Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 16 de 16
Filtrar
1.
PLoS One ; 13(1): e0189869, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29364895

RESUMO

INTRODUCTION: Attempts to conceive and pregnancy may increase HIV transmission to sex partners and infants. Our study evaluated the association between fertility intentions and HIV acquisition among Zambian HIV-serodiscordant couples. METHODS: We collected demographic, behavioral, clinical exposures, and data on fertility intentions in a cohort of HIV-serodiscordant couples in Lusaka, Zambia from 2005 to 2012. We evaluated factors associated with fertility intentions stratified by gender using multivariable logistic regression. Multivariable Cox proportional hazard models were used to evaluate the associations between fertility intentions and HIV acquisition controlling for a priori confounders and covariates that substantially (>10%) changed the effect estimates in univariate analyses. RESULTS: Among 1,029 serodiscordant couples, 311 agreed that they wanted children in the future (30%), 368 agreed they did not want children (36%), and 344 couples disagreed about having children (34%), with men more likely than women to want children. Women wanting child(ren) was associated with increased odds of baseline pregnancy (adjusted odds ratio [aOR] = 4.80 (95% confidence interval [CI] = 2.93, 7.85)), fewer previous pregnancies (aOR = 0.85 per additional pregnancy (95% CI = 0.78, 0.93)), and partner fertility intention (aOR = 2.89 (95% CI = 2.14, 3.91)) adjusting for woman's age, literacy, years cohabiting and HIV status. Men wanting child(ren) was associated with younger age (aOR = 0.96 per year (95% CI = 0.93, 0.99)), fewer years cohabiting (aOR = 0.95 (95% CI = 0.92, 0.98)), number of previous partners' pregnancies (aOR = 0.90 (95% CI = 0.82, 0.98)), and partner fertility intention (aOR = 3.00 (95% CI = 2.21, 4.07)) adjusting for partner's age, literacy, HIV status and partner's baseline pregnancy. In adjusted survival analyses, HIV-negative women were more likely to seroconvert if they themselves wanted children (aHR = 2.36 (95% CI = 1.41, 3.96)) vs. did not want children, or if their partner wanted children (aHR = 2.34 (95% CI = 1.33, 4.11)) vs. did not want children, or if the couple agreed that they wanted children (aHR = 2.08 (95% CI = 1.01, 4.30)), adjusting for women's age, women's literacy, previous pregnancies and time in study. HIV-negative men were more likely to seroconvert if their female partner wanted a child in the next 12-months (aHR = 1.94 (95% CI = 1.02, 3.68)) vs. did not want children, and when both partners wanted children (aHR = 2.02 (CI = 1.09, 3.73)) vs. they did not want children, adjusting for men's age and literacy, couple income, number of live children, male circumcision status and time in study. CONCLUSION: Women had increased risk of HIV acquisition if they and/or their partner wanted a child, while men had increased risk of HIV acquisition when their partner or if both partners agreed that they wanted children. Safer-conception interventions are needed to protect HIV uninfected women and men from HIV acquisition in HIV-serodiscordant couples who want children.


Assuntos
Tomada de Decisões , Serviços de Planejamento Familiar , Infecções por HIV/fisiopatologia , Infecções por HIV/transmissão , Parceiros Sexuais , Adulto , Feminino , Humanos , Masculino , Estudos Prospectivos , Adulto Jovem , Zâmbia
2.
AIDS Behav ; 22(7): 2386, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-28956345

RESUMO

The article Risky Sex and HIV Acquisition Among HIV Serodiscordant Couples in Zambia, 2002-2012: What Does Alcohol Have To Do With It?, written by Dvora Joseph Davey, William Kilembe, Kristin M. Wall, Naw Htee Khu, Ilene Brill, Bellington Vwalika, Elwyn Chomba, Joseph Mulenga, Amanda Tichacek, Marjan Javanbakht, W. Scott Comulada, Susan Allen, Pamina M. Gorbach, was originally published Online First without open access. After publication in volume 21, issue 7, pages 1892-1903, the author decided to opt for Open Choice and to make the article an open access publication. Therefore, the copyright of the article has been changed to

