The essential anti-angiogenic strategies in cartilage engineering and osteoarthritic cartilage repair.

In the cartilage matrix, complex interactions occur between angiogenic and anti-angiogenic components, growth factors, and environmental stressors to maintain a proper cartilage phenotype that allows for effective load bearing and force distribution. However, as seen in both degenerative disease and tissue engineering, cartilage can lose its vascular resistance. This vascularization then leads to matrix breakdown, chondrocyte apoptosis, and ossification. Research has shown that articular cartilage inflammation leads to compromised joint function and decreased clinical potential for regeneration. Unfortunately, few articles comprehensively summarize what we have learned from previous investigations. In this review, we summarize our current understanding of the factors that stabilize chondrocytes to prevent terminal differentiation and applications of these factors to rescue the cartilage phenotype during cartilage engineering and osteoarthritis treatment. Inhibiting vascularization will allow for enhanced phenotypic stability so that we are able to develop more stable implants for cartilage repair and regeneration.

Experimental study on anti angiogenesis of recombinant mouse angiostatin gene in mice with gallbladder carcinoma.

Gallbladder cancer is one of the gastrointestinal tumors with an extremely poor prognosis. Its incidence rate is gradually increasing worldwide, and the rate of radical resection surgery is extremely low. Not sensitive to radiotherapy and chemotherapy, with a very poor prognosis. This study aimed to investigate whether the recombinant mouse angiostatin gene transfected anti-angiogenic gallbladder cancer cells can express angiostatin protein with the activity of inhibiting the growth of vascular endothelial cells and the inhibitory effect on the growth of gallbladder cancer. The recombinant mouse angiostatin gene eukaryotic expression plasmid was transfected into the gallbladder cancer cell line by applying liposome LIPOFECTAMINE 2000, and its activity was detected by vascular endothelial cell proliferation analysis. The results show that angiostatin can inhibit the growth of transplanted gallbladder cancer, and as the number of injections increases, the inhibition rate of gallbladder cancer growth also increases. At the end of the experiment, the total inhibition rate of gallbladder cancer growth reached 95% 5%, 20%, 30%, 40% gradually increase. Therefore, angiostatin has potential clinical application value in gene therapy of gallbladder cancer.

Synergistic Effect of Baculovirus-Mediated Endostatin and Angiostatin Combined with Gemcitabine in Hepatocellular Carcinoma.

Anti-angiogenic gene therapy is a promising strategy in treating cancer. Endostatin and angiostatin are widely used in tumor anti-angiogenesis therapy. Our previous studies have shown that the BDS-hEA, a baculovirus long-term expressing the fusion protein of human endostatin and angiostatin, has a favorable effect in inhibiting the growth and angiogenesis of hepatocellular carcinoma. The purpose of this study was to further investigate its synergistic antitumor efficiency in combination with low-dose chemotherapeutic gemcitabine (GEM) on the subcutaneous hepatocellular carcinoma xenograft model in nude mice. The results showed that the combined group significantly inhibited (p < 0.05 or p < 0.01 or p < 0.001) the growth of tumor weight and volume, reduced the expression of ki67 (cell proliferation marker), CD31 (angiogenic marker) and Matrix metalloproteinase 9 (MMP-9, tumor invasion and metastasis marker) and increased the apoptosis of tumor cells compared with the monotherapy and control groups, respectively. Synergistic index results showed that BDS-hEA combined with GEM had a synergistic effect in inhibiting tumor volume, proliferation, microvessel density, metastasis and promoting tumor apoptosis. Furthermore, there were no metastatic nodules and obvious pathological changes in liver tissue of the combined group, and the serum liver function indicators aspartate aminotransferase (AST), alanine aminotransferase (ALT), total bilirubin (T-BIL), alkaline phosphatase (ALP) and glutamyl transpeptidase (GGT) were significantly reduced (p < 0.05 or p < 0.01 or p < 0.001) in the BDS-hEA or GEM groups compared with the control group. Notably, the combined therapy showed lower levels of liver function indicators than the GEM group. These data support the view that the combination of BDS-hEA and GEM has a synergistic anti-tumor properties and can reduce the damage of liver to certain extent.

