Skip to main content
Advertisement
Browse Subject Areas
?

Click through the PLOS taxonomy to find articles in your field.

For more information about PLOS Subject Areas, click here.

  • Loading metrics

Plasma Clusterin and Lipid Profile: A Link with Aging and Cardiovascular Diseases in a Population with a Consistent Number of Centenarians

  • Angela Baralla,

    Affiliation Department of Biomedical Sciences, University of Sassari, Sassari, Italy

  • Elisabetta Sotgiu,

    Affiliation Department of Biomedical Sciences, University of Sassari, Sassari, Italy

  • Marta Deiana,

    Affiliations Associazione "L’Isola dei Centenari", Sassari, Italy, Department of Clinical and Experimental Medicine, Cardiology Unit, University of Sassari, Sassari, Italy

  • Sara Pasella,

    Affiliation Department of Biomedical Sciences, University of Sassari, Sassari, Italy

  • Sara Pinna,

    Affiliation Department of Biomedical Sciences, University of Sassari, Sassari, Italy

  • Andrea Mannu,

    Affiliation Department of Biomedical Sciences, University of Sassari, Sassari, Italy

  • Elisabetta Canu,

    Affiliation Department of Biomedical Sciences, University of Sassari, Sassari, Italy

  • Giovanni Sotgiu,

    Affiliation Department of Biomedical Sciences, University of Sassari, Sassari, Italy

  • Antonello Ganau,

    Affiliation Department of Clinical and Experimental Medicine, Cardiology Unit, University of Sassari, Sassari, Italy

  • Angelo Zinellu,

    Affiliation Department of Biomedical Sciences, University of Sassari, Sassari, Italy

  • Salvatore Sotgia,

    Affiliation Department of Biomedical Sciences, University of Sassari, Sassari, Italy

  • Ciriaco Carru,

    Affiliation Department of Biomedical Sciences, University of Sassari, Sassari, Italy

  • Luca Deiana

    proflucadeiana@gmail.com

    Affiliations Department of Biomedical Sciences, University of Sassari, Sassari, Italy, Associazione "L’Isola dei Centenari", Sassari, Italy

Abstract

The role of Clusterin in attenuation of inflammation and reverse cholesterol transfer makes this molecule a potential candidate as a marker for cancer, cardiovascular disease, diabetes mellitus, and metabolic syndrome. In elderly subjects cardiovascular diseases represent the primary cause of death and different clinical studies have shown a positive correlation of these diseases with changes in the lipid pattern. This work aimed at evaluating the relationship between circulating clusterin and the biochemical parameters that characterize the lipid profile of a Sardinian population divided into five age groups including centenarians; the high frequency in Sardinia of these long-lived individuals gave us the opportunity to extend the range of the age groups to be analyzed to older ages and to better evaluate the changes in the lipid balance during ageing and its relationship with clusterin concentration in plasma. Our results showed that Clusterin concentration values of the youngest group were more similar with the centenarian’s group compared to the other age groups, and a positive correlation arises with LDL. Furthermore given the high prevalence of cardiovascular diseases in the population examined and the association of Clusterin with these pathologies we evaluated Clusterin concentration variation in two groups with or without cardiovascular diseases. In presence of cardiovascular disease, Clusterin is significantly related to the most atherogenic components of lipid profile (total cholesterol and LDL), especially in women, suggesting its potential role in modulating cardiovascular metabolic risk factors.

