Decreased serum PCSK9 levels after ischaemic stroke predict worse outcomes

PCSK9 in Vascular Aging and Age-Related Diseases

The aging process significantly contributes to human disease, and as worldwide life expectancy increases, addressing the challenges of aging and age-related cardiovascular diseases is becoming increasingly urgent. Vascular aging is a key link between aging and the development of age-related diseases. Recent studies indicate that proprotein convertase subtilisin/kexin type 9 (PCSK9), a type of protein involved in the metabolism of lipids, is crucial in modulating vascular aging by affecting the physiological functioning of vascular cells. PCSK9 is linked to lipid metabolism and chronic inflammation and is involved in regulating senescence-related activities, including migration, proliferation, apoptosis, and differentiation. These factors contribute to the aging of vascular cells and age-related vascular diseases, including atherosclerosis, hypertension, coronary artery disease, and cerebrovascular diseases. Given its involvement in these processes, this article provides a comprehensive summary of PCSK9's regulatory functions in vascular aging, highlighting potential therapeutic targets for combating age-related cardiovascular diseases.

Function of proprotein convertase subtilisin/kexin type 9 and its role in central nervous system diseases: An update on clinical evidence

Proprotein convertase subtilisin/kexin type 9 (PCSK9) has attracted lots of attention in preventing the clearance of plasma low-density lipoprotein cholesterol (LDL-C). PCSK9 inhibitors are developed to primarily reduce the cardiovascular risk by lowering LDL-C level. Recently, a number of pleiotropic extrahepatic functions of PCSK9 beyond the regulation of cholesterol metabolism, particularly its effects on central nervous system (CNS) diseases have been increasingly identified. Emerging clinical evidence have revealed that PCSK9 may play a significant role in neurocognition, depression, Alzheimer's disease, and stroke. The focus of this review is to elucidate the functions of PCSK9 and highlight the effects of PCSK9 in CNS diseases, with the aim of identifying the potential risks that may arise from low PCSK9 level (variant or inhibitor) in the clinical practice.

The Role of Vascular Aging in Atherosclerotic Plaque Development and Vulnerability

BACKGROUND

The ongoing demographical shift is leading to an unprecedented aging of the population. As a consequence, the prevalence of age-related diseases, such as atherosclerosis and its thrombotic complications is set to increase in the near future. Endothelial dysfunction and vascular stiffening characterize arterial aging and set the stage for the development of cardiovascular diseases. Atherosclerotic plaques evolve over time, the extent to which these changes might affect their stability and predispose to sudden complications remains to be determined. Recent advances in imaging technology will allow for longitudinal prospective studies following the progression of plaque burden aimed at better characterizing changes over time associated with plaque stability or rupture. Oxidative stress and inflammation, firmly established driving forces of age-related CV dysfunction, also play an important role in atherosclerotic plaque destabilization and rupture. Several genes involved in lifespan determination are known regulator of redox cellular balance and pre-clinical evidence underlines their pathophysiological roles in age-related cardiovascular dysfunction and atherosclerosis.

OBJECTIVE

The aim of this narrative review is to examine the impact of aging on arterial function and atherosclerotic plaque development. Furthermore, we report how molecular mechanisms of vascular aging might regulate age-related plaque modifications and how this may help to identify novel therapeutic targets to attenuate the increased risk of CV disease in elderly people.

PCSK9 loss-of-function variants and risk of infection and sepsis in the Reasons for Geographic and Racial Differences in Stroke (REGARDS) cohort

BACKGROUND

Elevated proprotein convertase subtilisin/kexin type 9 (PCSK9) levels have been associated with adverse outcomes in patients hospitalized for sepsis. PCSK9 loss-of-function (LOF) variants area associated with lower low-density lipoprotein cholesterol (LDL-C) levels. Decreased LDL-C is a biomarker of acute and chronic infection and sepsis risk. We examined the association between presence of two genetic PCSK9 LOF variants and risk of infection and sepsis in community-dwelling adults.

METHODS

We analyzed data from 10,924 Black participants tested for PCSK9 LOF variants in the REasons for Geographic and Racial Differences in Stroke (REGARDS) cohort. The primary endpoint was hospitalization for a serious infection. Within serious infection hospitalizations, we defined sepsis as ≥2 system inflammatory response syndrome criteria. Using multivariable Cox and logistic regression, we investigated the association between LOF variants and hospitalization for infection and sepsis events, adjusting for sociodemographics, health behaviors, chronic medical conditions and select biomarkers.

RESULTS

Among 10,924 Black participants, PCSK9 LOF variants were present in 244 (2.2%). Serious infection hospitalizations occurred in 779 participants (14 with PCSK9 variants and 765 without). The presence of PCSK9 variants was not associated with infection risk (adjusted HR 0.68; 95% CI: 0.38-1.25). Among participants hospitalized for a serious infection, the presence of PCSK9 variants was not associated with sepsis (adjusted OR 7.31; 95% CI = 0.91-58.7).

CONCLUSIONS

PCSK9 LOF variants are not associated with increased risk of hospitalization for a serious infection. Among those hospitalized for a serious infection, PCSK9 LOF variants was not associated with odds of sepsis.

