Dyslipidaemia and mortality in COVID-19 patients: a meta-analysis.

BACKGROUND: The prevalence and prognostic implications of pre-existing dyslipidaemia in patients infected by the SARS-CoV-2 remain unclear. AIM: To assess the prevalence and mortality risk in COVID-19 patients with pre-existing dyslipidaemia. DESIGN: Systematic review and meta-analysis. METHODS: Preferred reporting items for systematic reviews and meta-analyses guidelines were followed in abstracting data and assessing validity. We searched MEDLINE and Scopus to locate all the articles published up to 31 January 2021, reporting data on dyslipidaemia among COVID-19 survivors and non-survivors. The pooled prevalence of dyslipidaemia was calculated using a random-effects model and presenting the related 95% confidence interval (CI), while the mortality risk was estimated using the Mantel-Haenszel random-effect models with odds ratio (OR) and related 95% CI. Statistical heterogeneity was measured using the Higgins I2 statistic. RESULTS: Of about 18 studies, enrolling 74 132 COVID-19 patients (mean age 70.6 years), met the inclusion criteria and were included in the final analysis. The pooled prevalence of dyslipidaemia was 17.5% of cases (95% CI: 12.3-24.3%, P < 0.0001), with high heterogeneity (I2 = 98.7%). Pre-existing dyslipidaemia was significantly associated with higher risk of short-term death (OR: 1.69, 95% CI: 1.19-2.41, P = 0.003), with high heterogeneity (I2 = 88.7%). Due to publication bias, according to the Trim-and-Fill method, the corrected random-effect ORs resulted 1.61, 95% CI 1.13-2.28, P < 0.0001 (one studies trimmed). CONCLUSION: Dyslipidaemia represents a major comorbidity in about 18% of COVID-19 patients but it is associated with a 60% increase of short-term mortality risk.

The inhibition of vascular smooth muscle cell migration by peptide and antibody antagonists of the alphavbeta3 integrin complex is reversed by activated calcium/calmodulin- dependent protein kinase II.

The migration of vascular smooth muscle cells (VSMCs) is thought to play a key role in the pathogenesis of many vascular diseases and is regulated by soluble growth factors/ chemoattractants as well as interactions with the extracellular matrix. We have studied the effects of antibodies to rat beta3 and human alphavbeta3 integrins on the migration of VSMCs. Both integrin antibodies as well as cyclic RGD peptides that bind to the vitronectin receptors alphavbeta3 and alphavbeta5 significantly inhibited PDGF-directed migration. This resulted in a reduction in the accumulation of inositol (1,4,5) trisphosphate and the activation of calcium/calmodulin-dependent protein kinase II (CamKII), an important regulatory event in VSMC migration identified previously. PDGF-directed VSMC migration in the presence of the anti-integrin antibodies and cyclic RGD peptides was restored when intracellular CamKII activity was elevated by either raising intracellular calcium levels with the ionophore, ionomycin, or infecting with a replication-defective recombinant adenovirus expressing a constitutively activated CamKII cDNA (AdCMV.CKIID3). Rescue of rat VSMCs was also observed in stably transfected cell lines expressing constitutively activated but not wild-type CamKII. These observations identify a key intermediate in the regulation of VSMC migration by outside-in signaling from the integrin alphavbeta3.

Intracellular signaling pathways required for rat vascular smooth muscle cell migration. Interactions between basic fibroblast growth factor and platelet-derived growth factor.

Intracellular signaling pathways activated by both PDGF and basic fibroblast growth factor (bFGF) have been implicated in the migration of vascular smooth muscle cells (VSMC), a key step in the pathogenesis of many vascular diseases. We demonstrate here that, while bFGF is a weak chemoattractant for VSMCs, it is required for the PDGF-directed migration of VSMCs and the activation of calcium/calmodulin-dependent protein kinase II (CamKinase II), an intracellular event that we have previously shown to be important in the regulation of VSMC migration. Neutralizing antibodies to bFGF caused a dramatic reduction in the size of the intracellular calcium transient normally seen after PDGF stimulation and inhibited both PDGF-directed VSMC migration and CamKinase II activation. Partially restoring the calcium transient with ionomycin restored migration and CamKinase II activation as did the forced expression of a mutant CamKinase II that had been "locked" in the active state by site-directed mutagenesis. These results suggest that bFGF links PDGF receptor stimulation to changes in intracellular calcium and CamKinase II activation, reinforcing the central role played by CamKinase II in regulating VSMC migration.

