Estrogen regulation of neurotrophin expression in sympathetic neurons and vascular targets

NGF Prevents Loss of TrkA/VEGFR2 Cells, and VEGF Isoform Dysregulation in the Retina of Adult Diabetic Rats

Among the factors involved in diabetic retinopathy (DR), nerve growth factor (NGF) and vascular endothelial growth factor A (VEGFA) have been shown to affect both neuronal survival and vascular function, suggesting that their crosstalk might influence DR outcomes. To address this question, the administration of eye drops containing NGF (ed-NGF) to adult Sprague Dawley rats receiving streptozotocin (STZ) intraperitoneal injection was used as an experimental paradigm to investigate NGF modulation of VEGFA and its receptor VEGFR2 expression. We show that ed-NGF treatment prevents the histological and vascular alterations in STZ retina, VEGFR2 expression decreased in GCL and INL, and preserved the co-expression of VEGFR2 and NGF-tropomyosin-related kinase A (TrkA) receptor in retinal ganglion cells (RGCs). The WB analysis confirmed the NGF effect on VEGFR2 expression and activation, and showed a recovery of VEGF isoform dysregulation by suppressing STZ-induced VEGFA₁₂₁ expression. Reduction in inflammatory and pro-apoptotic intracellular signals were also found in STZ+NGF retina. These findings suggest that ed-NGF administration might favor neuroretina protection, and in turn counteract the vascular impairment by regulating VEGFR2 and/or VEGFA isoform expression during the early stages of the disease. The possibility that an increase in the NGF availability might contribute to the switch from the proangiogenic/apoptotic to the neuroprotective action of VEGF is discussed.

Improvement of Cognitive Function in Ovariectomized Rats by Human Neural Stem Cells Overexpressing Choline Acetyltransferase via Secretion of NGF and BDNF

Menopause is associated with memory deficits attributed to reduced serum estrogen levels. We evaluated whether an increase in brain-derived neurotrophic factor (BDNF) and nerve-growth factor (NGF) levels, through transplantation of choline acetyltransferase (ChAT)-overexpressing neural stem cells (F3.ChAT), improved learning and memory in ovariectomized rats. PD13 mouse neuronal primary culture cells were treated with estradiol or co-cultured with F3.ChAT cells; choline transporter1 (CHT1), ChAT, and vesicular acetylcholine transporter (VAChT) expression was evaluated using real-time PCR. The relationship between estrogen receptors (ERs) and neurotrophin family members was analyzed using immunohistochemistry. After the transplantation of F3.ChAT cells into OVx rats, we evaluated the memory, ACh level, and the expression of ER, neurotrophin family proteins, and cholinergic system. Estradiol upregulated CHT1, ChAT, and VAChT expression in ER; they were co-localized with BDNF, NGF, and TrkB. Co-culture with F3.ChAT upregulated CHT1, ChAT, and VAChT by activating the neurotrophin signalling pathway. Transplantation of F3.ChAT cells in OVX animals increased the ACh level in the CSF and improved memory deficit. In addition, it increased the expression of ERs, neurotrophin signaling, and the cholinergic system in the brains of OVX animals. Therefore, the estradiol deficiency induced memory loss by the down-regulation of the neurotrophin family and F3.ChAT could ameliorate the cognitive impairment owing to the loss or reduction of estradiol.

17β-Oestradiol facilitates M2 macrophage skewing and ameliorates arrhythmias in ovariectomized female infarcted rats

Epidemiological studies have suggested a lower incidence of arrhythmia‐induced sudden cardiac death in women than in men. 17β‐oestradiol (E2) has been reported to have a post‐myocardial infarction antiarrhythmic effect, although the mechanisms have yet to be elucidated. We investigated whether E2‐mediated antioxidation regulates macrophage polarization and affects cardiac sympathetic reinnervation in rats after MI. Ovariectomized Wistar rats were randomly assigned to placebo pellets, E2 treatment, or E2 treatment +3‐morpholinosydnonimine (a peroxynitrite generator) and followed for 4 weeks. The infarct sizes were similar among the infarcted groups. At Day 3 after infarction, post‐infarction was associated with increased superoxide levels, which were inhibited by administering E2. E2 significantly increased myocardial IL‐10 levels and the percentage of regulatory M2 macrophages compared with the ovariectomized infarcted alone group as assessed by immunohistochemical staining, Western blot and RT‐PCR. Nerve growth factor colocalized with both M1 and M2 macrophages at the magnitude significantly higher in M1 compared with M2. At Day 28 after infarction, E2 was associated with attenuated myocardial norepinephrine levels and sympathetic hyperinnervation. These effects of E2 were functionally translated in inhibiting fatal arrhythmias. The beneficial effect of E2 on macrophage polarization and sympathetic hyperinnervation was abolished by 3‐morpholinosydnonimine. Our results indicated that E2 polarized macrophages into the M2 phenotype by inhibiting the superoxide pathway, leading to attenuated nerve growth factor‐induced sympathetic hyperinnervation after myocardial infarction.

