长期应用核苷类逆转录酶抑制剂对HIV/AIDS患者脂肪代谢的影响

 目的 探讨长期应用含核苷类逆转录酶抑制剂（NRTIs）的高效抗逆转录病毒治疗（HAART）对HIV/AIDS患者脂肪代谢的影响及相关因素。方法 招募118例HIV/AIDS患者,其中未治疗组40例,治疗1~2年组37例,治疗>5年组41例,以20名健康志愿者作为对照组。临床评估是否存在脂肪代谢障碍（LD）。经双能X线骨密度吸收仪（DXA）测量全身、躯干、上肢及下肢脂肪量（FM）。结果 治疗>5年组与治疗1~2年组患者临床评估LD发生率分别为51.2%和40.5%,组间比较差异无统计学意义。应用司他夫定（d4T）出现LD发生率（63.6%）为应用齐多夫定（AZT）者（26.5%）的2.4倍,差异有统计学意义（P=0.001）。DXA检测显示：治疗>5年组患者全身及四肢FM［(9778±3758) g和上肢（960±449）g,下肢（2096±1141）g］均显著低于健康对照组［（13 317±5825） g和上肢（2333±1422） g,下肢（3890±1567） g］、未治疗组［（14 280±6416） g和上肢（1655±1251） g,下肢（4032±1822）g］及治疗1~2年组［（13 750±5910） g和上肢（1220±634） g,下肢（3276±1890） g］（P5年组中无LD患者,其全身及躯干FM亦显著低于治疗1~2年组无LD患者（P5年组患者LD发生率差异无统计学意义,但FM随HAART时间延长逐渐减低。DXA有助于客观定量评估FM变化,能早期发现LD并指导临床治疗。     

Fetal mitochondrial heart and skeletal muscle damage in Erythrocebus patas monkeys exposed in utero to 3'-azido-3'-deoxythymidine

3'-azido-3'-deoxythymidine (AZT) is given to pregnant women positive for the human immunodeficiency virus type 1 (HIV-1) to reduce maternal-fetal viral transmission. To explore fetal mitochondrial consequences of this exposure, pregnant Erythrocebus patas monkeys were given daily doses of 1.5 mg (21% of the human daily dose) and 6.0 mg (86% of the human daily dose) of AZT/kg body weight (bw), for the second half of gestation. At term, electron microscopy of fetal cardiac and skeletal muscle showed abnormal and disrupted sarcomeres with myofibrillar loss. Some abnormally shaped mitochondria with disrupted cristae were observed in skeletal muscle myocytes. Oxidative phosphorylation (OXPHOS) enzyme assays showed dose-dependent alterations. At the human-equivalent dose of AZT (6 mg of AZT/kg bw), there was an approximately 85% decrease in the specific activity of NADH dehydrogenase (complex I) and three- to sixfold increases in specific activities of succinate dehydrogenase (complex II) and cytochrome-c oxidase (complex IV). Furthermore, a dose-dependent depletion of mitochondrial DNA levels was observed in both tissues. The data demonstrate that transplacental AZT exposure causes cardiac and skeletal muscle mitochondrial myopathy in the patas monkey fetus.     

Expression of ICAM-1, ICAM-2, NCAM-1 and VCAM-1 by human synovial cells exposed to Borrelia burgdorferi in vitro

The interaction of resident tissue cells with migratory inflammatory cells is essential for the recruitment of immune effector cells to inflammatory sites. The sustained expression of adhesion molecules in the synovium of patients with chronic Lyme arthritis seems to contribute to this chronic inflammation. Whether cell adhesion molecules influence the early steps of Borreliosis is unclear. Therefore, we examined the expression of ICAM-1, ICAM-2, VCAM-1 and NCAM-1 in synovial cells exposed to two different Borrelia burgdorferi sensu stricto strains Geho and B31. The mRNA expression of ICAM-1, ICAM-2, VCAM-1 and NCAM-1 was not changed in synovial cells exposed to B31. Whereas ICAM-2 and VCAM-1 was upregulated, NCAM-1 mRNA was downregulated and ICAM-1 mRNA was unchanged by strain Geho. The ICAM-1 protein expression on the synovial cell surface was downregulated by both strains. Differential regulation of adhesion molecule mRNA, and subsequent high turnover or elevated shedding from the cell membrane may contribute to early pathogenesis in Lyme arthritis.     