Introduction

Clusterin (CLU)/Apo J is a glycoprotein of 70–80 kDa, it is a disulfide linked heterodimer composed of α and β subunits generated by a single cleavage from the protein precursor. It was originally identified in ram rete testis fluid, and later on it was found to be expressed in several tissues and in all human fluids [1]. It is present in plasma as a soluble protein or as a component of a lipid-poor subclass of high-density lipoproteins (HDLs) of molecular mass of 70–200 kDa [2,3]. Recent proteomic analyses revealed that CLU is also bound to LDL and very LDLs [46]even if the role in these lipoproteins is unknown. Clusterin has been reported to be implicated in several physiological processes such as sperm maturation, lipid transportation, complement inhibition, tissue remodeling, membrane recycling, cell-cell and cell-substratum interaction, stabilization of stressed proteins in a folding-competent state and promotion or inhibition of apoptosis. CLU is ubiquitously expressed in most cells and tissues, and is upregulated under a variety of pathological conditions including ageing, diabetes, atherosclerosis, degenerative diseases [79], moreover it has recently drawn much attention because of its association with cancer promotion and metastasis [1012]. CLU can exist within the cell to function in either proapoptotic or prosurvival processes. This diverse set of functions can be attributed to the existence of two alternatively spliced forms of the Clu gene that encode secretory CLU (sCLU) or nuclear CLU (nCLU). The sCLU form seems to be cytoprotective [13] while nCLU migrates to the nucleus on cytotoxic stress to trigger cell death [14,15]. Although its exact function has not been clearly defined, there is increasing evidence that CLU is induced by stress and functions as a cytoprotective extracellular chaperone similar to small heat shock proteins [1618]. During in vivo ageing Clu gene expression was found to increase from gestation to adults in humans [19], in the human pituitary gland [20], in the rat ventral prostate [21], in human glial cultures [22] and in human lymphocytes [23]. In serum sCLU levels seems to increase during in vivo ageing at least in males [8]. During vascular damage sCLU was found to accumulate in the human serum of diabetes type II patients or during myocardial infarction [8]; sCLU accumulates in the artery wall during atherosclerosis [24] and is present in human and mouse atherosclerotic lesions, but not in normal arterial tissue [25,26]. In tissue cultures it acts as an acceptor of cholesterol from macrophage-derived foam cells suggesting that CLU, present at high concentrations around stressed cells, has the potential to remove cholesterol from damaged cell membranes and then deliver it to HDL particles for subsequent disposal through reverse cholesterol transport [27]. In another work ApoJ was find to co-localize with E-LDL in atherosclerotic lesions and may thus subserve protective functions through its capacity to inactivate C5b-9 complement complexes and by reducing the cytotoxic effects of modified LDL on cells that gain contact with the lipoprotein [28]. Recent experiments by Martinez-Bujidos et al., performed with CLU-depleted LDLs demonstrated that CLU plays an active protective role against LDL aggregation [29]. Moreover in a recent work fasting plasma clusterin levels were found to be positively correlated with BMI, a parameter of whole body adiposity in healthy adults [30]. The purpose of this study was to evaluate clusterin concentration in plasma samples of a Sardinian population divided into five age groups with a consistent number of centenarians, as well as the concentration of the biochemical parameters that characterize the lipid profile of an individual, including high-density lipoprotein (HDL), low-density lipoprotein (LDL), triglycerides and total cholesterol, in order to establish if any relationship can be found between circulating clusterin and those parameters. Furthermore, since almost half of the population analysed suffered from cardiovascular diseases, which are the most common diseases between elderly people, and considering that several studies hold that CLU is implicated in various cardiovascular diseases (e.g. atherosclerosis, coronary heart disease and myocardial infarction) [26,3134] the same correlation analyses mentioned above with lipid parameters have been evaluated for CLU dividing the population by people with or without cardiovascular diseases.

Materials and Methods

Study Population

Subjects for this study were recruited through the AKeA project that studies the Sardinian centenarians [35,36]. The AKeA project has been approved by the Bioethic Committee of the University of Sassari and ASL N°1 Sassari. The major criteria for the selection of the partecipants were the chronological age, the residence in Sardinia (the majority of them being people coming from the same villages of centenarians) and the apparently healthy status. An informed written consent, approved by the above mentioned Bioethic Committee, was obtained from each subject or from a legally responsible family member. A standardized questionnaire on general information was also administered concerning gender, age, smoking habits, alcohol drinking, medications and health status (Table 1). Smoking was defined as smoking at least one cigarette a day and lasting more than six months. Alcohol drinking was defined as drinking any type of alcoholic beverage at least once a week and lasting more than six months. Smoking and drinking were classified as current (yes) previous (ex smoker/drinker) or never (no smoker/drinker). Hypertension was defined according to repeated blood pressure measurements ≥ 140/90 mmHg or previous diagnosis of hypertension and antihypertensive treatment. Almost half of the population (47.2%) had cardiovascular diseases which is the most common disease between elderly people (cardiovascular diseases were grouped as arterial hypertension (41.5%), angina (4.5%), heart failure (4.1%), myocardial infarction (1.2%), other cardiac diseases (1.6%; valvular diseases or cardiomyopathies)) while a minority of them suffered from chronic conditions (5.3%, epatic 15.8%, respiratory 11.4%, nervous systems 7.3%, tumors 8.5%, endocrine metabolic disorders 25.6%, cerebrovascular diseases 7.7%). Table A in S1 File shows the same data stratified by age groups. The population with 264 subjects was divided into 5 age groups (20–50 years (y): N = 53, 60–75y N = 49, 80–89y N = 48, 90–99y N = 46, ≥100y N = 68) for the age related analysis, while to examine the relationship with cardiovascular diseases the population was divided into two groups with or without cardiovascular diseases (N = 116, N = 148, respectively).

