Density of high endothelial venules and PDL-1 expression: relationship with tumor-infiltrating lymphocytes in primary cutaneous melanomas

Studies have highlighted melanoma immunogenicity, and the prognostic importance of tumor infiltrating lymphocytes (TILs) and mechanisms of tumor immune evasion, such as hyperexpression of programmed cell death ligand 1 (PDL-1). High endothelial venules (HEV) are specialized blood vessels that can facilitate the lymphocytes migration to the tumor. Here we evaluate the association of HEV density and PDL-1 expression in primary cutaneous melanomas with the presence and degree of TILs and with other clinicopathological variables (age, sex, tumor location, melanoma histological type, Breslow thickness, ulceration, regression signs, mitotic index). HEV density and PDL-1 expression were assessed immunohistochemically in 78 melanoma cases, using a specific antibody, and were detected in 59% and 76% of these, respectively. Positive associations were identified between HEV density and PDL-1 expression with the presence and degree of lymphocytic infiltration, melanoma histological type and ulceration presence. No correlation was found between HEV density and PDL-1 expression. Our findings confirm the HEV role in the recruitment and facilitation of lymphocyte transport in cutaneous melanomas, where HEV density is strongly associated with the degree of TILs. Additionally, PDL-1 hyperexpression suggests a possible mechanism of tumor immune evasion, which may lead to inactivation and reduction of the tumor lymphocytes number.

RETINAL MICROVASCULAR CHANGES AND RISK OF CORONARY HEART DISEASE: A Systematic Review and Meta-Analysis

PURPOSE

To quantify associations between various retinal microvascular changes and the risk of the development of coronary heart disease (CHD).

METHODS

PubMed, Embase, Web of Science, and Cochrane Library databases were searched for cohort studies on the association between retinal microvascular changes and incident CHD up to July 31, 2023. The summary risk estimates were estimated using the random-effects model. Subgroup and sensitivity analyses were performed to investigate the potential source of heterogeneity.

RESULTS

The authors identified 21 studies that met the inclusion criteria of this meta-analysis through database searching. This study yielded significant associations between retinal microvascular changes, including arteriolar narrowing, venular widening, vessel occlusion, and other retinal vascular signs, and the risk of CHD, with pooled adjusted hazard ratios of 1.20 (95% confidence interval: 1.13-1.27). In sex- and age-stratified analyses, retinal microvascular changes were associated with a greater risk of developing CHD in female patients and younger adults.

CONCLUSION

A range of retinal microvascular changes was associated with the risk of CHD, particularly in female patients and younger ages. The results of this study support the concept that retinal microvascular abnormalities may be markers for future CHD. Noninvasive retinal microvascular assessments may be helpful in screening patients with increased CHD risk.

High endothelial venule is a prognostic immune-related biomarker in patients with resected intrahepatic cholangiocarcinoma

Having been reported to be a crucial prognostic factor in solid tumours, the role of high endothelial venule (HEV) in intrahepatic cholangiocarcinoma (ICC) remains unclear, however. The data of ICC and healthy individuals were downloaded from the Gene Expression Omnibus (GEO), and The Cancer Genome Atlas (TCGA) databases. Meanwhile, a cutting-edge ICC high-resolution spatial transcriptome was also acquired before these data were comprehensively analysed using bioinformatics approaches. Moreover, 95 individuals with ICC who had undergone resection surgery were enrolled in this study to investigate the relationship between HEV and tumour microenvironment (TME) applying immunohistochemistry and multiple immunofluorescence techniques. The high-HEV subtype contains rich immune infiltrates including tertiary lymphoid structure (TLS), CD8+ T cells, and CD20+ B cells. Furthermore, HEV and TLS exhibited a strong relationship of spatial colocalization. Correlated with improved prognostic outcomes in ICC, the high-HEV subtype could be an independent prognostic indicator for individuals with ICC. This study revealed the association of HEV with immune function and observed a strong spatial colocalization correlation between HEV and TLS. Moreover, correlated with immunotherapeutic response, HEV could improve prognostic outcomes, which may be a potential indicator of immunotherapy pathology in ICC.

Diffuse generalized venulitis as the primary pathology of Behçet's disease: A comprehensive magnetic resonance venography study

OBJECTIVE

Behçet's Disease (BD) is a chronic multisystem vasculitis that manifests with destructive inflammation affecting the eyes, central nervous system, and blood vessels. The pathology of vein involvement in BD is poorly characterized. Magnetic resonance (MR) venography gives more comprehensive information about deep veins and adjacent tissues. In this study, we aimed to characterize vein involvement and evaluate the diagnostic utility of MR venography in BD.

METHODS

Sixty-five BD patients who fulfilled the International Study Group (ISG) criteria and 20 healthy control subjects were enrolled. Inferior vena cava (IVC), common iliac veins (CIV), external (EIV) and internal iliac veins (IVV), common femoral veins (CFV), femoral veins (FV), and greater saphenous veins (GSV) of BD patients and healthy controls were evaluated with MR venography and ultrasonography for the presence pathologic features, luminal thrombi, vessel wall changes, and perivascular abnormalities.

RESULTS

33 vascular and 32 non-vascular BD patients (mean age 39.3 ± 11.3 years and 48 [73.8%] male) were enrolled. MR venography revealed diffuse concentric thickening of the walls of IVC, CIV, EIV, IIV, CFV, FV, and GSV in BD (healthy controls vs. BD p<0.05 for all vein segments). MR venography provided additional information about veins and perivascular tissues like contrast enhancement, enlarged lymph nodes, and seminal vesicle vascularization, which were remarkably more frequent in vascular BD than non-vascular BD and healthy controls.

CONCLUSION

The results of our study suggest that the involvement of the venous system is diffuse and generalized in BD, and demonstration of venulitis might help diagnose the disease.

Arteriolosclerosis differs from venular collagenosis in relation to cerebrovascular parenchymal damages: an autopsy-based study

BACKGROUND AND PURPOSE

Cerebrovascular parenchymal damage is prevalent in ageing brains; however, its vascular aetiology has not been fully elucidated. In addition to the underlying role of sclerotic arterioles, the correlation between collagenised venules has not been clarified. Here, we aimed to investigate the associations between microvascular injuries, including arteriolosclerosis and venular collagenosis, and related parenchymal damages in ageing brains, to investigate the underlying correlations.

METHODS

We evaluated arteriolosclerosis and venular collagenosis in 7 regions from 27 autopsy cases with no history of stroke or brain tumour. The correlations between the ratio of arteriolosclerosis, venular collagenosis and the severity of cerebrovascular parenchymal damage, including lacunes, microinfarcts, myelin loss, and parenchymal and perivascular haemosiderin deposits, were assessed.

RESULTS

Arteriolosclerosis and venular collagenosis became more evident with age. Arteriolosclerosis was associated with lacunes (p=0.004) and brain parenchymal haemosiderin deposits in the superior frontal cortex (p=0.024) but not with leukoaraiosis severity. Venular collagenosis was not associated with the number of lacunes or haemosiderin, while white matter generally became paler with severe venular collagenosis in the periventricular (β=-0.430, p=0.028) and deep white matter (β=-0.437, p=0.025).

CONCLUSION

Our findings imply an important role for venular lesions in relation to microvessel-related parenchymal damage which is different from that for arteriolosclerosis. Different underlying mechanisms of both cerebral arterioles and venules require further investigation.

High endothelial venules in cancer: Regulation, function, and therapeutic implication

The lack of sufficient intratumoral CD8⁺ T lymphocytes is a significant obstacle to effective immunotherapy in cancer. High endothelial venules (HEVs) are organ-specific and specialized postcapillary venules uniquely poised to facilitate the transmigration of lymphocytes to lymph nodes (LNs) and other secondary lymphoid organs (SLOs). HEVs can also form in human and murine cancer (tumor HEVs [TU-HEVs]) and contribute to the generation of diffuse T cell-enriched aggregates or tertiary lymphoid structures (TLSs), which are commonly associated with a good prognosis. Thus, therapeutic induction of TU-HEVs may provide attractive avenues to induce and sustain the efficacy of immunotherapies by overcoming the major restriction of T cell exclusion from the tumor microenvironment. In this review, we provide current insight into the commonalities and discrepancies of HEV formation and regulation in LNs and tumors and discuss the specific function and significance of TU-HEVs in eliciting, predicting, and aiding anti-tumoral immunity.