Assessment of selected angiogenesis markers in the serum of middle-aged male patients with plaque psoriasis.

Local angiogenesis accompanies inflammation in psoriasis-affected skin. To determine the serum concentrations of selected pro- and anti-angiogenic factors and their interrelationships in patients with plaque psoriasis. The study included 41 men diagnosed with psoriasis, aged 43.5 ± 11.7 years. The Psoriasis Area and Severity Index score was 23.4 ± 5.2 points. The control group consisted of 38 healthy, age-matched men. The levels of pro-angiogenic cytokines and angiogenesis inhibitors, including fibroblast growth factor 1 (FGF-1), vascular endothelial growth factor A (VEGF-A), endostatin, and angiostatin, were determined from the serum of patients and controls using enzyme-linked immunosorbent assays. Compared with controls, patients with psoriasis had a significantly lower concentration of FGF-1 (P = .01) but higher concentrations of endostatin (P = .04) and angiostatin (P = .02). The concentration of VEGF-A was also higher in patients with psoriasis but not significantly (P = .25). The concentration of C-reactive protein (CRP) was significantly higher among patients with psoriasis than controls (P < .0001). Among controls, CRP concentrations did not correlate significantly with the concentrations of FGF-1, VEGF-A, endostatin, or angiostatin. Among patients with psoriasis, CRP concentrations correlated moderately with the concentrations of VEGF-A (r = .35; P = .02) and angiostatin (r = .31; P = .04). The concentration of VEGF-A correlated positively with PASI (r = .05; P = .0009) and BSA values (r = .39; P = .01). Psoriasis is associated with an altered systemic balance between pro-angiogenic and anti-angiogenic factors. The increase in serum angiogenesis inhibitors may be associated with unfavorable changes in the development of coronary collateral circulation. However, the clinical significance of this has not yet been established.

Exercise training ameliorates cognitive dysfunction in amyloid beta-injected rat model: possible mechanisms of Angiostatin/VEGF signaling.

Vascular endothelial growth factor (VEGF) regulates angio/neurogenesis and also tightly links to the pathogenesis of Alzheimer's disease (AD). Although exercise has a beneficial effect on neurovascular function and cognitive function, the direct effect of exercise on VEGF-related signaling and cognitive deficit in AD is incompletely understood. Therefore, the purpose of this study was to investigate the protective effect of exercise on angiostatin/VEGF cascade and cognitive function in AD model rats. Wistar male rats were randomly divided into five groups: control (CON), injection of DMSO (Sham-CON), CON-exercise (sham-EX), intrahippocampal injection of Aß (Aß), and Aß-exercise (Aß-EX). Rats in EX groups underwent treadmill exercise for 4 weeks, then the cognitive function was measured by the Morris Water Maze (MWM) test. mRNA levels of hypoxia-induced factor-1α (HIF-1α), vascular endothelial growth factor (VEGF), vascular endothelial growth factor receptor 2 (VEGFR2), and angiostatin were determined in hippocampus by RT-PCR. We found that spatial learning and memory were impaired in Aß-injected rats, but exercise training improved it. Moreover, exercise training increased the reduced mRNA expression level of VEGF signaling, including HIF1α, VEGF, and VEGFR2 in the hippocampus from Aß-injected rats. Also, the mRNA expression level of angiostatin was elevated in the hippocampus from Aß-injected rats, and exercise training abrogated its expression. Our findings suggest that exercise training improves cognitive function in Aß-injected rats, possibly through enhancing VEGF signaling and reducing angiostatin.

Imbalance between angiogenic and anti-angiogenic factors in sera from patients with large-vessel vasculitis.

