A Multi-Level Relation-Aware Transformer model for occluded person re-identification.

Occluded person re-identification (Re-ID) is a challenging task, as pedestrians are often obstructed by various occlusions, such as non-pedestrian objects or non-target pedestrians. Previous methods have heavily relied on auxiliary models to obtain information in unoccluded regions, such as human pose estimation. However, these auxiliary models fall short in accounting for pedestrian occlusions, thereby leading to potential misrepresentations. In addition, some previous works learned feature representations from single images, ignoring the potential relations among samples. To address these issues, this paper introduces a Multi-Level Relation-Aware Transformer (MLRAT) model for occluded person Re-ID. This model mainly encompasses two novel modules: Patch-Level Relation-Aware (PLRA) and Sample-Level Relation-Aware (SLRA). PLRA learns fine-grained local features by modeling the structural relations between key patches, bypassing the dependency on auxiliary models. It adopts a model-free method to select key patches that have high semantic correlation with the final pedestrian representation. In particular, to alleviate the interference of occlusion, PLRA captures the structural relations among key patches via a two-layer Graph Convolution Network (GCN), effectively guiding the local feature fusion and learning. SLRA is designed to facilitate the model to learn discriminative features by modeling the relations among samples. Specifically, to mitigate noisy relations of irrelevant samples, we present a Relation-Aware Transformer (RAT) block to capture the relations among neighbors. Furthermore, to bridge the gap between training and testing phases, a self-distillation method is employed to transfer the sample-level relations captured by SLRA to the backbone. Extensive experiments are conducted on four occluded datasets, two partial datasets and two holistic datasets. The results show that the proposed MLRAT model significantly outperforms existing baselines on four occluded datasets, while maintains top performance on two partial datasets and two holistic datasets.

Protective effects of methyl protodioscin against lipid disorders and liver injury in hyperlipidemic gerbils.

Methyl protodioscin (MPD) is the main component of total diosgenin, which was reported to reduce cholesterol and triglyceride levels potentially. This study aimed to investigate the beneficial effects of MPD against lipid disorder in hyperlipidemic gerbils induced by a high-fat diet (HFD). Hyperlipidemia was induced in gerbils by feeding them with HFD for six weeks, and a daily oral dose of MPD solution (25 and 50 mg/kg/day) was administered. This study investigated blood lipid levels and hepatic lipid accumulation in hyperlipidemic gerbils. The potential mechanism of MPD was explored by detecting the expression level of genes, including SREBPs, ACC, FASN, HMGCR, PCSK9, and LDL-R. The results showed that MPD treatment decreased the body weight, the relative weight of the liver, blood lipid, and hepatic lipid levels of gerbils fed with HFD. The administration of MPD alleviates liver steatosis and injury in gerbils fed with an HFD. MPD treatment reduced the expression of HMGCR, increased the expression of LDL-R, and decreased the expression of PCSK9 for cholesterol reduction. Additionally, MPD treatment reduced the expression of hepatic ACC and FASN for triglycerides reduction. The underlying mechanisms for these effects are attributed to MPD-induced inhibition of protein expression of LXR, SREBP1, and SREBP2. This study demonstrates that MPD protects gerbils against lipid disorders and liver injury by suppressing hepatic SREBPs expression.

Stigma toward mental disorders and associated factors among community mental health workers in Wuhan, China.

