Effects of Hypoxia on Cerebral Microvascular Angiogenesis: Benefits or Damages?

Hypoxia-Induced Inflammation in In Vitro Model of Human Blood-Brain Barrier: Modulatory Effects of the Olfactory Ensheathing Cell-Conditioned Medium

Hypoxia compromises the integrity of the blood-brain barrier (BBB) and increases its permeability, thereby inducing inflammation. Olfactory ensheathing cells (OECs) garnered considerable interest due to their neuroregenerative and anti-inflammatory properties. Here, we aimed to investigate the potential modulatory effects of OEC-conditioned medium (OEC-CM) on the response of human brain microvascular endothelial cells (HBMECs), constituting the BBB, when exposed to hypoxia. HBMECs were utilized to establish the in vitro BBB model. OECs were isolated from mouse olfactory bulbs, and OEC-CM was collected after 48 h of culture. The effect of OEC-CM treatment on the HBMEC viability was evaluated under both normoxic and hypoxic conditions at 6 h, 24 h, and 30 h. Western blot and immunostaining techniques were employed to assess NF-κB/phospho-NF-κB expression. HIF-1α, VEGF-A, and cPLA2 mRNA expression levels were quantified using digital PCR. ELISA assays were performed to measure PGE2, VEGF-A, IL-8 secretion, and cPLA2 specific activity. The in vitro formation of HBMEC capillary-like structures was examined using a three-dimensional matrix system. OEC-CM attenuated pro-inflammatory responses and mitigated the HIF-1α/VEGFA signaling pathway activation in HBMECs under hypoxic condition. Hypoxia-induced damage of the BBB can be mitigated by novel therapeutic strategies harnessing OEC potential.

Improvements in Exercise for Alzheimer's Disease: Highlighting FGF21-Induced Cerebrovascular Protection

Alzheimer's disease (AD) is the most common neurodegenerative disease. Currently, it has shown a trend of earlier onset, with most patients experiencing a progressive decline in cognitive function following the disease's onset, which places a heavy burden on society and family. Since no drug cure for AD exists, exploring new ways for its treatment and prevention has become critical. Early vascular damage is an initial trigger for neuronal injury in AD, underscoring the importance of vascular health in the early stages of the disease. Patients with early AD experience abnormal blood-brain barrier transport of amyloid-β (Aβ) peptides, with excess Aβ being deposited in the cerebral vasculature. The toxic effects of Aβ lead to abnormalities in cerebrovascular structure and function. Fibroblast growth factor21 (FGF21) is an endocrine factor that positively regulates energy homeostasis and glucose-lipid metabolism. Notably, it is one of the effective targets for metabolic disease prevention and treatment. Recent studies have found that FGF21 has anti-aging and vasoprotective effects, with receptors for FGF21 present in the brain. Exercise stimulates the liver to produce large amounts of FGF21, which enters the blood-brain barrier with the blood to exert neurovascular protection. Therefore, we review the biological properties of FGF21, its role in the cerebrovascular structure and function in AD, and the mechanism of exercise-regulated FGF21 action on AD-related cerebrovascular changes, aiming to provide a new theoretical basis for using exercise to ameliorate degenerative neurological diseases.

Protective effects of hypoxic conditioning treatment on brain and cardiac tissues following thoracic aorta occlusion

BACKGROUND

Thoracic aortic ischemia-reperfusion (I/R) injury occurs in clinical scenarios and can lead to damage in organs such as the spinal cord, kidneys, and intestines. Hypoxic postconditioning (HyP) has shown promise in reducing organ I/R injury, suggesting its potential applicability in thoracic aortic I/R injury. However, the pathological damage caused by thoracic aorta occlusion (TAO) to the heart and brain is not yet well understood. This study aims to investigate the protective effects of hypoxic conditioning (HyP) treatment on brain and cardiac tissues following TAO-induced I/R injury.