Atherosclerosis and the vascular biology of aging.

With advancing age, a series of structural, architectural and compositional modifications take place in the vasculature. The diameter of the vessels tends to increase, and thickening of intimal and medial layers is often observed. In the subendothelial space, blood-derived leukocytes and an increased amount of "activated" smooth muscle cells are present. Extracellular matrix accumulates and becomes particularly rich in glycosaminoglycans. Collagen content increases, while elastin fibers appear progressively disorganized, thinner, and frequently fragmented. These changes in the normal architecture of the vessel wall, that could be referred to as "the vasculopathy of aging", are likely to be the consequence of adaptive mechanisms to maintain normal conditions of flow, mechanical stress and/or wall tension. Although many of these features are similar to the histological findings of the atherosclerotic vessels, atherosclerosis and age-related "vasculopathy" are two distinct phenomena. Nonetheless, several experimental observations in animal models suggest a special link between "the vasculopathy of aging" and atherosclerotic disease, and suggest a particular predisposition of the old vessel to develop the atherosclerotic lesion. Compared to vessels from young animals, older ones show a greater reactivity to mechanical injury and to chronic insults. This may reflect changes in the biology of the vessels that are "intrinsic" to the aging process. Indeed, aging affects the function and responsiveness of the endothelium and vascular smooth muscle cells. Endothelial permeability is increased with age, while ability to produce vasoactive substances declines. Smooth muscle cells from old individuals show a growth advantage over the young ones, and display an increased ability to migrate toward chemoattractants. Moreover, the accumulation of advanced glycation end products (AGEs) occurring with aging can trigger a series of cellular events, such as cellular oxidative stress, expression of leukocyte adhesion molecules, endothelial transmigration of monocytes, and smooth muscle cell chemotaxis, all considered important prelesional events in the atherogenesis process. Taken together, the changes occurring with aging, while unproven to initiate lesion formation per se, are likely to accelerate the development of the atherosclerotic plaque and contribute to increased severity of this disease in the elderly.

Coronary heart disease risk factors in older persons.

In most Western nations, coronary heart disease (CHD) is the leading cause of death and one of the most important causes of physical disability in persons over 65 years of age. The importance of traditional CHD risk factors has been well documented in middle-aged populations, whereas their role in older populations is still under debate. This paper reviews the epidemiologic evidence from observational studies and randomized clinical trials that established risk factors for CHD predict level of risk of CHD, and identify high risk individuals among older men and women. Hypertension and cigarette smoking have been clearly associated with an increased risk of CHD events, and their modification has been proven to be highly effective in the primary and secondary prevention of CHD in older persons. For other highly prevalent risk factors, such as lipid abnormalities, obesity and physical inactivity, evidence of an independent association with CHD risk has been demonstrated by the majority of observational studies. However, definitive proof from controlled clinical trials of the beneficial effects of their modification is still lacking in the older population. The role of estrogen replacement therapy in the primary and secondary prevention of CHD in old women is still an open question. In evaluating the impact of these risk factors in older persons, elements such as comorbidity, frailty, and age-related changes in risk profile should also be taken into consideration. Given the complexity of the relationship between risk factors and multiple disease statuses, other important outcomes, such as osteoporosis, cancer, falls and physical disability, should be considered when evaluating the risks and benefits of risk factor modifications in older persons.

Regulation of vascular smooth muscle migration by mitogen-activated protein kinase and calcium/calmodulin-dependent protein kinase II signaling pathways.

