Phosphorylation of pericyte FAK-Y861 affects tumour cell apoptosis and tumour blood vessel regression

Focal adhesion kinase (FAK) is a non-receptor tyrosine kinase that is overexpressed in many cancer types and in vivo studies have shown that vascular endothelial cell FAK expression and FAK-phosphorylation at tyrosine (Y) 397, and subsequently FAK-Y861, are important in tumour angiogenesis. Pericytes also play a vital role in regulating tumour blood vessel stabilisation, but the specific involvement of pericyte FAK-Y397 and FAK-Y861 phosphorylation in tumour blood vessels is unknown. Using PdgfrβCre + ;FAKWT/WT, PdgfrβCre + ;FAKY397F/Y397F and PdgfrβCre + ;FAKY861F/Y861F mice, our data demonstrate that tumour growth, tumour blood vessel density, blood vessel perfusion and pericyte coverage were affected only in late stage tumours in PdgfrβCre + ;FAKY861F/Y861F but not PdgfrβCre + ;FAKY397F/Y397F mice. Further examination indicates a dual role for pericyte FAK-Y861 phosphorylation in the regulation of tumour vessel regression and also in the control of pericyte derived signals that influence apoptosis in cancer cells. Overall this study identifies the role of pericyte FAK-Y861 in the regulation of tumour vessel regression and tumour growth control and that non-phosphorylatable FAK-Y861F in pericytes reduces tumour growth and blood vessel density.

Quantitative Morphological Changes of the Choroidal Vasculature in Normal Aged and Diseased Human Donor eyes

Introduction: To analyze whether the choriocapillaries undergo degenerative changes with age and disease. Corrosion casts of choroidal vessels in human donors were investigated by scanning electron microscopy (SEM) to understand the vasculature changes with age.Method: The patterns of blood vessels, vortex veins, ciliary arteries placements, capillaries placement from centre to periphery in different quadrants and regions of choroid were evaluated in twenty donor normal tissues aged from 20-90 years. Nine donors had diabetic donor tissues were evaluated in which different quadrants with laser marks and loss of blood vessels were quantified along with, six donors with signs of age-related macular degeneration were evaluated using a light stereoscopic dissection microscope. Six human donors were investigated by SEM of which two tissues were normal, two had diabetic retinopathy and two presented with age related macular degeneration changes. Result: The quantitative evaluation revealed that in normal to diseased there is a decrease of the blood vessel density in comparison to the total area of the choroid. There was also slight decrease from to centre to periphery in the % area of the blood vessel placement. Morphological identification noted was a greater number of vortex veins were noted in inferior end than the superior end. There was prominent loss of blood vessel bed was noted beneath the lasered areas in diabetic retinopathy tissues. Conclusion: Loss of % area of blood vessel density was directly correlating with the progression of age and in diabetic retinopathy diseased tissues we noted prominent loss of blood vessels underneath the laser treated areas. In age related macular degeneration, loss of blood vessels was prominent in different quadrants with age too.

In Vivo Tumor Vascular Imaging with Light Emitting Diode-Based Photoacoustic Imaging System

Photoacoustic (PA) imaging has shown tremendous promise for imaging tumor vasculature and its function at deeper penetration depths without the use of exogenous contrast agents. Traditional PA imaging systems employ expensive and bulky class IV lasers with low pulse repetition rate, due to which its availability for preclinical cancer research is hampered. In this study, we evaluated the capability of a Light-Emitting Diode (LED)-based PA and ultrasound (US) imaging system for monitoring heterogeneous microvasculature in tumors (up to 10 mm in depth) and quantitatively compared the PA images with gold standard histology images. We used a combination of a 7 MHz linear array US transducer and 850 nm excitation wavelength LED arrays to image blood vessels in a subcutaneous tumor model. After imaging, the tumors were sectioned and stained for endothelial cells to correlate with PA images across similar cross-sections. Analysis of 30 regions of interest in tumors from different mice showed a statistically significant R-value of 0.84 where the areas with high blood vessel density had high PA response while low blood vessel density regions had low PA response. Our results confirm that LED-based PA and US imaging can provide 2D and 3D images of tumor vasculature and the potential it has as a valuable tool for preclinical cancer research.

