Scanning and transmission electron microscopy of venous sphincters in the rat lung

The rat pulmonary microvasculature was studied using scanning and transmission electron microscopy of vascular corrosion casts and tissue sections. Special emphasis was placed on small pulmonary venous vessels. The shape of vascular casts was analyzed and interpreted concerning the wall composition of corresponding vessels studied in tissue sections. On the casts of pulmonary venules and small pulmonary veins, narrow or wider annular constrictions were regularly observed. Within these constrictions, marks of circularly running grooves were seen as an additional structural detail, which obviously mimic impressions of single or grouped smooth muscle cells. The depth of the constrictions varies; it may be more or less pronounced, occasionally narrowing down the luminal diameter to approximately 50%. These constrictions are caused by muscular sphincters. In tissue sections of small pulmonary veins, sphincter regions were identified as abruptly appearing single or grouped true smooth muscle cells. Smooth muscle cells may be arranged side by side in a group or bundle or even staked in two or three layers. Between the sphincter regions, the venous wall consists merely of endothelium and an accompanying connective tissue layer. The smooth muscle cells of a sphincter are regularly positioned between endothelial layer and elastic lamina. The smooth muscle cells next to the endothelium form myoendothelial junctions. Autonomic nerves near the sphincters were never seen. The venous sphincters described are suggested to be effective devices involved in blood flow regulation. Blood-borne substances or local tissue hormones might govern sphincter function. © 1992 Wiley-Liss, Inc.     

Vascular networks of the nucleus lentiformis

Summary The nucleus lentiformis vascular networks were studied in 30 brains by injecting the vascular system with gelatinous Indian ink. The nucleus lentiformis is divided into a medial part, the globus pallidus, and a lateral part, the putamen. These two parts differ completely from one another in their embryology, structure and functions. For these reasons, each part presents a specific vascular network. The putaminal network is dense and shows many similarities with the cerebral cortex vascular network; the pallidal one is simpler and less dense. These two vascular networks are located close to each other without overlapping. Their specificity may be in relation with the histological structure, with the morphogenetic evolution or with the functional activity of both nuclei to which they provide the vascularization.

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Les réseaux vascularies du noyau lenticulaire

Résumé L'étude des réseaux vasculaires du noyau lenticulaire (NL) est réalisée sur 30 cerveaux dont le système vasculaire a été injecté à l'encre de Chine gélosée. Le NL est constitué par deux parties, le putamen (néostriatum) et le globus pallidus (paléo-striatum), totalement différentes sur les plans morphologique, embryologique et fonctionnel. Chacune de ces parties possède un réseau vasculaire spécifique et caractéristique. Les deux réseaux se côtoient sans se chevaucher. Le réseau vasculaire putaminal est dense et présente de nombreuses similitudes avec le réseau vasculaire du cortex cérébral. Le réseau vasculaire pallidal se caractérise par sa simplicité et sa moindre densité. Leur spécificité peut être en rapport avec la structure histologique, l'évolution morphogénétique et avec l'activité fonctionnelle des noyaux dont ils assurent l'irrigation.

     

Capillaries in aging rat olfactory bulb: A quantitative light and electron microscopic analysis

Olfactory bulbs from Charles River (Crl) rats from 3 to 36 months have been examined with light and electron microscopy. Total capillary length, surface, and volume, as well as number of endothelial cells, increases during the twofold increase in olfactory bulb volume from 3 to 18 months, but the relative density of these parameters shows no change during this time; from 18 to 36 months when neuronal cell body and dendrites are decreasing markedly in size, the relative density of capillaries shows only a modest decrease. Capillary lumen size and capillary wall thickness remain the same throughout life, but basal lamina thickness doubles from 3 to 24 months and then remains constant from 24 to 36 months. The incidence of several unusual ultrastructural features of the outer capillary basal lamina has been shown to increase with age.     

Radiation-induced heart disease in rats

After local irradiation of the rat heart with X ray doses of over 10 Gy (single dose), animals developed symptoms of radiation-induced heart disease, which at higher doses would lead to fatal cardiac failure. The LD 50 at 1 year was between 15 Gy and 20 Gy. The pericardium and epicardium responded to irradiation with exudative pericarditis after 4 months. Focal myocardial damage was secondary to progressive capillary damage.     