BACKGROUND: Stigma toward mental disorders (STMD) is a significant barrier to mental health service delivery. To improve the provision of mental health services for community-dwelling residents in China, this study investigated STMD and its associated factors in community mental health workers (CMHWs) in Wuhan, China. METHODS: In this cross-sectional study, a total of 3869 CMHWs (22.9% men and 37.1 ± 8.4 years old) were randomly selected through multistage sampling and invited to participate in this survey. The perceived devaluation-discrimination scale (PDD) and the National Mental Health Literacy Questionnaire (NMHLQ) were used to assess STMD and mental health knowledge, respectively. The presence of STMD was indicated by a mean item score of 3.0 or higher on the PDD. Multiple logistic regression was used to identify factors associated with STMD. RESULTS: Of the CMHWs, 41.9% had poor mental health knowledge (NMHLQ score < 80), and 18.5% exhibited STMD. In multiple regression analysis, factors significantly associated with STMD were social workers (vs. primary care physicians, OR = 1.44, p < .001), poor self-rated capacity to handle common mental health problems (vs. good, OR = 1.57, p < .001), and poor mental health knowledge (vs. NMHLQ score ≥ 80, OR = 1.46, p < .001). CONCLUSION: STMD is common among Chinese CMHWs. To reduce STMD among CMHWs, training programs in mental health care skills and mental health education may be necessary.

Can neurological soft signs and neurocognitive deficits serve as a combined endophenotype for Han Chinese with bipolar disorder?

BACKGROUND: Bipolar disorder's (BD) potential endophenotypes include neurological soft signs (NSS) and neurocognitive disorders (ND). Few research, meanwhile, has coupled NSS and ND as combined endophenotypes of BD. OBJECT: This study intends to investigate NSS and ND and compare their differences in euthymic patients with bipolar disorder (EBP), their unaffected first-degree relatives (FDR), and healthy controls (HC). Additionally, search for potential endophenotypic subprojects of NSS and ND and construct and verify a composite endophenotypic. METHODS: The subjects were all Han Chinese and consisted of 86 EBP, 81 FDR, and 81HC. Cambridge Neurological Inventory and MATRICSTM Consensus Cognitive Battery tested NSS and ND independently. RESULTS: All three groups displayed a trapezoidal distribution of NSS levels and cognitive abnormalities, with EBP having the most severe NSS levels and cognitive deficits, followed by FDR and HC. Among them, motor coordination in NSS and Information processing speed (IPS), Verbal learning (VL), and Working memory (WM) in neurocognitive function are consistent with the traits of the endophenotype of BD. The accuracy in differentiating EBP and HC or FDRs and HC was higher when these items were combined as predictor factors than in differentiating EBP and FDR. CONCLUSION: These results provide more evidence that motor coordination, IPS, VL, and WM may be internal characteristics of bipolar disease. When these characteristics are combined into a complex endophenotype, it may be possible to distinguish BD patients and high-risk groups from normal populations.

Preparation and Physico-Chemical Characterization of OSA-Modified Starches from Different Botanical Origins and Study on the Properties of Pickering Emulsions Stabilized by These Starches.

Native starch (NS) from different botanical origins (native rice/tapioca/oat starch, NRS/NTS/NOS) were hydrophobically modified by octenyl succinic anhydride (OSA), and the octenyl succinic (OS) groups were successfully introduced in the starch molecules which obtained OS-starch (OSRS, OSTS and OSOS) with different levels of modification (0.5%, 1.0%, 1.5%, 2.0%, 2.5%, 3.0%) and degree of substitution (DS). The structural properties of the OS-starch, such as granule size, crystal, wettability and morphology were studied, and the OS-starch was used as particulate stabilizers to produce oil-in-water (O/W) Pickering emulsions. The emulsion index, droplet size distribution and microstructures of Pickering emulsions produced by different OS-starches were compared. OSA modification had almost no effect on the morphology or crystal structure types of three kinds of NS and OS-starch but markedly increased the contact angle and particle size distribution of OSRS, OSTS and OSOS. Esterification reaction of OSA and starch mainly occurred in amorphous regions of starch, and the OSA significantly improved the emulsifying capacity of OSRS, OSTS and OSOS granules and thus stabilized emulsions formed at higher levels (2.5% and 3.0%) of modification of OS-Starch exhibited better stability; the ability of OS-starch to stabilize Pickering emulsion was 3.0% OSRS > 3.0% OSOS > 3.0% OSTS, respectively. Observation and structural properties analysis of OS-starch granules and Pickering emulsion droplets showed that the number and thickness of the starch granules on the oil-water interface of the emulsion droplets increased with improvement of the OSA modification level, and an aggregation state was formed between the OS-starch granules, which was also enhanced with the OSA modification levels. These were all necessary for the Pickering emulsion stabilized by starch granules to remain in a steady state.

