Transendocardial delivery of autologous bone marrow enhances collateral perfusion and regional function in pigs with chronic experimental myocardial ischemia

OBJECTIVES

We tested the hypothesis that intramyocardial injection of autologous bone marrow (ABM) promotes collateral development in ischemic porcine myocardium. We also defined, in vitro, whether bone marrow (BM) cells secrete vascular endothelial growth factor (VEGF) and macrophage chemoattractant protein-1 (MCP-1).

BACKGROUND

The natural processes leading to collateral development are extremely complex, requiring multiple growth factors interacting in concert and in sequence. Because optimal angiogenesis may, therefore, require multiple angiogenic factors, we thought that injection of BM, which contains cells that secrete numerous angiogenic factors, might provide optimal therapeutic angiogenesis.

METHODS

Bone marrow was cultured four weeks in vitro. Conditioned medium was assayed for VEGF and MCP-1 and was added to cultured pig aortic endothelial cells (PAEC) to assess proliferation. Four weeks after left circumflex ameroid implantation, freshly aspirated ABM (n = 7) or heparinized saline (n = 7) was injected transendocardially into the ischemic zone (0.2 ml/injection at 12 sites). Echocardiography to assess myocardial thickening and microspheres to assess perfusion were performed at rest and during stress.

RESULTS

Vascular endothelial growth factor and MCP-1 concentrations increased in a time-related manner. The conditioned medium enhanced, in a dose-related manner, PAEC proliferation. Collateral flow (ischemic/normal zone X 100) improved in ABM-treated pigs (ABM: 98 +/- 14 vs. 83 +/- 12 at rest, p = 0.001; 89 +/- 18 vs. 78 +/- 12 during adenosine, p = 0.025; controls: 92 +/- 10 vs. 89 +/- 9 at rest, p = 0.49; 78 +/- 11 vs. 77 +/- 5 during adenosine, p = 0.75). Similarly, contractility increased in ABM-treated pigs (ABM: 83 +/- 21 vs. 60 +/- 32 at rest, p = 0.04; 91 +/- 44 vs. 36 +/- 43 during pacing, p = 0.056; controls: 69 +/- 48 vs. 64 +/- 46 at rest, p = 0.74; 65 +/- 56 vs. 37 +/- 56 during pacing, p = 0.23).

CONCLUSIONS

Bone marrow cells secrete angiogenic factors that induce endothelial cell proliferation and, when injected transendocardially, augment collateral perfusion and myocardial function in ischemic myocardium.

Association between prior cytomegalovirus infection and the risk of restenosis after coronary atherectomy

BACKGROUND

Restenosis occurs commonly after coronary angioplasty and atherectomy, but the causes of restenosis are poorly understood. Recently, it has been found that cytomegalovirus (CMV) DNA is present in restenotic lesions from atherectomy specimens. This and other evidence suggest that CMV may have a role in the process of restenosis.

METHODS

We prospectively studied 75 consecutive patients undergoing directional coronary atherectomy for symptomatic coronary artery disease. Before atherectomy was performed, we measured blood levels of anti-CMV IgG antibodies to determine whether previous exposure to CMV increased the risk of restenosis, as determined by coronary angiography performed six months after atherectomy.

RESULTS

After atherectomy, the mean (+/- SD) minimal luminal diameter of the target vessel was greater in the 49 patients who were seropositive for CMV than in the 26 patients who were seronegative (3.18 +/- 0.51 mm vs. 2.89 +/- 0.45 mm, P=0.01). After six months, however, the seropositive patients had a greater reduction in the luminal diameter (1.24 +/- 0.83 mm vs. 0.68 +/- 0.69 mm, P = 0.003), resulting in a significantly higher rate o restenosis in the seropositive patients (43 percent vs. 8 percent, P = 0.002). In a multivariable logistic-regression model, CMV seropositivity and the CMV titer were independently predictive of restenosis (odds ratios, 12.9 and 8.1, respectively). There was no evidence of acute infection, since the titer of anti-CMV IgG antibodies did not increase over time and tests for anti-CMV IgM antibodies were negative in all patients.

CONCLUSIONS

Prior infection with CMV is strong independent risk factor for restenosis after coronary atherectomy. If confirmed, these findings may help identify patients at risk for restenosis.

