Blood Vessel Regeneration Research Articles

Biphasic Calcium Phosphate Ceramic Scaffold Composed of Zinc Doped β-Tricalcium Phosphate and Silicon Doped Hydroxyapatite for Bone Tissue Engineering.

The rapid repair of bone defects remains a significant clinical challenge to this day. To address this issue, a 3D-printed biphasic calcium phosphate (BCP) scaffold consisting of 40 wt % hydroxyapatite (HA) and 60 wt % β-tricalcium phosphate (β-TCP) was created. Silicon and zinc were incorporated into HA and β-TCP, respectively, to enhance the angiogenic and osteogenic properties of the BCP scaffold. The physicochemical properties, in vitro cell responses, and bone defect repair efficacy of the modified BCP scaffold were comprehensively investigated. Results showed that the fabricated scaffold possessed a 3D interconnected pore structure. Zinc doping enhanced the sintering of the BCP scaffold, increased its density and strength, but decreased its degradation rate. Conversely, silicon doping had the opposite effect. The modified scaffold was capable of a gradual release of zinc/silicon ions, which promoted the proliferation and differentiation of cells. Specifically, the scaffold doped with zinc significantly promoted the osteogenic differentiation of stem cells. Moreover, co-doping with silicon and zinc synergistically promoted in vitro angiogenesis, with BCP-3 (doped with 2.5 mol % zinc and 4 mol % silicon) exhibiting the best pro-angiogenic activity. BCP-3 significantly induced regeneration of blood vessels and bone tissue in vivo, indicating its potential to accelerate the process of bone defect repair.

Increased TRPV4 Channel Expression Enhances and Impairs Blood Vessel Function in Hypertension.

Endothelial cell TRPV4 (transient receptor potential vanilloid 4) channels provide a control point that is pivotal in regulating blood vessel diameter by mediating the Ca2+-dependent release of endothelial-derived vasoactive factors. In hypertension, TRPV4-mediated control of vascular function is disrupted, but the underlying mechanisms and precise physiological consequences remain controversial. Here, using a comprehensive array of methodologies, endothelial TRPV4 channel function was examined in intact mesenteric resistance arteries from normotensive Wistar-Kyoto and spontaneously hypertensive rats. Our results show there is a notable shift in vascular reactivity in hypertension characterized by enhanced endothelium-dependent vasodilation at low levels of TRPV4 channel activation. However, at higher levels of TRPV4 activity, this vasodilatory response is reversed, contributing to the aberrant vascular tone observed in hypertension. The change in response, from dilation to constriction, was accompanied by a shift in intracellular Ca2+ signaling modalities arising from TRPV4 activity. Oscillatory TRPV4-evoked IP3 (inositol triphosphate)-mediated Ca2+ release, which underlies dilation, decreased, while the contraction inducing sustained Ca2+ rise, arising from TRPV4-mediated Ca2+ influx, increased. Our findings also reveal that while the sensitivity of endothelial cell TRPV4 to activation was unchanged, expression of the channel is upregulated and IP3 receptors are downregulated in hypertension. These data highlight the intricate interplay between endothelial TRPV4 channel expression, intracellular Ca2+ signaling dynamics, and vascular reactivity. Moreover, the data support a new unifying hypothesis for the vascular impairment that accompanies hypertension. Specifically, endothelial cell TRPV4 channels play a dual role in modulating blood vessel function in hypertension.

Experimental study on repairing rat abdominal wall defect with chitosan hydrogel/polypropylene mesh composite

