Localized expression of angiopoietin 1 and 2 may explain unique characteristics of the rat testicular microvasculature

Exogenous gonadotropin-releasing hormone counteracts the adverse effect of scrotal insulation on testicular functions in bucks

This study determined the effects of scrotal insulation on testicular functions in bucks and evaluated the impact of exogenous gonadotropin-releasing hormone (GnRH) administration before scrotal insulation on sperm production and testicular vascular dynamics. Twelve bucks were randomly divided into three groups: scrotal-insulated animals without GnRH treatment (INS), scrotal-insulated animals treated previously with GnRH (GnRH + INS), and animals without insulation as controls (CON). Doppler ultrasonography was used to evaluate testicular vascular changes, and semen samples were collected to assess seminal parameters. Testicular samples were collected from slaughtered bucks at the end of the experiment for histological investigations and immunohistochemical analysis for caspase 3 (apoptotic marker), and a vascular endothelial growth factor (VEGF; hypoxic marker) evaluation. Sperm motility drastically decreased (33%) in the INS group on day 8 compared with those in the GnRH + INS and CON groups (58% and 85%, respectively). Testicular blood flow significantly decreased for 3 and 2 weeks in the INS and GnRH + INS groups, respectively. The pulsatility index (PI) reached pretreatment values at 5 and 4 weeks after insulation in the INS and GnRH + INS groups, respectively. The resistance index (RI) values increased in both insulated groups for the first 2 weeks and decreased to control values 4 weeks after insulation. However, the maximum velocity (VP) started to increase reaching pretreatment values by the 5th and 3rd weeks after insulation in the INS and GnRH + INS groups, respectively. Histological investigations showed a marked reduction in lipid inclusions in Sertoli cells in the GnRH + INS group compared with those in the INS group. The distributions of both caspase 3 and VEGF decreased in the GnRH + INS group compared with those in the INS group. This study showed that the administration of a single dose of GnRH delayed the negative effects of scrotal insulation on different seminal traits and revealed the pivotal role of GnRH in compensating testicular insulation in bucks.

Systemic analysis of gene expression profiles in porcine granulosa cells during aging

Current studies have revealed that aging is a negative factor that suppresses granulosa cell functions and causes low fertility in women. However, the difference in gene expression between normal and aging granulosa cells remains undefined. Therefore, the aim of this study was to investigate the gene expression profiles of granulosa cells during aging. Granulosa cells from young healthy porcine ovaries were aged in vitro by prolonging the culture time (for 48h). First, the extracellular ultrastructure was observed by scanning electron microscopy followed by RNA-seq and KEGG pathway analysis. The results showed that the extracellular ultrastructure was significantly altered by aging; cell membranes were rough, and cavitations were found. Moreover, the formations of filopodia were greatly reduced. RNA-seq data revealed that 3411 genes were differentially expressed during aging, of which 2193 genes were up-regulated and 1218 genes were down-regulated. KEGG pathway analysis revealed that 25 pathways including pathway in cancer, PI3K-Akt signaling pathway, focal adhesion, proteoglycans in cancer, and cAMP signaling pathway were the most changed. Moreover, several high differentially expressed genes (CEBPB, CXCL12, ANGPT2, IGFBP3, and BBOX1) were identified in aging granulosa cells, The expressions of these genes and genes associated with extracellular matrix remodeling associated genes (TIMP3, MMP2, MMP3, and CTGF), energy metabolism associated genes (SLC2A1, PPARγ) and steroidogenesis associated genes (StAR, CYP11A1 and LHCGR) were confirmed by quantitative PCR. This study identifies the differently changed pathways and their related genes, contributes to the understanding of aging in granulosa cells, and provides an important foundation for further studies.