Platelet-derived growth factor BB (PDGF BB) activation of the mitogen-activated protein kinases (MAPK), ERK1 and ERK2, has been shown to be necessary for mitogen-stimulated proliferation, but its role in regulating cell migration and its relationship to other chemotactic signaling events, such as CamKII activation, has not been defined. Using a modified Boyden chamber apparatus, we tested the effects of a selective inhibitor of the upstream activator of ERK1/2, MEK1, on PDGF-stimulated rat aortic vascular smooth muscle cells (VSMCs) alone and in combination with KN62, a selective inhibitor of CamKII. The MEK1 inhibitor, PD98059, caused a dose-dependent reduction in ERK2 activity that paralleled a decrease in migration up to 60%. This inhibition of migration was similar to that seen with KN62 and the combined effects of both inhibitors were non-additive. Although KN62 did not affect ERK2 activity in response to PDGF, PD98059 markedly inhibited PDGF-stimulated CamKII activity, suggesting that activation of CamKII by PDGF was dependent on ERK activity and that the effects of ERK inhibition on migration may be mediated through its ability to inhibit CamKII activity. To directly test this, VSMCs were infected with a recombinant adenovirus expressing constitutively activated CamKII. Infection reversed the inhibitory effects of KN62 on migration, but had no effect on the inhibition of migration seen with PD98059. These results suggest that while MAPK may act upstream of CamKII to control its activation in response to PDGF, it also regulates migration independently of CamKII activation.

Pulmonary hypertension associated with human immunodeficiency virus infection. Report of two cases and review of the literature.

Recent reports have suggested a possible association between HIV-1 infection and "idiopathic" pulmonary hypertension (PH), but the pathogenetic role of the viral agent has not been fully defined yet. We report the cases of two white males positive for human immunodeficiency virus type 1 (HIV-1) who presented with clinical and hemodynamic diagnosis of pulmonary hypertension. They were heterosexual, non-hemophiliac, heroin abusers with no signs of clinical AIDS. Neither one of the patients had opportunistic lung infections or any other cause of secondary pulmonary hypertension. In one case, peculiar clinical and electrocardiographic features of PH were associated with signs of thrombotic thrombocytopenic purpura (TTP). The association between PH and HIV-1 infection might be explained by a severe alteration of pulmonary endothelial cell homeostasis secondary to HIV-1 viral infection.

Heterozygous apolipoprotein C-II deficiency: lipoprotein and apoprotein phenotype and RsaI restriction enzyme polymorphism in the Apo C-IIPadova kindred.

Deficiency of apolipoprotein C-II (apo C-II), the cofactor for lipoprotein lipase, results in the familial chylomicronaemia syndrome characterized by severe hypertriglyceridaemia and fasting chylomicronaemia. To investigate the biochemical features of the heterozygous state for apo C-II deficiency, we characterized the lipid, lipoprotein and apolipoprotein profiles in 18 relatives of two affected individuals (brother and sister) homozygous for the apo C-IIPadova gene defect which results in the synthesis of a truncated 36 amino acid apolipoprotein. Carrier status was established in first degree relatives as well as in seven non-obligate heterozygotes by restriction enzyme analysis of amplified apo C-II genomic DNA using RsaI. No significant differences in lipid, lipoprotein and apo C-II levels were observed in heterozygotes when compared to unaffected family members. Thus, in this study, the carrier state was not associated with hypertriglyceridaemia or reduced plasma levels of apo C-II. However, analysis of amplified DNA from members of the apo C-IIPadova kindred by digestion with the enzyme RsaI, which identifies the mutant apo C-II, permitted the identification of heterozygous family members which could not be recognized by measuring either fasting triglycerides or plasma apo C-II levels. This study provides further evidence that apo C-II deficiency syndrome is a heterogeneous disease not only at the molecular level but also on the clinical ground with variable phenotypic expression in heterozygous individuals from different kindreds.

Role of calcium/calmodulin-dependent protein kinase II in the regulation of vascular smooth muscle cell migration.

