Effects of antiretroviral therapy on proprotein convertase subtilisin/kexin 9: focus on lipids, inflammation and immunovirological parameters

OBJECTIVES

Plasma levels of proprotein convertase subtilisin/kexin type 9 (PCSK9), a major regulator of cholesterol metabolism, have been reported to have an increasing trend in people living with HIV (PLWH) compared with controls. We assessed the impact of different antiretroviral (ARV) regimens on plasma PCSK9 levels as well as plasma lipids, systemic inflammation and immunovirological parameters.

METHODS

Eighty HIV-positive ARV therapy (ART)-naïve PLWH and 40 uninfected controls were retrospectively enrolled. At baseline and 3, 6 and 12 months after ART initiation, plasma PCSK9 levels, lipids, high-sensitivity C-reactive protein (hs-CRP), HIV-1 RNA levels and CD4 T-cell count were measured.

RESULTS

Baseline PCSK9 levels were significantly more elevated in PLWH and were associated with HIV-1 RNA levels (P < 0.001), CD4 T-cell counts (P < 0.001), triglycerides (P < 0.001) and high-density lipoprotein (HDL) cholesterol (P < 0.001), but not with total cholesterol, low-density lipoprotein (LDL) cholesterol and lipoprotein(a) levels. The prescription of ART was paralleled by significant decreases in plasma PCSK9 and hs-CRP levels, and increases in total cholesterol, LDL cholesterol, HDL cholesterol, triglycerides and lipoprotein(a), independent of regimen.

CONCLUSIONS

PCSK9 levels, along with systemic inflammation, were progressively reduced following the initiation of an effective ART. However, at the end of the study PCSK9 levels remained higher than in controls and did not correlate with any of the lipid variables.

P873Plasma PCSK9 levels and atherosclerosis burden in the coronary arteries of patients undergoing coronary angiography

Background

Plasma PCSK9 levels, a novel and effective therapeutic target for CVD prevention, have been associated with CVD events irrespective of traditional risk factors. Whether PCSK9 levels predict coronary artery disease (CAD) burden and severity is a matter of dispute.

Purpose

To investigate the association between plasma PCSK9 levels and CAD characteristics, including number of major diseased vessels, severity of coronary stenosis, and the burden of coronary calcifications.

Methods

One hundred and one patients undergoing coronary angiography were recruited for this cross-sectional study. The number of major coronary diseased vessels was defined as the presence of ≥1 stenoses ≥50% in diameter of at least one major coronary artery. CAD severity was defined as either the absence of coronary stenosis (no-CAD), CAD<50% or CAD≥50% in one or more coronary arteries. The burden of coronary calcifications was estimated by angiography visual inspection and classified as absent, mild, moderate or severe.

Results

Coronary angiography showed single, double and triple vessel disease in 26 (25.7%), 23 (22.8%) and 21 (20.8%) patients, respectively; 20 (19.8%) and 11 (10.9%) pts had either minimal CAD (<50%) or normal angiographic findings. Also, calcifications were absent in 65 patients (64.4%), and mild, moderate and severe in 23 (22.8%), 11 (10.9%) and 2 (2%) patients, respectively. Plasma PCSK9 levels were significantly associated with age (rho=0.22, p=0.025) and SBP (rho=0.21, p=0.034), and were almost doubled in patients with chronic kidney disease (CKD) as compared to those without CKD [164.6 ng/mL (104.6–187.0) vs 94.8 ng/mL (86.8–114.9), p=0.006]. Among patients without CKD, those with CAD≥50% had higher plasma PCSK9 levels than those without [97.1 ng/mL (87.8–143.0) vs 83.2 ng/mL (73.4–102.6), p=0.04]. In the overall population, higher plasma PCSK9 levels were found in pts with triple vessel disease [165.7 ng/mL (121.3–180.5)] than in those with double/single vessel involvement [97.9 ng/mL (87.6–99.8) and 88.4 ng/mL (87.3–97.4), p<0.001 for both comparisons] or without CAD [87.5 ng/mL (74.3–114.9), p<0.001]. Also, a trend toward an increase of plasma PCSK9 levels was found with higher CAD severity [no-CAD: 87.5 ng/mL (74.3–114.9), CAD<50%: 89.1 ng/mL (78.9–105.3), CAD≥50%: 97.6 ng/mL (87.9–155.3), p=0.051], which turned significant after exclusion of CKD patients (p=0.042). Adjustment for age, sex, plasma LDL-cholesterol levels, statin use and CKD abolished the association between PCSK9 and CAD severity but not with the number of significantly diseased vessels and the burden of coronary calcifications.