Endocrine Gland-Derived Vascular Endothelial Growth Factor/Prokineticin-1 in Cancer Development and Tumor Angiogenesis

A lot of data suggests endocrine gland-derived vascular endothelial growth factor (EG-VEGF) to be restricted to endocrine glands and to some endocrine-dependent organs. Many evidences show that EG-VEGF stimulates angiogenesis and cell proliferation, although it is not a member of the VEGF family. At the time, a lot of data regarding the role of this growth factor in normal development are available. However, controversial results have been published in the case of pathological conditions and particularly in malignant tumors. Thus, our present paper has been focused on the role of EG-VEGF in normal tissues and various malignant tumors and their angiogenic processes.

Urinary angiopoietin-2 is associated with albuminuria in patients with type 2 diabetes mellitus

Aims. To evaluate the levels of angiopoietin-1 (Ang-1), Ang-2, and vascular endothelial growth factor (VEGF) in serum and urine, and their association with albuminuria in patients with type 2 diabetes mellitus. Methods. In 113 type 2 diabetic patients with normoalbuminuria, microalbuminuria, and macroalbuminuria and 30 healthy controls, the levels of Ang-1, Ang-2, and VEGF in serum and urine were measured by enzyme-linked immunosorbent assay (ELISA). Results. Urinary and serum levels of Ang-2 were significantly higher in diabetic patients with normoalbuminuria than in healthy controls. Increased urinary Ang-2 level was positively associated with the degree of albuminuria. Urinary Ang-1 levels were significantly higher in normoalbuminuria patients and lower in macroalbuminuria patients than in controls. The levels of urinary VEGF increased in the albuminuria subgroup, though serum levels of Ang-1 and VEGF did not change. Urinary Ang-2 levels were correlated positively with albuminuria and negatively with glomerular filtration rate (GFR). Stepwise multiple regression analysis identified albuminuria (P < 0.001) and GFR (P = 0.001) as significant predictors of urinary Ang-2. Conclusions. Our data suggest that urinary Ang-2 is stepwise increased with renal damage in patients with type 2 diabetes mellitus and is associated with albuminuria.

Serum angiopoietin-2 and β-hCG as predictors of prolonged uterine bleeding after medical abortion in the first trimester

OBJECTIVE

The combination of mifepristone and misoprostol is an established method for induction of early first trimester abortion, but there is no consensus about the best evaluation of treatment outcome. We evaluate serum Angiopoietin-2 (Ang-2) and β human chorionic gonadotropin (β-hCG) in women who had undergone a medical abortion as markers of prolonged uterine bleeding (PUB).

METHODS

Prospective trial involving 2843 women attending an gynecology outpatient clinic who following a medical abortion with mifepristone and misoprostol, the study cohort was divided into women with duration of uterine bleeding >14 days (PUB) and women with duration of uterine bleeding ≤14 days (normal uterine bleeding, NUB). Serum determinations of Ang-2 levels by ELISA and β-hCG levels by electrochemiluminiscence immunoassay. Receiver Operating Characteristics (ROC) analyses were calculated and plotted for the diagnostic accuracy of serum β-hCG and Ang-2 concentration to discriminate PUB and NUB.

RESULTS

Baseline characteristics for both groups were similar, Only duration of bleeding showed a significant difference between the PUB group and NUB group. Ang-2 serum levels moderately correlated with serum β-hCG levels with statistically significant correlation coefficients of 0.536. Serum β-hCG and Ang-2 levels on day 7 and on day 14 after medical abortion were signifcantly higher in PUB group than in NUB group. Plotted as ROC curves, β-hCG area under curve (AUC) was 0.65 (95% CI, 0.53-0.76) on day 7, rising to AUC = 0.83 (95% CI, 0.75-0.92) on day 14. Using Ang-2 on day 7 and day 14 as predictive parameter resulted in an analogous AUC (AUC = 0.61 on day 7, AUC = 0.78 on day 14).

CONCLUSIONS

Both parameters are clinically useful as a diagnostic test in predicting PUB after medical abortion, and can be helpful in uncertain clinical situations, but should be considered as supplementary to a general clinical evaluation.