thumbnail
Table 1. Medications, smoking and drinking habits of the population analysed.

https://doi.org/10.1371/journal.pone.0128029.t001

Biochemical Parameters

Blood samples were collected in EDTA-coated tubes for clusterin analyses, and processed within two hour. The red cell fraction was then separated by centrifugation at 2500g at 4°C for 15 min and the clear plasma supernatant was stored in aliquots frozen at -80°C. For cholesterol, LDL, triglycerides and HDL blood was collected into gel vacutainer tubes and their concentration were assessed through enzymatic method using the ARCHITECT cSystems. Creatinine, Glucose and Urea with the ARCHITECT c8000 using enzymatic methods. For clusterin concentration in plasma a competitive ELISA kit (AdipoGen, Korea) was used following manufacturer instructions. All the statistical analyses were performed using SPSS v21 and MedCalc v12.7 softwares. The differences between groups were assessed through the Kruskal Wallis test followed by pairwise comparison Dunn’s test; for the correlation analyses the Spearman test was used. A p-value< 0.05 was considered statistically significant.

Results

In this paper we wanted to evaluate if Clusterin concentration changes during ageing and if a relationship exists with changes in the biochemical parameters characterizing the lipid profile of an individual such as high-density lipoprotein (HDL), low-density lipoprotein (LDL), triglycerides and total cholesterol. Table 2 shows the values of the parameters mentioned above in the population analyzed divided by age groups as previously described and the significant differences highlighted by Kruskal Wallis test. This analysis revealed a significant change in concentration for all of the parameters analyzed. Cholesterol, LDL and Triglycerides had an higher value in the group of 80–89years while in the older groups their level was lower (Table 2, Fig 1). HDL had the highest value in the group of 20–50 years with lower values in the other four groups. Clusterin had higher values in the group of 90–99 years while the group of centenarians had CLU values lower compared to the other elderly groups (Table 2, Fig 2), the pairwise comparisons test in the Supplementary data shows the p-values relative to the comparisons by pair groups (Table B in S1 File) highlighting how the youngest group has clusterin values statistically more similar to the centenarian’s group. No significative differences emerged between the five age groups for the other biochemical parameters evaluated (glucose, urea and creatitìnine) (Table 2). Considering the whole population the correlation analyses with the Spearman’s test showed that clusterin is positively correlated with LDL cholesterol (ρ = 0.196 p = 0.002) (Table 3) and the evaluation of gender differences revealed statistically significant correlations only in the females group, in particular a positive correlation between CLU and LDL (ρ = 0.29, p = 0.001) and a negative correlation between CLU and HDL (ρ = -0.183, p = 0.031) (Table 3). Dividing the population in the five age groups the correlation between CLU and LDL is concentrated only inside the group of 90–99 years old (ρ = 0.403, p = 0.006) (Table 4). Since the population analyzed had an high number of individuals with cardiovascular diseases and considering the association of Clusterin with different pathologies related to cardiovascular diseases we wanted to see if any difference existed between the two groups in the concentration values of both clusterin and lipid parameters. Table 5 shows how only triglycerides values were significantly different. For concentration values divided by age with or without cardiovascular diseases and relative p-values for comparisons see Table C in S1 File. The correlation analyses showed a stronger correlation with LDL (ρ = 0.30 p = 0.002) and other two correlations emerged, with total cholesterol and with triglycerides (ρ = 0.258 p = 0.007, ρ = 0.234 p = 0.014) but only inside the group of people that had cardiovascular diseases, while no significant correlation came out inside the healthier group (Table 5). When considering gender differences only females with cardiovascular diseases showed a positive correlation between CLU and LDL (ρ = 0.432 p = 0.001) and with total cholesterol (ρ = 0.406 p = 0.001) (Table 6).

thumbnail
Fig 1. Lipid parameters’ values in the five age groups.