Testicular immune cells and vasculature in Klinefelter syndrome from childhood up to adulthood

STUDY QUESTION Is the distribution of immune cells and the testicular vasculature altered in testicular biopsies from patients with Klinefelter syndrome (KS)? SUMMARY ANSWER Increased numbers of macrophages and mast cells, an increased expression of decorin and an increased blood vessel density were found in KS samples compared to controls. WHAT IS KNOWN ALREADY Most KS patients are infertile due to an early germ cell loss. From puberty onwards, testicular fibrosis can be detected. How this fibrotic process is initiated remains unknown. STUDY DESIGN, SIZE, DURATION In this study, the number of macrophages, mast cells and their secretory products were evaluated in KS, Sertoli cell only (SCO) and control patient samples. The association between immune cell numbers and level of fibrosis in KS tissue was examined. In addition, the vascularization within these testicular tissue biopsies was studied. For immunohistochemical evaluation, KS patients at different stages of testicular development were included: prepubertal (aged 4–7 years; n = 4), peripubertal (aged 11–17 years; n = 21) and adult (aged >18 years; n = 37) patients. In addition, testicular tissue biopsies of adult SCO (n = 33) and control samples for the three KS age groups (prepubertal n = 9; peripubertal n = 5; adult n = 25) were analysed. Gene expression analysis was performed on adult testicular tissue from KS (n = 5), SCO (n = 5) and control (n = 5) patients. PARTICIPANTS/MATERIALS, SETTING, METHODS Adult (>18 years) KS, SCO and control testicular tissue biopsies were obtained during a testicular sperm extraction procedure. KS peripubertal (11–18 years), prepubertal (<11 years) and age-matched control biopsies were obtained from the biobank of the university hospital. Immunohistochemistry was used to determine the tubular structure (H/PAS), the number of spermatogonia (MAGE-A4), macrophages (CD68) and mast cells (tryptase) and the blood vessel density (Von Willebrand factor). In addition, quantitative real-time polymerase chain reaction was used to determine the expression of secretory products of macrophages and mast cells (tryptase, tumour necrosis factor alpha and decorin). MAIN RESULTS AND THE ROLE OF CHANCE A significant increase in the number of macrophages (P < 0.0001) and mast cells (P = 0.0008) was found in the peritubular compartment of testes of adult KS patients compared to control samples. However, no association between the number of immune cells and the degree of fibrosis was observed. In adult SCO samples, a significant increase was seen for peritubular macrophage (P < 0.0001) and mast cell (P < 0.0001) numbers compared to control samples. In the interstitial compartment, a significant increase in mast cell number was found in adult SCO samples compared to KS (P < 0.0001) and control (P < 0.0001) tissue. A significant difference (P = 0.0431) in decorin expression could be detected in adult KS compared to control patients. Decorin expression was mostly seen in the walls of the seminiferous tubules. When comparing the vascularization between KS patients and age-matched controls, a significant increase (P = 0.0081) in blood vessel density could be observed only in prepubertal KS testicular tissue. LARGE SCALE DATA N/A. LIMITATIONS, REASONS FOR CAUTION As controls for this study, testicular tissue biopsies of men who underwent a vasectomy reversal or orchiectomy were used, but these men may not represent fertile controls. In addition, a high variability in immune cell numbers, secretory products expression and number of blood vessels could be observed amongst all patient samples. WIDER IMPLICATIONS OF THE FINDINGS Increased numbers of macrophages and mast cells have previously been described in non-KS infertile men. Our results show that these increased numbers can also be detected in KS testicular tissue. However, no association between the number of macrophages or mast cells and the degree of fibrosis in KS samples could be detected. Decorin has previously been described in relation to fibrosis, but it has not yet been associated with testicular fibrosis in KS. Our results suggest a role for this proteoglycan in the fibrotic process since an increased expression was observed in adult KS tissue compared to controls. Impaired vascularization in KS men was suggested to be responsible for the KS-related disturbed hormone levels. Our results show a significant difference in blood vessel density, especially for the smallest blood vessels, between prepubertal KS samples and age-matched controls. This is the first study to report differences between KS and control testicular tissue at prepubertal age. STUDY FUNDING/COMPETING INTEREST(S) The project was funded by grants from the Vrije Universiteit Brussel (E.G.) and the scientific Fund Willy Gepts from the UZ Brussel (D.V.S.). D.V.S. is a post-doctoral fellow of the Fonds voor Wetenschappelijk Onderzoek (FWO; 12M2819N). No conflict of interest is declared for this research project.