Exhaled breath temperature and exercise-induced bronchoconstriction in asthmatic children

It has been hypothesized that exhaled breath temperature (EBT) is related to the degree of airway inflammation/remodeling in asthma. The purpose of this study was to evaluate the relationship between the level of airway response to exercise and EBT in a group of controlled or partly controlled asthmatic children. Fifty asthmatic children underwent measurements of EBT before and after a standardized exercise test. EBT was 32.92 ± 1.13 and 33.35 ± 0.95°C before and after exercise, respectively (P < 0.001). The % decrease in FEV(1) was significantly correlated with the increase in EBT (r = 0.44, P = 0.0013), being r = 0.49 (P < 0.005) in the children who were not receiving regular inhaled corticosteroids (ICS) and 0.37 (n.s.) in those who were. This study further supports the hypothesis that EBT can be considered a potential composite tool for monitoring asthma.

Molecular correlates of experimental cerebral malaria detectable in whole blood

Cerebral malaria (CM) is a primary cause of deaths caused by Plasmodium falciparum in young children in sub-Saharan Africa. Laboratory tests based on early detection of host biomarkers in patient blood would help in the prognosis and differential diagnosis of CM. Using the Plasmodium berghei ANKA murine model of experimental cerebral malaria (ECM), we have identified over 300 putative diagnostic biomarkers of ECM in the circulation by comparing the whole-blood transcriptional profiles of resistant mice (BALB/c) to those of two susceptible strains (C57BL/6 and CBA/CaJ). Our results suggest that the transcriptional profile of whole blood captures the molecular and immunological events associated with the pathogenesis of disease. We find that during ECM, erythropoiesis is dysfunctional, thrombocytopenia is evident, and glycosylation of cell surface components may be modified. Furthermore, analysis of immunity-related genes suggests that slightly distinct mechanisms of immunopathogenesis may operate in susceptible C57BL/6 and CBA/CaJ mice. Furthermore, our data set has allowed us to create a molecular signature of ECM composed of a subset of circulatory markers. Complement component C1q, β-chain, nonspecific cytotoxic cell receptor protein 1, prostate stem cell antigen, DnaJC, member 15, glutathione S-transferase omega-1, and thymidine kinase 1 were overexpressed in blood during the symptomatic phase of ECM, as measured by quantitative real-time PCR analysis. These studies provide the first host transcriptome database that is uniquely altered during the pathogenesis of ECM in blood. A subset of these mediators of ECM warrant validation in P. falciparum-infected young African children as diagnostic markers of CM.

Serum human chorionic gonadotropin is associated with angiogenesis in germ cell testicular tumors

BACKGROUND

Germ cell testicular tumors have survival rate that diminishes with high tumor marker levels, such as human chorionic gonadotropin (hCG). hCG may regulate vascular neoformation through vascular endothelial growth factor (VEGF). Our purpose was to determine the relationship between hCG serum levels, angiogenesis, and VEGF expression in germ cell testicular tumors.

METHODS

We conducted a retrospective study of 101 patients. Serum levels of hCG, alpha-fetoprotein (AFP), and lactate dehydrogenase were measured prior to surgery. Vascular density (VD) and VEGF tissue expression were determined by immunohistochemistry and underwent double-blind analysis.

RESULTS

Histologically, 46% were seminomas and 54%, non-seminomas. Median follow-up was 43 +/- 27 months. Relapse was present in 7.5% and mortality in 11.5%. Factors associated with high VD included non-seminoma type (p = 0.016), AFP > or = 14.7 ng/mL (p = 0.0001), and hCG > or = 25 mIU/mL (p = 0.0001). In multivariate analysis, the only significant VD-associated factor was hCG level (p = 0.04). When hCG levels were stratified, concentrations > or = 25 mIU/mL were related with increased neovascularization (p < 0.0001). VEGF expression was not associated with VD or hCG serum levels.

