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Biomedical subjects

Manuel Mayr

Publications and source records attributed to Manuel Mayr.

At least 19 recordsLinked to original sources
PubMed2026

Generation of Fibrin-Based Three-Dimensional Engineered Vascular Tissues from Human Aortic Smooth Muscle Cells for Proteomic Analysis.

Vascular smooth muscle cells (SMCs) reside within the medial layer of blood vessels, where they interact with an extracellular matrix (ECM) composed of collagen, elastin, and proteoglycans to maintain vascular structure and function. Aberrant ECM remodeling contributes to multiple vascular diseases; however, conventional two-dimensional culture systems do not adequately recapitulate the three-dimensional (3D) cellular and matrix environment required to study SMC-ECM interactions and matrix remodeling. This protocol describes the generation of engineered vascular tissues (EVTs) from primary human aortic SMCs cultured within fibrin-based 3D hydrogels. Following casting between flexible polydimethylsiloxane posts, EVTs undergo cellular alignment, contraction, and deposit de novo ECM, providing a physiologically relevant platform for studying vascular matrix biology. The protocol details tissue fabrication, culture, harvesting, and downstream analysis of newly deposited ECM by immunofluorescence staining. In addition, a workflow is presented for qualitative and quantitative characterization of EVT-derived proteins using Western blotting and mass spectrometry-based proteomics. Sequential protein extraction enables assessment of soluble and ECM-enriched protein fractions, facilitating in-depth evaluation of ECM composition. This platform provides a reproducible approach for investigating ECM production and remodeling by human SMCs in a 3D environment.

Humans↗
PubMed2026

Editor's Choice - Aquaporin-4: A Predictor and Therapeutic Target for Permanent Paraplegia after Endovascular Thoraco-abdominal Aortic Aneurysm Repair.

OBJECTIVE: Endovascular thoraco-abdominal aortic aneurysm (TAAA) repair can impair spinal cord perfusion, leading to paraplegia. The mechanisms driving this devastating complication are poorly understood. This study aimed to interrogate the cerebrospinal fluid (CSF) proteome in patients after TAAA repair to identify biomarkers that herald permanent paraplegia. It also aimed to investigate a potential therapeutic target identified by proteomics using an in vivo model of ischaemic spinal cord injury (iSCI). METHODS: CSF was collected for proteomic analysis from patients before and following TAAA repair. A differentially expressed protein identified in human paraplegic subjects was subsequently interrogated in a rodent model of iSCI. The protein composition of CSF was analysed using tandem mass tag proteomics. Neurological examinations were carried out by a blinded neurologist and T2 weighted magnetic resonance imaging (MRI) was used to measure spinal cord volume and oedema. A rodent model of iSCI was used to investigate a clinically relevant therapeutic target informed by proteomic findings. RESULTS: CSF analysis was taken from 37 patients, all of whom had aneurysm repair using a custom branched and or fenestrated device (median age 73.5 years, range 67 - 78 years; 27 men, ten women; Crawford classification: six type I, 11 type II, 15 type III, three type IV, and two type V). Five patients remained permanently paraplegic and seven recovered from transient paraplegia. The CSF of patients who remained paraplegic contained approximately fourfold more aquaporin-4 (AQP4) (41.8 &#xb1; 19.2 ng/mL, n = 5) than those who recovered from paraplegia (10.8 &#xb1; 1.3 ng/mL, n = 7; p = .005) or did not develop paraplegia (10.8 &#xb1; 1.2 ng/mL, n = 25; p = .004). Permanently paraplegic patients had CSF AQP4 levels > 15 ng/mL and this was associated with greater cord oedema on T2 weighted MRI (1.77 &#xb1; 0.19 vs. 1.03 &#xb1; 0.36; p = .032). In a rodent model of iSCI, AQP4 inhibition preserved spinal neurons and glia in the dorsal horn and intermediate zones of white matter (p = .004) and protected against ischaemia induced paraplegia (p < .001). CONCLUSION: The AQP4 level in the CSF of a patient represents a prognostic marker of permanent paraplegia after TAAA repair and highlights a novel therapeutic target. These findings represent a conceptual advance in the management of iSCI.

Paraplegia↗
PubMed2006

The role of oxidant stress in angiotensin II-mediated contraction of human resistance arteries in the state of health and the presence of cardiovascular disease.