Effectiveness of Group Patient-Led Life Skills Training on Function and Self-Efficacy for People With Schizophrenia: A Quasi-Experimental Study.

The current quasi-experimental study evaluated the effectiveness of group patient-led life skills training (LST) on functional recovery and self-efficacy of people with schizophrenia. Two psychiatric units in a mental health center were randomly assigned to intervention (first psychiatric unit) and control (second psychiatric unit) groups. Convenience sampling was used to recruit participants. The intervention group (n = 51) received group patient-led LST, and the control group (n = 53) received routine mental health care services. Outcomes on patients' functional recovery and self-efficacy between groups were compared at baseline, during the intervention (4 weeks), and immediately after the intervention (8 weeks). Repeated measures analysis of variance was used to analyze the data. Results showed that the intervention improved functional recovery and self-efficacy of people with schizophrenia (p < 0.05). Therefore, it is recommended that group patient-led LST be integrated in therapy for people with schizophrenia to facilitate their functional recovery and help them achieve their highest potential for independent living. [Journal of Psychosocial Nursing and Mental Health Services, 61(2), 60-67.].

Guiding Epilepsy Surgery with an LRP1-Targeted SPECT/SERRS Dual-Mode Imaging Probe.

Accurate identification of the resectable epileptic lesion is a precondition of operative intervention to drug-resistant epilepsy (DRE) patients. However, even when multiple diagnostic modalities are combined, epileptic foci cannot be accurately identified in ∼30% of DRE patients. Inflammation-associated low-density lipoprotein receptor-related protein-1 (LRP1) has been validated to be a surrogate target for imaging epileptic foci. Here, we reported an LRP1-targeted dual-mode probe that is capable of providing comprehensive epilepsy information preoperatively with SPECT imaging while intraoperatively delineating epileptic margins in a sensitive high-contrast manner with surface-enhanced resonance Raman scattering (SERRS) imaging. Notably, a novel and universal strategy for constructing self-assembled monolayer (SAM)-based Raman reporters was proposed for boosting the sensitivity, stability, reproducibility, and quantifiability of the SERRS signal. The probe showed high efficacy to penetrate the blood-brain barrier. SPECT imaging showed the probe could delineate the epileptic foci clearly with a high target-to-background ratio (4.11 ± 0.71, 2 h). Further, with the assistance of the probe, attenuated seizure frequency in the epileptic mouse models was achieved by using SPECT together with Raman images before and during operation, respectively. Overall, this work highlights a new strategy to develop a SPECT/SERRS dual-mode probe for comprehensive epilepsy surgery that can overcome the brain shift by the co-registration of preoperative SPECT and SERRS intraoperative images.

Vortioxetine Modulates the Regional Signal in First-Episode Drug-Free Major Depressive Disorder at Rest.

Background: Previous studies on brain functional alterations associated with antidepressants for major depressive disorder (MDD) have produced conflicting results because they involved short treatment periods and a variety of compounds. Methods: Resting-state functional magnetic resonance imaging scans were obtained from 25 first-episode drug-free patients with MDD and 25 healthy controls. The patients, who were treated with vortioxetine for 8 weeks, were scanned at two-time points (baseline and week 8 of treatment). The amplitude of low-frequency fluctuation (ALFF) in the imaging data was used to analyze local brain signal alterations associated with antidepressant treatment. Results: Compared with the controls, the patients at baseline showed decreased ALFF values in the right inferior temporal gyrus and increased ALFF values in the left inferior cerebellum, right cingulate gyrus and postcentral gyrus. After 8 weeks of vortioxetine treatment, patients showed increased ALFF values in the bilateral cingulate gyrus, middle temporal gyrus, medial superior frontal gyrus, and inferior cerebellum. Conclusion: This study provided evidence that vortioxetine modulates brain signals in MDD sufferers. These findings contribute to the understanding of how antidepressants effect brain function.

