Stability analysis of vascular endothelial growth factor in cerebrospinal fluid.

Vascular endothelial growth factor (VEGF) is a promising biological marker and prognostic indicator in many neurological diseases. Although VEGF concentrations in plasma and cerebrospinal fluid (CSF) are increasingly reported, CSF-VEGF stability pre- and during-assay procedures is seldom evaluated. In the current study, we investigated VEGF variability and stability in CSF related to sample preparation, storage, and routine experimental procedures. Results showed that contaminant cell breakdown or aggregation can occur gradually before sample processing. However, after the removal of contaminant cell components, CSF-VEGF levels did not show significant changes in samples incubated at room temperature for 5 h, thawed/refrozen for 6 cycles. Samples preserved at -80 °C for up to 7 years continued to show measurable levels. Since some cellular components such as platelets contain a large amount of releasable VEGF, we conclude that CSF samples should be processed as soon as possible to carefully remove all cellular components and prevent possible consequent release of VEGF into CSF. After centrifugation to remove cellular contents, VEGF in CSF was relatively stable during routine experimental procedures and storage.

Development of normal reference values for seminal reactive oxygen species and their correlation with leukocytes and semen parameters in a fertile population.

Although reactive oxygen species (ROSs) are clearly implicated in the pathogenesis of male infertility, few studies have attempted to define the basal levels of ROSs in fertile men. Levels of ROSs are highly influenced by the presence of leukocytes and are associated with decreased seminal parameters. The objective of our study was to determine the normal ROS reference values in neat and washed semen of a fertile population and to correlate the leukocyte concentrations with seminal parameters. We evaluated 114 fertile men seeking vasectomy and 47 subfertile patients as a positive control. All samples were subjected to semen analysis and Endtz testing; chemiluminescence assay was used to determine ROS levels. All seminal parameters were significantly higher in the fertile men than in the subfertile patients. In nonleukocytospermic samples, ROS levels were lower in the fertile men than in the subfertile patients in neat (0.29 [0.18, 0.54] vs 0.94 [0.38, 1.51]) (P = .001) and washed semen (5.73 [1.90, 14.71] vs 23.4 [9.46, 115.55]) (P = .001). Similarly, in samples with leukocytes (Entdz, less than 1 x 10(6)/mL), ROS levels were lower in the fertile men in neat (0.75 [0.27, 1.71] vs 2.0 [0.97, 27.41]) (P = .001) and washed semen (15.85 [4.18, 62.16] vs 239.83 [33.4, 1193.75]) (P < .0001). As expected, samples with leukocytes had significantly higher ROS values in washed and neat semen. In the fertile population, ROSs were positively correlated with leukocytes and negatively correlated with sperm count and motility. In semen samples without leukocytes, the normality cutoff of ROSs was 0.55 x 10(4) counted photons per minute with 76.4% area under the curve (AUC) in the neat samples and 10.0 x 10(4) counted photons per minute with 77% AUC in the washed samples. In semen samples with leukocytes, the cutoff for ROSs in neat samples was 1.25 with 72.7% AUC and 51.5 with 81% AUC in the washed samples. We defined the cutoff levels of ROSs in a fertile population. Seminal leukocyte levels below 1 x 10(6)/mL were associated with increased ROSs. ROS levels were positively correlated with leukocytes and negatively correlated with sperm motility and concentration. Patients with normal seminal parameters and lower seminal leukocyte levels may benefit from therapeutic interventions that improve semen quality.

Vascular endothelial growth factor in the CSF of elderly patients with ventriculomegaly: variability, periodicity and levels in drainage responders and non-responders.

OBJECTIVES: The aim of this study was to examine lumbar CSF-VEGF levels from elderly patients with ventriculomegaly to evaluate the possible circadian or periodic concentration profile and relevance to the prediction of drainage response. METHODS: Lumbar CSF samples were collected in 1-h interval over 35 h from 22 patients with ventriculomegaly. CSF-VEGF levels were measured to elucidate the possible circadian or periodic concentration profiles. These VEGF levels were evaluated for correlations with clinical response to CSF drainage, ventricle size and other clinical information. RESULTS: The 35-h CSF-VEGF levels demonstrated a periodic concentration pattern with significant episodic fluctuation with 3-5h intervals. CSF-VEGF levels in non-responder group in which patients did not show clinical improvement with CSF drainage were significantly higher than these in responder group. CONCLUSION: VEGF variation in hydrocephalus patients suggests its possible pathophysiological role in hydrocephalus. The periodic concentration pattern of CSF-VEGF must be considered when choosing the most appropriate time for sample collection or clinical manipulation. Increased VEGF level in patients who showed no improvement with CSF drainage suggests that a possible greater ischemic or vascular injury may play a role in these patients. Pending further studies, these results suggest that high VEGF levels have a potential application in predicting non-responder patients with CSF drainage and so reducing the morbidity and cost of drainage and shunting in these patients.

VEGF/VEGFR-2 changes in frontal cortex, choroid plexus, and CSF after chronic obstructive hydrocephalus.

