The reduced expression and aberrant methylation of p16(INK4a) in chromate workers with lung cancer.

STUDY OBJECTIVES: It is known that chromium is one of the important inhaled carcinogens that cause lung cancer. Our previous studies revealed a variety of genetic changes in lung cancers from chromate-exposed workers (chromate lung cancer). However, the epigenetic effects of chromium are not understood. MATERIALS AND METHODS: We investigated the methylation of the p16 gene using a methylation-specific PCR method in 30 chromate lung cancers and 38 non-chromate lung cancers, and the expression of the p16 protein using immunohistochemistry in 25 chromate lung cancers. RESULTS: Ten (33%) chromate lung cancers showed methylation of the p16 promoter region. On the other hand, 10 (26%) of the non-chromate lung cancers also showed it. The frequency of p16 methylation in non-chromate lung cancer was 0%, 33% and 30% for low (< or =600), moderate (<600, >1000) and high (> or =1000) Brinkman indexes, respectively. However, the frequency of p16 methylation in chromate lung cancer was constant, irrespective of the Brinkman index. In chromate lung cancer, patients with chromate exposure of less than 15 years never had p16 methylation, while 40% (> or =25 years) or 43% (> or =15, <25 years) of patients with chromate exposure of more than 15 years did. In chromate lung cancer, chromate exposure, not smoking, mainly influenced the p16 methylation. Most of the chromate lung cancers with p16 methylation (85.7%) showed repression of the p16 protein. CONCLUSIONS: We speculate that not only genetic but also epigenetic alterations are involved in the carcinogenesis due to chromium.

Matrix metalloproteinase inhibitor MMI-166 inhibits lymphogenous metastasis in an orthotopically implanted model of lung cancer.

Matrix metalloproteinases (MMP) are considered to be critically involved in tumor invasion and the metastasis of various cancers. MMI-166 is a selective inhibitor of matrix metalloproteinase (MMP-2, MMP-9, and MMP-14). The purpose of this study was to evaluate the effects of MMI-166 on both the growth of the implanted tumor and the lymph node metastasis of the mediastinum and prolonging the life span, using an orthotopic implantation model of the Ma44-3 cancer cell line. We examined the anti-invasive effect of MMI-166 in lung cancer cell lines using an in vitro invasion assay. Next, we examined the anticancer effect of MMI-166 in vivo. MMI-166 (200 mg/kg body weight) or a vehicle was administered orally to the orthotopically implanted lung cancer model. MMI-166 dose-dependently inhibited the invasion of cancer cell lines with expressions of MMP-2 and/or MMP-9 in vitro. In vivo, MMI-166 significantly inhibited mediastinal lymph node metastasis in this orthotopic model (weight of the mediastinum: control, 0.089 +/- 0.009 versus MMI-166, 0.069 +/- 0.008 mg; P = 0.005; metastatic area: control, 93,495 +/- 55,747 versus MMI-166, 22,747 +/- 17,478 pixels; P = 0.045). MMI-166 prolonged the life span by 6 days in median survival time in the orthotopically implanted model (P = 0.039). These results showed that MMI-166 could possibly inhibit lymph node metastasis and prolong the life span in lung cancer patients.

Randomized controlled trial comparing oral doxifluridine plus oral cyclophosphamide with doxifluridine alone in women with node-positive breast cancer after primary surgery.

