Measurement of apolipoprotein B levels helps in the identification of patients at risk for hypertriglyceridemic pancreatitis

Evaluation of apolipoprotein A5 variants: A cohort of patients with severe hypertriglyceridemia from Turkiye

BACKGROUND

This study aims to show the clinical and biochemical features in patients with severe hypertriglyceridemia (HTG) associated with rare variants in the apolipoprotein A-V (APOA5) gene.

MATERIALS AND METHODS

Demographics, blood lipid levels, body mass index (BMI) and APOA5 mutation subtypes were collected from the endocrinology clinic registry and analyzed for a retrospective cohort study of ten patients with severe HTG and APOA5 gene variants.

RESULTS

Of the 10 cases, four were female, and six were male. The median age was 45.0 years (min-max: 21-60 years), the median triglyceride was 2429.5 mg/dL (27.5 mmol/L) (min-max: 1351-4087 mg/dL, 15.3-46.2 mmol/L), and the mean BMI was calculated as 30.4 ± 4.4 kg/m2 (min-max: 24.9-41.0 kg/m2). Four cases had diabetes mellitus (DM); two were on intensive insulin therapy, and two were on basal insulin therapy. The mean hemoglobin A1c was 9.2 ± 1.2 % (min-max: 8.3-11.0 %). Among the study group, eight different APOA5 gene mutations were detected. These variants were heterozygous in 2 patients and homozygous (bi-allelic) in 8 patients. One patient was homozygous for APOA5 p.Ser19Trp, a relatively common polymorphism that is a risk variant for HTG.

CONCLUSION

We report a cohort of patients with biallelic and single copy APOA5 variants, who were diagnosed later in life. Most had secondary factors, such as DM or obesity with increased BMI. Most rare APOA5 variants found in our patients were of uncertain significance. Our results add to the growing evidence that rare variants in certain candidate genes may predispose to developing HTG, together with secondary factors such as obesity. The genetic basis of HTG in many other patients is still unknown and remains the subject of further investigation.

Association of Apolipoprotein A5 Gene Variants with Hyperlipidemic Acute Pancreatitis in Southeastern China

Background: Apolipoprotein A5 (APOA5) is involved in serum triglyceride (TG) regulation. Several studies have reported that the rs651821 locus in the APOA5 gene is associated with serum TG levels in the Chinese population. However, no research has been performed regarding the association between the variants of rs651821 and the risk of hyperlipidemic acute pancreatitis (HLAP). Methods: A case-control study was conducted and is reported following the STROBE guidelines. We enrolled a total of 88 participants in this study (60 HLAP patients and 28 controls). APOA5 was genotyped using PCR and Sanger sequencing. Logistic regression models were conducted to calculate odds ratios and a 95% confidence interval. Results: The genotype distribution of the rs651821 alleles in both groups follow the Hardy-Weinberg distribution. The frequency of the "C" allele in rs651821 was increased in HLAP patients compared to controls. In the recessive model, subjects with the "CC" genotype had an 8.217-fold higher risk for HLAP (OR = 8.217, 95% CI: 1.023-66.01, p = 0.046) than subjects with the "TC+TT" genotypes. After adjusting for sex, the association remained significant (OR = 9.898, 95% CI: 1.176-83.344, p = 0.035). Additionally, the "CC" genotype was related to an increased TG/apolipoprotein B (APOB) ratio and fasting plasma glucose (FPG) levels. Conclusions: Our findings suggest that the C allele of rs651821 in APOA5 increases the risk of HLAP in persons from Southeastern China.

A novel regulatory facet for hypertriglyceridemia: The role of microRNAs in the regulation of triglyceride-rich lipoprotein biosynthesis

Atherosclerotic cardiovascular disease (ASCVD) is one of the major leading global causes of death. Genetic and epidemiological studies strongly support the causal association between triacylglycerol-rich lipoproteins (TAGRL) and atherogenesis, even in statin-treated patients. Recent genetic evidence has clarified that variants in several key genes implicated in TAGRL metabolism are strongly linked to the increased ASCVD risk. There are several triacylglycerol-lowering agents; however, new therapeutic options are in development, among which are miRNA-based therapeutic approaches. MicroRNAs (miRNAs) are small non-coding RNAs (18-25 nucleotides) that negatively modulate gene expression through translational repression or degradation of target mRNAs, thereby reducing the levels of functional genes. MiRNAs play a crucial role in the development of hypertriglyceridemia as several miRNAs are dysregulated in both synthesis and clearance of TAGRL particles. MiRNA-based therapies in ASCVD have not yet been applied in human trials but are attractive. This review provides a concise overview of current interventions for hypertriglyceridemia and the development of novel miRNA and siRNA-based drugs. We summarize the miRNAs involved in the regulation of key genes in the TAGRLs synthesis pathway, which has gained attention as a novel target for therapeutic applications in CVD.