3.
J Womens Health (Larchmt) ; 26(8): 900-910, 2017 08.
Artigo em Inglês | MEDLINE | ID: mdl-28829720

RESUMO

BACKGROUND: Dual method use, which combines condoms with a more effective modern contraceptive to optimize prevention of HIV and unplanned pregnancy, is underutilized in high-risk heterosexual couples. MATERIALS AND METHODS: Heterosexual HIV-discordant Zambian couples were enrolled from couples' voluntary HIV counseling and testing services into an open cohort with 3-monthly follow-up (1994-2012). Relative to dual method use, defined as consistent condom use plus modern contraception, we examine predictors of (1) condom-only use (suboptimal pregnancy prevention) or (2) modern contraceptive use with inconsistent condom use (effective pregnancy prevention and suboptimal HIV prevention). RESULTS: Among 3,049 couples, dual method use occurred in 28% of intervals in M+F- and 23% in M-F+, p < 0.01; condom-only use in 56% in M+F- and 61% in M-F+, p < 0.01; and modern contraceptive use with inconsistent condom use in 16% regardless of serostatus. Predictors (p < 0.05) of condom-only use included the man being HIV+ (adjusted hazard ratio, aHR = 1.15); baseline oral contraceptive pill (aHR = 0.76), injectable (aHR = 0.48), or implant (aHR = 0.60) use; woman's age (aHR = 1.04 per 5 years) and lifetime number of sex partners (aHR = 1.01); postpartum periods (aHR = 1.25); and HIV stage of the index partner III/IV versus I (aHR = 1.10). Predictors (p < 0.05) of modern contraceptive use with inconsistent condom use included woman's age (aHR = 0.94 per 5 years) and HIV+ male circumcision (aHR = 1.51), while time-varying implant use was associated with more consistent condom use (aHR = 0.80). CONCLUSIONS: Three-quarters of follow-up intervals did not include dual method use. This highlights the need for counseling to reduce unintended pregnancy and HIV transmission and enable safer conception.


Assuntos
Preservativos/estatística & dados numéricos , Comportamento Contraceptivo/estatística & dados numéricos , Anticoncepção/métodos , Anticoncepção/estatística & dados numéricos , Infecções por HIV/prevenção & controle , Soronegatividade para HIV , Soropositividade para HIV , Gravidez não Planejada , Adulto , Estudos de Coortes , Aconselhamento , Características da Família , Feminino , Humanos , Masculino , Gravidez , Parceiros Sexuais , Zâmbia
4.
AIDS Behav ; 21(7): 1892-1903, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-28243934

RESUMO

In this paper we evaluate the effects of heavy alcohol consumption on sexual behavior, HIV acquisition, and antiretroviral treatment (ART) initiation in a longitudinal open cohort of 1929 serodiscordant couples in Lusaka, Zambia from 2002 to 2012. We evaluated factors associated with baseline heavy alcohol consumption and its association with condomless sex with the study partner, sex outside of the partnership, and ART initiation using multivariable logistic regression. We estimated the effect of alcohol consumption on HIV acquisition using multivariable Cox models. Baseline factors significantly associated with women's heavy drinking (drunk weekly or more in 12-months before enrollment) included woman's older age (adjusted prevalence odds ratio [aPOR] = 1.04), partner heavy drinking (aPOR = 3.93), and being HIV-infected (aPOR = 2.03). Heavy drinking among men was associated with less age disparity with partner (aPOR per year disparity = 0.97) and partner heavy drinking (aPOR = 1.63). Men's being drunk daily (aOR = 1.18), women's being drunk less than monthly (aOR = 1.39) vs. never drunk and being in a male HIV-negative and female HIV-positive union (aOR = 1.45) were associated with condomless sex. Heavy alcohol use was associated with having 1 or more outside sex partners among men (aOR drunk daily = 1.91, drunk weekly = 1.32, drunk monthly = 2.03 vs. never), and women (aOR drunk monthly = 2.75 vs. never). Being drunk weekly or more increased men's risk of HIV acquisition (adjusted hazard ratio [aHR] = 1.72). Men and women being drunk weekly or more was associated (p < 0.1) with women's seroconversion (aHR = 1.42 and aHR = 3.71 respectively). HIV-positive women who were drunk monthly or more had lower odds of initiating ART (aOR = 0.83; 95% CI = 0.70-0.99) adjusting for age, months since baseline and previous pregnancies. Individuals in HIV-serodiscordant couples who reported heavy drinking had more outside sex partnerships and condomless sex with their study partner and were more likely to acquire HIV. HIV-positive women had lower odds of initiating ART if they were heavy drinkers.


