Vascular Recovery Research Articles

Reliability of a portable toe pressure photoplethysmography device compared to a stationary laser doppler flowmeter.

The study aimed to investigate the reliability of a portable toe pressure (TP) photoplethysmography device (PPG) by comparing it to a stationary laser Doppler flowmeter (LD) used in the Helsinki University Hospital. The study evaluated if lower limb arterial circulation could be reliably evaluated with the portable PPG which is more affordable and mobile than the stationary LD. TPs were measured from 102 toes of 54 patients in the vascular surgery outpatient clinic, vascular surgery ward and interventional radiology recovery ward of Helsinki University Hospital. According to the study protocol TPs were measured twice with the PPG device. If the difference between the values was over 10 mmHg, a third measurement was done and two of the closest values were selected for the final analysis. The lowest value displayed by the PPG device was 30 mmHg. Lower than 30 mmHg values were reported as 25 mmHg in the analysis. The repeatability and reliability of the PPG measurements were compared to the LD with Bland Altman plots. Most patients had rest pain (n = 29) or claudication (n = 9). Prior to TP measurement, 24 patients had undergone lower limb revascularization through either a hybrid (n = 3), open (n = 10) or endovascular (n = 11) procedure. The mean absolute difference between PPG and LD measurement values was 15 mmHg (95% confidence interval 12-18 mmHg). 87.5% of lower limbs with significant arterial insufficiency (TP <60 mmHg with LD, n = 49) had a PPG measurement value of <60 mmHg. Conversely, 84.8% of lower limbs that did not exceed the ischemia criterion of TP ≥60 mmHg with LD had a PPG measurement value of ≥60 mmHg. Mean absolute difference of two consecutive PPG measurement values was 4 mmHg (95% CI 3-5 mmHg). The PPG device is a light and affordable option for the assessment of lower limb arterial circulation in primary health care. It is moderately reliable to exclude significant lower limb arterial insufficiency and may reduce unnecessary referrals to the vascular surgery clinic. The repeatability of the PPG device is satisfactory. However, it requires training to use, and the results must always be interpreted with consideration for the patient's clinical status.

Microglia overexpressing brain-derived neurotrophic factor promote vascular repair and functional recovery in mice after spinal cord injury.

Spinal cord injury represents a severe form of central nervous system trauma for which effective treatments remain limited. Microglia is the resident immune cells of the central nervous system, play a critical role in spinal cord injury. Previous studies have shown that microglia can promote neuronal survival by phagocytosing dead cells and debris and by releasing neuroprotective and anti-inflammatory factors. However, excessive activation of microglia can lead to persistent inflammation and contribute to the formation of glial scars, which hinder axonal regeneration. Despite this, the precise role and mechanisms of microglia during the acute phase of spinal cord injury remain controversial and poorly understood. To elucidate the role of microglia in spinal cord injury, we employed the colony-stimulating factor 1 receptor inhibitor PLX5622 to deplete microglia. We observed that sustained depletion of microglia resulted in an expansion of the lesion area, downregulation of brain-derived neurotrophic factor, and impaired functional recovery after spinal cord injury. Next, we generated a transgenic mouse line with conditional overexpression of brain-derived neurotrophic factor specifically in microglia. We found that brain-derived neurotrophic factor overexpression in microglia increased angiogenesis and blood flow following spinal cord injury and facilitated the recovery of hindlimb motor function. Additionally, brain-derived neurotrophic factor overexpression in microglia reduced inflammation and neuronal apoptosis during the acute phase of spinal cord injury. Furthermore, through using specific transgenic mouse lines, TMEM119, and the colony-stimulating factor 1 receptor inhibitor PLX73086, we demonstrated that the neuroprotective effects were predominantly due to brain-derived neurotrophic factor overexpression in microglia rather than macrophages. In conclusion, our findings suggest the critical role of microglia in the formation of protective glial scars. Depleting microglia is detrimental to recovery of spinal cord injury, whereas targeting brain-derived neurotrophic factor overexpression in microglia represents a promising and novel therapeutic strategy to enhance motor function recovery in patients with spinal cord injury.

Spinal Cord Blood Perfusion Deficit is Associated with Clinical Impairment after Spinal Cord Injury.

