Pro-angiogenic Vascular Endothelial Growth Factor Research Articles

Translation of mechanistic advances in preeclampsia to the clinic: Long and winding road.

As one of the leading causes of premature birth and maternal and infant mortality worldwide, preeclampsia remains a major unmet public health challenge. Preeclampsia and related hypertensive disorders of pregnancy are estimated to cause >75 000 maternal and 500 000 infant deaths globally each year. Because of rising rates of risk factors such as obesity, invitro fertilization and advanced maternal age, the incidence of preeclampsia is going up with rates ranging from 5% to 10% of all pregnancies worldwide. A major discovery in the field was the realization that the clinical phenotypes related to preeclampsia, such as hypertension, proteinuria, and other adverse maternal/fetal events, are due to excess circulating soluble fms-like tyrosine kinase-1 (sFlt-1, also referred to as sVEGFR-1). sFlt-1 is an endogenous anti-angiogenic protein that is made by the placenta and acts by neutralizing the pro-angiogenic proteins vascular endothelial growth factor (VEGF) and placental growth factor (PlGF). During the last decade, this work has spawned a new era of molecular diagnostics for early detection of this condition. Antagonizing sFlt-1 either by reducing production or blocking its actions has shown salutary effects in animal models. Further, in early-stage human studies, the therapeutic removal of sFlt-1 from maternal circulation has shown promise in delaying disease progression and improving outcomes. Recently, the FDA approved the first molecular test for preterm preeclampsia (sFlt-1/PlGF ratio) for clinical use in the United States. Measuring serum sFlt-1/PlGF ratio in the acute hospital setting may aid short-term management, particularly regarding step-up or step-down of care, decision to transfer to settings better equipped to manage both the mother and the preterm neonate, appropriate timing of administration of steroids and magnesium sulfate, and in expectant management decisions. The test itself has the potential to save lives. Furthermore, the availability of a molecular test that correlates with adverse outcomes has set the stage for interventional clinical trials testing treatments for this disorder. In this review, we will discuss the role of circulating sFlt-1 and related factors in the pathogenesis of preeclampsia and specifically how this discovery is leading to concrete advances in the care of women with preeclampsia.

Soluble CD147 regulates endostatin via its effects on the activities of MMP-9 and secreted proteasome 20S.

During progression of rheumatoid arthritis (RA), angiogenesis provides oxygen and nutrients for the cells' increased metabolic demands and number. To turn on angiogenesis, pro-angiogenic factors must outweigh anti-angiogenic factors. We have previously shown that CD147/extracellular matrix metalloproteinase inducer (EMMPRIN) can induce the expression of the pro-angiogenic factors vascular endothelial growth factor (VEGF) and matrix metallopeptidase 9 (MMP-9) in a co-culture of the human HT1080 fibrosarcoma and U937 monocytic-like cell lines. However, whether CD147 influences anti-angiogenic factors was not known. We now show that relative to single cultures, the co-culture of these cells not only enhanced pro-angiogenic factors but also decreased the anti-angiogenic factors endostatin and thrombospondin-1 (Tsp-1), generally increasing the angiogenic potential as measured by a wound assay. Using anti-CD147 antibody, CD147 small interfering RNA (siRNA), and recombinant CD147, we demonstrate that CD147 hormetically regulates the generation of endostatin but has no effect on Tsp-1. Since endostatin is cleaved from collagen XVIII (Col18A), we applied different protease inhibitors and established that MMP-9 and proteasome 20S, but not cathepsins, are responsible for endostatin generation. MMP-9 and proteasome 20S collaborate to synergistically enhance endostatin generation, and in a non-cellular system, CD147 enhanced MMP-9 activity and hormetically regulated proteasome 20S activity. Serum samples obtained from RA patients and healthy controls mostly corroborated these findings, indicating clinical relevance. Cumulatively, these findings suggest that secreted CD147 mediates a possibly allosteric effect on MMP-9 and proteasome 20S activities and can serve as a switch that turns angiogenesis on or off, depending on its ambient concentrations in the microenvironment.

β-Caryophyllene Inhibits Endothelial Tube Formation by Modulating the Secretome of Hypoxic Lung Cancer Cells-Possible Role of VEGF Downregulation.

β-Caryophyllene (BCP), a bicyclic sesquiterpene that is a component of the essential oils of various spice and food plants, has been described as a selective CB2 cannabinoid receptor agonist. In the present study, the effect of BCP on angiogenesis was investigated. It was found that conditioned media (CM) from BCP-treated hypoxic A549 lung cancer cells exhibited a concentration-dependent inhibitory effect on human umbilical vein endothelial cell (HUVEC) tube formation induced by CM from vehicle-treated hypoxic A549 cells. There was an associated concentration-dependent decrease in the proangiogenic factor vascular endothelial growth factor (VEGF) in the CM, with both BCP inhibitory effects (tube formation, VEGF secretion) being CB2 receptor-dependent. A reduction of the transcription factor hypoxia-inducible factor 1α (HIF-1α) was furthermore detected. The antiangiogenic and VEGF-lowering properties of BCP were confirmed when CM from another lung cancer cell line, H358, were tested. When directly exposed to HUVECs, BCP showed no significant effect on tube formation, but at 10 µM, impaired VEGF receptor 2 (VEGFR2) phosphorylation triggered by recombinant VEGF in a CB2 receptor-independent manner. In summary, BCP has a dual antiangiogenic effect on HUVECs, manifested in the inhibition of tube formation through modulation of the tumor cell secretome and additionally in the inhibition of VEGF-induced VEGFR2 activation. Because the CB2 agonist has no psychoactive properties, BCP should continue to be evaluated preclinically for further antitumor effects.

Knockdown of lncRNA PVT1 protects human trabecular meshwork cells against H2O2-induced injury via the regulation of the miR-29a-3p/VEGF/MMP-2 axis

PurposeHuman trabecular meshwork cell (HTMC) dysfunction results in imbalanced aqueous humor inflow and outflow, leading to an increase in intraocular pressure (IOP). Uncontrolled high IOP can promote the occurrence of glaucoma, an irreversible optic neuropathy. Here, we explored whether the long non-coding RNA plasmacytoma variant translocation 1 (lncRNA PVT1)/microRNA-29a-3p (miR-29a-3p) axis could ameliorate HTMC dysfunction under oxidative stress by modulating the expression of the proangiogenic factor vascular endothelial growth factor (VEGFA) and the profibrotic factor metalloproteinase-2 (MMP-2). MethodsHTMCs were cultured under H2O2-induced oxidative stress for 48 h. The expression of lncRNA PVT1, miR-29a-3p, VEGFA, MMP-2, intracellular adhesion molecule-1 (ICAM-1), and alpha-smooth muscle actin (α-SMA) was detected by reverse transcription quantitative real-time polymerase chain reaction, western blotting, and immunofluorescence. Interference experiments were conducted via the transfection of HTMCs with small interfering RNA (siRNA) targeting lncRNA PVT1 or miR-29a-3p mimics. A luciferase reporter assay was undertaken to identify the presence of a miR-29a-3p binding site in lncRNA PVT1. Flow cytometry and Transwell and Cell Counting Kit-8 assays were employed to evaluate HTMC functions under oxidative stress with different treatments. ResultsIn HTMCs, the expression of lncRNA PVT1 was induced by H2O2 treatment, whereas that of miR-29a-3p was inhibited. The levels of angiogenic factors (VEGFA, ICAM-1) and fibrosis-associated mediators (MMP-2, α-SMA) were upregulated in HTMCs under oxidative stress. The siRNA-mediated suppression of lncRNA PVT1 or the upregulation of miR-29a-3p significantly suppressed the expression of VEGFA, MMP-2, ICAM-1, and α-SMA. A luciferase reporter assay confirmed that lncRNA PVT1 directly targeted miR-29a-3p and acted as a miR-29a-3p sponge. The knockdown of lncRNA PVT1 restored the level of miR-29a-3p in H2O2-treated HTMCs, thereby inhibiting VEGFA and MMP-2, its target mRNAs. HTMC dysfunction, including increased apoptosis and decreased cell mobility and viability, could be effectively ameliorated by lncRNA PVT1 downregulation or miR-29a-3p overexpression under oxidative stress. ConclusionLncRNA PVT1 has potential as a therapeutic target for inhibiting VEGFA and MMP-2, thus protecting HTMCs, suppressing the progression of fibrosis, and, consequently, improving the outcome of glaucoma filtration surgery.

Reduced Brain Cortex Angiogenesis in the Offspring of the Preeclampsia-Like Syndrome.

Children from pregnancies affected by preeclampsia have an increased risk of cognitive and behavioral alterations via unknown pathophysiology. We tested the hypothesis that preeclampsia generated reduced brain cortex angiogenesis in the offspring. The preeclampsia-like syndrome (PELS) mouse model was generated by administering the nitric oxide inhibitor NG-nitroarginine methyl ester hydrochloride. Confirmatory experiments were done using 2 additional PELS models. While in vitro analysis used mice and human brain endothelial cells exposed to serum of postnatal day 5 pups or umbilical plasma from preeclamptic pregnancies, respectively. We report significant reduction in the area occupied by blood vessels in the motor and somatosensory brain cortex of offspring (postnatal day 5) from PELS compared with uncomplicated control offspring. These data were confirmed using 2 additional PELS models. Furthermore, circulating levels of critical proangiogenic factors, VEGF (vascular endothelial growth factor), and PlGF (placental growth factor) were lower in postnatal day 5 PELS. Also we found lower VEGF receptor 2 (KDR [kinase insert domain-containing receptor]) levels in mice and human endothelial cells exposed to the serum of postnatal day 5 PELS or fetal plasma of preeclamptic pregnancies, respectively. These changes were associated with lower in vitro angiogenic capacity, diminished cell migration, larger F-actin filaments, lower number of filopodia, and lower protein levels of F-actin polymerization regulators in brain endothelial cells exposed to serum or fetal plasma of offspring from preeclampsia. Offspring from preeclampsia exhibited diminished brain cortex angiogenesis, associated with lower circulating VEGF/PlGF/KDR protein levels, impaired brain endothelial migration, and dysfunctional assembly of F-actin filaments. These alterations may predispose to structural and functional alterations in long-term brain development.

Hydrolyzed Collagen Powder Dressing Improves Wound Inflammation, Perfusion, and Breaking Strength of Repaired Tissue.

Objective: Hydrolyzed collagen-based matrices are widely used as wound care dressings. Information on the mechanism of action of such dressings is scanty. The objective of this study was to test the effect of a specific hydrolyzed collagen powder (HCP), which is extensively used for wound care management in the United States. Approach: The effects of HCP on resolution of wound inflammation, perfusion, closure, and breaking strength of the repaired skin were studied in an experimental murine model. Results: In early (day 7) inflammatory phase of wound macrophages, HCP treatment boosted phagocytosis and efferocytosis of wound-site macrophages. In these cells, inducible reactive oxygen species were also higher on day (d) 7. HCP treatment potentiated the expression of anti-inflammatory interleukin (IL)-10 cytokine and proangiogenic vascular endothelial growth factor (VEGF) production. Excisional wounds dressed with HCP showed complete closure on day 21, while the control wounds remained open. HCP treatment also demonstrated improved quality of wound healing as marked by the improved breaking strength of the closed wound tissue/repaired skin. Innovation: These data represent first evidence on the mechanism of action of clinically used HCP. Conclusion: HCP dressing favorably influenced both wound inflammation and vascularization. Improved breaking strength of HCP-treated repaired skin lays the rationale for future studies testing the hypothesis that HCP-treated closed wounds would show fewer recurrences.

Canagliflozin improves coronary microvascular vasodilation and increases absolute blood flow to the myocardium independent of angiogenesis

ObjectivesSodium-glucose cotransporter-2 inhibitor, canagliflozin, improves myocardial perfusion to ischemic territory without accompanying changes in vascular density. We aimed to (1) characterize effects on angiogenic pathways, (2) use multiomics to identify gene expression and metabolite profiles relevant to regulation of myocardial blood flow, and (3) investigate drug effect on coronary microvascular reactivity. MethodsA nondiabetic swine model of chronic myocardial ischemia and nondiabetic rat model were used to study functional and molecular effects of canagliflozin on myocardium and in vitro microvascular reactivity. ResultsCanagliflozin resulted in increased coronary microvascular vasodilation and decreased vasoconstriction (P < .05) without changes in microvascular density (P > .3). Expression of the angiogenic modulator, endostatin, increased (P = .008), along with its precursor, collagen 18 (P < .001), and factors that increase its production, including cathepsin L (P = .004). Endostatin and collagen 18 levels trended toward an inverse correlation with blood flow to ischemic territory at rest. Proangiogenic fibroblast growth factor receptor was increased (P = .03) and matrix metalloproteinase-9 was decreased (P < .001) with canagliflozin treatment. Proangiogenic vascular endothelial growth factor A (P = .13), Tie-2 (P = .10), and Ras (P = .18) were not significantly altered. Gene expression related to the cardiac renin-angiotensin system was significantly decreased. ConclusionsIn chronic myocardial ischemia, canagliflozin increased absolute blood flow to the myocardium without robustly increasing vascular density or proangiogenic signaling. Canagliflozin resulted in altered coronary microvascular reactivity to favor vasodilation, likely through direct effect on vascular smooth muscle. Downregulation of cardiac renin-angiotensin system demonstrated local regulation of perfusion. Video Abstract [Display omitted]

Novel mediators regulating angiogenesis in diabetic foot ulcer healing.

A non-healing diabetic foot ulcer (DFU) is a debilitating clinical problem amounting to socioeconomic and psychosocial burdens. DFUs increase morbidity due to prolonged treatment and mortality in the case of non-treatable ulcers resulting in gangrene and septicemia. The overall amputation rate of the lower extremity with DFU ranges from 3.34% to 42.83%. Wound debridement, antibiotics, applying growth factors, negative pressure wound therapy, hyperbaric oxygen therapy, topical oxygen, and skin grafts are common therapies for DFU. However, recurrence and nonhealing ulcers are still major issues. Chronicity of inflammation, hypoxic environment, poor angiogenesis, and decreased formation of the extracellular matrix (ECM) are common impediments leading to nonhealing patterns of DFUs. Angiogenesis is crucial for wound healing since proper vessel formation facilitates nutrients, oxygen, and immune cells to the ulcer tissue to help in clearing out debris and facilitate healing. However, poor angiogenesis due to decreased expression of angiogenic mediators and matrix formation results in nonhealing and ultimately amputation. Multiple proangiogenic mediators and vascular endothelial growth factor (VEGF) therapy exist to enhance angiogenesis, but the results are not satisfactory. Thus, there is a need to investigate novel pro-angiogenic mediators that can either alone or in combination enhance the angiogenesis and healing of DFUs. In this article, we critically reviewed the existing pro-angiogenic mediators followed by potentially novel factors that might play a regulatory role in promoting angiogenesis and wound healing in DFUs.

Xanthine derivative KMUP-1 ameliorates retinopathy

Retinal neovascularization (RNV) and cell apoptosis observed in retinopathy are the most common cause of vision loss worldwide. Increasing vascular endothelial growth factor (VEGF), which was driven by hypoxia or inflammation, would result in RNV. This study investigated the anti-inflammatory and anti-apoptotic xanthine-based derivative KMUP-1 on hypoxia-induced conditions in vitro and in vivo. In the oxygen-induced retinopathy animal model, KMUP-1 mitigated vaso-obliteration and neovascularization. In the cell model of hypoxic endothelium cultured at 1% O2, KMUP-1 inhibited endothelial migration and tube formation and had no cytotoxic effect on cell growth. Upregulation of pro-angiogenic factors, HIF-1α and VEGF, and pro-inflammatory cytokines, IL-1β and TNF-α, expression in the retinal-derived endothelial cells, RF/6 A cells, upon hypoxia stimulation, was suppressed by KMUP-1 treatment. RF/6 A cells treated with KMUP-1 showed a reduction of PI3K/Akt, ERK, and RhoA/ROCKs signaling pathways and induction of protective pathways such as eNOS and soluble guanylyl cyclase at 1% O2. Furthermore, KMUP-1 decreased the expression of VEGF, ICAM-1, TNF-α, and IL-1β and increased the BCL-2/BAX ratio in the oxygen-induced retinopathy mouse retina samples. In conclusion, the results of this study suggest that KMUP-1 has potential therapeutic value in retinopathy due to its triple effects on anti-angiogenesis, anti-inflammation, and anti-apoptosis in hypoxic endothelium.

P-760 Effect of relaxin on human endometrial stromal cell characteristics

Abstract Study question Does relaxin (RLX) regulate decidualization and pro- and antiangiogenic factors in primary human endometrial stromal cells (hESC), primary decidual cells (pD) and hTERT-immortalized hESC (T hESC)? Summary answer RLX treatment enhances decidualization and affects the mRNA expression levels of pro- and antiangiogenic factors. What is known already Patients undergoing frozen embryo transfer in an artificial cycle (AC-FET) are at a 2-fold increased risk for preeclampsia compared to embryo transfer in a natural cycle. This may be related to the absence of the corpus luteum in an artificial FET cycle, which produces important hormones such as estrogen and progesterone in early pregnancy. These hormones are supplied during AC-FET, whereas other products of the corpus luteum, such as RLX, are not. Low maternal RLX levels were found in women who developed preeclampsia, but the direct relationship between RLX and the occurrence of preeclampsia remains to be elucidated. Study design, size, duration Primary hESC were isolated from biopsies of women without endometrial pathology, pD cells from biopsies of the maternal side of the placenta of uncomplicated pregnancies and T hESC purchased from American Type Culture Collection. Cells were decidualized with either 0.5 mM cyclic adenosine monophosphate (cAMP) or a cocktail of 10 nM estradiol, 1 µM progesterone and 0.5 mM cAMP (EPC) and additionally treated with 0, 0.3 or 1 ng/ml RLX for twelve days. Participants/materials, setting, methods RNA was isolated on day zero and day twelve from all three cell types. mRNA expression level of decidualization markers (prolactin (PRL), insulin like growth factor binding protein 1 (IGFBP1)) as well as pro- and antiangiogenic factors (vascular endothelial growth factor (VEGF); placenta like growth factor (PlGF); soluble Fms-like tyrosine kinase-1 (sFlt-1); and endoglin (ENG)) were evaluated by quantitative real time polymerase chain reaction (qRT-PCR), N = 3 biological replicates. Main results and the role of chance Decidualization treatment of hESC with cAMP caused more noticeable changes to cell morphology than treatment with EPC. While there was no rise of decidualization markers PRL (p = 0.99) and IGFBP1 (p = 0.95) in the cAMP treatment group, hESC after EPC treatment showed a significant increase in both PRL (p = 0.0003) and IGFBP1 (p = 0.0001). RLX treatment in the EPC treated hESC and pD significantly increased the mRNA expression levels of PRL and IGFBP1 (both p &amp;lt; 0.05, respectively), as well as the expression of the proangiogenic marker VEGF (P = 0.05). A comparative analysis with T hESC showed a moderate effect on VEGF and PlGF. No effect of RLX was detected for IGFBP1 and PRL mRNA expression levels. The mRNA expression level of the antiangiogenic marker ENG increased in the EPC group in both, primary hESC (P = 0.04) and T hESC (P = 0.01) after treatment with 0.3 ng/ml RLX compared to control. ENG mRNA expression level increased in a dose dependent manner in pD but not in hESC and T hESC. RLX treatment with 1ng/ml of cAMP decidualized hESC significantly enhanced mRNA expression levels of VEGF (P = 0.002) and PlGF (P = 0.02) only in hESC but not in T hESC or pD. Limitations, reasons for caution Our pilot study indicates that RLX treatment improves decidualization and affects pro- and antiangiogenic factors in three different human endometrial stromal cell models. A wider approach is needed to investigate the effects of RLX in the decidualization process and pro- and antiangiogenic factors. Wider implications of the findings Our results provide the basis for further studies elucidating the relationship between low maternal RLX levels and the occurrence of preeclampsia. This could lead to the development of improved prediction models and new treatment options in assisted reproduction that reduce the risk of preeclampsia, e.g. in AC-FET. Trial registration number Not applicable

Hypoxia-Preconditioned Bone Marrow Mesenchymal Stem Cells Improved Cerebral Collateral Circulation and Stroke Outcome in Mice.

Adequate collateral circulation can remarkably improve patient prognoses for patients experiencing ischemic stroke. Hypoxic preconditioning enhances the regenerative properties of bone marrow mesenchymal stem cells (BMSCs). Rabep2 (RAB GTPase binding effector protein 2) is a key protein in collateral remodeling. We investigated whether BMSCs and hypoxia-preconditioned BMSCs (H-BMSCs) augment collateral circulation poststroke, particularly through Rabep2 regulation. BMSCs or H-BMSCs (1×106) were delivered intranasally in ischemic mice with distal middle cerebral artery occlusion at 6 hours poststroke. Two-photon microscopic imaging and vessel painting methods were used to analyze collateral remodeling. Blood flow, vascular density, infarct volume, and gait analysis were assessed to evaluate poststroke outcomes. Expressions of proangiogenic marker VEGF (vascular endothelial growth factor) and Rabep2 were determined by Western blotting. Western blot, EdU (5-ethynyl-2'-deoxyuridine) incorporation, and tube formation assays were conducted on cultured endothelial cells treated with BMSCs. BMSCs were more effectively transplanted in the ischemic brain after hypoxic preconditioning. The ipsilateral collateral diameter was increased by BMSCs and strengthened by H-BMSCs (P<0.05). BMSCs increased peri-infarct blood flow and vascular density and reduced infarct volume, gait deficits (P<0.05), and furthermore by H-BMSCs (P<0.05). VEGF and Rabep2 protein expression was increased by BMSCs (P<0.05), which was enhanced by preconditioning (P<0.01). Additionally, BMSCs increased Rabep2 expression, proliferation, and tube formation of endothelial cells in vitro (P<0.05). H-BMSCs enhanced these effects (P<0.05), which were annulled by Rabep2 knockdown. BMSCs increased collateral circulation and improved poststroke outcomes, through the upregulation of Rabep2. These effects were enhanced by hypoxic preconditioning.

Abstract 683: Improved Myocardial Blood Flow And Arteriogenesis With Calpain Inhibition May Be Mediated By Vascular Endothelial Growth Factor And Fibroblast Growth Factor Angiogenic Pathways In A Large-animal Model Of Metabolic Syndrome And Chronic Myocardial Ischemia

Objective: Ischemic heart disease is the leading cause of death worldwide. Under pathological conditions like myocardial ischemia, endothelial calpain proteases are activated by hypoxia, leading to aberrant angiogenesis. Our group has shown calpain inhibition increases myocardial blood flow and vascular density, microvascular vasodilation, and expression of proangiogenic vascular endothelial growth factor (VEGF) and its receptors (VEGF-R1, VEGF-R2) in a porcine model of chronic myocardial ischemia and diet-induced metabolic syndrome. We aim to assess the role of downstream factors in angiogenic pathways. Methods: Yorkshire swine were fed a high cholesterol diet for four weeks, and then underwent placement of an ameroid constrictor to the left circumflex artery. After three weeks, pigs received either daily calpain inhibitor MDL28170 (0.25mg/kg, oral) for five weeks (n = 8) or no drug (n = 7), followed by tissue harvest of ischemic myocardium. Results: Treatment was associated with a significant increase in expression of proangiogenic mediators, fibroblast growth factor (FGF) receptor 1 (FGFR1, p &lt;0.001) and matrix metalloprotease-2 (MMP-2, p &lt;0.001). Cathepsins D and L have been implicated in both pro- and antiangiogenic actions. Cathepsin D was significantly increased (p = 0.004), but Cathepsin L was unchanged (p &gt;0.99). Cathepsin L proenzyme, procathepsin L, was significantly decreased (p = 0.04), while there was a strong trend toward decreased procathepsin L:cathepsin L ratio (p = 0.09). Proangiogenic Tie-2 (p = 0.28), and antiangiogenic collagen 18 (p = 0.54) and angiostatin (p = 0.24) were unchanged. Conclusions: In metabolic syndrome, calpain inhibition led to increased proangiogenic signaling in chronically ischemic myocardium, suggesting angiogenic VEGF- and FGF-mediated pathways may work in concert with improved microvascular vasodilation to explain the observed increase in vascular density and collateral-dependent coronary perfusion.

Exogenous ketosis elevates circulating erythropoietin and stimulates muscular angiogenesis during endurance training overload.

De novo capillarization is a primary muscular adaptation to endurance exercise training and is crucial to improving performance. Excess training load, however, impedes such beneficial adaptations, yet we recently demonstrated that such downregulation may be counteracted by ketone ester ingestion (KE) post-exercise. Therefore, we investigated whether KE could increase pro-angiogenic factors and thereby stimulate muscular angiogenesis during a 3-week endurance training-overload period involving 10 training sessions/week in healthy, male volunteers. Subjects received either 25g of a ketone ester (KE, n=9) or a control drink (CON, n=9) immediately after each training session and before sleep. In KE, but not in CON, the training intervention increased the number of capillary contacts and the capillary-to-fibre perimeter exchange index by 44% and 42%, respectively. Furthermore, KE also substantially increased vascular endothelial growth factor (VEGF) and endothelial nitric oxide synthase (eNOS) expression both at the protein and at the mRNA level. Serum erythropoietin concentration was concomitantly increased by 26%. Conversely, in CON the training intervention increased only the protein content of eNOS. These data indicate that intermittent exogenous ketosis during endurance overload training stimulates muscular angiogenesis. This likely resulted from a direct stimulation of muscle angiogenesis, which may be at least partly due to stimulation of erythropoietin secretion and elevated VEGF activity, and/or an inhibition of the suppressive effect of overload training on the normal angiogenic response to training. This study provides novel evidence to support the potential of exogenous ketosis to benefit endurance training-induced muscular adaptation. KEY POINTS: Increased capillarization is a primary muscular adaptation to endurance exercise training. However, excess training load may impede such response. We previously observed that intermittent exogenous ketosis by post-exercise and pre-sleep ketone ester ingestion (KE) counteracted physiological dysregulations induced by endurance overload training. Therefore, we investigated whether KE could increase pro-angiogenic factors thereby stimulating muscular angiogenesis during a 3-week endurance training overload period. We show that the overload training period in the presence, but not in the absence, of KE markedly increased muscle capillarization (+40%). This increase was accompanied by higher circulating erythropoietin concentration and stimulation of the pro-angiogenic factors vascular endothelial growth factor and endothelial nitric oxide synthase in skeletal muscle. Collectively, our data indicate that intermittent exogenous ketosis may evolve as a potent nutritional strategy to facilitate recovery from strenuous endurance exercise, thereby stimulating beneficial muscular adaptations.

Spatial control of self-organizing vascular networks with programmable aptamer-tethered growth factor photopatterning.

Given the dynamic nature of engineered vascular networks within biofabricated tissue analogues, it is instrumental to have control over the constantly evolving biochemical cues within synthetic matrices throughout tissue remodeling. Incorporation of pro-angiogenic vascular endothelial growth factor (VEGF165) specific aptamers into cell-instructive polymer networks is shown to be pivotal for spatiotemporally controlling the local bioactivity of VEGF that selectively elicit specific cell responses. To harness this effect and quantitatively unravel its spatial resolution, herein, bicomponent micropatterns consisting of VEGF165 specific aptamer-functionalized gelatin methacryloyl (GelMA) (aptamer regions) overlaid with pristine GelMA regions using visible-light photoinitiators (Ru/SPS) were fabricated via two-step photopatterning approach. For the 3D co-culture study, human umbilical vein-derived endothelial cells and mesenchymal stromal cells were used as model cell types. Bicomponent micropatterns with spatially defined spacings (300/500/800​μm) displayed high aptamer retention, aptamer-fluorescent complementary sequence (CSF) molecular recognition and VEGF sequestration localized within patterned aptamer regions. Stiffness gradient at the interface of aptamer and GelMA regions was observed with high modulus in aptamer region followed by low stiffness GelMA regions. Leveraging aptamer-tethered VEGF's dynamic affinity interactions with CS that upon hybridization facilitates triggered VEGF release, co-culture studies revealed unique characteristics of aptamer-tethered VEGF to form spatially defined luminal vascular networks covered with filopodia-like structures in vitro (spatial control) and highlights their ability to control network properties including orientation over time using CS as an external trigger (temporal control). Moreover, the comparison of single and double exposed regions within micropatterns revealed differences in cell behavior among both regions. Specifically, the localized aptamer-tethered VEGF within single exposed aptamer regions exhibited higher cellular alignment within the micropatterns till d5 of culture. Taken together, this study highlights the potential of photopatterned aptamer-tethered VEGF to spatiotemporally regulate vascular morphogenesis as a tool for controlling vascular remodeling in situ.

Acellular biomaterial modulates myocardial inflammation and promotes endogenous mechanisms of postinfarct cardiac repair.

After myocardial infarction, we previously showed that epicardial implantation of porcine small intestinal submucosal extracellular matrix (SIS-ECM) improves postinfarct cardiac function through fibroblast-mediated angiogenic and antifibrotic pathways. Herein, we characterize how SIS-ECM also coordinates a reparative cardiac inflammatory response. RNA sequencing and multiplex characterized modulation of fibroblast transcriptional and paracrine activity by SIS-ECM. Inhibitors of fibroblast growth factor 2 and toll-like receptor 9 elucidated mechanism. Mice received coronary ligation (infarction) and either SIS-ECM implantation (treatment) or sham surgery (control). Flow cytometry of SIS-ECM and the murine myocardium quantified monocytes, neutrophils, and proangiogenic subtypes. Microscopy tracked fibroblasts and immune cells, and characterized myocardial angiogenesis. SIS-ECM increased fibroblast transcription of inflammatory pathways and production of angiogenic vascular endothelial growth factor and inflammatory cytokines via fibroblast growth factor 2 and toll-like receptor 9-dependent pathways. Two-photon microscopy showed that SIS-ECM became engrafted by native fibroblasts and leukocytes, subsequently increasing release of inflammatory cytokines and angiogenic vascular endothelial growth factor. On flow cytometry, SIS-ECM implantation increased day-7 myocardial counts of neutrophils, inflammatory monocytes, and proangiogenic vascular endothelial growth factor recptor 1 subtypes. SIS-ECM has a higher proportion of proangiogenic leukocytes compared with the myocardium. Resonant confocal microscopy showed neovascularization near SIS-ECM. SIS-ECM promotes engraftment by native fibroblasts and leukocytes, and modulates fibroblast activity via fibroblast growth factor 2 and toll-like receptor 9 to potentiate a proangiogenic inflammatory response. Subsequently, the material increases myocardial counts of reparative proangiogenic leukocytes that can induce neovascularization. This reparative inflammatory response may explain previously reported functional improvements. Fibroblast growth factor 2 and toll-like receptor 9 mechanisms can be leveraged to design next-generation materials for postinfarct cardiac repair.

Irisin Modulates Inflammatory, Angiogenic, and Osteogenic Factors during Fracture Healing.

Bone fractures are a widespread clinical event due to accidental falls and trauma or bone fragility; they also occur in association with various diseases and are common with aging. In the search for new therapeutic strategies, a crucial link between irisin and bone fractures has recently emerged. To explore this issue, we subjected 8-week-old C57BL/6 male mice to tibial fracture, and then we treated them with intra-peritoneal injection of r-Irisin (100 µg/kg/weekly) or vehicle as control. At day 10 post fracture, histological analysis showed a significant reduced expression of inflammatory cytokines as tumor necrosis factor-alpha (TNFα) (p = 0.004) and macrophage inflammatory protein-alpha (MIP-1α) (p = 0.015) in the cartilaginous callus of irisin-treated mice compared to controls, supporting irisin's anti-inflammatory role. We also found increased expressions of the pro-angiogenic molecule vascular endothelial growth factor (VEGF) (p = 0.002) and the metalloproteinase MMP-13 (p = 0.0006) in the irisin-treated mice compared to the vehicle ones, suggesting a myokine involvement in angiogenesis and cartilage matrix degradation processes. Moreover, the bone morphogenetic protein (BMP2) expression was also upregulated (p = 0.002). Taken together, our findings suggest that irisin can contribute to fracture repair by reducing inflammation and promoting vessel invasion, matrix degradation, and bone formation, supporting its possible role as a novel molecule for fracture treatment.

Low-Dose Erythropoietin Amplifies Beneficial Effects of Angiotensin II Blockade on Glomerulosclerosis

Exogenous erythropoietin (EPO) is used to treat anemia in patients with chronic kidney disease (CKD). Concerns about the possible adverse effect of EPO on the progression of CKD have been raised owing to nonerythroid cell effects. We investigated the effects of low-dose EPO, independent of correcting anemia, on existing glomerulosclerosis. Adult mice underwent 5/6 nephrectomy and were randomized into the following 4 groups at week 8 after surgery: vehicle (VEH), losartan (angiotensin II type 1 receptor blocker [ARB]), darbepoetin-α (DA), or combination (DA+ARB). Four weeks later, mice were euthanized, followed by evaluation of renal structure and function. Glomerular endothelial cells and podocytes were cultured to evaluate the effects of DA on cell migration, apoptosis, and Akt signaling. ARB reduced blood pressure, albuminuria, and the level of serum creatinine and increased hematocrit compared with VEH, whereas low-dose DA only reduced the level of serum creatinine. Combination treatment showed a trend to increase hematocrit and survival compared with ARB alone. Combination treatment but not ARB alone significantly reduced the progression of glomerulosclerosis compared with VEH. Low-dose DA resulted in more preserved glomerular and peritubular capillary endothelial cells with increased p-Akt and even further endothelial cell preservation in combination with ARB. In cultured glomerular endothelial cells, angiotensin II induced more apoptosis, reduced migration, and decreased p-Flk1, a receptor for the proangiogenic vascular endothelial growth factor. DA counteracted these injuries and increased p-Akt, a key factor in angiogenesis and cell survival. DA also protected cultured podocytes against transforming growth factor β–induced apoptosis and synaptopodin loss. Low-dose EPO directly protects glomerular and peritubular endothelial cells via Akt phosphorylation. Therefore, treatment using a combination of low-dose EPO and ARB results in less progression of glomerulosclerosis in an experimental CKD model.

Is the Long‐term Impact of a Multidomain Lifestyle Intervention on Cognitive Function Mediated by Changes in Leptin and Vascular Endothelial Growth Factor Concentrations?

AbstractBackgroundThe 10‐year intensive lifestyle intervention (ILI) of the Look AHEAD study resulted in a legacy of relative deficits in cognitive function among participants who entered the clinical trial with a history of cardiovascular disease or current obesity, as compared to participants assigned to the diabetes support and education (DSE) intervention. We hypothesized that levels of two weight‐sensitive proangiogenic cytokines, leptin and vascular endothelial growth factor (VEGF), which have been previously reported to be associated with cognitive function, may have been altered by the ILI and account for this concerning finding.MethodConcentrations of leptin and VEGF were determined using stored serum collected from 1,279 participants at Look AHEAD baseline, proximal to cessation of the intervention (Epoch 1), and an average of 4 years later (Epoch 2). Masked clinic staff conducted up to four standardized assessments of cognitive function at times ranging from 8 to 18 years after baseline. A composite score was derived from tests of attention, executive function, and memory. Mixed effects models were used to assess relative differences in leptin and VEGF concentrations between intervention groups and whether these accounted for changes in cognitive composite scores, overall and within subgroups defined by baseline history of cardiovascular disease or obesity.ResultIn both intervention groups, leptin concentrations increased from baseline to Epoch 1, and further between Epochs 1 and 2 (p&lt;0.001). VEGF concentrations decreased between enrollment and Epoch 2 in both groups, and decreased substantially more between Epoch 1 and 2 in ILI than in DSE (p = 0.04). Overall, there was little evidence that leptin and VEGF concentrations were related to cognitive functioning. ILI‐DSE differences in VEGF, but not leptin, concentrations varied depending on baseline history of cardiovascular disease and obesity, but neither leptin or VEGF concentrations accounted for the relative decrements in cognitive function evident during long‐term follow‐up in participants assigned to ILI.ConclusionAmong persons with type 2 diabetes and either a history of cardiovascular disease or obesity, long‐term relative deficits in cognitive function associated with intensive lifestyle intervention are not related to differences in two weight‐sensitive proangiogenic cytokines.

Indole-3-Carbinol Inhibits the Growth of Endometriotic Lesions by Suppression of Microvascular Network Formation.

Endometriosis represents an estrogen-dependent disorder with a complex pathophysiology. Phytochemicals are promising candidates for endometriosis therapy, because they simultaneously target different cellular processes involved in the pathogenesis of endometriosis. Herein, we analyzed whether indole-3-carbinol (I3C) suppresses the development of endometriotic lesions, which were surgically induced by fixation of uterine tissue samples (diameter: 2 mm) from female BALB/c donor mice to the peritoneum of recipient animals. The mice received either I3C or vehicle (control) by peroral administration once per day. Growth, cyst formation, cell proliferation, microvascularization and protein expression of the lesions were assessed by high-resolution ultrasound imaging, caliper measurements, histology, immunohistochemistry and Western blotting. I3C inhibited the vascularization and growth of endometriotic lesions without inducing anti-angiogenic and anti-proliferative side effects on reproductive organs. This was associated with a significantly reduced number of proliferating stromal and endothelial cells and a lower expression of the pro-angiogenic signaling molecules vascular endothelial growth factor receptor-2 (VEGFR2), phosphoinositide 3-kinase (PI3K) and phosphorylated extracellular signal-regulated kinase (pERK) within I3C-treated lesions when compared to controls. These findings indicate that I3C effectively inhibits endometriotic lesion formation in mice. Thus, further studies should clarify whether I3C may be also beneficial for the prevention and therapy of the human disease.

Antineoplastic agents in chemotherapy facilitating tumor growth and angiogenesis in the interval administrations

AimsThere is emerging evidence that antineoplastic agents and the cytotoxic effects on tumor tissues attenuate the benefits of chemotherapy due to tumor microenvironment changes. Nevertheless, the actual relationship between chemotherapy and recurrent tumors in which the genotypes differ from the original tumor after chemotherapy is unclear. Materials and methodsBone marrow transplantation, flow cytometer, immune inhibition and immunofluorescence will be utilized to investigate the effect of antineoplastic agents on bone-marrow-derived cells (BMDCs) release and recruitment, and to explore the pathways and mechanisms of antineoplastic agents in promoting tumor growth. Key findingsTumor growth and angiogenesis were significantly enhanced in the mouse model after treatment with antineoplastic agents such as cyclophosphamide, 5-fluorouracil, or cisplatin, along with large increases in proangiogenic vascular endothelial growth factor receptor-2 (VEGFR2+), β3+, CD11b+Gr-1+, and VEGFR2+β3+ BMDCs in circulating blood. BMDC recruitment and VEGFR2 and β3 mRNA transcription in tumor tissues were also enhanced by antineoplastic agents. Antineoplastic-agent-treated BMDCs markedly augmented tumor and endothelial cell proliferation, and β3 mRNA transcription in endothelial cells (ECs). SignificanceThe results suggested that antineoplastic-agent treatment augmented the tumor microenvironment by mobilizing proangiogenic BMDCs, enhancing BMDC recruitment and angiogenesis, and increasing BMDC-mediated tumor and EC functions. These results led to tumor growth and angiogenesis aggravation. It is paramount to elucidate the potential mechanism by which the cellular and molecular effects triggered by the antineoplastic agents attenuate the effects of cancer therapy, and thereafter to explore possible methods for improving tumor treatment efficacy.