Therapeutic inhibition of apoC-III for the treatment of hypertriglyceridemia

Increased apolipoprotein C3 drives cardiovascular risk in type 1 diabetes

Type 1 diabetes mellitus (T1DM) increases the risk of atherosclerotic cardiovascular disease (CVD) in humans by poorly understood mechanisms. Using mouse models of T1DM-accelerated atherosclerosis, we found that relative insulin deficiency rather than hyperglycemia elevated levels of apolipoprotein C3 (APOC3), an apolipoprotein that prevents clearance of triglyceride-rich lipoproteins (TRLs) and their remnants. We then showed that serum APOC3 levels predict incident CVD events in subjects with T1DM in the Coronary Artery Calcification in Type 1 Diabetes (CACTI) study. To explore underlying mechanisms, we investigated the impact of Apoc3 antisense oligonucleotides (ASOs) on lipoprotein metabolism and atherosclerosis in a mouse model of T1DM. Apoc3 ASO treatment abolished the increased hepatic Apoc3 expression in diabetic mice - resulting in lower levels of TRLs - without improving glycemic control. APOC3 suppression also prevented arterial accumulation of APOC3-containing lipoprotein particles, macrophage foam cell formation, and the accelerated atherosclerosis in diabetic mice. Our observations demonstrate that relative insulin deficiency increases APOC3 and that this results in elevated levels of TRLs and accelerated atherosclerosis in a mouse model of T1DM. Because serum levels of APOC3 predicted incident CVD events in the CACTI study, inhibiting APOC3 might reduce CVD risk in T1DM patients.

Apolipoproteins C-II and C-III as nutritional markers unaffected by inflammation

BACKGROUND

Rapid turnover proteins (RTPs), such as transthyretin (TTR), retinol binding protein (RBP), and transferrin (Tf), provide an accurate assessment of nutritional status but are susceptible to inflammation. Lipid-related markers, which have short half-lives in serum, may be better suited for nutritional assessment. We sought to identify sensitive nutritional markers unaffected by inflammation.

METHODS

Fasting serum samples were collected from 30 malnourished inpatients and 25 healthy volunteers. Malnourished inpatients were divided into 2 groups: a low-C-reactive protein (CRP) group (CRP < 20 mg/l, n = 15) and a high-CRP group (CRP ≥ 20 mg/l, n = 15). Lipid-related markers, traditional nutritional markers, RTPs, micronutrients, and ketone bodies were measured and compared among the groups.

RESULTS

Apolipoprotein (Apo)C-II and ApoC-III concentrations were lower in malnourished inpatients than in the control group. There was no significant difference in ApoC-II and ApoC-III between the low- and high-CRP groups. Carnitine transporters and ketone bodies did not show a significant difference among the three groups. Albumin, TTR, RBP, and Tf concentrations were lowest in the high-CRP group, intermediate in the low-CRP group, and highest in the control group.

CONCLUSIONS

These results indicate that ApoC-II and ApoC-III are appropriate nutritional biomarkers unaffected by inflammation.

A convenient synthesis of 5'-triantennary N-acetyl-galactosamine clusters based on nitromethanetrispropionic acid

A convenient method for the synthesis of several triantennary GalNAc clusters based on a nitromethanetrispropionic acid core was developed. The synthetic approach involves pentafluorophenolic ester intermediates which can be used in a one-pot, seven reaction procedure to quickly prepare a variety of triantennary GalNAc conjugated ASOs. The GalNAc clusters were conjugated to the 5'-end of an antisense oligonucleotide and evaluated for activity in primary mouse hepatocytes where they showed ∼10-fold improvement in activity.