BACKGROUND: Angiotensin II is a powerful vasoconstrictor and regulator of cardiovascular growth. Also, it increases formation of reactive oxygen species and contributes to vascular dysfunction. We investigated the role of oxidant stress in contraction of human resistance arteries to angiotensin II, in health and in the presence of cardiovascular disease. METHODS AND PATIENTS: Studies of isometric contraction to angiotensin II, using human resistance arteries from healthy volunteers and patients, undergoing cardiac revascularization surgery, were performed by the broad-spectrum antioxidant agent vitamin C and superoxide dismutase mimetic TEMPOL. In the presence of vitamin C, the potency and the maximum contractile response were reduced in both patients and healthy volunteers. Addition of TEMPOL caused a decrease in angiotensin II-induced contraction only in the patients' group. CONCLUSIONS: Our studies provide evidence for the role of oxidant stress in the contractile response of human resistance arteries to angiotensin II. In patients with cardiovascular disease, the superoxide anion may be the major species involved. In healthy subjects, other reactive oxygen species and the redox-independent vasoconstrictor action of angiotensin II predominate. CONDENSED ABSTRACT: Increased formation of reactive oxygen species, due to angiotensin II, contributes to vascular dysfunction. We determined the oxidative reactivity of human resistance arteries to angiotensin II in healthy subjects and patients, undergoing cardiac revascularization surgery, using the broad-spectrum antioxidant agent, vitamin C, and superoxide dismutase mimetic, TEMPOL. There was a large decrease in potency and maximum of angiotensin II-induced contractile response noted in both groups with the former, while the latter reduced contraction only in the patients' group. Superoxide anion may play a major role in angiotensin II contractions of human resistance arteries in the presence of cardiovascular disease. In healthy subjects, other reactive species and the redox-independent pathways predominate.

Aged↗
PubMed2006

Oxidized low-density lipoprotein autoantibodies, chronic infections, and carotid atherosclerosis in a population-based study.

OBJECTIVES: We investigated whether associations exist between immune reactions to oxidized low-density lipoproteins (OxLDLs), chronic infections, and carotid atherosclerosis as quantified by ultrasound. BACKGROUND: Atherosclerosis is a chronic immuno-inflammatory disease wherein both oxidized lipids and infectious agents are incriminated as possible contributors. METHODS: We measured immunoglobulin (Ig)G and IgM autoantibody titers to copper-oxidized-LDL and malondialdehyde-LDL (OxLDL-AB), IgG and IgM apolipoprotein B-100-immune complexes (ApoB-IC), and titers of antibodies to Escherichia coli and chlamydial lipopolysaccharide (LPS), mycobacterial heat shock protein 65 (mHSP65), Chlamydia pneumoniae, Helicobacter pylori, and cytomegalovirus and evaluated their relationship to cardiovascular risk factors, chronic infections, and incident/progressive carotid atherosclerosis in the Bruneck study. RESULTS: The OxLDL-AB and ApoB-IC levels remained stable over time as indicated by strong correlations between 1995 and 2000 measurements (p < 0.001 each). Significant associations existed between all OxLDL markers and antibody titers to pathogens, especially to E. coli-LPS and mHSP65. Both OxLDL-AB and ApoB-IC levels showed a rise with increasing pathogen burden. Notably, OxLDL-ABs were also elevated in subjects with chronic infection as defined by clinical criteria. Titers of IgG, but not IgM, OxLDL-AB, or ApoB-IC inversely correlated with total cholesterol, LDL cholesterol, and apoB concentrations. The IgG OxLDL markers were positively and IgM markers were inversely associated with incident and progressive carotid atherosclerosis in univariate analyses but were not independent predictors in multivariate analyses. CONCLUSIONS: Our study provides evidence for an association between human oxLDL markers and chronic infections. Moreover, in this population-based study, neither IgG nor IgM OxLDL autoantibodies were independently predictive of atherosclerosis progression in the carotid arteries.

Adult↗
PubMed2006

Oxidized phospholipids predict the presence and progression of carotid and femoral atherosclerosis and symptomatic cardiovascular disease: five-year prospective results from the Bruneck study.