Assuntos
Consumo de Bebidas Alcoólicas/epidemiologia , Intoxicação Alcoólica/epidemiologia , Infecções por HIV/transmissão , Sexo sem Proteção/estatística & dados numéricos , Adulto , Fatores Etários , Estudos de Coortes , Feminino , Humanos , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Razão de Chances , Prevalência , Modelos de Riscos Proporcionais , Fatores de Risco , Comportamento Sexual/estatística & dados numéricos , Parceiros Sexuais , Adulto Jovem , Zâmbia/epidemiologia
6.
BMC Med ; 14(1): 171, 2016 10 27.
Artigo em Inglês | MEDLINE | ID: mdl-27784313

RESUMO

BACKGROUND: In 2012, the World Health Organization recommended the addition of single low-dose primaquine (SLDPQ, 0.25 mg base/kg body weight) to artemisinin combination therapies to block the transmission of Plasmodium falciparum without testing for glucose-6-phosphate dehydrogenase deficiency. The targeted group was non-pregnant patients aged ≥ 1 year (later changed to ≥ 6 months) with acute uncomplicated falciparum malaria, primarily in countries with artemisinin-resistant P. falciparum (ARPf). No dosing regimen was suggested, leaving malaria control programmes and clinicians in limbo. Therefore, we designed a user-friendly, age-based SLDPQ regimen for Cambodia, the country most affected by ARPf. METHODS: By reviewing primaquine's pharmacology, we defined a therapeutic dose range of 0.15-0.38 mg base/kg (9-22.5 mg in a 60-kg adult) for a therapeutic index of 2.5. Primaquine doses (1-20 mg) were tested using a modelled, anthropometric database of 28,138 Cambodian individuals (22,772 healthy, 4119 with malaria and 1247 with other infections); age distributions were: 0.5-4 years (20.0 %, n = 5640), 5-12 years (9.1 %, n = 2559), 13-17 years (9.1 %, n = 2550), and ≥ 18 years (61.8 %, n = 17,389). Optimal age-dosing groups were selected according to calculated mg base/kg doses and proportions of individuals receiving a therapeutic dose. RESULTS: Four age-dosing bands were defined: (1) 0.5-4 years, (2) 5-9 years, (3) 10-14 years, and (4) ≥15 years to receive 2.5, 5, 7.5, and 15 mg of primaquine base, resulting in therapeutic doses in 97.4 % (5494/5640), 90.5 % (1511/1669), 97.7 % (1473/1508), and 95.7 % (18,489/19,321) of individuals, respectively. Corresponding median (1st-99th centiles) mg base/kg doses of primaquine were (1) 0.23 (0.15-0.38), (2) 0.29 (0.18-0.45), (3) 0.27 (0.15-0.39), and (4) 0.29 (0.20-0.42). CONCLUSIONS: This age-based SLDPQ regimen could contribute substantially to malaria elimination and requires urgent evaluation in Cambodia and other countries with similar anthropometric characteristics. It guides primaquine manufacturers on suitable tablet strengths and doses for paediatric-friendly formulations. Development of similar age-based dosing recommendations for Africa is needed.


Assuntos
Antimaláricos/administração & dosagem , Malária Falciparum/tratamento farmacológico , Primaquina/administração & dosagem , Adolescente , Adulto , Fatores Etários , Camboja , Transmissão de Doença Infecciosa/prevenção & controle , Quimioterapia Combinada , Feminino , Deficiência de Glucosefosfato Desidrogenase/metabolismo , Deficiência de Glucosefosfato Desidrogenase/parasitologia , Humanos , Malária Falciparum/enzimologia , Malária Falciparum/prevenção & controle , Malária Falciparum/terapia , Masculino , Pessoa de Meia-Idade , Adulto Jovem
7.
J Infect Dis ; 214(7): 1063-71, 2016 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-27462093

