Effect of antiplatelet agents and tyrosine kinase inhibitors on oxLDL-mediated procoagulant platelet activity.

Low-density lipoprotein (LDL) contributes to atherogenesis and cardiovascular disease through interactions with peripheral blood cells, especially platelets. However, mechanisms by which LDL affects platelet activation and atherothrombosis, and how to best therapeutically target and safely prevent such responses remain unclear. Here, we investigate how oxidized low-density lipoprotein (oxLDL) enhances glycoprotein VI (GPVI)-mediated platelet hemostatic and procoagulant responses, and how traditional and emerging antiplatelet therapies affect oxLDL-enhanced platelet procoagulant activity ex vivo. Human platelets were treated with oxLDL and the GPVI-specific agonist, crosslinked collagen-related peptide, and assayed for hemostatic and procoagulant responses in the presence of inhibitors of purinergic receptors (P2YR), cyclooxygenase (COX), and tyrosine kinases. Ex vivo, oxLDL enhanced GPVI-mediated platelet dense granule secretion, α-granule secretion, integrin activation, thromboxane generation and aggregation, as well as procoagulant phosphatidylserine exposure and fibrin generation. Studies of washed human platelets, as well as platelets from mouse and nonhuman primate models of hyperlipidemia, further determined that P2YR antagonists (eg, ticagrelor) and Bruton tyrosine kinase inhibitors (eg, ibrutinib) reduced oxLDL-mediated platelet responses and procoagulant activity, whereas COX inhibitors (eg, aspirin) had no significant effect. Together, our results demonstrate that oxLDL enhances GPVI-mediated platelet procoagulant activity in a manner that may be more effectively reduced by P2YR antagonists and tyrosine kinase inhibitors compared with COX inhibitors.

Platelets and tyrosine kinase inhibitors: clinical features, mechanisms of action, and effects on physiology.

Tyrosine kinase inhibitors (TKIs) have emerged as a promising class of target-directed, small molecule inhibitors used to treat hematologic malignancies, inflammatory diseases, and autoimmune disorders. Recently, TKIs have also gained interest as potential antiplatelet-directed therapeutics that could be leveraged to reduce pathologic thrombus formation and atherothrombotic complications, while minimally affecting platelet hemostatic function. This review provides a mechanistic overview and summarizes the known effects of tyrosine kinase inhibitors on platelet signaling and function, detailing prominent platelet signaling pathways downstream of the glycoprotein VI (GPVI) receptor, integrin αIIbß3, and G protein-coupled receptors (GPCRs). This review focuses on mechanistic as well as clinically relevant and emerging TKIs targeting major families of tyrosine kinases including but not limited to Bruton's tyrosine kinase (BTK), spleen tyrosine kinase (Syk), Src family kinases (SFKs), Janus kinases (JAK), and signal transducers and activators of transcription (STAT) and evaluates their effects on platelet aggregation and adhesion, granule secretion, receptor expression and activation, and protein phosphorylation events. In summation, this review highlights current advances and knowledge on the effects of select TKIs on platelet biology and furthers insight on signaling pathways that may represent novel druggable targets coupled to specific platelet functional responses.

Ibrutinib Inhibits BMX-Dependent Endothelial VCAM-1 Expression In Vitro and Pro-Atherosclerotic Endothelial Activation and Platelet Adhesion In Vivo.

Introduction: Inflammatory activation of the vascular endothelium leads to overexpression of adhesion molecules such as vascular cell adhesion molecule-1 (VCAM-1), contributing to the pro-thrombotic state underpinning atherogenesis. While the role of TEC family kinases (TFKs) in mediating inflammatory cell and platelet activation is well defined, the role of TFKs in vascular endothelial activation remains unclear. We investigated the role of TFKs in endothelial cell activation in vitro and in a nonhuman primate model of diet-induced atherosclerosis in vivo. Methods and Results: In vitro, we found that ibrutinib blocked activation of the TFK member, BMX, by vascular endothelial growth factors (VEGF)-A in human aortic endothelial cells (HAECs). Blockade of BMX activation with ibrutinib or pharmacologically distinct BMX inhibitors eliminated the ability of VEGF-A to stimulate VCAM-1 expression in HAECs. We validated that treatment with ibrutinib inhibited TFK-mediated platelet activation and aggregation in both human and primate samples as measured using flow cytometry and light transmission aggregometry. We utilized contrast-enhanced ultrasound molecular imaging to measure platelet GPIbα and endothelial VCAM-1 expression in atherosclerosis-prone carotid arteries of obese nonhuman primates. We observed that the TFK inhibitor, ibrutinib, inhibited platelet deposition and endothelial cell activation in vivo. Conclusion: Herein we found that VEGF-A signals through BMX to induce VCAM-1 expression in endothelial cells, and that VCAM-1 expression is sensitive to ibrutinib in vitro and in atherosclerosis-prone carotid arteries in vivo. These findings suggest that TFKs may contribute to the pathogenesis of atherosclerosis and could represent a novel therapeutic target.