OBJECTIVES: The purpose of this work was to determine the predictive value of oxidized phospholipids (OxPLs) present on apolipoprotein B-100 particles (apoB) in carotid and femoral atherosclerosis. BACKGROUND: The OxPLs are pro-inflammatory and pro-atherogenic and may be detected using the antibody E06 (OxPL/apoB). METHODS: The Bruneck study is a prospective population-based survey of 40- to 79-year-old men and women initiated in 1990. Plasma levels of OxPL/apoB and lipoprotein (a) [Lp(a)] were measured in 765 of 826 (92.6%) and 671 of 684 (98.1%) subjects alive in 1995 and 2000, respectively, and correlated with ultrasound measures of carotid and femoral atherosclerosis. RESULTS: The distribution of the OxPL/apoB levels was skewed to lower levels and nearly identical to Lp(a) levels. The OxPL/apoB and Lp(a) levels were highly correlated (r = 0.87, p < 0.001), and displayed long-term stability and lacked correlations with most cardiovascular risk factors and lifestyle variables. The number of apolipoprotein (a) kringle IV-2 repeats was inversely related to Lp(a) mass (r = -0.48, p < 0.001) and OxPL/apoB levels (r = -0.46, p < 0.001). In multivariable analysis, OxPL/apoB levels were strongly and significantly associated with the presence, extent, and development (1995 to 2000) of carotid and femoral atherosclerosis and predicted the presence of symptomatic cardiovascular disease. Both OxPL/apoB and Lp(a) levels showed similar associations with atherosclerosis severity and progression, suggesting a common biological influence on atherogenesis. CONCLUSIONS: This study suggests that pro-inflammatory oxidized phospholipids, present primarily on Lp(a), are significant predictors of the presence and extent of carotid and femoral atherosclerosis, development of new lesions, and increased risk of cardiovascular events. The OxPL biomarkers may provide valuable insights into diagnosing and monitoring cardiovascular disease.

Aged↗
PubMed2006

Proteomic analysis reveals higher demand for antioxidant protection in embryonic stem cell-derived smooth muscle cells.

Embryonic stem (ES) cells can differentiate into vascular smooth muscle cells (SMCs), but differences in protein composition, function and behaviour between stem cell-derived and mature SMCs remain to be characterized. Using differential in gel electrophoresis (DIGE) and MS, we identified 146 proteins that differed between ES cell-derived SMCs (esSMCs) and aortic SMCs, including proteins involved in DNA maintenance (higher in esSMCs), cytoskeletal proteins and calcium-binding proteins (higher in aortic SMCs). Notably, esSMCs showed decreased expression of mitochondrial, but a compensatory increase of cytosolic antioxidants. Subsequent experiments revealed that mitochondrial-derived reactive oxygen species (ROS) were markedly increased in esSMCs. Despite a three-fold rise in glutathione (GSH) reductase activity, esSMCs had lower levels of reduced GSH, and depletion of GSH by diethyl maleate or inhibition of GSH reductase by carmustine (BCNU) resulted in more pronounced cell death compared to aortic SMCs, while addition of antioxidants improved the viability of esSMCs. We present the first proteomic analysis of esSMCs demonstrating that stem cell-derived SMCs are more sensitive to oxidative stress due to increased generation of mitochondrial-derived ROS and require additional antioxidant protection for survival.

Animals↗
PubMed2005

Association of serum-soluble heat shock protein 60 with carotid atherosclerosis: clinical significance determined in a follow-up study.

BACKGROUND AND PURPOSE: Previous work has shown that soluble heat shock protein 60 (HSP60; sHSP60), present in circulating blood, is associated with carotid atherosclerosis. In the current evaluation, we tested the hypothesis that sHSP60 levels are associated with the progression of carotid arteriosclerosis, prospectively. METHODS: The association of sHSP60 with early atherogenesis (5-year development and progression of nonstenotic carotid plaques) was investigated as part of the population-based prospective Bruneck Study. The current study focused on the follow-up period between 1995 and 2000 and, thus, included 684 subjects. RESULTS: sHSP60 levels measured in 1995 and 2000 were highly correlated (r=0.40; P<0.001), indicating consistency over a 5-year period. Circulating HSP60 levels were significantly correlated with antilipopolysaccharide and anti-HSP60 antibodies. It was also elevated in subjects with chronic infection (top quintile group of HSP60, among subjects with and without chronic infection: 23.8% versus 17.0%; P=0.003 after adjustment for age and sex). HSP60 levels were significantly associated with early atherogenesis, both in the entire population (multivariate odds ratio, for a comparison between quintile group V versus I+II: 2.0 [1.2 to 3.5] and the subgroup free of atherosclerosis at the 1995 baseline: 3.8 [1.6 to 8.9]). The risk of early atherogenesis was additionally amplified when high-sHSP60 and chronic infection were present together. CONCLUSIONS: Our study provides the first prospective data confirming an association between high levels of sHSP60 and early carotid atherosclerosis. This possibly indicates an involvement of sHSP60 in activating proinflammatory processes associated with early vessel pathology.

