Association between endothelial function and micro-vascular remodeling measured by synchrotron radiation pulmonary micro-angiography in pulmonary arterial hypertension

Assessing radiation-induced carotid artery injury using ultrasound in patients with head and neck cancer

BACKGROUND AND PURPOSE

Radiotherapy (RT) can damage neck vessels in patients with head and neck cancer (HNC). This study investigated the early effects of RT on carotid artery, including the internal media thickness (IMT) and carotid plaques of the common carotid artery (CCA).

MATERIALS AND METHODS

This study included 69 patients with HNC who underwent RT at the First Hospital of Jilin University from March 2017 to September 2022, and 69 healthy participants as controls. Color Doppler ultrasound (CDUS) of the carotid artery was used to measure the CCA IMT and plaques.

RESULTS

Left CCA IMT increased from 0.60 mm (0.60, 0.70) before RT to 0.70 mm (0.60, 1.20) after RT (P < 0.0001). Right CCA IMT changed from 0.60 mm (0.60, 0.71) before RT to 0.60 mm (0.60, 1.10) after RT (P = 0.0002). CCA IMT was 0.60 mm (0.60, 0.70) and 0.80 mm (0.60, 1.20) in the ≤40 Gy and >40 Gy groups (P = 0.0004). The CCA plaques number increased significantly after RT on both the left and right sides (Pleft < 0.0001; Pright <0.0001). The CCA plaques volume increased from 0 mm3 (0, 11.35) and 0 mm3 (0, 8.55) before RT to 8.8 mm3 (0, 21.5) and 5.8 mm3 (0, 16.1) on the left and right sides. Correlation analysis revealed a correlation between CCA IMT and age (r = 0.283, P = 0.001), smoking status (r = 0.179, P = 0.020), and radiation dose (r = 0.188, P = 0.028).

CONCLUSION

RT significantly increased CCA IMT, and the growth was related to the radiation dose. The number and volume of the CCA plaques also increased after RT.

Large-view x-ray imaging for medical applications using the world's only vertically polarized synchrotron radiation beam and a single asymmetric Si crystal

Objective.X-ray microangiography provides detailed information on the internal structure and function of a biological subject. Its ability to evaluate the microvasculature of small animals is useful for acquiring basic and clinical medical knowledge. The following three conditions are necessary to attain detailed knowledge of biological functions: (1) high temporal resolution with sufficient x-ray intensity, (2) high spatial resolution, and (3) a wide field of view. Because synchrotron radiation microangiography systems provide high sapatial resolution and high temporal resolution as a result of their high x-ray intensity, such systems have been developed at various synchrotron radiation facilities, starting with the photon factory, leading to numerous medical discoveries. However, the three aforementioned functions are incompatible with the use of synchrotron radiation because the x-ray intensity decreases when a wide field of view is obtained. To overcome these problems, we developed a new x-ray optical system for microangiography in rats using synchrotron radiation x-rays.Approach.Instead of using monochromatic synchrotron radiation x-rays with a conventional double-crystal monochromator, we used white synchrotron radiation x-rays and an asymmetric Si crystal to simultaneously monochromatize the beam and widen the field of view.Main results.The intensity profile and spatial resolution of the x-ray images were then evaluated. The proposed x-ray optics increased the x-ray intensity and beam width by factors of 1.3 and 2.7, respectively, compared with those of conventional monochromatic x-rays. In addition,in vivostudies on microangiography in rats were performed to confirm that the images had sufficient intensity, spatial resolution, and field of view. One of a series of images taken at 50 ms frame-1was shown as an example.Significance.This x-ray optics provides sufficient x-ray intensity, high spatial resolution, and a wide field of view. This technique is expected providing new insights into the evaluation of the vascular system.

