Vascular endothelial growth factor (VEGF) is released from platelets during blood clotting: implications for measurement of circulating VEGF levels in clinical disease

Plasma VEGFA and PGF impact longitudinal tau and cognition in preclinical Alzheimer's disease

Vascular dysfunction is increasingly recognized as an important contributor to the pathogenesis of Alzheimer's disease. Alterations in vascular endothelial growth factor (VEGF) pathways have been implicated as potential mechanisms. However, the specific impact of VEGF proteins in preclinical Alzheimer's disease and their relationships with other Alzheimer's disease and vascular pathologies during this critical early period remain to be elucidated. We included 317 older adults from the Harvard Aging Brain Study, a cohort of individuals who were cognitively unimpaired at baseline and followed longitudinally for up to 12 years. Baseline VEGF family protein levels (VEGFA, VEGFC, VEGFD, PGF and FLT1) were measured in fasting plasma using high-sensitivity immunoassays. Using linear mixed effects models, we examined the interactive effects of baseline plasma VEGF proteins and amyloid PET burden (Pittsburgh Compound-B) on longitudinal cognition (Preclinical Alzheimer Cognitive Composite-5). We further investigated if effects on cognition were mediated by early neocortical tau accumulation (flortaucipir PET burden in the inferior temporal cortex) or hippocampal atrophy. Lastly, we examined the impact of adjusting for baseline cardiovascular risk score or white matter hyperintensity volume. Baseline plasma VEGFA and PGF each showed a significant interaction with amyloid burden on prospective cognitive decline. Specifically, low VEGFA and high PGF were associated with greater cognitive decline in individuals with elevated amyloid, i.e. those on the Alzheimer's disease continuum. Concordantly, low VEGFA and high PGF were associated with accelerated longitudinal tau accumulation in those with elevated amyloid. Moderated mediation analyses confirmed that accelerated tau accumulation fully mediated the effects of low VEGFA and partially mediated (31%) the effects of high PGF on faster amyloid-related cognitive decline. The effects of VEGFA and PGF on tau and cognition remained significant after adjusting for cardiovascular risk score or white matter hyperintensity volume. There were concordant but non-significant associations with longitudinal hippocampal atrophy. Together, our findings implicate low VEGFA and high PGF in accelerating early neocortical tau pathology and cognitive decline in preclinical Alzheimer's disease. Additionally, our results underscore the potential of these minimally-invasive plasma biomarkers to inform the risk of Alzheimer's disease progression in the preclinical population. Importantly, VEGFA and PGF appear to capture distinct effects from vascular risks and cerebrovascular injury. This highlights their potential as new therapeutic targets, in combination with anti-amyloid and traditional vascular risk reduction therapies, to slow the trajectory of preclinical Alzheimer's disease and delay or prevent the onset of cognitive decline.

The effect of exercise on blood concentrations of angiogenesis markers in older adults: A systematic review and meta-analysis

Impaired angiogenesis is associated with cognitive decline in older adults. While exercise has been broadly associated with increased angiogenesis, the relevant mechanisms in older adults are not clear. Here, we present a systematic review and meta-analysis on the relationship between exercise and specific blood angiogenesis markers in older adults to better understand the relevant mechanisms. MEDLINE, Embase, and Cochrane CENTRAL were searched for original reports of angiogenesis markers' concentrations in blood before and after exercise in older adults (≥50 years). Heterogeneity was investigated using sub-group analyses and meta-regressions. Of the 44 articles included in the review, 38 were included in the meta-analyses for five markers: vascular endothelial growth factor (VEGF), e-selectin (CD62E), endostatin, fibroblast growth factor 2, and matrix metallopeptidase-9. VEGF levels were higher (SMD[95%CI]= 0.18[0.03, 0.34], and CD62E levels were lower (SMD[95%CI]= -0.72[-1.42, -0.03], p = 0.04) after exercise. No other markers were altered. Although more studies are needed, changes in angiogenesis markers may help explain the beneficial effects of exercise on angiogenesis in older adults.

A novel multiplex biomarker panel for profiling human acute and chronic kidney disease

Acute and chronic kidney disease continues to confer significant morbidity and mortality in the clinical setting. Despite high prevalence of these conditions, few validated biomarkers exist to predict kidney dysfunction. In this study, we utilized a novel kidney multiplex panel to measure 21 proteins in plasma and urine to characterize the spectrum of biomarker profiles in kidney disease. Blood and urine samples were obtained from age-/sex-matched healthy control subjects (HC), critically-ill COVID-19 patients with acute kidney injury (AKI), and patients with chronic or end-stage kidney disease (CKD/ESKD). Biomarkers were measured with a kidney multiplex panel, and results analyzed with conventional statistics and machine learning. Correlations were examined between biomarkers and patient clinical and laboratory variables. Median AKI subject age was 65.5 (IQR 58.5-73.0) and median CKD/ESKD age was 65.0 (IQR 50.0-71.5). Of the CKD/ESKD patients, 76.1% were on hemodialysis, 14.3% of patients had kidney transplant, and 9.5% had CKD without kidney replacement therapy. In plasma, 19 proteins were significantly different in titer between the HC versus AKI versus CKD/ESKD groups, while NAG and RBP4 were unchanged. TIMP-1 (PPV 1.0, NPV 1.0), best distinguished AKI from HC, and TFF3 (PPV 0.99, NPV 0.89) best distinguished CKD/ESKD from HC. In urine, 18 proteins were significantly different between groups except Calbindin, Osteopontin and TIMP-1. Osteoactivin (PPV 0.95, NPV 0.95) best distinguished AKI from HC, and β2-microglobulin (PPV 0.96, NPV 0.78) best distinguished CKD/ESKD from HC. A variety of correlations were noted between patient variables and either plasma or urine biomarkers. Using a novel kidney multiplex biomarker panel, together with conventional statistics and machine learning, we identified unique biomarker profiles in the plasma and urine of patients with AKI and CKD/ESKD. We demonstrated correlations between biomarker profiles and patient clinical variables. Our exploratory study provides biomarker data for future hypothesis driven research on kidney disease.

Signaling roles of platelets in skeletal muscle regeneration

Platelets have important hemostatic functions in repairing blood vessels upon tissue injury. Cytokines, growth factors, and metabolites stored in platelet α-granules and dense granules are released upon platelet activation and clotting. Emerging evidence indicates that such platelet-derived signaling factors are instrumental in guiding tissue regeneration. Here, we discuss the important roles of platelet-secreted signaling factors in skeletal muscle regeneration. Chemokines secreted by platelets in the early phase after injury are needed to recruit neutrophils to injured muscles, and impeding this early step of muscle regeneration exacerbates inflammation at later stages, compromises neo-angiogenesis and the growth of newly formed myofibers, and reduces post-injury muscle force production. Platelets also contribute to the recruitment of pro-regenerative stromal cells from the adipose tissue, and the platelet releasate may also regulate the metabolism and proliferation of muscle satellite cells, which sustain myogenesis. Therefore, harnessing the signaling functions of platelets and the platelet secretome may provide new avenues for promoting skeletal muscle regeneration in health and disease.

Mean platelet volume, thrombocytosis, and survival in non-small cell lung cancer patients treated with first-line pembrolizumab alone or with chemotherapy

INTRODUCTION

Patients treated with immune checkpoint inhibitors (ICIs) may not response to treatment and are at risk for immune-related adverse events (irAEs). Platelet function has been linked to both oncogenesis and immune evasion. We studied the association between the change in mean platelet volume (MPV), platelet count, survival, and the risk of developing irAEs in patients with metastatic non-small cell lung cancer (NSCLC) who have received first-line ICI.

METHODS

In this retrospective study, delta (∆) MPV was defined as the difference between cycle 2 and baseline MPV. Patient data were collected via chart review, and Cox proportional hazard and Kaplan-Meier method were used to assess the risk and estimate median overall survival.

RESULTS

We identified 188 patients treated with first-line pembrolizumab, with or without concurrent chemotherapy. There were 80 (42.6%) patients received pembrolizumab monotherapy, and 108 (57.4%) received pembrolizumab in combination with platinum-based chemotherapy. Patients whose MPV (∆MPV ≤ 0) decreased had hazard ratio (HR) = 0.64 (95% CI 0.43-0.94) for death with p = 0.023. Patients with ∆MPV ≤ - 0.2 fL (median), there was a 58% increase in the risk of developing irAE (HR = 1.58, 95% CI 1.04-2.40, p = 0.031). Thrombocytosis at baseline and cycle 2 was associated with shorter OS with p = 0.014 and 0.039, respectively.

CONCLUSION

Change in MPV after 1 cycle of pembrolizumab-based treatment was significantly associated with overall survival as well as the occurrence of irAEs in patients with metastatic NSCLC in the first-line setting. In addition, thrombocytosis was associated with poor survival.

Podoplanin and CLEC-2 levels in patients with COVID-19

Introduction

Podoplanin (PDPN gene) and CLEC-2 are involved in inflammatory hemostasis and have also been related with the pathogenesis of thrombosis. Emerging evidence also suggest that podoplanin can exert protective effects in sepsis and in acute lung injury. In lungs, podoplanin is co-expressed with ACE2, which is the main entry receptor for SARS-CoV-2.

