Complement facilitates developmental microglial pruning of astrocyte and vascular networks

Microglia, the resident immune cell of the central nervous system, play a pivotal role in facilitating neurovascular development through mechanisms that are not fully understood. This current work resolves a previously unknown role for microglia in facilitating the developmental pruning of the astrocytic template resulting in a spatially organized retinal vascular bed. Mechanistically, our study identified that local microglial expression of complement (C)3 and C3aR is necessary for the regulation of astrocyte patterning and vascular growth during retinal development. Ablation of retinal microglia, loss of C3 or C3aR reduced developmental pruning and clearance of astrocytic bodies leading to increased astrocyte density leading to altered vascular patterning during retinal vascular development. This data demonstrates that C3/C3aR signaling is an important checkpoint required for the finetuning of vascular density during neuroretinal development.

STK35 Gene Therapy Attenuates Endothelial Dysfunction and Improves Cardiac Function in Diabetes

Diabetic cardiomyopathy (DCM) is characterized by microvascular pathology and interstitial fibrosis that leads to progressive heart failure. The mechanisms underlying DCM pathogenesis remain obscure, and no effective treatments for the disease have been available. In the present study, we observed that STK35, a novel kinase, is decreased in the diabetic human heart. High glucose treatment, mimicking hyperglycemia in diabetes, downregulated STK35 expression in mouse cardiac endothelial cells (MCEC). Knockdown of STK35 attenuated MCEC proliferation, migration, and tube formation, whereas STK35 overexpression restored the high glucose-suppressed MCEC migration and tube formation. Angiogenesis gene PCR array analysis revealed that HG downregulated the expression of several angiogenic genes, and this suppression was fully restored by STK35 overexpression. Intravenous injection of AAV9-STK35 viral particles successfully overexpressed STK35 in diabetic mouse hearts, leading to increased vascular density, suppression of fibrosis in the heart, and amelioration of left ventricular function. Altogether, our results suggest that hyperglycemia downregulates endothelial STK35 expression, leading to microvascular dysfunction in diabetic hearts, representing a novel mechanism underlying DCM pathogenesis. Our study also emerges STK35 is a novel gene therapeutic target for preventing and treating DCM.

Roles of Proliferation and Angiogenesis in Locally Aggressive Biologic Behavior of Ameloblastoma versus Ameloblastic Fibroma

Background: The present study was carried out to evaluate the roles of proliferation and angiogenesis in locally aggressive biologic behavior of ameloblastoma versus ameloblastic fibroma; Methods: 30 formalin-fixed paraffin embedded blocks (15 cases of ameloblastoma & 15 cases of ameloblastic fibroma) were used. To evaluate the proliferation, the tissue sections were stained with AgNORs stain. CD105 was used as immunohistochemical marker of angiogenesis. Quantitative evaluations of AgNORs were performed. The mean vascular density was evaluated as a measure for CD105 protein expression by using image analyzer computer system; Results: The mean number of AgNORs dots per nucleus was significantly higher in ameloblastoma as compared to ameloblastic fibroma. Also, the protein level of CD105 showed positive expression and wide distribution that the mean vascular density was significantly higher in ameloblastoma as compared to ameloblastic fibroma; Conclusion: Quantitative evaluation of AgNORs stain & the mean vascular density utilizing CD105 protein expression may reflect a higher proliferative activity and a more locally aggressive biologic behavior of ameloblastoma when compared to ameloblastic fibroma, that other factors may be involved in biologic behavior of ameloblastic fibroma.

Novel Findings of Retinal and Choroidal Features Utilizing Optical Coherence Tomography Angiography Analysis in Patients With Autoimmune Posterior Uveitis