Autoantigens↗
PubMed2005

Role of oxidative stress in angiotensin-II mediated contraction of human conduit arteries in patients with cardiovascular disease.

BACKGROUND: Angiotensin II is a powerful vasoconstrictor involved in the development of high blood pressure and in the regulation of cardiovascular growth. Recent reports have suggested that in addition to the classical pathways involved in transducing responses to receptor activation, formation of reactive oxygen species by angiotensin II may also be involved. We investigated the importance of oxidative stress in angiotensin II induced contraction in human conduit arteries from patients with cardiovascular disease. METHODS AND RESULTS: Isometric contraction studies using human radial arteries entailed probes modulating the redox-dependent reactions to define the oxidative pathways involved in angiotensin II contraction. In situ oxidative fluorescence was employed to detect immediate superoxide tissue production in radial and internal mammary arteries. Treatment with TEMPOL, human superoxide dismutase, diphenyleneiodonium, oxypurinol, NG-monomethyl L-arginine considerably decreased contractile response to angiotensin II in radial arteries. Similarly, angiotensin II-stimulated arterial superoxide production was reduced in the presence of the above inhibitors. On the contrary, used as controls, norepinephrine vasoconstriction was not associated with increase of superoxide and neither ciprofloxacin nor aminophylline altered basal or angiotensin II induced superoxide generation. CONCLUSIONS: Our findings provide evidence for the role of oxidative pathways in contractile response of human conduit arteries to angiotensin II. Angiotensin II induced superoxide anion production may be mediated by multiple inter-dependent rate-limiting enzymes in both types of artery. Our studies may have important implication for future therapeutic approaches involving inhibition of angiotensin II mediated superoxide generation in hypertension and prevention of cardiovascular disease. CONDENSED ABSTRACT: We studied the role of oxidant species in contraction responses to angiotensin II in human conduit arteries. Treating radial artery segments with the anti-oxidants with a range of inhibitors, affecting the redox dependent pathways, markedly reduced contraction to angiotensin II. In parallel experiments, oxidative fluorescence was assessed and compared in human radial and internal mammary artery. Angiotensin II induced superoxide anion production may be mediated by multiple inter-dependent rate-limiting enzymes in both types of artery.

Angiotensin II↗
PubMed2005

Proteomic and metabolomic analyses of atherosclerotic vessels from apolipoprotein E-deficient mice reveal alterations in inflammation, oxidative stress, and energy metabolism.

OBJECTIVE: Proteomics and metabolomics are emerging technologies to study molecular mechanisms of diseases. We applied these techniques to identify protein and metabolite changes in vessels of apolipoprotein E(-/-) mice on normal chow diet. METHODS AND RESULTS: Using 2-dimensional gel electrophoresis and mass spectrometry, we identified 79 protein species that were altered during various stages of atherogenesis. Immunoglobulin deposition, redox imbalance, and impaired energy metabolism preceded lesion formation in apolipoprotein E(-/-) mice. Oxidative stress in the vasculature was reflected by the oxidation status of 1-Cys peroxiredoxin and correlated to the extent of lesion formation in 12-month-old apolipoprotein E(-/-) mice. Nuclear magnetic resonance spectroscopy revealed a decline in alanine and a depletion of the adenosine nucleotide pool in vessels of 10-week-old apolipoprotein E(-/-) mice. Attenuation of lesion formation was associated with alterations of NADPH generating malic enzyme, which provides reducing equivalents for lipid synthesis and glutathione recycling, and successful replenishment of the vascular energy pool. CONCLUSIONS: Our study provides the most comprehensive dataset of protein and metabolite changes during atherogenesis published so far and highlights potential associations of immune-inflammatory responses, oxidative stress, and energy metabolism.

Animals↗
PubMed2005

Proteomic dataset of Sca-1+ progenitor cells.

Embryonic stem cells (ES cells) can differentiate into endothelial cells and smooth muscle cells (SMCs), which participate in vascular angiogenesis. In this study, we differentiated mouse ES cells into Sca-1(+) cells, which have the potential to serve as vascular progenitor cells, and mapped their proteome by 2-DE using a pH 3-10 non-linear gradient and 12% SDS-polyacrylamide gels. A subset of 300 protein spots was analysed and mapped, with 241 protein spots being identified by their PMF using MALDI-TOF MS or by partial amino acid sequencing using MS/MS. Our protein map is the first of Sca-1(+) progenitor cells and will facilitate the identification of proteins differentially expressed during stem cell differentiation. The proteome of adult arterial SMCs is described in an accompanying paper (in this issue, DOI 10.1002/pmic.200402045). All data are made accessible on our website http://www.vascular-proteomics.com.