RESUMO

BACKGROUND: Evidence on the association between female-to-male human immunodeficiency virus (HIV) transmission risk and hormonal contraception is sparse and conflicting. METHODS: Heterosexual HIV-discordant couples from Lusaka, Zambia, were followed longitudinally at 3 month-intervals from 1994 to 2012. The impact of hormonal contraception on time to HIV transmission from HIV-positive women to their HIV-negative male partners (M-F+) was evaluated. RESULTS: Among 1601 M-F+ couples, 171 genetically linked HIV transmissions occurred in men over 3216 couple-years (5.3 transmissions/100 couple-years; 95% confidence interval [CI], 4.5-6.2). In multivariable Cox models, neither injectable (adjusted hazard ratio [aHR], 0.6; 95% CI, .4-1.2), oral contraceptive pill (aHR, 0.8; 95% CI, .3-2.1), nor implant (aHR, 0.8; 95% CI, .5-1.4) use was associated with HIV transmission, relative to nonhormonal methods, after controlling for the man's age at baseline and time-varying measures of pregnancy, self-reported unprotected sex with the study partner, sperm present on a vaginal swab wet mount, genital inflammation of either partner, genital ulceration of the man, and first follow-up interval. Sensitivity analyses, including marginal structural modeling and controlling for viral load and fertility intentions available in a subset of couples, led to similar conclusions. CONCLUSIONS: Our findings suggest null associations between hormonal contraception and risk of female-to-male HIV transmission. We support efforts to increase the contraceptive method mix for all women, regardless of HIV serostatus, along with reinforced condom counseling for HIV-serodiscordant couples.


Assuntos
Anticoncepcionais Orais Hormonais/administração & dosagem , Transmissão de Doença Infecciosa , Uso de Medicamentos , Infecções por HIV/transmissão , Adulto , Feminino , Humanos , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Gravidez , Medição de Risco , Zâmbia
8.
J Acquir Immune Defic Syndr ; 71(3): 345-52, 2016 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-26379070

RESUMO

BACKGROUND: Some studies suggest that hormonal contraception, pregnancy, and/or breastfeeding may influence rates of HIV disease progression. METHODS: From 1994 to 2012, HIV discordant couples recruited at couples' voluntary HIV counseling and testing centers in Lusaka were followed 3-monthly. Multivariate survival analyses explored associations between time-varying contraception, pregnancy, and breastfeeding and 2 outcomes among HIV-positive women: (1) time to death and (2) time to antiretroviral treatment (ART) initiation. RESULTS: Among 1656 female seropositive, male seronegative couples followed for 3359 person-years (PY), 224 women died [6.7/100 PY; 95% confidence interval (CI): 5.8 to 7.6]. After 2003, 290 women initiated ART (14.5/100 PY; 95% CI: 12.9 to 16.2). In a multivariate model of time to death, hormonal implant [adjusted hazard ratio (aHR) = 0.30; 95% CI: 0.10 to 0.98] and injectable (aHR = 0.59; 95% CI: 0.36 to 0.97) were significantly protective relative to nonhormonal method use, whereas oral contraceptive pill (OCP) use was not (aHR = 1.08; 95% CI: 0.74 to 1.57) controlling for baseline HIV disease stage, time-varying pregnancy, time-varying breastfeeding, and year of enrollment. In a multivariate model of time-to-ART initiation, implant was significantly protective (aHR = 0.54; 95% CI: 0.31 to 0.95), whereas OCP (aHR = 0.70; 95% CI: 0.44 to 1.10) and injectable (aHR = 0.85; 95% CI: 0.55 to 1.32) were not relative to nonhormonal method use controlling for variables above, woman's age, and literacy. Pregnancy was not significantly associated with death (aHR = 1.07; 95% CI: 0.68 to 1.66) or ART initiation (aHR = 1.24; 95% CI: 0.83 to 1.86), whereas breastfeeding was protective for death (aHR = 0.34; 95% CI: 0.19 to 0.62) and ART initiation (aHR = 0.49; 95% CI: 0.29 to 0.85). CONCLUSIONS: Hormonal implants and injectables significantly predicted lower mortality; implants were protective for ART initiation. OCPs and pregnancy were not associated with death or ART initiation, whereas breastfeeding was protective for both. Findings from this 18-year cohort study suggest that (1) HIV-positive women desiring pregnancy can be counseled to do so and breastfeed and (2) all effective contraceptive methods, including injectables and implants, should be promoted to prevent unintended pregnancy.