Infection and atherosclerosis: emerging mechanistic paradigms

Although definitive proof of a causal role of infection contributing to atherogenesis is lacking, multiple investigations have demonstrated that infectious agents evoke cellular and molecular changes supportive of such a role. Moreover, both Chlamydia pneumoniae and cytomegalovirus exacerbate lesion development in animal models of atherosclerosis and restenosis. The fact that multiple pathogens have been associated with atherosclerosis implies that many "atherogenic" pathogens exist, and recent data suggest that the risk of atherosclerosis conveyed by infection relates to the number of atherogenic pathogens with which an individual is infected. It also is evident that variability in host susceptibility to the atherogenic effects of pathogens exists; this variability appears to be related at least in part to whether the host can generate an immune response that successfully controls pathogen inflammatory activity and in part to the specific pattern of immune response--humoral or cellular. The latter may relate to host capacity to control pathogen activity and to a pathogen-induced autoimmune component of the atherogenic process. Additional animal and human studies are necessary to further test the validity of the infection/atherosclerosis link and to provide more insight into the mechanisms by which infection may contribute to atherosclerosis, information critical for devising strategies to reduce or eliminate any contribution to atherosclerosis caused by infection.

Therapeutic interventions for enhancing collateral development by administration of growth factors: basic principles, early results and potential hazards

The importance of spontaneously developing collateral vessels to supplement perfusion of tissue rendered ischemic by vascular obstruction was recognized many years ago. However, it was not until potent angiogenesis factors were identified, purified, and produced in sufficient quantities, that the field began its rapid development. In the early 1990s it was first shown that basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF) proteins could actually stimulate collateral flow. However, additional studies also demonstrated that the duration of exposure of the vessels to angiogenesis factors was critical, and that the administration of proteins, with their relatively brief half-lives, may pose important practical limitations. The demonstration that gene therapy can improve collateral function presents one of the solutions to the conundrum, since gene therapy can be considered a sophisticated form of a sustained delivery system. The results of several clinical trials have been reported. All involve administration of single angiogenesis agents, and most are Phase I trials. The two studies rising to Phase II status demonstrated no treatment effect on the primary end-point. It may therefore be relevant to consider that the molecular mechanisms responsible for angiogenesis are extraordinarily complex, and an optimal angiogenesis intervention may require a 'multiple factor' strategy. It is important to note that no serious side-effects ascribable to an angiogenesis agent were recognized in these trials. However, angiogenesis agents are potent molecules with multiple activities. It is therefore possible that they might occasionally cause side-effects, some serious. Among these, based on their biologic activities, are neovascularization of non-targeted tissues, expansion and induction of instability of atherogenic plaque, and growth of tumors. In summary, there is ample experimental evidence justifying an optimistic outlook relating to our eventually being successful in enhancing collateral flow to ischemic tissue in a clinical setting. However, we are not there yet, and identification of the optimal angiogenesis strategy is still unclear. Additional experimental work, in parallel with large, carefully controlled clinical trials are needed to continue the exciting advances of the last decade, and to achieve the goal of providing patients with alternative potent therapies to improve collateral flow, and thereby to alleviate their symptoms and perhaps to prolong their lives.

Infection and atherosclerosis: potential roles of pathogen burden and molecular mimicry

Infection has been implicated as a cause of atherosclerosis since the first half of the 19th century. Over the years, sporadic publications have appeared in the literature reflecting a persistent but relatively low level of research activity in this area. In the last decade, however, publications relating to this topic have increased markedly. And very recently, new epidemiological and mechanistic data relating infection to several different diseases, including atherosclerosis, have appeared, stimulating the emergence of important paradigm shifts in how we think about the causes of chronic disease. The following article reviews some of these newer concepts as they relate to a possible role of infection in atherosclerosis.

Protection from reoxygenation injury by inhibition of rac1

We demonstrate that adenoviral-mediated gene transfer of a dominant negative rac1 gene product (N17rac1) inhibits the intracellular burst of reactive oxygen species (ROS) that occurs after reoxygenation of vascular smooth muscle cells. In contrast, expression of a dominant negative ras gene (N17ras) had no effect. Challenge of control cells and cells expressing N17rac1 with a direct oxidant stress produced an equivalent increase in intracellular ROS levels and subsequent cell death. This suggests that N17rac1 expression appears to block production of harmful oxygen radicals and does not act directly or indirectly to scavenge ROS generated during reoxygenation. Expression of N17rac1 results in protection from hypoxia/reoxygenation-induced cell death in a variety of cell types including vascular smooth muscle cells, fibroblasts, endothelial cells, and ventricular myocytes. These results suggest that reoxygenation injury requires the activation of rac proteins, and that inhibition of rac-dependent pathways may be a useful strategy for the prevention of reperfusion injury in ischemic tissues.