Serum PCSK9 levels predict the occurrence of acute coronary syndromes in patients with severe carotid artery stenosis

BACKGROUND

The pharmacological inhibition of Proprotein Convertase Subtilisin/Kexin type 9 (PCSK9) has shown to dramatically impact on low-density lipoprotein-cholesterol (LDL-C) levels and associated cardiovascular (CV) diseases. However, the potential use of PCSK9 serum levels as a CV risk biomarker remains to be clarified.

METHODS

189 patients with severe carotid artery atherosclerosis undergoing carotid endarterectomy (CEA) and whose clinical records and serum sample aliquots for PCSK9 level measurement were available both directly before CEA and at 24-month follow-up were included in the present pilot study. The study endpoint was to determine whether PCSK9 serum levels prior to CEA would predict the occurrence of acute coronary syndromes (ACS) at 24-month follow-up.

RESULTS

PCSK9 serum levels were significantly accurate in predicting ACS at 24-month follow-up, as assessed by ROC curve analysis (AUC: 0.719 [95% CI 0.649-0.781]). According to the cut-off point indicated by Youden's index, PCSK9 values >431.3 ng/mL were correlated with a higher risk of ACS occurrence (Log Rank test, p = 0.0003). At Cox regression analysis, the predictive ability of high serum PCSK9 was confirmed also after adjustment for age, gender, baseline statin treatment and active smoking, dyslipidemia, and chronic coronary artery disease (HR 17.04 [95% CI 3.34-86.81]; p = 0.001).

CONCLUSIONS

High serum PCSK9 levels predict ACS occurrence at 24-month follow-up after CEA in patients with severe carotid artery stenosis. Larger clinical studies are needed to evaluate whether PCSK9 serum levels could be used towards predicting the risk of ACS in patients with advanced carotid atherosclerosis.

Circulating PCSK9 is lowered acutely following surgery

BACKGROUND

A decrease in serum low-density lipoprotein cholesterol (LDL-C) is well documented after acute stress. Plasma proprotein convertase subtilisin kexin 9 (PCSK9), which promotes degradation of low-density lipoprotein receptor (LDL-R) resulting in reduced plasma clearance of low-density lipoproteins (LDL) and an increase in serum LDL-C, would be predicted to decrease. Yet, a few studies have demonstrated an increase 1-8 days after acute stress. Our objective was to assess the earlier status of plasma PCSK9, within the first 24 hours of onset of stress.

METHODS

We measured serum lipids and plasma PCSK9 in 39 patients before and soon after an elective surgical procedure (abdominal aortic aneurysm (AAA) repair).

RESULTS

We observed an early decrease in PCSK9 following surgery, as well as a decrease in total cholesterol (TC), LDL-C, high-density lipoprotein cholesterol (HDL-C), non-high-density lipoprotein cholesterol (non-HDL-C) and triglycerides (TG).

CONCLUSION

Unlike other studies which showed an increase in PCSK9 after the onset of stress, our study detected a fall in PCSK9 following acute surgical stress. The observed difference is likely due to the earlier timing of PCSK9 measurement in our study. Further studies involving serial poststress measurements for several days are needed to determine whether PCSK9 behaves as an acute-phase reactant, whether it displays a biphasic response to acute stress, and whether changes in circulating PCSK9 are responsible for lipoprotein changes observed after surgical stress. (Clinical Trial Registration: ClinicalTrials.gov study ID NCT00493389).

Monocyte count at onset predicts poststroke outcomes during a 90-day follow-up

BACKGROUND

Acute ischaemic stroke (AIS) triggers both systemic and neurovascular inflammation, influencing poststroke recovery. In smokers with AIS, inflammation might be further upregulated, increasing ischaemia/reperfusion injury. Here, the predictive value of leucocyte and adhesion molecules levels on poststroke outcomes was investigated.

MATERIALS AND METHODS

A total of 89 patients with AIS (n = 30 smokers and n = 59 nonsmokers) were recruited and evaluated 1, 7 and 90 days after the onset to assess stroke severity by the National Institute of Health Stroke Scale (NIHSS) score as well as clinical recovery at 90 days by the modified Rankin Scale (mRS). Lesion volume was assessed by noncontrast computed tomography. Haematological parameters, blood chemistry and soluble adhesion molecules were measured.

RESULTS

Smokers experienced a more severe stroke and at a younger age with respect to nonsmokers, moreover, they had higher circulating levels of monocytes, neutrophils and soluble adhesion molecules. Baseline monocytes positively correlated with stroke severity and disability across all time points in the overall cohort. No correlation was shown between adhesion molecules and poststroke outcomes. A monocyte count >0·63 × 109 /L predicted worse stroke severity (defined as NIHSS ≥5) at day 90 independently of age, hypertension, thrombolysis and active smoking in the overall cohort. Similarly, a monocyte count >0·64 × 109 /L predicted poor neurological recovery at day 90 (defined as mRS > 2).

CONCLUSIONS

Smoker had more severe AIS and higher leucocytes and adhesion molecule levels. In the overall cohort, monocyte count was an independent predictor of worse poststroke outcome. Although larger trials are needed, monocyte count might be a cheap prognostic parameter in AIS.