Human Endogenous Retrovirus, SARS-CoV-2, and HIV Promote PAH via Inflammation and Growth Stimulation

Pulmonary arterial hypertension (PAH) is a pulmonary vascular disease characterized by the progressive elevation of pulmonary arterial pressures. It is becoming increasingly apparent that inflammation contributes to the pathogenesis and progression of PAH. Several viruses are known to cause PAH, such as severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), human endogenous retrovirus K(HERV-K), and human immunodeficiency virus (HIV), in part due to acute and chronic inflammation. In this review, we discuss the connections between HERV-K, HIV, SARS-CoV-2, and PAH, to stimulate research regarding new therapeutic options and provide new targets for the treatment of the disease.

Is Willebrand Factor Indicative of Chronic Inflammation in Children with Asthma?

OBJECTIVE

To improve our knowledge and to understand how the level of von Willebrand factor indicates the development of chronic inflammation in children with recurrent wheezing and asthma.

MATERIAL AND METHODS

It was a prospective cohort study. This study was conducted in children with recurrent wheezing and asthma who were referred to a children's hospital during 2017-2018. Patients were divided into 3 groups depending on the number of episodes of wheezing. Patients were examined for von Willebrand factor levels at admission and after treatment. Data analysis was performed with Statsofta Statistica Version 8 (Tulsa, OK).

RESULTS

WF1 levels in Group 2 and 3 children statistically significantly increased in comparison with the control group (p<0.001). WF2 levels remained elevated only in Group 3 patients (p<0.001). WF2 levels in Group 1 and 2 decreased to the indices of the control group (p>0.05). The WF2 significantly decreased after treatment in Group 2 children (p=0.0000, T=0) and Group 3 (p=0.0000, T=0).

CONCLUSION

levels of Willebrand factor indicate the presence of endothelial dysfunction. The level of Willebrand factor in the peak period of wheezing depends on the number of episodes of wheezing in history. Persistent high rates of Willebrand factor, even after the relief of clinical symptoms, indicates the present of chronic inflammation and can be regarded as the formation of asthma in children.

Synchrotron-based phase-contrast micro-CT as a tool for understanding pulmonary vascular pathobiology and the 3-D microanatomy of alveolar capillary dysplasia

This study aimed to explore the value of synchrotron-based phase-contrast microcomputed tomography (micro-CT) in pulmonary vascular pathobiology. The microanatomy of the lung is complex with intricate branching patterns. Tissue sections are therefore difficult to interpret. Recruited intrapulmonary bronchopulmonary anastomoses (IBAs) have been described in several forms of pulmonary hypertension, including alveolar capillary dysplasia with misaligned pulmonary veins (ACD/MPV). Here, we examine paraffin-embedded tissue using this nondestructive method for high-resolution three-dimensional imaging. Blocks of healthy and ACD/MPV lung tissue were used. Pulmonary and bronchial arteries in the ACD/MPV block had been preinjected with dye. One section per block was stained, and areas of interest were marked to allow precise beam-alignment during image acquisition at the X02DA TOMCAT beamline (Swiss Light Source). A ×4 magnifying objective coupled to a 20-µm thick scintillating material and a sCMOS detector yielded the best trade-off between spatial resolution and field-of-view. A phase retrieval algorithm was applied and virtual tomographic slices and video clips of the imaged volumes were produced. Dye injections generated a distinct attenuation difference between vessels and surrounding tissue, facilitating segmentation and three-dimensional rendering. Histology and immunohistochemistry post-imaging offered complementary information. IBAs were confirmed in ACD/MPV, and the MPVs were positioned like bronchial veins/venules. We demonstrate the advantages of using synchrotron-based phase-contrast micro-CT for three-dimensional characterization of pulmonary microvascular anatomy in paraffin-embedded tissue. Vascular dye injections add additional value. We confirm intrapulmonary shunting in ACD/MPV and provide support for the hypothesis that MPVs are dilated bronchial veins/venules.