Cytomegalovirus infection increases development of atherosclerosis in Apolipoprotein-E knockout mice

Cytomegalovirus (CMV) infection has been associated with coronary artery disease, but it is unknown whether the virus can causally contribute to atherogenesis. To determine whether the virus has this capacity, we infected an atherosclerotic-prone mouse strain (C57BL/6J apoE-/-) with murine CMV. At 14 days of age, 30 mice received CMV (30000 pfu) ip and 30 received virus free media. At 13 and 16 weeks atherosclerotic lesion size was measured from aortic sinus cross-sections. Infection did not alter plasma levels of cholesterol, triglycerides, and high density lipoprotein (HDL); however, 4 weeks after infection IFNgamma levels were elevated (infection vs control: 156+/-49 vs 50+/-22 pg/ml, P=0.04). No differences in lesion size were present at 13 weeks post infection. However, by 16 weeks mean aortic sinus lesion area (mm(2)x10(3)+/-SEM; N=75) in the CMV-infected mice was significantly greater than in uninfected mice (74+/-6 vs 57+/-6; P=0.04). CMV caused the greatest increase (34%) in lesion size in females (103+/-9 vs 77+/-10; P=0.05; N=35). These results provide additional evidence implicating CMV as a causal agent of atherosclerosis, at least in an animal model.

Fatty acids and beta-carotene in australian purslane (Portulaca oleracea) varieties

The fatty acid profile and beta-carotene content of a number of Australian varieties of purslane (Portulaca oleracea) were determined by GC and HPLC. The total fatty acid content ranged from 1.5 to 2.5 mg/g of fresh mass in leaves, 0.6 to 0.9 mg/g in stems and 80 to 170 mg/g in seeds. alpha-Linolenic acid (C18:3omega3) accounted for around 60% and 40% of the total fatty acid content in leaves and seeds, respectively. Longer-chain omega-3 fatty acids were not detected. The beta-carotene content ranged from 22 to 30 mg/g fresh mass in leaves. These results indicate that Australian purslane varieties are a rich source of alpha-linolenic acid and beta-carotene.

The immediate early gene products of human cytomegalovirus increase vascular smooth muscle cell migration, proliferation, and expression of PDGF beta-receptor

Evidence suggests that human cytomegalovirus (HCMV) infection contributes to the development of atherosclerosis and restenosis. Because smooth muscle cell (SMC) proliferation and migration are crucial events of both processes, and because PDGF beta-receptor modulates SMC migration, we determined whether HCMV infection affects SMC proliferation, migration, and PDGF beta-receptor expression. We employed a SMC model in which HCMV infection leads to expression of only the immediate early (IE) HCMV gene products-HCMV infection of rat SMCs. We found that HCMV infection significantly (i) increased SMC proliferation (from 0.9 x 10(6) +/- 0.024 x 10(6) to 1.4 x 10(6) +/- 0.051 x 10(6) cells/well, p < 0.001); (ii) augmented SMC migration toward PDGF (from 64 +/- 37 to 116 +/- 51 cells/high power field; p < 0.01); and (iii) enhanced PDGF beta-receptor expression in a time-dependent fashion. We conclude that HCMV infection of rat SMCs increases SMC proliferation, migration, and PDGF beta-receptor expression. These findings identify further mechanisms by which CMV may contribute to the development of atherosclerosis and restenosis.

Human cytomegalovirus increases modified low density lipoprotein uptake and scavenger receptor mRNA expression in vascular smooth muscle cells

Evidence suggests a possible role for human cytomegalovirus (HCMV) in the development of arteriosclerosis. One of the earliest events in plaque formation is the accumulation of lipid-laden foam cells, derived from macrophages and smooth muscle cells (SMCs). The lipid accumulation that occurs depends upon the uptake of oxidized LDL (Ox-LDL), a process in which the scavenger receptor (SR) has been postulated to play an important role. We therefore examined the effects of HCMV on this process. We demonstrate that HCMV infection of human SMCs increases modified LDL uptake and stimulates class A SR gene (SR-A) mRNA expression. In addition, infection of rat SMCs with HCMV, which causes immediate early gene expression (IE72/IE84), but no early or late HCMV gene products and no cytopathic effects, also increases SMC uptake of Ox-LDL and acetylated LDL, with either effect blocked by an excess of either cold Ox-LDL or acetylated-LDL, and by fucoidin, an SR competitor. Cotransfection of an IE72, but not an IE84, expression plasmid and a plasmid containing a Class A SR promoter/reporter gene construct enhances SR promoter activity. Since increased Ox-LDL uptake is believed to play an important role in arteriosclerosis, these results provide a link between HCMV infection and arteriosclerotic plaque formation.