The impact of experimental diabetes mellitus in rats on glomerular capillary number and sizes

Summary The structural counterpart of the increased glomerular filtration found in acute diabetes mellitus and experimental diabetes has been ascribed to the increased glomerular filtration surface. Using modern design-based stereological methods and light microscopy on perfusionfixed rat kidneys the average total surface area of capillaries per glomerulus in control rats was 291±42 10^–3 mm² (±SD) increasing to 383±55 10^–3 mm² in 10-day-diabetic rats. There was a further increase to 469±70 10^–3 mm² in 50-day-diabetic rats. The average total length of capillaries per glomerulus increased from 12.5±2.2 mm in the control rats to 16.9±2.4 mm in the 10-day-diabetic rats whereas the further increase to 19.4±3.0 mm in the 50-day-diabetic rats failed to reach statistical significance. The average number of topologically defined capillaries per glomerulus increased from 215±29 in the control rats to 260±45 and 316±29 in the 10-day-diabetic and 50-day-diabetic rats, respectively. The results showed just a slight increase in the mean length of a capillary from 58.1±6.2 m in the control rats to 65.6±2.6 m in the 10-day-diabetic rats after which it normalized in the 50-day-diabetic rats to 61.3±3.6 m. The geometric factor or resistance in Poiseuille's law did not differ between the three groups, neither did the diameter of the capillaries, nor the number of glomeruli. The implications of the formation of capillaries in renal glomeruli are discussed and it is concluded that glomerular capillaries in experimental diabetes grow mainly by the formation of new capillaries.     

Interstitial Capillary in Normal and in Transplanted Kidneys: An Ultrastructural Study

Knowledge about the normal structure and pathology of interstitial capillary is limited. Splitting and multilayering of the basal membrane (BM), as a marker of chronic rejection, has been published in association with transplant glomerulopathy. The authors investigated the ultrastructural features of the interstitial capillary basal membrane in normal (15 biopsies) and in transplanted kidneys (27 biopsies from 21 patients), expressing transplant glomerulopathy (8 biopsies from 6 patients), acute tubulo-interstitial rejection (9 biopsies from 6 patients), and recurrent or de novo glomerulonephritis (10 biopsies from 8 patients). All biopsies were fixed in 1%OsO 4, embedded in Epon, and examined by electron microscope. Measurements of the interstitial capillary BM were made. The BM of interstitial capillary of intact kidney was a homogenous continuous structure, 88 nm in width on average. Thickening with diffuse multilayering of BM was most intensive in patients with transplant glomerulopathy, and much less intensive in patients with acute tubulointerstitial rejection and in patients with recurrent or de novo glomerulonephritis. These findings may provide the first information about the morphology of the normal basal lamina of interstitial capillary and support the diagnostic value of interstitial capillary changes in chronic rejection.     

抗血管内皮生长因子药物治疗对视网膜静脉阻塞黄斑水肿患者视网膜毛细血管影响的研究现状

玻璃体腔注射抗VEGF药物是目前治疗视网膜静脉阻塞(RVO)黄斑水肿的主要手段,其能明显抑制新生血管,减轻水肿,提高患者视力。但VEGF是血管内皮细胞的存活因子,其是否会导致视网膜缺血进展以及是否对视网膜毛细血管产生影响值得临床关注。就目前来看,大多学者认为,从拱环形态改变以及浅层、深层视网膜毛细血管层量化黄斑中心凹无血管区面积、视网膜无灌注区大小及黄斑区视网膜血流密度等方面观察,抗VEGF药物治疗RVO黄斑水肿并不会加重视网膜毛细血管的闭塞。并且,这些指标的变化可能与患者需要治疗的次数、视力预后等有一定的关系。今后随着OCT血管成像的逐渐普及以及抗VEGF药物治疗次数和时间的延长,期待更大样本、更长随访时间的研究深入分析抗VEGF药物治疗对RVO黄斑水肿患者视网膜毛细血管的确切影响。     

Association of crossing capillaries in the finger nailfold with diabetic retinopathy in type 2 diabetes mellitus

Aims/IntroductionCrossing capillaries in the finger nailfold might potentially be a novel diabetic retinopathy (DR) biomarker that could be assessed non‐invasively in the clinical setting. However, the association between crossing capillaries and DR is controversial. This study aimed to investigate the association between the percentage of crossing capillaries in the finger nailfold and DR in patients with type 2 diabetes mellitus.Materials and MethodsThis cross‐sectional study enrolled 108 type 2 diabetes mellitus patients (aged 40–75 years) who visited the outpatient diabetic clinic at Osaka University Hospital, Osaka, Japan, between May and October 2019. Capillary morphology was assessed using nailfold capillaroscopy based on the simple capillaroscopic definitions of the European League Against Rheumatism Study Group. Details of DR and other laboratory data were obtained from medical records. The association between the tertile of the percentage of the crossing capillary and DR was analyzed using multivariable logistic regression.ResultsAfter adjusting for age, sex, diabetes duration, glycated hemoglobin, systolic blood pressure, body mass index, and use of renin–angiotensin system inhibitor and antihyperlipidemic medication, the percentage of crossing capillaries was significantly associated with DR (multivariable‐adjusted odds ratios for increasing tertiles of the percentage of crossing capillary: 1 [reference], 2.05 [95% confidence interval 0.53–7.94], and 4.33 [95% confidence interval 1.16–16.21]; P‐trend = 0.028).ConclusionsA higher percentage of crossing capillaries in the nailfold was associated with a higher risk of DR, independent of traditional risk and inhibiting factors, in patients with type 2 diabetes mellitus.     