Estrogen-dependent regulation of transient receptor potential vanilloid 1 (TRPV1) and P2X purinoceptor 3 (P2X3): Implication in burning mouth syndrome

Sex differences in the nervous system have gained recent academic interest. While the prominent differences are observed in mood and anxiety disorders, growing number of evidences also suggest sex difference in pain perception. This review focuses on estrogen as the key molecule underlying such difference, because estrogen plays many functions in the nervous system, including modulation of transient receptor potential vanilloid 1 (TRPV1) and P2X purinoceptor 3 (P2X3), two important nociceptive receptors. Estrogen was shown in various studies to up-regulate TRPV1 expression through two distinct pathways, resulting in pro-nociceptive effect. However, estrogen alleviated pain in other studies, by down-regulating nerve growth factor (NGF)-activated pathways and TRPV1. Estrogen may also attenuate nociception by inhibiting P2X3 receptors and ATP-signaling. Understanding the mechanism underlying the pro- and anti-nociceptive effect of estrogen might be crucial to understand pathophysiology of the burning mouth syndrome (BMS), a common chronic orofacial pain disorder in menopausal women. The involvement of TRPV1 is strongly suspected because of burning sensation. Reduced estrogen level of the BMS patient might have caused increased activity of P2X3 receptors. Interestingly, the increased expression of TRPV1 and P2X3 in oral mucosa of BMS patients was reported. The combinational impact of differential modulation of TRPV1/P2X3 during menopause might be an important contributing factor of etiology of BMS. Understanding the estrogen-dependent regulation of nociceptive receptors may provide a valuable insight toward the peripheral mechanism of sex-difference in pain perception.

Estrogen Regulation of the Expression of Pain Factor NGF in Rat Chondrocytes

OBJECTIVE

Pain is the main symptom of osteoarthritis (OA). Nerve growth factor (NGF) plays a crucial role in the generation of OA pain. And estrogen-alone used resulted in a sustained joint pain reduction in postmenopausal women. So we aim to find whether estrogen alters chondrocytes' NGF level, affecting OA pain.

METHODS

Primary chondrocytes and cartilage explants isolated from Sprague Dawley rat knees were cultured with physiological concentrations of estrogen (17β-Estradiol ≥ 98%, E2), Estrogen Receptor α (ERα) inhibitor and stimulants. Then, chondrocytes NGF mRNA expression and protein release were analyzed by a quantitative real-time polymerase chain reaction (qPCR) and enzyme-linked immunosorbent assay (ELISA) respectively. Additionally, cultures were pre-incubated with MEK-ERK inhibitor to identify the signaling pathway that estrogen alters NGF mRNA and protein levels.

RESULTS

We found that chondrocytes NGF expression and release were decreased by E2. E2 also reduced chondrocytes IL-1β-stimulated or TGF-β1-stimulated NGF expression. Phosphorylated extracellular signal-regulated kinasep1/2 (p-ERK1/2) signals were detected stronger than the control group by Western Blotting (WB). When we cultured chondrocytes with PD98059 (MEK-ERK inhibitor, PD), NGF mRNA expression was added to 1.41Ct (2.07±0.1 fold).

CONCLUSION

We showed that E2 reduces chondrocytes NGF expression significantly, even after stimulation by TGF-β1 or IL-1β. MEK-ERK signaling is involved in this process.

Developmental exposure to DDT or DDE alters sympathetic innervation of brown adipose in adult female mice

BACKGROUND

Exposure to the bioaccumulative pesticide dichlorodiphenyltrichloroethane (DDT) and its metabolite dichlorodiphenyldichloroethylene (DDE) has been associated with increased risk of insulin resistance and obesity in humans and experimental animals. These effects appear to be mediated by reduced brown adipose tissue (BAT) thermogenesis, which is regulated by the sympathetic nervous system. Although the neurotoxicity of DDT is well-established, whether DDT alters sympathetic innervation of BAT is unknown. We hypothesized that perinatal exposure to DDT or DDE promotes thermogenic dysfunction by interfering with sympathetic regulation of BAT thermogenesis.

METHODS

Pregnant C57BL/6 J mice were administered environmentally relevant concentrations of DDTs (p,p'-DDT and o,p'-DDT) or DDE (p,p'-DDE), 1.7 mg/kg and 1.31 mg/kg, respectively, from gestational day 11.5 to postnatal day 5 by oral gavage, and longitudinal body temperature was recorded in male and female offspring. At 4 months of age, metabolic parameters were measured in female offspring via indirect calorimetry with or without the β3 adrenergic receptor agonist, CL 316,243. Immunohistochemical and neurochemical analyses of sympathetic neurons innervating BAT were evaluated.