A case-control study of hepatitis B and C virus infection as risk factors for hepatocellular carcinoma in Henan, China

BACKGROUND

Hepatocellular carcinoma (HCC) is one of the most common cancers in the world and is particularly prevalent in China. China is also a hyperendemic area for hepatitis B virus (HBV) infection. Although a strong association between HBV infection and HCC has been established previously, the role of hepatitis C virus (HCV) infection and the interaction between HBV and HCV in the development of HCC has not been adequately explored. The major objective of this study is to determine the relationship between HBV or HCV infection and HCC by use of case-control study in Henan, China.

METHOD

In all, 152 HCC patients and 115 control patients were collected from four hospitals in Henan, China between January 1994 and October 1995. The demographic characteristics of the two groups were comparable. In further analysis, a 1:1 pair-matched case-control study was performed. Of 152 HCC patients, 113 were randomly selected to be pair-matched by sex and age (+/-5 years) to controls with non-hepatic disease. All the cases and controls were interviewed during hospitalization by two specially trained interviewers using a standard questionnaire. All sera were tested for HBV and HCV markers. Odds ratios (OR) and 95% CI for HCC risk factors were calculated by logistic regression model controlling for possible confounding factors such as sex and age. The multivariate analysis was done on the basis of the univariate analysis.

RESULTS

The results of this study indicated that the prevalence of hepatitis B surface antigen (HBsAg) and antibody to HCV (anti-HCV) were much higher in HCC patients (63.2% and 11.2% respectively) than in the control patients (5.2%, 3.5%). The difference between two groups was significant (P < 0.05). Risk factor analysis revealed that both HBV and HCV infection were important factors for HCC in Henan, China and HBV appeared to have a key role in the development of HCC. Odds ratios of HBsAg and HBV infection were 28.82 (95% CI: 11.18-78.78) and 31.22 (95% CI: 13.86-72.15), respectively. Moreover, the risk of developing HCC increased significantly and showed an additive effect when both viral markers of HBV and HCV infection were considered (OR = 42.85). Results from the 1:1 pair-matched case-control study also showed that HBV infection was an important risk factor for HCC, which was consistent with the results from the group-matched case-control study.

CONCLUSION

This is the first reported case-control study of HCC in Henan, China. This study provides further evidence that chronic HBV infection is strongly associated with the development of HCC among this population. Our results have demonstrated that HCV and HBV infection are independent and probably additive risk factors for HCC.

Cytomegalovirus infection of rats increases the neointimal response to vascular injury without consistent evidence of direct infection of the vascular wall

BACKGROUND

Previous studies suggest that infection may play a role in restenosis and atherogenesis; cytomegalovirus (CMV) is one of the implicated pathogens. To determine a potential causal role of CMV in these disease processes, we assessed whether CMV infection increases the neointimal response to injury of the rat carotid artery.

METHODS AND RESULTS

Carotid injury was performed on 60 rats; immediately thereafter, 30 rats were infected with rat CMV, and the other 30 were mock-infected. Six weeks later, rats were euthanized, and the salivary glands, spleen, and carotid arteries were harvested. CMV infection was associated with significant exacerbation of the neointimal response to injury (neointimal to medial ratio 0.81+/-0. 59 versus 0.31+/-0.38 in CMV-infected versus control rats; P<0.0001). This occurred despite absence of infectious virus from vascular tissues and detection of CMV DNA by polymerase chain reaction in the injured artery only at day 3 after infection. Persistent distant infection, associated with systemic cytokine response, was evidenced by isolation of infectious virus from homogenates of both salivary glands and spleen and by higher serum levels of interleukin (IL)-2 and IL-4 (but not interferon-gamma and tumor necrosis factor-alpha) in infected versus noninfected rats.