Conclusions

Circulating PCSK9, whose plasma levels are significantly influenced by the presence of CKD, discriminates patients with significant coronary artery stenosis from those without CAD. In addition, both the number of diseased coronary vessels and total coronary calcifications are independently predicted by an elevated plasma PCSK9 level.

Acknowledgement/Funding

None

Uric acid and bone mineral density in postmenopausal osteoporotic women: the link lies within the fat

The association between serum uric acid (SUA) levels and bone mineral density (BMD) is controversial. Fat accumulation is linked to SUA and BMD, thus possibly explaining the mixed results. We found that adiposity drives part of the association between SUA and BMD in women with postmenopausal osteoporosis.

INTRODUCTION

Both positive and negative associations between SUA and BMD have been reported. SUA levels and BMD increase with higher body weight and other indices of adiposity; hence, the association between SUA and BMD might be a consequence of the confounding effect of adiposity. We investigated in this cross-sectional study whether the association between SUA and BMD is independent of measures of fat accumulation and other potential confounders.

METHODS

SUA levels, femur BMD, markers of bone metabolism, body mass index (BMI), fat mass (FM), waist circumference (WC), and abdominal visceral fat area were measured in 180 treatment-naive postmenopausal osteoporotic women (mean age 66.3 ± 8.5 years, age range 48-81 years).

RESULTS

Women with higher SUA levels (third tertile) had significantly higher femur BMD and lower cross-linked C-terminal telopeptide of type I collagen (CTX) and bone alkaline phosphatase (bALP) levels. SUA levels were positively associated with all indices of adiposity. In multivariable analysis with femur BMD as dependent variable, the association between logarithmic (LG)-transformed SUA levels and BMD (beta = 0.42, p < 0.001) was lessened progressively by the different indices of adiposity, like LG-BMI (beta = 0.22, p = 0.007), LG-WC (beta = 0.21, p = 0.01), LG-FM (beta = 0.18, p = 0.01), and LG-abdominal visceral fat area (beta = 0.12, p = 0.05). The association between SUA levels and markers of bone metabolism was dependent on the effect of confounders.

CONCLUSION

In postmenopausal osteoporotic women, the strong univariable association between SUA levels and femur BMD is partly explained by the confounding effect of indices of adiposity.

Autophagy regulates satellite cell ability to regenerate normal and dystrophic muscles

Autophagy is emerging as a key regulatory process during skeletal muscle development, regeneration and homeostasis, and deregulated autophagy has been implicated in muscular disorders and age-related muscle decline. We have monitored autophagy in muscles of mdx mice and human Duchenne muscular dystrophy (DMD) patients at different stages of disease. Our data show that autophagy is activated during the early, compensatory regenerative stages of DMD. A progressive reduction was observed during mdx disease progression, in coincidence with the functional exhaustion of satellite cell-mediated regeneration and accumulation of fibrosis. Moreover, pharmacological manipulation of autophagy can influence disease progression in mdx mice. Of note, studies performed in regenerating muscles of wild-type mice revealed an essential role of autophagy in the activation of satellite cells upon muscle injury. These results support the notion that regeneration-associated autophagy contributes to the early compensatory stage of DMD progression, and interventions that extend activation of autophagy might be beneficial in the treatment of DMD. Thus, autophagy could be a 'disease modifier' targeted by interventions aimed to promote regeneration and delay disease progression in DMD.