Chronic hydrocephalus (CH) is often associated with decreased cerebral blood flow (CBF) and oxygen levels. While the exact pathophysiology is not clear, vascular endothelial growth factor (VEGF) and its receptor-2 (VEGFR-2) may be involved. Because the choroid plexus (CP) is involved in cerebrospinal fluid (CSF) production and secretes numerous growth factors including VEGF, it is important to understand VEGF/VEGFR-2 levels in the CP-CSF circulatory system. Our results showed significant decreases in CBF and VEGFR-2 levels in frontal cortex (FC) in CH compared with SC; there were no significant changes in VEGF levels. CBF change in FC was positively correlated with VEGFR-2 levels (P=0.024). Immunohistochemistry (IHC) showed robust expression of VEGF/VEGFR-2 in CP. After CH induction, ventricular CSF volume and VEGF levels significantly increased. These results suggest that the decreased VEGFR-2 levels in FC may be contributed to decreased CBF and increased ventricular CSF-VEGF levels possibly reflected a hypoxic response and/or accumulation of VEGF from CP secretion after blockage of CSF outlet. Further investigation into CSF-VEGF levels in different sites may provide a better understanding of VEGF/VEGFR-2 modulation in the normal and hydrocephalic brain, and may represent a feasible approach to potential therapeutic options for hydrocephalus.

Dissociation between vascular endothelial growth factor receptor-2 and blood vessel density in the caudate nucleus after chronic hydrocephalus.

Chronic hydrocephalus (CH) is characterized by the presence of ventricular enlargement, decreased cerebral blood flow (CBF), and brain tissue oxygen delivery. Although the underlying pathophysiological role of vascular endothelial growth factor (VEGF) is not clear, ischemic-hypoxic events in CH are known to trigger its release. Previously, we have shown increased VEGF receptor-2 (VEGFR-2) and blood vessel density (BVd) in the hippocampus after CH. We investigated changes in neuronal and glial VEGFR-2 density and BVd in the caudate nucleus in an experimental model of CH. Animals with CH were divided into short term (ST, 2 to 4 weeks) and long term (LT, 12 to 16 weeks) and were compared with surgical controls (SCs, 12 to 16 weeks). The cellular and BVds were estimated using immunohistochemical and stereological counting methods. Overall, percentage (%)VEGFR-2 neurons were approximately two times greater in CH (ST, LT) than in SC. By comparison, glial cell %VEGFR-2 was greater by 10% to 17% in ST and 4% to 11% lower in LT compared with that in SC. Blood vessel density was significantly lower in CH than in SC in the superficial caudate. Changes in cerebrospinal fluid ventricular volume and pressure, as well as in CBF did not correlate with either VEGFR-2 or BVd. These observed findings suggest that destructive forces may outweigh angiogenic forces and possibly show a disassociation between VEGFR-2 and BV expressions.

Pathogenic mechanisms in endometriosis-associated infertility.

OBJECTIVE: To review the mechanisms by which endometriosis may affect reproductive function. DESIGN: Review of the English literature from 1986 to 2007 after searching Medline, EMBASE, Cochrane, and BIOSIS, as well as relevant meeting abstracts. SETTING: Fertility research center and obstetrics and gynecology department in a tertiary care hospital. RESULT(S): There is compelling evidence in the literature that endometriosis has detrimental effects on ovarian and tubal function and uterine receptivity, resulting in female infertility. The mechanisms of infertility associated with endometriosis remain controversial and include abnormal folliculogenesis, elevated oxidative stress, altered immune function, and hormonal milieu in the follicular and peritoneal environments, and reduced endometrial receptivity. These factors lead to poor oocyte quality, impaired fertilization, and implantation. CONCLUSION(S): Through unraveling the mechanisms by which endometriosis leads to infertility, researchers are sure to find a nonsurgical means to diagnose endometriosis, most likely through serum and peritoneal markers. Cytokines, interleukins, oxidative stress markers, and soluble cellular adhesion molecules all show potential to be used as a reliable marker for diagnosing endometriosis. After analyzing the pathogenic mechanisms of endometriosis, it seems that the future treatment of this entity may include cyclo-oxygenase-2 inhibitors, immunomodulators, or hormonal suppressive therapy to eliminate the need for surgical treatment of endometriosis.

Role of oxidative stress in endometriosis.

Endometriosis is a chronic pleomorphic disorder with pelvic or systemic manifestations, and is characterized by the presence of endometrial glands and stroma. In the United States, the prevalence of the disease is estimated to range from 2 to 50% in women of reproductive age. No single theory can explain the histogenesis and the pleomorphic manifestations of endometriosis. Endometriosis is being reported in younger age women and manifesting with increasing severity, hence the need to understand the role of oxidative stress (OS) in endometriosis. The presence of elevated concentrations of free radicals and lowered antioxidant potential leads to OS. The development of OS in the local peritoneal environment may be one of the links in the chain of events leading to endometriosis. Redox levels may modulate the severity and the dynamics of endometriosis and progression of the disease. OS has been implicated in infertility associated with endometriosis. Recent literature reviewed investigates the role of molecular mechanisms and genetic pathways that may modulate cellular response to OS. Antioxidant supplementation, immunomodulators, and selective progesterone receptor modulators with antioxidant effects have been investigated as possible treatments for endometriosis, but compelling evidence on the benefits of the various modalities is lacking. Results of the limited number of animal and human trials need to be corroborated by larger randomized controlled trials.