CONCLUSIONS

CMV infection of immunocompetent adult rats increases the neointimal response to vascular injury, suggesting that CMV may play a causal role in atherosclerosis/restenosis. Importantly, this CMV-induced response occurs even without the presence of virus in the vascular wall, suggesting that inflammatory and immune responses to infection of nonvascular tissues may contribute to the vascular response to injury.

Does seeding density affectin vitro mineral nodules formation in novel composite scaffolds?

This study investigated the human alveolar osteoblasts (AOs) proliferation and extracellular matrix formation at seeding density of 0.05, 0.1, 0.2, 0.4, and 0.8 million (M) per 3x4x4 mm3 on medical grade polycaprolactone-tricalcium phosphate (mPCL-TCP) scaffolds designed for bone regeneration. Over 80-90% of the initial seeded cells were retained in the scaffolds after 24 h. AOs bridged over pores at density of 0.2M/scaffold and below, but formed cell balls at density of 0.4M/scaffold and above. At seeding density of 0.2M and below, cell proliferation increased with time having DNA content peaked to 1600 ng/scaffold at day 21 and 28, respectively, whereas at 0.4 and 0.8M, the corresponding DNA content decreased to 1600 ng in 28 days. At day 7, higher alkaline phosphatase (ALP) activity and higher osteocalcin (OCN) secretion were detected at 0.2M/scaffold and below. After 28 days, multilayered cell-sheet formation and collagen fibers were observed at all densities. ALP and OCN in matrix and mineral nodules were found mainly at the border of AOs-scaffold construct. These findings demonstrated that the density of 0.2M and below per 3 x 4 x 4 mm(3) scaffold resulted in better cell proliferation and extracellular matrix synthesis, potentially resulting in better mineralized tissue formation.

Lack of association of restenosis following coronary angioplasty with elevated C-reactive protein levels or seropositivity to Chlamydia pneumoniae

Seventy-five consecutive patients undergoing directional coronary atherectomy were evaluated by measuring anti-Chlamydia immunoglobulin G and anticytomegalovirus immunoglobulin G antibodies, and serum levels of C-reactive proteins (before atherectomy). The results showed that although both Chlamydia infection and elevated C-reactive protein levels are associated with coronary artery disease and coronary artery disease events, neither of these appears to play a role in the development of restenosis.

Suppression of the development of experimentally induced uterine adenomyosis by a novel matrix metalloproteinase inhibitor, ONO-4817, in mice

The inhibitory effects of a novel, orally active matrix metalloproteinase (MMP) inhibitor, ONO-4817, on the development of uterine adenomyosis induced experimentally by pituitary grafting were examined in mice. Mice were given transplants of isologous anterior pituitary glands (PGs) into the right uterine lumen at 7 weeks of age and were fed chow containing 0.1% to 1.0% ONO-4817 from 8 to 14 weeks of age. Mice treated with 0.3% or 1.0% ONO-4817 showed a significantly lower incidence of the development of adenomyosis than vehicle-treated mice. To evaluate the inhibitory effects of ONO-4817 on the progression of the invasion of the adenomyotic tissues, mice receiving PG grafts at 7 weeks of age were treated with 1.0% ONO-4817 from 13 to 17 weeks of age. The degree of pathological progression of adenomyosis was graded from 1 to 5 in increments of 1. The degree of the progression of the lesion was less in the uteri exposed to ONO-4817 (2.71 +/- 0.93) than in the uteri not exposed to the inhibitor (4.33 +/- 0.75). Finally, the invasiveness of endometrial stromal cells obtained from adenomyotic uteri into Matrigel consisting mainly of type IV collagen and laminin was examined using an invasion assay. The assay showed that the treatment with ONO-4817 markedly suppressed the invasion of the stromal cells of the adenomyotic uteri into the gel. These results indicate that ONO-4817 may be an effective inhibitor of the development of adenomyosis.