Animals↗
PubMed2005

Proteomic dataset of mouse aortic smooth muscle cells.

In an accompanying study (in this issue, DOI 10.1002/pmic.200402044), we have characterised the proteome of Sca-1(+) progenitor cells, which may function as precursors of vascular smooth muscle cells (SMCs). In the present study, we have analysed and mapped protein expression in aortic SMCs of mice, using 2-DE, MALDI-TOF MS and MS/MS. The 2-D system comprised a non-linear immobilised pH 3-10 gradient in the first dimension (separating proteins with pI values of pH 3-10), and 12%T SDS-PAGE in the second dimension (separating proteins in the range 15,000-150,000 Da). Of the 2400 spots visualised, a subset of 267 protein spots was analysed, with 235 protein spots being identified corresponding to 154 unique proteins. The data presented here are the first map of aortic SMCs and the most extensive analysis of SMC proteins published so far. This valuable tool should provide a basis for comparative studies of protein expression in vascular smooth muscle of transgenic mice and is available on our website hhtp://www.vascular-proteomics.com.

Animals↗
PubMed2004

Proteomic and metabolomic analysis of vascular smooth muscle cells: role of PKCdelta.

Recent developments of proteomic and metabolomic techniques provide powerful tools for studying molecular mechanisms of cell function. Previously, we demonstrated that neointima formation was markedly increased in vein grafts of PKCdelta-deficient mice compared with wild-type controls. To clarify the underlying mechanism, we performed a proteomic and metabolomic analysis of cultured vascular smooth muscle cells (SMCs) derived from PKCdelta+/+ and PKCdelta-/- mice. Using 2-dimensional electrophoresis and mass spectrometry, we identified >30 protein species that were altered in PKCdelta-/- SMCs, including enzymes related to glucose and lipid metabolism, glutathione recycling, chaperones, and cytoskeletal proteins. Interestingly, nuclear magnetic resonance spectroscopy confirmed marked changes in glucose metabolism in PKCdelta-/- SMCs, which were associated with a significant increase in cellular glutathione levels resulting in resistance to cell death induced by oxidative stress. Furthermore, PKCdelta-/- SMCs overexpressed RhoGDIalpha, an endogenous inhibitor of Rho signaling pathways. Inhibition of Rho signaling was associated with a loss of stress fiber formation and decreased expression of SMC differentiation markers. Thus, we performed the first combined proteomic and metabolomic study in vascular SMCs and demonstrate that PKCdelta is crucial in regulating glucose and lipid metabolism, controlling the cellular redox state, and maintaining SMC differentiation.

Animals↗
PubMed2004

Vascular proteomics: linking proteomic and metabolomic changes.

Cardiovascular diseases constitute the largest of death in the Western world. Various stressors, including elevated blood pressure, smoking, diabetes, and hypercholesterolemia directly or indirectly damage the vessel wall, eventually inducing arterial stiffness (arteriosclerosis) and lipid accumulation (atherosclerosis). However, the molecular mechanisms of atheroma formation are not yet fully clarified. While many investigators have used proteomic techniques to study cardiac diseases, vascular proteomics is still in its infancy. The present review highlights studies, in which proteomics has been successfully applied to study protein alterations in the vasculature. Furthermore, we will summarize our recent progress in combining proteomic and metabolomic techniques to reveal protein and metabolite alterations in the cardiovascular system: two-dimensional (2-D) gel electrophoresis proved to be highly complementary to nuclear magnetic resonance (NMR) spectroscopy, in that post-translational modifications of the most abundant enzymes were displayed on 2-D gels while NMR spectroscopy revealed changes in the corresponding metabolites. Importantly, the simultaneous assessment of protein and metabolite changes translated purely descriptive proteomic and metabolomic profiles into a functional context and provided important insights into pathophysiological mechanisms that would not have been obtained by other techniques.

Animals↗
PubMed2004

Loss of PKC-delta alters cardiac metabolism.