CONCLUSION

This is the first study that relates increased serum hCG levels with vascularization in testicular germ cell tumors. Hence, its expression might play a role in tumor angiogenesis, independent of VEGF expression, and may explain its association with poor prognosis. hCG might represent a molecular target for therapy.

Increased levels of angiopoietin-2 in induced sputum from smoking asthmatic patients

BACKGROUND

Active cigarette smoking has detrimental effects on asthma morbidity and severity. Angiopoietin-1 has been shown to protect the microvessels against plasma leakage, whereas angiopoietin-2 enhances vascular permeability and subsequently induces airway mucosal oedema. Therefore, it is recently thought that angiopoietin-2 may contribute to the pathophysiology of asthma.

OBJECTIVE

To determine whether angiopoietin-2 levels in the airways are associated with clinical profiles in smoking asthmatics.

METHODS

We measured angiopoietin-1 and -2 levels in induced sputum in 35 normal controls (18 non-smokers and 17 smokers) and 49 asthmatics (24 non-smokers and 25 smokers) before and after inhaled beclomethasone dipropionate (BDP: 800 microg/day) therapy for 12 weeks.

RESULTS

Angiopoietin-1 and -2 levels in induced sputum were significantly higher in asthmatics than in normal controls. Moreover, angiopoietin-2 levels were significantly higher in smoking asthmatics than in non-smoking asthmatics (P=0.0001). The airway vascular permeability index was also higher in smoking asthmatics than in non-smoking asthmatics. Moreover, the angiopoietin-2 level was positively correlated with the airway vascular permeability index (non-smoking asthmatics: r=0.87, P<0.001, smoking asthmatics: r=0.64, P=0.002). After BDP therapy, angiopoietin-1 levels were significantly decreased in non-smoking asthmatics, smoking-cessation asthmatics, and active-smoking asthmatics. In contrast, angiopoietin-2 levels did not differ from before to after BDP therapy in non-smoking asthmatics and active-smoking asthmatics. However, its levels were significantly decreased from before to after BDP therapy in smoking-cessation asthmatics (P=0.002). Although forced expiratory volume in 1 s (FEV(1))/forced vital capacity (FVC) before BDP therapy was comparable in all subgroups, this parameter after BDP therapy was significantly lower in active-smoking asthmatics than in non-smoking and smoking-cessation asthmatics. Moreover, the reduction in angiopoietin-2 levels after BDP therapy in smoking-cessation asthmatics was significantly correlated with an improvement in FEV(1)/FVC.

CONCLUSION

Angiopoietin-2 levels were elevated in the airways of smoking asthmatics, and its levels were associated with impaired airway responses.

Regulation of placental villous angiopoietin-1 and -2 expression by estrogen during baboon pregnancy

We recently showed an increase in vascular endothelial growth factor (VEGF), decrease in angiopoietin-1 (Ang-1) and unaltered Ang-2 expression by the villous placenta with advancing baboon pregnancy. Moreover, placental VEGF expression was increased by estrogen in early pregnancy. In the present study, we determined whether placental Ang-1 and Ang-2 are regulated by estrogen. Ang-1 and Ang-2 mRNA and protein were determined by RT-PCR and immunocytochemistry in the placenta of baboons on Day 60 of gestation (term is 184 days) after administration of estrogen precursor androstenedione on Days 25-59 or on Day 54 after acute estradiol administration. Chronic androstenedione treatment increased serum estradiol levels three-fold (P < 0.001) and decreased (P < 0.05) villous cytotrophoblast Ang-1 mRNA to a level (0.36 +/- 0.08 relative to 18S rRNA) that was one-third of that in untreated animals (0.98 +/- 0.26). Within 2 hr of estradiol administration, cytotrophoblast Ang-1 mRNA was decreased to a level (0.24 +/- 0.05) one-fifth (P < 0.05) of that in untreated animals (1.14 +/- 0.23). However, Ang-2 mRNA levels were unaltered. Ang-1, Ang-2 and estrogen receptors alpha and beta protein were localized within villous cytotrophoblasts providing a mechanism for estrogen action at this site. In summary, estrogen increased VEGF, decreased Ang-1, and had no effect on Ang-2 expression within placental cytotrophoblasts during early baboon pregnancy. We propose that the estrogen-dependent differential regulation of these angioregulatory factors underpins the unique pattern of neovascularization established within the villous placenta during primate pregnancy.