BACKGROUND: The migration of vascular smooth muscle cells (VSMCs) is a key event in the pathogenesis of many vascular diseases. We have previously shown that VSMC migration in response to platelet-derived growth factor (PDGF) is suppressed when cultured cells are growth-arrested and induced to differentiate. The present study was undertaken to elucidate the mechanism of this suppression. METHODS AND RESULTS: While both proliferating and growth-arrested VSMCs upregulated expression of the immediate early response genes, c-fos and JE (monocyte chemoattractant protein 1), growth-arrested VSMCs exhibited much smaller changes in intracellular calcium in response to PDGF and failed to activate the calcium/calmodulin-dependent protein kinase II (CaM kinase II). Blocking calcium-calmodulin interactions (50 mumol/L W7) or the activation of CaM kinase II (10 mumol/L KN62) in proliferating cells blocked their migration by more than 90%, whereas inhibition of protein kinase C activation had no significant effect on migration. Pretreatment of growth-arrested VSMCs with the calcium ionophore ionomycin resulted in an approximately 2.5-fold activation of CaM kinase II and increased migration of growth-arrested cells to 84 +/- 6% that of proliferating cells. These effects of ionomycin were blocked by inhibitors of CaM kinase II. Constitutively activated (ie, calcium/calmodulin-independent) CaM kinase II introduced by gene transfection into growth-arrested cells significantly increased migration toward PDGF from < 20% to > 70% that of proliferating cells. CONCLUSIONS: These results demonstrate that activation of CaM kinase II is required for VSMC migration, that its activation in response to PDGF is suppressed in growth-arrested VSMCs, and that this suppression of CaM kinase II activation is responsible, in large part, for the failure of growth-arrested VSMCs to migrate toward PDGF.

Migration of cultured vascular smooth muscle cells through a basement membrane barrier requires type IV collagenase activity and is inhibited by cellular differentiation.

The migration of vascular smooth muscle cells (VSMCs) from the tunica media to the neointima is a key event in the development and progression of many vascular diseases and a highly predictable consequence of mechanical injury to the blood vessel. In vivo, VSMCs are surrounded by and embedded in a variety of extracellular matrices (ECMs) that must be traversed during migration. One of the principal barriers to cell movement in the intact vessel is the basement membrane (BM) that surrounds each VSMC and separates the VSMC-containing medial cell layer from the endothelium. We have used a Boyden chamber to monitor the ability of VSMCs to degrade a BM barrier as they migrate toward a chemoattractant and to define the role of extracellular proteases in this process. We show that cultured VSMCs can migrate across a BM barrier and that this ability was dependent on the phenotypic state of the cell. VSMCs maintained in a proliferating or "synthetic" state readily migrated across a BM toward a chemoattractant, whereas the migration of serum-starved/differentiated VSMCs was suppressed by > 80% (P < .001). By use of a number of peptides that inhibit matrix metalloproteinase (MMP) activity, the migration of proliferating VSMCs across the BM barrier was inhibited by > 80% (P < .0001), whereas migration that occurred in the absence of the barrier was unaffected. Northern blotting and zymographic analyses indicated that 72-kD type IV collagenase (MMP2) was the principal MMP expressed and secreted by these cells. Accordingly, antisera capable of selectively neutralizing MMP2 activity also inhibited VSMC migration across the barrier without significantly affecting the migration of VSMCs in the absence of the barrier. Finally, MMP2 activity was also regulated by the phenotypic state of the cells in that MMP2 activity expressed by serum-starved/differentiated VSMCs was < 5% of that measured in proliferating VSMCs. Extrapolating to the in vivo situation in which VSMCs reside in an ECM composed of various BM barriers, these results suggest that VSMC migration in vivo may be dependent on MMP2 activity. That activity, in turn, could be regulated by the phenotypic state of VSMCs and increase as these cells undergo the transition from a quiescent and differentiated state to that of a dedifferentiated, proliferating, and motile phenotype after injury to the vessel.

Homozygous familial hypobetalipoproteinemia. Increased LDL catabolism in hypobetalipoproteinemia due to a truncated apolipoprotein B species, apo B-87Padova.