To investigate the improvement effects and mechanisms of composite chitosan (CS) hydrogel on traditional polypropylene (PP) mesh for repairing abdominal wall defects. CS hydrogel was prepared via physical cross-linking and then combined with PP mesh to create a CS hydrogel/PP mesh composite. The internal structure and hydrophilicity of the composite were characterized using macroscopic observation, upright metallographic microscope, scanning electron microscopy, and water contact angle measurements. The performance of the composite (experimental group) in resisting cell adhesion and supporting cell infiltration was assessed through fibroblast (NIH-3T3) infiltration experiments and human umbilical vein endothelial cells (HUVECs) tube formation assays, and simple cells were used as control group. Finally, a bilateral abdominal wall defect model (1.5 cm×1.0 cm) was established in 18 Sprague Dawley rats aged 8-10 weeks, with the composite used on one side (experimental group) and PP mesh on the other side (control group). The effects on promoting wound healing, preventing adhesion, angiogenesis, and anti-inflammation were investigated through macroscopic observation, histological staining (HE and Masson staining), and immunohistochemical staining (CD31, CD68). The composite appeared as a pale yellow, transparent solid with a thickness of 2-3 mm, with the PP mesh securely encapsulated within the hydrogel. Scanning electron microscopy revealed that the hydrogel contained interconnected pores measuring 100-300 μm, forming a porous structure. Contact angle measurements indicated that CS hydrogel exhibited good hydrophilicity, while PP mesh was highly hydrophobic. In vitro cell culture experiments showed that DAPI staining indicated fewer positive cells in the experimental group after 1 day of culture, while the cells in control group covered the entire well plate. After 3 days of culture, the cells in experimental group were spherical and displayed uneven fluorescence, suggesting that the material could reduce cell adhesion while supporting cell infiltration. HUVECs tube formation experiments demonstrated an increase in cell numbers in experimental group with a trend towards tube formation, while cells in control group were sparsely distributed and showed no migration. In the rat abdominal wall defect repair experiment, results showed that after 1 week post-surgery, the experimental group had tissue and blood vessels infiltrating, and by 4 weeks, the integrity was well restored with significant regeneration of muscle and blood vessels, while the control group exhibited adhesions and incomplete healing. HE staining results indicated weaker cell infiltration in the experimental group, with cell density significantly higher than that of the control group at 2 and 4 weeks post-surgery ( P<0.05). Masson staining revealed that collagen fibers in the experimental group were arranged neatly, with significantly increased collagen content at 2 weeks post-surgery ( P<0.05), while collagen content was similar in both groups at 4 weeks ( P>0.05). Immunohistochemical staining showed that CD31-positive cells were evenly distributed between muscle layers in the experimental group, whereas the control group exhibited notable defects. At 2 weeks after operation, the CD31-positive cell ratio was significantly higher than that in the control group ( P<0.05); at 2 and 4 weeks after operation, the CD68-positive cell ratio in the experimental group was significantly lower than that in the control group ( P<0.05). CS hydrogel has a positive effect on preventing adhesions and promoting wound healing, exhibiting anti-inflammatory and pro-angiogenic properties during the healing process. This provides a promising strategy to address challenges related to abdominal adhesions and reconstruction.

Poly(L-lactide-co-ɛ-caprolactone)/gelatin-based small-diameter vascular grafts: Salutatory effect of the BVLD and EGCG-Cu to promote hemocompatibility and nitric oxide production for in situ blood vessel regeneration

Polymeric small-diameter vascular grafts (SDVGs, inner diameter, < 6 mm) with characteristics, such as thrombo-protection and adequate short-term as well as long-term patency are still in the development and exploration stage. In this study, based on the gas signaling molecule release strategy, SDVGs were prepared by electrospinning using poly(L-lactide-co-ɛ-caprolactone) (PLCL) and gelatin (Gel). Bivalirudin (BVLD) and epigallocatechin gallate-copper (EGCG-Cu) complex were loaded into SDVGs to improve hemocompatibility and nitric oxide (NO) release, respectively. Vascular grafts manifested drug release for up to 40 days in vitro; BVLD effectively inhibited thrombosis while the EGCG-Cu complex catalyzed the NO production from endogenous donors (S-nitroso glutathione (GSNO) and glutathione (GSH)), thereby conferring vascular grafts with functions similar to that of the natural vascular endothelium layer. Both in vitro and in vivo tests demonstrated that SDVGs co-loaded with BVLD and EGCG-Cu (PG-EB) could effectively inhibit thrombosis, alleviate inflammation, and suppress the proliferation of smooth muscle cells (SMCs) while promoting the proliferation of endothelial cells (ECs), and finally regenerate vascular tissues. In vivo animal experiments demonstrated that vascular grafts could promote endothelialization and vascular remodeling. In summary, our simultaneous utilization of BVLD and EGCG-Cu may offer a promising avenue for the fabrication of in situ regenerable SDVGs.

Overexpression of CGRP receptor attenuates tendon graft degeneration in anterior cruciate ligament reconstruction.