RESULTS

We observed persistent thermogenic impairment in adult female, but not male, mice perinatally exposed to DDTs or p,p'-DDE. Perinatal DDTs exposure significantly impaired metabolism in adult female mice, an effect rescued by treatment with CL 316,243 immediately prior to calorimetry experiments. Neither DDTs nor p,p'-DDE significantly altered BAT morphology or the concentrations of norepinephrine and its metabolite DHPG in the BAT of DDTs-exposed mice. However, quantitative immunohistochemistry revealed a 20% decrease in sympathetic axons innervating BAT in adult female mice perinatally exposed to DDTs, but not p,p'-DDE, and 48 and 43% fewer synapses in stellate ganglia of mice exposed to either DDTs or p,p'-DDE, respectively, compared to control.

CONCLUSIONS

These data demonstrate that perinatal exposure to DDTs or p,p'-DDE impairs thermogenesis by interfering with patterns of connectivity in sympathetic circuits that regulate BAT.

Strength in diversity: Understanding the pathways to herpes simplex virus reactivation

Herpes simplex virus (HSV) establishes a latent infection in peripheral neurons and can periodically reactivate to cause disease. Reactivation can be triggered by a variety of stimuli that activate different cellular processes to result in increased HSV lytic gene expression and production of infectious virus. The use of model systems has contributed significantly to our understanding of how reactivation of the virus is triggered by different physiological stimuli that are correlated with recrudescence of human disease. Furthermore, these models have led to the identification of both common and distinct mechanisms of different HSV reactivation pathways. Here, we summarize how the use of these diverse model systems has led to a better understanding of the complexities of HSV reactivation, and we present potential models linking cellular signaling pathways to changes in viral gene expression.

Porcine dorsal root ganglia ovarian neurons are affected by long lasting testosterone treatment

We studied the effect of testosterone overdose on the number, distribution and chemical coding of ovarian neurons in the dorsal root ganglia (DRGs) in pigs. On day 3 of the estrous cycle, the ovaries of both the control and experimental gilts were injected with retrograde tracer Fast Blue. From day 4 of the estrous cycle to the expected day 20 of the second studied cycle, the experimental gilts were injected with testosterone, while the control gilts received oil. After the completion of the protocol the Th16-L5 DRGs were collected. Injections of testosterone increased the testosterone (~3.5 fold) and estradiol-17beta (~1.6 fold) levels in the peripheral blood, and reduced the following in the DRGs: the total number of the Fast Blue-positive perikarya, the population of perikarya in the L2-L4 ganglia, and the numbers of SP(+)/CGRP(+), SP(+)/PACAP(+), SP(+)/nNOS(+) and SP(-)/nNOS(+) perikarya. In the testosterone-injected gilts, the populations of SP(+)CGRP(-), small and large androgen receptors-expressing perikarya were increased. These results suggest that elevated androgen levels during pathological states may regulate the transmission of sensory modalities from the ovary to the spinal cord, and antidromic regulation of the ovarian functions.

Long-term treatment with testosterone alters ovary innervation in adult pigs

BACKGROUND

Intraovarian distribution and density of nerve fibres immunoreactive (IR) to protein gene product 9.5 (PGP 9.5) and containing dopamine-β-hydroxylase (DβH), neuropeptide Y (NPY), somatostatin (SOM), galanin (GAL) were determined.

METHODS

From day 4 of the first oestrous cycle to day 20 of the second studied cycle, experimental gilts (n = 3) were injected with testosterone (T), while control gilts (n = 3) received corn oil.

RESULTS

After T administration the numbers of fibres IR to PGP 9.5 and fibres IR to DβH, NPY and SOM were decreased. Fewer PGP 9.5- and DβH-IR terminals were observed within the ground plexus and around arteries and medullar veins, and medium tertiary follicles, and DβH-IR terminals in the vicinity of small tertiary follicles. T decreased the density of NPY-IR fibres in the medullar part of the ground plexus, and SOM-IR in the cortical part of the ground plexus.

CONCLUSIONS

The obtained data show that long-term T treatment of gilts decreases the total number of intraovarian fibres, including sympathetic ones. These results suggest that elevated T levels that occur during pathological states may affect the innervation pattern of ovaries, and their function(s).

Potential role of estrogen in maintaining the imbalanced sympathetic and sensory innervation in endometriosis

Endometriosis, one of the most common benign gynecological diseases, affects millions of women of childbearing age. Endometriosis-associated pain is a major cause of disability and compromised quality of life in women. Neuropathic mechanisms are believed to play an important role. An imbalanced sympathetic and sensory innervation (reduced sympathetic innervation, with unchanged or increased sensory innervation in endometriotic lesions) has been demonstrated in endometriosis in recent studies. And it is believed to contribute to the pathogenesis of endometriosis-associated pain. It is primarily considered to be a natural adaptive program to endometriosis-associated inflammation. However, it is important to further clarify whether other potential modulating factors are involved in this dysregulation. It is generally accepted that endometriosis is an estrogen dependent disease. Higher estrogen biosynthesis and lower estrogen inactivation in endometriosis can lead to an excess of local estrogen in endometriotic lesions. In addition to its proliferative and anti-inflammatory actions, local estrogen in endometriosis also exerts potential neuromodulatory effects on the innervation in endometriosis. The aim of this review is to highlight the role of estrogen in mediating this imbalanced sympathetic and sensory innervation in endometriosis, through direct and indirect mechanisms on sympathetic and sensory nerves. Theoretical elaboration of the underlying mechanisms provides new insights in supporting the therapeutic role of estrogen in endometriosis-associated pain.