Aim

To explore the role of podoplanin and CLEC-2 in COVID-19.

Methods

Circulating levels of podoplanin and CLEC-2 were measured in 30 consecutive COVID-19 patients admitted due to hypoxia, and in 30 age- and sex-matched healthy individuals. Podoplanin expression in lungs from patients who died of COVID-19 was obtained from two independent public databases of single-cell RNAseq from which data from control lungs were also available.

Results

Circulating podoplanin levels were lower in COVID-19, while no difference was observed in CLEC-2 levels. Podoplanin levels were significantly inversely correlated with markers of coagulation, fibrinolysis and innate immunity. scRNAseq data confirmed that PDPN is co-expressed with ACE2 in pneumocytes, and showed that PDPN expression is lower in this cell compartment in lungs from patients with COVID-19.

Conclusion

Circulating levels of podoplanin are lower in COVID-19, and the magnitude of this reduction is correlated with hemostasis activation. We also demonstrate the downregulation of PDPN at the transcription level in pneumocytes. Together, our exploratory study questions whether an acquired podoplanin deficiency could be involved in the pathogenesis of acute lung injury in COVID-19, and warrant additional studies to confirm and refine these findings.

The effect of exercise on blood concentrations of angiogenesis markers in older adults: a systematic review and meta-analysis

Background

Physical exercise has positive impacts on health and can improve angiogenesis, which is impaired during aging, but the underlying mechanisms of benefit are unclear. This meta-analysis and systematic review investigated the effects of exercise on several peripheral angiogenesis markers in older adults to better understand the relationship between exercise and angiogenesis.

Methods

MEDLINE, Embase, and Cochrane CENTRAL were searched for original, peer-reviewed reports of peripheral concentrations of angiogenesis markers before and after exercise interventions in older adults (> 50 years). The risk of bias was assessed with standardized criteria. Standardized mean differences (SMD) with 95% confidence intervals (CIs) were calculated from random-effects models. Publication bias was assessed with Egger's test, funnel plots, and trim-and-fill. A priori subgroup analyses and meta-regressions were performed to investigate heterogeneity where possible.

Results

Of the 44 articles included in the review, 38 were included in meta-analyses for five proteins. Vascular endothelial growth factor (VEGF) was found to be higher after exercise (SMD[95%CI] = 0.18[0.03, 0.34], p = 0.02), and e-selectin (CD62E) was found to be lower after exercise (SMD[95%CI]= -0.72[-1.42, -0.03], p = 0.04). Endostatin (SMD[95%CI] = 0.28[-0.56, 1.11], p = 0.5), fibroblast growth factor 2 (SMD[95%CI] = 0.03[-0.18, 0.23], p = 0.8), and matrix metallopeptidase-9 (SMD[95%CI] = -0.26[-0.97, 0.45], p = 0.5) levels did not change after exercise.

Conclusions

Of the five angiogenesis blood markers evaluated in this meta-analysis, only VEGF and CD62E changed with exercise. Although more studies are needed, changes in angiogenesis markers may explain the beneficial effects of exercise on angiogenesis and health in older adults.

The impact of VEGF on cancer metastasis and systemic disease

Metastasis is the leading cause of cancer-associated mortality and the underlying mechanisms of cancer metastasis remain elusive. Both blood and lymphatic vasculatures are essential structures for mediating distal metastasis. The vasculature plays multiple functions, including accelerating tumor growth, sustaining the tumor microenvironment, supplying growth and invasive signals, promoting metastasis, and causing cancer-associated systemic disease. VEGF is one of the key angiogenic factors in tumors and participates in the initial stage of tumor development, progression and metastasis. Consequently, VEGF and its receptor-mediated signaling pathways have become one of the most important therapeutic targets for treating various cancers. Today, anti-VEGF-based antiangiogenic drugs (AADs) are widely used in the clinic for treating different types of cancer in human patients. Despite nearly 20-year clinical experience with AADs, the impact of these drugs on cancer metastasis and systemic disease remains largely unknown. In this review article, we focus our discussion on tumor VEGF in cancer metastasis and systemic disease and mechanisms underlying AADs in clinical benefits.

Fabrication of succinate-alginate xerogel films for in vitro coupling of osteogenesis and neovascularization

The osseointegration of metallic implants is reliant on a cascade of molecular interactions and the delivery of macromolecules to the implant environment that occurs before substantial bone formation. Early blood vessel formation is a requisite first step in the healing timeline for osteoid formation, where vascular development can be accelerated as a result of controlled hypoxic conditioning. In this study, alginate-derived xerogel films containing varied concentrations of disodium succinate salt which has been shown to induce pseudohypoxia (short-term hypoxic effects while maintaining an oxygenated environment) were developed. Xerogels were characterized for their morphology, succinate release over time and cellular response with osteoblast-mimicking Saos-2 and human umbilical vein endothelial cells (HUVEC). Scanning electron microscopy revealed a multiscale topography that may favour osseointegration and alamarBlue assays indicated no cytotoxic effects during in vitro proliferation of Saos-2 cells. pH measurements of eluted succinate reach 95 % of peak value after 7 h of immersion for all gels containing 10 mM of succinate or less, and 60 % within the first 40 min. In vitro exposure of HUVECs to succinate-conditioned media increased the net concentration of total proteins measured by bicinchoninic acid (BCA) assay and maintains stable vascular endothelial growth factor (VEGF) and extracellular platelet-derived growth factor (PDGF) for vessel formation through comparison of enzyme-linked immunosorbent assays (ELISAs) of the culture media and cell lysate. Tube formation assays also showed a sustained increase in tube diameter across the first 48 h of HUVEC culture when succinate concentrations of 1 and 10 μM in the xerogel. Overall, the succinate-alginate films serve as a prospective organic coating for bone-interfacing implant materials which may induce temporary pseudohypoxic conditions favourable for early angiogenesis and bone regeneration in vivo at succinate concentrations of 1 or 10 μM.

Paracrine Factors of Stressed Peripheral Blood Mononuclear Cells Activate Proangiogenic and Anti-Proteolytic Processes in Whole Blood Cells and Protect the Endothelial Barrier

Tissue-regenerative properties have been attributed to secreted paracrine factors derived from stem cells and other cell types. In particular, the secretome of γ-irradiated peripheral blood mononuclear cells (PBMCsec) has been shown to possess high tissue-regenerative and proangiogenic capacities in a variety of preclinical studies. In light of future therapeutic intravenous applications of PBMCsec, we investigated the possible effects of PBMCsec on white blood cells and endothelial cells lining the vasculature. To identify changes in the transcriptional profile, whole blood was drawn from healthy individuals and stimulated with PBMCsec for 8 h ex vivo before further processing for single-cell RNA sequencing. PBMCsec significantly altered the gene signature of granulocytes (17 genes), T-cells (45 genes), B-cells (72 genes), and, most prominently, monocytes (322 genes). We detected a strong upregulation of several tissue-regenerative and proangiogenic cyto- and chemokines in monocytes, including VEGFA, CXCL1, and CXCL5. Intriguingly, inhibitors of endopeptidase activity, such as SERPINB2, were also strongly induced. Measurement of the trans-endothelial electrical resistance of primary human microvascular endothelial cells revealed a strong barrier-protective effect of PBMCsec after barrier disruption. Together, we show that PBMCsec induces angiogenic and proteolytic processes in the blood and is able to attenuate endothelial barrier damage. These regenerative properties suggest that systemic application of PBMCsec might be a promising novel strategy to restore damaged organs.

A systematic review and meta-analysis of preanalytical factors and methodological differences influencing the measurement of circulating vascular endothelial growth factor

Background

Intraocular treatment with antibodies targeting vascular endothelial growth factor (anti-VEGF) inhibits pathological vessel growth in adults and preterm infants. Recently, concerns regarding the impact of anti-VEGF treatment on systemic VEGF levels in preterm infants have been raised. Earlier studies suggest that preanalytical and methodological parameters impact analytical VEGF concentrations, but we have not found a comprehensive systematic review covering preanalytical procedures and methods for VEGF measurements.

Objective

This review aimed to evaluate the most critical factors during sample collection, sample handling, and the analytical methods that influence VEGF levels and therefore should be considered when planning a prospective collection of samples to get reproducible, comparable results.

Material and methods

PubMed and Scopus databases were searched 2021/Nov/11. In addition, identification of records via other methods included reference, citation, and Google Scholar searches. Rayyan QCRI was used to handle duplicates and the selection process. Publications reporting preanalytical handling and/or methodological comparisons using human blood samples were included. Exclusion criteria were biological, environmental, genetic, or physiological factors affecting VEGF. The data extraction sheets included bias assessment using the QUADAS-2 tool, evaluating patient selection, index-test, reference standard, and flow and timing. Concentrations of VEGF and results from statistical comparisons of analytical methods and/or preanalytical sample handling and/or different sample systems were extracted. The publications covering preanalytical procedures were further categorized based on the stage of the preanalytical procedure. Meta-analysis was used to visualize VEGF concentrations among healthy individuals. The quality of evidence was rated according to GRADE.

Results

We identified 1596 publications, and, after the screening process, 43 were considered eligible for this systematic review. The risk of bias estimation was difficult for 2/4 domains due to non-reported information. Four critical steps in the preanalytical process that impacted VEGF quantification were identified: blood drawing and the handling before, during, and after centrifugation. Sub-categorization of those elements resulted in nine findings, rated from moderate to very low evidence grade. The choice of sample system was the most reported factor. VEGF levels (mean [95% CI]) in serum (n = 906, 20 publications), (252.5 [213.1–291.9] pg/mL), were approximated to ninefold higher than in plasma (n = 1122, 23 publications), (27.8 [23.6–32.1] pg/mL), based on summarized VEGF levels with meta-analysis. Notably, most reported plasma levels were below the calibration range of the used method.

Conclusion

When measuring circulating VEGF levels, choice of sample system and sample handling are important factors to consider for ensuring high reproducibility and allowing study comparisons. Protocol: CRD42020192433

A comparative profile of total protein and six angiogenically-active growth factors in three platelet products

OBJECTIVES

Platelet-derived products have been shown as promising novel therapeutic agents for chronic wounds. However, their clinical use requires a greater degree of method standardisation, part of which involved more extensive cataloguing of their biochemical composition. This study aimed to quantify and compare total protein and 6 angiogenically-active growth factors in three distinct platelet products.

METHODS

Platelet Lysate (PL, n=5), Calcium-activated Platelet Rich Plasma (Ca-PRP, n=5) and Platelet-Rich Fibrin (PRF, n=5) were prepared from pooled platelet apheresis products (n=10). Ca-PRP and PRF were prepared from the same units (n=5) by activation with 20 mmolL^-1 calcium chloride. PL was prepared from the remaining (n=5) units using an established lysate. Total protein was quantified with the Bradford Assay. Sandwich enzyme-linked immunosorbent assay was used to quantify six growth factors: epidermal growth factor (EGF), vascular endothelial growth factor (VEGF), hepatocyte growth factor (HGF), stromal cell derived growth factor-1α (SDF-1α), endostatin, and transforming growth factor-β1 (TGF-β1).

RESULTS

Protein retrieval differed significantly (p<0.05) between the three products: PL (11.35±0.80 mg/mL) < Ca-PRP (20.44±8.17 mg/mL) < PRF (40.67±3.13 mg/mL). Growth factor yield was considerable in all three products and differed significantly for: VEGF (PL<PRF); EGF (Ca-PRP<PRF); HFG (PL<Ca-PRP); Endostatin (PL<Ca-PRP, PRF<Ca-PRP, PL<PRF) and TGF-β1 (Ca-PRP<PL, Ca-PRP<PRF).

CONCLUSIONS

Platelet apheresis products contain a substantial quantity of the investigated pro- and anti-angiogenic growth factors. Their release varies depending on the manufacturing protocol used. Clinically, alternate products could thus be combined to provide a therapeutically optimal mix of growth factors.

Imaging Markers Associated With Radiation-Induced Changes in Brain Arteriovenous Malformations After Radiosurgery

BACKGROUND

Radiation-induced changes (RICs) in brain tissue, seen as increased perinidal T2-weighted hyperintensity on MRI, are commonly observed in patients with brain arteriovenous malformations (BAVMs) within 2 years after Gamma Knife (Elekta) radiosurgery (GKRS).

OBJECTIVE

To explore the imaging markers associated with RICs in patients with BAVMs.

METHODS

We retrospectively included 106 treatment-naïve patients with BAVMs who received GKRS alone between 2011 and 2018 and had ≥24 months of clinical and MRI follow-up. Pre-GKRS angiography and MRIs were analyzed for morphological characteristics and quantitative digital subtraction angiography parameters. RIC severity was categorized as mild (grade I), moderate (grade II), or severe (grade III). Firth logistic regression analysis was conducted to determine the associations between the parameters and RICs.

RESULTS

Among the 106 patients, 83 (78.3%) developed RICs, with 16 categorized as grade I, 62 as grade II, and 5 as grade III. RICs were symptomatic in 19 patients (17.9%). In multivariable models, BAVMs with a volume of >5 cm3 (odds ratio [OR]: 4.322, P = .024) and neoangiogenesis on angiography before treatment (OR: 3.846, P = .029), and thrombus within nidus or drainage vein on follow-up MRI (OR: 3.679, P = .001) were independently associated with grade II or III RICs. Symptomatic RICs were more likely to develop in basal ganglia or brainstem.

CONCLUSION

Large BAVMs and neoangiogenesis were associated with moderate to severe RICs in treatment-naïve patients with BAVMs. Our findings may assist with the complication risk assessment for these patients.

The Effects of Acute Cardiovascular Exercise on Memory and Its Associations With Exercise-Induced Increases in Neurotrophic Factors

Due to increasing life expectancy, low-cost interventions to counteract age-related memory impairment have gained popularity. Physical activity has been shown to positively affect memory and hippocampal plasticity in rodents and humans. These effects have been proposed to be mediated by the release of neurotrophic factors. However, studies examining the effects of a single cardiovascular exercise session on human memory have yielded conflicting results. Moreover, it remains unclear whether exercise-induced memory enhancements are related to changes in peripheral neurotrophic factor concentrations. The present study tested whether one bout of cardiovascular exercise during an early phase of memory consolidation, compared to one bout of stretching and toning, positively affected memory. Furthermore, it was analyzed whether exercise-induced changes in the brain-derived neurotrophic factor (BDNF) and vascular endothelial growth factor (VEGF) were related to memory enhancement after a single bout of physical exercise. Fifty healthy participants (20–40 years) were randomly assigned to either a cycling group (BIKE) or a stretching and toning group (STRETCH). Participants performed an implicit vocabulary learning task which was immediately followed by physical exercise. Memory for the learned vocabulary was tested 1–2 weeks later. To measure exercise-induced changes in serum neurotrophic factor levels, blood samples were collected at rest (baseline) and immediately after the exercise session. Results did not show a significant difference in memory between the BIKE group and the STRETCH group. However, in the BIKE group, a larger increase in BDNF and VEGF levels was observed than in the STRETCH group. Moreover, the increase in BDNF and memory performance tended to be positively related in the BIKE group. We speculate that the correlation between exercise-increased BDNF levels and memory in the cycling group may indicate an involvement of BDNF in mediating memory processes after acute cardiovascular exercise.

Melatonin as an Adjuvant to Antiangiogenic Cancer Treatments

Melatonin is a hormone with different functions, antitumor actions being one of the most studied. Among its antitumor mechanisms is its ability to inhibit angiogenesis. Melatonin shows antiangiogenic effects in several types of tumors. Combination of melatonin and chemotherapeutic agents have a synergistic effect inhibiting angiogenesis. One of the undesirable effects of chemotherapy is the induction of pro-angiogenic factors, whilst the addition of melatonin is able to overcome these undesirable effects. This protective effect of the pineal hormone against angiogenesis might be one of the mechanisms underlying its anticancer effect, explaining, at least in part, why melatonin administration increases the sensitivity of tumors to the inhibitory effects exerted by ordinary chemotherapeutic agents. Melatonin has the ability to turn cancer totally resistant to chemotherapeutic agents into a more sensitive chemotherapy state. Definitely, melatonin regulates the expression and/or activity of many factors involved in angiogenesis which levels are affected (either positively or negatively) by chemotherapeutic agents. In addition, the pineal hormone has been proposed as a radiosensitizer, increasing the oncostatic effects of radiation on tumor cells. This review serves as a synopsis of the interaction between melatonin and angiogenesis, and we will outline some antiangiogenic mechanisms through which melatonin sensitizes cancer cells to treatments, such as radiotherapy or chemotherapy.

Decreased Platelet Counts and Serum Levels of VEGF-A, PDGF-BB, and BDNF in Extremely Preterm Infants Developing Severe ROP

INTRODUCTION

Thrombocytopenia has been identified as an independent risk factor for retinopathy of prematurity (ROP), although underlying mechanisms are unknown. In this study, the association of platelet count and serum platelet-derived factors with ROP was investigated.

METHODS

Data for 78 infants born at gestational age (GA) <28 weeks were included. Infants were classified as having no/mild ROP or severe ROP. Serum levels of vascular endothelial growth factor A, platelet-derived growth factor BB, and brain-derived neurotrophic factor were measured in serum samples collected from birth until postmenstrual age (PMA) 40 weeks. Platelet counts were obtained from samples taken for clinical indication.

RESULTS

Postnatal platelet counts and serum concentrations of the 3 growth factors followed the same postnatal pattern, with lower levels in infants developing severe ROP at PMA 32 and 36 weeks (p < 0.05-0.001). With adjustment for GA, low platelet counts and low serum concentrations of all 3 factors at PMA 32 weeks were significantly associated with severe ROP. Serum concentrations of all 3 factors also strongly correlated with platelet count (p < 0.001).

CONCLUSION

In this article, we show that ROP, platelet counts, and specific pro-angiogenic factors correlate. These data suggest that platelet-released factors might be involved in the regulation of retinal and systemic angiogenesis after extremely preterm birth. Further investigations are needed.

The Role of Anti-angiogenesis in the Treatment Landscape of Non-small Cell Lung Cancer - New Combinational Approaches and Strategies of Neovessel Inhibition

Tumor progression depends primarily on vascular supply, which is facilitated by angiogenic activity within the malignant tissue. Non-small cell lung cancer (NSCLC) is a highly vascularized tumor, and inhibition of angiogenesis was projected to be a promising therapeutic approach. Over a decade ago, the first anti-angiogenic agents were approved for advanced stage NSCLC patients, however, they only produced a marginal clinical benefit. Explanations why anti-angiogenic therapies only show modest effects include the highly adaptive tumor microenvironment (TME) as well as the less understood characteristics of the tumor vasculature. Today, advanced methods of in-depth characterization of the NSCLC TME by single cell RNA sequencing (scRNA-Seq) and preclinical observations enable a detailed characterization of individual cancer landscapes, allowing new aspects for a more individualized inhibition of angiogenesis to be identified. Furthermore, the tumor vasculature itself is composed of several cellular subtypes, which closely interact with other cellular components of the TME, and show distinct biological functions such as immune regulation, proliferation, and organization of the extracellular matrix. With these new insights, combinational approaches including chemotherapy, anti- angiogenic and immunotherapy can be developed to yield a more target-oriented anti-tumor treatment in NSCLC. Recently, anti-angiogenic agents were also shown to induce the formation of high endothelial venules (HEVs), which are essential for the formation of tertiary lymphoid structures, and key components in triggering anti-tumor immunity. In this review, we will summarize the current knowledge of tumor-angiogenesis and corresponding anti-angiogenic therapies, as well as new aspects concerning characterization of tumor-associated vessels and the resulting new strategies for anti-angiogenic therapies and vessel inhibition in NSCLC. We will further discuss why anti-angiogenic therapies form an interesting backbone strategy for combinational therapies and how anti-angiogenic approaches could be further developed in a more personalized tumor-oriented fashion with focus on NSCLC.

Unanticipated 30-day readmission following rectosigmoid resection at the time of cytoreductive surgery in patients with advanced stage ovarian cancer

The objective of this study was to examine the rate of and indications for readmission in patients with advanced staged ovarian cancer undergoing rectosigmoid resection and primary anastomosis, an important quality metric. A retrospective review was conducted of patients with primary ovarian cancer who underwent rectosigmoid resection as part of cytoreductive surgery between July 2003 and July 2014. Univariate analysis identified rates and predictors of readmission. Fifty patients were eligible for analysis. The unanticipated 30-day readmission rate was 18% (n = 9). Of those readmitted less than 30 days from date of discharge, 3 were readmitted more than once, making 14 total readmissions. A total of 21 indications for readmission were reported, with the most common being: infection (23.8%, n = 5); thromboembolic events (19%, n = 4); and severe malnutrition (14.3%, n = 3). The median time to readmission was 14 days (range, 2-26). There were no deaths within 30 days of surgery in this cohort.IMPACT STATEMENTWhat is already known about the subject? Unanticipated 30-day readmission rates are reported to be between 12 and 20% among patients undergoing cytoreductive surgery for the management of ovarian cancer. The relative contribution of rectosigmoid resection at the time of cytoreductive surgery to readmission is not well studied.What do the results of this study add? In the examined cohort, the unanticipated 30-day readmission rate following rectosigmoid resection with primary reanastomosis at the time of cytoreductive surgery is 18%, similar to the readmission rate for patients undergoing cytoreductive surgery, in general. While the sample size is limited, the perioperative complications in this cohort appear similar to those of patients undergoing cytoreductive surgery.What are the implications of these findings for clinical practice and/or further research? Efforts to reduce unanticipated 30-day readmission following cytoreductive surgery is warranted. Future studies may benefit from multi-centre approaches and prospective data collection, while simultaneously assessing the impact of enhanced recovery programs. Ultimately, identification of risk factors, and programmatic initiatives to drive down readmission will be important across surgical platforms, and the opportunity exists in patients with advanced stage ovarian cancer.

COVID-19-Induced Neurovascular Injury: a Case Series with Emphasis on Pathophysiological Mechanisms

Coronavirus disease 2019 (COVID-19) is associated with a high inflammatory burden that can induce severe respiratory disease among other complications; vascular and neurological damage has emerged as a key threat to COVID-19 patients. Risk of severe infection and mortality increases with age, male sex, and comorbidities including cardiovascular disease, hypertension, obesity, diabetes, and chronic pulmonary disease. We review clinical and neuroradiological findings in five patients with COVID-19 who suffered severe neurological disease and illustrate the pathological findings in a 7-year-old boy with COVID-19-induced encephalopathy whose brain tissue sample showed angiocentric mixed mononuclear inflammatory infiltrate. We summarize the structural and functional properties of the virus including the molecular processes that govern the binding to its membrane receptors and cellular entry. In addition, we review clinical and experimental evidence in patients and animal models that suggests coronaviruses enter into the central nervous system (CNS), either via the olfactory bulb or through hematogenous spread. We discuss suspected pathophysiological mechanisms including direct cellular infection and associated recruitment of immune cells and neurovirulence, at least in part, mediated by cytokine secretion. Moreover, contributing to the vascular and neurological injury, coagulopathic disorders play an important pathogenic role. We survey the molecular events that contribute to the thrombotic microangiopathy. We describe the neurological complications associated with COVID-19 with a focus on the potential mechanisms of neurovascular injury. Our thesis is that following infection, three main pathophysiological processes-inflammation, thrombosis, and vascular injury-are responsible for the neurological damage and diverse pathology seen in COVID-19 patients.

Lower plasma vascular endothelial growth factor A in major depressive disorder not normalized after antidepressant treatment: A case control study

OBJECTIVE

Vascular endothelial growth factor A is a growth factor with pro-angiogenic and neurotrophic properties. Anti-vascular endothelial growth factor A treatments, used to treat cancers and opthalmic diseases, are known to induce depressive symptoms. Thus, we hypothesized that vascular endothelial growth factor A plasma levels are low in patients experiencing a major depressive episode in the context of major depressive disorder, which consequently increase after antidepressant treatment. The aim of this study was to compare plasma vascular endothelial growth factor A levels in patients with major depressive episode-major depressive disorder before and after antidepressant treatment.

METHODS

Vascular endothelial growth factor A fasting plasma levels of 469 major depressive episode-major depressive disorder patients were compared with healthy controls. Depressed patients were assessed for remission after 3 and 6 months of antidepressant treatment. Bivariate and multivariate analyses adjusted for sex, age, body mass index and tobacco use were performed.

RESULTS

As compared to healthy controls, major depressive episode patients had lower vascular endothelial growth factor A, 66.0 (38.3) pg/mL (standard deviation) vs 83.2 (49.2) pg/mL, p < 0.0001. Plasma vascular endothelial growth factor A levels did not change after antidepressant treatment, even in remitters, and remained lower than those of healthy controls, 64.9 (39.3) pg/mL vs 83.2 (49.2) pg/mL, p < 0.0001.

CONCLUSION

Depressed patients with major depressive disorder have lower plasma vascular endothelial growth factor A levels than healthy controls during their major depressive episode and after remission following antidepressant treatment. New strategies targeting enhancement of plasma vascular endothelial growth factor A could be promising for the prevention and treatment of major depressive disorder.

Restoration of Neurological Function Following Peripheral Nerve Trauma

Following peripheral nerve trauma that damages a length of the nerve, recovery of function is generally limited. This is because no material tested for bridging nerve gaps promotes good axon regeneration across the gap under conditions associated with common nerve traumas. While many materials have been tested, sensory nerve grafts remain the clinical “gold standard” technique. This is despite the significant limitations in the conditions under which they restore function. Thus, they induce reliable and good recovery only for patients < 25 years old, when gaps are <2 cm in length, and when repairs are performed <2–3 months post trauma. Repairs performed when these values are larger result in a precipitous decrease in neurological recovery. Further, when patients have more than one parameter larger than these values, there is normally no functional recovery. Clinically, there has been little progress in developing new techniques that increase the level of functional recovery following peripheral nerve injury. This paper examines the efficacies and limitations of sensory nerve grafts and various other techniques used to induce functional neurological recovery, and how these might be improved to induce more extensive functional recovery. It also discusses preliminary data from the clinical application of a novel technique that restores neurological function across long nerve gaps, when repairs are performed at long times post-trauma, and in older patients, even under all three of these conditions. Thus, it appears that function can be restored under conditions where sensory nerve grafts are not effective.

Improvement in Impaired Social Cognition but Not Seizures by Everolimus in a Child with Tuberous Sclerosis-Associated Autism through Increased Serum Antioxidant Proteins and Oxidant/Antioxidant Status

We investigated the effect of the mammalian target of rapamycin (mTOR) inhibitor everolimus on tuberous sclerosis complex- (TSC-) associated autistic symptoms and focal seizures with impaired awareness in a female child with TSC. We further evaluated the relationship between improved autistic symptoms and seizures and increased the serum levels of the antioxidant proteins, ceruloplasmin (Cp) and transferrin (Tf), and oxidant-antioxidant status indicated by the oxidant marker oxidized low-density lipoprotein (ox-LDL) and the antioxidant marker total antioxidant power (TAP). Everolimus treatment improved impaired social cognition and autistic behaviors; however, seizure and epileptic activity persisted. Serum Cp and Tf levels gradually increased in response to improved autistic symptoms. Serum TAP levels gradually decreased from baseline to the lowest value at 16 weeks and then increased at 24 weeks, showing a trend toward decreased total score of the Aberrant Behavior Checklist. This study revealed that everolimus treatment improved impaired social cognition with increased serum levels of the copper mediator (Cp) and iron mediator (Tf) via homeostatic control of mTOR activity accompanied by overlap of the oxidant-antioxidant system. Everolimus had no effect on TSC-related epileptiform discharges, and thus, the autistic symptoms and epileptic activity may be two independent end results of a common central nervous system disorder including mTOR hyperactivity. This trial is registered with JMAS-IIA00258.

Tuberculous lymphadenitis is associated with altered levels of circulating angiogenic factors

BACKGROUND

Angiogenic factors are important in granuloma formation and serve as biomarkers in pulmonary tuberculosis (PTB). The relationship between these markers and tuberculous lymphadenitis (TBL) is not known.

OBJECTIVE AND DESIGN

To examine the association of vascular endothelial growth factor (VEGF) and angiopoietin (Ang) family molecules in TBL, we measured systemic levels of VEGF-A, C, D, R1 (VEGF-receptor 1), R2, R3, Ang-1, Ang-2 and TIE2 (tyrosine kinase with immunoglobulin-like and epidermal growth factor-like domains 2) levels in TBL, latent tuberculous infection (LTBI) and lymph node culture supernatants (VEGF-A, C and Ang-2) of the same TBL patients.

RESULTS

Circulating levels of VEGF-A and VEGF-C were significantly diminished, whereas VEGF-R2, R3, Ang-2 and TIE2 levels were significantly increased, in TBL. Likewise, VEGF-A, C and Ang-2 levels were significantly increased in lymph node supernatants compared with plasma in individuals with TBL. Receiver operating characteristic curve analysis showed that VEGF-C and VEGF-R2 markers clearly distinguished TBL from LTBI. Following treatment, VEGF-C and Ang-1 levels were significantly altered. No association was observed between angiogenic factors and culture grade or lymph node size, except for VEGF-A. VEGF-A was also significantly decreased in multiple lymph nodes compared with single lymph nodes.

CONCLUSIONS

Our data suggest that altered levels of circulating angiogenic factors in TBL might reflect underlying vasculo-endothelial dysfunction. Reversal of angiogenic markers after anti-tuberculosis treatment suggests that these angiogenic markers may serve as biomarkers of disease severity or response to treatment in TBL.

Increased soluble fms-like tyrosine kinase 1 after ischemia reperfusion contributes to adverse clinical outcomes following kidney transplantation

Renal ischemia reperfusion injury (IRI) adversely affects clinical outcomes following kidney transplantation. Understanding the cellular mechanisms and the changes in gene/protein expression following IRI may help to improve these outcomes. Serum soluble fms-like tyrosine kinase 1 (sFlt-1), a circulating antiangiogenic protein, is increased in the first week following kidney transplantation. We evaluated the casual relationship of elevated sFlt-1 levels with renal microvascular dysfunction following IRI in a longitudinal study of 93 kidney transplant recipients and in several animal models. Transplant recipients with higher sFlt-1 levels had higher odds of delayed graft function, graft rejection, impaired graft function, and death. In a subgroup of 25 participants who underwent kidney biopsy within 4 months of kidney transplantation, peritubular capillary area was lower in those with elevated serum sFtl-1 levels. The administration of recombinant sFlt-1 into rodents resulted in significant structural and functional changes of the renal microvasculature, including reduced peritubular capillary density and intracapillary blood volume, and lead to increased expression of inflammatory genes and increased fibrosis. In a murine model of IRI, the kidney was a site of sFlt-1 production, and systemic neutralization of sFlt-1 preserved peritubular capillary density and alleviated renal fibrosis. Our data indicate that high sFlt-1 levels after IRI play an important role in the pathogenesis of microvascular dysfunction, thereby contributing to adverse clinical outcomes following kidney transplantation.

Preoperative platelet counts and postoperative outcomes in cancer surgery: a multicenter, retrospective cohort study

Platelets play roles in malignancy, wound healing, and immunity. Nevertheless, their significance in postoperative outcomes is not established. This is a retrospective cohort study of 100,795 patients undergoing cancer surgery in 2010 and 2014 in >500 hospitals. Patients were stratified into five groups based on preoperative platelet counts. Multivariable logistic regression was used to determine the risk of 30-day mortality, morbidities, readmission, and prolonged hospitalization using the mid-normal group as a reference. We adjusted for demographic variables, comorbidities, and operation complexity. In the 2014 cohort, multivariable analysis showed that mortality was higher in patients with thrombocytopenia (OR 1.49, 95% CI [1.23-1.81]), high-normal platelets (OR 1.29, [1.06-1.55]), and thrombocytosis (OR 1.78, [1.45-2.19]). Composite postoperative morbidity followed a similar trend with thrombocytopenia (OR 1.34, [1.25-1.43]), high-normal counts (OR 1.41, [1.33-1.49]), and thrombocytosis (OR 2.20, [2.05-2.36]). Concordantly, the risks of prolonged hospitalization and 30-day readmission followed the same pattern. These results were validated in a large colon cancer cohort from the 2010 database. In conclusion, platelet count is a prognostic indicator in cancer surgeries. This could be related to the role of platelets in wound healing and immunity on one hand, and propagating malignancy on the other.

The Potential for Cancer Immunotherapy in Targeting Surgery-Induced Natural Killer Cell Dysfunction

Natural Killer (NK) cells are granular lymphocytes of the innate immune system that are able to recognize and kill tumor cells without undergoing clonal selection. Discovered over 40 years ago, they have since been recognized to possess both cytotoxic and cytokine-producing effector functions. Following trauma, NK cells are suppressed and their effector functions are impaired. This is especially important for cancer patients undergoing the removal of solid tumors, as surgery has shown to contribute to the development of metastasis and cancer recurrence postoperatively. We have recently shown that NK cells are critical mediators in the formation of metastasis after surgery. While research into the mechanism(s) responsible for NK cell dysfunction is ongoing, knowledge of these mechanisms will pave the way for perioperative therapeutics with the potential to improve cancer outcomes by reversing NK cell dysfunction. This review will discuss mechanisms of suppression in the postoperative environment, including hypercoagulability, suppressive soluble factors, the expansion of suppressive cell populations, and how this affects NK cell biology, including modulation of cell surface receptors, the potential for anergy, and immunosuppressive NK cell functions. This review will also outline potential immunotherapies to reverse postoperative NK dysfunction, with the goal of preventing surgery-induced metastasis.

Plasma Concentrations of Vascular Endothelial Growth Factor and Basic Fibroblast Growth Factor in Lymphoproliferative Disorders

Angiogenesis plays a major role in the development and progression of haematological malignancies. In our study we measured plasma concentrations of key angiogenic activators vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) using comercially available sandwich enzyme-linked immunosorbent assay (ELISA) in 37 patients with lymphoid malignancies and 20 healthy donors. We found a statistically significant increase in bFGF concentrations in patients with B-cell chronic lymphocytic leukemia (B-CLL, n=18) compared to the control group (median 118.8 vs. 9.3 pg/ml, p<0.001). However, we didn’t find any significant difference in VEGF concentrations between B-CLL patients and the control group. There was also no significant increase in bFGF or VEGF in patients with multiple myeloma (n=7) and non-Hodgkin’s lymphoma (n=12). Our pilot study shows that measurement of angiogenic activators in plasma is a feasible and reproducible method of angiogenesis assessment. Larger studies are needed for correlation between serum and plasma concentrations and detailed statistical evaluation including the impact on patients’ survival.

Elevated serum vascular endothelial growth factor and development of cardiac allograft vasculopathy in children

BACKGROUND

Cardiac allograft vasculopathy (CAV) is a leading cause of retransplantation and death in pediatric heart transplant recipients. Our aim was to evaluate the association between serum vascular endothelial growth factor-A (VEGF) and CAV development in the pediatric heart transplant population.

METHODS

In this retrospective study performed at a university hospital, VEGF concentrations were measured by enzyme-linked immunosorbent assay in banked serum from pediatric heart transplant recipients undergoing routine cardiac catheterization. In subjects with CAV (n = 29), samples were obtained at 2 time-points: before CAV diagnosis (pre-CAV) and at the time of initial CAV diagnosis (CAV). In subjects without CAV (no-CAV, n = 16), only 1 time-point was used. VEGF concentrations (n = 74) were assayed in duplicate.

RESULTS

Serum VEGF is elevated in pediatric heart transplant recipients before catheter-based diagnosis of CAV (no-CAV mean: 144.0 ± 89.05 pg/ml; pre-CAV mean: 316.2 ± 118.3 pg/ml; p = 0.0002). Receiver-operating characteristic curve analysis of pre-CAV VEGF levels demonstrated an area under the curve of 87.7% (p = 0.0002), with a VEGF level of 226.3 pg/ml predicting CAV development with 77.8% sensitivity and 91.7% specificity. VEGF is similarly elevated in subjects with angiographically diagnosed CAV and in those with normal angiography but intravascular ultrasound (IVUS) evidence of CAV.

CONCLUSIONS

The increase in serum VEGF before onset of detectable CAV is fundamental to its utility as a predictive biomarker and suggests further investigations of VEGF in the pathogenesis of CAV are warranted in the pediatric heart transplant population.

Short-term abstinence from alcohol and changes in cardiovascular risk factors, liver function tests and cancer-related growth factors: a prospective observational study

OBJECTIVE

To assess changes in metabolic risk factors and cancer-related growth factors associated with short-term abstinence from alcohol.

DESIGN

Prospective, observational study.

SETTING

Single tertiary centre.

PARTICIPANTS

Healthy subjects were recruited based on intention to: (1) abstain from alcohol for 1 month (abstinence group), or (2) continue to drink alcohol (control group). Inclusion criteria were baseline alcohol consumption >64 g/week (men) or >48 g/week (women). Exclusion criteria were known liver disease or alcohol dependence.

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcome was change in insulin resistance (homeostatic model assessment (HOMA) score). Secondary outcomes were changes in weight, blood pressure (BP), vascular endothelial growth factor (VEGF), epidermal growth factor (EGF) and liver function tests. Primary and secondary outcomes were adjusted for changes in diet, exercise and cigarette smoking.

RESULTS

The abstinence group comprised 94 participants (mean age 45.5 years, SD ±1.2) and the control group 47 participants (mean age 48.7 years, SD ±1.8). Baseline alcohol consumption in the abstinence group was 258.2 g/week, SD ±9.4, and in the control group 233.8 g, SD ±19.0. Significant reductions from baseline in the abstinence group (all p<0.001) were found in: HOMA score (-25.9%, IQR -48.6% to +0.3%), systolic BP (-6.6%, IQR -11.8% to 0.0%), diastolic BP (-6.3%, IQR -14.1% to +1.3%), weight (-1.5%, IQR -2.9% to -0.4%), VEGF (-41.8%, IQR -64.9% to -17.9%) and EGF (-73.9%, IQR -86.1% to -36.4%). None of these changes were associated with changes in diet, exercise or cigarette smoking. No significant changes from baseline in primary or secondary outcomes were noted in the control group.

CONCLUSION

These findings demonstrate that abstinence from alcohol in moderate-heavy drinkers improves insulin resistance, weight, BP and cancer-related growth factors. These data support an independent association of alcohol consumption with cancer risk, and suggest an increased risk of metabolic diseases such as type 2 diabetes and fatty liver disease.

Angiogenic Molecules in Hodgkin's Disease: Results from Sequential Serum Analysis

Increased angiogenic activity has been demonstrated in lymphoproliferative diseases including Hodgkin's disease. In the current study, the levels of circulating angiogenic molecules in 60 Hodgkin's patients were determined prior to and after treatment and correlated to disease stage and prognostic score. Hepatocyte growth factor (HGF), vascular endothelial growth factor (VEGF), interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) were increased in Hodgkin's patients in comparison to healthy controls (p<0.001). Angiogenin and angiopoietin-2 levels did not differ from controls. HGF, VEGF, TNF-α and angiogenin decreased significantly in Hodgkin's patients after standard treatment (p<0.001 for HGF, p<0.05 for VEGF, TNF-α and angiogenin). Furthermore, HGF and TNF-α increased with advancing stage of disease (p<0.05). HGF and VEGF correlated significantly with IL-6 (r=0.56, p<0.0005 and r=0.57, p<0.001 respectively). In conclusion, Hodgkin's disease displays an angiogenic activity as depicted by the increased serum levels of a number of angiogenic cytokines. HGF seems to be the prominent molecule in Hodgkin's disease, which may be used to monitor the disease status and the response to treatment.

Impact of continuous positive airway pressure on vascular endothelial growth factor in patients with obstructive sleep apnea: a meta-analysis

PURPOSE

Cumulative evidence supports the clear relationship of obstructive sleep apnea (OSA) with cardiovascular disease (CVD). And, adherence to continuous positive airway pressure (CPAP) treatment alleviates the risk of CVD in subjects with OSA. Vascular endothelial growth factor (VEGF), a potent angiogenic cytokine regulated by hypoxia-inducible factor, stimulates the progression of CVD. Thus, whether treatment with CPAP can actually decrease VEGF in patients with OSA remains inconclusive. The purpose of the present study was to quantitatively evaluate the impact of CPAP therapy on VEGF levels in OSA patients.

METHODS

We systematically searched Web of Science, Cochrane Library, PubMed, and Embase databases that examined the impact of CPAP on VEGF levels in OSA patients prior to May 1, 2017. Related searching terms were "sleep apnea, obstructive," "sleep disordered breathing," "continuous positive airway pressure," "positive airway pressure," and "vascular endothelial growth factor." We used standardized mean difference (SMD) to analyze the summary estimates for CPAP therapy.

RESULTS

Six studies involving 392 patients were eligible for the meta-analysis. Meta-analysis of the pooled effect showed that levels of VEGF were significantly decreased in patients with OSA before and after CPAP treatment (SMD = - 0.440, 95% confidence interval (CI) = - 0.684 to - 0.196, z = 3.53, p = 0.000). Further, results demonstrated that differences in age, body mass index, apnea-hypopnea index, CPAP therapy duration, sample size, and racial differences also affected CPAP efficacy.

CONCLUSIONS

Improved endothelial function measured by VEGF may be associated with CPAP therapy in OSA patients. The use of VEGF levels may be clinically important in evaluating CVD for OSA patients. Further large-scale, well-designed long-term interventional investigations are needed to clarify this issue.

Zinc regulates vascular endothelial cell activity through zinc-sensing receptor ZnR/GPR39

Zn2+ is an essential element for cell survival/growth, and its deficiency is linked to many disorders. Extracellular Zn2+ concentration changes participate in modulating fundamental cellular processes such as proliferation, secretion, ion transport, and cell signal transduction in a mechanism that is not well understood. Here, we hypothesize that the Zn2+-sensing receptor ZnR/G protein-coupled receptor 39 (GPR39), found in tissues where dynamic Zn2+ homeostasis takes place, enables extracellular Zn2+ to trigger intracellular signaling pathways regulating key cell functions in vascular cells. Thus, we investigated how extracellular Zn2+ regulates cell viability, proliferation, motility, angiogenesis, vascular tone, and inflammation through ZnR/GPR39 in endothelial cells. Knockdown of GPR39 through siRNA largely abolished Zn2+-triggered cellular activity changes, Ca2+ responses, as well as the downstream activation of Gαq-PLC pathways. Extracellular Zn2+ promoted vascular cell survival/growth through activation of cAMP and Akt as well as overexpressing of platelet-derived growth factor-α receptor and vascular endothelial growth factor A. It also enhanced cell adhesion and mobility, endothelial tubule formation, and cytoskeletal reorganization. Such effects from extracellular Zn2+ were not observed in GPR39-/- endothelial cells. Zn2+ also regulated inflammation-related key molecules such as heme oxygenase-1, selectin L, IL-10, and platelet endothelial cell adhesion molecule 1, as well as vascular tone-related prostaglandin I2 synthase and nitric oxide synthase-3. In sum, extracellular Zn2+ regulates endothelial cell activity in a ZnR/GPR39-dependent manner and through the downstream Gαq-PLC pathways. Thus, ZnR/GPR39 may be a therapeutic target for regulating endothelial activity.

[Systemic safety following intravitreal injections of anti-VEGF]

The goal of this manuscript is to assess data suggesting that intravitreal injection of anti-vascular endothelial growth factors (anti-VEGFs) could result in systemic adverse events (AEs). The class-specific systemic AEs should be similar to those encountered in cancer trials. The most frequent AE observed in oncology, hypertension and proteinuria, should thus be the most common expected in ophthalmology, but their severity should be lower because of the much lower doses of anti-VEGFs administered intravitreally. Such AEs have not been frequently reported in ophthalmology trials. In addition, pharmacokinetic and pharmacodynamic data describing systemic diffusion of anti-VEGFs should be interpreted with caution because of significant inconsistencies reported. Thus, safety data reported in ophthalmology trials and pharmacokinetic/pharmacodynamic data provide robust evidence that systemic events after intravitreal injection are very unlikely. Additional studies are needed to explore this issue further, as much remains to be understood about local and systemic side effects of anti-VEGFs.

Circulating Angiogenesis Regulators in Cancer Patients

Background/Aims

To date, numerous studies have demonstrated that several angiogenesis regulators circulate in the blood and may function as endocrine factors in cancer patients. This review aims to give a comprehensive insight into the possible clinical value of circulating angiogenesis regulators, mainly basic fibroblast growth factor (bFGF), vascular endothelial growth factor (VEGF), and hepatocyte growth factor (HGF), angiogenin, pleiotrophin, thrombospondin (TSP) and endostatin (ES) in cancer patients.

Methods

A computerized (MEDLINE) and a manual search based on the reference lists of the publications were performed to identify articles published on this topic.

Results

In a detailed literature search, approximately 100 publications were found up to the end of 1999. Circulating angiogenic factors such as bFGF, VEGF, HGF and angiogenin have been evaluated not only as diagnostic and/or prognostic factors but also as predictive factors in cancer patients. On the other hand, little is known about the clinical significance of negative regulators. Neither the source nor the mechanism of protein externalization has been clarified in detail.

Conclusions

Although there are no known factors with established clinical utility, circulating angiogenesis regulators may be useful in several situations. They could be used to determine the risk of developing cancer, to screen for early detection, to distinguish benign from malignant disease, and to distinguish between different types of malignancies. In patients with established malignancies such factors might be used to determine prognosis, to predict the response to therapy, and to monitor the clinical course. Further investigations are warranted to assess the specific utility of each factor.

Validation of Blood Collection Procedures for the Determination of Circulating Vascular Endothelial Growth Factor (VEGF) in Different Blood Compartments

Aims of the study.

Studies on circulating VEGF have reported mixed results, possibly due to a lack of standardization of the pre-analytical phase. The aim of our investigation was to standardize the sampling procedure for the determination of VEGF in different blood fractions.

Basic procedures.

We evaluated various clotting times for obtaining serum in 30 subjects, as well as different procedures for the preparation of plasma Edinburgh anticoagulant mixture (EDTA, PGE1, theophylline) and CTAD. VEGF was also assayed in lysed whole blood. In vitro platelet activation was monitored by measuring the levels of PF4. VEGF and PF4 were measured using commercially available enzyme-linked immunoassays.

Main findings.

Clotting time increased the release of VEGF, which reached a plateau between 2 and 4 hours. The percent increase of VEGF at 2 hours ranged from 118% to 4515% (median 327%) compared to samples centrifuged within 10 min from withdrawal. VEGF was not different and PF4 was very low or undetectable in Edinburgh plasma and CTAD plasma, while it was significantly higher in sodium citrate plasma. VEGF in CTAD plasma was not correlated with platelet count or leukocytes. Serum VEGF did not correlate with the leukocyte number, but it correlated significantly with the platelet count.

Principal conclusions.

The procedures for sample collection described above are highly standardized and easy to perform in a routine setting. We therefore suggest systematic evaluation of VEGF in CTAD plasma, in serum (clotting for 2 hours at room temperature) and in whole blood, until prospective controlled clinical studies will have clarified in which blood compartment(s) VEGF provides clinically relevant information.

The roles of cellular and molecular components of a hematoma at early stage of bone healing

Bone healing is a complex repair process that commences with the formation of a blood clot at the injured bone, termed hematoma. It has evidenced that a lack of a stable hematoma causes delayed bone healing or non-union. The hematoma at the injured bone constitutes the early healing microenvironment. It appears to dictate healing pathways that ends in a regenerative bone. However, the hematoma is often clinically removed from the damaged site. Conversely, blood-derived products have been used in bone tissue engineering for treating critical sized defects, including fibrin gels and platelet-rich plasma. A second generation of platelet concentrate that is based on leukocyte and fibrin content has also been developed and introduced in market. Conflicting effect of these products in bone repair are reported. We propose that the bone healing response becomes dysregulated if the blood response and subsequent formation and properties of a hematoma are altered. This review focuses on the central structural, cellular, and molecular components of a fracture hematoma, with a major emphasis on their roles in regulating bone healing mechanism, and their interactions with mesenchymal stem cells. New angles towards a better understanding of these factors and relevant mechanisms involved at the beginning of bone healing may help to clarify limited or adverse effects of blood-derived products on bone repair. We emphasize that the recreation of an early hematoma niche with critical compositions might emerge as a viable therapeutic strategy for enhanced skeletal tissue engineering.

POEMS SYNDROME: an Update

POEMS syndrome is a rare, chronic and disabling condition. The causes of this condition remain unknown; however, chronic overproduction of proinflammatory cytokines appears to be a major contributor. Early diagnosis is essential to start treatment before the clinical state of the patient becomes compromised. A complete evaluation of the disease at its onset is critical to the treatment decision. In localized disease, curative doses of radiation (50 Gy) is the recommended therapy. On the other hand, patients with disseminated disease should be given systemic therapy. Treatment-related morbidity can be minimized by an efficient induction therapy that modifies the cytokine status, improving clinical condition and control disease severity before mobilization and transplantation. Patients not suitable for hematopoietic stem cell transplantation (HSCT) are usually treated with alkylator-based therapy. Novel agents may also offer benefits to patients with a poor performance status or renal dysfunction, and induce transplantation eligibility. Given the biological characteristics of POEMS, immunomodulatory effects and the absence of neurotoxicity, lenalidomide appears to be an effective therapy for the treatment of POEMS, both as short induction therapy before PBSCT and in non-transplant eligible patients, as it showed high response rate and durable responses. At present, however, guidelines for the diagnosis and treatment of POEMS are not available and appear advocated.

Measuring myokines with cardiovascular functions: pre-analytical variables affecting the analytical output

In the last few years, a growing number of molecules have been associated to an endocrine function of the skeletal muscle. Circulating myokine levels, in turn, have been associated with several pathophysiological conditions including the cardiovascular ones. However, data from different studies are often not completely comparable or even discordant. This would be due, at least in part, to the whole set of situations related to the preparation of the patient prior to blood sampling, blood sampling procedure, processing and/or store. This entire process constitutes the pre-analytical phase. The importance of the pre-analytical phase is often not considered. However, in routine diagnostics, the 70% of the errors are in this phase. Moreover, errors during the pre-analytical phase are carried over in the analytical phase and affects the final output. In research, for example, when samples are collected over a long time and by different laboratories, a standardized procedure for sample collecting and the correct procedure for sample storage are acknowledged. In this review, we discuss the pre-analytical variables potentially affecting the measurement of myokines with cardiovascular functions.

Low-dose ranibizumab as primary treatment of posterior type I retinopathy of prematurity

OBJECTIVE

The aim of this study was to evaluate the visual and structural outcomes of eyes that received ranibizumab as treatment for retinopathy of prematurity (ROP).

METHODS

This was a retrospective case series of infants who received a 0.2 mg (0.02 mL) intravitreal injection of ranibizumab as the primary treatment for type 1 ROP. Outcome measures included regression or recurrence of ROP, complications of treatment, and assessment of visual acuity and refractive error.

RESULTS

Forty-two eyes of 21 infants (13 male) were included. Mean gestational age and birth weight were 24.6 ± 1.3 weeks and 613 ± 91 g, respectively. Mean age at injection was 37.4 ± 2.2 weeks postmenstrual age, and mean follow-up period was 10.1 ± 7 months. Active neovascularization regressed rapidly, and anatomical outcomes were favourable in all eyes. Twelve eyes of 6 infants received supplemental laser photocoagulation at a mean post-menstrual age (PMA) of 72.0 ± 27.3 weeks when vascularization had not advanced beyond zone II. Visual acuity was measurable in 28 of 42 eyes. Mean visual acuity was 0.94 ± 0.36 logMAR. Mean spherical equivalent was +1.00. There were no ocular or systemic complications in these patients and no cicatricial complications were observed with no progression to stage 4 or 5 disease.

CONCLUSIONS

A single intravitreal dose of 0.2 mg (0.02 mL) ranibizumab showed favourable anatomical and functional outcomes in eyes with type 1 ROP.

Is vascular endothelial growth factor a useful biomarker in giant cell arteritis?

Objectives

To assess the performance of circulating vascular endothelial growth factor (VEGF) levels as a tool for diagnosing giant cell arteritis (GCA) in a cohort of patients referred for assessment of suspected GCA.

Methods

We selected 298 patients recruited to the multicentre study Temporal Artery Biopsy versus Ultrasound in diagnosis of suspected GCA (TABUL). In a random subset of 26 biopsy-proven GCA cases and 26 controls, serum from weeks 0, 2 and 26 was analysed for VEGF concentration using ELISA. VEGF concentration at week 0 was used to generate a receiver-operating characteristic curve and thereby identify a cut-off for an abnormal result which was used to analyse the full patient cohort. Sections of paraffin-embedded temporal artery were stained by immunohistochemistry for VEGF.

Results

The mean (95% CI) VEGF concentration at week 0 was 873 pg/mL (631 to 1110) in 26 patients versus 476 pg/mL (328 to 625) in 26 controls (p=0.017). This difference was not observed at any other time point. The optimal cut-off of 713 pg/mL was applied to the whole patient cohort (n=298), yielding sensitivity of 32% and specificity of 85%. This was not improved by combination with any clinical parameters. When patients with biopsy-proven GCA were compared with controls, sensitivity was 58% and specificity remained 85%. Sections of biopsy from biopsy-positive GCA showed intense staining in the adventitia which was not seen in controls.

Conclusions

Serum VEGF concentration predicts biopsy positivity but is not useful for differentiating clinical cases of GCA from controls. Further studies into VEGF as a prognostic marker and therapeutic target are warranted.

Trial registration number

NCT00974883; Post-results.

No causal impact of serum vascular endothelial growth factor level on temporal changes in body mass index in Japanese male workers: a five-year longitudinal study

PURPOSE

It has been reported that adipocytes secrete vascular endothelial growth factor. Therefore, we conducted a 5-year longitudinal epidemiological study to further elucidate the association between vascular endothelial growth factor levels and temporal changes in body mass index.