MATERIALS AND METHODS

Male C57BL/6 mice were used to construct the TAO model by blocking the thoracic aorta for 0.5 or 1 h, followed by 24 h of reperfusion. The mice were divided into five groups: sham, TAO (0.5 h), TAO (0.5 h) +HyP, TAO (1 h), and TAO (1 h) +HyP. Hematoxylin and eosin, Masson, and Sirius red staining were performed to assess morphological changes and collagen deposition in brain and heart tissues. Protein expression assays were conducted to quantify inflammation-related proteins in the serum.

RESULTS

The results showed that TAO caused significant neuronal damage in the hippocampal regions (CA1, CA3, and DG) and myocardial cell damage with collagen deposition. HyP treatment significantly alleviated these damages, particularly with shorter ischemic durations (0.5 h). Specifically, in cardiac tissues, HyP treatment reduced myocardial injury and collagen deposition. In addition, HyP treatment modulated systemic inflammatory responses, as evidenced by the increased expression of anti-inflammatory proteins such as interleukin 13 (IL-13) and the decreased expression of pro-inflammatory proteins such as IL-6, IL-12p70, IL-17, and tumor necrosis factor-α.

CONCLUSION

HyP treatment significantly mitigates brain and cardiac tissue damage caused by TAO, especially with shorter ischemic durations. These findings highlight the potential clinical application of HyP treatment in reducing TAO-induced tissue damage and inflammation, offering a novel therapeutic option for patients with thoracic aortic I/R injury. Future studies should further investigate the mechanisms and optimal implementation protocols of HyP treatment to maximize its clinical value.

Tumoroids, a valid preclinical screening platform for monitoring cancer angiogenesis

In recent years, biologists and clinicians have witnessed prominent advances in in vitro 3D culture techniques related to biomimetic human/animal tissue analogs. Numerous data have confirmed that unicellular and multicellular (tumoroids) tumor spheroids with dense native cells in certain matrices are sensitive and valid analytical tools for drug screening, cancer cell dynamic growth, behavior, etc. in laboratory settings. Angiogenesis/vascularization is a very critical biological phenomenon to support oxygen and nutrients to tumor cells within the deep layer of solid masses. It has been shown that endothelial cell (EC)-incorporated or -free spheroid/tumoroid systems provide a relatively reliable biological platform for monitoring the formation of nascent blood vessels in micron/micrometer scales. Besides, the paracrine angiogenic activity of cells within the spheroid/tumoroid systems can be monitored after being treated with different therapeutic approaches. Here, we aimed to collect recent advances and findings related to the monitoring of cancer angiogenesis using unicellular and multicellular tumor spheroids. Vascularized spheroids/tumoroids can help us in the elucidation of mechanisms related to cancer formation, development, and metastasis by monitoring the main influencing factors.

Stroke-heart syndrome: current progress and future outlook

Stroke can lead to cardiac complications such as arrhythmia, myocardial injury, and cardiac dysfunction, collectively termed stroke-heart syndrome (SHS). These cardiac alterations typically peak within 72 h of stroke onset and can have long-term effects on cardiac function. Post-stroke cardiac complications seriously affect prognosis and are the second most frequent cause of death in patients with stroke. Although traditional vascular risk factors contribute to SHS, other potential mechanisms indirectly induced by stroke have also been recognized. Accumulating clinical and experimental evidence has emphasized the role of central autonomic network disorders and inflammation as key pathophysiological mechanisms of SHS. Therefore, an assessment of post-stroke cardiac dysautonomia is necessary. Currently, the development of treatment strategies for SHS is a vital but challenging task. Identifying potential key mediators and signaling pathways of SHS is essential for developing therapeutic targets. Therapies targeting pathophysiological mechanisms may be promising. Remote ischemic conditioning exerts protective effects through humoral, nerve, and immune-inflammatory regulatory mechanisms, potentially preventing the development of SHS. In the future, well-designed trials are required to verify its clinical efficacy. This comprehensive review provides valuable insights for future research.

An endothelial-related prognostic index for bladder cancer patients

BACKGROUND

Within the tumor microenvironment, endothelial cells hold substantial sway over bladder cancer (BC) prognosis. Herein, we aim to elucidate the impact of endothelial cells on BC patient outcomes by employing an integration of single-cell and bulk RNA sequencing data.