Cancer immunotherapies transition endothelial cells into HEVs that generate TCF1+ T lymphocyte niches through a feed-forward loop

The lack of T cell infiltrates is a major obstacle to effective immunotherapy in cancer. Conversely, the formation of tumor-associated tertiary-lymphoid-like structures (TA-TLLSs), which are the local site of humoral and cellular immune responses against cancers, is associated with good prognosis, and they have recently been detected in immune checkpoint blockade (ICB)-responding patients. However, how these lymphoid aggregates develop remains poorly understood. By employing single-cell transcriptomics, endothelial fate mapping, and functional multiplex immune profiling, we demonstrate that antiangiogenic immune-modulating therapies evoke transdifferentiation of postcapillary venules into inflamed high-endothelial venules (HEVs) via lymphotoxin/lymphotoxin beta receptor (LT/LTβR) signaling. In turn, tumor HEVs boost intratumoral lymphocyte influx and foster permissive lymphocyte niches for PD1^- and PD1⁺TCF1⁺ CD8 T cell progenitors that differentiate into GrzB⁺PD1⁺ CD8 T effector cells. Tumor-HEVs require continuous CD8 and NK cell-derived signals revealing that tumor HEV maintenance is actively sculpted by the adaptive immune system through a feed-forward loop.

Tumor-associated high endothelial venules mediate lymphocyte entry into tumors and predict response to PD-1 plus CTLA-4 combination immunotherapy

Recruitment of lymphocytes into tumors is critical for anti-tumor immunity and efficacious immunotherapy. We show in murine models that tumor-associated high endothelial venules (TA-HEVs) are major sites of lymphocyte entry into tumors at baseline and upon treatment with anti-PD-1/anti-CTLA-4 immune checkpoint blockade (ICB). TA-HEV endothelial cells (TA-HECs) derive from post-capillary venules, co-express MECA-79⁺ HEV sialomucins and E/P-selectins, and are associated with homing and infiltration into tumors of various T cell subsets. Intravital microscopy further shows that TA-HEVs are the main sites of lymphocyte arrest and extravasation into ICB-treated tumors. Increasing TA-HEC frequency and maturation increases the proportion of tumor-infiltrating stem-like CD8⁺ T cells, and ameliorates ICB efficacy. Analysis of tumor biopsies from 93 patients with metastatic melanoma reveals that TA-HEVs are predictive of better response and survival upon treatment with anti-PD-1/anti-CTLA-4 combination. These studies provide critical insights into the mechanisms governing lymphocyte trafficking in cancer immunity and immunotherapy.

Stem-cell-like T cells have a specific entry gate to the tumor

Tumor-infiltrated T cells with stem-cell-like properties are important for determining the immunotherapy response. In this issue of Cancer Cell, Asrir and colleagues show that their entry requires specialized tumor-associated endothelial cells that resemble immature and inflamed lymph node vessels and that immunotherapy enhances the recruitment capacity of these endothelial cells.

Increased retinal venular calibre in acute infections

Population-based studies have demonstrated that increased retinal venular calibre is a risk factor for cardiac disease, cardiac events and stroke. Venular dilatation also occurs with diabetes, obesity, dyslipidemia and autoimmune disease where it is attributed to inflammation. This study examined whether the inflammation associated with infections also affected microvascular calibre. Participants with infections and CRP levels  >  100 mg/L were recruited from the medical wards of a teaching hospital and assisted to complete a demographic and vascular risk factor questionnaire, and to undergo non-mydriatic retinal photography (Canon CR5-45NM, Japan). They were then treated with appropriate antibiotics, and underwent repeat retinal imaging when their CRP levels had fallen to less than 100 mg/L. Retinal images were examined for arteriole and venular calibre using validated semi-automated software based on Knudtson's modification of the Parr-Hubbard formula (IVAN, U Wisconsin). Differences in inflammatory markers and calibre were examined using the paired t-test for continuous variables. Determinants of calibre were calculated from multiple linear regression analysis. Forty-one participants with respiratory (27, 66%), urinary (6, 15%), skin (5, 12%), or miscellaneous (3, 7%) infections were studied. After antibiotic treatment, participants' mean CRP levels fell from 172.9 ± 68.4 mg/L to 42.2 ± 28.2 mg/L (p < 0.0001) and mean neutrophil counts fell from 9 ± 4 × 109/L to 6 ± 3 × 109/L (p < 0.0001). The participants' mean venular calibre (CRVE) decreased from 240.9 ± 26.9 MU to 233.4 ± 23.5 MU (p = 0.0017) but arteriolar calibre (CRAE) was unchanged (156.9 ± 15.2 MU and 156.2 ± 16.0 MU, p = 0.84). Thirteen additional participants with infections had a CRP > 100 mg/L that persisted at review (199.2 ± 59.0 and 159.4 ± 40.7 mg/L, p = 0.055). Their CRAE and CRVE were not different before and after antibiotic treatment (p = 0.96, p = 0.78). Hospital inpatients with severe infections had retinal venular calibre that decreased as their infections resolved and CRP levels fell after antibiotic treatment. The changes in venular calibre with intercurrent infections may confound retinal vascular assessments of, for example, blood pressure control and cardiac risk.

Elevated postischemic tissue injury and leukocyte-endothelial adhesive interactions in mice with global deficiency in caveolin-2: role of PAI-1

Ischemia/reperfusion (I/R)-induced rapid inflammation involving activation of leukocyte-endothelial adhesive interactions and leukocyte infiltration into tissues is a major contributor to postischemic tissue injury. However, the molecular mediators involved in this pathological process are not fully known. We have previously reported that caveolin-2 (Cav-2), a protein component of plasma membrane caveolae, regulated leukocyte infiltration in mouse lung carcinoma tumors. The goal of the current study was to examine if Cav-2 plays a role in I/R injury and associated acute leukocyte-mediated inflammation. Using a mouse small intestinal I/R model, we demonstrated that I/R downregulates Cav-2 protein levels in the small bowel. Further study using Cav-2-deficient mice revealed aggravated postischemic tissue injury determined by scoring of villi length in H&E-stained tissue sections, which correlated with increased numbers of MPO-positive tissue-infiltrating leukocytes determined by IHC staining. Intravital microscopic analysis of upstream events relative to leukocyte transmigration and tissue infiltration revealed that leukocyte-endothelial cell adhesive interactions in postcapillary venules, namely leukocyte rolling and adhesion were also enhanced in Cav-2-deficient mice. Mechanistically, Cav-2 deficiency increased plasminogen activator inhibitor-1 (PAI-1) protein levels in the intestinal tissue and a pharmacological inhibition of PAI-1 had overall greater inhibitory effect on both aggravated I/R tissue injury and enhanced leukocyte-endothelial interactions in postcapillary venules in Cav-2-deficient mice. In conclusion, our data suggest that Cav-2 protein alleviates tissue injury in response to I/R by dampening PAI-1 protein levels and thereby reducing leukocyte-endothelial adhesive interactions.NEW & NOTEWORTHY The role of caveolin-2 in regulating ischemia/reperfusion (I/R) tissue injury and the mechanisms underlying its effects are unknown. This study uses caveolin-2-deficient mouse and small intestinal I/R injury models to examine the role of caveolin-2 in the leukocyte-dependent reperfusion injury. We demonstrate for the first time that caveolin-2 plays a protective role from the I/R-induced leukocyte-dependent reperfusion injury by reducing PAI-1 protein levels in intestinal tissue and leukocyte-endothelial adhesive interactions in postcapillary venules.

Cerebral Small Vessel Disease

Cerebral small vessel disease (CSVD) represents a cluster of various vascular disorders with different pathological backgrounds. The advanced vasculature net of cerebral vessels, including small arteries, capillaries, arterioles and venules, is usually affected. Processes of oxidation underlie the pathology of CSVD, promoting the degenerative status of the epithelial layer. There are several classifications of cerebral small vessel diseases; some of them include diseases such as Binswanger’s disease, leukoaraiosis, cerebral microbleeds (CMBs) and lacunar strokes. This paper presents the characteristics of CSVD and the impact of the current knowledge of this topic on the diagnosis and treatment of patients.

Association of retinal venular tortuosity with impaired renal function in the Northern Ireland Cohort for the Longitudinal Study of Ageing

BACKGROUND

Previous studies have identified retinal microvascular features associated with renal dysfunction. Biopsies are necessary to confirm kidney microvascular damage and retinal imaging may enable evaluation of microangiopathic characteristics reflecting renal changes associated with chronic kidney disease (CKD). We evaluated retinal microvascular parameters (RMPs) for associations with renal function in a cross-sectional analysis of the Northern Ireland Cohort for the Longitudinal Study of Ageing.

