Apolipoprotein E, periodontal disease and the risk for atherosclerosis: a review

Role of macrophage polarization in periodontitis promoting atherosclerosis

Periodontitis is a chronic inflammatory destructive disease occurring in periodontal supporting tissues. Atherosclerosis(AS) is one of the most common cardiovascular diseases. Periodontitis can promote the development and progression of AS. Macrophage polarization is closely related to the development and progression of the above two diseases, respectively. The purpose of this animal study was to evaluate the effect of periodontitis on aortic lesions in atherosclerotic mice and the role of macrophage polarization in this process. 45 ApoE-/-male mice were randomly divided into three groups: control (NC), atherosclerosis (AS), and atherosclerosis with periodontitis (AS + PD). Micro CT, serological testing and pathological testing(hematoxylin-eosin staining, oil red O staining and Masson staining) were used for Evaluate the modeling situation. Immunohistochemistry(IHC) and immunofluorescence(IF) were performed to evaluate macrophage content and macrophage polarization in plaques. Cytokines associated with macrophage polarization were analyzed using quantitative real-time polymerase chain reaction(qRT-PCR) and enzyme-linked immunosorbent assay(Elisa). The expression of macrophages in plaques was sequentially elevated in the NC, AS, and AS + PD groups(P < 0.001). The expression of M1 and M1-related cytokines showed the same trend(P < 0.05). The expression of M2 and M2-related cytokines showed the opposite trend(P < 0.05). The rate of M1/M2 showed that AS + PD > AS > NC. Our preliminary data support that experimental periodontitis can increase the content of macrophage in aortic plaques to exacerbate AS. Meanwhile, experimental periodontitis can increase M1 macrophages, and decrease M2 macrophages, increasing M1/M2 in the plaque.

Smoking and salivary microbiota: a cross-sectional analysis of an Italian alpine population

The oral microbiota plays an important role in the exogenous nitrate reduction pathway and is associated with heart and periodontal disease and cigarette smoking. We describe smoking-related changes in oral microbiota composition and resulting potential metabolic pathway changes that may explain smoking-related changes in disease risk. We analyzed health information and salivary microbiota composition among 1601 Cooperative Health Research in South Tyrol participants collected 2017-2018. Salivary microbiota taxa were assigned from amplicon sequences of the 16S-V4 rRNA and used to describe microbiota composition and predict metabolic pathways. Aerobic taxa relative abundance decreased with daily smoking intensity and increased with years since cessation, as did inferred nitrate reduction. Former smokers tended to be more similar to Never smokers than to Current smokers, especially those who had quit for longer than 5 years. Cigarette smoking has a consistent, generalizable association on oral microbiota composition and predicted metabolic pathways, some of which associate in a dose-dependent fashion. Smokers who quit for longer than 5 years tend to have salivary microbiota profiles comparable to never smokers.

Effect of atorvastatin on subclinical atherosclerosis in virally-suppressed HIV-infected patients with CMV seropositivity: a randomized double-blind placebo-controlled trial

Background: Persistent immune activation and inflammation in HIV-infection are linked to excess cardiovascular risk and other non-communicable diseases. Periodic asymptomatic CMV-reactivity in HIV infected patients over a lifetime may contribute to non-AIDS defining morbidity. Despite undetectable levels of HIV and CMV, these patients continue to have increased levels of biomarkers and immune activations. Statin administration is thought to reduce subclinical atherosclerosis by decreasing LDL-C levels. It may also add beneficial effects against CMV infection. Methods: We are conducting a double-blind placebo-controlled trial in which patients are randomized to receive either atorvastatin or placebo with a ratio of 1:1. This trial aims to study the effect of atorvastatin in statin-naive virally-suppressed HIV-infected patients with stable ART and CMV seropositivity on carotid intima media thickness (CIMT), tool that evaluates subclinical atherosclerosis. The study recruits 80 patients at HIV integrated care unit of Cipto Mangunkusumo hospital. All eligible subjects have CIMT evaluation as primary outcome, along with flow mediated vasodilatation (FMD), liver fibrosis and steatosis evaluation, fasting lipid, neurocognitive test, community periodontal index (CPI), and residual immune activation as secondary outcomes in 48 weeks. Ethics and dissemination: This study has received an ethical approval from Health Research Ethics Commitee-Universitas Indonesia and Cipto Mangunkusumo Hospital. Before joining the study, all participants fill in an informed consent form. At the end of study analysis, the trial results will be published and disseminated in peer-reviewed journals. Discussion: The main purpose of our study is to evaluate the effect of atorvastatin administration on CIMT changes in statin naïve virally suppressed HIV-infected patients with stable ART and CMV seropositivity Registration: ClinicalTrials.gov ID NCT04101136; registered on 24 September 2019.