Epoxyeicosatrienoic acids limit damage to mitochondrial function following stress in cardiac cells

Epoxyeicosatrienoic acids (EETs) are polyunsaturated fatty acids synthesized from arachidonic acid by CYP2J2 epoxygenase and inactivated by soluble epoxide hydrolase (sEH or Ephx2) to dihydroxyeicosatrienoic acids. Mitochondrial function following ischemic insult is a critical determinant of reperfusion-induced cell death in the myocardium. The objectives of the current study were to investigate the protective role of EETs in mitochondrial function. Mice with the targeted disruption of the Ephx2 gene, cardiomyocyte-specific overexpression of CYP2J2 or perfused with EETs all have improved postischemic LVDP recovery compared to wild-type (WT). Perfusion with the mPTP opener, atractyloside, abolished the improved postischemic functional recovery observed in CYP2J2 Tr, sEH null and EET perfused hearts. Electron micrographs demonstrated WT hearts to have increased mitochondrial fragmentation and T-tubule swelling compared to CYP2J2 Tr hearts following 20 min global ischemia and 20 min reperfusion. Direct effects of EETs on mitochondria were assessed in isolated rat cardiomyocytes and H9c2 cells. Laser-induced loss of mitochondrial membrane potential (ΔΨ_m) and mPTP opening was significantly reduced in cells treated with 14, 15-EET (1 μM). The EET protective effect was blocked by the putative EET antagonist 14,15-epoxyeicosa-5(Z)-enoic acid (1 μM, 14, 15-EEZE), paxilline (10 μM, BK_Ca inhibitor) and 5HD (100 μM, K_ATP inhibitor). Our studies show that EETs can limit mitochondrial dysfunction following cellular stress via a K⁺ channel-dependent mechanism.     

Effect of ENPP1/PC-1-K121Q and PPARgamma-Pro12Ala polymorphisms on the genetic susceptibility to T2D in the Tunisian population

Diabetes mellitus is the most common chronic metabolic disease. The raising diabetes epidemic is unfolding as an interaction between several environmental factors and a genetic predisposition. The aim of the current study was to evaluate the role of the PPARγ-Pro12Ala and ENPP1-K121Q polymorphisms on type 2 diabetes (T2D) risk in a case–control study in the Tunisian population. To assess for any association of ENPP1-K121Q and PPARγ-Pro12Ala polymorphisms with T2D risk, we analysed the genotypic and allelic distributions of each variant in the studied cohort. Our results support that the genetic variation at ENPP1-K121Q predisposes to T2D in the Tunisian population after adjustment on gender, age and BMI status (OR = 1.55, 95%CI [1.11–2.16], p = 0.007).Conversely, the PPARγ-Pro12Ala variant seems not to have a significant effect on T2D risk in our Tunisian cohort. However, the minor A-allele would convey protection against overweight in the Tunisian population. In fact, the over weighted subjects showed a significantly lower frequency of A-allele than lean controls (OR = 0.49, 95%CI [0.25–0.97], p = 0.02). In conclusion, our findings support the hypothesis that ENPP1-121Q is involved in the genetic susceptibility of T2D in the Tunisian population, while the PPARγ-12Ala allele may confer protection against overweight.     