Angiopoietin-2 as a contributing factor of exercise-induced bronchoconstriction in asthmatic patients receiving inhaled corticosteroid therapy

BACKGROUND

Airway microcirculation has the potential to contribute to the pathogenesis of exercise-induced bronchoconstriction (EIB) in asthma. Recently, angiopoietin-1 has been found to stabilize microvessels and make them leak resistant, whereas angiopoietin-2 is an antagonist of angiopoietin-1 and enhances microvascular permeability.

OBJECTIVE

We sought to examine the roles of angiopoietin-2 in EIB in asthmatic patients with inhaled corticosteroid therapy.

METHODS

Levels of angiopoietin-1 and angiopoietin-2 in induced sputum were examined in 32 asthmatic patients who were receiving inhaled corticosteroid therapy for more than 6 months at the entry of this study and 14 healthy control subjects. All asthmatic patients performed an exercise test.

RESULTS

The degree of eosinophilic airway inflammation did not differ significantly between asthmatic patients and healthy control subjects. Angiopoietin-1 levels were also similar in the 2 groups (asthmatic patients: median, 6.0 ng/mL [range, 2.0-10.7 ng/mL]; healthy control subjects: median, 4.2 ng/mL [range, 1.5-10.7 ng/mL]). In contrast, angiopoietin-2 levels were significantly higher in asthmatic patients than in healthy control subjects (asthmatic patients: median, 0.74 ng/mL [range, 0.3-1.2 ng/mL]; healthy control subjects: median, 0.26 ng/mL [range, 0.05-0.47 ng/mL]; P < .001). There was no significant correlation between angiopoietin-1 levels and the severity of EIB in asthmatic patients. However, angiopoietin-2 levels were significantly correlated with the severity of EIB and airway microvascular permeability index.

CONCLUSION

Angiopoietin-2 levels were increased in the airways of asthmatic patients with inhaled corticosteroid therapy, and its levels were associated with the severity of EIB.

Roles of angiopoietin-1 and angiopoietin-2 on airway microvascular permeability in asthmatic patients

BACKGROUND

Vascular endothelial growth factor (VEGF) increases microvascular permeability. Recently, considerable attention has been devoted to the physiologic roles of angiopoietin-1 and angiopoietin-2 as regulatory factors of VEGF. This study was designed to examine the roles of angiopoietin-1 and angiopoietin-2 in controlling airway microvascular permeability in asthma.

METHODS

Levels of these angiogenic factors and airway vascular permeability index were examined in 30 asthmatics and 12 control subjects. After 2-week run-in period, all asthmatics were randomly assigned to receive fluticasone propionate (400 mug/d) or montelukast (10 mg) for 12 weeks.

RESULTS

VEGF, angiopoietin-1, and angiopoietin-2 levels in induced sputum were significantly higher in asthmatics than in control subjects. We found an inverse correlation between angiopoietin-1 level and vascular permeability index in asthmatics, while there was a positive correlation between angiopoietin-2 level and that index. VEGF and angiopoietin-1 levels were significantly decreased after fluticasone therapy, while VEGF and angiopoietin-2 levels were significantly decreased after montelukast therapy. Although VEGF levels after treatment were different between two groups, vascular permeability index in the montelukast group was the same level as that in the fluticasone group. Moreover, improvement in vascular permeability index after fluticasone therapy was inversely correlated with decrease in angiopoietin-1 level, while that after montelukast therapy was positively correlated with decrease in angiopoietin-2 level.