Cell apoptosis or necrosis, extracellular matrix loss, and excessive inflammation may induce tendon graft degeneration. The impairment in the regeneration capability of nerve fibers and blood vessels may be the critical cause. Calcitonin gene-related peptide (CGRP), exhibiting a short half-life, favors cell proliferation, nerve fiber regeneration and angiogenesis. We aimed to investigate the effects of CGRP receptor-mediated signaling on tendon graft integrity and study if the modulation pathways are ascribed to cell proliferation, nerve fiber and blood vessel regeneration. A total of three groups in mice with ACL reconstruction were established: the control group (PBS treatment), the adenovirus vectors expressing CGRP receptor (CALCRL) treated group (Adv-Calcrl treatment), and the adenovirus vectors carrying shRNA targeting Calcrl treated group (Adv-shCalcrl treatment). The histological assessment indicated the Adv-Calcrl treatment was favored while the Adv-shCalcrl significantly impaired tendon graft integrity. TUNEL staining revealed a significant decreased number of apoptotic cells in the Adv-Calcrl group relative to the control group and the adv-shCalcrl group. Compared to the control group and the Adv-shCalcrl group, the Adv-Calcrl group showed significantly enhanced proliferation of nestin positive cells. Of note, the Adv-Calcrl treatment significantly increased EMCN expression at the tendon graft relative to the control and the Adv-shCalcrl groups, which may be ascribed to attenuation of the Hippo signaling pathway. Importantly, the Adv-Calcrl treatment significantly increased sensory nerve fibers and also PIEZO2 levels. Our results demonstrate the activation of CGRP receptor-mediated signaling attenuated tendon graft degeneration, which was ascribed to enhanced proliferation of Nestin positive cells, angiogenesis, and nerve fiber outgrowth.

Highly concentrated collagen/chondroitin sulfate scaffold with platelet-rich plasma promotes bone-exposed wound healing in porcine.

In the case of wounds with exposed bone, it is essential to provide not only scaffolds with sufficient mechanical strength for protection, but also environments that are conducive to the regeneration of tissues and blood vessels. Despite the excellent biocompatibility and biodegradability of collagen and chondroitin sulfate, they display poor mechanical strength and rapid degradation rates. In contrast to previous methodologies that augmented the mechanical properties of biomaterials through the incorporation of additional substances, this investigation exclusively enhanced the mechanical strength of collagen/chondroitin sulfate scaffolds by modulating collagen concentrations. Furthermore, platelet-rich plasma (PRP) was employed to establish optimal conditions for vascular and tissue regeneration at the wound site. High-concentration collagen/chondroitin sulfate (H C-S) scaffolds were synthesized using high-speed centrifugation and combined with PRP, and their effects on endothelial cell proliferation were assessed. A porcine model of bone-exposed wounds was developed to investigate the healing effects and mechanisms. The experimental results indicated that scaffolds with increased collagen concentration significantly enhanced both tensile and compressive moduli. The combination of H C-S scaffolds with PRP markedly promoted endothelial cell proliferation. In vivo experiments demonstrated that this combination significantly accelerated the healing of porcine bone-exposed wounds and promoted vascular regeneration. This represents a promising strategy for promoting tissue regeneration that is worthy of further exploration and clinical application.

VEGFA may be a potential marker of myopic choroidal thickness and vascular density changes

To evaluate the changes of choroidal thickness (CT) and blood flow related to myopia, and its effects of vascular endothelial growth factor (VEGFA) on choroidal vessels in myopia. Subjects were included and divided into emmetropia (EM), non-high myopia (Non-HM) and high myopia (HM) groups. we measured choroidal thickness (CT), choriocapillaris vessel density (VD), and VEGFA content in tears in humans (137 subjects for CT, VD and 84 for tear) and detected the role of VEGFA in the choroid in form-deprivation myopia (FDM) in guinea pigs. Twenty-four guinea pigs were divided into control and FDM groups, and the expression changes of choroidal vessels and VEGFA were observed and compared using immunohistochemistry and Western blotting. Twenty-one guinea pigs were divided into control, FDM + Vehicle and FDM + Conbercept groups. The changes of diopter, axis length and choroidal vessels after intravitreal injection of Conbercept were observed. There were significant differences in CT and VD among the three groups (p < 0.05). VEGFA levels in tears were significantly lower in the myopic groups, with a decreasing trend from EM to Non-HM to HM. The choroidal vascular area fraction of FDM decreased compared to the control group. FDM guinea pigs exhibited reduced choroidal vasculature and significant downregulation of VEGFA expression. Following intravitreal injection of conbercept, the FDM + Conbercept group showed greater myopia, longer axial length, and lower choroidal vascular area fraction compared to the control group. VEGFA may participate in the regulation of choroidal blood vessels and blood flow in the progression of myopia. The reduction in VEGFA may accelerates the progression of myopia.