Revised model of the tissue factor pathway of thrombin generation: Role of the feedback activation of FXI.

BACKGROUND: Biochemical reaction networks are self-regulated in part due to feedback activation mechanisms. The tissue factor (TF) pathway of blood coagulation is a complex reaction network controlled by multiple feedback loops that coalesce around the serine protease thrombin. OBJECTIVES: Our goal was to evaluate the relative contribution of the feedback activation of coagulation factor XI (FXI) in TF-mediated thrombin generation using a comprehensive systems-based analysis. MATERIALS AND METHODS: We developed a systems biology model that improves the existing Hockin-Mann (HM) model through an integrative approach of mathematical modeling and in vitro experiments. Thrombin generation measured using in vitro assays revealed that the feedback activation of FXI contributes to the propagation of thrombin generation based on the initial concentrations of TF or activated coagulation factor X (FXa). We utilized experimental data to improve the robustness of the HM model to capture thrombin generation kinetics without a role for FXI before including the feedback activation of FXI by thrombin to construct the extended (ext.) HM model. RESULTS AND CONCLUSIONS: Using the ext.HM model, we predicted that the contribution of positive feedback of FXI activation by thrombin can be abolished by selectively eliminating the inhibitory function of tissue factor pathway inhibitor (TFPI), a serine protease inhibitor of FXa and TF-activated factor VII (FVIIa) complex. This prediction from the ext.HM model was experimentally validated using thrombin generation assays with function blocking antibodies against TFPI and plasmas depleted of FXI. Together, our results demonstrate the applications of combining experimental and modeling techniques in predicting complex biochemical reaction systems.

Thrombotic events in patients using cyclin dependent kinase 4/6 inhibitors, analysis of existing ambulatory risk assessment models and the potential influences of tumor specific risk factors.

Cyclin dependent kinase 4 of 6 inhibitors (CDKi) are key therapeutics in the treatment of advanced breast cancer and have recently been approved in small cell lung cancer for the prevention of myelosuppression. Thrombotic events have emerged as a significant treatment related adverse event in up to 5% of patients in clinical trials and has been reported at higher rates, up to 10%, in real world analysis. The prothrombotic mechanisms of CDKis, however, remain unknown. Cancer specific risk assessment models exist to identify who may be at highest risk of thrombosis and who could potentially benefit from prophylactic anticoagulation. However, these models may not be accurate in patients taking CDKis and may not fully capture recently identified thrombotic risk factors such as tumor specific somatic mutations. In the following manuscript, we summarize the literature on thrombotic events with CDKis in clinical trials and real-world settings, review the existing thrombosis risk assessment models for ambulatory cancer patients, and discuss the literature on tumor mutations and role in cancer associated thrombosis.

The Toll-Like Receptor 2 Ligand Pam2CSK4 Activates Platelet Nuclear Factor-κB and Bruton's Tyrosine Kinase Signaling to Promote Platelet-Endothelial Cell Interactions.

Circulating platelets establish a variety of immunological programs and orchestrate inflammatory responses at the endothelium. Platelets express the innate immunity family of Toll-like receptors (TLRs). While TLR2/TLR1 ligands are known to activate platelets, the effects of TLR2/TLR6 ligands on platelet function remain unclear. Here, we aim to determine whether the TLR2/TLR6 agonists Pam2CSK4 and FSL-1 activate human platelets. In addition, human umbilical vein endothelial cells (HUVECs) and platelets were co-cultured to analyze the role of platelet TLR2/TLR6 on inflammation and adhesion to endothelial cells. Pam2CSK4, but not FSL-1, induced platelet granule secretion and integrin αIIbß3 activation in a concentration-dependent manner. Moreover, Pam2CSK4 promoted platelet aggregation and increased platelet adhesion to collagen-coated surfaces. Mechanistic studies with blocking antibodies and pharmacologic inhibitors demonstrated that the TLR2/Nuclear factor-κB axis, Bruton's-tyrosine kinase, and a secondary ADP feedback loop are involved in Pam2CSK4-induced platelet functional responses. Interestingly, Pam2CSK4 showed cooperation with immunoreceptor tyrosine-based activation motif (ITAM)-mediated signaling to enhance platelet activation. Finally, the presence of platelets increased inflammatory responses in HUVECs treated with Pam2CSK4, and platelets challenged with Pam2CSK4 showed increased adhesion to HUVECs under static and physiologically relevant flow conditions. Herein, we define a functional role for platelet TLR2-mediated signaling, which may represent a druggable target to dampen excessive platelet activation in thrombo-inflammatory diseases.

Assessment of the effects of Syk and BTK inhibitors on GPVI-mediated platelet signaling and function.

Spleen tyrosine kinase (Syk) and Bruton's tyrosine kinase (BTK) play critical roles in platelet physiology, facilitating intracellular immunoreceptor tyrosine-based activation motif (ITAM)-mediated signaling downstream of platelet glycoprotein VI (GPVI) and GPIIb/IIIa receptors. Small molecule tyrosine kinase inhibitors (TKIs) targeting Syk and BTK have been developed as antineoplastic and anti-inflammatory therapeutics and have also gained interest as antiplatelet agents. Here, we investigate the effects of 12 different Syk and BTK inhibitors on GPVI-mediated platelet signaling and function. These inhibitors include four Syk inhibitors, Bay 61-3606, R406 (fostamatinib), entospletinib, TAK-659; four irreversible BTK inhibitors, ibrutinib, acalabrutinib, ONO-4059 (tirabrutinib), AVL-292 (spebrutinib); and four reversible BTK inhibitors, CG-806, BMS-935177, BMS-986195, and fenebrutinib. In vitro, TKIs targeting Syk or BTK reduced platelet adhesion to collagen, dense granule secretion, and alpha granule secretion in response to the GPVI agonist cross-linked collagen-related peptide (CRP-XL). Similarly, these TKIs reduced the percentage of activated integrin αIIbß3 on the platelet surface in response to CRP-XL, as determined by PAC-1 binding. Although all TKIs tested inhibited phospholipase C γ2 (PLCγ2) phosphorylation following GPVI-mediated activation, other downstream signaling events proximal to phosphoinositide 3-kinase (PI3K) and PKC were differentially affected. In addition, reversible BTK inhibitors had less pronounced effects on GPIIb/IIIa-mediated platelet spreading on fibrinogen and differentially altered the organization of PI3K around microtubules during platelets spreading on fibrinogen. Select TKIs also inhibited platelet aggregate formation on collagen under physiological flow conditions. Together, our results suggest that TKIs targeting Syk or BTK inhibit central platelet functional responses but may differentially affect protein activities and organization in critical systems downstream of Syk and BTK in platelets.

Do the same socio-demographic variables predict testing uptake and sero-status? HIV and syphilis among an observational sample of Chinese men who have sex with men in Shanghai, China.

HIV and syphilis are pronounced among men who have sex with men (MSM) in China and often occur as co-infections, while testing remains low. Few studies examine common predictors across these outcomes. This observational venue-based sample of 546 MSM in Shanghai, China used a common set of psychosocial predictors to construct logistic models for the outcomes (HIV non-testing, syphilis non-testing, HIV sero-status, and syphilis sero-status). Fifty-seven (10.7%) participants tested positive for HIV, 126 (23.5%) for syphilis, and 33% of HIV-positive participants had a co-infection. Non-sex working MSM had consistently higher odds of HIV and syphilis non-testing (OR= 2.2, 95% CI 1.4-3.5, p < 0.001; OR = 2.4, 95, 95% CI 1.5-3.8, p < 0.001, respectively) compared to 'money boy' sex workers. Participants with a 0 score on HIV knowledge had 4.1 times (95% CI 1.4-12.5, p = 0.01) the odds of reporting HIV non-testing, 6.0 (95% CI 1.96-18.5, p < 0.01) times the odds of reporting non-testing for syphilis, and 8.44 times (95% CI 1.19-59.7, p = 0.03) the odds of testing positive for HIV, compared to a score of 8. The results highlighted the importance of integrating HIV/syphilis education and promoting testing for both HIV and syphilis among all sub-groups of MSM in China.

Phosphoproteomic quantitation and causal analysis reveal pathways in GPVI/ITAM-mediated platelet activation programs.

Platelets engage cues of pending vascular injury through coordinated adhesion, secretion, and aggregation responses. These rapid, progressive changes in platelet form and function are orchestrated downstream of specific receptors on the platelet surface and through intracellular signaling mechanisms that remain systematically undefined. This study brings together cell physiological and phosphoproteomics methods to profile signaling mechanisms downstream of the immunotyrosine activation motif (ITAM) platelet collagen receptor GPVI. Peptide tandem mass tag (TMT) labeling, sample multiplexing, synchronous precursor selection (SPS), and triple stage tandem mass spectrometry (MS3) detected >3000 significant (false discovery rate < 0.05) phosphorylation events on >1300 proteins over conditions initiating and progressing GPVI-mediated platelet activation. With literature-guided causal inference tools, >300 site-specific signaling relations were mapped from phosphoproteomics data among key and emerging GPVI effectors (ie, FcRγ, Syk, PLCγ2, PKCδ, DAPP1). Through signaling validation studies and functional screening, other less-characterized targets were also considered within the context of GPVI/ITAM pathways, including Ras/MAPK axis proteins (ie, KSR1, SOS1, STAT1, Hsp27). Highly regulated GPVI/ITAM targets out of context of curated knowledge were also illuminated, including a system of >40 Rab GTPases and associated regulatory proteins, where GPVI-mediated Rab7 S72 phosphorylation and endolysosomal maturation were blocked by TAK1 inhibition. In addition to serving as a model for generating and testing hypotheses from omics datasets, this study puts forth a means to identify hemostatic effectors, biomarkers, and therapeutic targets relevant to thrombosis, vascular inflammation, and other platelet-associated disease states.

Management of retrosternal goiter: Retrospective study of 72 patients at two secondary care centers.

OBJECTIVE: Data pertaining to the outcomes of retrosternal goiter surgeries performed at secondary care centers, where thoracic surgery expertise is not readily available, is infrequently reported. Careful patient selection is crucial to avoid an unexpected need for a sternotomy during surgery. We sought to evaluate the surgical management of patients with retrosternal goiters treated at two secondary care centers. METHODS: Retrospective review of clinical records and computed tomographic (CT) scans of 557 patients who underwent thyroid surgery at the Departments of Otolaryngology, Head and Neck Surgery of Manukau Surgery Center and Whangarei Base Hospital. Inclusion criterion was extension of goiter below the plane of the thoracic inlet on CT scan. Clinicopathologic features and surgical outcomes were recorded. RESULTS: The prevalence of retrosternal goiter was 72 of 557 patients (12.9%). All patients in this series underwent thyroidectomy transcervically. Dyspnea was present in 48 patients (66.7%). On preoperative CT scans, the goiter was noted to extend beyond the aortic arch in seven patients (9.7%), tracheal bifurcation in five patients (6.9%) and posterior mediastinum in 15 patients (20.8%). Malignancy was diagnosed in eight patients (11.1%) histologically. Postoperatively, vocal cord paralysis was temporary in 5 patients (6.9%) and permanent in 1 patient (1.4%). Hypocalcaemia was transient in 10 patients (13.9%). No permanent hypocalcemia, tracheomalacia, postoperative hematoma or patient death was reported. During the study period, 4 patients were encountered in the outpatients setting whereby the evaluation of their CT imaging demonstrated features deemed to be at high risk of requiring a sternotomy: primary mediastinal goiter (n=2) and inferior extent of goiter to the level of right atrium (n=2). These patients were pre-emptively referred to a tertiary center where thoracic surgery service was available and their data was reported separately. CONCLUSION: With careful patient selection, the majority of retrosternal goiter can be resected transcervically with minimal morbidities. Preoperative CT scan yielded useful surgical information; in the presence of primary mediastinal goiter or inferior extent of goiter to the level of the right atrium, surgery should be planned in a tertiary center where thoracic surgeon is available.

Estimating self-reported sex practices, drug use, depression, and intimate partner violence among MSM in China: a comparison of three recruitment methods.

Men who have sex with men (MSM) are the group at highest risk for HIV in China. Researchers have used various recruitment methods to reach this population hidden from the hetero-normative culture. To inform future recruitment strategies, we compared estimates of socio-demographic characteristics, HIV risk behaviors, depression, and intimate partner violence (IPV) across three samples of MSM and money boys in Shanghai, China. Data were collected from three community-based samples of MSM and money boys (n = 1352) recruited via respondent-driven sampling (RDS) (n = 404), community popular opinion leaders (CPOL) (n = 385), and Internet and venue-based sampling (VBS) (n = 546). Different recruitment methods generated samples with statistically significant differences among a number of socio-demographic characteristics, sexual behaviors, drug use, depression scores, and exposure to IPV. Specifically, RDS participants had lower education (p = .002), income levels (p < .001), and were more likely to report condomless sex with a woman (p < .001). CPOL participants were younger (p < .001), more likely to report lifetime condomless anal sex (p = .009), more than 10 male partners in the past 30 days (p < .001), and were less likely to experience violence by a male intimate partner (p = .001). VBS participants had lowest depression score (p = .005) and were more likely to report lifetime drug use (p = .003). Our findings reinforce that each recruitment method may reach a sub-group of MSM with a specific risk profile, so multiple methods may be needed to obtain a representative sample of MSM. Interventions may use specific recruitment methods to target certain segments of the MSM population.

Validity of the CAGE questionnaire for men who have sex with men (MSM) in China.

BACKGROUND: Detection of heavy drinking among men who have sex with men (MSM) is crucial for both intervention and treatment. The CAGE questionnaire is a popular screening instrument for alcohol use problems. However, the validity of CAGE for Chinese MSM is unknown. METHOD: Data were from three waves of cross-sectional assessments among general MSM (n=523) and men who sell sex to other men ("money boys" or MBs, n=486) in Shanghai, China. Specifically, participants were recruited using respondent-driven, community popular opinion leader, and venue-based sampling methods. The validity of the CAGE was examined for different cutoff scores and individual CAGE items using self-reported heavy drinking (≥14 drinks in the past week) as a criterion. RESULTS: In the full sample, 75 (7.4%) of participants were classified as heavy drinkers. 32 (6.1%) of general MSM and 43 (8.9%) of MBs were heavy drinkers. The area under curve statistics for overall sample was 0.7 (95% CI: 0.36-0.77). Overall, the sensitivities (ranging from 18.7 to 66.7%), specificities (ranging from 67.5 to 95.8%), and positive predictive values (ranging from 14.1 to 26.4%) for different cutoff scores were inadequate using past week heavy drinking as the criterion. The ability of CAGE to discriminate heavy drinkers from non-heavy drinkers was limited. CONCLUSIONS: Our findings showed the inadequate validity of CAGE as a screening instrument for current heavy drinking in Chinese MSM. Further research using a combination of validity criteria is needed to determine the applicability of CAGE for this population.

Paradoxical Motor Recovery From a First Stroke After Induction of a Second Stroke: Reopening a Postischemic Sensitive Period.

BACKGROUND AND OBJECTIVE: Prior studies have suggested that after stroke there is a time-limited period of increased responsiveness to training as a result of heightened plasticity-a sensitive period thought to be induced by ischemia itself. Using a mouse model, we have previously shown that most training-associated recovery after a caudal forelimb area (CFA) stroke occurs in the first week and is attributable to reorganization in a medial premotor area (AGm). The existence of a stroke-induced sensitive period leads to the counterintuitive prediction that a second stroke should reopen this window and promote full recovery from the first stroke. To test this prediction, we induced a second stroke in the AGm of mice with incomplete recovery after a first stroke in CFA. METHODS: Mice were trained to perform a skilled prehension (reach-to-grasp) task to an asymptotic level of performance, after which they underwent photocoagulation-induced stroke in CFA. After a 7-day poststroke delay, the mice were then retrained to asymptote. We then induced a second stroke in the AGm, and after only a 1-day delay, retrained the mice. RESULTS: Recovery of prehension was incomplete when training was started after a 7-day poststroke delay and continued for 19 days. However, a second focal stroke in the AGm led to a dramatic response to 9 days of training, with full recovery to normal levels of performance. CONCLUSIONS: New ischemia can reopen a sensitive period of heightened responsiveness to training and mediate full recovery from a previous stroke.

Epidemiological and molecular characteristics of HIV infection among money boys and general men who have sex with men in Shanghai, China.

To examine and compare the epidemiological and molecular characteristics of HIV infection between money boys (MBs) and general men who have sex with men (MSM) in Shanghai, China. Using a venue-based sampling strategy, a total of 535 MSM including 226 MBs and 309 general MSM were recruited to participate in a cross-sectional survey including a face-to-face questionnaire interview and HIV testing. Genotyping of HIV-1 pol gene was performed for HIV-positive participants. Compared with general MSM, MBs reported more sexual partners, more alcohol and drug use and more sex after alcohol or drug use. HIV prevalence was 10.7% overall, 14.6% for MBs and 7.8% for general MSM (p=0.011). Two independent multiple logistic regression analyses indicated that HIV infection was positively associated with non-Han ethnicity (Odds Ratio [OR]=4.79, 95% Confidence Interval [CI]: 1.08-21.28) and sex after drug use in the past 6months (OR=3.59, 95% CI: 1.50-8.61) among MBs, and with sex after drug use in the past 6months (OR=3.38, 95% CI: 1.10-10.34) among general MSM as well. HIV-1 pol gene was successfully amplified and sequenced for 52 (91.2%) of HIV-positive participants. Of them, 53.8% were genotyped as CRF01_AE, 36.5% as CRF07_BC and 9.6% as subtype B. Two CRF01_AE subtype-infected participants (3.8%), a 50years old MB and a 24years old general MSM, harbored viruses with a M46L mutation conferring resistance to protease inhibitors (PI). MSM particularly MBs in Shanghai, China were at high risk of HIV infection, underscoring an urgent need for joint intervention efforts for drug use and sexual behaviors. HIV drug resistance surveillance is also warranted although the relatively low prevalence of HIV drug resistance implies the effectiveness of current antiretroviral treatment regimen.

Drug use and sexual behaviors among MSM in China.

BACKGROUND: This study explores patterns of drug use and related correlates among a sample of men who have sex with men (MSM) and men who sell sex to other men (aka "money boys") in China. OBJECTIVES: Data were collected from MSM and money boys (MBs) in Shanghai, China using a Community Popular Opinion Leader (CPOL) research design with a self-administered cross-sectional survey to: (1) describe drug use and drug use correlates and (2) examine relationships between drug use and sexual behaviors in general MSM and MBs. METHODS: The sample consisted of 402 MSM (203 MBs) who live in Shanghai, China. Descriptive statistics and regression analyses were used to explore associations between drug use and sexual behaviors and make comparisons between MBs and general MSM. RESULTS: MBs reported using more drugs in the last week, 3 months and ever; sex after using drugs, and unprotected sex after using drugs more frequently than general MSM. Additionally, many MBs reported receiving free drugs from their clients and those who did receive free drugs were very likely to report having unprotected sex. CONCLUSIONS: It is crucial to increase research and include Chinese MSM and their drug use in the Chinese policy conversation. These data suggest that drug use and sexual behaviors after drug use among Chinese MSM differ widely based upon selling sex and separate intervention strategies may be appropriate.

Social support and depressive symptoms among 'money' boys and general men who have sex with men in Shanghai, China.

The primary objective was to examine prevalence and correlates of social support and depressive symptoms among male sex workers (known as 'money boys' (MBs)) and general men who have sex with men (MSM) in Shanghai. The Social Provision Scale (SPS), which consists of 24 items, scored out of 4 for social provision, was used to evaluate the functions of social relationships. The score for each item ranges from 1 to 4, with a higher score indicating more social provision. The overall mean SPS score was 68.1 (s.d.=6.53) for MBs and 69.3 (s.d.=6.99) for general MSM. Depression was measured with a 12-item version of the Center for Epidemiological Studies Depression Scale (CES-D), where a score of 9 has been recommended as the cutoff score to indicate possible depressive symptoms. The prevalence of depressive symptoms was 57.9%, with MBs having a higher level of depressive symptoms than general MSM (70.0% v. 46.1%) (odds ratio=1.86, 95% confidence interval=1.07-3.24). Social support was a protective factor for depressive symptoms (odds ratio=0.92, 95% confidence interval=0.89-0.96). MSM in China, particularly MBs, are vulnerable to low social support and high depressive symptoms, highlighting the need for tailored psychological programs targeting this population.

Sexually transmitted infection testing practices among 'money boys' and general men who have sex with men in Shanghai, China: objective versus self-reported status.