Spinal cord injury (SCI) results in intramedullary microvasculature disruption and blood perfusion deficit at and remote from the injury site. However, the relationship between remote vascular impairment and functional recovery remains understudied. We characterized perfusion impairment invivo, rostral to the injury, using magnetic resonance imaging (MRI), and investigated its association with lesion extent and impairment following SCI. Twenty-one patients with chronic cervical SCI and 39 healthy controls (HC) underwent a high-resolution MRI protocol, including intravoxel incoherent motion (IVIM) and T2*-weighted MRI covering C1-C3 cervical levels, as well as T2-weighted MRI to determine lesion volumes. IVIM matrices (i.e., blood volume fraction, velocity, flow indices, and diffusion) and cord structural characteristics were calculated to assess perfusion changes and cervical cord atrophy, respectively. Patients with SCI additionally underwent a standard clinical examination protocol to assess functional impairment. Correlation analysis was used to investigate associations between IVIM parameters with lesion volume and sensorimotor dysfunction. Cervical cord white and gray matter were atrophied (27.60% and 21.10%, p < 0.0001, respectively) above the cervical cord injury, accompanied by a lower blood volume fraction (-22.05%, p < 0.001) and a higher blood velocity-related index (+38.72%, p < 0.0001) in patients with SCI compared with HC. Crucially, gray matter remote perfusion deficit correlated with larger lesion volumes and clinical impairment. This study shows clinically eloquent perfusion deficit rostral to a SCI, its magnitude driven by injury severity. These findings indicate trauma-induced widespread microvascular alterations beyond the injury site. Perfusion MRI matrices in the spinal cord hold promise as biomarkers for monitoring treatment effects and dynamic changes in microvasculature integrity following SCI.

Curdlan-Mediated Syngeneic RNAi against NF-κB in Glial Cells Protects Cerebral Vessels in the TBI Mouse Model.

Traumatic brain injury (TBI) activates the NF-κB pathway in microglia and astrocytes, which secrete pro-inflammatory cytokines that disrupt the blood-brain barrier (BBB). Curdlan derivatives are promising carriers for the delivery of siRNA drugs. Herein, we evaluated the glial cell specificity, siRNA delivery efficiency, and the subsequent phenotypic regulation of glial cells by the Curdlan derivatives in the TBI mouse model. Our in vitro and in vivo studies confirmed that the (1) pAVC4 or CuMAN polymer encapsulating siRNA were internalized by astrocytes and microglia in a receptor-dependent manner; (2) systemic administration of the pAVC4 or CuMAN polymer encapsulating siRNA resulted in significant gene silencing efficiency, altered the phenotypic polarization of glial cells, and regulated the secretion of inflammatory cytokines; (3) this lessened neuroinflammation, ameliorated BBB destruction, and improved vascular recovery. These data suggested that pAVC4 and CuMAN polymers are promising RNA delivery vehicles that can efficiently deliver siRNA to the target cells.

5-Hydroxytryptamine 1F Receptor Agonist Lasmiditan Differentially Regulates Successful Repair and Failed Repair Genes in a Mouse Model of Acute Kidney Injury.

Increasing evidence substantiates the role of mitochondrial dysfunction, inflammation, fibrosis, and cell senescence in the onset and progression of acute kidney injury (AKI) to chronic kidney disease . The underlying governing cellular and transcriptional events, however, are not fully understood. Recently, the key factors that regulate successful and failed repair states in the proximal tubule have been identified at a single-cell resolution following bilateral ischemia-reperfusion (I/R) in a mouse model of AKI. Previously, our group showed that treatment with the FDA-approved selective 5-hydroxytryptamine receptor 1F agonist lasmiditan following AKI induces mitochondrial biogenesis , restores renal mitochondrial function, and increases renal and vascular recovery in vivo. Here, we assessed the effect of lasmiditan on transcriptional and translational changes that are responsible for successful repair, injury, and failed repair states in the renal cortex following I/R-induced AKI. Increased levels of successful repair genes such as acyl-coA synthase medium-chain family member 2a, low-density lipoprotein receptor-related protein 2, solute carrier family 5 member 12, and hepatocyte nuclear factor 4 alpha were observed with 6 and 12 days of lasmiditan treatment following AKI compared to vehicle control. While 6 days of lasmiditan treatment had no effect on failed repair genes, the administration of lasmiditan for 12 days decreased the levels of vascular cell adhesion protein 1, tumor necrosis factor α, and interleukin-1β, which drive maladaptive repair. These data reveal that lasmiditan treatment post-AKI differentially regulates successful and failed repair gene expression in the renal cortex, likely contributing to the restoration of renal function and providing a potential targeted therapeutic pathway for the treatment of AKI.