PURPOSE: We compared the therapeutic usefulness of doxifluridine (5'-DFUR) alone and a combination of 5'-DFUR plus cyclophosphamide (CPM), both of which are considered effective against advanced and recurrent breast cancer, to determine which treatment is more beneficial as postoperative adjuvant chemotherapy. PATIENTS AND METHODS: A total of 1,131 women with node-positive primary breast cancer were randomly assigned after primary surgery to receive 5'-DFUR alone or 5'-DFUR plus CPM. All patients initially received 5'-DFUR in an oral dose of 1,200 mg/d for 4 weeks, starting 4 weeks after surgery. Chemotherapy was then not given for 2 weeks. Patients in the 5'-DFUR group subsequently received five 4-week cycles of treatment consisting of oral 5'-DFUR (1,200 mg/d) for the first 2 weeks and no chemotherapy for the next 2 weeks. Those assigned to the 5'-DFUR plus CPM group also received oral CPM 100 mg/d for the first 2 weeks and no chemotherapy for the next 2 weeks. Women 50 years or older concurrently received 20 mg/d of tamoxifen for 2 years in both groups. RESULTS: Of the 1,088 eligible women, 546 were assigned to receive 5'-DFUR alone and 542 were assigned to receive 5'-DFUR plus CPM. Overall disease-free survival was significantly better in women who received 5'-DFUR plus CPM than in those who received 5'-DFUR alone (log-rank test, P =.021). Toxic effects occurred in 20.0% of patients (109 of 546) in the 5'-DFUR group and 32.3% of patients (175 of 542) in the 5'-DFUR plus CPM group (chi(2) test, P <.001). CONCLUSION: Combination therapy with 5'-DFUR plus CPM is more effective in preventing recurrence than 5'-DFUR alone.

Thymidylate synthase and dihydropyrimidine dehydrogenase in non-small cell lung cancer: relationship between mRNA expression and activity.

BACKGROUND: UFT (Tegafur + Uracil) has been reported to be effective for postoperative adjuvant chemotherapy of non-small cell lung cancer (NSCLC) in a randomized prospective study. Recently, many clinical studies have demonstrated that UFT is effective for cancer with a low activity of thymidylate synthase (TS) and dihydropyrimidine dehydrogenase (DPD). In the present study, we investigated TS and DPD activity in resected tumors and corresponding normal lungs and the relationship between the activity and the mRNA expression of TS and DPD in NSCLC. MATERIALS AND METHODS: Seventy-seven patients underwent complete surgical resection and lymph node dissection for NSCLC. The activity of TS was determined by the FdUMP binding assay combined with gel filtration. The activity of DPD was determined by radio-enzymatic assay. Tumor tissues and their paired non-cancerous tissues were assayed. Furthermore, the mRNA expressions of TS and DPD were examined by real-time RT-PCR. RESULTS: The mean TS and DPD activities in NSCLC were approximately 2.4-fold and 5-fold of those in normal lungs. The mean TS and DPD activities of NSCLC were 0.099 pmol/mg and 407 pmol/mg/min, respectively. Although both TS and DPD activities showed a tendency to be high for adenocarcinoma, there was no significant difference between TS and/or DPD activities and any clinical findings (age, gender, stage and histological type). The mRNA expression of DPD was correlated with DPD activity (rs=0.846, p<0.001). The mRNA expression of TS was weakly correlated with TS activity (rs=0.757, p<0.001). CONCLUSION: TS and DPD activities in NSCLC were higher than those in normal lungs. Assay of DPD mRNA and TS mRNA by real-time RT-PCR can be used as an indicator for the use of UFT.

Myasthenia gravis appearing after thymectomy for thymoma.

OBJECTIVE: A few thymoma patients without myasthenia gravis (MG) have been observed to develop MG after total removal of the thymoma (postoperative MG). However, the cause of this is not yet known because of the rarity of postoperative MG patients. This study evaluated the clinical characteristics of the 8 postoperative MG patients. METHODS: We compiled 1089 thymoma patients treated between 1990 and 1994 in 115 institutes in Japan, and found 8 cases of postoperative MG. RESULTS: Postoperative MG was found in 8 (0.97%) of 827 thymoma patients without preoperative MG. The postoperative MG patients included 1 male and 7 females, with a mean age of 50.5+/-15.0 years. The thymoma was completely resected in all cases. The surgical method used was extended thymectomy in 2 cases and thymothymectomy in 6 cases. There were 2 cases (0.7%) of postoperative MG in the extended thymectomy group (n = 275), 6 (1.9%) in the thymothymectomy group (n = 321), and none in the tumor resection group (n = 137). The interval between thymectomy and the onset of postoperative MG varied (6 days-45 months, 19.3+/-16.5 months). The type of MG was ocular in 2 cases and general in 5 cases, according to the modified Osserman classification. The postoperative MG was responsive to anti-cholinesterase compounds and/or steroids. The improvement rate was 86%. CONCLUSIONS: Postoperative MG was present in about 1% of the patients who underwent total thymoma resection. Resection of the thymus gland does not prevent postoperative MG.