Little is known about sexually transmitted infection (STI) testing among Chinese men who have sex with men (MSM). This study describes the prevalence of STI testing, associated factors and the validity of STI self-reporting among Chinese MSM. Findings indicated a high prevalence of STIs and low testing rates among MSM in Shanghai. Monthly income was significantly associated with STI testing (odds ratio: 0.37, 95% confidence interval (CI): 0.18 to 0.76). Depression was significantly associated with STI testing for general MSM (odds ratio: 1.09, 95% CI: 1.01 to 1.17). Syphilis self-reported status had the highest validity (k=0.33, χ(2)=3.76, 95% CI: -0.003 to 0.65). Efforts are needed to ensure that STI testing services are accessible to MSM in China. Future HIV and STI interventions should be tailored to the needs of different subsets of MSM.

Male-on-male intimate partner violence and sexual risk behaviors among money boys and other men who have sex with men in Shanghai, China.

BACKGROUND: Intimate partner violence (IPV) is known to increase HIV risk among heterosexual women, but less is known about IPV and HIV among men who have sex with men (MSM), with almost no data from non-Western countries. This study examined the prevalence of IPV and links between IPV and HIV risks among MSM in Shanghai, China. METHODS: A cross-sectional sample of 404 money boys (male sex workers) and other MSM were recruited via respondent-driven sampling. RESULTS: Overall, 51% of the sample reported emotional, physical, or sexual abuse from a male sexual partner. Money boys reported more overall abuse than did other MSM, and more were likely than other MSM to report experiencing multiple types of abuse. MSM who reported violence or abuse from male partners reported more overall sexual risk behavior, and specifically, more unprotected sex and more sex linked to alcohol and other substance use. The association between experience of abuse from male partners and increased HIV risk did not differ between money boys and other Chinese MSM. CONCLUSIONS: We conclude that violence and abuse from male partners are highly prevalent among Chinese MSM, and that experience of violence from male sexual partners is linked to increased HIV risk. HIV prevention targeting Chinese MSM must address the increased risk associated with experience of male-on-male IPV. Future research should explore links between HIV risk and MSM's perpetration of violence against male partners, as well as exploring the role of violence in the male-female relationships of men who have sex with and men and women.

Social network and other correlates of HIV testing: findings from male sex workers and other MSM in Shanghai, China.

Although the Chinese government provides free-of-charge voluntary HIV counseling and testing, HIV testing rates among men who have sex with men (MSM) are reported to be extremely low. This study examines the association of structural and psychosocial factors and social network characteristics with HIV testing behaviors among "money boys" and general MSM in Shanghai. Overall, 28.5% of "money boys" and 50.5% of general MSM had never tested for HIV despite high rates of reported HIV risk behaviors. Factors associated with not testing for HIV included: not knowing of a testing site, limited HIV knowledge, low perceived HIV risk, concern about HIV testing confidentiality, being a closeted gay, not using the Internet, and having a small social network or network with few members who had tested for HIV. Future efforts to promote HIV testing should focus on outreach to general MSM, confidentiality protection, decreasing the stigma of homosexuality, and encouraging peer education and support through the Internet and social networks.

Prevalence and correlates of alcohol use among a sample of general MSM and money boys in Shanghai, China.

The use and misuse of alcohol and their relation to risky sex have received modest scholarly attention in China. This type of research in high HIV/STI groups such as men who have sex with men (general MSM) and men who sell sex to other men ("money boys") (MB) in China is essentially absent. Therefore, the primary purpose of this exploratory study was to describe the types of alcohol consumed and levels of daily alcohol consumption among Chinese general MSM and MB in Shanghai, China. A secondary purpose was to explore demographic, lifetime sexual behavior, and psychosocial correlates of daily consumption levels. The sample consisted of 404 MSM (200 MB) who live in Shanghai, China. Participants were recruited using respondent-driven sampling and filled out a cross-sectional behavioral survey. Where appropriate, comparisons were made between MB and general MSM. Over 73% of participants reported drinking at least moderately every day. MB reported drinking Western red wine and other Western hard liquors (e.g., vodka) more frequently than general MSM. Conversely, general MSM consumed Chinese white wine more frequently than MB. Results from the regression analyses showed that MSM having higher lifetime sexual risks were more likely to drink in excess; though MB with greater social provisions were less likely to drink in excess. These results begin to highlight high levels of drinking and drinking-sexual risk relationships among groups of general MSM and MB and are useful for guiding intervention efforts among high-risk groups in China.