Expression of PTHrP and PTH/PTHrP receptor 1 in the superior cervical ganglia of rats

PTHrP and its receptor PTHR1 are found in the CNS and peripheral nervous system. The presence of PTHrP mRNA has been detected in the superior cervical ganglion (SCG), but there are no data on the cellular distribution of PTHrP and PTHR1 in the SCG. Although it is known that ovarian activity and reproductive status influence sympathetic activity, and the PTHrP/PTHR1 system is influenced by estrogens in different tissues, it is not known whether these factors have a similar effect on expression of PTHrP and PTHR1 in the nervous system. Hence, we investigated the presence and distribution of PTHrP and PTHR1 in neurons and glia of the SCG of rats, as well as the influence of ovariectomy on their expression, by using immunohistochemistry. PTHrP and PTHR1 immunoreactivity was observed in cytoplasm as well as in nuclei of almost all neurons in the SCG. In male rats, intensity of PTHrP fluorescence was significantly higher in cytoplasm of NPY-, in comparison to NPY+ neurons (p < 0.05). In female rats, 2 months post-ovariectomy, significantly lower intensity of PTHrP fluorescence in cytoplasm of the SCG neurons was observed in comparison to sham operated animals (p < 0.05). In addition to neurons, PTHrP and PTHR1 immunoreactivity was observed in most of the glia and was not influenced by ovariectomy. Results show the expression of PTHrP and its receptor, PTHR1, in the majority of neurons and glial cells in the SCG of rats. Expression of PTHrP, but not PTHR1 in the cytoplasm of SCG neurons is influenced by ovarian activity.

Sex-specific association between nerve growth factor polymorphism and cardiac vagal modulation

OBJECTIVE

Substantial research has shown that anxiety disorders are associated with decreased cardiac vagal tone, which is a known risk factor for cardiac vulnerability. A functional nerve growth factor (NGF) polymorphism (rs6330, c.104C > T, p.Ala35Val) has been associated with anxiety such that in males but not females, T-allele carriers exhibit higher levels of trait anxiety. Here we investigate whether the nonsynonymous NGF variant has an effect on cardiac autonomic control.

METHODS

From 705 adults initially screened for medical and psychiatric illnesses, a final cohort of 580 healthy Han Chinese (352 men, 228 women; mean [standard deviation] age = 34.46 [8.45] years) was included in the NGF genotyping (C/C: 428% [73.8%] and T-allele carriers: 152% [26.2%]). Short-term heart rate variability was used to assess cardiac autonomic function.

RESULTS

There were significant genotype-by-sex interaction effects (p < .05) on high-frequency power (HF) and root mean square of successive heartbeat interval differences (RMSSD), both indices of cardiac vagal control. Even after adjusting for possible confounders, men with any T allele showed lower HF and RMSSD compared with men with the C/C genotype. Women, however, showed an opposite but nonsignificant pattern.

CONCLUSIONS

The studied NGF polymorphism modulates autonomic outflow to the heart in a sex-dependent manner. The findings support the view that male T-allele carriers are at increased susceptibility for anxiety by association with low vagal activity and suggest a potential sex-specific genetic link between the highly comorbid anxiety disorders and cardiovascular diseases.

The role of sympathectomy on the regulation of basilar artery volume changes in stenoocclusive carotid artery modeling after bilateral common carotid artery ligation: an animal model

BACKGROUND

Stenoocclusive carotid artery disease causes important histomorphologic changes in all craniocervical vasculatures, such as luminal enlargement, vascular wall thinning, elongation, convolutions, and aneurysm formation in the posterior circulation. Although increased pressure, retrograde blood flow, and biochemical factors are described in the pathogenesis of vascular remodelisation, the vasoregulatory role of the autonomic nervous system has not been investigated thus far. We investigated the relationship between the sympathetic nervous system and the severity of histomorphologic alterations of basilar arteries after bilateral common carotid artery ligation (BCCAL).

MATERIAL AND METHODS

This study was conducted on 21 rabbits. The rabbits were randomly divided into three groups: baseline group (n = 5), sympathectomy non-applied group (SHAM; n = 8), and sympathectomy applied group (n = 8) before bilateral common carotid artery ligation. Permanent ligation of the prebifurcations of the common carotid arteries was performed to replicate stenoocclusive caroid artery disease. Basilar artery volumes were measured after ligation. Volumes of the basilar arteries were estimated by stereologic methods and compared between groups.