The effect of adjuvant 5'-deoxy-5-fluorouridine in early stage breast cancer patients: results from a multicenter randomized controlled trial.

To assess the efficacy of 5'-DFUR, an intermediate of capecitabine, for adjuvant treatment of early breast cancer, we conducted an open-labeled multi-center randomized controlled trial to compare postoperative 5'-DFUR treatment with surgery alone. We enrolled 1217 primary breast cancer patients and randomly assigned them into two treatment groups; one received six-month postoperative 5'-DFUR treatment by consecutive or intermittent administration, and the other surgery alone. Follow-up surveys were conducted once a year for all subjects simultaneously and examined their outcome/presence or absence of the cancer recurrence. The central study committee reviewed all follow-up data and judged the recurrence data to be used for the analysis. Eight-year follow-up data showed no significant differences in relapse-free and overall survival between the two groups, and 5'-DFUR treatment regimen showed an extremely high tolerance. Possible explanations are discussed for the finding of no significant survival difference between adjuvant 6-month 5'-DFUR monotherapy and surgery alone in early breast cancer.

Progressive increase of CD4(+)/CD45RC(-) lymphocytes after allograft rat lung transplantation: a marker of acute rejection.

BACKGROUND: Acute rejection remains one the most serious problems in lung transplantation. Although biopsy has been used for assessing the dysfunction of grafts, it is difficult to determine rejection at an early stage. Lymphocyte infiltration and activation play an important role in acute rejection of transplanted organs, and the dynamic change of lymphocyte subpopulations might be a marker to determine graft rejection after lung transplantation. METHODS: A rat lung transplant model was used. Graft-infiltrating lymphocytes in lung tissues were examined by means of histology, and isolated cells were analyzed by means of flow cytometry. Phenotypes of lymphocytes in the regional and remote lymph nodes, spleen, peripheral blood, and bronchoalveolar lavage fluid were also measured by means of flow cytometry. RESULTS: After allograft transplantation, increased lymphocytes were seen in allografts but not in isografts. In allografts the percentage of T cells increased from day 1 to day 5, whereas that of B cells was decreased. The CD4(+)/CD8(+) ratio decreased in allografts. The proportion of CD4(+)/CD45RC(-) cells increased in the allografts, which was mainly due to the increase of CD45RC(-) cells in the total CD4(+) cells. Similar changes were found in regional mediastinal lymph nodes but not in the mesenteric lymph nodes, spleen, or peripheral blood. Thus this is a specific response to lung allografts. Importantly, CD45RC(-) cells were significantly increased in the bronchoalveolar lavage fluid. CONCLUSION: Significant change of lymphocyte subpopulations is a sign of lymphocyte activation. Increased CD4(+)/CD45RC(-) cells in lung allografts could be an early marker of acute rejection, which can be examined by means of lung lavage and flow cytometry.

Therapy for thymic epithelial tumors: a clinical study of 1,320 patients from Japan.