Effect of atorvastatin on subclinical atherosclerosis in virally-suppressed HIV-infected patients with CMV seropositivity: a randomized double-blind placebo-controlled trial

Background: Persistent immune activation and inflammation in HIV-infection are linked to excess cardiovascular risk and other non-communicable diseases. Periodic asymptomatic CMV-reactivity in HIV infected patients over a lifetime may contribute to non-AIDS defining morbidity. Despite undetectable levels of HIV and CMV, these patients continue to have increased levels of biomarkers and immune activations. Statin administration is thought to reduce subclinical atherosclerosis by decreasing LDL-C levels. It may also add beneficial effects against CMV infection. Methods: We are conducting a double-blind placebo-controlled trial in which patients are randomized to receive either atorvastatin or placebo with a ratio of 1:1. This trial aims to study the effect of atorvastatin in statin-naive virally-suppressed HIV-infected patients with stable ART and CMV seropositivity on carotid intima media thickness (CIMT), tool that evaluates subclinical atherosclerosis. The study recruits 80 patients at HIV integrated care unit of Cipto Mangunkusumo hospital. All eligible subjects have CIMT evaluation as primary outcome, along with flow mediated vasodilatation (FMD), liver fibrosis and steatosis evaluation, fasting lipid, neurocognitive test, community periodontal index (CPI), and residual immune activation as secondary outcomes in 48 weeks. Ethics and dissemination: This study has received an ethical approval from Health Research Ethics Commitee-Universitas Indonesia and Cipto Mangunkusumo Hospital. Before joining the study, all participants fill in an informed consent form. At the end of study analysis, the trial results will be published and disseminated in peer-reviewed journals. Discussion: The main purpose of our study is to evaluate the effect of atorvastatin administration on CIMT changes in statin naïve virally suppressed HIV-infected patients with stable ART and CMV seropositivity Registration: ClinicalTrials.gov ID NCT04101136; registered on 24 September 2019.

Association of Apolipoprotein E4-related Microvascular Disease in the Alzheimer's Disease Hippocampal CA1 Stratum Radiatum

Current data suggest a hypothesis of vascular pathogenesis for the development and progression of Alzheimer's disease (AD). To investigate this, we studied the association of apolipoprotein E4 (APOE4) gene on microvessels in human autopsy-confirmed AD with and without APOE4, compared with age/sex-matched control (AC) hippocampal CA1 stratum radiatum. AD arterioles (without APOE4 gene) had mild oxidative stress and loss of vascular endothelial growth factor (VEGF) and endothelial cell density, reflecting aging progression. In AD + APOE4, an increase in strong oxidative DNA damage marker 8-hydroxy-2'-deoxyguanosine (8-OHdG), VEGF, and endothelial cell density were associated with increased diameter of arterioles and perivascular space dilation. In cultured human brain microvascular cells (HBMECs), treatment of ApoE4 protein plus amyloid-β (Aβ) oligomers increased superoxide production and the apoptotic marker cleaved caspase 3, sustained hypoxia inducible factor-1α (HIF-1α) stability that was associated with an increase in MnSOD, VEGF, and cell density. This cell over-proliferation was inhibited with the antioxidants N-acetyl cysteine and MnTMPyP, the HIF-1α inhibitor echinomycin, the VEGFR-2 receptor blocker SU1498, the protein kinase C (PKC) ε knock-down (KD) and the extracellular signal-regulated kinase 1/2 (ERK) inhibitor FR180204. The PKCε KD and echinomycin decreased VEGF and/or ERK. In conclusion, AD capillaries and arterioles in hippocampal CA1 stratum radiatum of non-APOE4 carriers are related with aging, while those in APOE4 carriers with AD are related with pathogenesis of cerebrovascular disease.