Boxplots represent the Lipid parameters analysed in the five age groups, total cholesterol, LDL (low density lipoprotein), HDL (high density lipoprotein) and Triglycerides. Circles represent outliers and asterix extreme outliers.

https://doi.org/10.1371/journal.pone.0128029.g001

thumbnail
Fig 2. Clusterin concentration values in the five age groups.

Boxplots represent the Clusterin concentration values in the five age groups. Circles represent outliers.

https://doi.org/10.1371/journal.pone.0128029.g002

thumbnail
Table 2. Clusterin and biochemical parameter’s concentrations by Age group and Kruskal Wallis test for comparisons between the five age groups.

https://doi.org/10.1371/journal.pone.0128029.t002

thumbnail
Table 3. Correlations between Clusterin and Lipid parameters in the whole population and divided by gender.

https://doi.org/10.1371/journal.pone.0128029.t003

thumbnail
Table 4. Correlation between Clusterin and Lipid parameters divided by Age groups.

https://doi.org/10.1371/journal.pone.0128029.t004

thumbnail
Table 5. Clusterin and lipid parameters concentrations by presence or absence of cardiovascular diseases and Kruskal Wallis test for comparisons between the two groups.

https://doi.org/10.1371/journal.pone.0128029.t005

thumbnail
Table 6. Correlation between Clusterin and Lipid parameters in the two groups with or without cardiovascular diseases and divided by gender.