BACKGROUND: Surgery remains the mainstay of treatment for thymic epithelial tumors, and radiation and chemotherapy also have been applied widely as adjuvant and palliative procedures. METHODS: We compiled records of 1,320 patients with thymic epithelial tumors who were treated from 1990 to 1994 in 115 institutes certified as special institutes for general thoracic surgery by The Japanese Association for Chest Surgery. RESULTS: Patients with stage I thymoma were treated with only surgery, and patients with stage II and III thymoma and thymic carcinoid underwent surgery and additional radiotherapy. Patients with stage IV thymoma and thymic carcinoma were treated with radiation or chemotherapy. The Masaoka clinical stage is an excellent predictor of the prognosis of thymoma and thymic carcinoma, but not thymic carcinoid. In stage III and IV thymoma, the 5-year survival rates of total resection, subtotal resection, and inoperable groups were 93%, 64%, and 36%, respectively. On the other hand, in thymic carcinoma, the 5-year survival rates of total resection, subtotal resection, and inoperable groups were 67%, 30%, and 24%, respectively. Prophylactic mediastinal radiotherapy could not prevent local recurrences effectively in patients with totally resected stage II and III thymoma. Adjuvant therapy including radiation or chemotherapy did not improve the prognosis in patients with totally resected III and VI thymoma and thymic carcinoma. CONCLUSIONS: Total resection is the most important factor in the treatment of thymic epithelial tumors. There is value in debulking surgery in invasive thymoma, but not in thymic carcinoma. We doubt that adjuvant therapy is valuable for patients with totally resected invasive thymoma and thymic carcinoma.

Lymphogenous and hematogenous metastasis of thymic epithelial tumors.

BACKGROUND: A TNM classification has been established for various tumors. However, the TNM classification of thymic epithelial tumor has not been established yet. METHODS: We received replies to a questionnaire on thymic epithelial tumors from 115 institutes. We compiled a database of 1,320 patients with thymic epithelial tumor (1,093 thymomas, 186 thymic carcinomas, and 41 thymic carcinoids) who were treated between 1990 and 1994. We used a tentative TNM classification of thymoma presented by Yamakawa and associates in 1991. The regional lymph nodes of the thymus were classified into three groups: anterior mediastinal lymph nodes (N1), intrathoracic lymph nodes (N2), and extrathoracic lymph nodes (N3). RESULTS: The rate of lymphogenous metastasis in thymoma, thymic carcinoma, and thymic carcinoid was 1.8%, 27%, and 28%, respectively. Most tumors with lymph node metastasis metastasized to N1 (thymoma, 90%; thymic carcinoma, 69%; thymic carcinoid, 91%). The 5-year survival rates of N0, N1, and N2 thymoma were 96%, 62%, and 20%, respectively. The 5-year survival rates of N0, N1(,) N2, and N3 thymic carcinoma were 56%, 42%, 29%, and 19%, respectively. The 5-year survival rates of M0 and M1 thymoma were 95% and 57%. The 5-year survival rates of M0 and M1 thymic carcinoma were 51% and 35%. Multivariate analysis demonstrated that survival of patients with thymoma was dependent on the clinical stage of Masaoka and complete resection. In thymic carcinoma, survival was dependent on lymph node metastasis and complete resection. CONCLUSIONS: The N factor was one of the predictors of survival in thymoma and thymic carcinoma. However, M factor showed less influence on survival than T or N factors.

WHO histologic classification is a prognostic indicator in thymoma.

BACKGROUND: The histologic classification of thymoma has remained a subject of controversy for many years. In 1999, the World Health Organization Consensus Committee published a histologic typing system for tumors of the thymus. METHODS: We reclassified a series of 100 thymomas resected at Tokushima University Hospital and four affiliated hospitals in Japan between 1973 and 2001 according to the World Health Organization histologic classification and reported its clinicopathologic relationship and prognostic relevance. RESULTS: There were 8 type A, 17 type AB, 27 type B1, 8 type B2, 12 type B3, and 28 type C thymomas. The frequency of invasion to neighboring organs increased according to tumor subtype in the order A (0%), AB (6%), B1 (19%), B2 (25%), B3 (42%), and C (89%). There was no recurrence in patients with type A, AB, or B2 thymoma. The recurrence rates of patients with B1, B3, or C thymoma were 15%, 36%, and 47%, respectively. The disease-free survival rates were 100% for types A and AB, 83% for types B1 and B2, 36% for type B3, and 28% for type C thymoma at 10 years. There were significant differences in disease-free survival between types A and AB and types B1 and B2 (p = 0.0436), and between type B3 and type C (p = 0.042). By multivariate analysis, only Masaoka clinical stage (p = 0.002) showed significant independent effects on disease-free survival. The 10-year survival rates of types A and AB, types B1 and B2, type B3, and type C thymoma were 100%, 94%, 92%, and 58%, respectively. CONCLUSIONS: The current study confirmed the World Health Organization histologic classification as a good prognostic factor.