METHODS

RMPs (central retinal arteriolar/ venular equivalents [CRAE/CRVE], arteriolar to venular ratio [AVR], fractal dimension and tortuosity) were measured from optic disc centred fundus images using semi-automated software. Associations were assessed with multivariable regression analyses between RMPs and estimated glomerular filtration rate (eGFR) defined by serum creatinine (eGFRscr) and cystatin C (eGFRcys) and also CKD status characterised by eGFR < 60 mL/min/1.73m2. Regression models were adjusted for potential confounders including age, sex, diabetes, smoking status, educational attainment, cardiovascular disease, body mass index, antihypertensive medication, systolic blood pressure, triglycerides, high- and low-density lipoprotein levels.

RESULTS

Data were included for 1860 participants that had measures of renal function and retinal fundus images of sufficient quality for analysis. Participants had a mean age of 62.0 ± 8.5 yrs. and 53% were female. The mean eGFR for scr and cys were 82.2 ± 14.9 mL/min/1.73m2 and 70.7 ± 18.6 mL/min/1.73m2 respectively. eGFRcys provided lower estimates than eGFRscr resulting in a greater proportion of participants categorised as having CKD stages 3-5 (eGFRcys 26.8%; eGFRscr 7.9%). Multivariable regression analyses showed that increased venular tortuosity (OR = 1.30; 95%CI: 1.10, 1.54; P < 0.01) was associated with CKD stages 3-5 characterised by eGFRscr < 60 mL/min/1.73 m2. No additional associations between CKD status characterised by eGFRscr or with eGFRcys, were detected (P > 0.05). Multivariable regression failed to detect associations between CRAE, CRVE, AVR, fractal dimension or tortuosity and eGFRscr or eGFRcys (P > 0.05).

CONCLUSION

Increased retinal venular tortuosity was associated with CKD stages 3-5 defined by eGFRscr < 60 mL/min/1.73 m2, in an older population independent of potential confounding factors. These retinal measures may provide non-invasive microvascular assessment of associations with CKD.

Increased number of retinal vessels in acromegaly

OBJECTIVE

Excess of growth hormone (GH) and insulin-like growth factor 1 (IGF-1), as in acromegaly, is associated with increased risk of diabetes, but whether retinal vessels are altered is unknown. The aim of this study was to evaluate retinal vessel morphology in patients with acromegaly at diagnosis and after treatment and to describe the prevalence of diabetic retinopathy in patients with long-standing acromegaly and diabetes.

DESIGN

Two independent observational studies, one being prospective and the other retrospective and cross-sectional.

METHODS

Retinal vessel morphology of 26 patients with acromegaly was examined at diagnosis and 1 year after treatment and compared to 13 healthy controls. Cross-sectional evaluation of 39 patients with long-standing acromegaly and diabetes was performed. Fundus photographs were digitally analyzed for vessel morphology.

RESULTS

Patients with acromegaly had a median (interquartile range) of 34.3 (30.0-39.0) vessel branching points compared to 27.0 (24.0-29.0) for healthy controls (P < 0.001). Tortuosity of arterioles and venules remained unchanged. Vessel morphology did not change significantly after treatment. Patients with acromegaly and diabetes for a median of 14 years also had a high number of branching points (34.2 (32.5-35.6)), but the prevalence of diabetic retinopathy was not higher than expected in diabetic patients without acromegaly.

CONCLUSIONS

Patients with acromegaly have an increased number of vascular branching points in the retina without an alteration of macroscopic vessel morphology. This is consistent with an angiogenic effect of GH/IGF-1 in humans. The prevalence of diabetic retinopathy was not increased in patients with acromegaly and diabetes.

Retinal vessel diameters confound the relationship of pregnancy to retinopathy and infant outcomes in T1D

OBJECTIVES

To determine whether: 1) retinal vessel diameters in pregnant and non-pregnant women with type 1 diabetes (T1D) alter the relationship of pregnancy to severity of diabetic retinopathy (DR); and 2) retinal vessel diameters in early pregnancy alter the relationship of severity of DR in the mother to severe adverse outcome in the infant.

METHODS

Two cohorts of women with T1D, one composed of pregnant women and the other of non-pregnant women of child-bearing age, were recruited in Wisconsin. Baseline examinations (including retinal photography and collection of diabetes-related characteristics) were conducted, with follow-up approximately one year later. Retinal images were graded according to the modified Airlie House classification protocol, and retinal vessel diameters were measured from digitized images. The latter were included in analyses as central retinal arteriolar equivalent (CRAE) and central retinal venular equivalent (CRVE).

RESULTS

In multivariate models: 1) Pregnancy was significantly associated with both incidence (OR = 4.43, CI = 1.42-13.79) and progression (OR = 2.62, CI = 1.52-4.51) of DR. Neither CRAE nor CRVE were significant, but their addition modestly altered the associations of pregnancy to worsening DR; 2) Baseline retinopathy (OR = 1.28, CI = 1.05-1.57) was associated with severe adverse outcome in the infant. This association was unchanged by adjustment for retinal vessel diameters.

CONCLUSIONS

Pregnancy is associated with worsening DR in women with T1D. DR severity in early pregnancy is associated with severe adverse outcome in the infant. The retinal vessel diameters CRAE and CRVE were not associated with these outcomes but were modest confounders of the association of pregnancy to worsening DR.

High endothelial venules are associated with microsatellite instability, hereditary background and immune evasion in colorectal cancer

BACKGROUND

Microsatellite-unstable (MSI) tumours show a high load of mutational neoantigens, as a consequence of DNA mismatch repair deficiency. Consequently, MSI tumours commonly present with dense immune infiltration and develop immune evasion mechanisms. Whether improved lymphocyte recruitment contributes to the pronounced immune infiltration in MSI tumours is unknown. We analysed the density of high endothelial venules (HEV) and postcapillary blood vessels specialised for lymphocyte trafficking, in MSI colorectal cancers (CRC).

METHODS

HEV density was determined by immunohistochemical staining of FFPE tissue sections from MSI (n = 48) and microsatellite-stable (MSS, n = 35) CRCs. Associations with clinical and pathological variables were analysed.

RESULTS

We found elevated HEV densities in MSI compared with MSS CRCs (median 0.049 vs 0.000 counts/mm2, respectively, p = 0.0002), with the highest densities in Lynch syndrome MSI CRCs. Dramatically elevated HEV densities were observed in B2M-mutant Lynch syndrome CRCs, pointing towards a link between lymphocyte recruitment and immune evasion (median 0.485 vs 0.0885 counts/mm2 in B2M-wild-type tumours, p = 0.0237).

CONCLUSIONS

Our findings for the first time indicate a significant contribution of lymphocyte trafficking in immune responses against MSI CRC, particularly in the context of Lynch syndrome. High HEV densities in B2M-mutant tumours underline the significance of immunoediting during tumour evolution.

Retinal Vasculometry Associations with Cardiometabolic Risk Factors in the European Prospective Investigation of Cancer-Norfolk Study

PURPOSE

To examine associations between retinal vessel morphometry and cardiometabolic risk factors in older British men and women.

DESIGN

Retinal imaging examination as part of the European Prospective Investigation into Cancer-Norfolk Eye Study.

PARTICIPANTS

Retinal imaging and clinical assessments were carried out in 7411 participants. Retinal images were analyzed using a fully automated validated computerized system that provides novel measures of vessel morphometry.

METHODS

Associations between cardiometabolic risk factors, chronic disease, and retinal markers were analyzed using multilevel linear regression, adjusted for age, gender, and within-person clustering, to provide percentage differences in tortuosity and absolute differences in width.

MAIN OUTCOMES MEASURES

Retinal arteriolar and venular tortuosity and width.