Association of Different Combinations of ALDH2 rs671, APOE rs429358, rs7412 Polymorphisms with Hypertension in Middle-Aged and Elderly People: A Case-Control Study

Background

Hypertensive patients have a younger trend, and studies on the role of genetic factors in hypertension susceptibility have been inconsistent. Aldehyde dehydrogenases 2 (ALDH2) and apolipoprotein E (APOE) are involved in the pathophysiological processes of hypertension. To investigate the relationship of ALDH2 and APOE polymorphisms with hypertension in middle-aged (30-59 years old) and elderly (≥60 years old) persons.

Methods

Two thousand six hundred and ten hypertensive patients and 1921 controls were included (between 30 and 100 years old). The genotypes of common polymorphisms in APOE and ALDH2 genes (APOE rs429358, rs7412, and ALDH2 rs671) of the subjects were analyzed by polymerase-chain reaction (PCR)-microarray. Statistical analyses (Student's t-test, Mann-Whitney U-test, χ ² test, and logistic regression analysis) were performed with SPSS v21.0.

Results

There were 4531 participants (66.60 ± 12.10 years old) in this study, including 3057 (67.5%) males and 1474 (32.5%) females. There were no significant differences in distributions of ALDH2 rs671, APOE rs429358/rs7412 genotypes and alleles between hypertensive patients and controls. Persons with ALDH2 rs671 G/A or A/A genotype were less likely to have hypertension (G/A+A/A vs G/G: gender-, age-, smoking-, and drinking-adjusted OR 0.885, 95% CI 0.785-0.997, P=0.045), while ALDH2 rs671 A/A+APOE rs429358 or rs7412 wild-type genotype may decrease the risk of hypertension. In middle-aged group, ALDH2 rs671 G/A+APOE rs429358 T/C carriers (adjusted OR 0.547, 95% CI 0.350-0.856, P=0.008), and ALDH2 rs671 A/A+APOE rs7412 C/C genotypes (adjusted OR 0.567, 95% CI 0.361-0.891, P=0.014) were less likely to have hypertension. In elderly group, APOE rs7412 T/T carriers were more likely to have hypertension (rs671 T/T vs C/C: adjusted OR 4.755, 95% CI 1.075-21.027, P=0.040; rs671 T/T vs C/C or C/T: adjusted OR 4.734, 95% CI 1.071-20.928, P=0.040).

Conclusion

Polymorphism-polymorphism interactions of ALDH2 rs671 and APOE rs429358/rs7412 may effect on hypertension susceptibility. Different genotypes comparison shows different roles in middle-aged and elderly people, respectively.

Apolipoprotein E Gene Polymorphism and Coronary Artery Disease Risk Among Patients in Northwest China

PURPOSE

The association between apolipoprotein E (ApoE) gene polymorphisms and the risk of coronary artery disease (CAD) among different populations has been assessed in numerous previous studies, but the results remain inconclusive. The present study aimed to determine the role of ApoE genotypes in CAD risk and the interrelationships between lipid profiles and ApoE alleles and genotypes among the population of northwest China.

PATIENTS AND METHODS

This study was performed on 308 patients with CAD and 308 control participants. ApoE gene polymorphism was analysed using the polymerase chain reaction and hybridization.