CONCLUSIONS

Angiopoietin-1 and angiopoietin-2 play complementary and coordinated roles in regulating microvascular permeability stimulated by VEGF in asthma. Combination of corticosteroids with leukotriene antagonists might effectively improve plasma leakage and provide a new strategy in treating bronchial asthma.

The gonadotropins: tissue-specific angiogenic factors?

The gonadotropins, whose members are human chorionic gonadotropin (hCG), lutenizing hormone (LH) and follicle-stimulating hormone (FSH) are a well characterized hormone family known to regulate reproductive functions in both females and males. Recent studies indicate that they can modulate the vascular system of reproductive organs. It was shown that gonadotropins not only influence the expression of vascular endothelial growth factor (VEGF) and both its receptors VEGFR-1 and -2, but also modulate other ubiquitously expressed angiogenic factors like the angiopoietins and their receptor Tie-2, basic fibroblast growth factor or placental-derived growth factor. Some recent data indicates a possible direct action of gonadotropins on endothelial cells. Thus, the gonadotropins act as tissue-specific angiogenic factors providing an optimal vascular supply during the menstrual cycle and early pregnancy in the female reproductive tract as well as in testis. In pathological conditions (e.g. preeclampsia, intrauterine growth restriction, ovarian hyperstimulation or endometriosis), these tightly regulated interactions between the gonadotropins and the ubiquitous angiogenic factors appear to be disturbed. The intent of this short manuscript is to review the current knowledge of the regulatory role of the gonadotropins in vasculo- and angiogenesis. We also review angiogenic actions of thyroid-stimulating hormone (TSH), a glycoprotein closely related to gonadotropins, which display strong gonodal actions.

A potential pathological role of angiopoietins expression in glomeruli during progressive glomerulisclerosis related to podocyte injury

A potential pathological role of angiopoietins (Ang) in glomeruli following podocyte injury-induced progressive glomerulosclerosis was explored. Eighty male Wistar rats were randomly allocated into sham operation group (Sham, n = 25), Uninephrectomy group (UPHT, n = 25) and Uninephrectomy+Daunorubicin group (DRB, n = 30). In DRB group, daunorubicin (5 mg/kg) was injected via tail vein on the 7th and 14th day after uninephrectomy. At week 1, 2, 4, 6 and 8 respectively following establishment of the animal model, 5 rats in Sham group and UPHT group, and 6 in DRB group were taken respectively for determining 24-h urinary protein excretion rate (24hUPER), blood urea nitrogen (BUN) and serum creatinine (Scr). The sections of kidneys were examined by an electric microscope, PAS staining, immunohistochemical staining and in situ hybridization histochemistry. The results showed that 24hUPER, BUN and Scr in DRB group were more than those in Sham group and UPHT group at the same time points, and there was a trend towards an increase on level of GSI in DRB group from week 2 to week 8. Electric microscopy revealed that podocyte injury presented in DRB group. The expression of Ang1 mRNA and protein in glomeruli of DRB group was decreased, while the expression of Ang2 protein in glomeruli of DRB group increased. Meanwhile, the expression of Ang1 mRNA had a negative correlation with the expression of Ang2 mRNA, and the expression of Ang1 protein had a positive correlation with the expression of Ang1 mRNA, and had a negative correlation with 24hUPER, BUN, Scr, glomerular sclerotic index (GSI), the expression of Ang2 protein and CoIV protein. The expression of Ang2 protein had a positive correlation with the expression of Ang2 mRNA, and had a positive correlation with 24hUPER, BUN, Scr, GSI, the expression of CoIV protein. It was concluded that podocyte injury might lead to an alteration in the expression of Ang1 and Ang2 within glomeruli. Ang2 may get rid of inhibition from Ang1 for downregulation of the Ang1 expression, which facilitate upregulation of the Ang2 expression in glomeruli to promote progressive glomerulosclerosis in the rats.