Preparation of a Fiber-Like 3D-Structured Adsorbent for CO2 Capture.

Solid amine adsorbents are promising materials to mitigate global warming. In this study, a commercially available melamine-formaldehyde sponge was adopted as a support to prepare a kind of solid amine adsorbent using polyethylenimine as a functional component and ethylene glycol diglycidyl ether as a cross-linker. The adsorbent, with abundant tunnels and a high amine loading amount, had a high adsorption capacity. When the amine loading was 89.6 wt%, the as-prepared adsorbent showed a high adsorption capacity of 7.29 mmol/g at 20 °C in the presence of water. The spent adsorbent could be easily regenerated by heating it at 90 °C, resulting in lower energy consumption. It has been proved by the Avrami model that physical and chemical adsorption coexist in the adsorption of CO2 on this adsorbent. Simulation with the intraparticle diffusion model has revealed that the rate-controlling step in the adsorption process was the gas film diffusion period when the adsorption temperature was below 30 °C, while it was the adsorption equilibrium period when the adsorption temperature was above 30 °C.

Preparation of a Solid Amine Microspherical Adsorbent with High CO2 Adsorption Capacity.

Amine-skeleton solid-amine materials are promising adsorbents for CO2 capture from flue gas. Here, a novel solid-amine microsphere was synthesized by cross-linking the skeleton poly(ethylenimine) (PEI) with ethylene glycol diglycidyl ether in a facile one-pot W/O emulsion system. The material had a remarkable CO2 adsorption capacity of 7.28 mmol/g in the presence of moisture at 20 °C, 0.1 bar. The highest ratio of breakthrough capacity to saturation capacity was ca. 84%. According to kinetic simulation, the Avrami kinetic model could better describe the adsorption process of CO2 under different temperatures, in which the value of R2 was above 0.99 and n was between 1 and 2, indicating that both physical and chemical adsorption mechanisms were performed during adsorption. Moreover, the material had a high swelling speed. Equilibrium was established within 30 s, and the swelling ratio was 271% at equilibrium. The saturated adsorbent could be easily regenerated with a regeneration efficiency of 94.63% after six cycles. The PEI microsphere appears to be a promising candidate material for CO2 capture from flue gas.

Neurological soft signs and neurocognitive deficits in remitted patients with schizophrenia, their first-degree unaffected relatives, and healthy controls.

Neurological soft signs (NSS) and neurocognitive deficits (ND) are highly prevalent in schizophrenia, and have been separately proposed as candidate endophenotypes of schizophrenia. However, few relevant studies focus on remitted patients with schizophrenia (RP) and integrate NSS and ND as a composite endophenotype. This study aimed to explore the NSS and ND and examine the comparative relationship between them in RP, their first-degree unaffected relatives (FDR), and healthy controls, furthermore, to seek potential endophenotypes subitems of NSS and ND and create a composite endophenotype. 86 RP, 86 FDR, and 86 healthy controls were included. NSS and ND were independently assessed with Cambridge Neurological Inventory and MATRICSTM Consensus Cognitive Battery. RP had more NSS and ND than FDR in all subitems except disinhibition, information processing speed, working memory, and visual memory. Similarly, FDR presented poorer performance than controls in all subscales except disinhibition, sensory integration, working memory, and visual memory. Six subitems of NSS and ND met the criteria of endophenotype and the three groups were most accurately classified (71.2%) with these subitems working as a composite endophenotype. Moreover, information processing speed, attention, and social cognition were associated with sensory integration in RP and FDR. These findings add evidences that certain subitems of NSS and ND might be the endophenotypes of schizophrenia and integrating these endophenotypes may prove useful in identifying schizophrenia and high-risk individuals. Furthermore, sensory integration and specific cognitive domains covary, hence suggesting an overlap of compromised underlying neural systems.