https://doi.org/10.1371/journal.pone.0128029.t006

Discussion

The role of clusterin in attenuation of inflammation and reverse cholesterol transfer makes this molecule a potential candidate as a marker for cancer, cardiovascular diseases, diabetes mellitus, and metabolic syndrome. In elderly subjects cardiovascular diseases represent the primary cause of death. Different epidemiological and clinical studies have shown that the incidence of atherosclerosis related vascular diseases is positively correlated with changes in the lipid pattern [37,38] highlighting the importance of cardiocirculatory conditions on human survival. The results obtained for Clusterin concentration in our population agreed in part with the data shown in literature by the work of Trougakos et al., where an increase of this protein during ageing occurs until 90 [8,31]. The novelty of this work is that our investigations spanned over older people showing an increase even after 90 years, but in centenarians, which have a life-long survival advantage [29,30], the clusterin values are lower compared to the other elderly groups. Until now, only one work has focused the attention on clusterin expression in centenarians [39], in particular Trougakos et al., found that clusterin gene expression level in lymphocyte samples of 25 centenarians was reduced as compared to elderly donors. Our work highlights for the first time the reduction of clusterin in plasma samples of centenarians at the protein level and fill the gap in the age range 90–99years. This behavior can be related, as already hypothesized by Trougakos et al.[39], to the clusterin function as a sensitive biosensor of environmental insults and particularly oxidative stress. Centenarians are considered as a model of successful ageing characterized by low ROS (reactive oxygen species) load [40], so, its reduction can be attributable to the lower ROS load of centenarians. Determination of oxidative stress biomarkers in plasma together with clusterin levels can be important to support this interesting hypothesis raised by Franceschi et al. Considering the two groups with or without cardiovascular diseases no statistically significant difference in clusterin concentration values were detectable. CLU involvement in reverse cholesterol transport and its potential protective role in atherogenesis through its binding to enzymatically modified low-density lipoprotein and its capacity to reduce fatty acid mediated cytotoxicity lead us to investigate the relationship of this protein with the lipid profile of the population analyzed. These analyses highlighted a positive correlation between Clusterin and LDL cholesterol. Dividing the population by gender the positive correlation appears only in the females group with an higher correlation value than the one detected for the whole population; furthermore, a negative association with HDL was found in this group. The association between CLU levels and LDL has been demonstrated for the first time by Aronis et al. in a population of young healthy individuals [41], but this group found a positive correlation even for total cholesterol. This work confirms the positive correlation found by Aronis et al. for LDL cholesterol extending the result to an higher age range. Moreover it highlighted gender differences revealing a stronger correlation for females between Clusterin and LDL-cholesterol. It has been reported that androgen, a member of sex hormone influences clusterin secretion [42], hence, hormone regulation can be a reason for the gender differences observed in the present work. Dividing the population in the five age groups the correlation between CLU and LDL is concentrated only inside the group of 90–99 years old. One reason for not having found a significant correlation in the other age groups can be related the small sample size. Ageing is a multifactorial process modulated by the interplay among genetic and environmental factors [43] and is associated with multiple, systemic dysfunctions of the body and accompanied by lipid metabolism disorders that in turn lead to more chronic medical conditions [44]. One of the leading cause of death in the elderly population are cardiovascular diseases and the association with dyslipidemia rises substantially with advancing age [45]. For this reason and considering the high number of people with cardiovascular diseases in our sample population, (see materials and methods for details on how they have been gathered) we made separate analyses for the presence or absence of cardiovascular diseases. The results of theses analyses showed a positive correlation between CLU and LDL only in the group with cardiovascular diseases and stronger than in the whole population. Moreover other lipid parameters besides LDL (total cholesterol and triglycerides) came out to be significantly correlated to CLU. In a recently published paper Martinez-Bujidos et al., provided evidence that CLU plays an active protective role against LDL aggregation and they proposed that the increased expression of CLU in atherosclerotic lesions could be a response of the arterial walls to LDL aggregation, the initial step of atherosclerosis [29]. These findings could be a possible explanation to the positive correlation obtained between CLU and LDL only inside the group with cardiovascular diseases if we consider that CLU changes can be the result of its action of counteracting the proatherogenic function of LDL through a prevention of their aggregation. The correlations highlighted by this work suggest a gender dependent lipid metabolism regulation in which clusterin protein may be involved and hence supports the hypothesis of its role in the disease mechanisms. Further investigations would be addressed to elucidate the molecular mechanisms involved in such regulation. During ageing usually an increase in total cholesterol levels occurs in both genders, while in advanced aging (octogenarians, nonagenarians), people show a lipid profile typical of low risk of atherosclerotic disease [46], with high HDL, low total cholesterol and low LDL and high HDL/total cholesterol ratio [47,48] compared with septuagenarians [48,49]. Epidemiological studies found that the plasma levels of HDL cholesterol decrease with increasing age, but in the elderly they are unchanged or slightly increased [50]. A paper by Baggio et al. reported that the mean HDL levels of centenarians (both males and females) are 20% lower than those of 65-year-old subjects [51]. The decreased levels of HDL can be due to inflammatory, hormonal and metabolic changes which are more prevalent with aging, while a possible explanation to the higher levels of HDL seen in some population in elderly people can be due to the decreased levels of androgens in aging men which result in an increase of HDL particles due to the reduced catabolism driven by testosterone [44]. In our sample population there is an evident change in the lipid profile with significant differences in the five age groups for all lipid parameters (Table 2). In our population an increase of total cholesterol and LDL cholesterol occurs from 20 to 89 years, while in nonagenarians and centenarians their level decreases but at values that are considered to be in the normal range (186.5mg/dL and 184mg/dL for nonagenarians and centenarians respectively) while different studies have reported that very low levels of total cholesterol are associated with an all-cause mortality [52,53]. The low values of total cholesterol and LDL can be important in reaching a lipid balance capable of preventing the occurrence of cardiovascular diseases. HDL levels, whose higher values are usually correlated with lower cardiovascular risk, were slightly lower if compared to the other groups. but at the same time the concentration values were above 40mg/dL which is desirable according to the ATP III guidelines [54]. In conclusion, the positive correlation found between Clusterin and the most atherogenic components of lipid profile (total cholesterol and LDL), highlights the importance that this protein can have in modulating the lipid balance of an individual especially during aging where visible changes in the lipid parameters occur, and in cardiovascular diseases where the absolute risk associated with dyslipidemia rises with advancing age [45].

Supporting Information

S1 File. Distribution of the diseases by age group in the population analyzed (Table A).

Paiwise comparisons between the five age groups (Table B). Clusterin and lipid parameters concentrations divided by presence or absence of Cardiovascular diseases and by age groups (Table C).

https://doi.org/10.1371/journal.pone.0128029.s001

(DOC)

Acknowledgments

We gratefully acknowledge the AKeA project equipe (P.I. Luca Deiana) and the Associazione "Isola dei Centenari".

Author Contributions

Conceived and designed the experiments: AB LD S. Pasella. Performed the experiments: AB ES S. Pinna EC AM LD. Analyzed the data: AB GS LD. Contributed reagents/materials/analysis tools: LD MD. Wrote the paper: AB LD AG. Technical support: SS AZ CC MD.