Insulin-like growth factor-2 mRNA-binding protein 2 facilitates post-ischemic angiogenesis by increasing the stability of fibroblast growth factor 2 mRNA and its protein expression

BackgroundPost-ischemic angiogenesis is crucial for reestablishing blood flow in conditions such as peripheral artery disease (PAD). The role of insulin-like growth factor-2 mRNA-binding protein 2 (IGF2BP2) in post-transcriptional RNA metabolism and its involvement in post-ischemic angiogenesis remains unclear. MethodsUsing a human GEO database and a hind-limb ischemia (HLI) mouse model, the predominant isoform IGF2BP2 in ischemic gastrocnemius tissue was identified. Adeno-associated virus with the Tie1 promoter induced IGF2BP2 overexpression in the HLI model, evaluating the expression of vascular structural proteins (CD31 and α-SMA) and blood flow recovery after HLI. In vitro experiments with human umbilical vein endothelial cells (HUVECs) demonstrated that lentivirus-mediated IGF2BP2 overexpression upregulates cell proliferation, migration, and tube formation. GeneCards, RNAct databases, and subsequent reverse transcription quantitative polymerase chain reaction (RT-qPCR) predicted IGF2BP2 interactions with fibroblast growth factor 2 (FGF2) mRNA, and actinomycin D treatment, binding site predictions and CLIP-seq data further confirmed this interaction. Furthermore, western blotting, enzyme-linked immunosorbent assay, and RNA immunoprecipitation followed by RT-qPCR were performed to validate IGF2BP2's interaction with FGF2 mRNA and to assess its role in stabilizing FGF2 mRNA, as well as its impact on FGF2 protein expression. ResultsHLI reduced IGF2BP2 expression in the gastrocnemius tissue, which gradually increased during blood flow recovery. IGF2BP2 overexpression in HLI mice accelerated blood flow recovery and increased capillary and small artery densities. The overexpression of IGF2BP2 in HUVECs stimulated proliferation, migration, and tube formation by interacting with FGF2 mRNA to increase its stability. This interaction resulted in increased levels of FGF2 protein and secretion, ultimately promoting angiogenesis. ConclusionsIGF2BP2 contributes to blood flow restoration post-ischemia in vivo and promotes angiogenesis in HUVECs by enhancing FGF2 mRNA stability and FGF2 protein expression and secretion. These findings underscore IGF2BP2's therapeutic potential in ischemic conditions, such as PAD.

Social deficits mirror delayed cerebrovascular dysfunction after traumatic brain injury

Traumatic brain injury (TBI) survivors face debilitating long-term psychosocial consequences, including social isolation and depression. TBI modifies neurovascular physiology and behavior but the chronic physiological implications of altered brain perfusion on social interactions are unknown. Adult C57/BL6 male mice received a moderate cortical TBI, and social behaviors were assessed at baseline, 3-, 7-, 14-, 30-, and 60-days post injury (dpi). Magnetic resonance imaging (MRI, 9.4T) using dynamic susceptibility contrast perfusion weighted MRI were acquired. At 60dpi mice underwent histological angioarchitectural mapping. Analysis utilized standardized protocols followed by cross-correlation metrics. Social behavior deficits at 60dpi emerged as reduced interactions with a familiar cage-mate (partner) that mirrored significant reductions in cerebral blood flow (CBF) at 60dpi. CBF perturbations were dynamic temporally and across brain regions including regions known to regulate social behavior such as hippocampus, hypothalamus, and rhinal cortex. Social isolation in TBI-mice emerged with a significant decline in preference to spend time with a cage mate. Cortical vascular density was also reduced corroborating the decline in brain perfusion and social interactions. Thus, the late emergence of social interaction deficits mirrored the reduced vascular density and CBF in regions known to be involved in social behaviors. Vascular morphology and function improved prior to the late decrements in social function and our correlations strongly implicate a linkage between vascular density, cerebral perfusion, and social interactions. Our study provides a clinically relevant timeline of alterations in social deficits alongside functional vascular recovery that can guide future therapeutics.