RESULTS

In all, 279 802 arterioles and 285 791 venules from 5947 participants (mean age, 67.6 years; standard deviation [SD], 7.6 years; 57% female) were analyzed. Increased venular tortuosity was associated with higher body mass index (BMI; 2.5%; 95% confidence interval [CI], 1.7%-3.3% per 5 kg/m2), hemoglobin A1c (HbA1c) level (2.2%; 95% CI, 1.0%-3.5% per 1%), and prevalent type 2 diabetes (6.5%; 95% CI, 2.8%-10.4%); wider venules were associated with older age (2.6 μm; 95% CI, 2.2-2.9 μm per decade), higher triglyceride levels (0.6 μm; 95% CI, 0.3-0.9 μm per 1 mmol/l), BMI (0.7 μm; 95% CI, 0.4-1.0 per 5 kg/m2), HbA1c level (0.4 μm; 95% CI, -0.1 to 0.9 per 1%), and being a current smoker (3.0 μm; 95% CI, 1.7-4.3 μm); smoking also was associated with wider arterioles (2.1 μm; 95% CI, 1.3-2.9 μm). Thinner venules were associated with high-density lipoprotein (HDL) (1.4 μm; 95% CI, 0.7-2.2 per 1 mmol/l). Arteriolar tortuosity increased with age (5.4%; 95% CI, 3.8%-7.1% per decade), higher systolic blood pressure (1.2%; 95% CI, 0.5%-1.9% per 10 mmHg), in females (3.8%; 95% CI, 1.4%-6.4%), and in those with prevalent stroke (8.3%; 95% CI, -0.6% to 18%); no association was observed with prevalent myocardial infarction. Narrower arterioles were associated with age (0.8 μm; 95% CI, 0.6-1.0 μm per decade), higher systolic blood pressure (0.5 μm; 95% CI, 0.4-0.6 μm per 10 mmHg), total cholesterol level (0.2 μm; 95% CI, 0.0-0.3 μm per 1 mmol/l), and HDL (1.2 μm; 95% CI, 0.7-1.6 μm per 1 mmol/l).

CONCLUSIONS

Metabolic risk factors showed a graded association with both tortuosity and width of retinal venules, even among people without clinical diabetes, whereas atherosclerotic risk factors correlated more closely with arteriolar width, even excluding those with hypertension and cardiovascular disease. These noninvasive microvasculature measures should be evaluated further as predictors of future cardiometabolic disease.

Role of MAdCAM-1-Expressing High Endothelial Venule-Like Vessels in Colitis Induced in Mice Lacking Sulfotransferases Catalyzing L-Selectin Ligand Biosynthesis

Ulcerative colitis (UC) is a chronic inflammatory disease histologically characterized by diffuse mononuclear cell infiltrates in colonic mucosa. These inflammatory cells are considered to be recruited via high endothelial venule (HEV)-like vessels displaying mucosal addressin cell adhesion molecule 1 (MAdCAM-1), the ligand for α4β7 integrin, and/or peripheral lymph node addressin (PNAd), an L-selectin ligand. 6- O-sulfation of N-acetylglucosamine in the carbohydrate moiety of PNAd is catalyzed exclusively by N-acetylglucosamine-6- O-sulfotransferase 1 (GlcNAc6ST-1) and GlcNAc6ST-2. To determine the role of 6- O-sulfation of N-acetylglucosamine on HEV-like vessels in UC, we used a chronic dextran sulfate sodium-induced colitis model using mice deficient in both GlcNAc6ST-1 and GlcNAc6ST-2. We found that more inflammatory cells, with expression of tumor necrosis factor α, were infiltrated in double knockout mouse colitis compared with that in wild-type mice. Moreover, the number of MAdCAM-1-positive vessels was increased in double knockout mouse colitis, and these vessels were bound by E-selectin•IgM chimeras that bind to unsulfated sialyl Lewis X (sLeX). These findings suggest that interactions between MAdCAM-1 and α4β7 integrin and/or unsulfated sLeX and L-selectin may become a dominant mechanism for inflammatory cell recruitment in the absence of 6-sulfo sLeX and contribute to more severe colitis phenotypes seen in double knockout mice.

Isolating the influences of fluid dynamics on selectin-mediated particle rolling at venular junctional regions

The objective of this study was to isolate the impact of hydrodynamics on selectin-mediated cell rolling in branched microvessels. Significant advancements have been made in furthering the understanding of complex interactions between biochemical and physical factors in the inflammatory cascade in simplified planar geometries. However, few studies have sought to quantify the effects of branched configurations and to isolate the effects of associated fluid forces. Experimental techniques were developed to perform in vitro adhesion experiments in Y-shaped micro-slides. The micro-slides were coated with P-selectin and microspheres coated with Sialyl-Lewis^x were observed as they rolled in the chambers at different wall shear stresses. Study results revealed that microsphere rolling velocities and rolling flux were lowest in regions closest to the apex of a junctional region and were dependent on both branch angle and wall shear stress. The regions closest to the junctional region were shown to have low bulk flow velocities and shear stresses using computational fluid dynamics (CFD) modeling. Collectively, the study demonstrates that despite the presence of a uniform coating of P-selectin, hydrodynamic factors associated with the chamber geometry yield non-uniform effects on particle behavior. These findings could explain why cells have been observed to preferentially adhere or transmigrate near junctional regions. Future characterization of inflammatory processes in microvascular network configurations is therefore crucial for furthering our fundamental understanding of inflammation.

Association of Retinal Vascular Caliber and Age-Related Macular Degeneration in Patients With the Acquired Immunodeficiency Syndrome

Purpose

To evaluate the relationship between retinal vascular caliber and AMD in patients with AIDS.

Methods

Participants enrolled in the Longitudinal Study of the Ocular Complications of AIDS had retinal photographs taken at enrollment. Retinal vascular caliber (central retinal artery equivalent [CRAE] and central retinal vein equivalent [CRVE]) and intermediate-stage AMD were determined from these retinal photographs. Photographs were evaluated by graders at a centralized reading center, using the Age-Related Eye Disease Study grading system for AMD and semiautomated techniques for evaluating retinal vascular caliber.

Results

Of the 1171 participants evaluated, 110 (9.4%) had AMD and 1061 (90.6%) did not. Compared with participants without AMD, participants with AMD had larger mean CRAEs (151 ± 16 μm versus 147 ± 16 μm; P = 0.009) and mean CRVEs (228 ± 24 μm versus 223 ± 25 μm; P = 0.02). The unadjusted differences were: CRAE, 4.3 μm (95% confidence interval [CI] 1.1-7.5; P = 0.009) and CRVE, 5.5 μm (95% CI 0.7-10.3; P = 0.02). After adjustment for age, race/ethnicity, sex, human immunodeficiency syndrome (HIV) transmission category, smoking, enrollment and nadir CD4+ T cells, and enrollment and maximum HIV load, the differences between patients with and without AMD were as follows: CRAE, 5.4 μm (95% CI 2.3-8.5; P = 0.001) and CRVE, 6.0 μm (95% CI 1.4-10.6; P = 0.01).

Conclusions

In patients with AIDS, AMD is associated with greater retinal arteriolar and venular calibers, suggesting a role for shared pathogenic mechanisms, such as persistent systemic inflammation.

Arterial thrombosis in the context of HCV-associated vascular disease can be prevented by protein C

Hepatitis C virus (HCV) infection is a major problem worldwide. HCV is not limited to liver disease but is frequently complicated by immune-mediated extrahepatic manifestations such as glomerulonephritis or vasculitis. A fatal complication of HCV-associated vascular disease is thrombosis. Polyriboinosinic:polyribocytidylic acid (poly (I:C)), a synthetic analog of viral RNA, induces a Toll-like receptor 3 (TLR3)-dependent arteriolar thrombosis without significant thrombus formation in venules in vivo. These procoagulant effects are caused by increased endothelial synthesis of tissue factor and PAI-1 without platelet activation. In addition to human umbilical endothelial cells (HUVEC), human mesangial cells (HMC) produce procoagulatory factors, cytokines and adhesion molecules after stimulation with poly (I:C) or HCV-containing cryoprecipitates from a patient with a HCV infection as well. Activated protein C (APC) is able to prevent the induction of procoagulatory factors in HUVEC and HMC in vitro and blocks the effects of poly (I:C) and HCV-RNA on the expression of cytokines and adhesion molecules in HMC but not in HUVEC. In vivo, protein C inhibits poly (I:C)-induced arteriolar thrombosis. Thus, endothelial cells are de facto able to actively participate in immune-mediated vascular thrombosis caused by viral infections. Finally, we provide evidence for the ability of protein C to inhibit TLR3-mediated arteriolar thrombosis caused by HCV infection.

Appearance of High Endothelial Venule-Like Vessels in Benign Prostatic Hyperplasia is Associated With Lower Urinary tract Symptoms

BACKGROUND

Chronic prostatic inflammation is implicated in the pathogenesis of benign prostatic hyperplasia (BPH)-associated lower urinary tract symptoms (LUTS). Previous studies evaluated the degree of chronic prostatic inflammation based on histological scores, which may contain subjective factors. We previously demonstrated that the number of high endothelial venule (HEV)-like vessels correlates positively with the magnitude of inflammation in chronic inflammatory gastrointestinal diseases. Here, we evaluated the degree of BPH-associated chronic prostate inflammation based on appearance of HEV-like vessels and determined whether the extent of inflammation correlated with LUTS severity, as evaluated by a urodynamic study.