Aloperine suppresses human pulmonary vascular smooth muscle cell proliferation via inhibiting inflammatory response

Abnormal pulmonary arterial vascular smooth muscle cells (PASMCs) proliferation is critical pathological feature of pulmonary vascular remodeling that acts as driving force in the initiation and development of pulmonary arterial hypertension (PAH), ultimately leading to pulmonary hypertension. Aloperine is a main active alkaloid extracted from the traditional Chinese herbal Sophora alopecuroides and possesses outstanding antioxidation and anti-inflammatory effects. Our group found Aloperine has protective effects on monocroline-induced pulmonary hypertension in rats by inhibiting oxidative stress in previous researches. However, the anti-inflammation effects of Aloperine on PAH remain unclear. Therefore, to further explore whether the beneficial role of Aloperine on PAH was connected with its anti-inflammatory effects, we performed experiments in vitro. Aloperine significantly inhibited the proliferation and DNA synthesis of human pulmonary artery smooth muscle cells (HPASMCs) induced by platelet-derived growth factor-BB, blocked progression through G₀/G₁to S phase of the cell cycle and promoted total ratio of apoptosis. In summary, these results suggested that Aloperine negatively regulated nuclear factor-κB signaling pathway activity to exert protective effects on PAH and suppressed HPASMCs proliferation therefore has a potential value in the treatment of pulmonary hypertension by negatively modulating pulmonary vascular remodeling.

A new method for visualizing pulmonary artery microvasculature using synchrotron radiation pulmonary microangiography: the measurement of pulmonary arterial blood flow velocity in the high pulmonary blood flow rat model

BACKGROUND

Increased pulmonary blood flow (PBF) and shear stress may provoke irreversible vascular remodeling, yet invasive visualization of the microvasculature complicates monitoring. A non-invasive imaging methodology would therefore safely provide mechanistic insights into the progression of high PBF-induced vascular remodeling.

PURPOSE

To establish a novel microvasculature visualization method using synchrotron radiation pulmonary microangiography (SRPA) that can also calculate PBF velocity in vivo.

MATERIAL AND METHODS

A high PBF rat model was established by making a fistula between the abdominal aorta and inferior vena cava. After eight weeks, SRPA was performed and the dynamic density changes in the right lower pulmonary artery (PA) were calculated by software. SRPA was performed with a HARP (High-Gain Avalanche Rushing amorphous Photoconductor) receiver. PBF velocity was calculated by contrast medium transit time within the PA. All data were presented as mean ± standard error (SE). Student's t-test was used for comparison between the two groups.

RESULTS

High dynamic spatial and contrast resolution from SRPA in the PA allowed for clear pulmonary microangiography and accurate detection of higher PBF in the rat model (82.3 ± 8.5 mm/s high-PBF group vs. 46.1 ± 4.3 mm/s control group, P < 0.01).

CONCLUSIONS

These novel results demonstrate that SRPA was useful in both visualizing the dynamic flow distribution within the microvasculature and calculating PBF velocity. This newly developed, non-invasive technology may become a powerful tool in clarifying the mechanism of vascular remodeling associated with high PBF-induced shear stress.

Pulmonary microvascular remodeling in chronic thrombo-embolic pulmonary hypertension

Pulmonary vascular remodeling in pulmonary arterial hypertension involves perturbations in the nitric oxide (NO) and endothelin-1 (ET-1) pathways. However, the implications of pulmonary vascular remodeling and these pathways remain unclear in chronic thrombo-embolic pulmonary hypertension (CTEPH). The objective of the present study was to characterize changes in microvascular morphology and function, focussing on the ET-1 and NO pathways, in a CTEPH swine model. Swine were chronically instrumented and received up to five pulmonary embolizations by microsphere infusion, whereas endothelial dysfunction was induced by daily administration of the endothelial NO synthase inhibitor N^ω-nitro-l-arginine methyl ester until 2 wk before the end of study. Swine were subjected to exercise, and the pulmonary vasculature was investigated by hemodynamic, histological, quantitative PCR, and myograph experiments. In swine with CTEPH, the increased right-ventricular afterload, decreased cardiac index, and mild ventilation-perfusion-mismatch were exacerbated during exercise. Pulmonary microvascular remodeling was evidenced by increased muscularization, which was accompanied by an increased maximal vasoconstriction. Although ET-1-induced vasoconstriction was increased in CTEPH pulmonary small arteries, the ET-1 sensitivity was decreased. Moreover, the contribution of the ET_A receptor to ET-1 vasoconstriction was increased, whereas the contribution of the ET_B receptor was decreased and the contribution of Rho-kinase was lost. A reduction in endogenous NO production was compensated in part by a decreased phosphodiesterase 5 (PDE5) activity resulting in an apparent increased NO sensitivity in CTEPH pulmonary small arteries. These findings suggest that pulmonary microvascular remodeling with a reduced activity of PDE5 and Rho-kinase may contribute to the lack of therapeutic efficacy of PDE5 inhibitors and Rho-kinase inhibitors in CTEPH.