OBJECTIVES: To investigate serum levels of a panel of angiogenic inducers (VEGF, FGF-2, Angiopoietin 1, -2, soluble VCAM-1) and inhibitors (angiostatin, endostatin, pentraxin-3) in patients with giant cell arteritis (GCA) and Takayasu's arteritis (TAK), in order to gain further insights into the molecular mechanisms driving angiogenesis dysregulation in large-vessel vasculitis (LVV). METHODS: Sera were obtained from 33 TAK patients and 14 GCA patients and from two groups of age-matched normal controls (NC). Disease activity was assessed using 18F-FDG PET/CT and clinical indices including NIH/Kerr criteria and ITAS. Angiogenic and anti-angiogenic factor serum levels were evaluated using commercial ELISA kits. Pentraxin 3 (PTX3) serum levels were evaluated by non-commercial ELISA, as already described. RESULTS: Among the angiogenic factors, only VEGF serum levels were significantly higher in TAK patients compared to NC. No difference was found between angiogenic factor levels in GCA patients compared to those detected in NC. Anti-angiogenic factor (Angiostatin, Endostatin, PTX3) serum levels were significantly higher in both GCA and TAK patients compared to NC. Significant associations were observed between VEGF and PTX3 levels and disease activity evaluated using PET scan and clinical indices. Cluster analysis based on PET scan scores in TAK patients showed significant ordered differences in VEGF and angiostatin serum levels. Indeed, we noted a progressive increase of VEGF and angiostatin from NC to the cluster including patients with the highest and more diffuse scan positivity. CONCLUSIONS: Our overall results demonstrate a circulating molecular profile characterised by a prevailing expression of anti-angiogenic soluble factors.

Urinary angiostatin: a novel biomarker of kidney disease associated with disease severity and progression.

BACKGROUND: This study aimed to evaluate the value of urinary angiostatin levels for assessing disease severity and progression of IgA nephropathy (IgAN). METHODS: Urinary angiostatin was identified as one of the distinct proteins in samples of patients with IgAN analyzed by Raybiotech protein array, and further confirmed by enzyme-linked immunosorbent assay (ELISA). RESULTS: Urinary angiostatin levels were significantly higher in IgAN patients than that in healthy controls (HC) subjects and lower than in disease controls (DC) patients. The concentrations of angiostatin in urine normalized to urinary creatinine (angiostatin/Cr) were positively associated with proteinuria level. With advancing chronic kidney disease (CKD) stage, urinary angiostatin/Cr levels were gradually increased. Urinary angiostatin/Cr levels in patients with Lee's grade IV-V were significantly higher than those in Lee's grade I-II and III. We further compared urinary angiostatin/Cr levels by using Oxford classification and found the expression in patients with mesangial proliferative score 1(M1) was significantly higher than that in M0 (P < 0.001). In addition, the levels of urinary angiostatin/Cr in patients with tubular atrophy/interstitial fibrosis score 1(T1) and T2 were significantly higher than those in T0 (P < 0.01, P < 0.001, respectively). After follow-up, renal survival was significantly worse in patients with higher levels of urinary angiostatin (P < 0.05). CONCLUSIONS: Urinary angiostatin may be a useful novel noninvasive biomarker to evaluate disease severity and progression of IgAN.

The Role of Fibrinolytic Regulators in Vascular Dysfunction of Systemic Sclerosis.

Systemic sclerosis (SSc) is a connective tissue disease of autoimmune origin characterized by vascular dysfunction and extensive fibrosis of the skin and visceral organs. Vascular dysfunction is caused by endothelial cell (EC) apoptosis, defective angiogenesis, defective vasculogenesis, endothelial-to-mesenchymal transition (EndoMT), and coagulation abnormalities, and exacerbates the disease. Fibrinolytic regulators, such as plasminogen (Plg), plasmin, α2-antiplasmin (α2AP), tissue-type plasminogen activator (tPA), urokinase-type plasminogen activator (uPA) and its receptor (uPAR), plasminogen activator inhibitor 1 (PAI-1), and angiostatin, are considered to play an important role in the maintenance of endothelial homeostasis, and are associated with the endothelial dysfunction of SSc. This review considers the roles of fibrinolytic factors in vascular dysfunction of SSc.