PKC-delta is believed to play an essential role in cardiomyocyte growth. In the present study, we investigated the effect of PKC-delta on cardiac metabolism using PKC-delta knockout mice generated in our laboratories. Proteomic analysis of heart protein extracts revealed profound changes in enzymes related to energy metabolism: certain isoforms of glycolytic enzymes, e.g., lactate dehydrogenase and pyruvate kinase, were absent or decreased, whereas several enzymes involved in lipid metabolism, e.g., phosphorylated isoforms of acyl-CoA dehydrogenases, showed a marked increase in PKC-delta(-/-) hearts. Moreover, PKC-delta deficiency was associated with changes in antioxidants, namely, 1-Cys peroxiredoxin and selenium-binding protein 1, and posttranslational modifications of chaperones involved in cytoskeleton regulation, such as heat shock protein (HSP)20, HSP27, and the zeta-subunit of the cytosolic chaperone containing the T-complex polypeptide 1. High-resolution NMR analysis of cardiac metabolites confirmed a significant decrease in the ratio of glycolytic end products (alanine + lactate) to end products of lipid metabolism (acetate) in PKC-delta(-/-) hearts. Taken together, our data demonstrate that loss of PKC-delta causes a shift from glucose to lipid metabolism in murine hearts, and we provide a detailed description of the enzymatic changes on a proteomic level. The consequences of these metabolic alterations on sensitivity to myocardial ischemia are further explored in the accompanyingpaper (20).

Animals↗
PubMed2004

Ischemic preconditioning exaggerates cardiac damage in PKC-delta null mice.

Ischemic preconditioning confers cardiac protection during subsequent ischemia-reperfusion, in which protein kinase C (PKC) is believed to play an essential role, but controversial data exist concerning the PKC-delta isoform. In an accompanying study (26), we described metabolic changes in PKC-delta knockout mice. We now wanted to explore their effect on early preconditioning. Both PKC-delta(-/-) and PKC-delta(+/+) mice underwent three cycles of 5-min left descending artery occlusion/5-min reperfusion, followed by 30-min occlusion and 2-h reperfusion. Unexpectedly, preconditioning exaggerated ischemia-reperfusion injury in PKC-delta(-/-) mice. Whereas ischemic preconditioning increased superoxide anion production in PKC-delta(+/+) hearts, no increase in reactive oxygen species was observed in PKC-delta(-/-) hearts. Proteomic analysis of preconditioned PKC-delta(+/+) hearts revealed profound changes in enzymes related to energy metabolism, e.g., NADH dehydrogenase and ATP synthase, with partial fragmentation of these mitochondrial enzymes and of the E(2) component of the pyruvate dehydrogenase complex. Interestingly, fragmentation of mitochondrial enzymes was not observed in PKC-delta(-/-) hearts. High-resolution NMR analysis of cardiac metabolites demonstrated a similar rise of phosphocreatine in PKC-delta(+/+) and PKC-delta(-/-) hearts, but the preconditioning-induced increase in phosphocholine, alanine, carnitine, and glycine was restricted to PKC-delta(+/+) hearts, whereas lactate concentrations were higher in PKC-delta(-/-) hearts. Taken together, our results suggest that reactive oxygen species generated during ischemic preconditioning might alter mitochondrial metabolism by oxidizing key mitochondrial enzymes and that metabolic adaptation to preconditioning is impaired in PKC-delta(-/-) hearts.

Acetyltransferases↗
PubMed2003

Cross-reactive B-cell epitopes of microbial and human heat shock protein 60/65 in atherosclerosis.

OBJECTIVE: Growing evidence suggests that immune reactions to heat shock protein 60 (HSP60) are involved in atherogenesis. Because of the high phylogenetic conservation between microbial and human HSP60, bacterial infections might be responsible for breaking the tolerance to self-HSP60, which is expressed on the surface of stressed arterial endothelial cells. METHODS AND RESULTS: We purified serum antibodies to Escherichia coli HSP60 (GroEL), the 60-kD chlamydial HSP, and HSP65 of Mycobacterium tuberculosis by affinity chromatography from clinically healthy subjects with sonographically proven carotid atherosclerosis. Reactivity of the purified antibodies with overlapping human HSP60 peptides was measured, and 8 shared common epitopes, recognized by all anti-bacterial HSP60/65 antibodies, were identified. Antisera specific for these cross-reactive epitopes were produced by immunizing rabbits with peptides derived from human HSP60. By immunohistochemistry, the epitopes were found to be present in the arterial wall of young subjects during the earliest stages of the disease. CONCLUSIONS: Antibodies to microbial HSP60/65 recognize specific epitopes on human HSP60. These cross-reactive epitopes were shown to serve as autoimmune targets in incipient atherosclerosis and might provide further insights into the mechanisms of early atherogenesis.

Amino Acid Sequence↗