RESULTS

Luminal enlargement, wall thinning, elongation, convolutions, and doligoectatic configurations were detected in the majority of basilar arteries. The mean basilar arterial volume was 4.27 ± 0.22 mm3 in the baseline group; 5.28 ± 0.67 mm(3) in the SHAM group, and 8.84 ± 0.78 mm3 in the study group. The severity of basilar enlargement was significantly higher in the study group compared with the SHAM (p < 0.005) and baseline groups (p < 0.001).

CONCLUSIONS

Sympathectomy causes basilar artery enlargment, which is beneficial for maintaining cerebral blood flow; however, it also causes wall thinning, elongation, convolution, and aneurysm formation, which may be hazardous in stenoocclusive carotid artery disease. Sympathectomy can prevent new vessel formation and hyperthyrophic changes at the posterior circulation. Neovascularisation is not detected adequately in sympathectomised animals.

Long-term testosterone administration affects the number of paracervical ganglion ovary-projecting neurons in sexually mature gilts

The influence of testosterone (T) overdose on the number and distribution of ovarian neurons in the paracervical ganglion (PCG) in pigs was examined. To identify the ovarian neurons, on day 3 of the estrous cycle, the ovaries of both the control and experimental gilts were injected with retrograde neuronal tracer Fast Blue. From next day to the expected day 20 of the second studied cycle, experimental gilts were injected with T, while control gilts received oil. The PCG was then collected and processed for double-labeling immunofluorescence. T injections increased the T (∼3.5-fold) and estradiol-17β (∼1.6-fold) levels in the peripheral blood, and reduced the following in the PCG: the total number of Fast Blue-positive neurons, the number of perikarya in the lateral part of the PCG, the numbers of VAChT(+)/SOM(+), VAChT(+)/VIP(+), VAChT(+)/nNOS(+), VAChT(+)/VIP(-), VAChT(+)/DβH(-), VAChT(-)/SOM(-), VAChT(-)/VIP(-), VAChT(-)/nNOS(-) and VAChT(-)/DβH(-) perikarya, In the T-affected PCG, the populations of ovarian perikarya coded VAChT(-)/SOM(+), VAChT(-)/VIP(+) and VAChT(-)/DβH(+), and expressing androgen receptor were increased. After T treatment within the PCG dropped the density of nerve fibers expressing VAChT and/or SOM, VIP, DβH. Obtained data suggest that elevated androgen levels occurring during pathological processes may regulate ovary function(s) by affecting the PCG gonad-supplying neurons.

Reduction of the number of neurones in the caudal mesenteric ganglion innervating the ovary in sexually mature gilts following testosterone administration

The effect of testosterone on the morphological and chemical plasticity of the porcine caudal mesenteric ganglion (CaMG) ovary-projecting neurones was investigated. To identify the neurones on day 3 of the oestrous cycle, the ovaries of both the control and experimental gilts were injected with Fast Blue retrograde neuronal tracer. From next day until day 20 of the anticipated second studied cycle, experimental gilts were injected with testosterone, whereas control gilts received oil. Testosterone injections increased testosterone (by approximately 3.5-fold) and 17β-oestradiol (by approximately 1.6-fold) levels in the peripheral blood and decreased the following in the CaMG: the total number of Fast Blue-positive perikarya (including small ones); the population of small perikarya in the caudal, ventral and dorsal ganglional regions; the numbers of dopamine-β-hydroxylase (DβH) and/or neuropeptide Y (NPY), somatostatin (SOM), galanin (GAL) small and large perikarya; the numbers of small perikarya containing DβH (but not NPY, SOM, GAL); and the density of DβH and/or NPY, SOM nerve fibres. A disappearance of small and large non-noradrenergic perikarya and an increase in the total number of androgen receptor-immunoreactive perikarya was noted. Our results suggest that elevated androgen levels occurring during pathological states may regulate ovary function(s) by affecting the CaMG gonad-supplying neurones.

Long-term estradiol-17β administration changes the population of paracervical ganglion neurons supplying the ovary in adult gilts