Genetic polymorphism in pvmdr1 and pvcrt-o genes in relation to in vitro drug susceptibility of Plasmodium vivax isolates from malaria-endemic countries

Treatment failure of chloroquine for Plasmodium vivax infection has increased in endemic countries. However, the molecular mechanisms for resistance and in vitro susceptibility of P. vivax to chloroquine remain elusive. We investigated the prevalence of mutations in the pvmdr1 and pvcrt-o genes, and the copy number of the pvmdr1 gene in isolates from the Republic of Korea (ROK), Thailand, the Union of Myanmar (Myanmar), and Papua New Guinea (PNG). We also measured in vitro susceptibility of Korean isolates to antimalarial drugs. The pvmdr1 analysis showed that mutations at amino acid position Y976F of pvmdr1 were found in isolates from Thailand (17.9%), Myanmar (13.3%), and PNG (100%), but none from the ROK, and mutation at position F1076L was present in isolates from the ROK (100%), Thailand (60.7%), and Myanmar (46.7%). One copy of the pvmdr1 gene was observed in most isolates and double copy numbers of the gene were observed in two Thai isolates. In the exons of the pvcrt-o gene that were sequenced, a K10 insertion was present in isolates from Thailand (56.0%) and Myanmar (46.2%), and the wild type was found in all Korean isolates. The results suggest that gene polymorphisms and copy number variation was observed in isolates of P. vivax from Southeast Asian countries. In Korean isolates polymorphism as limited to the F1076L variant, and no isolates with high level of resistance were found by in vitro susceptibility determinations. Moreover, our results provide a baseline for future prospective drug studies in malaria-endemic areas.     

Involvement of VEGFR-2 (kdr/flk-1) but not VEGFR-1 (flt-1) in VEGF-A and VEGF-C-induced tube formation by human microvascular endothelial cells in fibrin matrices in vitro

Different forms of vascular endothelial growth factor (VEGF) and their cellular receptors (VEGFR) are associated with angiogenesis, as demonstrated by the lethality of VEGF-A, VEGFR-1 or VEGFR-2 knockout mice. Here we have used an in vitro angiogenesis model, consisting of human microvascular endothelial cells (hMVEC) cultured on three-dimensional (3D) fibrin matrices to investigate the roles of VEGFR-1 and VEGFR-2 in the process of VEGF-A and VEGF-C-induced tube formation. Soluble VEGFR-1 completely inhibited the tube formation induced by the combination of VEGF-A and TNFα (VEGF-A/TNFα). This inhibition was not observed when tube formation was induced by VEGF-C/TNFα or bFGF/TNFα. Blocking monoclonal antibodies specific for VEGFR-2, but not antibodies specifically blocking VEGFR-1, were able to inhibit the VEGF-A/TNFα-induced as well as the VEGF-C/TNFα-induced tube formation in vitro. PlGF-2, which interacts only with VEGFR-1, neither induced tube formation in combination with TNFα, nor inhibited or stimulated by itself the VEGF-A/TNFα-induced tube formation in vitro. These data indicate that VEGF-A or VEGF-C activation of the VEGFR-2, and not of VEGFR-1, is involved in the formation of capillary-like tubular structures of hMVEC in 3D fibrin matrices used as a model of repair-associated or pathological angiogenesis in vitro. This revised version was published online in June 2006 with corrections to the Cover Date.     

Gene expression of interstitial collagenase (matrix metalloproteinase 1) in gastrointestinal tract cancers

Collagenolytic proteinases play an important pathological role in the invasion and metastasis of cancer cells. However, little is known about the role of interstitial collagenase (matrix metalloproteinase-1; MMP-1) in this process. To investigate the expression of the MMP-1 gene in cancer tissues, anin situ hybridization study was carried out in gastrointestinal tract cancers (one esophageal cancer, five gastric cancers, and four colorectal cancers), using a³⁵S-labeled MMP-1 cDNA probe. The MMP-1 gene was expressed in the stromal cells of fibrous tissue around cancer nests, especially at the margin of invasion and/or within the cancer nest; however, no definite expression within cancer cells was observed. Expression of the MMP-1 gene in the stromal cells was more common in well differentiated gastric adenocarcinoma than in poorly differentiated adenocarcinomas. These findings indicate that expression of the MMP-1 gene is greater in stromal cells that are closely associated with cancer cells, suggesting a pathophysiological role of MMP-1 in the invasion and metastasis of cancer cells.