Adenylyl cyclase 1 as a major isoform to generate cAMP signaling for apoA-1-mediated cholesterol efflux pathway.

HDL apoA-1-mediated cholesterol efflux pathway requires multiple cellular proteins and signal transduction processes, including adenylyl cyclase (AC)/cAMP signaling. Due to the existence of multiple transmembrane AC isoforms, it was not known how many AC isoforms are expressed and which ones are essential for cholesterol efflux in macrophage foam cells. These questions were investigated in THP-1 macrophages in this study. Quantitative RT-PCR detected mRNAs for all nine transmembrane AC isoforms, but only the mRNA and protein of the AC1 isoform were consistently upregulated by cholesterol loading and apoA-1. AC1 shRNA interference decreased AC1 mRNA and protein levels, resulting in reduction of apoA-1-mediated cAMP production and cholesterol efflux, while the intracellular cholesterol levels remained high. Confocal microscopy showed that apoA-1 promoted translocation of cholesterol and formation of cholesterol-apoA-1 complexes (protrusions) on the cholesterol-loaded macrophage surface. AC1 shRNA-interfered macrophages showed no translocation of cholesterol to the cell surface. AC1 shRNA interference also disrupted cellular localization of the intracellular cholesterol indicator protein adipophillin, and the expression as well as surface translocation of ABCA1. Together, our results show that AC1 is a major isoform for apoA-1-activated cAMP signaling to promote cholesterol transport and exocytosis to the surface of THP-1 macrophage foam cells.

Assessment of the effect of Enteromorpha prolifera on bacterial community structures in aquaculture environment.

In recent years, Enteromorpha prolifera blooms had serious impacts on costal environments and fisheries in China. Nevertheless, the effects of E. prolifera on microbial ecology remain unknown. In this study, for the first time, an Illumina sequencing analysis was used to investigate bacterial communities in source water, aquaculture ponds with E. prolifera, and an aquaculture pond in which E. prolifera -free. Principal coordinate and phylogenic analyses revealed obvious differences among the bacterial communities in the pond water with and without E. prolifera. Abundant bacterial taxa in the E. prolifera-containing pond were generally absent from the pond without E. prolifera. Interestingly, pond water with E. prolifera was dominated by Actinomycetales (> 50%), as well as by anaerobic bacteria in the underlying sediment (Desulfobacterales and Desulfuromonadales (> 20%). Pond water in which E. prolifera-free was dominated by Rhodobacterales (58.19%), as well as aerobic and facultative anaerobic bacteria in the sediment. In addition, the ecological functions of other dominant bacteria, such as Candidatus Aquiluna, Microcella spp., and Marivita spp., should be studied in depth. Overall, massive growth of E. prolifera will have serious effects on bacterial communities, and, thus, it will have an important impact on the environment. The novel findings in this study will be valuable for understanding green tides.

ß-COP as a Component of Transport Vesicles for HDL Apolipoprotein-Mediated Cholesterol Exocytosis.