New studies with stable gastric pentadecapeptide protecting gastrointestinal tract. significance of counteraction of vascular and multiorgan failure of occlusion/occlusion-like syndrome in cytoprotection/organoprotection.

Since the early 1990s, when Robert's and Szabo's cytoprotection concept had already been more than one decade old, but still not implemented in therapy, we suggest the stable gastric pentadecapeptide BPC 157 as the most relevant mediator of the cytoprotection concept. Consequently, it can translate stomach and gastrointestinal mucosal maintenance, epithelium, and endothelium cell protection to the therapy of other tissue healing (organoprotection), easily applicable, as native and stable in human gastric juice for more than 24h. These overwhelm current clinical evidence (i.e., ulcerative colitis, phase II, no side effects, and no lethal dose (LD1) in toxicology studies), as BPC 157 therapy effectively combined various tissue healing and lesions counteraction. BPC 157 cytoprotection relevance and vascular recovery, activation of collateral pathways, membrane stabilizer, eye therapy, wound healing capability, brain-gut and gut-brain functioning, tumor cachexia counteraction, muscle, tendon, ligament, and bone disturbances counteraction, and the heart disturbances, myocardial infarction, heart failure, pulmonary hypertension, arrhythmias, and thrombosis counteraction appeared in the recent reviews. Here, as concept resolution, we review the counteraction of advanced Virchow triad circumstances by activation of the collateral rescuing pathways, depending on injury, activated azygos vein direct blood flow delivery, to counteract occlusion/occlusion-like syndromes starting with the context of alcohol-stomach lesions. Counteraction of major vessel failure (congested inferior caval vein and superior mesenteric vein, collapsed azygos vein, collapsed abdominal aorta) includes counteraction of the brain (intracerebral and intraventricular hemorrhage), heart (congestion, severe arrhythmias), lung (hemorrhage), and congestion and lesions in the liver, kidney, and gastrointestinal tract, intracranial (superior sagittal sinus), portal and caval hypertension, aortal hypotension, and thrombosis, peripherally and centrally.

Injectable alginate-based zwitterionic hydrogels promoting endometrial repair and restoring fertility

The development of novel therapeutic approaches to facilitate endometrial repair and regeneration while preventing adhesion recurrence is a crucial research objective aimed at enhancing clinical outcomes for women with intrauterine adhesions (IUA). In this study, we introduced an injectable Alg-GMA/PTSB zwitterionic hydrogel, characterized by excellent biocompatibility, anti-protein adsorption properties, and biodegradability. In a rat model, the hydrogel significantly promoted the regeneration and angiogenesis of damaged endometrial tissue, leading to improved recovery of epithelial cells, glands, proliferation, and vascularization. Furthermore, it exhibited the ability to suppress cellular apoptosis and collagen deposition, thereby mitigating fibrosis. Additionally, the hydrogel restored the expression of estrogen/progesterone receptors and endometrial receptivity markers, contributing to enhanced embryo implantation and fertility. These findings underscore the potential of the hydrogel as a promising therapeutic strategy for addressing endometrial injury, reducing fibrosis, restoring fertility, and ultimately improving outcomes for women with IUA.

Pulmonary perfusion defects or residual vascular obstruction and persistent symptoms after pulmonary embolism: a systematic review and meta-analysis.

Up to 50% of pulmonary embolism (PE) patients have perfusion defects or residual vascular obstruction during follow-up despite adequate anticoagulant treatment, and a similar percentage experience chronic functional limitations and/or dyspnoea post-PE. We aimed to evaluate the association between pulmonary perfusion defects or residual vascular obstruction and functional recovery after PE. We performed a systematic review and meta-analysis including studies assessing both the presence of perfusion defects or residual vascular obstruction and functional recovery (i.e. persistent symptoms, quality of life, exercise endurance). An odds ratio was pooled for perfusion defects or residual vascular obstruction and persistent symptoms using a random-effect model. 12 studies were included totalling 1888 PE patients; at a median of 6 months after PE (range 2-72 months), 34% had perfusion defects or residual vascular obstruction and 37% reported persistent symptoms. Among patients with perfusion defects or residual vascular obstruction, 48% (95% CI 37-60%, I2=82%) remained symptomatic during follow-up, compared to 34% (95% CI 20-51%, I2=96%) of patients without such defects. Presence of perfusion defects or residual vascular obstruction was associated with persistent symptoms (OR 2.15, 95% CI 1.66-2.78; I2=0%, τ=0). Notably, there was no association between these defects and quality of life or cardiopulmonary exercise test parameters. While the odds of having persistent symptoms was higher in patients with perfusion defects or residual vascular obstruction after acute PE, a significant proportion of these patients reported no limitations. A possible causality between perfusion defects or residual vascular obstruction and residual functional limitation therefore remains to be proven.

Abstract 2030: Endothelial Deletion Of Bag3 Does Not Impair Ischemic Limb Recovery In A Murine Model Of Peripheral Artery Disease

Background: Peripheral artery disease (PAD) is a highly prevalent vascular occlusive disease which mostly affects the lower limb. Emerging studies proved the critical functions of endothelial cells in arteriogenesis and ischemic limb blood flow recovery. However, very few targets with endothelial cell exclusivity have been identified. Here, we explored the role of endothelial BCL-2 associated athanogene 3 (Bag3) in ischemic limb recovery. Hypothesis: We hypothesized that the loss of endothelial specific BAG3 would attenuate blood flow and muscle recovery following HLI. Methods: Hind limb ischemia (HLI) was induced in Bag3 Cdh5(PAC)-CreERT2 male and female mice after tamoxifen (2mg/day x 5 days) or vehicle treatment ( n ≥12/group). Limb blood flow was measured by laser Doppler perfusion imaging (LDPI) and isometric muscle force production, vascular density and muscle morphology were assessed after HLI. Results: LDPI analysis revealed no differences in the blood flow between groups at HLI d7 ( n=9 ; day 7, 21.86% ischemic/non-ischemic ± 3.80% vs 18.05% ± 1.96% SEM; p=0.05). There was no deficit in isometric force recovery of the EDL ( n ≥12; 57.76 ± 15.92 vs 83.05 ± 27.12 SEM; p =0.05) in KO animals at HLI d7. Similar rates of CD31+ vessel disorganization was observed in both groups at HLI d7, ( n =7; 4626.0 um 2 CD31+ area ± 869 vs 4870.9 ± 1056 SEM) consistent with recovering ischemic tissue. There were also no differences in blood flow recovery assessed by LDPI at HLI d28 ( n =7; 50.74% ischemic/non-ischemic ± 7.4% vs 59.17 ± 8.21; n=9). Conclusions: Endothelial cell specific Bag3 knockout did not impair vascular morphology or perfusion recovery at baseline or following HLI in a murine model of peripheral artery disease. No differences in muscle morphology or contractile function at baseline or after HLI at either timepoint were observed. In summary, we reveal an unexpectedly minor role of endothelial cell BAG3 in tissue recovery following ischemic injury.

Low-Dose Aspirin for Optimization of Postpartum Vascular Recovery Following Severe Preeclampsia: A Pilot Study

Low-Dose Aspirin for Optimization of Postpartum Vascular Recovery Following Severe Preeclampsia: A Pilot Study

Complex Interplay of Metabolic Pathways in Grafting of Ziziphus Species: Transcriptomic Insights into Regulatory Networks of Carbohydrates and Secondary Metabolite Biosynthesis

Grafting serves as a pervasive methodology in the propagation of jujube plants, yet the nuanced molecular mechanisms that dictate rootstock-scion interactions remain inadequately understood. We examined the transcriptomic landscapes of jujube heterograft combinations. Contrary to self-grafting conditions, early-stage heterografting yielded no discernible advantageous effects on scion biomass accretion. Interestingly, the rootstock’s biomass was significantly impacted by the scion, varying by species. The differentially expressed genes (DEGs) across graft combinations were mainly enriched for the vegetative growth of rootstocks, secondary metabolism, and resistance improvement of scions. Weighted gene co-expression network analysis (WGCNA) identified 27 hub genes which were negatively correlated with plant growth and biomass enlargement, serving as negative regulators, while the genes, L484_001734, ATHB-15, and BPC1, were involved in positive regulation. With biomass measurements, the transcriptomic data supported that an incomplete vascular recovery during early grafting led to nutrient accumulation at the graft junction, temporarily limiting plant growth while providing development resources for callus. In summary, our work has demonstrated that the intricate biological connections between the rootstock and scion guarantee the effective jujube grafting process by elucidating the molecular processes involved in the process.

Macrophages coordinate immune response to laser-induced injury via extracellular traps.

Retinal degeneration results from disruptions in retinal homeostasis due to injury, disease, or aging and triggers peripheral leukocyte infiltration. Effective immune responses rely on coordinated actions of resident microglia and recruited macrophages, critical for tissue remodeling and repair. However, these phagocytes also contribute to chronic inflammation in degenerated retinas, yet the precise coordination of immune response to retinal damage remains elusive. Recent investigations have demonstrated that phagocytic cells can produce extracellular traps (ETs), which are a source of self-antigens that alter the immune response, which can potentially lead to tissue injury. Innovations in experimental systems facilitate real-time exploration of immune cell interactions and dynamic responses. We integrated in vivo imaging with ultrastructural analysis, transcriptomics, pharmacological treatments, and knockout mice to elucidate the role of phagocytes and their modulation of the local inflammatory response through extracellular traps (ETs). Deciphering these mechanisms is essential for developing novel and enhanced immunotherapeutic approaches that can redirect a specific maladaptive immune response towards favorable wound healing in the retina. Our findings underscore the pivotal role of innate immune cells, especially macrophages/monocytes, in regulating retinal repair and inflammation. The absence of neutrophil and macrophage infiltration aids parenchymal integrity restoration, while their depletion, particularly macrophages/monocytes, impedes vascular recovery. We demonstrate that macrophages/monocytes, when recruited in the retina, release chromatin and granular proteins, forming ETs. Furthermore, the pharmacological inhibition of ETosis support retinal and vascular repair, surpassing the effects of blocking innate immune cell recruitment. Simultaneously, the absence of ETosis reshapes the inflammatory response, causing neutrophils, helper, and cytotoxic T-cells to be restricted primarily in the superficial capillary plexus instead of reaching the damaged photoreceptor layer. Our data offer novel insights into innate immunity's role in responding to retinal damage and potentially help developing innovative immunotherapeutic approaches that can shift the immune response from maladaptive to beneficial for retinal regeneration.

5-HT1F receptor agonism induces mitochondrial biogenesis and increases cellular function in brain microvascular endothelial cells.

Vascular and mitochondrial dysfunction are well-established consequences of multiple central nervous system (CNS) disorders, including neurodegenerative diseases and traumatic injuries. We previously reported that 5-hydroxytryptamine 1F receptor (5-HT1FR) agonism induces mitochondrial biogenesis (MB) in multiple organ systems, including the CNS. Lasmiditan is a selective 5-HT1FR agonist that is FDA-approved for the treatment of migraines. We have recently shown that lasmiditan treatment induces MB, promotes vascular recovery and improves locomotor function in a mouse model of spinal cord injury (SCI). To investigate the mechanism of this effect, primary cerebral microvascular endothelial cells from C57bl/6 mice (mBMEC) were used. Lasmiditan treatment increased the maximal oxygen consumption rate, mitochondrial proteins and mitochondrial density in mBMEC, indicative of MB induction. Lasmiditan also enhanced endothelial cell migration and tube formation, key components of angiogenesis. Trans-endothelial electrical resistance (TEER) and tight junction protein expression, including claudin-5, were also increased with lasmiditan, suggesting improved barrier function. Finally, lasmiditan treatment decreased phosphorylated VE-Cadherin and induced activation of the Akt-FoxO1 pathway, which decreases FoxO1-mediated inhibition of claudin-5 transcription. These data demonstrate that lasmiditan induces MB and enhances endothelial cell function, likely via the VE-Cadherin-Akt-FoxO1-claudin-5 signaling axis. Given the importance of mitochondrial and vascular dysfunction in neuropathologies, 5-HT1FR agonism may have broad therapeutic potential to address multiple facets of disease progression by promoting MB and vascular recovery.

Poly(ethylenimine)-Cyclodextrin-Based Cationic Polymer Mediated HIF-1α Gene Delivery for Hindlimb Ischemia Treatment.

Hindlimb ischemia is a common disease worldwide featured by the sudden decrease in limb perfusion, which usually causes a potential threat to limb viability and even amputation or death. Revascularization has been defined as the gold-standard therapy for hindlimb ischemia. Considering that vascular injury recovery requires cellular adaptation to the hypoxia, hypoxia-inducible factor 1 α (HIF-1α) is a potential gene for tissue restoration and angiogenesis. In this manuscript, effective gene delivery vector PEI-β-CD (PC) was reported for the first application in the hindlimb ischemia treatment to deliver HIF-1α plasmid in vitro and in vivo. Our in vitro finding demonstrated that PC/HIF-1α-pDNA could be successfully entered into the cells and mediated efficient gene transfection with good biocompatibility. More importantly, under hypoxic conditions, PC/HIF-1α-pDNA could up-regulate the HUEVC cell viability. In addition, the mRNA levels of VEGF, Ang-1, and PDGF were upregulated, and transcriptome results also demonstrated that the cell-related function of response to hypoxia was enhanced. The therapeutic effect of PC/HIF-1α-pDNA was further estimated in a murine acute hindlimb ischemia model, which demonstrated that intramuscular injection of PC/HIF-1α-pDNA resulted in significantly increased blood perfusion and alleviation in tissue damage, such as tissue fibrosis and inflammation. The results provide a rationale that HIF-1α-mediated gene therapy might be a practical strategy for the treatment of limb ischemia.

Translational Relevance of Advanced Age and Atherosclerosis in Preclinical Trials of Biotherapies for Peripheral Artery Disease.

Approximately 6% of adults worldwide suffer from peripheral artery disease (PAD), primarily caused by atherosclerosis of lower limb arteries. Despite optimal medical care and revascularization, many PAD patients remain symptomatic and progress to critical limb ischemia (CLI) and risk major amputation. Delivery of pro-angiogenic factors as proteins or DNA, stem, or progenitor cells confers vascular regeneration and functional recovery in animal models of CLI, but the effects are not well replicated in patients and no pro-angiogenic biopharmacological procedures are approved in the US, EU, or China. The reasons are unclear, but animal models that do not represent clinical PAD/CLI are implicated. Consequently, it is unclear whether the obstacles to clinical success lie in the toxic biochemical milieu of human CLI, or in procedures that were optimized on inappropriate models. The question is significant because the former case requires abandonment of current strategies, while the latter encourages continued optimization. These issues are discussed in the context of relevant preclinical and clinical data, and it is concluded that preclinical mouse models that include age and atherosclerosis as the only comorbidities that are consistently present and active in clinical trial patients are necessary to predict clinical success. Of the reviewed materials, no biopharmacological procedure that failed in clinical trials had been tested in animal models that included advanced age and atherosclerosis relevant to PAD/CLI.

Thrombopoietin mimetic therapy alleviates radiation-induced bone marrow vascular injury in a bone marrow transplant mouse model.

There is a need for therapies that can mitigate bone marrow dysfunction and organ toxicity that occur following myeloablative injury and reduced intensity conditioning regimens used in patients undergoing bone marrow transplantation (BMT). The pathogenesis of adverse effects from BMT conditioning has been linked to injury to the vascular endothelium, bone marrow (BM), and other organs. To evaluate the impact of the thrombopoietin mimetic drug JNJ-26366821 (TPOm) on BM vascular recovery in mice undergoing myeloablative radiation conditioning followed by BMT. TPOm (doses: 0 µg, 300 µg, 1000 µg per Kg body weight) was administered on Days 0 and 7 after BMT, in mice receiving a total body irradiation (TBI) conditioning regimen (5.5 Gy x 2) before congenic BMT. BM donner cell engraftment was analyzed using flow cytometry on Days 7, 14, and 30 post-BMT. The morphological and biophysical properties of the BM vasculature were evaluated by intravital multiphoton microscopy (MPM) and immunofluorescence confocal imaging. Herein, morphological properties involve microvascular density (MVD), vessel diameter, and vascular area, while biophysical properties include transfer rate (Ktrans) of contrast within the BM vascular niche, as well as the fractional volume (vec ) of extracellular extravascular tissue (EES). No significant difference in donor chimerism was observed at days 7, 14, and 30 post-BMT, between TPOm and PBS-treated mice. TPOm intervention improved BM vasculature regeneration in transplanted mice. The MVD, Ktrans, and BM vasculature as well as vascular endothelial growth factor receptor-2 (VEGFR2) in the BM, showed a dose dependent improvement in mice treated with TPOm. On day 14 post-BMT, the group receiving 1000 µg/Kg TPOm showed significant shifts (p-value < 0.05) in MVD, Ktrans, and VEGFR2 expression from their corresponding control types (TPOm dose 0 µg) towards levels comparable to healthy controls. TPOm intervention augments BM vascular structure and function, which may be important for hematopoietic recovery and bone marrow function in radiation conditioned hematopoietic stem cell transplant patients, in addition to enhancing platelet recovery.

Exercise and Ischemia-Activated Pathways in Limb Muscle Angiogenesis and Vascular Regeneration.

Exercise has a profound effect on cardiovascular disease, particularly through vascular remodeling and regeneration. Peripheral artery disease (PAD) is one such cardiovascular condition that benefits from regular exercise or rehabilitative physical therapy in terms of slowing the progression of disease and delaying amputations. Various rodent pre-clinical studies using models of PAD and exercise have shed light on molecular pathways of vascular regeneration. Here, I review key exercise-activated signaling pathways (nuclear receptors, kinases, and hypoxia inducible factors) in the skeletal muscle that drive paracrine regenerative angiogenesis. The rationale for highlighting the skeletal muscle is that it is the largest organ recruited during exercise. During exercise, skeletal muscle releases several myokines, including angiogenic factors and cytokines that drive tissue vascular regeneration via activation of endothelial cells, as well as by recruiting immune and endothelial progenitor cells. Some of these core exercise-activated pathways can be extrapolated to vascular regeneration in other organs. I also highlight future areas of exercise research (including metabolomics, single cell transcriptomics, and extracellular vesicle biology) to advance our understanding of how exercise induces vascular regeneration at the molecular level, and propose the idea of "exercise-mimicking" therapeutics for vascular recovery.

Inhibition of UTX/KDM6A improves recovery of spinal cord injury by attenuating BSCB permeability and macrophage infiltration through the MLCK/p-MLC pathway

Spinal cord injury (SCI) can prompt an immediate disruption to the blood–spinal cord barrier (BSCB). Restoring the integrity of this barrier is vital for the recovery of neurological function post-SCI. The UTX protein, a histone demethylase, has been shown in previous research to promote vascular regeneration and neurological recovery in mice with SCI. However, it is unclear whether UTX knockout could facilitate the recovery of the BSCB by reducing its permeability. In this study, we systematically studied BSCB disruption and permeability at different time points after SCI and found that conditional UTX deletion in endothelial cells (ECs) can reduce BSCB permeability, decrease inflammatory cell infiltration and ROS production, and improve neurological function recovery after SCI. Subsequently, we used RNA sequencing and ChIP-qPCR to confirm that conditional UTX knockout in ECs can down-regulate expression of myosin light chain kinase (MLCK), which specifically mediates myosin light chain (MLC) phosphorylation and is involved in actin contraction, cell retraction, and tight junctions (TJs) protein integrity. Moreover, we found that MLCK overexpression can increase the ratio of p-MLC/MLC, further break TJs, and exacerbate BSCB deterioration. Overall, our findings indicate that UTX knockout could inhibit the MLCK/p-MLC pathway, resulting in decreased BSCB permeability, and ultimately promoting neurological recovery in mice. These results suggest that UTX is a promising new target for treating SCI.Graphical