ERG Regulates Lymphatic Vessel Specification Genes and Its Deficiency Impairs Wound Healing-Associated Lymphangiogenesis.

Rarefaction of blood and lymphatic vessels in the skin has been reported in systemic sclerosis (SSc) (scleroderma). E26 transformation-specific-related factor (ERG) and Friend leukemia virus-induced erythroleukemia 1 (FLI-1) are important regulators of angiogenesis, but their role in lymphatic vasculature is lesser known. The goal of this study was to determine the role of ERG and FLI-1 in postnatal lymphangiogenesis and SSc lymphatic system defects. Immunofluorescence was used to detect ERG and FLI-1 in skin biopsy samples from patients with SSc and healthy controls. Transcriptional analysis of ERG or FLI-1-silenced human dermal lymphatic endothelial cells (LECs) was performed using microarrays. Effects of ERG and FLI-1 deficiency on in vitro tubulogenesis in human dermal LECs were examined using a Matrigel assay. ERG and FLI-1 endothelial-specific knockouts and ERG lymphatic-specific knockouts were generated to examine vessel regeneration in mice. ERG and FLI-1 protein levels were reduced in the blood and lymphatic vasculature in SSc skin biopsy samples. ERG levels were shown to regulate genes involved in lymphatic vessel specification, including vascular endothelial growth factor receptor 3/FLT-4, lymphatic vessel endothelial hyaluronan receptor 1, SOX-18, and prospero homeobox 1 (PROX-1), whereas FLI-1 enhanced the function of ERG. The ERG-FLT-4 pathway regulated in vitro tubulogenesis in human LECs. Deficiency of ERG or FLI-1 similarly impaired the function of blood vessels in mice. However, only ERG deficiency affected the regeneration of lymphatic vessels during wound healing. ERG and FLI-1 are essential regulators of blood and lymphatic vessel regeneration. Deficiency of ERG and FLI-1 in SSc endothelial cells may contribute to the impairment of blood and lymphatic vasculature in patients with SSc.

Photothermal enhanced antibacterial chitosan-based polydopamine composite hydrogel for hemostasis and burn wound repairing

Bleeding and bacterial infection are common problems associated with wound treatment, while effective blood clotting and vessel regeneration promotion are the primary considerations to design the wound dressing materials. This research presents a chitosan-based hydrogel with grafted quaternary ammonium and polyphosphate (QCSP hydrogel) as the antibacterial hemostatic dressing to achieve burn wound treatment. The tissue adhesion of the hydrogel sealed the blood flow and the polyphosphate grafted to the chitosan promoted the activation of coagulation factor V to enhance the hemostasis. At the same time, the grafted quaternary ammonium enhanced the antibacterial ability of the biodegradable hydrogel wound dressing. In addition, the polydopamine as a photothermal agent was composited into the hydrogel to enhance the antibacterial and reactive oxygen scavenging performance. The in vivo hemostasis experiment proved the polyphosphate enhanced the coagulation property. Moreover, this photothermal property of the composite hydrogel enhanced the burn wound repairing rate combined with the NIR stimulus. As a result, this hydrogel could have potential application in clinic as dressing material for hemostasis and infection prone would repairing.

KRIT1 in vascular biology and beyond.

KRIT1 is a 75 kDa scaffolding protein which regulates endothelial cell phenotype by limiting the response to inflammatory stimuli and maintaining a quiescent and stable endothelial barrier. Loss-of-function mutations in KRIT1 lead to the development of cerebral cavernous malformations (CCM), a disease marked by the formation of abnormal blood vessels which exhibit a loss of barrier function, increased endothelial proliferation, and altered gene expression. While many advances have been made in our understanding of how KRIT1, and the functionally related proteins CCM2 and PDCD10, contribute to the regulation of blood vessels and the vascular barrier, some important open questions remain. In addition, KRIT1 is widely expressed and KRIT1 and the other CCM proteins have been shown to play important roles in non-endothelial cell types and tissues, which may or may not be related to their role as pathogenic originators of CCM. In this review, we discuss some of the unsettled questions regarding the role of KRIT1 in vascular physiology and discuss recent advances that suggest this ubiquitously expressed protein may have a role beyond the endothelial cell.