METHODS

Eighty-six BPH tissue specimens derived from patients who had undergone urodynamic analysis were immunostained for CD34 and MECA-79 to determine HEV-like vessel number. Triple immunohistochemistry for either CD3 and CD20 or CD4 and CD8, together with MECA-79, was conducted to identify lymphocyte subsets associated with HEV-like vessels. We also determined whether the magnitude of chronic prostatic inflammation, as assessed by HEV-like vessel number, correlated with the degree of LUTS.

RESULTS

HEV-like vessels were induced in lymphoid aggregates seen frequently in BPH. The number of HEV-like vessels positively correlated not only with the magnitude of chronic prostatic inflammation but also with the degree of LUTS, particularly with symptoms associated with voiding function, which was measured objectively in a pressure flow study.

CONCLUSIONS

Chronic prostate inflammation may promote BPH and resulting voiding dysfunction. Assessment of the number of HEV-like vessels could be a surrogate for identifying the degree of chronic prostatic inflammation. Prostate 77:794-802, 2017. © 2017 Wiley Periodicals, Inc.

Role of TNF-α and Its Receptors in Pericoronitis

The classic stimulus for cellular cytokine production is bacterial lipopolysaccharide (endotoxin). It was therefore hypothesized that tumor necrosis factor-α (TNF-α) may be responsible for pericoronitis. TNF-α and its receptors were detected by immunohistochemical staining in third molar pericoronitis in ten patients and ten healthy control samples. The percentage of TNF-α positive cells was high in pericoronitis (p = 0.0317). TNF receptors TNF-R1 and TNF-R2 were found in macrophage- and fibroblast-like cells, vascular endothelial cells in post-capillary venules, and basal epithelial cells in pericoronitis, but were only weakly expressed in controls. Increased expression of interleukin-1β and vascular cell adhesion molecule-1 was found as a biological indicator of TNF-α ligand-receptor interaction. Explanted tissues acquired destructive potential upon TNF-α stimulation, whereas TNF-α blockers controlled it in inflamed tissues. These findings suggest that, in pericoronitis, inflammatory and resident cells produce and respond to potent pro-inflammatory cytokine TNF-α, with pathogenic and potential therapeutic relevance.

Carotid Atherosclerosis, Cerebrospinal Fluid Pressure, and Retinal Vessel Diameters: The Asymptomatic Polyvascular Abnormalities in Community Study

Purpose

To assess relationships between carotid artery atherosclerosis and retinal arteriolar and venular diameters.

Methods

The community-based longitudinal Asymptomatic Polyvascular Abnormalities Community Study (APAC) included a sub-population of the Kailuan study which consisted of 101,510 employees and retirees of a coal mining industry. Based on the Chinese National Census 2010 and excluding individuals with history of cerebrovascular ischemic events, 4004 individuals were included into the APAC. All participants underwent a detailed clinical examination including blood laboratory tests and carotid artery duplex ultrasound examination. The cerebrospinal fluid pressure (CSFP) was estimated using the formula: CSFP[mmHg] = 0.44xBody Mass Index[kg/m²]+0.16xDiastolic Blood Pressure[mmHg]–0.18 x Age[Years]–1.91.

Results

In multivariable analysis (goodness of fit r²:0.12), thicker retinal arteries were associated with a thinner common carotid artery intima-media thickness (IMT) (P = 0.002; standardized regression coefficient beta:-0.06; non-standardized regression coefficient B:-6.92;95% confidence interval (CI):-11.2,-2.61) after adjusting for thicker retinal nerve fiber layer (P<0.001;beta:0.18;B:0.35;95%CI:0.28,0.42), lower diastolic blood pressure (P<0.001;beta:-0.16;B:-0.17;95%CI:-0.21,-0.3), younger age (P<0.001;beta:-0.08; B:-0.16;95%;CI:-0.25,-0.08), and less abdominal circumference (P = 0.003;beta:-0.06;B:-0.11;95%CI:-0.18,-0.03). Thicker retinal vein diameter was associated (r = 0.40) with higher estimated CSFP (P<0.001;beta:0.09;B:0.78;95%CI:0.47,1.08) after adjusting for wider retinal arteries (P<0.001;beta:0.27;B:0.36;95%CI:0.31,0.41), thicker retinal nerve fiber layer thickness (P = 0.03;beta:0.22;B:0.56;95%CI:0.46,0.65) and male gender (P<0.001;beta:-0.08;B:-3.98;95%CI:-5.88,2.09).

Conclusions

Thinner retinal artery diameter was significantly, however weakly, associated with increased common carotid artery IMT. It suggests that retinal microvascular changes were only week indicators for an atherosclerotic carotid artery pathology. Thicker retinal vein diameter was associated with higher estimated CSFP, confirming associations between higher estimated CSFP and higher incidence of retinal vein occlusion.

[Retinal vessel diameter variation analysis in diabetic patients]

OBJECTIVE

To explore the influence factors of retinal vascular changes in diabetes patients.

METHODS

Case control study. One hundred and fifty-five type 2 diabetes patients were divided into NDR group (n=80) and DR group (n=70) according to the presence of diabetic retinopathy. Fundus photographs were taken after pupil dilated, the diameter of retinal arterioles and venules were measured between 1.0 PD and 1.5 PD. To analyze the relationship between retinal artery diameter, vein diameter and hypertension, diabetes duration, and DR stage. With retinal artery and vein diameter as the dependent variable, DR stage, hypertension, diabetes duration, insulin using time and age as independent variables, using step method, multiple linear regression was undergoing.

RESULTS

The diameter of retinal vein in DR group and NDR group were (90.37+7.95) and (83.45±7.80) μm, the difference was statistically significant (t=5.446, P=0.000). Retinal vein diameter was positively correlated with DR stage and diabetes duration (r=0.377, 0.250; P=0.000, 0.002). DR stage (b=2.382, P=0.000) had a linear relationship with retinal vein diameter (R(2)=0.142, F=25.285). The regression equation was: retinal vein diameter =84.269+ 2.382 · DR stage. Retinal artery diameter was negatively correlated with DR stage, diabetes duration, and hypertension duration (r=-0.453, -0.343, -0.199. P=0.000, 0.000, 0.013). DR stage (b=-2.091, P=0.000) and age (b=-0.182, P=0.000) has a linear relationship with retinal artery diameter (R(2)=0.290, F=31.088). The regression equation was: retinal artery diameter =64.011-2.091·DR stage -0.182·age.

CONCLUSIONS

With DR developed, retinal vein diameter increases, retinal artery diameter decreases in diabetic patients. The duration of diabetes mellitus and hypertension were not related to the diameter of retinal artery and vein.

Automatic retinal vessel classification using a Least Square-Support Vector Machine in VAMPIRE

It is important to classify retinal blood vessels into arterioles and venules for computerised analysis of the vasculature and to aid discovery of disease biomarkers. For instance, zone B is the standardised region of a retinal image utilised for the measurement of the arteriole to venule width ratio (AVR), a parameter indicative of microvascular health and systemic disease. We introduce a Least Square-Support Vector Machine (LS-SVM) classifier for the first time (to the best of our knowledge) to label automatically arterioles and venules. We use only 4 image features and consider vessels inside zone B (802 vessels from 70 fundus camera images) and in an extended zone (1,207 vessels, 70 fundus camera images). We achieve an accuracy of 94.88% and 93.96% in zone B and the extended zone, respectively, with a training set of 10 images and a testing set of 60 images. With a smaller training set of only 5 images and the same testing set we achieve an accuracy of 94.16% and 93.95%, respectively. This experiment was repeated five times by randomly choosing 10 and 5 images for the training set. Mean classification accuracy are close to the above mentioned result. We conclude that the performance of our system is very promising and outperforms most recently reported systems. Our approach requires smaller training data sets compared to others but still results in a similar or higher classification rate.