Orthotopically implanted SCID mouse model of human lung cancer suitable for investigating metastatic potential and anticancer drug effects.

To evaluate the effects of drugs in clinical settings, an animal model of lung cancer similar to clinical cancer is necessary. Our previous studies described an SCID mouse model using orthotopic implantation of the human lung cancer cell line which mimicked the lymph node metastasis of patients with lung cancer. In this study, we made animal models that reflected various metastatic forms of lung cancer in humans. We applied our procedure to 6 lung cancer cell lines. Suspensions of 2.0 x 10(4) cancer cells were injected into the left lung of SCID mice. We evaluated the mRNA expressions of 52 proteins related to the metabolism of and resistance to anticancer drugs of each tumor cell line and its orthotopically implanted tumor using a customized cDNA array. Three lung cancer cell lines had the potential of lymphogenous metastasis and 3 cell lines had the potential of hematogenous metastasis in this model system. The A549 line showed multiple metastases, and Ma2 line showed solitary metastasis. The expression of 52 genes in each implanted tumor was closely correlated with that in each cell lines (correlation coefficients: 0.8883-0.9533), and the gradient of the regression line was more than 0.9. This model was similar to the metastatic form in patients with lung cancer. The similar expression of proteins in each tumor cell line in vitro and implanted tumor in vivo gives an advantage in evaluating the effects of molecular-targeted drugs and the relationship between specific genes and tumor potential in preclinical studies.

Establishment of patient-like SCID mouse model by orthotopically implanting primary cultured cells from surgically-resected lung cancer tissues.

In our previous studies, we established a lymphogenous metastatic SCID mouse model using orthotopic implantation of human lung cancer cell lines. However, the lymphogenous metastatic potential of each cell line in our models does not reflect that of a primary tumor. In this study, we made orthotopic implanted models using primary cultured cells from surgically-resected lung cancer tissues. Tissues of 5 patients with non-small cell lung cancer (NSCLC) were applied to a primary culture method using a collagen gel coated flask. Suspensions of 2.0x10(4) cancer cells were injected into the left lung of SCID mice. We could maintain primary culture cells from 2 (FM205 and FT821 cells) of 5 lung cancers, and made orthotopically implanted SCID mouse models. The size of both tumors in implanted sites of the lung increased with time. The FM205 cells microscopically were metastasized to the mediastinum by 4 weeks after implantation and macroscopically metastasized by 16 weeks. The FT821 cells were microscopically metastasized to the mediastinum by 4 weeks after implantation and macroscopically metastasized by 6 weeks. The lymphogenous metastatic potential of these primary culture cells was similar to that of clinical tumors. As the lymphogenous metastatic potential of this model reflects that of the clinical tumor, it is useful for elucidating the mechanism of lymphogenous metastasis and selecting anticancer drugs suitable for an individual patients.

Green fluorescent protein expression and visualization of mediastinal lymph node metastasis of human lung cancer cell line using orthotopic implantation.

BACKGROUND: Suppression of lymphatic metastasis improves survival in lung cancer patients. We have reported a patient-like model of lung cancer metastasis based on orthotopic implantation in severe combined immunodeficiency (SCID) mice and demonstrated the lymphogenous spread histologically using human NSCLC cell lines. MATERIALS AND METHODS: To visualize micrometastases, we transfected the Aequorea Victoria jellyfish green fluorescent protein (GFP) gene to the cancer cell line. RESULTS: The tumor cell lines were able to stably express GFP at high levels both in vitro and in vivo. Fluorescent tumors and metastasis of the mediastinum could be visualized at microscopic levels after transplantation. CONCLUSION: This model demonstrated that GFP gene-transfected tumor cells represent a new tool for evaluating the metastatic process and are very useful for developing chemotherapy to inhibit metastasis.