Purpose: To analyze the quantitative parameters acquired by optical coherence tomography angiography (OCTA) in patients with autoimmune posterior uveitis.Methods: OCTA images of 65 eyes affected with uveitis and 65 normal control (NC) eyes were obtained. The central macular thickness (CMT), retinal thicknesses, foveal avascular zone (FAZ) area, foveal density 300 μm (FD300), and vascular density (VD) were compared among acute uveitic eyes, chronic uveitic eyes, and NC eyes. VDs were evaluated in the choriocapillaris, outer retina, optic disk, whole and parafovea superficial capillary plexus (SCP), and whole and parafovea deep capillary plexus (DCP). Correlation analysis was used to analyze the relationship between LogMAR best-corrected visual acuity (BCVA) and quantitative parameters from OCTA.Results: Compared with NC eyes, the CMT and retinal thicknesses were increased significantly in eyes with uveitis (p < 0.05, respectively). No significant difference was observed in the FAZ area. FD300, VDs in the optic disk, SCP, and DCP both in whole image and parafovea, choriocapillaris were significantly decreased in uveitis eyes (p < 0.05, respectively) compared with NC eyes, only the acute group had decreased VD of the outer retina and choriocapillaris compared with the NC group (p < 0.05). Moreover, quantitative parameters of OCTA showed a significant correlation with LogMAR BCVA in the patients with uveitis. Whole VD DCP was the best predictive factor for BCVA in the patients with uveitis.Conclusion: Quantitative measurement by OCTA is a promising strategy for objective assessment of autoimmune posterior uveitis.

The Action of 2-Aminoethyldiphenyl Borinate on the Pulmonary Arterial Hypertension and Remodeling of High-Altitude Hypoxemic Lambs

Calcium signaling is key for the contraction, differentiation, and proliferation of pulmonary arterial smooth muscle cells. Furthermore, calcium influx through store-operated channels (SOCs) is particularly important in the vasoconstrictor response to hypoxia. Previously, we found a decrease in pulmonary hypertension and remodeling in normoxic newborn lambs partially gestated under chronic hypoxia, when treated with 2-aminoethyldiphenyl borinate (2-APB), a non-specific SOC blocker. However, the effects of 2-APB are unknown in neonates completely gestated, born, and raised under environmental hypoxia. Accordingly, we studied the effects of 2-APB-treatment on the cardiopulmonary variables in lambs under chronic hypobaric hypoxia. Experiments were done in nine newborn lambs gestated, born, and raised in high altitude (3,600 m): five animals were treated with 2-APB [intravenous (i.v.) 10 mg kg–1] for 10 days, while other four animals received vehicle. During the treatment, cardiopulmonary variables were measured daily, and these were also evaluated during an acute episode of superimposed hypoxia, 1 day after the end of the treatment. Furthermore, pulmonary vascular remodeling was assessed by histological analysis 2 days after the end of the treatment. Basal cardiac output and mean systemic arterial pressure (SAP) and resistance from 2-APB- and vehicle-treated lambs did not differ along with the treatment. Mean pulmonary arterial pressure (mPAP) decreased after the first day of 2-APB treatment and remained lower than the vehicle-treated group until the third day, and during the fifth, sixth, and ninth day of treatment. The net mPAP increase in response to acute hypoxia did not change, but the pressure area under the curve (AUC) during hypoxia was slightly lower in 2-APB-treated lambs than in vehicle-treated lambs. Moreover, the 2-APB treatment decreased the pulmonary arterial wall thickness and the α-actin immunoreactivity and increased the luminal area with no changes in the vascular density. Our findings show that 2-APB treatment partially reduced the contractile hypoxic response and reverted the pulmonary vascular remodeling, but this is not enough to normalize the pulmonary hemodynamics in chronically hypoxic newborn lambs.

Study of the retina and optic nerve microvascular bed using optical coherence tomography-angiography in post-COVID-19 patients