Brain venular pattern by 7T MRI correlates with memory and haemoglobin in sickle cell anaemia

Sickle cell anaemia (SCA) is a hereditary hemoglobinopathy characterised by extensive vascular dysfunction that stems from inflammation, thrombosis and occlusion of post-capillary venules. Cognitive impairment is a neurological complication of SCA whose pathogenesis is unknown. We hypothesised that cerebral venular abnormalities are linked to cognitive impairment in SCA. Thus, we employed 7T magnetic resonance imaging (MRI) to examine the association between venular density and cognitive function in homozygous SCA. We quantified the density of total, long, and short venules in pre-defined regions of interest between the frontal and occipital cornu on each hemisphere. Cognitive function was assessed using the Hopkins Verbal Learning Test - Revised (HVLT-R) test of learning and memory. Patients (n=11) were compared with race, age and gender-equated controls (n=7). Compared to controls, patients had an overall venular rarefaction, with significantly lower density of long venules and greater density of short venules which was inversely related to HVLT-R performance and haemoglobin. To our knowledge, this is the first 7T MRI study in SCA and first report of associations between cerebral venular patterns and cognitive performance and haemoglobin. Future studies should examine whether these novel neuroimaging markers predict cognitive impairment longitudinally and are mechanistically linked to severity of anaemia.

Expression of ephrinB2 and EphB4 in a neonatal rat model of periventricular white matter damage

BACKGROUND

Periventricular white matter damage (PWMD), also termed periventricular leukomalacia, is the predominant neurologic lesion in preterm infants. It appears to relate in part to the development of the vascular supply to the cerebral white matter. We investigated whether, in case of severe hypoxia-ischemia, the vascular system would be subject to severe damage or remodeled.

AIMS

To evaluate microvessel density (MVD) and the use of ephrinB2 and its receptor EphB4 to mark arterioles and venules to establish the correct anatomic assignment of the remodeled vessels in a hypoxia-induced PWMD rat model.

METHODS

Postnatal day 3 rats underwent permanent ligation of the right common carotid artery followed by 6% O2 for 4 h (hypoxia-ischemia) or sham operation and normoxic exposure (sham). MVD and levels of ephrinB2 and EphB4, which are respectively regarded as relatively specific molecular markers of arteries and veins, were determined at postnatal day 7.

RESULTS

Compared with sham rats, MVD, ephrinB2 and EphB4 levels were higher in the brains of hypoxic-ischemic rats. Similar percentages of vessels expressed ephrinB2 and EphB4 in sham rats, but expression of ephrinB2 was greater in brains injured by hypoxia-ischemia.

CONCLUSIONS

Following hypoxic-ischemic injury to the rat brain, microvessels were remodeled and more arterioles than venules were acquired.

Nitric oxide synthase promotes distension-induced tracheal venular leukocyte adherence

The process of leukocyte recruitment to the airways in real time has not been extensively studied, yet airway inflammation persists as a major contributor to lung pathology. We showed previously in vivo, that neutrophils are recruited acutely to the large airways after periods of airway distension imposed by the application of positive end-expiratory pressure (PEEP). Given extensive literature implicating products of nitric oxide synthase (NOS) in lung injury after ventilatory over-distension, we questioned whether similar mechanisms exist in airway post-capillary venules. Yet, endothelial nitric oxide has been shown to be largely anti-inflammatory in other systemic venules. Using intravital microscopy to visualize post-capillary tracheal venules in anesthetized, ventilated mice, the number of adherent leukocytes was significantly decreased in eNOS^-/- mice under baseline conditions (2±1 cell/60 min observation) vs wild type (WT) C57BL/6 mice (7±2 cells). After exposure to PEEP (8 cmH₂O for 1 min; 5 times), adherent cells increased significantly (29±5 cells) in WT mice while eNOS^-/- mice demonstrated a significantly decreased number of adherent cells (11±4 cells) after PEEP. A similar response was seen when thrombin was used as the pro-inflammatory stimulus. In addition, mouse tracheal venular endothelial cells studied in vitro after exposure to cyclic stretch (18% elongation) or thrombin both demonstrated increased p-selectin expression that was significantly attenuated by N^G-nitro-L-arginine methyl ester, N-acetylcysteine amide (NACA) and excess BH₄. In vivo treatment with the ROS inhibitor NACA or co-factor BH₄ abolished completely the PEEP-induced leukocyte adherence. These results suggest that pro-inflammatory stimuli cause leukocyte recruitment to tracheal endothelium in part due to eNOS uncoupling.

Complete blood count and retinal vessel calibers

Objective

The influence of hematological indices such as complete blood count on microcirculation is poorly understood. Retinal microvasculature can be directly visualized and vessel calibers are associated with a range of ocular and systemic diseases. We examined the association of complete blood count with retinal vessel calibers.

Methods

Cross-sectional population-based Blue Mountains Eye Study, n = 3009, aged 49+ years. Complete blood count was measured from fasting blood samples taken at baseline examination, 1992–4. Retinal arteriolar and venular calibers were measured from digitized retinal photographs using a validated semi-automated computer program.

Results

All analyses adjusted for age, sex, systolic blood pressure, diabetes, smoking and fellow vessel caliber. Higher hematocrit, white cell count and platelet count were associated with narrower arteriolar caliber (p = 0.02, 0.03 and 0.001 respectively), while higher hemoglobin, hematocrit, red cell count, white cell count and platelet count were associated with wider venular caliber (p<0.0001 for all). Each quintile increase in hematocrit, white cell count and platelet count was associated with approximately 0.5 µm narrower arteriolar caliber; whereas each quintile increase in all of the complete blood count components was associated with approximately 1–2 µm wider venular caliber.

Conclusions

These associations show that elevated levels of hematological indices can have adverse effects on the microcirculation.

A simplified minimally invasive technique for the treatment of venous lakes

A simplified approach to treat venous lakes of the vermillion lip is presented. Our method involves the use of a 30 gauge hypodermic needle to deliver a low-powered, high-frequency electrical current from a hyfrecator power source into the venous lake lesion.

Microvascular findings in patients with systemic lupus erythematosus assessed by fundus photography with fluorescein angiography

OBJECTIVES

Although a series of trials support systemic lupus erythematosus (SLE) is associated with increased atherosclerosis and cardiovascular events, the link between microvascular structural change and the disease activity of SLE is not defined. We measured retinal microvasculature change by fundus photography with fluorescein angiography (FAG) and investigated the association between retinal vasculature and clinical parameters of SLE.

METHODS

Fifty SLE patients and fifty healthy controls were included. Morphometric and quantitative features of the capillary image including retinal vascular sign and vessel diameters were measured with fundus photography and FAG. Information concerning SLE duration, cumulative dose of steroids and/or immunosuppressive drug intake was recorded, and autoantibodies were checked. SLE activity was assessed by SLE disease activity index (SLEDAI).

RESULTS

The mean central retinal arteriolar equivalent (CRAE) was 89.7±14.5 μm in SLE patients, showing narrower arteriole than that of controls (102.2±11.3 μm). The mean central retinal venular equivalents (CRVE) was 127.7±14.8 μm in SLE patients, also, narrower than that of controls (144.1±14.2 μm), but both reached no statistical significance (p=0.154, p=0.609, respectively). Retinopathy was found in 26% of SLE patients. SLE patients with retinopathy were older than those without it, but reached no statistical significance. Disease duration, antidsDNA, and complement levels had no effect on the presence of retinopathy. SLE patients with retinopathy had a tendency to have higher cumulative steroid doses, hsCRP and IgG aCL levels than those without retinopathy. With multiple regression analysis, hsCRP and IgG aCL were identified as contributing factors to the decreased CRAE, whereas no contributing factor was found to CRVE.

CONCLUSIONS

Retinopathy and retinal arteriolar narrowing were more common in SLE patients, and retinal arteriolar diameter had significant correlation with hsCRP and IgG aCL levels. Retinal imaging is a comparative method for the assessment of microvascular findings of SLE patients.

Microcirculatory rarefaction in South Asians - a potential mechanism for increased cardiovascular risk and diabetes

People of South Asian descent have an increased risk of cardiovascular disease (CVD) and diabetes, but little is known about the microcirculation in South Asian people despite evidence that this plays an important role in the aetiology of CVD. We compared the retinal microcirculation in a population-based sample of 287 middle-aged adults (144 European 143 South Asian) matched for age and sex. Retinal photographs were taken and analysed using a validated semi-automated program and microvascular measures were compared. Blood pressure, anthropometry and fasting bloods were also measured. South Asians had significantly fewer arteriolar and venular vessels and bifurcations. Arterioles and venules were longer and venules were also more tortuous in South Asians. These differences were not explained by adjustment for traditional risk factors including blood pressure, body mass index, diabetes or measures of insulin resistance. People of South Asian descent have rarefaction of the retinal microcirculation compared to age-sex matched individuals of European descent. Reduced microvascular density could contribute to the elevated risk of CVD and impaired glucose tolerance in South Asian people.