Assuntos
Fármacos Anti-HIV/uso terapêutico , Aleitamento Materno , Anticoncepcionais Femininos/farmacologia , Infecções por HIV/patologia , Adulto , Estudos de Coortes , Progressão da Doença , Implantes de Medicamento , Feminino , Infecções por HIV/tratamento farmacológico , Infecções por HIV/epidemiologia , Humanos , Masculino , Análise Multivariada , Gravidez , Modelos de Riscos Proporcionais , Fatores de Risco , Zâmbia/epidemiologia
9.
J Acquir Immune Defic Syndr ; 66(1): e1-7, 2014 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-24326600

RESUMO

INTRODUCTION: We describe predictors of first follow-up testing for concordant negative and discordant couples seeking joint voluntary HIV counseling and testing in Ndola, Zambia, where cohabiting couples account for an estimated two-thirds of incident HIV infections. METHODS: Demographic and serostatus data were collected from couples' voluntary HIV testing and counseling and follow-up testing services implemented in government clinics. We calculated follow-up testing rates by serostatus and compared rates before and after the introduction of a Good Health Package (GHP). RESULTS: The follow-up testing rate from May 2011 to December 2012 was 12.2% for concordant negative (M-F-) couples and 24.5% for discordant (M+F- or M-F+) couples. Significant predictors of follow-up testing in multivariate analyses included increasing age of the man [adjusted odds ratio (aOR) = 1.02 per year] and the woman (aOR = 1.02 per year), and either partner being HIV+ (aOR = 2.57 for HIV+ man, aOR = 1.89 for HIV+ woman). The man (aOR = 1.29) and the couple (aOR = 1.22) having been previously tested for HIV were predictive of follow-up testing among concordant negative couples. Introduction of a GHP increased follow-up testing among discordant (aOR = 2.93) and concordant negative (aOR = 2.06) couples. CONCLUSIONS: A low-cost GHP, including prevention, screening, and treatment for common causes of morbidity and mortality resulted in increased follow-up testing rates among HIV discordant and concordant negative couples. Overall follow-up testing rates remain low, and efforts to increase these rates are necessary to ensure linkage to combination prevention, reduce HIV transmission within couples, and identify seroconversions promptly. Further investigation of low-cost sustainable incentives and other factors influencing follow-up HIV testing for couples is needed.


Assuntos
Aconselhamento , Infecções por HIV/diagnóstico , Aceitação pelo Paciente de Cuidados de Saúde , Adolescente , Adulto , Aconselhamento/estatística & dados numéricos , Características da Família , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Aceitação pelo Paciente de Cuidados de Saúde/estatística & dados numéricos , Parceiros Sexuais , Adulto Jovem , Zâmbia
10.
AIDS ; 27 Suppl 1: S93-103, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-24088689

RESUMO

OBJECTIVE: To describe predictors of contraceptive method discontinuation and switching behaviours among HIV-positive couples receiving couples' voluntary HIV counselling and testing services in Lusaka, Zambia. DESIGN: Couples were randomized in a factorial design to two-family planning educational intervention videos, received comprehensive family planning services and were assessed every 3 months for contraceptive initiation, discontinuation and switching. METHODS: We modelled factors associated with contraceptive method upgrading and downgrading via multivariate Andersen-Gill models. RESULTS: Most women continued the initial method selected after randomization. The highest rates of discontinuation/switching were observed for injectable contraceptive and intrauterine device users. Time to discontinuing the more effective contraceptive methods or downgrading to oral contraceptives or condoms was associated with the women's younger age, desire for more children within the next year, heavy menstrual bleeding, bleeding between periods and cystitis/dysuria. Health concerns among women about contraceptive implants and male partners not wanting more children were associated with upgrading from oral contraceptives or condoms. HIV status of the woman or the couple was not predictive of switching or stopping. CONCLUSION: We found complicated patterns of contraceptive use. The predictors of contraception switching indicate that interventions targeted to younger couples that address common contraception-related misconceptions could improve effective family planning utilization. We recommend these findings be used to increase the uptake and continuation of contraception, especially long-acting reversible contraceptive (LARC) methods, and that fertility goal based, LARC-focused family planning be offered as an integral part of HIV prevention services.