Clinical Management of Hypertriglyceridemia in the Prevention of Cardiovascular Disease and Pancreatitis

Purpose of Review

Hypertriglyceridemia (HTG) is common and is a significant contributor to atherosclerosis and pancreatitis risk. Specific HTG treatments have had variable success in reducing atherosclerosis risk. Novel therapies for severe HTG treatment and pancreatitis risk reduction are likely to be available soon. These novel therapies are expected to have broader applications for more moderate HTG and atherosclerosis risk reduction as well.

Recent Findings

NHANES 2012 data has confirmed a reduction in average triglyceride (TG) levels in the US population. Dietary modification and weight reduction when needed remain the core treatment elements for all individuals with HTG, while statin therapy is a foundational pharmacologic care for atherosclerotic cardiovascular disease (ASCVD) event risk reduction. In addition, the REDUCE-IT study provides evidence for additional benefit from the use of high-dose icosapent ethyl (IPE) on top of background medical therapy in adults with moderate HTG and ASCVD or type 2 diabetes mellitus (T2D) and additional ASCVD risk factors. However, treatment with eicosapentaenoic acid (EPA) combined with docosahexanoic acid (DHA) did not reduce ASCVD in a similar population studied in the STRENGTH trial. Furthermore, novel therapeutics targeting PPAR-ɑ, as well as ApoC-III and AngPTL3, effectively lower TG levels in individuals with moderate and severe HTG, respectively. These treatments may have applicability for reducing risk from ASCVD among individuals with chylomicronemia; in addition, ApoC-III and AngPTL3 treatments may have a role in treating individuals with the rare monogenic familial chylomicronemia syndrome (FCS) at risk for acute pancreatitis (AP).

Summary

Residual ASCVD risk in individuals treated with contemporary care may be due in part to non-LDL lipid abnormalities including HTG. The findings from REDUCE-IT, but not STRENGTH, confirm that consumption of high-dose EPA may reduce ASCVD risk, while combination therapy of EPA plus DHA does not reduce ASCVD in a similar population. TG lowering likely reduces ASCVD risk in individuals with HTG, but ASCVD risk is multifactorial; the added benefit of IPE to contemporary preventive therapy is the consequence of differential non-TG biologic properties between the two fatty acids. Acute pancreatitis is more difficult to study prospectively since it is less common; however, TG lowering is likely critical for the care of at-risk individuals. Additional benefit from novel therapy that has an impact on this otherwise refractory condition is anticipated.

The association of parameters of body composition and laboratory markers with the severity of hypertriglyceridemia-induced pancreatitis

BACKGROUND

Hypertriglyceridemia has arisen as the third leading cause of acute pancreatitis. This study aimed at exploring the association between the severity of hypertriglyceridemia-induced pancreatitis (HTGP) and computed tomography (CT)-based body composition parameters and laboratory markers.

METHODS

Laboratory and clinical parameters were collected from 242 patients with HTGP between 2017 and 2020. Severity of HTGP was evaluated by original or modified CT severity index. Body composition parameters such as area and radiodensity of muscle, subcutaneous adipose tissue and visceral adipose tissue were calculated by CT at the level of third lumbar vertebra. Parameters were compared between mild and moderately severe to severe HTGP. Uni-variate and multi-variate Logistic regression analyses were employed to assess the risk factors of the severity of HTGP.

RESULTS

Seventy patients (28.9%) presented with mild HTGP. Body mass index, waist circumference and all CT-based body composition parameters differed between male and female patients. None was associated with the severity of HTGP, neither in males nor in females. Receiver operating characteristic curves showed that areas under the curves of apolipoprotein A-I and albumin to predict the severity of HTGP were 0.786 and 0.759, respectively (all P < 0.001). Uni-variate and further multi-variate Logistic regression analysis confirmed that low serum albumin (< 35 g/L, P = 0.004, OR = 3.362, 95%CI = 1.492-8.823) and apolipoprotein A-I (< 1.1 g/L, P < 0.001, OR = 5.126, 95%CI = 2.348-11.195), as well as high C-reactive protein (> 90 mg/L, P = 0.005, OR = 3.061, 95%CI = 1.407-6.659) and lipase (P = 0.033, OR = 2.283, 95%CI = 1.070-4.873) were risk factors of moderately severe to severe HTGP. Levels of albumin, apolipoprotein A-I, C-reactive protein and lipase were also associated with the length of hospital stay (all P < 0.05). Besides, low serum albumin, low-density lipoprotein cholesterol and high radiodensity of subcutaneous adipose tissue were significant risk factors of pancreatic necrosis in patients with HTGP (all P < 0.05).

CONCLUSIONS

Low serum albumin and apolipoprotein A-I, and high C-reactive protein and lipase upon admission were associated with a more severe type of HTGP and longer hospital stay for these patients. Albumin and apolipoprotein A-I may serve as novel biomarkers for the severity of HTGP. However, none of the body composition parameters was associated with the severity of HTGP.