Effect of Diosmin Administration in Patients with Chronic Venous Disorders on Selected Factors Affecting Angiogenesis.

Diosmin is a natural compound with a wide range of biological activity, e.g., it improves lymphatic drainage, supports microcirculation, and increases venous tone, and venous elasticity, hence, it is applied in the pharmacotherapy of chronic venous disorders (CVD). The aim of this study was to assess the correlation between diosmin administration (2 × 600 mg daily) in patients suffering from CVD and the levels of selected factors influencing angiogenesis, which are involved in CVD pathophysiology. Thirty-five CVD patients were examined. Levels of plasma tumor necrosis factor alpha (TNF alpha), vascular endothelial growth factor (VEGF-A and VEGF-C); angiostatin, interleukin 6 (IL-6), fibroblast growth factor 2 (FGF2); and plasminogen (PLG) were measured with an Elisa assay before and after three months of diosmin administration. The clinical symptoms of CVD were monitored using ultrasound images, echo Doppler assay, visual analogue scale (VAS), and measurement of the leg circumference. The average content of TNF alpha, VEGF-C, VEGF-A IL-6, and FGF2 decreased after the therapy with diosmin in a significant manner; with p < 0.001, p < 0.05, p < 0.05, p < 0.01, and p < 0.01, respectively, and a significant (p < 0.05) increase in the plasma angiostatin level after the three-month treatment was found. A significant (p < 0.05) decrease in edema and the average leg circumference of the patients was observed after the therapy. Diosmin influences the angiogenic and inflammatory mechanisms involved in the pathophysiology of edema presented in patients with a different class of CVD.

Antiangiogenesis and medical therapy failure in intracranial atherosclerosis.

Intracranial atherosclerotic disease (ICAD) is one of the most common causes of stroke worldwide and the one with the worst prognosis. In this study, we assessed the hypothesis that the balance of circulating pro- and antiangiogenic factors plays a role in the evolution of the disease and can be used as a potential marker for the disease course and a target for treatment. Seventy-four patients with severe ICAD were enrolled in this prospective observational study, medically optimized, and followed for 6 months. Thirteen pro- and eight antiangiogenic factors were measured in the participants' serum using a sandwich multiplex ELISA. Angiogenic profiles were calculated using principal component analysis. We tested the association between angiogenic profiles and recurring cerebrovascular events despite intensive medical therapy, disability at 6 months after enrollment, and angiographic neovascularization in patients who failed medical treatment and underwent indirect revascularization surgery. There is a strong association between a functionally antiangiogenic profile and recurrent stroke or TIA in patients with ICAD (OR = 7.2, CI 2.4-34.4). Multivariable regression analysis showed that this antiangiogenic profile was also associated with poor functional status after 6 months (p = 0.002), independent from other clinical features such as history of previous stroke, diabetes, and age. In patients who failed medical management and underwent indirect revascularization surgery, high endostatin and angiostatin levels were also associated with low angiographic neovascularization (p = 0.02). The results of this study point to the striking importance of antiangiogenesis as a determinant of ICAD patient prognosis and suggest a possible new target for therapy.

Role of Angiogenesis in Chronic Radiation Proctitis: New Evidence Favoring Inhibition of Angiogenesis Ex Vivo.