RESULTS

The findings indicated that the frequencies of ε3/ε4 genotype and ε4 allele frequency were significantly higher in patients with CAD than in the control participants. ε2 carriers had significantly lower total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C) and triglycerides (TG) levels than did ε3 or ε4 carriers among the control participants. However, our study found no significant differences in plasma lipoprotein levels between ɛ2, ɛ3 and ɛ4 carriers in patients with CAD. Moreover, ε4 carriers had significantly higher ApoB, ApoB/ApoA-I levels and significantly lower ApoE levels in both patients with CAD and control participants. ε4 allele presence was associated with a nearly two-fold higher CAD risk. After adjusting for other established risk factors, ε4 allele was an independent risk factor for CAD. After stratified by age (≤ 60 years and >60 years), ε4 allele was indicated to increase the CAD risk 3.3-fold in elderly patients with CAD, but not in young patients with CAD. After stratified by sex, ε4 allele was not a risk factor in females and males patients with CAD.

CONCLUSION

This study provides evidence that the ε4 allele, drinking, smoking, hypertension, and TG and ApoE levels are independent risk factor for CAD among patients in northwest China.

ApoE4 increases susceptibility to stress-induced age-dependent depression-like behavior and cognitive impairment

Though apolipoprotein E ε4 (APOE ε4) is a major genetic risk factor for late-onset Alzheimer's disease, its association with depression remains controversial. In present study, 3-month-old and 8-month-old apoE-targeted replacement (TR) mice were both subjected to chronic unpredictable mild stress (CUMS) for six weeks. The results showed that 8-month apoE4-TR mice were more susceptible to the CUMS-induced depression-like behaviors and cognitive impairment than age-matched apoE3-TR mice. Stress induced a loss of GABAergic neurons and decline of Reelin level in the prefrontal cortex (PFC) and in the dentate gyrus (DG) of the hippocampus in both 3-month-old and 8-month-old apoE-TR mice, which were more pronounced in the 8-month-old apoE4-TR mice. Of note, stress decreased the level of PSD95 in the hippocampal synaptosome and increased the phosphorylation of N-methyl-D-aspartate receptor subunit GluN2B in the hippocampus of 8-month-old apoE4-TR mice. However, the expressions of apoE and apoE receptor 2 (apoER2) were not affected by stress. The study provides rodent evidence that APOE ε4 may increase the risk of depression and dementia in the elderly population by impairing the GABAergic signaling pathway and enhancing the GluN2B phosphorylation, which signifies that GluN2B inhibitors in clinical settings may be effective for elderly depression patients with APOE4 carriers.

Methylmercury chronic exposure affects the expression of DNA single-strand break repair genes, induces oxidative stress, and chromosomal abnormalities in young dyslipidemic APOE knockout mice

Mercury (Hg) is one of the most toxic environmental pollutants, especially when methylated, forming methylmercury (MeHg). MeHg affects DNA repair, increases oxidative stress, and predisposes to cancer. MeHg neurotoxicity is well-known, but recently MeHg-associated cardiovascular effects were recognized. This study evaluated circulating lipids, oxidative stress, and genotoxicity after MeHg-chronic exposure (20 mg/L in drinking water) in C57BL/6J wild-type and APOE knockout (ko) mice, the latter, being spontaneously dyslipidemic. Experimental mice were assigned to four groups: non-intoxicated and MeHg-intoxicated wild-type mice and non-intoxicated and MeHg-intoxicated APOE ko mice. Plasma levels of triglycerides, total cholesterol (TC), HDL, and LDL were analyzed. Liver lipid peroxidation and splenic gene expression of xeroderma pigmentosum complementation groups A, C, D, and G (XPA, XPC, XPD, and XPG), X-ray repair cross-complementing protein 1 (XRCC1), and telomerase reverse transcriptase (TERT) were measured. Fur Hg levels confirmed chronic MeHg intoxication. MeHg exposure raises TC levels both in wild-type and APOE ko mice. HDL and LDL-cholesterol levels were increased only in the MeHg-challenged APOE ko mice. MeHg increased liver lipid peroxidation, regardless of the genetic background. Unintoxicated APOE ko mice showed higher expression of TERT than all other groups. APOE deficiency increases XPA expression, regardless of MeHg intoxication. Furthermore, MeHg-intoxicated mice had more cytogenetic abnormalities, effect which was independent of APOE deficiency. More studies are needed to dissect the interactions between circulating lipids, MeHg intoxication, and DNA-repair pathways even at young age, interactions that likely play critical roles in cell senescence and the risk for chronic disorders later in life.

Global research trends of Apolipoprotein E in central nervous system: A scientometric analysis

Apolipoprotein E (apoE, protein; APOE, gene) involves in cholesterol recycling and redistribution by mediating lipoprotein pathways unique to central nervous system (CNS), which is a potential therapeutic target for diseases. We visually analyzed the research hotspots of APOE related to CNS in this work, by scientometric analysis from the Web of Science Core Collection (WOSCC) database over the past two decades. A total of 25,719 references of "APOE" and 836 references of "APOE in CNS" were retrieved from the WOSCC on October 26, 2020, and then VOSviewer 1.6.15, Citespace 5.7.R2 were used for visual analysis. Over the last two decades, the research on the field of APOE in CNS is not faddish. Although many funds, organizations, and scholars were affiliated in this field, organizations and scholars, especially the top teams in this field, still lacked close cooperation with other teams around the world. Few articles with high citations had been published in the last decade, but recent studies still lacked scale and breakthrough, and the keywords associated with APOE appeared more outdated. However, the current researches have not fully elucidated the crosstalk between APOE and neuroinflammation in CNS, some new ideas may rekindle the research enthusiasm of scholars. Although the field of APOE in CNS appeared more outdated. Based on keyword analysis, we hypothesized new ideas for further investigation of neuroinflammation would light the interest of APOE in CNS for the scholars. The crosstalk between ApoE and inflammasome may be the focus of future researches. How APOE modulates the time course or intensity of the inflammasome activation, inflammatory response (proinflammatory or anti-inflammatory), and pathological process of CNS disease deserves future attention in both basic and clinical studies. More apoE/APOE-targeted pharmacological interventions will be available for preclinical experiments and clinical trials and bring hope for patients with CNS diseases.

Association of APOE polymorphisms with lipid-lowering efficacy of statins in atherosclerotic cardiovascular diseases

Introduction: Apolipoprotein E (APOE) gene is a promising candidate for the diagnosis of hyperlipoproteinaemia and atherosclerosis. Polymorphisms in APOE have been reported to result in differential efficacies of statins in atherosclerotic cardiovascular diseases. Method: We classified APOE genotypes of 225 patients treated with atorvastatin and analysed the relationship between genotypes and blood lipid levels. Results: The baseline levels of total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) were significantly lower in APOE ε4 than APOE ε3 carriers. Levels of TC and LDL-C decreased significantly after 1 month of atorvastatin treatment. Statins have a higher significant effect in reducing TC and LDL-C levels in APOE ε4 genotype. Conclusion: Polymorphism in APOE is related to the efficacy of atorvastatin in reducing the levels of TC and LDL-C. Keywords: Apolipoprotein E, lipid-lowering efficacy, polymorphism, statin, total cholesterol

Periodontitis and Cytomegalovirus Associate With Atherosclerosis Among HIV Patients After 5 Years on ART

OBJECTIVES

Atherosclerosis has been linked with periodontitis in the general population and with persistent immune activation and a high burden of cytomegalovirus (CMV) in HIV patients responding to antiretroviral therapy (ART). Here, we assess risk factors for cardiovascular changes in younger HIV patients representative of patient populations in Asia.

STUDY DESIGN

HIV-infected adults (n = 82) with <200 CD4 T-cells/μl were examined as they began ART at Cipto Mangunkusumo Hospital, Jakarta, and after 3 months. 32 patients were re-assessed after 5 years, alongside 32 age-matched healthy controls.

METHODS

We assessed the community periodontal index of treatment needs, carotid -thickness (cIMT), plasma markers of immune activation (using commercial enzyme-linked immunosorbent assay) and CMV antibodies by in-house enzyme-linked immunosorbent assay.

RESULTS

Periodontitis persisted in 16/32 patients after 5 years and was potentiated by greater age (P = 0.03) and poor oral hygiene (P = 0.05), with no effect of smoking, pulmonary tuberculosis, oral candidiasis, or low CD4 T-cell counts (P > 0.05). After 5 years on ART, right and left cIMT were greater in HIV patients with periodontitis (P = 0.02, 0.006, respectively). Moreover, cIMT values were higher in patients with periodontitis (P = 0.05-0.01) than in equivalent controls. Simple linear regressions showed that patients with periodontitis had greater right (P = 0.01) and left (P = 0.004) cIMT than those without periodontitis. Multiple linear regressions showed that periodontitis and CMV antibody levels optimally predicted poor right and left cIMT (Adjusted R = 0.36, P = 0.0013; Adjusted R = 0.40, P = 0.001, respectively).

CONCLUSIONS

Our data identify periodontitis and CMV as independent predictors of atherosclerosis in young adult HIV patients.

Apolipoprotein E polymorphism influences orthotopic liver transplantation outcomes in patients with hepatitis C virus-induced liver cirrhosis

BACKGROUND

Hepatitis C virus (HCV) infection is responsible for a chronic liver inflammation, which may cause end-stage liver disease and hepatocellular carcinoma. Apolipoprotein E (protein: ApoE, gene: APOE), a key player in cholesterol metabolism, is mainly synthesized in the liver and APOE polymorphisms may influence HCV-induced liver damage.

AIM

To determine whether APOE alleles affect outcomes in HCV-infected patients with liver cirrhosis following orthotopic liver transplantation (OLT).

METHODS

This was a cohort study in which 179 patients, both genders and aged 34-70 years, were included before or after (up to 10 years follow-up) OLT. Liver injury severity was assessed using different criteria, including METAVIR and models for end-stage liver disease. APOE polymorphisms were analyzed by quantitative real-time polymerase chain reaction.

RESULTS

The APOE3 allele was the most common (67.3%). In inflammation severity of biopsies from 89 OLT explants and 2 patients in pre-transplant, the degree of severe inflammation (A3F4, 0.0%) was significantly less frequent than in patients with minimal and moderate degree of inflammation (≤ A2F4, 16.2%) P = 0.048, in patients carrying the APOE4 allele when compared to non-APOE4. In addition, a significant difference was also found (≤ A2F4, 64.4% vs A3F4, 0.0%; P = 0.043) and (A1F4, 57.4% vs A3F4, 0.0%; P = 0.024) in APOE4 patients when compared to APOE3 carriers. The fibrosis degree of the liver graft in 8 of 91 patients and the lack of the E4 allele was associated with more moderate fibrosis (F2) (P = 0.006).

CONCLUSION

Our results suggest that the E4 allele protects against progression of liver fibrosis and degree of inflammation in HCV-infected patients.

The association study of Apolipoprotein E polymorphisms and chronic obstructive pulmonary disease in the Chinese population: A case-control study

Chronic obstructive pulmonary disease (COPD) patients have increased cardiovascular morbidity and mortality. Apolipoprotein E (ApoE) is involved in chronic inflammation which is the common characteristic of emphysema and cardiovascular disease. ApoE polymorphisms are associated with cardiovascular disorders and atherosclerosis. There is no report about the association between ApoE polymorphism and COPD.A total of 480 COPD patients and 322 controls who were unrelated Chinese Han individuals were enrolled. Rs429358 and rs7412 were genotyped and the associations between ApoE polymorphisms and COPD risk were analyzed by logistic regression analysis. Online software SHEsis were applied to perform linkage disequilibrium (LD) and haplotypes analysis. The interactions of ApoE and environmental factor on COPD susceptibility was analyzed by software MDR3.0.2.No significant association was found between rs429358, rs7412 and COPD under different genetic models. Rs429358 and smoking formed the best model in the MDR analysis. The frequency of E2/E2 phenotype was the lowest in 2 groups. E3/E3 was the most common phenotype, accounting for 69.8% of COPD patients and 68.9% of controls. No statistically difference was identified between the cases and controls under different phenotypes.This was the first genetic association study between ApoE and COPD. No positive association was found in the Chinese Han population. Rs429358 and smoking status existed significant interaction, indicating that both of ApoE and smoking may be involved in the development of COPD disease.

Network Protein Interaction in Parkinson's Disease and Periodontitis Interplay: A Preliminary Bioinformatic Analysis

Recent studies supported a clinical association between Parkinson's disease (PD) and periodontitis. Hence, investigating possible interactions between proteins associated to these two conditions is of interest. In this study, we conducted a protein-protein network interaction analysis with recognized genes encoding proteins with variants strongly associated with PD and periodontitis. Genes of interest were collected via the Genome-Wide Association Studies (GWAS) database. Then, we conducted a protein interaction analysis, using the Search Tool for the Retrieval of Interacting Genes/Proteins (STRING) database, with a highest confidence cutoff of 0.9 and sensitivity analysis with confidence cutoff of 0.7. Our protein network casts a comprehensive analysis of potential protein-protein interactions between PD and periodontitis. This analysis may underpin valuable information for new candidate molecular mechanisms between PD and periodontitis and may serve new potential targets for research purposes. These results should be carefully interpreted, giving the limitations of this approach.

Apolipoprotein E Effects on Mammalian Ovarian Steroidogenesis and Human Fertility

Apolipoprotein E (ApoE) is a glycoprotein consisting of 299 amino acids, highly produced in the mammalian ovaries. The main function of the ApoE is to transport cholesterol from the peripheral tissues to be metabolized in the liver. In humans, the ApoE gene is polymorphic, with three alleles in a single chromosome-19 locus: APOE2, APOE3, and APOE4. ApoE has also been implicated in cholesterol transport within ovarian follicles to regulate steroidogenesis. Ovarian thecal and granulosa cell cholesterol uptake requires ApoE either by participating in the lipoprotein-receptor complex or lipid endocytosis. In this review, we summarize ApoE role on mammalian ovarian steroidogenesis and on human fertility and discuss recent findings of ApoE4 as an antagonistic pleiotropy gene under adverse environments.

Periodontitis and circulating blood cell profiles: a systematic review and meta-analysis

Periodontitis is a chronic inflammatory disease with local and systemic implications. Evidence suggests consistent hematologic changes associated with periodontitis. Our aim was to critically appraise the available evidence on hemogram, leukogram, and thrombogram alterations in otherwise healthy patients suffering from periodontitis when compared with controls. For this systematic review (SR), we searched MEDLINE, Web of Science, EMBASE, and the Cochrane Library (CENTRAL) for studies published up to June 2020. Both observational and interventional studies with baseline standard hematologic levels were included. Outcomes of interest were baseline hemogram, leukogram, and thrombogram values and the impact of periodontitis treatment on these outcomes. Upon risk of bias assessment, data extraction and both qualitative and quantitative (standardized mean differences) analyses were performed. Random-effects meta-analyses were performed to provide pooled estimates. The Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines were followed (PROSPERO Reg. No. CRD42020164531). A total of 45 studies, eight intervention and 37 case-control studies, were identified after the final search of 3,012 titles. Following quality assessment, 43 articles were deemed to have low risk of bias, and two articles moderate risk. Meta-analyses confirmed that periodontitis was associated with both white and red cell lineages. Severe chronic periodontitis was associated with greater white blood cell counts (mean difference [MD] = 0.53, 95% confidence interval [CI]: 0.26-0.79) when compared with controls. Periodontitis was associated with a larger number of neutrophils (MD = 7.16%, 95% CI: 5.96-8.37) and lower mean platelet volume (MD = 0.30 fL, 95% CI: 0.49 to -0.10) compared with healthy participants. Nonsurgical periodontal treatment was associated with a decrease in white blood cell (WBC) levels (MD = 0.28 10⁹/L, 95% CI: -0.47 to -0.08) in patients with chronic periodontitis. Periodontitis is associated with hematologic changes (Strength of Recommendation Taxonomy [SORT] A recommendation). Higher WBC levels, higher neutrophil levels, higher erythrocyte sedimentation rate, and lower mean platelet volumes are the most common blood count findings. The association between periodontitis and WBC could be causal in nature. Further assessment to determine whether periodontitis causes changes in circulating blood cells and to identify the molecular mechanisms underlying these associations is warranted.