OBJECTIVE: HDL and its apolipoproteins protect against atherosclerotic disease partly by removing excess cholesterol from macrophage foam cells. But the underlying mechanisms of cholesterol clearance are still not well defined. We investigated roles of vesicle trafficking of coatomer ß-COP in delivering cholesterol to the cell surface during apoA-1 and apoE-mediated lipid efflux from fibroblasts and THP-1 macrophages. METHODS: shRNA knockout, confocal and electron microscopy and biochemical analysis were used to investigate the roles of ß-COP in apolipoprotein-mediated cholesterol efflux in fibroblasts and THP-1 macrophages. RESULTS: We showed that ß-COP knockdown by lentiviral shRNA resulted in reduced apoA-1-mediated cholesterol efflux, while increased cholesterol accumulation and formation of larger vesicles were observed in THP-1 macrophages by laser scanning confocal microscopy. Immunogold electron microscopy showed that ß-COP appeared on the membrane protrusion complexes and colocalized with apoA-1 or apoE during cholesterol efflux. This was associated with releasing heterogeneous sizes of small particles into the culture media of THP-1 macrophage. Western blotting also showed that apoA-1 promotes ß-COP translocation to the cell membrane and secretion into culture media, in which a total of 17 proteins were identified by proteomics. Moreover, ß-COP exclusively associated with human plasma HDL fractions. CONCLUSION: ApoA-1 and apoE promoted transport vesicles consisting of ß-COP and other candidate proteins to exocytose cholesterol, forming the protrusion complexes on cell surface, which were then released from the cell membrane as small particles to media.

Partial deletion of ROCK2 protects mice from high-fat diet-induced cardiac insulin resistance and contractile dysfunction.

Obesity is associated with cardiac insulin resistance and contractile dysfunction, which contribute to the development of heart failure. The RhoA-Rho kinase (ROCK) pathway has been reported to modulate insulin resistance, but whether it is implicated in obesity-induced cardiac dysfunction is not known. To test this, wild-type (WT) and ROCK2(+/-) mice were fed normal chow or a high-fat diet (HFD) for 17 wk. Whole body insulin resistance, determined by an insulin tolerance test, was observed in HFD-WT, but not HFD-ROCK2(+/-), mice. The echocardiographically determined myocardial performance index, a measure of global systolic and diastolic function, was significantly increased in HFD-WT mice, indicating a deterioration of cardiac function. However, no change in myocardial performance index was found in hearts from HFD-ROCK2(+/-) mice. Speckle-tracking-based strain echocardiography also revealed regional impairment in left ventricular wall motion in hearts from HFD-WT, but not HFD-ROCK2(+/-), mice. Activity of ROCK1 and ROCK2 was significantly increased in hearts from HFD-WT mice, and GLUT4 expression was significantly reduced. Insulin-induced phosphorylation of insulin receptor substrate (IRS) Tyr(612), Akt, and AS160 was also impaired in these hearts, while Ser(307) phosphorylation of IRS was increased. In contrast, the increase in ROCK2, but not ROCK1, activity was prevented in hearts from HFD-ROCK2(+/-) mice, and cardiac levels of TNFα were reduced. This was associated with normalization of IRS phosphorylation, downstream insulin signaling, and GLUT4 expression. These data suggest that increased activation of ROCK2 contributes to obesity-induced cardiac dysfunction and insulin resistance and that inhibition of ROCK2 may constitute a novel approach to treat this condition.

Methyl protodioscin increases ABCA1 expression and cholesterol efflux while inhibiting gene expressions for synthesis of cholesterol and triglycerides by suppressing SREBP transcription and microRNA 33a/b levels.

Sterol regulatory element-binding proteins (SREBPs) regulate homeostasis of LDL, HDL and triglycerides. This study was aimed to determine if inhibition of SREBPs by methyl protodioscin (MPD) regulates downstream gene and protein expressions of lipid metabolisms. In THP-1 macrophages, MPD increases levels of ABCA1 mRNA and protein in dose- and time-dependent manners, and apoA-1-mediated cholesterol efflux. The underlying mechanisms for the effects is that MPD inhibits the transcription of SREBP1c and SREBP2, and decreases levels of microRNA 33a/b hosted in the introns of SREBPs, which leads to reciprocally increase ABCA1 levels. In HepG2 cells, MPD shows the same effects as these observed in THP-1 macrophages. MPD also decreases the gene expressions of HMGCR, FAS and ACC for cholesterol and fatty acid synthesis. MPD further promotes LDL receptor through reducing the PCSK9 level. Collectively, the study demonstrates that MPD potentially increase HDL cholesterol while reducing LDL cholesterol and triglycerides.