The aim of this study was to determine the influence of estradiol-17β (E(2)) overdose on the number and distribution of ovarian parasympathetic neurons in the paracervical ganglion (PCG) in adult pigs. To identify the neurons innervating gonads on day 3 of the estrous cycle, the ovaries of both the control and experimental gilts were injected with retrograde neuronal tracer Fast Blue. From next day to the expected day 20 of the second studied cycle, experimental gilts were injected with E(2), while control gilts received oil. The PCG were then collected and processed for double-labeling immunofluorescence. Injections of E(2) increased the E(2) level in the peripheral blood approximately four- to fivefold and reduced the following in the PCG: the total number of Fast Blue-positive neurons; the number of perikarya in the lateral part of the PCG; the numbers of vesicular acetylcholine transporter (VAChT)(+)/somatostatin(+), VAChT(+)/vasoactive intestinal polypeptide (VIP)(+), VAChT(+)/neuronal isoform of nitric oxide synthase(+), VAChT(+)/VIP(-), VAChT(+)/dopamine β-hydroxylase (DβH)(-), VAChT(-)/VIP(-), and VAChT(-)/DβH(-) perikarya; and the total number of perikarya expressing estrogen receptors (ERs) subtype α and/or β. In summary, long-term E(2) treatment of adult gilts downregulates the population of both cholinergic and ERs expressing the PCG ovary-projecting neurons. Our results suggest that elevated E(2) levels occurring during pathological states may regulate gonadal function(s) by affecting ovary-supplying neurons.

Long term estradiol-17β administration changes population of the dorsal root ganglia neurons innervating the ovary in the sexually mature gilts

The influence of estradiol-17β (E₂) overdose on the number and distribution of neurons in the dorsal root ganglia (DRGs) supplying the ovary of adult pigs was investigated. The numbers of ovarian substance P (SP)-, calcitonin gene-related peptide (CGRP)-, galanin (GAL)-, pituitary adenylate cyclase-activating polypeptide (PACAP)-, neuronal isoform of nitric oxide synthase (nNOS)- and estrogen receptors (ERs)-immunoreactive perikarya were also determined. On day 3 of the estrous cycle, the ovaries of both the control and experimental gilts were injected with retrograde tracer Fast Blue. From day 4 of the estrous cycle to the expected day 20 of the second studied cycle, the experimental gilts were injected with E₂, while the control gilts received oil. The DRGs Th16-L5 were then collected and processed for double-labelling immunofluorescence. Injections of E₂ increased the E₂ level in the peripheral blood ∼4-5-fold and reduced the following in the DRGs: the total number of Fast Blue-positive perikarya, the number of large perikarya, the population of perikarya in the L2 and L3 ganglia, the numbers of SP- and/or CGRP-, PACAP-, nNOS-immunoreactive perikarya and the number of large perikarya expressing ERs subtype α and β. These results show that long-term E₂ treatment of adult gilts affects both the spatial and neurochemical organization pattern of ovary sensory innervation. Our findings suggest that elevated E₂ levels occurring during pathological states may regulate the transmission of sensory modalities from the ovary to the spinal cord.

Stellate ganglion block for the management of hot flashes and sleep disturbances in breast cancer survivors: an uncontrolled experimental study with 24 weeks of follow-up

BACKGROUND

We studied the stellate ganglion block (SGB) recently suggested for the treatment of severe vasomotor symptoms and sleep disturbances in breast cancer survivors. Following an initial pilot study, which focused on the acceptability and safety of SGB for this important problem, we evaluated its short- and long-term efficacy.

MATERIALS AND METHODS

Postmenopausal breast cancer survivors with severe vasomotor symptoms resistant to standard nonhormonal pharmacological intervention were eligible. Diaries were used to measure daily hot flash scores (frequency and intensity) and sleep quality (Pittsburgh Sleep Quality Index) during scheduled visits at baseline, 1, 4, 12 and 24 weeks following the SGB. Efficacy data were analyzed using longitudinal regression models.

RESULTS

Thirty-four patients participated and none refused the SGB procedure. Most patients received more than one SGB. The pilot study found SGB to be safe. In the main study, hot flash scores were reduced from baseline by 64% [95% confidence interval (CI) -74% to -49%] and 47% (95% CI -62% to -27%) at weeks 1 and 24, respectively. The odds ratio of better sleep quality relative to baseline was 3.4 at week 1 (95% CI 1.6-7.2) and 4.3 at week 24 (95% CI 1.9-9.8).

CONCLUSION

In the short term, SGB appears to be an effective treatment with acceptable morbidity for some breast cancer survivors with therapy-resistant vasomotor symptoms and/or sleep disturbances. Although sleep quality was maintained out to 24 weeks the efficacy of SGB for hot flashes was reduced over time. A randomized controlled trial is needed to confirm these findings.

Sex, hormones and neuroeffector mechanisms

Incidence and rate of cardiovascular disease differ between men and women across the life span. Although hypertension is more prominent in men than women, there is a group of vasomotor disorders [i.e. Raynaud's disease, postural orthostatic tachycardia syndrome and vasomotor symptoms (hot flashes) of menopause and migraine] with a female predominance. Both sex and hormones interact to modulate neuroeffector mechanisms including integrated regulation of the Sry gene and direct effect of sex steroid hormones on synthesis, release and disposition of monoamine neurotransmitters, and distribution and sensitivity of their receptors in brain areas associated with autonomic control. The interaction of the sex chromosomes and steroids also modulates these effector tissues, that is, the heart, vascular smooth muscle and endothelium. Although involvement of central serotonergic centres has been studied in regard to mood disorders such as depression, their contribution to cardiovascular risk is gaining attention. Studies are needed to further evaluate how hormonal treatments and drugs used to modulate adrenergic and serotonergic activity affect progression and risk for cardiovascular disease in men and women.

