furthermore, aberrations of lipid metabolism are often seen in the chronic hepatitis B infection. Plasma lipid profiles could be changed under HCC. In majority of the reports in HCC, plasma levels of triglycerides (TG), cholesterol, free fatty acids (FFA), HDL, low-density lipoproteins (LDL), lipoprotein (a) (Lp(a)), apolipoprotein AI (apoAI) and apoB were slight to significantly decreased, however, in some cases plasma levels of TG and Lp(a) might be increased. It has been suggested that analysis of plasma levels of lipids, lipoproteins and apolipoproteins in the patients suffered from HCC reflects on the hepatic cellular impairment status. Studies revealed that alterations seen in the plasma levels of lipids, lipoproteins and apolipoproteins reflecting patients' pathologic conditions. Decreased serum levels of cholesterol and apoAI may indicate a poor prognosis. Human leukaemic cells and certain tumor tissues have a higher receptor-mediated uptake of HDL and LDL than the corresponding normal cells or tissues. LDL and HDL have therefore been proposed as a carrier for the water-insoluble anti-cancer agents.

Low incidence of vascular complications in patients with diabetes mellitus associated with liver cirrhosis as compared with type 2 diabetes mellitus

We compared clinical features and vascular complications of patients with diabetes mellitus associated with liver cirrhosis versus patients with type 2 diabetes mellitus. Subjects were 19 patients (LC-DM group) in whom diabetes was diagnosed after development of liver cirrhosis. Control consisted of 38 patients with type 2 diabetes (T2DM group) matched for sex, age, duration of diabetes, body mass index, treatment, and degree of glycemic control, which was determined by glycoalbumin. The LC-DM group had significantly more smokers, higher serum insulin levels, more insulin resistance calculated by homeostasis model assessment, lower blood counts (white and red blood cells, hemoglobin, and platelets), and lower serum levels of total cholesterol, triglyceride, low density lipoprotein cholesterol and lipoprotein (Lp)(a) than the T2DM group. The incidence of diabetic retinopathy and cerebrovascular disease was significantly lower in the LC-DM group compared to the T2DM group. Logistic regression analysis indicated that Lp(a) and the diabetes duration were significant predictors for the retinopathy, while Lp(a) was a significant predictor for the cerebrovascular complication. In diabetes associated with liver cirrhosis, the incidence of diabetic retinopathy and cerebrovascular disease is lower than in type 2 diabetes mellitus in this study, probably because of lower levels of serum Lp(a).

Candidate-based proteomics in the search for biomarkers of cardiovascular disease

The key concept of proteomics (looking at many proteins at once) opens new avenues in the search for clinically useful biomarkers of disease, treatment response and ageing. As the number of proteins that can be detected in plasma or serum (the primary clinical diagnostic samples) increases towards 1000, a paradoxical decline has occurred in the number of new protein markers approved for diagnostic use in clinical laboratories. This review explores the limitations of current proteomics protein discovery platforms, and proposes an alternative approach, applicable to a range of biological/physiological problems, in which quantitative mass spectrometric methods developed for analytical chemistry are employed to measure limited sets of candidate markers in large sets of clinical samples. A set of 177 candidate biomarker proteins with reported associations to cardiovascular disease and stroke are presented as a starting point for such a 'directed proteomics' approach.

alpha-Tocopherol modulates liver toxicity of the pyrethroid cypermethrin

The objective of the current study was to analyze the hepatotoxic effect caused by cypermethrin (CYP) in rats, and to evaluate the possible protective effect of the antioxidant alpha-tocopherol (alpha-T). Fifty male Wistar rats were given daily i.p. doses of 300 mg/kg per day of CYP during 7 days. Half of them were administered three previous doses of 100 mg/kg per day of alpha-T, followed by seven subsequent oral doses of 40 mg/kg per day of alpha-T. The levels of biochemical indicators and histological liver damage were determined, as well as DCVA in urine. CYP altered the lipid metabolism. Such alterations were inhibited 32% by alpha-T, except for LDL. Alterations in AST were modulated in 29%. In the histology, alpha-T reduced mitochondria damage, and swelling of the endoplasmic reticulum of the liver cells. The results suggest that alpha-T can modify CYP metabolism, changing the lipidic profile and the histological analysis.

Changes in lipoprotein(a) concentration after orthotopic heart transplantation

BACKGROUND

Elevated concentrations of lipoprotein(a) have been considered an important risk factor in the development of premature cardiovascular disease and have been proposed as a risk factor in the development of accelerated cardiac allograft vasculopathy after orthotopic heart transplantation.

METHODS

We prospectively measured lipoprotein(a), fasting cholesterol, and triglyceride concentrations before (n = 38), 6 months (n = 38), and 1 year (n = 21) after orthotopic heart transplantation. The mean age of the patients was 52 +/- 2 years. Eighty-seven percent of the patients were men, 82% were white, and 61% had ischemic cardiomyopathy.

RESULTS

Mean lipoprotein(a) concentration was lower 6 months after transplantation than it was before the operation (23 +/- 3 mg/dL vs 17 +/- 3 mg/dL; P =.014) and remained low 1 year after transplantation (23 +/- 3 mg/dL vs 18 +/- 4 mg/dL; P = not significant). In contrast, mean cholesterol concentration was higher 6 months after transplantation (171 +/- 8 mg/dL vs 221 +/- 8 mg/dL; P <.001) and 1 year (171 +/- 8 mg/dL vs 205 +/- 10 mg/dL; P <.01) than it was before transplantation. Triglyceride concentration was higher 1 year after transplantation than it was before the operation (146 +/- 13 mg/dL vs 184 +/- 20 mg/dL; P =.017).

CONCLUSIONS

Lipoprotein(a) concentrations decrease during the 6 months after transplantation and stay low for at least 1 year after the operation. Additional studies are needed to ascertain the effect these changes in lipoprotein(a) concentration on the development of cardiac allograft vasculopathy.