Lymphoid aggregates that resemble tertiary lymphoid organs define a specific pathological subset in metal-on-metal hip replacements

Aseptic lymphocyte-dominated vasculitis-associated lesion (ALVAL) has been used to describe the histological lesion associated with metal-on-metal (M-M) bearings. We tested the hypothesis that the lymphoid aggregates, associated with ALVAL lesions resemble tertiary lymphoid organs (TLOs). Histopathological changes were examined in the periprosthetic tissue of 62 M-M hip replacements requiring revision surgery, with particular emphasis on the characteristics and pattern of the lymphocytic infiltrate. Immunofluorescence and immunohistochemistry were used to study the classical features of TLOs in cases where large organized lymphoid follicles were present. Synchrotron X-ray fluorescence (XRF) measurements were undertaken to detect localisation of implant derived ions/particles within the samples. Based on type of lymphocytic infiltrates, three different categories were recognised; diffuse aggregates (51%), T cell aggregates (20%), and organised lymphoid aggregates (29%). Further investigation of tissues with organised lymphoid aggregates showed that these tissues recapitulate many of the features of TLOs with T cells and B cells organised into discrete areas, the presence of follicular dendritic cells, acquisition of high endothelial venule like phenotype by blood vessels, expression of lymphoid chemokines and the presence of plasma cells. Co-localisation of implant-derived metals with lymphoid aggregates was observed. These findings suggest that in addition to the well described general foreign body reaction mediated by macrophages and a T cell mediated type IV hypersensitivity response, an under-recognized immunological reaction to metal wear debris involving B cells and the formation of tertiary lymphoid organs occurs in a distinct subset of patients with M-M implants.

Improved arteriole-to-venule ratio of retinal vessels resulting from bariatric surgery

Obesity causes increased morbidity and mortality from metabolic and cardiovascular disease (CVD). We investigated the effect of bariatric surgery on endothelial dysfunction (ED) in retinal vessels as a marker of metabolic and cardiovascular risk in patients with obesity WHO III.Thirty consecutive patients (19/11, w/m) were evaluated by anthropometry, lipid profile, and oral glucose tolerance test before and after bariatric surgery (Mannheim Obesity Study (MOS); NCT 00770276). Risk stratification was performed by the presence of metabolic syndrome (MetS) according to ATP-III (adult treatment panel-III). Subclinical atherosclerosis was assessed by measurement of intima-media thickness (IMT). Flicker light response of retinal vessels was used as measures of ED. We measured their arteriole-to-venule ratio (AVR) for evaluation of vascular pathology. After a median of 9 months following bariatric surgery, mean weight loss was 39.4 kg (37.3%). Remission of impaired glucose metabolism was achieved in 53.3% of affected patients. Dyslipidemia improved significantly (triglycerides -61.3 mg/dl, P < 0.0001, total cholesterol -28.2 mg/dl, P = 0.002, and low-density lipoprotein cholesterol were reduced -24.5 mg/dl, P = 0.008). This resulted in a significant reduction of patients classified for MetS (27 vs. 9, P < 0.0001). Adiponectin increased by 2.08 µg/l (P = 0.032) and high sensitivity C-reactive protein (hs-CRP) and soluble intercellular cell adhesion molecule (sICAM) decreased (-7.3 mg/l, P < 0.0001 and -146.4 ng/ml, P = 0.0006). AVR improved significantly (+0.04, P < 0.0001), but neither Flicker light response nor IMT changed significantly. Retinal AVR is ameliorated after bariatric intervention. As an increased AVR results from either or both widening retinal arteriolar caliber and narrowing retinal venular caliber, an improvement in small vessel profile is evident 9 months after bariatric surgery.

High interstitial fluid pressure is associated with tumor-line specific vascular abnormalities in human melanoma xenografts

Purpose

Interstitial fluid pressure (IFP) is highly elevated in many solid tumors. High IFP has been associated with low radiocurability and high metastatic frequency in human melanoma xenografts and with poor survival after radiation therapy in cervical cancer patients. Abnormalities in tumor vascular networks have been identified as an important cause of elevated tumor IFP. The aim of this study was to investigate the relationship between tumor IFP and the functional and morphological properties of tumor vascular networks.

Materials and Methods

A-07-GFP and R-18-GFP human melanomas growing in dorsal window chambers in BALB/c nu/nu mice were used as preclinical tumor models. Functional and morphological parameters of the vascular network were assessed from first-pass imaging movies and vascular maps recorded after intravenous bolus injection of 155-kDa tetramethylrhodamine isothiocyanate-labeled dextran. IFP was measured in the center of the tumors using a Millar catheter. Angiogenic profiles of A-07-GFP and R-18-GFP cells were obtained with a quantitative PCR array.

Results

High IFP was associated with low growth rate and low vascular density in A-07-GFP tumors, and with high growth rate and high vascular density in R-18-GFP tumors. A-07-GFP tumors showed chaotic and highly disorganized vascular networks, while R-18-GFP tumors showed more organized vascular networks with supplying arterioles in the tumor center and draining venules in the tumor periphery. Furthermore, A-07-GFP and R-18-GFP cells differed substantially in angiogenic profiles. A-07-GFP tumors with high IFP showed high geometric resistance to blood flow due to high vessel tortuosity. R-18-GFP tumors with high IFP showed high geometric resistance to blood flow due to a large number of narrow tumor capillaries.

Conclusions

High IFP in A-07-GFP and R-18-GFP human melanoma xenografts was primarily a consequence of high blood flow resistance caused by tumor-line specific vascular abnormalities.

Acute lung injury induced by Staphylococcal enterotoxin B: disruption of terminal vessels as a mechanism of induction of vascular leak

The current hypothesis of alveolar capillary membrane dysfunction fails to completely explain the severe and persistent leak of protein-rich fluid into the pulmonary interstitium, seen in the exudative phase of acute lung injury (ALI). The presence of intact red blood cells in the pulmonary interstitium may suggest mechanical failure of pulmonary arterioles and venules. These studies involved the pathological and ultrastructural evaluation of the pulmonary vasculature in Staphylococcal enterotoxin B (SEB)-induced ALI. Administration of SEB resulted in a significant increase in the protein concentration of bronchoalveolar lavage fluid and vascular leak in SEB-exposed mice compared to vehicle-treated mice. In vivo imaging of mice demonstrated the pulmonary edema and leakage in the lungs of SEB-administered mice. The histopathological studies showed intense clustering of inflammatory cells around the alveolar capillaries with subtle changes in architecture. Electron microscopy studies further confirmed the diffuse damage and disruption in the muscularis layer of the terminal vessels. Cell death in the endothelial cells of the terminal vessels was confirmed with TUNEL staining. In this study, we demonstrated that in addition to failure of the alveolar capillary membrane, disruption of the pulmonary arterioles and venules may explain the persistent and severe interstitial and alveolar edema.

Eosinophilic venulitis in the small intestines in a mouse model of late asthma

The allergen-unchallenged enteric lesions in late allergic asthma are largely unknown. To clarify this point, BALB/c mice were sensitized by ovalbumin (OVA)/aluminum adjuvant intraperitoneally two times (on days 0 and 10) and then challenged with OVA intranasally on day 14 (asthma group). Four days after the challenge, small intestinal lesions were examined. By this treatment, diarrhea was not observed in the asthma group. Compared to the controls with or without OVA sensitization and/or OVA challenge, the asthma group developed eosinophilic venulitis without an increase in mucosal mast cells in small intestines, whereas intestinal epithelial cells were relatively intact. A few numbers of interleukin (IL)-4(+) and IL-5(+) lymphoid cells were recognized in intestines in the asthma group, but not in the controls. Expression of vascular cell adhesion molecule-1 on venular endothelium and eotaxin-2(+) eosinophils, but not epithelial cells, in intestines were detected in the asthma group, but not in the controls. Total IgE, OVA-specific IgE and eotaxin, and IL-5, but not interferon-γ, were produced systemically in the asthma group compared to the controls. The present study suggests that eosinophilic venulitis without mast cells in the intestine may be induced by the systemic, but not by local, helper T 2-type responses. In addition, eosinophilic venulitis in small intestines may be subclinical enteric lesions.

2011 Young Surgeon's Award Winner: high endothelial venules: a novel prognostic marker in cancer metastasis and the missing link?

