NGF/FAK signal pathway is implicated in angiogenesis after acute cerebral ischemia in rats

Angiogenesis after ischemic stroke

Owing to its high disability and mortality rates, stroke has been the second leading cause of death worldwide. Since the pathological mechanisms of stroke are not fully understood, there are few clinical treatment strategies available with an exception of tissue plasminogen activator (tPA), the only FDA-approved drug for the treatment of ischemic stroke. Angiogenesis is an important protective mechanism that promotes neural regeneration and functional recovery during the pathophysiological process of stroke. Thus, inducing angiogenesis in the peri-infarct area could effectively improve hemodynamics, and promote vascular remodeling and recovery of neurovascular function after ischemic stroke. In this review, we summarize the cellular and molecular mechanisms affecting angiogenesis after cerebral ischemia registered in PubMed, and provide pro-angiogenic strategies for exploring the treatment of ischemic stroke, including endothelial progenitor cells, mesenchymal stem cells, growth factors, cytokines, non-coding RNAs, etc.

The factors affecting neurogenesis after stroke and the role of acupuncture

Stroke induces a state of neuroplasticity in the central nervous system, which can lead to neurogenesis phenomena such as axonal growth and synapse formation, thus affecting stroke outcomes. The brain has a limited ability to repair ischemic damage and requires a favorable microenvironment. Acupuncture is considered a feasible and effective neural regulation strategy to improve functional recovery following stroke via the benign modulation of neuroplasticity. Therefore, we summarized the current research progress on the key factors and signaling pathways affecting neurogenesis, and we also briefly reviewed the research progress of acupuncture to improve functional recovery after stroke by promoting neurogenesis. This study aims to provide new therapeutic perspectives and strategies for the recovery of motor function after stroke based on neurogenesis.

Schwann-like cell conditioned medium promotes angiogenesis and nerve regeneration

Vascular network reconstruction plays a pivotal role in the axonal regeneration and nerve function recovery after peripheral nerve injury. Increasing evidence indicates that Schwann cells (SCs) can promote nerve function repair, and the beneficial effects attributed to SCs therapy may exert their therapeutic effects through paracrine mechanisms. Recently, the previous research of our group demonstrated the promising neuroregenerative capacity of Schwann-like cells (SCLCs) derived from differentiated human embryonic stem cell-derived neural stem cells (hESC-NSCs) in vitro. Herein, the effects of SC-like cell conditioned medium (SCLC-CM) on angiogenesis and nerve regeneration were further explored. The assays were performed to show the pro-angiogenic effects of SCLC-CM, such as promoted endothelial cell proliferation, migration and tube formation in vitro. In addition, Sprague-Dawley rats were treated with SCLC-CM after sciatic nerve crush injury, SCLC-CM was conducive for the recovery of sciatic nerve function, which was mainly manifested in the SFI increase, the wet weight ratio of gastrocnemius muscle, as well as the number and thickness of myelin. The SCLC-CM treatment reduced the Evans blue leakage and increased the expression of CD34 microvessels. Furthermore, SCLC-CM upregulated the expressions of p-Akt and p-mTOR in endothelial cells. In conclusion, SCLC-CM promotes angiogenesis and nerve regeneration, it is expected to become a new treatment strategy for peripheral nerve injury.

Platelet microvesicles promote the recovery of neurological function in mouse model of cerebral infarction by inducing angiogenesis