Long-term estradiol-17β administration reduces population of neurons in the sympathetic chain ganglia supplying the ovary in adult gilts

Elevated levels of endogenous estrogens occurring in the course of pathological states of ovaries (follicular cysts, tumors) as well as xenoestrogens may result in hyperestrogenism. In rat, a close relationship between estrogens and sympathetic and sensory neurons supplying the genito-urinary system was reported. Recently, we have shown that long-term estradiol-17β (E(2)) administration affected morphological and immunochemical organization of the sympathetic ovarian neurons in the caudal mesenteric ganglion of adult gilts. In this study, the influence of E(2) overdose on the number and distribution of neurons in the sympathetic chain ganglia (SChG) projecting to the ovary of adult pigs was investigated. The numbers of ovarian dopamine-β-hydroxylase (DβH-), neuropeptide Y (NPY-), somatostatin (SOM-), galanin (GAL-) and estrogen receptors (ERs-) immunoreactive perikarya as well as the density of the intraganglionic nerve fibers containing DβH and/or NPY, SOM, GAL were also determined. On day 3 of the estrous cycle the ovaries of both the control and experimental gilts were injected with retrograde neuronal tracer Fast Blue, to identify the neurons innervating gonads. From day 4 of the estrous cycle to the expected day 20 of the second studied cycle, the experimental gilts were injected with E(2), while the control gilts were receiving oil. After the last E(2)/oil injection, the SChG Th16-S2 were collected and processed for double-labeling immunofluorescence. Injections of E(2): (1) increased the E(2) level in the peripheral blood ~4-5 fold, (2) reduced the total number of Fast Blue-positive postganglionic neurons in the ganglia under investigation, (3) decreased the number of perikarya in the L2-L4 ganglia, (4) reduced the number of perikarya in the ventral, dorsal and central regions of the SChG, (5) decreased the numbers of DβH(+)/NPY(+) and DβH(+)/GAL(+) perikarya and the numbers of DβH(+) but NPY(-), SOM(-) and GAL(-) perikarya in the SChG, (6) decreased the number of perikarya expressing ERs subtype α and β, and (7) decreased the total number of the intraganglionic nerve fibers containing DβH and/or NPY. These results show that long-term E(2) treatment of adult gilts down-regulates the population of both noradrenergic and ERs expressing the SChG ovary supplying neurons. Our findings suggest also that elevated E(2) levels that occur during pathological states may regulate gonadal function(s) by affecting ovary supplying neurons.

Chronic pelvic pain and endometriosis: translational evidence of the relationship and implications

BACKGROUND

Many clinicians and patients believe that endometriosis-associated pain is due to the lesions. Yet causality remains an enigma, because pain symptoms attributed to endometriosis occur in women without endometriosis and because pain symptoms and severity correlate poorly with lesion characteristics. Most research and reviews focus on the lesions, not the pain. This review starts with the recognition that the experience of pain is determined by the central nervous system (CNS) and focuses on the pain symptoms.

METHODS

Comprehensive searches of Pubmed, Medline and Embase were conducted for current basic and clinical research on chronic pelvic pain and endometriosis. The information was mutually interpreted by a basic scientist and a clinical researcher, both in the field of endometriosis. The goal was to develop new ways to conceptualize how endometriosis contributes to pain symptoms in the context of current treatments and the reproductive tract.

RESULTS

Endometriotic lesions can develop their own nerve supply, thereby creating a direct and two-way interaction between lesions and the CNS. This engagement provides a mechanism by which the dynamic and hormonally responsive nervous system is brought directly into play to produce a variety of individual differences in pain that can, in some women, become independent of the disease itself.

CONCLUSIONS

Major advances in improving understanding and alleviating pain in endometriosis will likely occur if the focus changes from lesions to pain. In turn, how endometriosis affects the CNS would be best examined in the context of mechanisms underlying other chronic pain conditions.