References

  1. 1. Bettuzzi S (2009) Conclusions and perspectives. Adv Cancer Res 105: 133–150. pmid:19879427
  2. 2. Blatter MC, James RW, Messmer S, Barja F, Pometta D (1993) Identification of a distinct human high-density lipoprotein subspecies defined by a lipoprotein-associated protein, K-45. Identity of K-45 with paraoxonase. Eur J Biochem 211: 871–879. pmid:8382160
  3. 3. Stuart WD, Krol B, Jenkins SH, Harmony JA (1992) Structure and stability of apolipoprotein J-containing high-density lipoproteins. Biochemistry 31: 8552–8559. pmid:1390641
  4. 4. Banfi C, Brioschi M, Barcella S, Wait R, Begum S, et al. (2009) Proteomic analysis of human low-density lipoprotein reveals the presence of prenylcysteine lyase, a hydrogen peroxide-generating enzyme. Proteomics 9: 1344–1352. pmid:19253276
  5. 5. Karlsson H, Leanderson P, Tagesson C, Lindahl M (2005) Lipoproteomics I: mapping of proteins in low-density lipoprotein using two-dimensional gel electrophoresis and mass spectrometry. Proteomics 5: 551–565. pmid:15627967
  6. 6. Sun HY, Chen SF, Lai MD, Chang TT, Chen TL, et al. (2010) Comparative proteomic profiling of plasma very-low-density and low-density lipoproteins. Clin Chim Acta 411: 336–344. pmid:19945452
  7. 7. Jones SE, Jomary C (2002) Clusterin. Int J Biochem Cell Biol 34: 427–431. pmid:11906815
  8. 8. Trougakos IP, Gonos ES (2002) Clusterin/apolipoprotein J in human aging and cancer. Int J Biochem Cell Biol 34: 1430–1448. pmid:12200037
  9. 9. Choi-Miura NH, Oda T (1996) Relationship between multifunctional protein "clusterin" and Alzheimer disease. Neurobiol Aging 17: 717–722. pmid:8892344
  10. 10. Pucci S, Bonanno E, Pichiorri F, Angeloni C, Spagnoli LG (2004) Modulation of different clusterin isoforms in human colon tumorigenesis. Oncogene 23: 2298–2304. pmid:14755245
  11. 11. Redondo M, Villar E, Torres-Munoz J, Tellez T, Morell M, et al. (2000) Overexpression of clusterin in human breast carcinoma. Am J Pathol 157: 393–399. pmid:10934144
  12. 12. Shannan B, Seifert M, Leskov K, Willis J, Boothman D, et al. (2006) Challenge and promise: roles for clusterin in pathogenesis, progression and therapy of cancer. Cell Death Differ 13: 12–19. pmid:16179938
  13. 13. Chi KN, Siu LL, Hirte H, Hotte SJ, Knox J, et al. (2008) A phase I study of OGX-011, a 2'-methoxyethyl phosphorothioate antisense to clusterin, in combination with docetaxel in patients with advanced cancer. Clin Cancer Res 14: 833–839. pmid:18245546
  14. 14. Caccamo AE, Scaltriti M, Caporali A, D'Arca D, Corti A, et al. (2005) Ca2+ depletion induces nuclear clusterin, a novel effector of apoptosis in immortalized human prostate cells. Cell Death Differ 12: 101–104. pmid:15499376
  15. 15. Leskov KS, Klokov DY, Li J, Kinsella TJ, Boothman DA (2003) Synthesis and functional analyses of nuclear clusterin, a cell death protein. J Biol Chem 278: 11590–11600. pmid:12551933
  16. 16. Zoubeidi A, Chi K, Gleave M (2010) Targeting the cytoprotective chaperone, clusterin, for treatment of advanced cancer. Clin Cancer Res 16: 1088–1093. pmid:20145158
  17. 17. Humphreys DT, Carver JA, Easterbrook-Smith SB, Wilson MR (1999) Clusterin has chaperone-like activity similar to that of small heat shock proteins. J Biol Chem 274: 6875–6881. pmid:10066740
  18. 18. Michel D, Chatelain G, North S, Brun G (1997) Stress-induced transcription of the clusterin/apoJ gene. Biochem J 328 (Pt 1): 45–50. pmid:9359832
  19. 19. Wong P, Taillefer D, Lakins J, Pineault J, Chader G, et al. (1994) Molecular characterization of human TRPM-2/clusterin, a gene associated with sperm maturation, apoptosis and neurodegeneration. Eur J Biochem 221: 917–925. pmid:8181474