Complex regulation of PKCß2 and PDK-1/AKT by ROCK2 in diabetic heart.

OBJECTIVES: The RhoA/ROCK pathway contributes to diabetic cardiomyopathy in part by promoting the sustained activation of PKCß2 but the details of their interaction are unclear. The purpose of this study was to investigate if over-activation of ROCK in the diabetic heart leads to direct phosphorylation and activation of PKCß2, and to determine if their interaction affects PDK-1/Akt signaling. METHODS: Regulation by ROCK of PKCß2 and related kinases was investigated by Western blotting and co-immunoprecipitation in whole hearts and isolated cardiomyocytes from 12 to 14-week diabetic rats. Direct ROCK2 phosphorylation of PKCß2 was examined in vitro. siRNA silencing was used to confirm role of ROCK2 in PKCß2 phosphorylation in vascular smooth muscle cells cultured in high glucose. Furthermore, the effect of ROCK inhibition on GLUT4 translocation was determined in isolated cardiomyocytes by confocal microscopy. RESULTS: Expression of ROCK2 and expression and phosphorylation of PKCß2 were increased in diabetic hearts. A physical interaction between the two kinases was demonstrated by reciprocal immunoprecipitation, while ROCK2 directly phosphorylated PKCß2 at T641 in vitro. ROCK2 siRNA in vascular smooth muscle cells or inhibition of ROCK in diabetic hearts reduced PKCß2 T641 phosphorylation, and this was associated with attenuation of PKCß2 activity. PKCß2 also formed a complex with PDK-1 and its target AKT, and ROCK inhibition resulted in upregulation of the phosphorylation of PDK-1 and AKT, and increased translocation of glucose transporter 4 (GLUT4) to the plasma membrane in diabetic hearts. CONCLUSION: This study demonstrates that over-activation of ROCK2 contributes to diabetic cardiomyopathy by multiple mechanisms, including direct phosphorylation and activation of PKCß2 and interference with the PDK-1-mediated phosphorylation and activation of AKT and translocation of GLUT4. This suggests that ROCK2 is a critical node in the development of diabetic cardiomyopathy and may be an effective target to improve cardiac function in diabetes.

Contribution of Rho kinase to blood pressure elevation and vasoconstrictor responsiveness in type 2 diabetic Goto-Kakizaki rats.

OBJECTIVES: The RhoA-Rho kinase (ROCK) pathway contributes to a number of diabetic complications including cardiomyopathy and nephropathy. In this study, we investigated whether it contributes to elevated blood pressure and vascular contractile dysfunction in type 2 diabetes. METHODS: Blood pressure was measured in Goto-Kakizaki rats, a nonobese model of type 2 diabetes, before and after treatment with the ROCK inhibitor fasudil. Vasoconstrictor responsiveness in the absence and presence of ROCK inhibitors as well as ROCK pathway activity was measured in isolated mesenteric resistance vessels from these animals. RESULTS: Blood pressure was elevated in diabetic rats compared with age-matched Wistar controls, and was normalized by treatment with fasudil. Contractile responses of mesenteric arteries from diabetic rats to phenylephrine and U-46619, as well as relaxant responses to acetylcholine, were unaltered. However, vasoconstrictor responses were more sensitive to ROCK inhibition with either Y-27632 or H-1152 than were responses of control arteries. No differences were found in expression of RhoA, ROCK1, or ROCK2 or in basal ROCK activity between arteries from control and diabetic rats. U-46619 produced a similar magnitude of increase in ROCK activity that was completely blocked by H-1152 in arteries from both groups of animals. CONCLUSION: These data suggest that ROCK contributes to the increase in blood pressure in type 2 diabetic Goto-Kakizaki rats, and that vasoconstrictor responses of small mesenteric arteries from these animals are more dependent on ROCK than are responses of control arteries.