BACKGROUND: Chronic radiation proctitis (CRP), a common complication after radiotherapy for pelvic malignancies, compromises patient quality of life. Vascular damage and aberrant angiogenesis in the mucosal layer are essential histological features, but changes to the submucosal layer are unclear. Thus, we evaluated the histological characteristics and distribution changes of key angiogenic factors in full-layered human CRP samples. METHODS: Thirty paraffin-embedded CRP and twenty-nine non-CRP tissues were used to evaluate histopathological changes. Immunohistochemistry with anti-CD34 antibody was performed to calculate microvascular density (MVD). Frozen tissues from eight CRP patients and five non-CRP controls were collected and analyzed by antibody array, which contained sixty human angiogenesis-related factors. Quality controls with positive and negative controls were performed during antibody array analysis. Two differentially expressed factors were confirmed by ELISA. RESULTS: CRP lesions showed vasculopathy, fibrosis, mucosal ulceration, edema, and inflammatory cell infiltration. Human angiogenesis antibody array and ELISA confirmed the increased angiostatin in CRP lesions. Immunohistochemical staining showed dispersed distribution of angiostatin throughout the mucosal and submucosal layers in CRP lesions, while angiostatin accumulated within the vessel lumens in non-CRP tissues. MVD significantly decreased in the submucosal layer of CRP, suggesting a potential association with increased angiostatin. CONCLUSIONS: Angiostatin increased and had a distinct distribution in CRP lesions. Compensatory telangiectasia in the mucosa, vessel stenosis, and reduced MVD might attenuate blood flow in the submucosa and contribute to CRP progression. Restoration of vascular functionality by promoting angiogenesis in the submucosal layer may help alleviate CRP in clinical practice.

Effect of titanium-prepared platelet-rich fibrin treatment on the angiogenic biomarkers in gingival crevicular fluid in infrabony defects of patients with chronic periodontitis: A randomized controlled clinical trial.

AIM: The aim of this double-blinded, randomized, controlled clinical study was to investigate the effect of titanium-prepared platelet-rich fibrin (T-PRF) treatment on the angiogenic biomarkers in gingival crevicular fluid (GCF) in infrabony defects of patients with chronic periodontitis. MATERIALS AND METHODS: Twenty five systemically healthy participants who complied with inclusion criteria with periodontal infrabony defects were recruited. In each patient, the infrabony defect of one side of arch was designated as control group (allograft), whereas the infrabony defect on the contralateral side of same arch was designated as test group (allograft + T-PRF). The therapy methods (test or control) were randomly decided. GCF samples were collected at baseline (presurgery) and then the 3rd, 7th, 14th, and 30th days after surgery. Platelet-derived growth factor (PDGF)-BB, vascular endothelial growth factor (VEGF)-A, fibroblast growth factor (FGF)-2, anjiogenin (ANG), angiostatin (ANT) in the GCF samples were measured using human enzyme-linked immunosorbent assay kits. RESULTS: In both groups, total amounts of PDGF-BB, VEGF-A, FGF-2, ANG, and ANT peaked in the GCF samples obtained at the early postoperative day (day 3) and decreased over time in the samples obtained at the 7th, 14th, and 30th days postsurgery. There were no significant differences between groups for the total amounts of PDGF-BB, VEGF-A, FGF-2, ANG, and ANT at all evaluation periods. CONCLUSION: Application of T-PRF combined with allograft in infrabony defects of patients with chronic periodontitis had no significant effects on angiogenic biomarkers in GCF.

Systemic lupus erythematosus biomarkers: the challenging quest.

SLE, a multisystem heterogeneous disease, is characterized by production of antibodies to cellular components, with activation of both the innate and the adaptive immune system. Decades of investigation of blood biomarkers has resulted in incremental improvements in the understanding of SLE. Owing to the heterogeneity of immune dysregulation, no single biomarker has emerged as a surrogate for disease activity or prediction of disease. Beyond identification of surrogate biomarkers, a multitude of clinical trials have sought to inhibit elevated SLE biomarkers for therapeutic benefit. Armed with new -omics technologies, the necessary yet daunting quest to identify better surrogate biomarkers and successful therapeutics for SLE continues with tenacity.

Negative regulators of angiogenesis: important targets for treatment of exudative AMD.

Angiogenesis contributes to the pathogenesis of many diseases including exudative age-related macular degeneration (AMD). It is normally kept in check by a tightly balanced production of pro- and anti-angiogenic factors. The up-regulation of the pro-angiogenic factor, vascular endothelial growth factor (VEGF), is intimately linked to the pathogenesis of exudative AMD, and its antagonism has been effectively targeted for treatment. However, very little is known about potential changes in expression of anti-angiogenic factors and the role they play in choroidal vascular homeostasis and neovascularization associated with AMD. Here, we will discuss the important role of thrombospondins and pigment epithelium-derived factor, two major endogenous inhibitors of angiogenesis, in retinal and choroidal vascular homeostasis and their potential alterations during AMD and choroidal neovascularization (CNV). We will review the cell autonomous function of these proteins in retinal and choroidal vascular cells. We will also discuss the potential targeting of these molecules and use of their mimetic peptides for therapeutic development for exudative AMD.