  20. 20. Ishikawa T, Zhu BL, Li DR, Zhao D, Michiue T, et al. (2006) Age-dependent increase of clusterin in the human pituitary gland. Leg Med (Tokyo) 8: 28–33. pmid:16221554
  21. 21. Lau KM, Tam NN, Thompson C, Cheng RY, Leung YK, et al. (2003) Age-associated changes in histology and gene-expression profile in the rat ventral prostate. Lab Invest 83: 743–757. pmid:12746483
  22. 22. Patel NV, Wei M, Wong A, Finch CE, Morgan TE (2004) Progressive changes in regulation of apolipoproteins E and J in glial cultures during postnatal development and aging. Neurosci Lett 371: 199–204. pmid:15519757
  23. 23. Trougakos IP, Gonos ES (2006) Regulation of clusterin/apolipoprotein J, a functional homologue to the small heat shock proteins, by oxidative stress in ageing and age-related diseases. Free Radic Res 40: 1324–1334. pmid:17090421
  24. 24. Mackness B, Hunt R, Durrington PN, Mackness MI (1997) Increased immunolocalization of paraoxonase, clusterin, and apolipoprotein A-I in the human artery wall with the progression of atherosclerosis. Arterioscler Thromb Vasc Biol 17: 1233–1238. pmid:9261251
  25. 25. Ishikawa Y, Akasaka Y, Ishii T, Komiyama K, Masuda S, et al. (1998) Distribution and synthesis of apolipoprotein J in the atherosclerotic aorta. Arterioscler Thromb Vasc Biol 18: 665–672. pmid:9555874
  26. 26. Jordan-Starck TC, Lund SD, Witte DP, Aronow BJ, Ley CA, et al. (1994) Mouse apolipoprotein J: characterization of a gene implicated in atherosclerosis. J Lipid Res 35: 194–210. pmid:8169523
  27. 27. Gelissen IC, Hochgrebe T, Wilson MR, Easterbrook-Smith SB, Jessup W, et al. (1998) Apolipoprotein J (clusterin) induces cholesterol export from macrophage-foam cells: a potential anti-atherogenic function? Biochem J 331 (Pt 1): 231–237. pmid:9512484
  28. 28. Schwarz M, Spath L, Lux CA, Paprotka K, Torzewski M, et al. (2008) Potential protective role of apoprotein J (clusterin) in atherogenesis: binding to enzymatically modified low-density lipoprotein reduces fatty acid-mediated cytotoxicity. Thromb Haemost 100: 110–118. pmid:18612545
  29. 29. Martinez-Bujidos M, Rull A, Gonzalez-Cura B, Perez-Cuellar M, Montoliu-Gaya L, et al. (2014) Clusterin/apolipoprotein J binds to aggregated LDL in human plasma and plays a protective role against LDL aggregation. FASEB J.
  30. 30. Won JC, Park CY, Oh SW, Lee ES, Youn BS, et al. (2014) Plasma clusterin (ApoJ) levels are associated with adiposity and systemic inflammation. PLoS One 9: e103351. pmid:25076422
  31. 31. Trougakos IP, Poulakou M, Stathatos M, Chalikia A, Melidonis A, et al. (2002) Serum levels of the senescence biomarker clusterin/apolipoprotein J increase significantly in diabetes type II and during development of coronary heart disease or at myocardial infarction. Exp Gerontol 37: 1175–1187. pmid:12470829
  32. 32. Kujiraoka T, Hattori H, Miwa Y, Ishihara M, Ueno T, et al. (2006) Serum apolipoprotein j in health, coronary heart disease and type 2 diabetes mellitus. J Atheroscler Thromb 13: 314–322. pmid:17192696
  33. 33. Poulakou MV, Paraskevas KI, Vlachos IS, Karabina SA, Wilson MR, et al. (2008) Effect of statins on serum apolipoprotein j and paraoxonase-1 levels in patients with ischemic heart disease undergoing coronary angiography. Angiology 59: 137–144. pmid:18403458
  34. 34. Ishikawa Y, Ishii T, Akasaka Y, Masuda T, Strong JP, et al. (2001) Immunolocalization of apolipoproteins in aortic atherosclerosis in American youths and young adults: findings from the PDAY study. Atherosclerosis 158: 215–225. pmid:11500194