Changes in angiopoietin expression in glomeruli involved in glomerulosclerosis in rats with daunorubicin-induced nephrosis

AIM

To study the potential pathological role of endogenous angiopoietins in daunorubicin-induced progressive glomerulosclerosis in rats.

METHODS

Seventy male Wistar rats were allocated randomly into a daunorubicin group (DRB; n=40) or a control group (n=30). The rats in the DRB group were injected with DRB (15 mg/kg), in their tails. Subsequently, at intervals of 1, 2, 4, 6, 8, and 12 weeks, 5 male Wistar rats in each group were chosen randomly for 24 h urinary protein quantitative measurements (24 h UPQM), and determination of plasma tumor necrosis factor alpha (TNF-alpha), angiopoietin-1 (Ang1), and angiopoietin-2 (Ang2) levels. Kidney sections were examined by electron microscopy, Periodic Acid Schiff (PAS) staining, immunohistochemical staining and in situ hybridization histochemistry.

RESULTS

As glomerulosclerosis progressed in the DRB group, expression of Ang1 mRNA and protein in glomeruli decreased and expression of TNF-alpha protein, Ang2 mRNA and protein in glomeruli increased. Expression of Ang1 mRNA and protein in glomeruli were negatively correlated with 24 h UPQM, Fn protein expression, and mean area of extracellular matrix (MAECM). In comparison, expression of Ang2 mRNA and protein in glomeruli were positively correlated with 24 h UPQM, Fn protein expression and MAECM; furthermore, there was a positive correlation between plasma Ang2 and 24 h UPQM. Plasma TNF-alpha and expression of TNF-alpha in glomeruli were positively correlated with expression of Ang2 mRNA and protein in glomeruli. There was a negative correlation between Ang1 protein expression and Ang2 protein expression in glomeruli.

CONCLUSION

During DRB-induced glomerulosclerosis, podocyte injury led to a shift in the balance of Ang1 and Ang2 in glomeruli. Increased TNF-alpha in plasma and glomeruli may upregulate Ang2 expression in glomeruli. Elevated Ang2 in both plasma and glomeruli may mediate protein permeability through the glomerular filtration barrier. Moreover, local expression of Ang2 may facilitate the progress of glomerulosclerosis by upregulating a component expression of extracellular matrix.

Expression and hormonal modulation of the thromboxane A2 receptor gene in mammalian testicular arteries

OBJECTIVE

Thromboxane A2 (TXA2) is a biologically potent arachidonate metabolite which causes vasoconstriction and platelet aggregation. This study aimed to evaluate the presence of TXA2 receptors in mammalian testicular arteries and the influence of exogenous gonadotropin administration on their expression.

DESIGN

Experimental study.

SETTING

Experimental animals in an academic research environment.

ANIMAL(S)

Seven rams aged 4-6 years, weighing 60-90 kg.

INTERVENTION(S)

Both testicular arteries of seven rams were extracted before (from one testis) and after (from the opposite testis) IV administration of 5,000 IU human chorionic gonadotropin (hCG).

MAIN OUTCOME MEASURE(S)

The expression of the TXA2 receptor gene was investigated by the real-time polymerase chain reaction. Data were analyzed by means of Student t test. Results were expressed as mean +/- standard deviation. A P value of <.01 was considered statistically significant.

RESULT(S)

Polymerase chain reaction revealed the presence of TXA2 messenger RNA receptor in all the basal samples, but the expression of TXA2 receptor gene was undetectable in all the arteries obtained 24 h after the administration of hCG.

CONCLUSION(S)

These preliminary results demonstrated for the first time the presence of TXA2 receptors in mammalian testicular arteries. Results also showed that their expression was down-regulated after hCG administration.