Effect of ursodeoxycholic acid on azoxymethane-induced aberrant crypt foci formation in rat colon: in vitro potential role of intracellular Ca2+.

The studies were conducted to examine the precise nature of the suppressive effect of ursodeoxycholic acid (UDCA) on colonic aberrant crypt foci (ACF) formation. Fischer 344 rats were treated with a single dose of azoxymethane (AOM) (20 mg/kg, s.c.) and fed basal diet (MF) supplemented with UDCA (0.4%) during an initiation or a post-initiation stage. ACF were enumerated at the 2nd, 5th and 8th weeks after AOM administration (15-18 rats/group). The number of ACF in the UDCA treated group was decreased significantly in the initiation and post-initiation stages at the 2nd (P < 0.01, P < 0.0001) and 8th weeks (P < 0.001, P < 0.0001), respectively, compared with untreated controls. In the time-course experiments, the effect of continuous feeding of UDCA (0.4%) on ACF formation was evaluated. ACF number was decreased significantly (P < 0.005) until the 16th week. UDCA showed a significant dose-dependent suppression of ACF number from a range of 0.1-0.4% UDCA. To approach the subcellular mechanisms of the effect of bile acids, the intracellular free Ca2+ concentration ([Ca2+]i) of bile acid-treated rat colonic cancer cells (ACL-15) was examined. DCA and CDCA, which are promotive on ACF formation, induced a rapid increase in [Ca2+]i, while UDCA and CA, which are suppressive or non-effective on ACF formation, did not. These findings suggest that the promotive effect of bile acids may involve intracellular Ca2+ signaling.

Novel bronchofiberscopic catheter spray device allows effective anesthetic spray and sputum suctioning.

STUDY OBJECTIVES: To evaluate how serum lidocaine concentrations (SLC) rise when lidocaine is administered by a Bronchofiberscopic Catheter Spray Device (BCSD), and to demonstrate the effect on the aspiration speed of a substitute for sputum when a catheter spray remains in the channel of the bronchofiberscope (BF). METHODS: This is a prospective randomized clinical study. After lidocaine ultrasonic nebulizer, the BF was inserted orally. During the procedure patients received 4% lidocaine by two methods. In Group 1, 11 patients received lidocaine by bronchofiberscopic (BF) injection. In Group 2, 15 patients received lidocaine by spraying from the diameter 1.06 mm catheter through the BF channel. SLC were measured at 40 min from onset of nebulization. Separately, we examined how effectively sputum was aspirated through the BF channel with a catheter. RESULTS: Total lidocaine dose (TLD) is the total dose used for nebulization and for the BF injection or spray. The TLD for Groups 1 and 2 were 698.2+/-162.1 mg (mean+/-SD) and 498.7+/-103.8 mg, respectively (P = 0.03). The SLC for Groups 1 and 2 were 1.28+/-0.72 and 1.48+/-0.70 mg/l, respectively (P = 0.49). CONCLUSIONS: Using BCSD allows easier in administration of lidocaine and is not associated with a significant increase in SLC in comparison with BF injection. Although sputum aspiration using the BF inserted with our catheter was somewhat slow, we did not feel inconvenient so much. Compared to the conventional method, using BCSD may be preferable for patients and bronchoscopists.

[Therapy for multiple primary lung cancers].