Poly(ADP-Ribose) Polymerase-1 (PARP-1) Inhibitors Reduce Reactive Gliosis and Improve Angiostatin Levels in Retina of Diabetic Rats.

Diabetic retinopathy (DR) is a multifactorial disease characterized by reactive gliosis and disbalance of angiogenesis regulators, contributing to endothelial dysfunction and microvascular complications. This study was organized to elucidate whether poly(ADP-ribose) polymerase-1 (PARP-1) inhibition could attenuate diabetes-induced damage to macroglia and correct angiogenic disbalance in diabetic rat retina. After 8 weeks of streptozotocin (STZ)-induced diabetes, Wistar male rats were treated with PARP-1 inhibitors, nicotinamide (NAm) or 3-aminobenzamide (3-AB) (100 and 30 mg/kg/daily i.p., respectively), for 14 days. After the 10-weeks experiment period, retinas were undergone an immunohistochemical staining for glial fibrillary acidic protein (GFAP), while western blots were performed to evaluate effects of PAPR-1 inhibitors on the levels of PARP-1, poly(ADP-ribosyl)ated proteins (PARs), GFAP, and angiostatin isoforms. Diabetes induced significant up-regulation and activation of retinal PARP-1, reactive gliosis development, and GFAP overexpression compared to non-diabetic control. Moreover, extensive fragmentation of both PARP-1 and GFAP (hallmarks of apoptosis and macroglia reactivation, respectively) in diabetic retina was also observed. Levels of angiostatin isoforms were dramatically decreased in diabetic retina, sustaining aberrant pro-angiogenic condition. Both NAm and 3-AB markedly attenuated damage to macroglia, evidenced by down-regulation of PARP-1, PARs and total GFAP compared to diabetic non-treated group. PARP-1-inhibitory therapy prevented formation of PARP-1 and GFAP cleavage-derived products. In retinas of anti-PARP-treated diabetic animals, partial restoration of angiostatin's levels was shown. Therefore, PARP-1 inhibitors counteract diabetes-induced injuries and manifest retinoprotective effects, including attenuation of reactive gliosis and improvement of angiogenic status, thus, such agents could be considered as promising candidates for DR management.

Different contributions of angiostatin and endostatin in angiogenesis impairment in systemic sclerosis: a cohort study.

OBJECTIVES: To determine the concentrations of circulating endostatin and angiostatin in patients with systemic sclerosis (SSc) and to assess its relationship to disease subsets, evolution phase, organ involvement and nailfold capillaroscopic changes. METHODS: Endostatin and angiostatin serum levels were measured by ELISA in a cohort of 57 patients with SSc, and correlated with disease subsets, evolution phase, organ involvement and nailfold capillaroscopic changes. RESULTS: Endostatin and angiostatin serum levels were significantly higher in patients with SSc than in healthy controls. Also, angiostatin was elevated in diffuse cutaneous SSc (dcSSc) and limited cutaneous SSc (lcSSc), but not in pre-SSc, while endostatin was increased in all SSc subsets. Moreover, endostatin was augmented in lcSSc, with or without CREST syndrome, whereas angiostatin was increased exclusively in patients with CREST. Analysis according to disease evolution phase found that endostatin was elevated in all phases while angiostatin was only significantly higher in intermediate and late phases of disease. Analysis regarding organ involvement revealed that angiostatin was significantly higher in patients with osteoarticular involvement and with more serious lung affection; no significant differences were found for endostatin. Finally, endostatin was significantly increased in all nailfold capillaroscopy stages, while angiostatin was only elevated in active and late phases. CONCLUSIONS: In accordance with previous studies, we found that endostatin and angiostatin concentrations are elevated in SSc patients. Additionally, we recognised the important role that endostatin might play as an early disease marker and realized that angiostatin is a marker of late disease and relates to lung disease severity.

