Vascular risk factors affect cerebral blood flow (CBF) and cerebral vascular reactivity, contributing to cognitive decline. Hippocampus is vulnerable to both Alzheimer's disease (AD) pathology and ischemia; nonetheless, the information about the impact of vascular risk on hippocampal perfusion is minimal. Cognitively, healthy elderly (NL18, 69.96.7 years) and subjects with mild cognitive impairment (MCI15, 74.98.1 years) were evaluated for the Framingham cardiovascular risk profile (FCRP). All underwent structural imaging and resting CBF assessment with arterial spin labeling (ASL) at 3T magnetic resonance imaging (MRI). In 24 subjects (NL17, MCI7), CBF was measured after a carbon dioxide rebreathing challenge. Across all subjects, FCRP negatively correlated with hippocampal (0.41, P0.049) and global cortical (0.46, P0.02) vasoreactivity to hypercapnia (VRh). The FCRP-VRh relationships were most pronounced in the MCI group: hippocampus (0.77, P=0.04); global cortex (0.83, P=0.02). The FCRP did not correlate with either volume or resting CBF. The hippocampal VR h was lower in MCI than in NL subjects (Z2.0, P=0.047). This difference persisted after age and FCRP correction (F 3,20 4.6, P0.05). An elevated risk for vascular pathology is associated with a reduced response to hypercapnia in both hippocampal and cortical tissue. The VR h is more sensitive to vascular burden than either resting CBF or brain volume.

Background: Elevation of C-reactive protein (CRP) levels in blood was recognized as one of the cardiac disease risk factors. Consumption of wine is shown to reduce the risk from heart disease and improve longevity. Objectives: In the present study, we evaluated the effect of various wine polyphenolic compounds and several active synthetic derivatives of resveratrol on the inflammatory cytokines (IL-1β+IL-6)-induced CRP expression in Hep3B cells. Results: Among the wine phenolics tested, quercetin and resveratrol, in a dose-dependent manner, suppressed cytokine-induced CRP expression. Two of the synthetic derivatives of resveratrol, R3 and 7b, elicited a fiftyfold higher suppressive effect compared with resveratrol. The inhibitory effects of resveratrol and its derivatives on CRP expression were at the level of mRNA production. Investigation of signaling pathways showed that the cytokines induced the phosphorylation of p38 and p44/42 MAP kinases. Inhibitors of p38 and p44/42 mitogen-activated protein kinase (MAPK) activation inhibited CRP expression, implicating the involvement of both pathways in cytokine-induced CRP expression. These data revealed a previously unrecognized role of the p44/42 MAPK signaling pathway in CRP expression. Wine polyphenolics or the synthetic compounds of resveratrol did not affect cytokine-activated phosphorylation of these MAPKs. Conclusions: Wine phenolics inhibit CRP expression; however, to do so, they do not utilize the MAPK pathways.

C-reactive protein (CRP) is made in liver and its serum concentration increases in inflammation. Measurement of serum CRP is recommended for use as an indicator of inflammation and predictor of atherosclerosis. Cholesterol-lowering drugs statins also lower CRP. To evaluate statin-mediated CRP reduction and to reassess clinical usefulness of CRP, we investigated regulation of CRP gene expression. Here, we show that pravastatin and simvastatin prevent the induction of CRP expression in human hepatoma Hep3B cells exposed to proinflammatory cytokines IL-6 and IL-1β. The nitric oxide (NO) donor, sodium nitroprusside, also prevented the induction of CRP expression while the CRP inducers IL-6 and IL-1β were present with the cells. The effect of NO on CRP expression was at the level of transcription. These findings suggest that the decrease in CRP level in vivo after statin-treatment does not necessarily reflect absence of inflammation, and that NO-releasing drugs have the potential to reduce serum CRP levels. Thus, the measurement of serum CRP levels alone in individuals on statin/NO-therapy is not as useful as was imagined.

The relationship between hyperlipidemia and sensorineural hearing loss remains obscure. In this study, we elucidate for the first time the cochlear morphological and auditory alterations and their relationships with hyperlipidemia, atherosclerosis, and endothelial dysfunction in apolipoprotein-E knockout (ApoE-KO) mice. Ten-week-old ApoE-KO mice were fed either atherosclerotic diet (1.25% cholesterol) or normal diet. Wild type mice (C57BL/6J) served as normal controls. Fourteen weeks later, marked hyperlipidemia, atherosclerosis, endothelial dysfunction, and hearing impairment, especially in the high frequencies, had developed in ApoE-KO mice as compared with C57BL/6J mice (P < 0.001). A high positive correlation between hearing loss and the extent of atherosclerosis and plasma total cholesterol levels was found. Hearing loss, especially at high frequencies, was detected in all ApoE-KO mice. Hair cell loss mainly at the base turn, thickening of vascular intima, and lumen stenosis of the spiral modiolar artery (SMA) in cochlea were also found; these histological changes were exacerbated by the atherosclerotic diet. Furthermore, endothelial nitric oxide synthase (eNOS) in aortic wall and cochlea was distinctly reduced in ApoE-KO mice. These results demonstrate that hyperlipidemia and atherosclerosis can induce alterations in cochlear morphology and function. The stenosis of SMA, which may cause cochlear ischemia and hypoxia, endothelial dysfunction, and low eNOS activity, may contribute to hearing loss.