The aim of this study is to investigate the effect of PMVs on mice with ischemic cerebral infarction and its mechanism. Male C57BL/6 mice were selected, and the right focal cortical infarction model was established via cauterization under a microscope and randomly divided into sham operation (Sham) group, normal saline control (Saline) group and platelet microvesicles intervention (PMVs) group. At 1 h after modeling, 5 μL of PMVs (50 μg/mL) or normal saline was injected into the lateral ventricle. The neurological function of mice in each group was evaluated at 1, 3, 7, 14 and 28 d after modeling. After 28 d, the cerebral infarction area was detected via 2,3,5-triphenyltetrazolium chloride (TTC) staining. At 7 and 28 d after modeling, the blood vessel density, proliferation rate of new vessels and encapsulation rate of pericytes were detected via immunofluorescence staining. Moreover, the changes in cerebral cortical blood flow at the infarction side were detected before modeling and at 7 and 28 d after modeling, respectively. Finally, the expressions of proangiogenic factors vascular endothelial growth factor (VEGF), angiopoietin-1 (Ang-1) and N-Cadherin were detected via Western blotting at 3, 7 and 28 d after modeling. PMVs could promote the improvement of neurological function and significantly reduce the cerebral infarction volume in mice with cerebral infarction. PMVs promoted proliferation of new vessels and increased blood vessel density at the infarction edge in mice with cerebral infarction. PMVs could increase the encapsulation rate of pericytes at the infarction edge and improve the permeability of blood-brain barrier in mice with cerebral infarction. PMVs could increase the cerebral cortical blood flow perfusion in mice with cerebral infarction. PMVs could increase proangiogenic factors in brain tissues in mice with cerebral infarction. PMVs could significantly improve the recovery of neurological function in mice with cerebral infarction, which is closely related to the ability of PMVs to promote angiogenesis at the infarction edge. The possible mechanism is that PMVs facilitate angiogenesis after cerebral infarction through promoting the expressions of VEGF, Ang-1 and N-Cadherin. More importantly, the new vessels promoted by PMVs have complete structure and perfect function, and can improve the cerebral blood flow perfusion at the infarction side.

Effect of laser therapy on expression of angio- and fibrogenic factors, and cytokine concentrations during the healing process of human pressure ulcers

Objective: To evaluate the effect of laser irradiation at different wavelengths on the expression of selected growth factors and inflammatory mediators at particular stages of the wound healing process. Methods: Sixty-seven patients were recruited, treated, and analyzed (group A - 940 nm: 17 patients; group B - 808 nm: 18 patients; group C - 658 nm: 16 patients; group D - sham therapy: 17 patients). Patients received a basic treatment, including repositioning and mobilization, air pressure mattress and bed support surfaces, wound cleansing and drug therapy. Additionally, patients received laser therapy once a day, 5 times a week for 1 month in use of a semiconductor lasers (GaAlAs) which emitted a continuous radiation emission at separate wavelengths of 940 nm (group A), 808 nm (group B) and 658 nm (group C). In group D (sham therapy), laser therapy was applied in the same manner, but the device was off during each session (only the applicator was switched on to scan pressure ulcers using none coherent red visible light). Results: The positive changes in the measured serum (IL-2, IL-6 and TNF-α) and wound tissue (TNF-α, VEGF and TGFβ1) parameters appeared to be connected only with the wavelength of 658 nm. The significant change in pro-inflammatory mediator levels [interleukin 2 (IL-2) with p=0.008 and interleukin 6 (IL-6) with p=0.016] was noticed after two weeks of laser therapy. In the other groups, the inflammation was also reduced, but the process was not as marked as in group C. Similarly, in the case of tumor necrosis factor (TNF-α) concentration, where after two weeks of treatment with irradiation at a wavelength of 658 nm, a rapid suppression was observed (p=0.001), whereas in the other groups, these results were much slower and not as obvious. Interestingly, again in the case of group C, the change in TNF-α concentration in wound tissue was most intensive (≈75% reduction), whereas the changes in other groups were not as obvious (≈50% reduction). After irradiation (658 nm), the VEGF expression increased significantly within the first two weeks, and then it decreased and maintained a stable level. In contrast, the TGFβ1 activity remained level, but always higher in comparison to other groups Conclusions: The effective healing of pressure ulcers is connected with laser irradiation at a wavelength of 658 nm. We believe that this effect is related to the inhibition of inflammatory processes in the wound and stimulation of angiogenesis and fibroblast proliferation at this specific radiation (based both on concentration of interleukins and TNF-α serum level and VEGF, TGFβ1, TNF-α activities in wound biopsies). Laser therapy at wavelengths of 940 and 808 nm does not significantly affect the above-mentioned repair processes, which explains its low effectiveness in the treatment of pressure ulcers.