Mutations on the apolipoprotein (apo) B gene that interfere with the full-length translation of the apoB molecule are associated with familial hypobetalipoproteinemia (FHBL), a disease characterized by the reduction of plasma apoB and LDL cholesterol. In this report, we describe an FHBL kindred carrying a unique truncated apoB form, apoB-87Padova. Sequence analysis of amplified genomic DNA identified a single G deletion at nucleotide 12032, which shifts the translation reading frame and causes a termination at amino acid 3978. Two homozygous subjects and seven heterozygous relatives were studied. Although homozygous individuals had only trace amounts of LDL, they were virtually free from the symptoms typical of homozygous FHBL subjects. We investigated the in vivo turnover of radiolabeled normal apoB-100 LDL and apoB-87 LDL in one homozygous patient and two normal control subjects. ApoB-87 LDL showed a similar metabolism in all three subjects, with a fractional catabolic rate more than double that of normal LDL. The rate of entry of apoB-87 in the LDL compartment was also markedly decreased compared with normal apoB-100. The increased in vivo catabolism of apoB-87 LDL was paralleled in vitro by a 2.5-fold increased ability of these particles to inhibit the uptake and degradation of normal apoB-100 LDL by normal human cultured fibroblasts. These results indicate that apoB-87 LDL has an enhanced ability to interact with the LDL receptor, the increased apoB catabolism contributes to the hypobetalipoproteinemia and may explain the mild expression of the disease in the two homozygous individuals.

Adenovirus-mediated gene transfer of the human tissue inhibitor of metalloproteinase-2 blocks vascular smooth muscle cell invasiveness in vitro and modulates neointimal development in vivo.

BACKGROUND: Endovascular injury induced by balloon withdrawal leads to the increased activation of matrix metalloproteinases (MMPs) in the vascular wall, allowing smooth muscle cells (SMCs) to digest the surrounding extracellular matrix (ECM) and migrate from the media into the intima. The objective of this study was to examine the effects of a replication-deficient adenovirus carrying the cDNA for human tissue inhibitor of metalloproteinase-2 (AdCMV.hTIMP-2) on SMC function in vitro and neointimal development in the injured rat carotid artery. METHODS AND RESULTS: Infection of cultured rat aortic SMCs at a multiplicity of infection of 100 with AdCMV.hTIMP-2 resulted in high-level expression of hTIMP-2 mRNA and protein secretion into the medium. Conditioned media (CM) from AdCMV. hTIMP-2-infected but not control virus (AdCMV.null or AdCMV. betagal)-infected SMCs inhibited MMP-2 activity on gelatin zymograms as well as the chemoattractant-directed migration of SMCs across reconstituted basement membrane proteins in the Boyden chamber assay. In contrast, AdCMV.hTIMP-2 CM had no effect on chemoattractant-directed migration of SMCs occurring in the absence of an ECM barrier or on the proliferation of cultured neointimal SMCs. Delivery of AdCMV.hTIMP-2 (2.5x10(9) pfu) to the carotid artery wall at the time of balloon withdrawal injury inhibited SMC migration into the intima by 36% (P<0.05) at 4 days and neointimal area by 53% (P<0.01) at 8 days and by 12% (P=NS) at 21 days after injury. AdCMV.hTIMP-2 had no effect on medial area. CONCLUSIONS: Adenovirus-mediated hTIMP-2 gene transfer inhibits SMC invasiveness in vitro and in vivo and delays neointimal development after carotid injury.

Increased expression of membrane-type matrix metalloproteinase and preferential localization of matrix metalloproteinase-2 to the neointima of balloon-injured rat carotid arteries.

BACKGROUND: Remodeling of the injured vascular wall is dependent on the action of several extracellular proteases. Previous studies have shown that expression of matrix metalloproteinases (MMP-2 and MMP-9) is upregulated after vascular injury and that MMP-2 is required for the migration of cultured vascular smooth muscle cells across complex extracellular matrix barriers. The present study examined changes in the expression of membrane-type metalloproteinase (MT-MMP-1), a putative regulator of MMP-2, in the tissue localization of MMP-2, and in the expression of activated and latent forms of MMP-2 and the tissue inhibitor of metalloproteinases, TIMP-2, in rat carotid arteries subjected to balloon catheter injury. METHODS AND RESULTS: MT-MMP-1 mRNA levels increased sixfold after 3 days of injury, coinciding with an increase in MMP-2 activation assessed by gelatin zymography. Western blotting and gelatin zymography showed an increase in MMP-2 protein levels beginning 5 to 7 days after injury; immunocytochemistry and Western blotting showed that the increase occurred preferentially in the developing neointima. CONCLUSIONS: These results show that increased expression of MT-MMP-1 and activation of MMP-2 occurs early after injury to the rat carotid artery and that at later times MMP-2 is preferentially localized to the developing neointima.