Autoantibody detection to tumor-associated antigens of P53, IMP1, P16, cyclin B1, P62, C-myc, Survivn, and Koc for the screening of high-risk subjects and early detection of esophageal squamous cell carcinoma

The aim of this study was to evaluate the diagnostic values by detecting sera autoantibodies to eight tumor-associated antigens (TAAs) of P53, IMP1, P16, cyclin B1, P62, C-myc, Survivn and Koc full-length recombinant proteins for the screening of high-risk subjects and early detection of esophageal squamous cell carcinoma (ESCC). Enzyme-linked immunosorbent assay was used to detect autoantibodies against the eight selected TAAs in 567 sera samples from four groups, including 200 individuals with normal esophageal epithelia (NOR), 214 patients with esophageal basal cell hyperplasia (BCH), 65 patients with esophageal dysplasia (DYS), and 88 patients with ESCC. In addition, the expression of the eight antigens in esophageal tissues was analyzed by immunohistochemistry. Statistically significant distribution differences were identified among the four groups for each of the individual autoantibodies to six TAAs (P53, IMP1, P16, cyclin B1, P62, and C-myc); the detection rates of antoantibodies were positively correlated with the progression of ESCC. When autoantibody assay successively accumulated to six TAAs (P53, IMP1, P16, cyclin B1, P62, and C-myc), a stepwise increased detection frequency of autoantibodies was found in the four sera groups (6% in NOR, 18% in BCH, 38% in DYS, and 64% in ESCC, respectively), the risks to BHC, DYS, and ESCC steadily increased about 3-, 9-, and 27-folds. The sensitivity and the specificity for autoantibodies against the six TAAs in diagnosing ESCC reached up to 64% and 94%, respectively. The area under the receiver operating characteristic curve for the six anti-TAA autoantibodies was 0.78 (95% confidence interval 0.74-0.83). No more increasing in sensitivity was found with the addition of new anti-TAA autoantibodies. A combination detection of autoantibodies to TAAs might distinguish ESCC patients from normal individuals and the patients with esophageal precancerous lesions.

Methionine and choline supply alter transmethylation, transsulfuration, and cytidine 5'-diphosphocholine pathways to different extents in isolated primary liver cells from dairy cows

Insufficient supply of Met and choline (Chol) around parturition could compromise hepatic metabolism and milk protein synthesis in dairy cows. Mechanistic responses associated with supply of Met or Chol in primary liver cells enriched with hepatocytes (PHEP) from cows have not been thoroughly ascertained. Objectives were to isolate and culture PHEP to examine abundance of genes and proteins related to transmethylation, transsulfuration, and cytidine 5'-diphosphocholine (CDP-choline) pathways in response to Met or Chol. The PHEP were isolated from liver biopsies of Holstein cows (160 d in lactation). More than 90% of isolated cells stained positively for the hepatocyte marker cytokeratin 18. Cytochrome P450 (CYP1A1) mRNA abundance was only detectable in the PHEP and liver tissue compared with mammary tissue. Furthermore, in response to exogenous Met (80 μM vs. control) PHEP secreted greater amounts of albumin and urea. Subsequently, PHEP were cultured with Met (40 μM) or Chol (80 mg/dL) for 24 h. Compared with control or Chol, mRNA and protein abundance of methionine adenosyltransferase 1A (MAT1A) and phosphatidylethanolamine methyltransferase (PEMT) were greater in PHEP treated with Met. The mRNA abundance of S-adenosylhomocysteine hydrolase (SAHH), betaine-homocysteine methyltransferase (BHMT), and sarcosine dehydrogenase (SARDH) was greater in Met-treated PHEP compared with control or Chol. Compared with control, greater expression of 5-methyltetrahydrofolate-homocysteine methyltransferase (MTR), betaine aldehyde dehydrogenase (BADH), and choline dehydrogenase (CHDH) was observed in cells supplemented with Met and Chol. However, Chol led to the greatest mRNA abundance of CHDH. Abundance of choline kinase α (CHKA), choline kinase β (CHKB), phosphate cytidylyltransferase 1 α (PCYT1A), and choline/ethanolamine phosphotransferase 1 (CEPT1) in the CDP-choline pathway was greater in PHEP treated with Chol compared with control or Met. In the transsulfuration pathway, mRNA and protein abundance of cystathionine β-synthase (CBS) was greater in PHEP treated with Met compared with control or Chol. Similarly, abundance of cysteine sulfinic acid decarboxylase (CSAD), glutamate-cysteine ligase, catalytic subunit (GCLC), and glutathione reductase (GSR) was greater in response to Met compared with control or Chol. Overall, these findings suggest that transmethylation and transsulfuration in dairy cow primary liver cells are more responsive to Met supply, whereas the CDP-choline pathway is more responsive to Chol supply. The relevance of these data in vivo merit further study.