Introduction. Signs of angioretinopathy are revealed in 7–27.7 % of post-COVID-19 patients. Optical coherence tomographyangiography (OCT-A) allows performing life-time evaluation of structural and microvascular retinal changes in patients after the new coronavirus infection. Aim. To investigate and to compare main microcirculatory parameters of capillary retinal and optic nerve plexuses using OCT-A in patients after COVID-19 of different severity degree. Materials and methods. The main group consisted of 54 people (108 eyes), who recovered from COVID-19 during 3 preceding months. According to the COVID-19 course severity degree, patients were divided into 3 sub-groups. 22 healthy volunteers (44 eyes) were included in the control group. All patients underwent OCT-A. In the angiography regimen, entire vascular density (VD) and that of every sector in the limits of superficial (SCP) and deep (DCP) capillary plexuses, radial peripapillary capillaries (RPC), and in the foveal avascular zone (FAZ). Results. All over parameters investigated no significant differences between control group patients and those of the sub-group with mild COVID-19 course. In patients with moderately severe infectious process course a significant decrease in VD SCP (P<0.01), as well as decrease in VD RPC (P<0.01). In patients with severe and critically severe disease course there was an decrease of VD DCP in the foveal area (P=0.016) and VD FAZ (P<0.01). VD indices correlations with thickness of retinal layers, in which these vascular plexuses are located. In any of the groups, there was no statistically significant enlargement of the FAZ area and no structural optic disc changes. Conclusion. In post-COVID-19 patients, there are signs of capillary blood flow reduction in retinal SCP and RPC, which is proportional to the prior infection severity degree. Associated to COVID-19 microangiopathy is a significant ophthalmologic sign of the new coronavirus infection. Microvascular changes of the retina could play a role of of a new biomarker reflecting the severity degree of the entire vascular system impairment in COVID-19.

The role of optical coherence tomography angiography biomarkers in assessing the outcome of long-term anti-VEGF therapy of diabetic macular edema

The purpose of the study was to assess the changes of biomarkers of diabetic macular edema activity by optical coherence tomography angiography (OCTA) data and the relationship of these biomarkers with the response to anti-VEGF therapy during a two-year follow-up. Material and methods. The study included 59 patients (101) eyes, averagely aged 60.27 ± 9.50 years. The average number of intravitreal injections of aflibercept over the treatment period was 12.87 ± 3.50. The initial size of the foveolar avascular zone (FAZ) area — 0.37 ± 0.22 mm2 , and the acircularity index — 0.56 ± 0.14 remained unchanged after 5 months: 0.36 ± 0.24 mm2 and 0.56 ± 0.12, respectively, and being practically in the same level in 12 and 24 months. The large FAZ area, noted in the group where disorganization of retinal inner layers (DRIL) was observed (0.39 ± 0.21 mm2 ), correlated with a lower visual acuity (r = 0.67, p = 0.003). The acircularity index remained unchanged; no significant differences were found in the DRIL patient groups. After 5 loading injections, the average initial density of vessels in the macular region increased from 12.33 ± 3.86 mm to 12.75 ± 1.14 mm, after 1 year it was 13.48 ± 1.15 mm, after 2 years — 13.25 ± 3.39 mm. The average density of retinal perfusion increased at the 5th month from 29.81 ± 10.85 % to 31.55 ± 2.34 %, after 12 months to 32.91 ± 3.45, and by the end of the observation period to 31.41 ± 9.79 %. In the DRIL group, the baseline vascular density and mean perfusion volume were significantly lower: 11.17 ± 2.09 mm vs. 13.49 ± 1.14 mm and 28.40 ± 4.53 % vs. 31.20 ± 2.44 %). Conclusion. DRIL, a biomarker reflecting impaired capillary blood flow in the superficial capillary plexus and correlating with functional results, can be used as a predictor of antiangiogenic therapy effectiveness. After antiangiogenic therapy with DMO, the microcirculation indices (FAZ and acircularity) remained stable, and the vascular density and perfusion volume tended to increase, which testifies to the absence of ischemic damage.

Sodium tanshinone IIA sulfonate improves adverse ventricular remodeling post MI by reducing myocardial necrosis, modulating inflammation and promoting angiogenesis