The Protective Effect of Flavonoids in the Diet on Autophagy-Related Cardiac Impairment.

The compounds known as flavonoids, commonly found in fruits, vegetables, legumes, medicinal herbs, chocolate, and coffee and tea beverages, have been extensively researched for their impact on cardiovascular health. Flavonoids, with their demonstrated potential, have shown promising effects in regulating blood vessel function and apoptotic processes, as well as in improving lipid profiles. While their powerful antioxidant properties were initially thought to be the main reason behind these effects, recent studies have uncovered new insights into the positive effects of flavonoids on cardiovascular health, and researchers have now identified several signaling pathways and mechanisms that also play a role. Of particular interest are the studies that have highlighted the role of autophagy in maintaining the physiological functions of cardiomyocytes and protecting them from harm. Recent publications have linked the dysregulation of autophagic processes with the development of cardiomyopathies, heart failure, and other cardiovascular diseases. This review aims to present the latest, novel findings from preclinical research regarding the potential beneficial effects of flavonoids on various heart conditions associated with altered autophagy processes.

Octopus‐Inspired Adaptive Molecular Motion for Synergistic Photothermal and Nitric Oxide Antibacterial Therapy in Diabetic Wound Repair

AbstractBacterial infections, especially those from drug‐resistant strains, pose a significant threat to healing diabetic skin injuries, with current treatments being intricated and often unsatisfactory. Inspired by octopuses, a biomimetic material using α‐cyclodextrin (α‐CD) and polyethylene glycol (PEG) assembled with graphene oxide end‐capped polyrotaxanes (GO‐PR) is developed, where α‐CD mimics the flexible tentacles of an octopus. Further, α‐CD is cationically modified with polyethyleneimine (PEI) to resemble octopus suction cups, creating GO‐PRP, which effectively captures and adheres to bacteria. Importantly, to emulate an octopus's ink defense, GO‐PRP is used as a carrier for nitric oxide (NO), resulting in GO‐PRP/NONOate. Utilizing the photothermal conversion of GO, near‐infrared light exposure triggers rapid heating and NO release, providing efficient antibacterial activity and biofilm dispersion, significantly reducing inflammation in diabetic skin injuries in type I rats. During wound healing, sustained NO release promotes vascular endothelial growth factor production and blood vessel regeneration, enhancing collagen formation and shortening the healing time for diabetic skin infections. Thus, octopus‐inspired GO‐PRP/NONOate emerges as a novel biomaterial for treating drug‐resistant bacterial infections in diabetic wounds in the biomedical field.

Carboxymethyl chitosan-methacrylic acid gelatin hydrogel for wound healing and vascular regeneration

At present, wound dressings in clinical applications are primarily used for superficial skin wounds. However, these dressings have significant limitations, including poor biocompatibility and limited ability to promote wound healing. To address the issue, this study used aldehyde polyethylene glycol as the cross-linking agent to design a carboxymethyl chitosan-methacrylic acid gelatin hydrogel with enhanced biocompatibility, which can promote wound healing and angiogenesis. The CSDG hydrogel exhibits acid sensitivity, with a swelling ratio of up to 300%. Additionally, it exhibited excellent resistance to external stress, withstanding pressures of up to 160 kPa and self-deformation of 80%. Compared to commercially available chitosan wound gels, the CSDG hydrogel demonstrates excellent biocompatibility, antibacterial properties, and hemostatic ability. Both in vitro and in vivo results showed that the CSDG hydrogel accelerated blood vessel regeneration by upregulating the expression of CD31, IL-6, FGF, and VEGF, thereby promoting rapid healing of wounds. In conclusion, this study successfully prepared the CSDG hydrogel wound dressings, providing a new approach and method for the development of hydrogel dressings based on natural macromolecules.

Advanced biomedical and electronic dual-function skin patch created through microfluidic-regulated 3D bioprinting

Artificial skin involves multidisciplinary efforts, including materials science, biology, medicine, and tissue engineering. Recent studies have aimed at creating skins that are multifunctional, intelligent, and capable of regenerating tissue. In this work, we present a specialized 3D printing ink composed of polyurethane and bioactive glass (PU-BG) and prepare dual-function skin patch by microfluidic-regulated 3D bioprinting (MRBP) technique. The MRBP endows the skin patch with a highly controlled microstructure and superior strength. Besides, an asymmetric tri-layer is further constructed, which promotes cell attachment and growth through a dual transport mechanism based on hydrogen bonds and gradient structure from hydrophilic to superhydrophilic. More importantly, by combining the features of biomedical skin with electronic skin (e-skin), we achieved a biomedical and electronic dual-function skin patch. In vivo experiments have shown that this skin patch can enhance hemostasis, resist bacterial growth, stimulate the regeneration of blood vessels, and accelerate the healing process. Meanwhile, it also mimics the sensory functions of natural skin to realize signal detection, where the sensitivity reached up to 5.87 kPa−1, as well as cyclic stability (over 500 cycles), a wide detection range of 0–150 kPa, high pressure resolution of 0.1 % under the pressure of 100 kPa. This work offers a versatile and effective method for creating dual-function skin patches and provide new insights into wound healing and tissue repair, which have significant implications for clinical applications.

Promotion and monitor wound healing by anthocyanin enhanced light curing ε-poly-l-lysine hydrogel encapsulated Cu-MOF

Drug-resistant bacterial infections and biofilm formation have long posed significant challenges to public health, particularly in the context of chronic wound healing. In this study, the CuHspMOF were derived from copper and hesperitin (Hsp). The photocurable Epsilon-poly-l-lysine (EPLMA) and blueberry anthocyanin (BA) were synthesized through free radical polymerization. The multifunctional EB@CuHsp hydrogel exhibits excellent photothermal effect. One of the key features of the EB@CuHsp hydrogel is its ability to monitor the healing environment through color changes in response to variations in pH. This property allows for real-time assessment of the wound’s pH levels, reflecting the body fluid’s pH range during the healing process (pH 5–9). The hydrogel components work synergistically to facilitate wound healing. The EPLMA, with its positively charged, could captures bacteria and enable copper ions to eradicate bacteria at lower concentrations. This dual action leads to the creation of an optimal healing environment conducive to wound healing. During the inflammatory phase, BA and Hsp could collaborate to combat inflammation, which transited from the inflammatory stage to the proliferative phase soon. Continuous release of BA and Cu2+, coupled with thermotherapy, significantly enhances epithelial and blood vessel regeneration, thereby expediting the healing of chronic wounds. Overall, this multifunctional composite hydrogel holds great promise for promoting the regeneration of infected wound tissue, making it a potential candidate for chronic wound dressings.

The influence of the prolactin/vasoinhibin axis on post-stroke lesion volume, astrogliosis, and survival.

Ischemic stroke is a significant global health issue, ranking fifth among all causes of death and a leading cause of serious long-term disability. Ischemic stroke leads to severe outcomes, including permanent brain damage and neuronal dysfunction. Therefore, decreasing and preventing neuronal injuries caused by stroke has been the focus of therapeutic research. In recent years, many studies have shown that fluctuations in hormonal levels influence the prognosis of ischemic stroke. Thus, it is relevant to understand the role of hormones in the pathophysiological mechanisms of ischemic stroke for preventing and treating this health issue. Here, we investigate the contribution of the prolactin/vasoinhibin axis, an endocrine system regulating blood vessel growth, immune processes, and neuronal survival, to the pathophysiology of ischemic stroke. Male mice with brain overexpression of prolactin or vasoinhibin by adeno-associated virus (AAV) intracerebroventricular injection or lacking the prolactin receptor (Prlr-/-) were exposed to transient middle cerebral artery occlusion (tMCAO) for 45 min followed by 48 h of reperfusion. Overexpression of vasoinhibin or the absence of the prolactin receptor led to an increased lesion volume and decreased survival rates in mice following tMCAO, whereas overexpression of prolactin had no effect. In addition, astrocytic distribution in the penumbra was altered, glial fibrillary acidic protein and S100b mRNA expressions were reduced, and interleukin-6 mRNA expression increased in the ischemic hemisphere of mice overexpressing vasoinhibin. Of note, prolactin receptor-null mice (Prlr-/-) showed a marked increase in serum vasoinhibin levels. Furthermore, vasoinhibin decreased astrocyte numbers in mixed hippocampal neuron-glia cultures. These observations suggest that increased vasoinhibin levels may hinder astrocytes' protective reactivity. Overall, this study suggests the involvement of the prolactin/vasoinhibin axis in the pathophysiology of ischemic stroke-induced brain injury and provides insights into the impact of its dysregulation on astrocyte reactivity and lesion size. Understanding these mechanisms could help develop therapeutic interventions in ischemic stroke and other related neurological disorders.

#2382 Renal tubule-derived EVs carrying complement 3 aggravate CKD vascular calcification by downregulating autophagy in vascular smooth muscle cells

Abstract Background and Aims Vascular calcification (VC) is a serious complication of chronic kidney disease (CKD) patients, recognized in KDIGO guidelines as a leading risk factor for cardiovascular diseases. Despite acknowledgment, the mechanisms of VC in CKD remain unclear. The kidneys intricately regulate blood vessel pathophysiology. Clinical studies suggest a correlation between elevated blood complement levels in CKD and arterial calcification, hinting at complement involvement in CKD-associated VC. Renal-origin complement, a significant source of circulating complement, activates in CKD. Extracellular vesicles (EVs), mediating intercellular communication, transport complement-related proteins in various physiological and pathological processes. Studies suggest that plasma EV rather than EV-depleted plasma causes pathogenic calcium salt deposition in smooth muscle cells. This study explores how renal-origin EVs carrying complement mediate CKD-associated VC. Method From October 2021 to August 2023, data from 110 clinical patients were gathered, encompassing both blood C3 levels and CT images of the thoracic aorta. Subsequently, we conducted a scoring analysis of the CT images and carried out correlation analyses. A CKD-associated VC model was induced by feeding C57BL/6j mice an adenine and high-phosphate diet for 16 weeks. Techniques, including WB, PCR, and immunofluorescence, detected complement activation and localization in renal tissues. EVs were isolated from kidney tissue and plasma and identified by NTA, electron microscopy, WB, etc. WB examined C3 and tubular markers of EVs. At the same time, the Elisa method was used to detect C3 in plasma, plasma EV, and EV-depleted plasma. Immunofluorescence investigated tubular-derived EVs uptake in calcified arteries. Tubular-derived EVs, C3a, C3aR receptor inhibitors (SB290157), and autophagy inhibitors (3-MA) intervened in high-phosphate-induced vascular smooth muscle cells (VSMCs). PCR and WB assessed calcification indicators, complement receptors, and autophagy-related indicators. Alizarin Red staining observed calcification nodules. Transcriptome sequencing was performed on control, high-phosphate, and renal tubular-derived EV intervention groups of VSMCs. An in vivo model infused renal tubular-derived EVs and injected C3aR inhibitors and autophagy inhibitors, measuring complement activation and VC indicators. Results There is a correlation between C3 and thoracic aorta calcium score in CKD patients, with a correlation coefficient of 0.3750 (P &amp;lt; 0.01). The CKD-associated VC mice model revealed complement C3 activation in renal tubules, secreted into the blood through EVs. The C3 proportion of plasma EV in CKD patients was significantly higher than that in the control group, but there was no statistical difference between the EV-depleted plasma control group and the CKD group. Immunofluorescence indicated tubular-derived EV uptake by the calcified vascular wall. In vitro, tubular-derived EVs enhanced VSMC osteogenic differentiation and upregulated C3aR, mimicking C3a intervention effects. C3aR receptor inhibitors produced opposing effects. Transcriptome sequencing suggested renal tubular-derived EVs downregulated VSMC autophagy-related pathways; in vitro autophagy inhibition reversed osteogenic differentiation. In vivo, reinfusing renal tubular-derived EVs exacerbated complement activation and VC, while injecting C3aR inhibitors and autophagy inhibitors alleviated CKD-associated VC. Conclusion This study confirms that tubular-derived EVs carrying C3 downregulate autophagy in VSMCs, mediating CKD-associated VC. These findings provide insights into understanding CKD-associated VC initiation and progression, revealing potential therapeutic targets.

Life at the crossroads: the nuclear LINC complex and vascular mechanotransduction.

Vascular endothelial cells line the inner surface of all blood vessels, where they are exposed to polarized mechanical forces throughout their lifespan. Both basal substrate interactions and apical blood flow-induced shear stress regulate blood vessel development, remodeling, and maintenance of vascular homeostasis. Disruption of these interactions leads to dysfunction and vascular pathologies, although how forces are sensed and integrated to affect endothelial cell behaviors is incompletely understood. Recently the endothelial cell nucleus has emerged as a prominent force-transducing organelle that participates in vascular mechanotransduction, via communication to and from cell-cell and cell-matrix junctions. The LINC complex, composed of SUN and nesprin proteins, spans the nuclear membranes and connects the nuclear lamina, the nuclear envelope, and the cytoskeleton. Here we review LINC complex involvement in endothelial cell mechanotransduction, describe unique and overlapping functions of each LINC complex component, and consider emerging evidence that two major SUN proteins, SUN1 and SUN2, orchestrate a complex interplay that extends outward to cell-cell and cell-matrix junctions and inward to interactions within the nucleus and chromatin. We discuss these findings in relation to vascular pathologies such as Hutchinson-Gilford progeria syndrome, a premature aging disorder with cardiovascular impairment. More knowledge of LINC complex regulation and function will help to understand how the nucleus participates in endothelial cell force sensing and how dysfunction leads to cardiovascular disease.

Phosphodiesterase 5A regulates the vomeronasal pump in mice.

The vomeronasal organ (VNO) is a specialized chemoreceptive structure in many vertebrates that detects chemical stimuli, mostly pheromones, which often elicit innate behaviors such as mating and aggression. Previous studies in rodents have demonstrated that chemical stimuli are actively transported to the VNO via a blood vessel-based pumping mechanism, and this pumping mechanism is necessary for vomeronasal stimulation in behaving animals. However, the molecular mechanisms that regulate the vomeronasal pump remain mostly unknown. In this study, we observed a high level of expression of phosphodiesterase 5A (PDE5A) in the vomeronasal blood vessel of mice. We provided evidence to support the potential role of PDE5A in vomeronasal pump regulation. Local application of PDE5A inhibitors-sildenafil or tadalafil-to the vomeronasal organ (VNO) reduced stimulus delivery into the VNO, decreased the pheromone-induced activity of vomeronasal sensory neurons, and attenuated male-male aggressive behaviors. PDE5A is well known to play a role in regulating blood vessel tone in several organs. Our study advances our understanding of the molecular regulation of the vomeronasal pump.

DPSCs regulate epithelial-T cell interactions in oral submucous fibrosis

BackgroundOral submucous fibrosis (OSF) is a precancerous lesion characterized by fibrous tissue deposition, the incidence of which correlates positively with the frequency of betel nut chewing. Prolonged betel nut chewing can damage the integrity of the oral mucosal epithelium, leading to chronic inflammation and local immunological derangement. However, currently, the underlying cellular events driving fibrogenesis and dysfunction are incompletely understood, such that OSF has few treatment options with limited therapeutic effectiveness. Dental pulp stem cells (DPSCs) have been recognized for their anti-inflammatory and anti-fibrosis capabilities, making them promising candidates to treat a range of immune, inflammatory, and fibrotic diseases. However, the application of DPSCs in OSF is inconclusive. Therefore, this study aimed to explore the pathogenic mechanism of OSF and, based on this, to explore new treatment options.MethodsA human cell atlas of oral mucosal tissues was compiled using single-cell RNA sequencing to delve into the underlying mechanisms. Epithelial cells were reclustered to observe the heterogeneity of OSF epithelial cells and their communication with immune cells. The results were validated in vitro, in clinicopathological sections, and in animal models. In vivo, the therapeutic effect and mechanism of DPSCs were characterized by histological staining, immunohistochemical staining, scanning electron microscopy, and atomic force microscopy.ResultsA unique epithelial cell population, Epi1.2, with proinflammatory and profibrotic functions, was predominantly found in OSF. Epi1.2 cells also induced the fibrotic process in fibroblasts by interacting with T cells through receptor-ligand crosstalk between macrophage migration inhibitory factor (MIF)-CD74 and C-X-C motif chemokine receptor 4 (CXCR4). Furthermore, we developed OSF animal models and simulated the clinical local injection process in the rat buccal mucosa using DPSCs to assess their therapeutic impact and mechanism. In the OSF rat model, DPSCs demonstrated superior therapeutic effects compared with the positive control (glucocorticoids), including reducing collagen deposition and promoting blood vessel regeneration. DPSCs mediated immune homeostasis primarily by regulating the numbers of KRT19 + MIF + epithelial cells and via epithelial-stromal crosstalk.ConclusionsGiven the current ambiguity surrounding the cause of OSF and the limited treatment options available, our study reveals that epithelial cells and their crosstalk with T cells play an important role in the mechanism of OSF and suggests the therapeutic promise of DPSCs.