CTC1 increases the radioresistance of human melanoma cells by inhibiting telomere shortening and apoptosis

Melanoma has traditionally been viewed as a radioresistant cancer. However, recent studies suggest that under certain clinical circumstances, radiotherapy may play a significant role in the treatment of melanoma. Previous studies have demonstrated that telomere length is a hallmark of radiosensitivity. The newly discovered mammalian CTC1-STN1-TEN1 (CST) complex has been demonstrated to be an important telomere maintenance factor. In this study, by establishing a radiosensitive/radioresistant human melanoma cell model, MDA-MB-435/MDA-MB-435R, we aimed to investigate the association of CTC1 expression with radiosensitivity in human melanoma cell lines, and to elucidate the possible underlying mechanisms. We found that CTC1 mRNA and protein levels were markedly increased in the MDA-MB-435R cells compared with the MDA-MB-435 cells. Moreover, the downregulation of CTC1 enhanced radiosensitivity, induced DNA damage and promoted telomere shortening and apoptosis in both cell lines. Taken together, our findings suggest that CTC1 increases the radioresistance of human melanoma cells by inhibiting telomere shortening and apoptosis. Thus, CTC1 may be an attractive target gene for the treatment of human melanoma.

Chronic non-vascular cytomegalovirus infection: effects on the neointimal response to experimental vascular injury

OBJECTIVE

Epidemiologic and mechanistic evidence implicates a role for cytomegalovirus (CMV) in atherogenesis. Recently, we demonstrated that CMV has the capacity to causally contribute to atherogenesis; acute infection of rats with rat CMV (RCMV) 1 day after carotid artery injury increased neointimal accumulation. Importantly, in the injured vessel infectious virus could not be detected and viral genome was present only transiently, suggesting that additional mechanisms play a role in the virus-induced exacerbation of the vascular injury response other than the changes caused by direct infection of vessel wall cells. The present investigation was designed to determine whether chronic persistent RCMV infection, more relevant to the clinical situation, also exacerbates the response to injury and, if so, whether similar mechanisms are operative.

METHODS

Sixty 3-week-old male Spraque-Dawley rats received an i.p. injection of either 10(6) TCID50 RCMV (Priscott strain) or normal saline. The left carotid artery was balloon-injured 3 months after infection. Rats were killed 6 weeks later. This model produces persistent infection, as demonstrated by presence of infectious virus in the salivary glands at time of sacrifice.

RESULTS

The neointima to media (N/M) ratio of the injured vessel was 41% greater in the RCMV-infected than in control rats (1.40 +/- 0.48 vs. 0.99 +/- 0.45; P = 0.003). The aorta never contained infectious RCMV, and exhibited RCMV DNA, detected by PCR, only transiently. The persistent infection of non-vascular tissues was associated with increased serum levels of IL-2, IL-4 and IFN-gamma.

CONCLUSIONS

CMV infection of young rats causes persistent infection of non-vascular tissues and increased cytokine levels. The neointimal response to subsequent vascular injury is increased, despite absence of virus from the vessel wall. These findings, as in acute infection following vascular injury, suggest that inflammatory and immune responses to chronic persistent CMV infection contribute to an exaggerated response to vascular injury.

The effects of aging on the strength of surround suppression of receptive field of V1 cells in monkeys

The surround suppression of the receptive field is important for basic visual information processing, such as orientation specificity. To date, the effects of aging on the strength of surround suppression are not clear. To address this issue, we carried out extracellular single-unit studies of the receptive field properties of cells in the primary visual cortex (area V1) in young and old rhesus (Macaca mulatta) monkeys. When presented with the oriented central stimulus, we found that cells in old animals showed reduced orientation and direction selectivity compared with those in young animals. When presented with the oriented central stimulus together with the optimal surround stimulus, more selective cells {orientation bias (OB) >/=0.1; a bias of 0.1 is significant at the P<0.005 level} in animals of both ages showed reduced orientation selectivity compared with the experiment that presented only the oriented central stimulus. When presented with the optimal central stimulus together with the oriented surround stimulus, cells in old animals showed reduced orientation and direction selectivity compared with young animals. Moreover, broadly tuned cells (OB<0.1) in old animals exhibited significantly reduced suppression indices that quantified the strength of the surround suppression of the receptive field, when compared with those in young animals. These results suggest that aging may seriously affect the surround suppression of the receptive field of V1 cells. Thus, the decreased strength of surround suppression of the receptive field may be one possible reason for the decreased stimulus selectivity of V1 cells previously found in the senescent brain. This work will contribute to an understanding of the physiological mechanisms mediating surround suppression of the receptive field.