Objective - The majority of apoptotic cells in atherosclerotic lesions are macrophages. However, the pathogenic role of macrophage apoptosis in the development of atherosclerosis remains unclear. Elevated expression of Bax, one of the pivotal proapoptotic proteins of the Bcl-2 family, has been found in human atherosclerotic plaques. Activation of Bax also occurs in free cholesterol-loaded and oxysterol-treated mouse macrophages. In this study, we examined the effect of Bax deficiency in bone marrow-derived leukocytes on the development of atherosclerosis in low-density lipoprotein receptor-null (LDLR-/-) mice. Methods and Results - Fourteen 8-week-old male LDLR-/- mice were lethally irradiated and reconstituted with either wild-type (WT) C57BL6 or Bax-null (Bax-/-) bone marrow. Three weeks later, the mice were challenged with a Western diet for 10 weeks. No differences were found in the plasma cholesterol level between the WT and Bax-/- group. However, quantitation of cross sections from proximal aorta revealed a 49.2% increase (P=0.0259) in the mean lesion area of the Bax-/- group compared with the WT group. A 53% decrease in apoptotic macrophages in the Bax-/- group was found by TUNEL staining (P<0.05). Conclusions - The reduction of apoptotic activity in macrophages stimulates atherosclerosis in LDLR-/- mice, which is consistent with the hypothesis that macrophage apoptosis suppresses the development of atherosclerosis.

C-reactive protein (CRP) that has been conserved throughout evolution is a host-defense molecule. Its attraction towards phosphocholine-ligands, such as modified low-density lipoprotein, and apoptotic cells leads to the "masking" of these substances that have the capabilities to otherwise engage in deleterious activities. Complement activation by CRP complexes and the modulation by CRP of complement activation by its ligands add up to its beneficial effects. In the presence of CRP, production of membrane-damaging last product of the complement pathway is arrested. CRP is currently serving as an indicator of cardiovascular diseases, but to pinpoint the role of CRP in atherosclerosis, a drug that can lower cholesterol levels, but not the CRP levels, is needed for experimentation.

京都大学 / 新制・課程博士 / 博士(医学) / 甲第23607号 / 医博第4794号 / 新制||医||1055(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 溝脇 尚志, 教授 木村 剛, 教授 濵﨑 洋子 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

The accumulation of pro-inflammatory macrophages in the inflamed vascular wall is a critical step in atherogenesis. The mechanism of macrophage retention within the site of inflammation is not understood yet. High adhesion that prevents macrophage migration is one of the potential mechanisms. Previous research in our laboratory showed that integrin αDβ2 is upregulated on pro-inflammatory macrophages, promotes macrophage retention, and contributes to atherogenesis. However, a key ligand for αDβ2 within the tissue is yet to be identified, since αDβ2 does not interact with major ECM proteins, collagens, and laminins. We recently found that during acute inflammation, the oxidation of docosahexaenoic acid (DHA) leads to the generation of end product carboxyethylpyrrole (CEP), which forms an adduct with fibrinogen and albumin via ε-amino group of lysines. There is evidence that macrophages adhere to CEP-modified albumin in αDβ2-dependent manner. We continued the advancement of the proposed hypothesis that non-conserved, basic amino acids of integrin αDβ2 located near the MIDAS site of the I-domain are responsible for binding to CEP. αD I-domain and generated I-domain mutants: H272(D), K297(Q) and K309(N) were used to map the ligand binding site between integrin and CEP. Using site-directed mutagenesis, mutant αD I-domains were generated with minimal amino acid substitutions. Protein-protein binding reveals that the generated mutation of K297(Q) on the I-domain demonstrates the strong reduction of binding, while H272(D) and K309(N) did not have a significant effect on integrin binding properties. Therefore, lysine 297 located in I-domain of integrin αD, is a critical amino acid for αDβ2 binding to CEP-modified proteins. The identification of a binding site for CEP-modified proteins within αDβ2 will help to develop a blocking reagent for the treatment of the inflammatory component of atherosclerosis.

Indiana University-Purdue University Indianapolis (IUPUI) / Biofilm-related infections account for more than 75% of all microbial infections in humans. Several studies argued that the biofilm-dispersal process initiates systemic infections by causing bacteria to be released into the host. Although our knowledge of the characteristics of dispersed bacteria is still limited, it is recognized that these bacteria have different characteristics, such as higher virulence and adhesion factors, in contrast to their planktonic and sessile counterparts. Streptococcus mutans (S. mutans), which is the major pathogen in the formation of dental caries has also been detected in atherosclerotic plaques, and heart valve specimens from patients with cardiovascular diseases. In oral isolates, the frequency of S. mutans strains positive for the collagen binding protein (CBP) cnm+ gene has been estimated to be 10-20%. Tobacco use is considered to be an independent risk factor for both atherosclerosis and dental caries. Knowledge about S. mutans biofilm dispersal is lacking. Thus, studying the characteristics of dispersed bacteria is crucial to fill that gap of knowledge. We began our investigation by conducting a review of the literature on current findings about biofilm formation and dispersion of several oral and extraoral pathogens, in addition to methodologies for analyzing the dispersion phase. For this study, we identified and chose three dispersion-inducing compounds: adenosine triphosphate (ATP), cis-2-deconoic acid (CDA), and nicotine (NIC). Subsequently, the dispersion, adhesion to collagen type IV, and invasion of bovine aortic endothelial cells (BAEC) were studied using two S. mutans strains, UA159 (Cnm-) and TLJ60a (Cnm+). Both strains showed increased dispersion, adherence rates to collagen type IV, and invasion percentages of BAEC when treated with dispersion inducers compared to their control. In the ATP and NIC groups, TLJ60a (Cnm+) demonstrated greater dispersion and adherence to collagen type IV than UA159 (Cnm-). Harboring the cnm encoding gene appears to enhance S. mutans invasion of BAEC in both biofilm and dispersed cells. In the Cnm+ strain, ATP-induced dispersed cells demonstrated a consistent increase in type IV collagen adhesion and BAEC invasion rates. Therefore, it is imperative to investigate the impact of ATP secretion by damaged endothelial cells in determining S. mutans role in atherogenesis. / 2023-12-28

No description available.