Long-term estradiol-17β administration decreases the number of neurons in the caudal mesenteric ganglion innervating the ovary in sexually mature gilts

The effect of estradiol-17β (E(2)) on the number and distribution of neurons in the caudal mesenteric ganglion (CaMG) supplying the ovary of adult pigs was investigated. Also, the numbers of ovarian dopamine-β-hydroxylase (DβH-), neuropeptide Y (NPY-), somatostatin (SOM-), galanin (GAL-) and estrogen receptor (ER)-immunoreactive perikarya as well as the density of the intraganglionic nerve fibers containing DβH and/or NPY, SOM, GAL were determined. E(2) was administered i.m. from day 4 of the first studied estrous cycle to the expected day 20 of the second studied cycle. Injections of E(2) (1) increased the E(2) level in the peripheral blood approximately 4-5 fold, (2) decreased the number of small-sized Fast Blue-positive postganglionic neurons in the CaMG, (3) decreased the number of small perikarya in the ventral, dorsal and central regions of the CaMG, (4) decreased the number of large perikarya in the dorsal and central regions, (5) decreased the number of small and large perikarya in the CaMG that were DβH(+)/NPY(+), (6) decreased the number of small DβH(+) but NPY(-) perikarya, (7) decreased the number of small perikarya coded DβH(+)/SOM(+) and DβH(+)/SOM(-), (8) decreased the number of small DβH(+)/GAL(-) perikarya, (9) decreased the number of small and large perikarya expressing ER subtypes α and β and (10) decreased the total number of nerve fibers in the CaMG containing DβH and/or NPY and DβH and/or GAL. These results show that long-term E(2) treatment of adult gilts downregulates the populations of both noradrenergic and ERs expressing ovarian neurons in the CaMG. Our findings suggest also that elevated E(2) levels that occur during pathological states may regulate gonadal function(s) by affecting ovary supplying neurons.

Endometriosis-induced vaginal hyperalgesia in the rat: role of the ectopic growths and their innervation

Endometriosis is a painful disorder defined by extrauteral endometrial growths whose contribution to pain symptoms is poorly understood. Endometriosis is created in rats by autotransplanting on abdominal arteries pieces of either uterus (ENDO), which form cysts, or fat (shamENDO), which do not form cysts. ENDO, but not shamENDO induces vaginal hyperalgesia. We tested the hypothesis that the cysts are necessary to maintain vaginal hyperalgesia by assessing the effect of surgically removing them. Complete-cyst-removal eliminated ENDO-induced vaginal hyperalgesia up to 4 months post-operatively. Sham-cyst-removal in ENDO rats, in which cysts were not removed, or partial cyst-removal increased the ENDO-induced hyperalgesia. The decreases and increases both took 3-6 weeks to develop. Changes in ENDO-induced hyperalgesia did not occur in a control group of ENDO rats who had no surgery after ENDO. In a double-surgery control group, neither shamENDO surgery nor a subsequent sham surgery that mimicked "removal" of non-existent cysts influenced vaginal nociception. In a no-surgery control group, vaginal nociception remained stable for >6 months. The increases in ENDO-induced hyperalgesia produced by the sham-cyst-removal surgery were smaller in proestrus than in other estrous stages. During the other stages (but not during proestrus), sympathetic innervation of the cysts increased. These results suggest that maintenance of ENDO-induced vaginal hyperalgesia requires continued presence of at least some ectopic endometrial tissue, and that surgical treatment that fails to remove ectopic endometrial tissue can exacerbate the hyperalgesia, possibly due in part to an increase in the cysts' sympathetic innervation.

A unifying theory linking the prolonged efficacy of the stellate ganglion block for the treatment of chronic regional pain syndrome (CRPS), hot flashes, and posttraumatic stress disorder (PTSD)

The mechanism of action of the stellate ganglion block (SGB) is still uncertain; however it has been used successfully in treatment of chronic regional pain syndrome (CRPS) for many years. Our new insights in to the mechanism of action of the stellate ganglion block were first reported in 2007 in our publication detailing the control of hot flashes with the use of stellate ganglion blockade. We have demonstrated very significant results in the treatment of hot flashes and our most recent application of this block has been for the treatment of posttraumatic stress disorder (PTSD). Stellate ganglion has been demonstrated to have second and third order neurons connections with the central nervous system nuclei that modulate body temperature, neuropathic pain, the manifestations of PTSD, and many other areas. We believe that the commonality between the CRPS, HF and PTSD is the trigger of increased nerve growth factor (NGF) leading to the increase in brain norepinephrine (NR), which in turn is affected by the SGB leading to a prolonged reduction of NGF and eventually a decrease in NR. This, in turn, leads to a reduction or elimination of many of the symptoms of CRPS, Hot flashes, and PTSD.

Physiological concentration of 17beta-estradiol on sympathetic reinnervation in ovariectomized infarcted rats

17beta-Estradiol (E2) has been shown to exert antiarrhythmic effect after myocardial infarction; however, the mechanisms remain unclear. This study was performed to determine whether E2 exerts beneficial effects through attenuated sympathetic hyperreinnervation after infarction. Two weeks after ovariectomy, female Wistar rats were assigned to coronary artery ligation or sham operation. Twenty-four hours after coronary ligation, rats underwent one of five treatments: 1) sc vehicle treatment (control), 2) sc E2 treatment, 3) sc E2 treatment + tamoxifen (a potent estrogen receptor antagonist), 4) bosentan (an endothelin receptor blocker), or 5) sc E2 treatment + bosentan and followed for 4 wk. