活血化痰通络方早期治疗风痰瘀阻证急性小动脉闭塞型脑梗死的临床研究

目的 观察活血化痰通络方早期治疗风痰瘀阻证急性小动脉闭塞型脑梗死的临床疗效.方法 将2018年8月1日—2019年9月30日在湖北省中西医结合医院神经内科住院的240例风痰瘀阻证急性小动脉闭塞型脑梗死患者随机分成治疗组和对照组,每组120例.对照组给予常规西药治疗,治疗组在西药治疗基础上给予活血化痰通络方治疗2周.观察...     

Nitric oxide donor-induced increase in permeability of the blood–brain barrier

The goal of the present study was to determine the effect of nitric oxide (NO) donors on the permeability of the blood–brain barrier in vivo. We examined the pial microcirculation in rats using intravital fluorescence microscopy. Permeability of the blood–brain barrier was quantitated by calculating the clearance of fluorescent-labeled dextran (M_w=10 000 Da; FITC–dextran-10K) during suffusion with vehicle, S-nitroso-N-acetylpenicillamine (SNAP; 100 μM) and 3-morpholinosydnonimin (SIN-1; 100 μM). In addition, we examined changes in arteriolar diameter during suffusion with vehicle, SNAP and SIN-1. During suffusion with vehicle, clearance of FITC–dextran-10K from pial vessels and diameter of pial arterioles remained relatively constant during the experimental period. In contrast, suffusion with SNAP or SIN-1 markedly increased clearance of FITC–dextran-10K from the cerebral microcirculation and produced a rapid, sustained dilatation of pial arterioles. Thus, NO donors increase the permeability of the blood–brain barrier and produce pronounced dilatation of cerebral arterioles. In light of evidence suggesting that NO donors may produce their effect by the simultaneous release of NO and superoxide anion to form peroxynitrite, we elected to examine the role of superoxide anion in increases in permeability of the blood–brain barrier in response to SNAP and SIN-1. We found that suffusion with tiron (1 mM) did not alter basal permeability of the blood–brain barrier, but significantly inhibited increases in permeability of the blood–brain barrier in response to SNAP and SIN-1. In addition, tiron did not alter baseline diameter of cerebral arterioles, or SNAP- and SIN-1-induced cerebrovasodilatation. The findings of the present study suggest that NO donors produce an increase in permeability of the blood–brain barrier which appears to be related to the presence of NO and superoxide anion, to presumably form peroxynitrite. We suggest that increases in NO formation observed during brain trauma may contribute to disruption of the blood–brain barrier.     

Site‐specific absence of microfibrillar‐associated protein 4 (MFAP4) from the internal elastic membrane of arterioles in the rheumatoid arthritis synovial membrane: an immunohistochemical study in patients with advanced rheumatoid arthritis versus osteoarthritis

Microfibrillar‐associated protein 4 (MFAP4) is a non‐structural matrix protein with cell regulatory activities and a potential as seromarker for fibrosis. We aimed to study the occurrence of MFAP4 in the synovial membrane from patients with rheumatoid arthritis (RA) vs osteoarthritis (OA). Formaldehyde‐fixed synovial tissue sections, from patients with RA (N = 6) and OA (N = 6) undergoing total hip arthroplasty, were deparaffinized and immunostained with monoclonal antibodies against MFAP4. Elastin was detected using ElastiKit. MFAP4 in serum (sMFAP4) and synovial fluid was measured by an immunoassay. MFAP4 was present in synovial biopsies from both RA and OA patients, particularly prominent in deep arterioles where it colocalized with elastin. Notably however, MFAP4 was absent from the internal elastic lamina in RA arterioles irrespective of disease duration and synovitis activity, while present although with irregular staining patterns in OA specimens. sMFAP4 was increased in RA and OA serum vs healthy controls: median (interquartile range) 29.8 (25.3–39.1) and 25.5 U/L (18.1–43.3) vs 17.7 U/L (13.7–21.2), p = 0.006 and p = 0.02, respectively The concentration of synovial fluid was lower than in serum in both RA and OA. These findings may suggest that MFAP4 is involved in adaptive vessel wall remodeling associated with chronic joint disease.     

INCREASED NO-MEDIATED AND REDUCED TxA2-DEPENDENT RESPONSES IN SKELETAL MUSCLE ARTERIOLES IN PREGNANCY

The contribution of skeletal muscle microvessels to pregnancy-induced decrease in peripheral vascular resistance and its underlying mechanisms are not fully understood. We aimed to test the hypothesis that pregnancy enhances arteriolar dilation and reduces constriction by increasing NO-mediation and decreasing reactivity to TxA₂. Thus, changes in diameter of isolated, pressurized gracilis muscle arterioles (d: ～180 μm) of non-pregnant (NP) and pregnant (P) rabbits to vasoactive agents were measured by videomicroscopy. Acetylcholine (ACh) elicited significantly greater dilations in P than in NP arterioles that could be inhibited by l-NAME, a NO synthase blocker. Dilations to the NO donor SNP did not differ between P and NP arterioles. Constrictions to norepinephrine and the TxA₂ receptor agonist U46619 were significantly attenuated in P as compared to NP arterioles. l-NAME increased norepinephrine-induced arteriolar constrictions eliminating the difference between responses of NP and P arterioles. l-NAME enhanced constrictions to U46619 in P and NP arterioles, but the constrictions were still greater in NP vessels. The number of vascular TxA₂ receptors—characterized by the TxA₂ analog [¹²⁵I]-BOP in aortic membrane preparations—was significantly less in P as compared to NP rabbits (NP: 284±83, P: 62±14 fmol/mg protein, p<0.01). Thus, pregnancy up-regulates endothelial NO- and down regulates TxA₂-mediation of responses of skeletal muscle arterioles. These changes in the local regulation of microvascular tone are likely to favor a dilated state of skeletal muscle arterioles, which may contribute to the decreased peripheral vascular resistance during normal pregnancy.     

Ca2+ sparks promote myogenic tone in retinal arterioles

Background and Purpose

Ca²⁺ imaging reveals subcellular Ca²⁺ sparks and global Ca²⁺ waves/oscillations in vascular smooth muscle. It is well established that Ca²⁺ sparks can relax arteries, but we have previously reported that sparks can summate to generate Ca²⁺ waves/oscillations in unpressurized retinal arterioles, leading to constriction. We have extended these studies to test the functional significance of Ca²⁺ sparks in the generation of myogenic tone in pressurized arterioles.

Experimental Approach

Isolated retinal arterioles (25–40 μm external diameter) were pressurized to 70 mmHg, leading to active constriction. Ca²⁺ signals were imaged from arteriolar smooth muscle in the same vessels using Fluo4 and confocal laser microscopy.

Key Results

Tone development was associated with an increased frequency of Ca²⁺ sparks and oscillations. Vasomotion was observed in 40% of arterioles and was associated with synchronization of Ca²⁺ oscillations, quantifiable as an increased cross-correlation coefficient. Inhibition of Ca²⁺ sparks with ryanodine, tetracaine, cyclopiazonic acid or nimodipine, or following removal of extracellular Ca²⁺, resulted in arteriolar relaxation. Cyclopiazonic acid-induced dilatation was associated with decreased Ca²⁺ sparks and oscillations but with a sustained rise in the mean global cytoplasmic [Ca²⁺] ([Ca²⁺]_c), as measured using Fura2 and microfluorimetry.

Conclusions and Implications

This study provides direct evidence that Ca²⁺ sparks can play an excitatory role in pressurized arterioles, promoting myogenic tone. This contrasts with the generally accepted model in which sparks promote relaxation of vascular smooth muscle. Changes in vessel tone in the presence of cyclopiazonic acid correlated more closely with changes in spark and oscillation frequency than global [Ca²⁺]_c, underlining the importance of frequency-modulated signalling in vascular smooth muscle.     

The adverse pial arteriolar and axonal consequences of traumatic brain injury complicated by hypoxia and their therapeutic modulation with hypothermia in rat

This study examined the effect of posttraumatic hypoxia on cerebral vascular responsivity and axonal damage, while also exploring hypothermia''s potential to attenuate these responses. Rats were subjected to impact acceleration injury (IAI) and equipped with cranial windows to assess vascular reactivity to topical acetylcholine, with postmortem analyses using antibodies to amyloid precursor protein to assess axonal damage. Animals were subjected to hypoxia alone, IAI and hypoxia, IAI and hypoxia before induction of moderate hypothermia (33°C), IAI and hypoxia induced during hypothermic intervention, and IAI and hypoxia initiated after hypothermia. Hypoxia alone had no impact on vascular reactivity or axonal damage. Acceleration injury and posttraumatic hypoxia resulted in dramatic axonal damage and altered vascular reactivity. When IAI and hypoxia were followed by hypothermic intervention, no axonal or vascular protection ensued. However, when IAI was followed by hypoxia induced during hypothermia, axonal and vascular protection followed. When this same hypoxic insult followed the use of hypothermia, no benefit ensued. These studies show that early hypoxia and delayed hypoxia exert damaging axonal and vascular consequences. Although this damage is attenuated by hypothermia, this follows only when hypoxia occurs during hypothermia, with no benefit found if the hypoxic insult proceeds or follows hypothermia.     

The distribution of cerebrovascular amyloid in Alzheimer’s disease varies with <Emphasis Type="Italic">ApoE</Emphasis> genotype

We performed a comparative study to assess cerebral amyloid angiopathy and ApoE genotype in cases of Alzheimer’s disease (AD). Ten ApoE 3,3 and ten ApoE 4,4 AD brains, as well as ten normal control brains, were selected after matching for age, sex, and duration of disease. Sections of middle frontal and inferior parietal cortex including white matter sections were stained with an antibody against amyloid beta (Aβ), and extensive analysis of arteriolar Aβ deposition was performed using digital image analysis. Quantification of the staining revealed a larger cross-section of arteriolar walls occupied by Aβ in ApoE 4,4 and ApoE 3,3 AD subjects compared to controls. Our results show Aβ deposition in gray matter and white matter arterioles was predominantly found in ApoE 4,4 brains and, overall, Aβ deposition was greatest in these cases. This observation implies that there is greater vascular amyloid deposition (particularly in the white matter arterioles) in ApoE 4,4 AD individuals compared to ApoE 3,3 AD. These observations may give insight into the etiology behind the increased risk for AD associated with the ApoE-ε4 allele and the pathogenesis of vascular Aβ deposition.This study was supported by the National Institutes of Health NIA P50 AG05128 and P30 AG028377.     

Hypertension Decreases Small Arteriole Responses to Acetylcholine in Skeletal Muscle

Television microscopy was used to quantitate in vivo the responses of skeletal muscle small arterioles to acetylcholine. Five groups of rats were used: normotensive and one (1K1C)- and two (2K1C)- kidney one clip renovascular hypertensive Sprague-Dawley rats (SDR), as well as WKY normotensive and spontaneously hypertensive (SHR) rats. Third-order arterioles dilated to acetylcholine with an EC₅₀ of 3 × 10^?7 M in SDR and 10_?6 M in WKY animals. In contrast, the concentration-response curve to acetylcholine was shifted to the right (less reactive) by 100 fold in the 1K1C- and by 1000 fold in the 2K1C-hypertensives. The dose-responsive curve to acetylcholine was shifted 10-fold to the right in the SHR's compared to the WKY's. Because acetylcholine acts through endothelium-dependent mechanisms and because maximal vasodilation could be induced by an endothelium-independent vasodilator, Na-nitroprusside, in all but the 2K1C-group, we conclude that different forms of hypertension interfere to a variable degree with endothelium-dependent vasodilator mechanisms in the skeletal muscle microcirculation.     

重度子痫前期子宫小动脉平滑肌细胞大电导钙激活钾通道的改变

目的研究重度子痫前期患者子宫小动脉平滑肌大电导钙激活钾通道的改变。方法选取2012年6月至2013年3月在泸州医学院附属医院产科住院分娩的20例患者的临床资料,其中临床诊断为重度子痫前期(severe preeclampsia,SPE)且无其它并发症和合并症进行剖宫产手术10例为SPE组;同期无产科并发症和合并症的足月孕产妇因其他原因行剖宫产手术终止妊娠者10例为正常晚孕(normal late pregnancy,NLP)组。取行剖宫产手术患者的子宫小动脉,采用急性酶分离法分离出小动脉平滑肌细胞,按平滑肌细胞的来源分为重度子痫前期组和正常足月妊娠组,采用单通道膜片钳技术记录子宫小动脉平滑肌细胞BKCa通道电流。结果妊娠期子宫小动脉平滑肌细胞BKCa通道单通道电流能被Ib TX通道特异阻断剂阻断,具有电压和钙离子浓度依赖性;在细胞贴附式膜片下,重度子痫前期组与正常足月妊娠组相比,BKCa通道开放概率减少(P0.01),电流幅值减小(P0.01)、平均开放时间减少(P0.01)、平均关闭时间无明显变化。结论重度子痫前期患者子宫小动脉平滑肌细胞BKCa通道活性降低。