Betaine Attenuates Monocrotaline-Induced Pulmonary Arterial Hypertension in Rats via Inhibiting Inflammatory Response

Background: Pulmonary arterial hypertension (PAH) is characterized by increased pulmonary vascular resistance, leading to right ventricular failure and death. Recent studies have suggested that chronic inflammatory processes are involved in the pathogenesis of PAH. Several studies have demonstrated that betaine possesses outstanding anti-inflammatory effects. However, whether betaine exerts protective effects on PAH by inhibiting inflammatory responses in the lungs needs to be explored. To test our hypothesis, we aimed to investigate the effects of betaine on monocrotaline-induced PAH in rats and attempted to further clarify the possible mechanisms. Methods: PAH was induced by monocrotaline (50 mg/kg) and oral administration of betaine (100, 200, and 400 mg/kg/day). The mean pulmonary arterial pressure, right ventricular systolic pressure, and right ventricle hypertrophy index were used to evaluate the development of PAH. Hematoxylin and eosin staining and Masson staining were performed to measure the extents of vascular remodeling and proliferation in fibrous tissue. Monocyte chemoattractant protein-1 (MCP-1) and endothelin-1 (ET-1) were also detected by immunohistochemical staining. Nuclear factor-κB (NF-κB), tumor necrosis factor alpha (TNF-α), and interleukin-1β (IL-1β) were assessed by Western blot. Results: This study showed that betaine improved the abnormalities in right ventricular systolic pressure, mean pulmonary arterial pressure, right ventricle hypertrophy index, and pulmonary arterial remodeling induced by monocrotaline compared with the PAH group. The levels of MCP-1 and ET-1 also decreased. Western blot indicated that the protein expression levels of NF-κB, TNF-α, and IL-1β significantly decreased (p < 0.01). Conclusion: Our study demonstrated that betaine attenuated PAH through its anti-inflammatory effects. Hence, the present data may offer novel targets and promising pharmacological perspectives for treating monocrotaline-induced PAH.

Simultaneous Imaging of Cerebrovascular Structure and Function in Hypertensive Rats Using Synchrotron Radiation Angiography

Hypertension has a profound influence on the structure and function of blood vessels. Cerebral vessels undergo both structural and functional changes in hypertensive animals. However, dynamic changes of cerebrovasculature and the factors involved in this process are largely unknown. In this study, we explored the dynamic changes of vascular structure in hypertensive rats using novel synchrotron radiation angiography. Twenty-four spontaneously hypertensive rats (SHR) and 24 Sprague–Dawley (SD) rats underwent synchrotron radiation (SR) angiography. Each group had 8 animals. We studied the cerebral vascular changes in SHR over a time period of 3–12-month and performed quantitative analysis. No vascular morphology differences between SHR and SD rats were observed in the early stage of hypertension. The number of twisted blood vessels in the front brain significantly increased at the 9- and 12-month observation time-points in the SHR compared to the SD rats (p < 0.01). The vessel density of the cortex and the striatum in SHR was consistently higher than that in SD rats at time points of 3-, 9-, and 12-month (p < 0.001). Vascular elasticity decreased both in SHR and SD rats with aging. There were statistically significant differences in the relative vascular elasticity of extracranial/intracranial internal carotid artery, middle cerebral artery, posterior cerebral artery and anterior cerebral artery between SHR and SD rats at 12-month (p < 0.01). We concluded that the dynamic vascular alterations detected by SR angiography provided novel imaging data for the study of hypertension in vivo. The longer the course of hypertension was, the more obvious the vascular differences between the SHR and the SD rats became.