INTRODUCTION

The extent of lymph nodes (LNs) metastasis is a major determinant for the staging and the most reliable adverse prognostic factor. Primary tumours can induce lymphatics and vasculature reorganisations within sentinel LN before the arrival of cancer cells and these key blood vessels are identified as high endothelial venules (HEV). The alterations of HEV in the presence of cancer, coupled with the increased proliferation rate of the endothelial cells, results in a functional shift of HEV from immune response mediator to blood flow carrier. We aim to evaluate tumour-induced vascularisation in regional LN of cancer patients by studying the morphological and functional alterations of HEV and its correlation to clinico-pathological features.

MATERIALS AND METHODS

This multi-centre study with a prospective database identified 65 consecutive patients with tongue squamous cell carcinoma (SCC) who underwent primary surgical treatment from 2001 to 2005. Immunohistochemical staining for HEV and image analysis were performed and analysed with correlation to the patients' clinico-pathological features.

RESULTS

The total number of HEV is significantly associated to disease-free interval when controlling for the group (P = 0.022) as well as combining both groups as one cohort (P = 0.023). There is also a similar association comparing the HEV parameters to overall survival.

CONCLUSION

Our results suggest that HEV possibly plays a key role in the pathogenesis of lymphatic and subsequent distant metastases and may provide the missing link in cancer metastasis. Confirmation of this hypothesis would offer a novel therapeutic approach to preventing metastasis by blocking the remodeling processes of HEV in LN.

Differential association of retinal arteriolar and venular caliber with diabetes and retinopathy

AIMS

To describe the relationship of retinal arteriolar and venular caliber with diabetes, retinopathy and hyperglycemia, in an Asian Indian population.

METHODS

This was a population-based cross-sectional study of 3400 (75.6% response rate) Singapore ethnic Indians aged 40-80 years. Central retinal arteriolar equivalent (CRAE) and central retinal venular equivalent (CRVE) were obtained using a validated computer-assisted program. Diabetes mellitus was identified using standardized criteria. Diabetic retinopathy was graded based on the modified Airlie House Classification System.

RESULTS

There were 980 (32.2%) participants with diabetes. Of these, 327 (33.4%) had diabetic retinopathy. After multivariate adjustment, diabetic persons had a wider CRAE (145.23μm vs 142.38μm, P<0.001). This relationship was stronger in persons without hyperlipidemia (P-interaction<0.1). Among diabetic participants, wider CRVE was related to increasing severity of retinopathy (P for trend<0.05) and this association may be altered by hypertensive status. Retinal arteriolar caliber widened with increasing glucose (P<0.001) and HbA1C (P<0.001) levels.

CONCLUSIONS

In Indian adults, wider retinal arteriolar caliber is associated with diabetes and hyperglycemia, while wider retinal venular caliber is associated with diabetic retinopathy. This is consistent with white populations and confirms the differential systemic association of retinal vascular caliber in Asian Indians.

Retinal vascular tortuosity in persons with diabetes and diabetic retinopathy

AIM/HYPOTHESIS

The aim of this hypothesis was to examine the association of retinal vessel tortuosity with diabetes and diabetic retinopathy (DR).

METHODS

A clinic-based study of 327 participants (224 with diabetes and 103 non-diabetic controls) aged ≥ 18 years. DR was graded from fundus photographs according to the modified Airlie House Classification system and categorised into mild non-proliferative DR (NPDR), moderate NPDR and vision-threatening DR (VTDR). Retinal vessel tortuosity was measured from disc-centred retinal photographs. Measurements were taken, using a semi-automated computer program by a single grader, of arterioles and venules within 0.5 to 2 disc diameters away from the optic disc.

RESULTS

There were 114 (44%) participants with DR. In the multivariate analysis, retinal arteriolar and venular tortuosity were increased in participants with diabetes without DR (mean difference 12.4 × 10(-5) and 13.3 × 10(-5), respectively; both p < 0.05) and in those with DR (mean difference 15.4 × 10(-5) and 15.0 × 10(-5), respectively; both p < 0.01) compared with non-diabetic participants. Among participants with diabetes, increased arteriolar tortuosity was significantly associated with mild NPDR (OR 1.53, 95% CI 1.03-2.05, per SD increase in arteriolar tortuosity) and moderate NPDR (OR 1.67, 95% CI 1.10-2.55) but not VTDR (OR 0.91, 95% CI 0.54-1.54). No association with DR was found for venular tortuosity.

CONCLUSIONS/INTERPRETATION

Persons with diabetes had more tortuous retinal vasculature than persons without diabetes. In persons with diabetes, increased arteriolar tortuosity was associated with mild and moderate stages of DR. This suggests that retinal vascular tortuosity might be an early indicator of microvascular damage in diabetes; thus, further investigation is indicated.

Immunohistochemical study of stromal and vascular components of tonsillar polyps: high endothelial venules as participants of the polyp's lymphoid tissue

Tonsillar polyps are nonneoplastic lesions usually composed of variable amounts of lymphoid and vascular and connective tissues. All of them are generally assumed to be hamartomatous proliferations, but the profile of vascular and connective components has yet to be explored. The vascular system of the tonsils is complex and includes highly specialized structures (i.e., high endothelial venules (HEVs)) involved in lymphocyte homing into lymphoid tissues. In 14 tonsillar polyps and 26 control tonsils, an immunohistochemical study was performed using CD34 (blood vessels and HEVs), MECA-79 (HEVs), D2-40 (lymphatic vessels), Ki-67, collagens I and III, fibronectin, and tenascin-C. The polyps showed increased total lymphatic area, whereas the number of blood vessels and lymphatics and the blood vascular area did not differ significantly from those of control tonsils. Rare Ki-67+ endothelial cells were found. In the polyps, we detected, possibly for the first time, HEVs amid lymphoid tissue, and that the amount of the latter correlated positively with HEV density. The polyps also presented lesser amounts of fibronectin and collagens I and III than in normal tonsils, which were distributed in a disorganized fashion. Tenascin-C expression was uncommon in the polyps and control tonsils. Tonsillar polyps are composed of disorganized connective tissue and lymphatic channels which can be considered hamartomatous proliferations. However, the lymphoid component is possibly reactive due to its relationship with the HEVs. The highly differentiated phenotype of the HEVs and their complex biology are not in agreement with what would be expected for a component of hamartomatous nature.

Eosinophilic venulitis of colon presenting as ileocecal mass

Reports of eosinophilic infiltration of the colon causing obstruction are few. It is even less common to find associated extensive intestinal venulitis, which is similar to and lumped together with so called Mesenteric Inflammatory Veno-Occlusive Disease (MIVOD) or Self-Limited Intestinal Venulitis. Eosinophilic necrotizing lymphadenitis, such as what we report here, has never been reported in association with this disease. A 41-year-old female presented with cramping lower abdominal pain, hematochezia, nausea, and vomiting. Computed tomography revealed the presence of the mass and thickening of the illeocecal wall. Endoscopy confirmed a cecal mass with surface ulceration suggestive of cecal adenocarcinoma. Patient underwent right hemicolectomy with the clinical and radiologic diagnosis of adenocarcinoma. Microscopic examination of the resected bowel showed an ulcerated mass in the cecum composed of markedly edematous tissue showing transmural eosinophilic infiltration and extensive eosinophilic and lymphocytic venulitis with and without thrombosis. This was associated with a necrotizing lymphadenitis.

IgG4-related skin lesions in a patient with IgG4-related chronic sclerosing dacryoadenitis and sialoadenitis

We describe a 60-year-old man with IgG4-related chronic sclerosing dacryoadenitis and sialoadenitis associated with lymphoplasmacytic and eosinophilic infiltration in erythematous nodules. Physical examination revealed left eye extrusion and small itchy nodules on the scalp and neck. The serum IgG level was 1,570 mg/dL, IgG4 463 mg/dL (29.5%), and IgE 4,554 IU/mL. Lacrimal gland biopsy disclosed prominent infiltrates of IgG4-positive plasma cells and scattered eosinophilic infiltrates with fibrosis, consistent with IgG4-related disease. A skin biopsy of a cutaneous nodule demonstrated that the infiltrated plasma cells around arterioles or venules in the deep dermis and subcutaneous fat tissue were strongly positive for IgG4. Although the swollen lacrimal and parotid gland and itchy subcutaneous erythematous nodules improved rapidly with oral prednisolone at a dose of 20 mg per day, the skin, lacrimal, and parotid lesions deteriorated simultaneously during steroid tapering and improved after increasing the dosage. As skin lesions are easy to biopsy, further study of the skin manifestations of IgG4-related disease will be important in further clarifying the clinical spectrum, pathophysiology and response to therapy of this disorder.