METHODS

All data utilized in this study were procured from online databases. R version 3.6.3 and relevant packages were harnessed for the development and validation of an endothelial-associated prognostic index (EPI).

RESULTS

EPI was formulated, incorporating six genes (CYTL1, FAM43A, GSN, HSPG2, RBP7, and SLC2A3). EPI demonstrated significant prognostic value in both The Cancer Genome Atlas (TCGA) and externally validated dataset. Functional results revealed a profound association between EPI and endothelial cell functionality, as well as immune-related processes. Our findings suggest that patients with low-risk EPI scores are more likely to respond positively to immunotherapy, as indicated by immune checkpoint activity, immune infiltration, tumor mutational burden, stemness index, TIDE, and IMvigor210 analyses. Conversely, individuals with high-risk EPI scores exhibited heightened sensitivity to cisplatin, docetaxel, and gemcitabine treatment regimens.

CONCLUSION

We have effectively discerned pivotal genes from the endothelial cell perspective and constructed an EPI for BC patients, thereby offering promising prospects for precision medicine.

The impact of high-altitude and cold environment on brain and heart damage in rats with hemorrhagic shock

BACKGROUND

Hemorrhagic shock (HS) causes severe organ damage, worsened by high-altitude conditions with lower oxygen and temperatures. Existing research lacks specific insights on brain and heart damage under these conditions. This study hypothesizes that high-altitude and cold (HAC) environments exacerbate HS-induced damage in the brain and heart, aiming to improve treatment strategies.

MATERIALS AND METHODS

Twenty-four male Sprague-Dawley (SD) rats (200-250 g of weight) were randomly assigned into sham, HS + normal, HS + HAC (4,000 m), and HS + HAC (6,000 m). The HS model was established in SD rats (35% loss of total blood volume), and histopathological injuries of the brain and heart were detected using hematoxylin and eosin staining, Sirius red staining, and immunohistochemistry. Apoptosis of the brain and heart tissues was detected by terminal transferase-mediated dUTP nick end labeling (TUNEL) immunofluorescence staining. To determine the levels of tumor necrosis factor-α (TNF-α), interferon-gamma (IFN-γ), monocyte chemoattractant protein-1 (Mcp-1), BCL2-associated X (BAX), and myeloid cell leukemia-1 (Mcl-1) protein, western blotting assay was used.

RESULTS

The HAC environment induced pathological damage to the brain and heart and aggravated the degree of cardiac fibrosis in HS rats. However, it did not cause apoptosis of the brain and heart. In addition, it upregulated TNF-α, IFN-γ, Mcp-1, and BAX protein levels, but downregulated Mcl-1 protein levels (P < 0.05).

CONCLUSIONS

The HAC environment aggravated the degree of brain and heart damage in HS rats, which may be related to neuron nucleus pyknosis, myocardial fibrosis, and inflammatory and apoptosis activation.

Role of cell rearrangement and related signaling pathways in the dynamic process of tip cell selection

Angiogenesis is a complex, highly-coordinated and multi-step process of new blood vessel formation from pre-existing blood vessels. When initiated, the sprouting process is spearheaded by the specialized endothelial cells (ECs) known as tip cells, which guide the organization of accompanying stalk cells and determine the function and morphology of the finally-formed blood vessels. Recent studies indicate that the orchestration and coordination of angiogenesis involve dynamic tip cell selection, which is the competitive selection of cells to lead the angiogenic sprouts. Therefore, this review attempt to summarize the underlying mechanisms involved in tip cell specification in a dynamic manner to enable readers to gain a systemic and overall understanding of tip cell formation, involving cooperative interaction of cell rearrangement with Notch and YAP/TAZ signaling. Various mechanical and chemical signaling cues are integrated to ensure the right number of cells at the right place during angiogenesis, thereby precisely orchestrating morphogenic functions that ensure correct patterning of blood vessels. Video Abstract.