  35. 35. Deiana L, Ferrucci L, Pes GM, Carru C, Delitala G, et al. (1999) AKEntAnnos. The Sardinia Study of Extreme Longevity. Aging (Milano) 11: 142–149. pmid:10476308
  36. 36. Deiana L, Pes GM, Carru C, Ferrucci L, Franceschi C, et al. (2002) The "Oldest Man on the Planet". J Am Geriatr Soc 50: 2098–2099. pmid:12473030
  37. 37. Berns MA, de Vries JH, Katan MB (1988) Determinants of the increase of serum cholesterol with age: a longitudinal study. Int J Epidemiol 17: 789–796. pmid:3225086
  38. 38. Gillum RF, Taylor HL, Brozek J, Anderson J, Blackburn H (1982) Blood lipids in young men followed 32 years. J Chronic Dis 35: 635–641. pmid:7096527
  39. 39. Trougakos IP, Petropoulou C, Franceschi C, Gonos ES (2006) Reduced expression levels of the senescence biomarker clusterin/apolipoprotein j in lymphocytes from healthy centenarians. Ann N Y Acad Sci 1067: 294–300. pmid:16804001
  40. 40. Franceschi C, Bonafe M (2003) Centenarians as a model for healthy aging. Biochem Soc Trans 31: 457–461. pmid:12653662
  41. 41. Aronis KN, Vamvini MT, Chamberland JP, Mantzoros CS (2011) Circulating clusterin (apolipoprotein J) levels do not have any day/night variability and are positively associated with total and LDL cholesterol levels in young healthy individuals. J Clin Endocrinol Metab 96: E1871–1875. pmid:21900379
  42. 42. Miwa Y, Takiuchi S, Kamide K, Yoshii M, Horio T, et al. (2005) Insertion/deletion polymorphism in clusterin gene influences serum lipid levels and carotid intima-media thickness in hypertensive Japanese females. Biochem Biophys Res Commun 331: 1587–1593. pmid:15883054
  43. 43. Holliday R (1998) Causes of aging. Ann N Y Acad Sci 854: 61–71. pmid:9928420
  44. 44. Hui-Hui Liu J-JL (2014) Aging and dyslipidemia: A review of potential mechanisms. Aging Research Reviews 19: 43–52. pmid:25500366
  45. 45. Gobal FA, Mehta JL (2010) Management of dyslipidemia in the elderly population. Ther Adv Cardiovasc Dis 4: 375–383. pmid:20965950
  46. 46. Kolovou G, Kolovou V, Vasiliadis I, Wierzbicki AS, Mikhailidis DP (2011) Ideal lipid profile and genes for an extended life span. Curr Opin Cardiol 26: 348–355. pmid:21478743
  47. 47. Arai Y, Hirose N (2004) Aging and HDL metabolism in elderly people more than 100 years old. J Atheroscler Thromb 11: 246–252. pmid:15557706
  48. 48. Malaguarnera M, Giugno I, Ruello P, Rizzo M, Panebianco MP, et al. (1998) Lipid profile variations in a group of healthy elderly and centenarians. Eur Rev Med Pharmacol Sci 2: 75–79. pmid:10229562
  49. 49. Suzuki M, Wilcox BJ, Wilcox CD (2001) Implications from and for food cultures for cardiovascular disease: longevity. Asia Pac J Clin Nutr 10: 165–171. pmid:11710359
  50. 50. Walter M (2009) Interrelationships among HDL metabolism, aging, and atherosclerosis. Arterioscler Thromb Vasc Biol 29: 1244–1250. pmid:19667114
  51. 51. Baggio G, Donazzan S, Monti D, Mari D, Martini S, et al. (1998) Lipoprotein(a) and lipoprotein profile in healthy centenarians: a reappraisal of vascular risk factors. FASEB J 12: 433–437. pmid:9535215
  52. 52. Okamura T, Kadowaki T, Hayakawa T, Kita Y, Okayama A, et al. (2003) What cause of mortality can we predict by cholesterol screening in the Japanese general population? J Intern Med 253: 169–180. pmid:12542557
  53. 53. Nago N, Ishikawa S, Goto T, Kayaba K (2011) Low cholesterol is associated with mortality from stroke, heart disease, and cancer: the Jichi Medical School Cohort Study. J Epidemiol 21: 67–74. pmid:21160131
  54. 54. (2001) Executive Summary of The Third Report of The National Cholesterol Education Program (NCEP) Expert Panel on Detection, Evaluation, And Treatment of High Blood Cholesterol In Adults (Adult Treatment Panel III). 2486–2497 p.