Human endocrine gland-derived vascular endothelial growth factor: expression early in development and in Leydig cell tumors suggests roles in normal and pathological testis angiogenesis

Angiogenesis is essential for tumor growth and metastasis. A new human angiogenic mitogen, endocrine gland-derived vascular endothelial growth factor (EG-VEGF), has been recently identified; its expression pattern is restricted to endocrine glands, with the highest expression in testis. We used in situ hybridization and newly generated monoclonal antibodies to investigate the expression of EG-VEGF in normal human prenatal and adult testis and in 48 human testicular tumors of different subtypes. We found that EG-VEGF was expressed from 14 wk until birth in human fetal testis. In the adult testis, EG-VEGF was strongly expressed only in Leydig cells. In testicular tumors, EG-VEGF was expressed specifically in Leydig cell tumors, whereas germ cell-derived neoplasms, including carcinoma in situ, seminoma, and nonseminomatous germ cell tumors, were negative for this antigen. In contrast, VEGF, another powerful angiogenic factor, was expressed in seminoma, but very weakly in Leydig cell tumors. Interestingly, we found that Leydig cell tumors presented vessel surface density 3.2-fold higher than seminoma. These findings argue that human EG-VEGF may play a role in angiogenesis both during the early endocrine development of testis and in the adult testis as well as in Leydig cell tumor growth.

Isolated small intestinal segments support auxiliary livers with maintenance of hepatic functions

We determine here the functional integrity of auxiliary livers in containers fashioned from the small intestine. Liver microfragments from dipeptidyl peptidase 4 (DPP4)-deficient rats were transplanted into syngeneic normal animals with isolated intestinal segments characterized by mucosal denudation but intact vascular supply. Transplanted liver fragments were restored to confluent tissue with normal hepatic architecture and development of DPP4-positive vessels, indicating angiogenesis and revascularization. Auxiliary liver units expressed multiple hepatotrophic and angiogenic genes, and transplanted tissues remained intact for up to the 6-week duration of the studies with neither ischemic injury nor significant hepatocellular proliferation. Hepatic metabolic, transport and synthetic functions were preserved in auxiliary livers, including uptake and biliary excretion of (99m)Tc-mebrofenin in syngeneic recipients of liver from F344 rats, as well as secretion of albumin in allografted Nagase analbuminemic rats. This ability to produce functionally competent auxiliary livers in vascularized intestinal segments offers therapeutic potential for liver disease and genetic deficiency.

Hormonal Regulation and Functional Role of Vascular Endothelial Growth Factor A in the Rat Testis1

Vascular endothelial cell growth factor (VEGF-A) is synthesized in the testis but its role and regulation in this organ have not been examined. VEGF and its receptors (VEGF-R) were quantified using reverse transcription-polymerase chain reaction and Western blot. VEGF, VEGF-R1, and VEGF-R2 mRNAs and VEGF protein were increased after treatment with 50 IU hCG. Injection of 100 ng human recombinant VEGF 165 into the testis caused an increase in endothelial cell proliferation, but only a moderate increase in testicular interstitial fluid volume. In contrast with systemic hCG treatment, local VEGF injection did not increase the permeability to intravenously injected colloidal carbon particles. However, if VEGF was given locally in the testes of animals pretreated with hCG 4 or 8 h earlier, VEGF acted in synergy with hCG to increase vascular carbon leakage by forming interendothelial cell gaps. Testicular blood flow was unaffected by local VEGF 165 injection. Treatment with a specific VEGF-R2 tyrosine kinase inhibitor blocked the hCG-induced increase in endothelial cell proliferation but did not affect the hCG-induced accumulation of polymorphonuclear leukocytes in testicular blood vessels or the increase in the testicular interstitial space. The present study demonstrated that testicular VEGF secretion is increased by hormonal stimulation of Leydig cells and that VEGF, through effects mediated via VEGF-R2, regulates endothelial cell proliferation in the rat testis. VEGF does not appear to regulate testicular blood flow and it is not involved in inducing the hCG-induced inflammation-like response in the testicular microvasculature. The permeability-increasing effect of VEGF is low in the testis under basal conditions but is apparently up-regulated by hCG treatment.