We considered 33 patients to have a multiple primary lung cancer (MPLC) at our hospital from January 1986 to August 2001. We used the criteria of Martini and Melamed for MPLC. Sixteen patients developed metachronous cancer within 0.8 to 9.4 years of the first operation (mean 4.2 years), while 17 patients had synchronous cancers. The most common histologic pair was squamous cell carcinoma-squamous cell carcinoma (45%). The next was adenocarcinoma-adenocarcinoma (21%). Stage I lesions occupied 80% of all lesions. Nine patients underwent lobectomy, while 9 patients underwent surgery including a limited operation. Eleven patients had non-surgical local treatment including photodynamic therapy (PDT), brachytherapy, and radiation therapy. Five-year survival for patients with synchronous and metachronous disease from second operation was 36.1% and 40.1%, respectively. Survival of patients including only stage I non-small cell lung cancer (NSCLC) lesions was significantly better compared with those including stage II or III NSCLC and SCLC lesions (p = 0.002). Therefore it is very important to perform close follow-up surveillance for early detection of cancer.

Serum adiponectin level is correlated with the size of HDL and LDL particles determined by high performance liquid chromatography.

OBJECTIVE: Adiponectin (APN) improves insulin resistance and prevents atherosclerosis, and HDL removes cholesterol from atherosclerotic lesions. We have demonstrated that serum HDL-cholesterol (HDL-C) and APN concentrations are positively correlated and that APN accelerates reverse cholesterol transport (RCT) by increasing HDL synthesis in the liver and cholesterol efflux from macrophages. We previously reported that APN reduced apolipoprotein (apo) B secretion from the liver. It is well-known that insulin resistance influences the lipoprotein profile. In this study, we investigated the clinical significance of APN levels and insulin resistance in lipoprotein metabolism. MATERIAL/METHOD: We investigated the correlation between serum APN concentration, HOMA-R, the lipid concentrations and lipoprotein particle size by high-performance liquid chromatography (HPLC) in 245 Japanese men during an annual health checkup. RESULTS: Serum APN level was positively correlated with the cholesterol content in large LDL and HDL particles, but inversely correlated with the cholesterol content in large VLDL and small LDL particles. HOMA-R was negatively correlated with the cholesterol content in large LDL and HDL particles and positively correlated with the cholesterol content in large VLDL and small LDL particles. By multivariate analysis, APN was correlated with the particle size of LDL-C and HDL-C independently of age, BMI and HOMA-R. CONCLUSIONS: APN may be associated with the formation of both HDL and LDL particles, reflecting the enhancement of RCT and the improvement in TG-rich lipoprotein metabolism and insulin resistance.

Serum apolipoprotein B-48 levels are correlated with carotid intima-media thickness in subjects with normal serum triglyceride levels.

BACKGROUND: Postprandial hyperlipidemia (PPHL) is an independent risk factor for coronary heart disease (CHD) which is based on the accumulation of chylomicrons (CM) and CM remnants containing apolipoprotein B-48 (apoB-48). Since atherosclerotic cardiovascular diseases are frequently observed even in subjects with normal serum triglyceride (TG) level, the correlation between fasting apoB-48 containing lipoproteins and carotid intima-media thickness (IMT) was analyzed in subjects with normal TG levels. METHODS: From subjects who took their annual health check at the Osaka Police Hospital (n=245, male), one-hundred and sixty-four male subjects were selected to take part in this study; the excluding factors were: systolic blood pressure ≥ 140 mmHg, intake of antihypertensive or antihyperlipidemic drugs, or age >65 years. The association between biochemical markers and IMT was analyzed and independent predictors of max-IMT were determined by multiple regression analysis in all subjects and in groups N-1 (TG<100mg/dl, n=58), N-2 (100 ≤ TG<150 mg/dl, n=53) and H (150 ≤ TG mg/dl, n=53), respectively. RESULTS: Fasting total cholesterol, LDL-cholesterol, HDL-cholesterol, apoB-100 and lnRemL-C (remnant lipoprotein-cholesterol) levels were not correlated with max-IMT, but lnTG and lnapoB-48 were significantly correlated with max-IMT in all subjects. LnapoB-48 and apoB-48/TG ratio were significantly correlated with max-IMT in group N-2. By multiple regression analysis, age and lnapoB-48 were independent variables associated with max-IMT in group N-2. CONCLUSION: Serum apoB-48 level might be a good marker for the detection of early atherosclerosis in middle-aged subjects with normal-range levels of blood pressure and TG.