Diabetes-induced increased oxidative stress in cardiomyocytes is sustained by a positive feedback loop involving Rho kinase and PKCß2.

We previously reported that acute inhibition of the RhoA/Rho kinase (ROCK) pathway normalized contractile function of diabetic rat hearts, but the underlying mechanism is unclear. Protein kinase C (PKC) ß(2) has been proposed to play a major role in diabetic cardiomyopathy at least in part by increasing oxidative stress. Further evidence suggests that PKC positively regulates RhoA expression through induction of inducible nitric oxide synthase (iNOS) in diabetes. However, in preliminary studies, we found that inhibition of ROCK itself reduced RhoA expression in diabetic hearts. We hypothesized that there is an interaction between RhoA/ROCK and PKCß(2) in the form of a positive feedback loop that sustains their activation and the production of reactive oxygen species (ROS). This was investigated in cardiomyocytes isolated from diabetic and control rat hearts, incubated with or without cytochalasin D or inhibitors of ROCK, RhoA, PKCß(2), or iNOS. Inhibition of RhoA and ROCK markedly attenuated the diabetes-induced increases in PKCß(2) activity and iNOS and RhoA expression in diabetic cardiomyocytes, while having no effect in control cells. Inhibition of PKCß(2) and iNOS also normalized RhoA expression and ROCK overactivation, whereas iNOS inhibition reversed the increase in PKCß(2) activity. Each of these treatments also normalized the diabetes-induced increase in production of ROS. Actin cytoskeleton disruption attenuated the increased expression and/or activity of all of these targets in diabetic cardiomyocytes. These data suggest that, in the diabetic heart, the RhoA/ROCK pathway contributes to contractile dysfunction at least in part by sustaining PKCß(2) activation and ROS production via a positive feedback loop that requires an intact cytoskeleton.

Selective inhibition of protein kinase C beta(2) attenuates inducible nitric oxide synthase-mediated cardiovascular abnormalities in streptozotocin-induced diabetic rats.

OBJECTIVE: Impaired cardiovascular function in diabetes is partially attributed to pathological overexpression of inducible nitric oxide synthase (iNOS) in cardiovascular tissues. We examined whether the hyperglycemia-induced increased expression of iNOS is protein kinase C-beta(2) (PKCbeta(2)) dependent and whether selective inhibition of PKCbeta reduces iNOS expression and corrects abnormal hemodynamic function in streptozotocin (STZ)-induced diabetic rats. RESEARCH DESIGN AND METHODS: Cardiomyocytes and aortic vascular smooth muscle cells (VSMC) from nondiabetic rats were cultured in low (5.5 mmol/l) or high (25 mmol/l) glucose or mannitol (19.5 mmol/l mannitol + 5.5 mmol/l glucose) conditions in the presence of a selective PKCbeta inhibitor, LY333531 (20 nmol/l). Further, the in vivo effects of PKCbeta inhibition on iNOS-mediated cardiovascular abnormalities were tested in STZ-induced diabetic rats. RESULTS: Exposure of cardiomyocytes to high glucose activated PKCbeta(2) and increased iNOS expression that was prevented by LY333531. Similarly, treatment of VSMC with LY333531 prevented high glucose-induced activation of nuclear factor kappaB, extracellular signal-related kinase, and iNOS overexpression. Suppression of PKCbeta(2) expression by small interference RNA decreased high-glucose-induced nuclear factor kappaB and extracellular signal-related kinase activation and iNOS expression in VSMC. Administration of LY333531 (1 mg/kg/day) decreased iNOS expression and formation of peroxynitrite in the heart and superior mesenteric arteries and corrected the cardiovascular abnormalities in STZ-induced diabetic rats, an action that was also observed with a selective iNOS inhibitor, L-NIL. CONCLUSIONS: Collectively, these results suggest that inhibition of PKCbeta(2) may be a useful approach for correcting abnormal hemodynamics in diabetes by preventing iNOS mediated nitrosative stress.