In Vitro Analysis of Human Periodontal Microvascular Endothelial Cells

Background: Endothelial cells (ECs) participate in key aspects of vascular biology, such as maintenance of capillary permeability, initiation of coagulation, and regulation of inflammation. According to previous reports, ECs have revealed highly specific characteristics depending on the organs and tissues. However, some reports have described the characteristics of the capillaries formed by human periodontal ECs. Therefore, the aim of the present study is to examine the functional characteristics of the periodontal microvascular ECs in vitro. Methods: Human periodontal ligament‐endothelial cells (HPDL‐ECs) and human gingiva‐endothelial cells (HG‐ECs) were isolated by immunoprecipitation with magnetic beads conjugated to a monoclonal anti‐CD31 antibody. The isolated HPDL‐ECs and HG‐ECs were characterized to definitively demonstrate that these cell cultures represented pure ECs. Human umbilical‐vein ECs and human dermal microvascular ECs were used for comparison. These cells were compared according to the proliferation potential, the formation of capillary‐like tubes, the transendothelial electric resistance (TEER), and the expression of tight junction proteins. Results: HPDL‐ECs and HG‐ECs with characteristic cobblestone monolayer morphology were obtained, as determined by light microscopy at confluence. Furthermore, the HPDL‐ECs and HG‐ECs expressed the EC markers platelet endothelial cell adhesion molecule‐1 (also known as CD31), von Willebrand factor, and Ulex europaeus agglutinin 1, and the cells stained strongly positive for CD31 and CD309. In addition, the HPDL‐ECs and HG‐ECs were observed to form capillary‐like tubes, and they demonstrated uptake of acetylated low‐density lipoprotein. Functional analyses of the HPDL‐ECs and HG‐ECs showed that, compared to the control cells, tube formation persisted for only a brief period of time, and TEER was substantially reduced at confluence. Furthermore, the cells exhibited delocalization of zonula occludens‐1 and occludin at cell–cell contact sites. Conclusions: The present results provide new evidence that HPDL‐ECs and HG‐ECs have characteristics of fenestrated capillaries. Therefore, capillaries in human periodontal tissues have functional characteristics of fenestrated capillaries, which might be related to the onset and the progression of systemic diseases and inflammation.     

普通窄带成像内镜对结直肠增生性息肉和腺瘤的鉴别诊断价值

目的 分析普通窄带成像(NBI)内镜下结直肠增生性息肉与腺瘤腺管及微血管特征的差异,评价NBI的鉴别诊断价值.方法 将普通内镜下诊断结直肠息肉、病理检查证实为增生性息肉或腺瘤者纳入研究并进行NBI内镜检查.将腺管形态参照改良的工藤分型法分为A型和B型.将微血管形态分为3型,无微血管判为Ⅰ型,微血管沿腺管开口排列、粗细均匀判为Ⅱ型,微血管粗细不均、排列紊乱判为Ⅲ型.比较增生性息肉和腺瘤NBI图像中腺管形态和微血管形态特征的差异,同时对无放大NBI图像观察者间的一致性进行评价.结果 共87例患者的107个息肉(腺瘤73个、增生性息肉34个)进行普通NBI内镜检查.腺瘤组息肉最大径和表面分叶者比例明显高于增生性息肉组(P值分别=0.0023和0.0047).腺瘤组中B型腺管形态[86.3％(63/73)]及Ⅱ或Ⅲ型微血管形态[82.2％(60/73)]者较多.以B型腺管形态、Ⅱ型或Ⅲ型微血管中任一特征诊断腺瘤的敏感度、特异度、准确率分别为97.3％、82.4％、92.5％.以B型腺管形态联合Ⅱ型或Ⅲ型微血管诊断腺瘤的敏感度、特异度、准确率分别为71.2％、91.2％、77.6％.观察者间一致性评价平均Kappa值为0.761.结论 普通NBI内镜下结直肠腺瘤和增生性息肉的微血管特征和腺管特征存在差异,依据以上两方面可在NBI内镜下实时初步鉴别腺瘤和增生性息肉.