Serum of cytomegalovirus-infected mice induces monocyte chemoattractant protein-1 expression by endothelial cells

Inflammation plays a central role in atherogenesis. It was hypothesized that infection of apolipoprotein E-deficient mice with murine cytomegalovirus (MCMV) increases serum levels of proinflammatory cytokines, which may induce "proatherosclerotic" changes in endothelial cells (ECs). Serum samples were collected from uninfected and infected mice. ELISA was used to determine cytokine serum levels and monocyte chemoattractant protein-1 (MCP-1) levels in the supernatant of mouse ECs incubated with serum-containing medium. Serum samples from infected mice induced MCP-1 expression by ECs. These serum samples contain interferon (IFN)-gamma, whereas IFN-gamma was undetectable in serum samples from uninfected mice. Preincubating infected mouse serum with anti-IFN-gamma monoclonal antibody significantly decreased serum-induced EC expression of MCP-1. Thus, MCMV infection increases IFN-gamma serum levels, such serum can induce MCP-1 in ECs, and the serum-induced MCP-1 expression is due, at least in part, to IFN-gamma. If these changes in EC function also occur in vivo in response to infection, they could exacerbate atherogenesis.

Interaction between TP53 and XRCC1 increases susceptibility to cervical cancer development: a case control study

BACKGROUND

Cervical cancer is the 4th highest cause of female reproductive tract malignancies. Multiple loci have been identified as important determinant factors for tumor susceptibility. In this report, we aimed to explore the roles of gene polymorphisms affecting x-ray repair cross complementing 1 (XRCC1), the tumor protein p53 (TP53), and fibroblast growth factor receptor 3 (FGFR3) in the context of susceptibility to cervical cancer. Additionally, we assessed the impact of single nucleotide polymorphism-single nucleotide polymorphism (SNP-SNP) interaction of these three genes in the context of cervical cancer risk in Chinese women.

METHODS

A case-control study consisted of 340 women located in Chongqing. Of these women, 121 were diagnosed with cervical cancer, 118 served as healthy controls, and 101 were specifically recruited elderly patients above the age of 80 who showed no history of cervical cancer. Three SNPs (XRCC1 rs25487, TP53 rs1042522, and FGFR3 rs121913483) were examined using mutation analysis of mismatch amplification PCR (MAMA-PCR) on samples obtained from peripheral blood.

RESULTS

Our results indicated that females from southwestern China all exhibited a wild-type phenotype at FGFR3 rs121913483. We also observed that the rs25487 mutation was significantly increased within the cervical cancer population. A 2-locus SNP-SNP interaction pattern (rs25487 and rs1042522) was significantly associated with cervical cancer risk (cases vs. negative controls: OR = 4.63, 95% CI = 1.83-11.75; cases vs. elderly group: OR = 17.61, 95% CI = 4.34-71.50).

CONCLUSIONS

This is the first study to identify a novel interaction between the XRCC1 and TP53 genes that is highly associated with susceptibility to cervical cancer risk in a female population in southwestern China.

Aberrant DNA methylation of MGMT and hMLH1 genes in prediction of gastric cancer

We aimed to explore the association between aberrant DNA methylation of the O(6)-methylguanine-DNA methyltransferase (MGMT) and human mutL homolog 1 (hMLH1) genes with gastric cancer. A total of 283 gastric cancer patients who were confirmed by pathological diagnosis were included in our study. Aberrant DNA methylation of MGMT and hMLH1 were detected. The proportions of DNA hypermethylation in MGMT and hMLH1 in cancer tissues were significantly higher than those in remote normal-appearing tissues. The DNA hypermethylation of MGMT was correlated with the tumor-necrosis-metastasis stage in gastric cancer tissues. Results showed that individuals with gastric cancer in the N1 and M1 stages had a significantly higher risk of DNA hypermethylation of MGMT in cancer tissues [odds ratio (OR) = 1.97, 95% confidence interval (CI) = 1.15-3.37 for the N1 stage; OR (95%CI) = 5.39 (2.08-14.98) for the M1 stage]. In conclusion, we found that aberrant hypermethylation of MGMT could be a predictive biomarker for detecting gastric cancer.