Background and Objective: Myocardial infarction (MI) leads to pathological cardiac remodeling and heart failure. Sodium tanshinone IIA sulfonate (STS) shows therapeutic values. The present study aimed to explore the potential role of STS in ventricular remodeling post-MI Methods: Mice were randomly divided into sham, MI + normal saline (NS) and MI + STS (20.8 mg/kg/day intraperitoneally) groups. MI was established following left anterior descending artery ligation. Cardiac function was evaluated using echocardiography. Scar size and myocardial fibrosis-associated markers were detected using Masson’s trichrome staining and western blot analysis (WB). Necrosis and inflammation were assessed using H&E staining, lactate dehydrogenase (LDH) detection, ELISA, immunohistochemical staining, and WB. Furthermore, angiogenesis markers and associated proteins were detected using immunohistochemical staining and WB. Results: Mice treated with STS exhibited significant improvements in cardiac function, smaller scar size, and low expression levels of α-smooth muscle actin and collagen I and III at 28 days following surgery, compared with the NS-treated group. Moreover, treatment with STS reduced eosinophil necrosis, the infiltration of inflammatory cells, plasma levels of LDH, high mobility group protein B1, interleukin-1β and tumor necrosis factor-α, and protein expression of these cytokines at 3 days. Macrophage infiltration was also decreased in the STS group in the early phase. Additionally, CD31+ vascular density, protein levels of hypoxia-inducible factor-1α, and vascular endothelial growth factor were elevated in the STS-treated mice at 28 days. Conclusion: STS improved pathological remodeling post-MI, and the associated therapeutic effects may result from a decrease in myocardial necrosis, modulation of inflammation, and an increase in angiogenesis.

Decreased retinal microvasculature densities in pterygium

AIM: To investigate the retinal vascular network alterations in eyes of patients with pterygium. METHODS: Totally 18 left eyes from 18 female pterygium patients and 18 left eyes from 18 female healthy control subjects were enrolled. Optical coherence tomography angiography (OCTA) images were generated of the superficial retinal layer and deeper retinal layer of the macular retina for each eye. The microvascular (MIR) and macrovascular (MAR) densities were calculated and MIR, MAR, and total microvascular (TMI) density was compared in the healthy control and pterygium groups. RESULTS: In pterygium group, in the superficial retinal layer, the vascular density in superficial MIR, superior right (SR), inferior right (IR), right (R), superficial central annuli (SC)1, SC2, and SC3 decreased significantly in the macular area (P<0.05). Furthermore, the vascular density in all those decreased regions except R, was significantly and negatively correlated with the disease course (r=-0.6038 to -0.7762, P=0.0008), and the area size of pterygium (r=-0.6043 to -0.9508, P<0.05). For the deeper retinal layer, the density of deep total microvessel (DTMI), deeper MIR, SR, IR, R, DC2, and DC3 decreased significantly in macular area of pterygium patients (P<0.05). Furthermore, the vascular density in all those decreased regions was significantly and negatively correlated with the disease course (r=-0.6901 to -0.7795, P=0.0015), and the area size of pterygium (r=-0.6043 to -0.9563, P<0.05). No statistically significant differences and correlation was found in other region density (|r|<0.47, P>0.05). CONCLUSION: OCTA findings suggest that pterygium patients present with decreased retinal MIR density, and the major vascular alterations occurr mainly on the bitamporal side. The vascular density of the superficial SC1, SC2, SC3 adjacent to the foveal and deep layer of DC2, DC2 regions, significantly decreased.

The 677C>T variant in methylenetetrahydrofolate reductase causes morphological and functional cerebrovascular deficits in mice

Vascular contributions to cognitive impairment and dementia (VCID) particularly Alzheimers disease and related dementias (ADRDs) are increasing; however, mechanisms driving cerebrovascular decline are poorly understood. Methylenetetrahydrofolate reductase (MTHFR) is a critical enzyme in the folate and methionine cycles. Variants in MTHFR, notably 677C>T, are associated with dementias, but no mouse model existed to identify mechanisms by which MTHFR677C>T increases risk. Therefore, MODEL-AD created a novel knock-in (KI) strain carrying the Mthfr677C>T allele on the C57BL/6J background (Mthfr677C>T) to characterize morphology and function perturbed by the variant. Consistent with human clinical data, Mthfr677C>T mice have reduced enzyme activity in the liver and elevated plasma homocysteine levels. MTHFR enzyme activity as well as critical metabolites in the folate and methionine cycles are reduced in the Mthfr677C>T brain. Mice showed reduced tissue perfusion in numerous brain regions by PET/CT as well as significantly reduced vascular density and increased GFAP-expressing astrocytes in frontal cortex . Electron microscopy revealed cerebrovascular damage including endothelial and pericyte apoptosis, reduced luminal size, and increased astrocyte and microglial presence in the microenvironment. Collectively, these data suggest critical perturbations to cerebrovascular function in Mthfr677C>T mice supporting its use as a model for preclinical studies of VCID.