Assuntos
Anticoncepção/métodos , Anticoncepcionais/administração & dosagem , Prestação Integrada de Cuidados de Saúde/métodos , Características da Família , Serviços de Planejamento Familiar/métodos , Infecções por HIV/diagnóstico , Transmissão Vertical de Doenças Infecciosas/prevenção & controle , Adolescente , Adulto , Idoso , Terapia Comportamental/métodos , Anticoncepção/estatística & dados numéricos , Feminino , Infecções por HIV/tratamento farmacológico , Infecções por HIV/prevenção & controle , Educação em Saúde/métodos , Pesquisa sobre Serviços de Saúde , Humanos , Masculino , Pessoa de Meia-Idade , Gravidez , Adulto Jovem , Zâmbia
12.
Clin Infect Dis ; 56(12): 1829-37, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23487377

RESUMO

BACKGROUND: Syphilis continues to be a common sexually transmitted infection, despite the availability of inexpensive and effective treatment. Infection in human immunodeficiency virus (HIV)-discordant couples is important because syphilis increases the risk of HIV acquisition. Current US treatment guidelines recommend 1 dose of benzathine penicillin for early syphilis, irrespective of HIV status, but data from coinfected patients are limited. METHODS: Retrospective analysis of 1321 individuals in 2 African HIV-discordant couple cohorts was performed. Cox proportional hazards analysis and multivariable modeling were used to assess predictors of serologic response to treatment at 180 days and 400 days. Modeling was performed for all episodes of positive rapid plasma reagin (RPR) test results and on a subset with higher RPR titers (≥1:4). RESULTS: A total of 1810 episodes of syphilis among 1321 individuals were treated with penicillin between 2002 and 2008. Although a positive RPR was more common in the HIV-infected partners, HIV infection did not impact the likelihood of serologic response to therapy (odds ratio [OR], 1.001; P = .995). By 400 days, 67% had responded to therapy, 27% were serofast, and 6.5% had documented reinfection. Prevalent infections were more likely to remain serofast than incident infections (33% vs 20% at 400 days). CONCLUSIONS: In 2 HIV-serodiscordant couple cohorts in Africa, incident syphilis had a very good likelihood of response to penicillin therapy, irrespective of HIV infection. This supports current Centers for Disease Control and Prevention treatment guidelines. A high proportion of prevalent RPR-positive infections remain serofast despite treatment.


Assuntos
Infecções por HIV/microbiologia , Cônjuges/estatística & dados numéricos , Sífilis/tratamento farmacológico , Sífilis/virologia , Adolescente , Adulto , Antitreponêmicos/uso terapêutico , Feminino , Infecções por HIV/epidemiologia , Soronegatividade para HIV , Humanos , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Penicilinas/uso terapêutico , Modelos de Riscos Proporcionais , Estudos Retrospectivos , Ruanda/epidemiologia , Sífilis/epidemiologia , Resultado do Tratamento , Zâmbia/epidemiologia
13.
Invest Ophthalmol Vis Sci ; 49(4): 1705-11, 2008 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-18385094

RESUMO

PURPOSE: Nicotinic acetylcholine receptors (nAChR) are best known for their role in neurotransmission, but they have recently been demonstrated on vascular endothelial cells. Acetylcholine is their endogenous ligand, but they are also stimulated by nicotine. By stimulating nAChR, nicotine promotes tumor angiogenesis as well as atherosclerotic plaque neovascularization. In this study, the authors investigated the role of nAChR in the pathogenesis of choroidal neovascularization (CNV). METHODS: The effect of the nonselective nAChR antagonist mecamylamine was tested on human retinal and choroidal endothelial cells in vitro and in a murine model of CNV. RESULTS: Several nAChR isoforms were identified in retinal and choroidal microvascular endothelial cells, and the ability of these cells to form tubules when grown in growth factor-reduced basement membrane matrix and supplemented with VEGF was suppressed by the nAChR antagonist mecamylamine. Supplementation of the drinking water of mice with nicotine increased the size of CNV lesions at Bruch membrane rupture sites, an effect that was blocked by subcutaneous administration of mecamylamine (50 mg/kg/d) by an osmotic pump. In the absence of nicotine, CNV formation was suppressed by the infusion of 50 mg/kg/d mecamylamine or by topical application 0.1 or 1% mecamylamine to the cornea. CONCLUSIONS: These data suggest that endogenous activation of nAChR promotes CNV and that activation of nAChR by nicotine may contribute to the increased incidence of CNV seen in smokers with age-related macular degeneration (AMD). Topically administered mecamylamine could provide an appealing new treatment approach for CNV.