METHODS

Our study subjects were Japanese male workers, who had regular health check-ups. Vascular endothelial growth factor levels were measured at baseline. To examine the association between vascular endothelial growth factor levels and overweight, we calculated the odds ratio using a multivariate logistic regression model. Moreover, linear mixed effect models were used to assess the association between vascular endothelial growth factor level and temporal changes in body mass index during the 5-year follow-up period.

RESULTS

Vascular endothelial growth factor levels were marginally higher in subjects with a body mass index greater than 25 kg/m² compared with in those with a body mass index less than 25 kg/m² (505.4 vs. 465.5 pg/mL, P = 0.1) and were weakly correlated with leptin levels (β: 0.05, P = 0.07). In multivariate logistic regression, subjects in the highest vascular endothelial growth factor quantile were significantly associated with an increased risk for overweight compared with those in the lowest quantile (odds ratio 1.65, 95 % confidential interval: 1.10-2.50). Moreover P for trend was significant (P for trend = 0.003). However, the linear mixed effect model revealed that vascular endothelial growth factor levels were not associated with changes in body mass index over a 5-year period (quantile 2, β: 0.06, P = 0.46; quantile 3, β: -0.06, P = 0.45; quantile 4, β: -0.10, P = 0.22; quantile 1 as reference).

CONCLUSIONS

Our results suggested that high vascular endothelial growth factor levels were significantly associated with overweight in Japanese males but high vascular endothelial growth factor levels did not necessarily cause obesity.

Sensitivity Limits for in vivo ELISA Measurements of Molecular Biomarker Concentrations

The extremely high sensitivity that has been suggested for magnetic particle imaging has its roots in the unique signal produced by the nanoparticles at the frequencies of the harmonics of the drive field. That sensitivity should be translatable to other methods that utilize magnetic nanoparticle probes, specifically towards magnetic nanoparticle spectroscopy that is used to measure molecular biomarker concentrations for an “in vivo ELISA” assay approach. In this paper, we translate the predicted sensitivity of magnetic particle imaging into a projected sensitivity limit for in vivo ELISA. The simplifying assumptions adopted are: 1) the limiting noise in the detection system is equivalent to the minimum detectable mass of nanoparticles; 2) the nanoparticle’s signal arising from Brownian relaxation is completely eliminated by the molecular binding event, which can be accomplished by binding the nanoparticle to something so massive that it can no longer physically rotate and is large enough that Neel relaxation is minimal. Given these assumptions, the equation for the minimum concentration of molecular biomarker we should be able to detect is obtained and the in vivo sensitivity is estimated to be in the attomolar to zeptomolar range. Spectrometer design and nonspecific binding are the technical limitations that need to be overcome to achieve the theoretical limit presented.

A functional bioassay to determine the activity of anti-VEGF antibody therapy in blood of patients with cancer

Background:

Only a small proportion of patients respond to anti-VEGF therapy, pressing the need for a reliable biomarker that can identify patients who will benefit. We studied the biological activity of anti-VEGF antibodies in patients' blood during anti-VEGF therapy by using the Ba/F3-VEGFR2 cell line, which is dependent on VEGF for its growth.

Methods:

Serum samples from 22 patients with cancer before and during treatment with bevacizumab were tested for their effect on proliferation of Ba/F3-VEGFR2 cells. Vascular endothelial growth factor as well as bevacizumab concentrations in serum samples from these patients were determined by enzyme linked immunosorbent assay (ELISA).

Results:

The hVEGF-driven cell proliferation was effectively blocked by bevacizumab (IC₅₀ 3.7 μg ml⁻¹; 95% CI 1.7–8.3 μg ml⁻¹). Cell proliferation was significantly reduced when patients' serum during treatment with bevacizumab was added (22–103% inhibition compared with pre-treatment). Although bevacizumab levels were not related, on-treatment serum VEGF levels were correlated with Ba/F3-VEGFR2 cell proliferation.

Conclusions:

We found that the neutralising effect of anti-VEGF antibody therapy on the biological activity of circulating VEGF can be accurately determined with a Ba/F3-VEGFR2 bioassay. The value of this bioassay to predict clinical benefit of anti-VEGF antibody therapy needs further clinical evaluation in a larger randomised cohort.

Vascular endothelial growth factor levels in patients with obstructive sleep apnea: a meta-analysis

Published articles regarding the blood levels of vascular endothelial growth factor (VEGF) in obstructive sleep apnea (OSA) patients are contradictory. The objective of this study was to explore whether VEGF levels is high or not in OSA subjects via quantitatively statistical analysis. The electronic databases of Pubmed, Web of Science, EMBASE were systematic searched. The VEGF levels and clinical characteristics of participants between OSA group and control group were extracted for analysis. Weighted mean difference (WMD) or standard mean difference (SMD) with 95 % confidence interval (CI) was calculated by fixed effects or random effects model. Appropriate statistical software was employed for data synthesis. Totaling 15 articles with 697 participants were included in this study. Pooled meta-analysis showed that blood VEGF concentrations were significantly higher in OSA patients than in control subjects (SMD 1.89, 95 % CI 0.92-2.87, p = 0.000). Subgroup analysis demonstrated that when compared with control group, OSA patients with age ≥50 years (SMD 2.54, 95 % CI 1.28-3.80, p = 0.000), apnea hypopnea index ≥30 events/h (SMD 2.47, 95 % CI 1.20-3.73, p = 0.000) had higher VEGF levels. Compared with control subjects, OSA patients had an elevated VEGF in serum (SMD 3.55, 95 % CI 1.82-5.28, p = 0.000) rather than in plasma. High blood VEGF concentrations were observed in OSA patients, particularly in the older and more serious patients.

Six Novel Loci Associated with Circulating VEGF Levels Identified by a Meta-analysis of Genome-Wide Association Studies

Vascular endothelial growth factor (VEGF) is an angiogenic and neurotrophic factor, secreted by endothelial cells, known to impact various physiological and disease processes from cancer to cardiovascular disease and to be pharmacologically modifiable. We sought to identify novel loci associated with circulating VEGF levels through a genome-wide association meta-analysis combining data from European-ancestry individuals and using a dense variant map from 1000 genomes imputation panel. Six discovery cohorts including 13,312 samples were analyzed, followed by in-silico and de-novo replication studies including an additional 2,800 individuals. A total of 10 genome-wide significant variants were identified at 7 loci. Four were novel loci (5q14.3, 10q21.3, 16q24.2 and 18q22.3) and the leading variants at these loci were rs114694170 (MEF2C, P = 6.79x10^-13), rs74506613 (JMJD1C, P = 1.17x10^-19), rs4782371 (ZFPM1, P = 1.59x10^-9) and rs2639990 (ZADH2, P = 1.72x10^-8), respectively. We also identified two new independent variants (rs34528081, VEGFA, P = 1.52x10^-18; rs7043199, VLDLR-AS1, P = 5.12x10^-14) at the 3 previously identified loci and strengthened the evidence for the four previously identified SNPs (rs6921438, LOC100132354, P = 7.39x10^-1467; rs1740073, C6orf223, P = 2.34x10^-17; rs6993770, ZFPM2, P = 2.44x10^-60; rs2375981, KCNV2, P = 1.48x10^-100). These variants collectively explained up to 52% of the VEGF phenotypic variance. We explored biological links between genes in the associated loci using Ingenuity Pathway Analysis that emphasized their roles in embryonic development and function. Gene set enrichment analysis identified the ERK5 pathway as enriched in genes containing VEGF associated variants. eQTL analysis showed, in three of the identified regions, variants acting as both cis and trans eQTLs for multiple genes. Most of these genes, as well as some of those in the associated loci, were involved in platelet biogenesis and functionality, suggesting the importance of this process in regulation of VEGF levels. This work also provided new insights into the involvement of genes implicated in various angiogenesis related pathologies in determining circulating VEGF levels. The understanding of the molecular mechanisms by which the identified genes affect circulating VEGF levels could be important in the development of novel VEGF-related therapies for such diseases.

Vascular Endothelial Growth Factor (VEGF) is a protein with a fundamental role in development of vascular system. The protein, produced by many types of cells, is released in the blood. High levels of VEGF have been observed in different pathological conditions especially in cancer, cardiovascular, and inflammatory diseases. Therefore, identifying the genetic factors influencing VEGF levels is important for predicting and treating such pathologies. The number of genetic variants associated with VEGF levels has been limited. To identify new loci, we have performed a Genome Wide Association Study meta-analysis on a sample of more than 16,000 individuals from 10 cohorts, using a high-density genetic map. This analysis revealed 10 variants associated with VEGF circulating levels, 6 of these being novel associations. The 10 variants cumulatively explain more than 50% of the variability of VEGF serum levels. Our analyses have identified genes known to be involved in angiogenesis related diseases and genes implicated in platelet metabolism, suggesting the importance of links between this process and VEGF regulation. Overall, these data have improved our understanding of the genetic variation underlying circulating VEGF levels. This in turn could guide our response to the challenge posed by various VEGF-related pathologies.