Effect of the transdermal low-level laser therapy on endothelial function.

The effect of low-level laser therapy (LLLT) on the cardiovascular system is not fully established. Since the endothelium is an important endocrine element, establishing the mechanisms of LLLT action is an important issue.The aim of the study was to evaluate the effect of transdermal LLLT on endothelial function.In this study, healthy volunteers (n = 40, age = 20-40 years) were enrolled. N = 30 (14 female, 16 male, mean age 30 ± 5 years) constituted the laser-irradiated group (LG). The remaining 10 subjects (6 women, 4 men, mean age 28 ± 5 years) constituted the control group (CG). Participants were subjected to LLLT once a day for three consecutive days. Blood for biochemical assessments was drawn before the first irradiation and 24 h after the last session. In the LG, transdermal illumination of radial artery was conducted (a semiconductor laser λ = 808 nm, irradiation 50 mW, energy density 1.6 W/cm(2) and a dose 20 J/day, a total dose of 60 J). Biochemical parameters (reflecting angiogenesis: vascular endothelial growth factor (VEGF), fibroblast growth factor (FGF), angiostatin; antioxidative status: glutathione (GSH) and the nitric oxide metabolic pathway: symmetric dimethylarginine (SDMA), asymmetric dimethylarginine (ADMA) and L-arginine) were assessed. In the LG, a significant increase in GSH levels and considerable decrease in angiostatin concentration following the LLLT were observed. No significant differences in levels of the VEGF, FGF, SDMA, ADMA were observed.LLLT modifies vascular endothelial function by increasing its antioxidant and angiogenic potential. We found no significant differences in levels of the nitric oxide pathway metabolites within 24 h following the LLLT irradiation.

Pigment epithelium-derived factor mediates impaired lung vascular development in neonatal hyperoxia.

Bronchopulmonary dysplasia is a chronic lung disease of preterm infants characterized by arrested microvascularization and alveolarization. Studies show the importance of proangiogenic factors for alveolarization, but the importance of antiangiogenic factors is unknown. We proposed that hyperoxia increases the potent angiostatin, pigment epithelium-derived factor (PEDF), in neonatal lungs, inhibiting alveolarization and microvascularization. Wild-type (WT) and PEDF(-/-) mice were exposed to room air (RA) or 0.9 fraction of inspired oxygen from Postnatal Day 5 to 13. PEDF protein was increased in hyperoxic lungs compared with RA-exposed lungs (P < 0.05). In situ hybridization and immunofluorescence identified PEDF production primarily in alveolar epithelium. Hyperoxia reduced alveolarization in WT mice (P < 0.05) but not in PEDF(-/-) mice. WT hyperoxic mice had fewer platelet endothelial cell adhesion molecule (PECAM)-positive cells per alveolus (1.4 ± 0.4) than RA-exposed mice (4.3 ± 0.3; P < 0.05); this reduction was absent in hyperoxic PEDF(-/-) mice. The interactive regulation of lung microvascularization by vascular endothelial growth factor and PEDF was studied in vitro using MFLM-91U cells, a fetal mouse lung endothelial cell line. Vascular endothelial growth factor stimulation of proliferation, migration, and capillary tube formation was inhibited by PEDF. MFLM-91U cells exposed to conditioned medium (CM) from E17 fetal mouse lung type II (T2) cells cultured in 0.9 fraction of inspired oxygen formed fewer capillary tubes than CM from T2 cells cultured in RA (hyperoxia CM, 51 ± 10% of RA CM, P < 0.05), an effect abolished by PEDF antibody. We conclude that PEDF mediates reduced vasculogenesis and alveolarization in neonatal hyperoxia. Bronchopulmonary dysplasia likely results from an altered balance between pro- and antiangiogenic factors.