Assuntos
Neovascularização de Coroide/prevenção & controle , Modelos Animais de Doenças , Endotélio Vascular/efeitos dos fármacos , Mecamilamina/farmacologia , Nicotina/farmacologia , Antagonistas Nicotínicos/farmacologia , Receptores Nicotínicos/metabolismo , Animais , Células Cultivadas , Corioide/irrigação sanguínea , Neovascularização de Coroide/etiologia , Neovascularização de Coroide/metabolismo , Endotélio Vascular/metabolismo , Feminino , Humanos , Immunoblotting , Mecamilamina/administração & dosagem , Camundongos , Camundongos Endogâmicos C57BL , Isoformas de Proteínas/metabolismo , RNA Mensageiro/metabolismo , Receptores Nicotínicos/genética , Vasos Retinianos/citologia
14.
FASEB J ; 21(12): 3219-30, 2007 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-17522382

RESUMO

Hypoxia causes increased expression of several proteins that have the potential to promote neovascularization. Vascular endothelial growth factor (VEGF) is up-regulated by hypoxia in the retina and plays a central role in the development of several types of ocular neovascularization, but the effects of other hypoxia-regulated proteins are less clear. Stromal-derived factor-1 (SDF-1) and its receptor, CXCR4, have hypoxia response elements in the promoter regions of their genes and are increased in hypoxic liver and heart. In this study, we found that SDF-1 and CXCR4 are increased in hypoxic retina, with SDF-1 localized in glial cells primarily near the surface of the retina and CXCR4 localized in bone marrow-derived cells. Glial cells also expressed CXCR4, which suggested the possibility of autocrine stimulation, but influx of bone marrow-derived cells is the major source of increased levels of CXCR4. High levels of VEGF in the retina in the absence of hypoxia also increased levels of Cxcr4 and Sdf1 mRNA. CXCR4 antagonists reduced influx of bone marrow-derived cells into ischemic retina and strongly suppressed retinal neovascularization, VEGF-induced subretinal neovascularization, and choroidal neovascularization. These data suggest that SDF-1 and CXCR4 contribute to the involvement of bone marrow-derived cells and collaborate with VEGF in the development of several types of ocular neovascularization. They provide new targets for therapeutic intervention that may help to bolster and supplement effects obtained with VEGF antagonists.


Assuntos
Quimiocina CXCL12/metabolismo , Neovascularização da Córnea , Hipóxia , Receptores CXCR4/metabolismo , Retina/anatomia & histologia , Retina/fisiologia , Neovascularização Retiniana , Animais , Antígenos de Diferenciação/metabolismo , Células da Medula Óssea , Quimiocina CXCL12/genética , Humanos , Isquemia/metabolismo , Antígenos Comuns de Leucócito/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Oligopeptídeos/metabolismo , Molécula-1 de Adesão Celular Endotelial a Plaquetas/genética , Molécula-1 de Adesão Celular Endotelial a Plaquetas/metabolismo , Piridinas/metabolismo , Receptores CXCR4/antagonistas & inibidores , Receptores CXCR4/genética , Retina/patologia , Fator A de Crescimento do Endotélio Vascular/genética , Fator A de Crescimento do Endotélio Vascular/metabolismo
15.
Exp Eye Res ; 83(5): 1260-7, 2006 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-16950258

RESUMO

Periocular injections of the polyamine analog CGC-11144 three times a week causes regression of choroidal neovascularization. This regimen was selected to maximize chances of success for proof of concept, but is not ideal for clinical application. In this study we explored other regimens for periocular delivery of CGC-11144, and 2 other polyamine analogs, CGC-11047 and CGC-11093. A single periocular injection of 200 microg of CGC-11144, 2 mg of CGC-11047, or 1.5 mg of CGC-11093 caused significant suppression and regression of laser-induced choroidal neovascularization. An injection of 2 mg of CGC-11047 or 1.5 mg of CGC-11093 one or two weeks before, but not 3 weeks before, rupture of Bruch's membrane also caused significant suppression. Periocular injection of polyamine analogs also caused strong inhibition of retinal or subretinal neovascularization in mice with oxygen-induced ischemic retinopathy or Rhodopsin promoter/VEGF transgenic mice, respectively. These data suggest that periocular injection of one of 3 different polyamine analogs inhibits retinal or choroidal neovascularization and a single injection provides inhibitory activity for at least 2 to 3 weeks, which could provide the basis for a feasible treatment regimen for clinical trials.


Assuntos
Poliaminas Biogênicas/administração & dosagem , Neovascularização de Coroide/tratamento farmacológico , Soluções Oftálmicas/administração & dosagem , Animais , Lâmina Basilar da Corioide/lesões , Modelos Animais de Doenças , Esquema de Medicação , Feminino , Injeções Intraperitoneais , Isquemia/tratamento farmacológico , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Oxigênio , Células Fotorreceptoras de Vertebrados/química , Poliaminas/farmacologia , Neovascularização Retiniana/tratamento farmacológico , Vasos Retinianos/efeitos dos fármacos , Ruptura , Fatores de Tempo , Resultado do Tratamento , Fator A de Crescimento do Endotélio Vascular/análise
16.
J Cell Physiol ; 208(1): 161-6, 2006 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-16557520

RESUMO

Vascular endothelial cells receive proangiogenic or antiangiogenic signals from components of extracellular matrix (ECM) depending upon the situation and many molecular signals can have opposite effects in different vascular beds. Tissue inhibitor of metalloproteinase 1 is antiangiogenic in several tissues, but promotes retinal neovascularization. When cleaved from native collagens, several of the non-collagenous domains (NC1) of basement membrane collagens have antiangiogenic effects in some tissues, but this is context dependent for the NC1 of the alpha 1 chain of collagen IV. It is critical to examine effects in several well-defined model systems before assuming that an ECM component is universally antiangiogenic. In this study, we examined the effects of a recombinant fragment of NC1 of the alpha 2 chain of type IV collagen (alpha2(IV)NC1) in a well-characterized model of ocular neovascularization. Intravitreous or periocular injections of alpha2(IV)NC1 caused selective apoptosis of endothelial cells participating in neovascularization resulting in suppression of neovascularization when the peptide was given prior to onset of new vessel sprouting. Importantly, when the peptide was given after neovascularization had already developed, it caused the new vessels to regress. This suggests that alpha2(IV)NC1, which has previously been shown to suppress tumor angiogenesis in xenograft models, is also a strong antiangiogenic agent in the choroid and is a therapeutic candidate for treatment of neovascular age-related macular degeneration.


Assuntos
Apoptose/efeitos dos fármacos , Neovascularização de Coroide/prevenção & controle , Colágeno Tipo IV/farmacologia , Neovascularização Fisiológica/efeitos dos fármacos , Proteínas Recombinantes/farmacologia , Inibidores da Angiogênese/farmacologia , Inibidores da Angiogênese/uso terapêutico , Animais , Apoptose/fisiologia , Corioide/irrigação sanguínea , Corioide/efeitos dos fármacos , Corioide/patologia , Corioide/fisiopatologia , Neovascularização de Coroide/etiologia , Neovascularização de Coroide/fisiopatologia , Células Endoteliais/efeitos dos fármacos , Células Endoteliais/patologia , Células Endoteliais/fisiologia , Matriz Extracelular/fisiologia , Feminino , Marcação In Situ das Extremidades Cortadas , Injeções , Lasers , Degeneração Macular/tratamento farmacológico , Camundongos , Camundongos Endogâmicos C57BL , Neovascularização Fisiológica/fisiologia , Estrutura Terciária de Proteína
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...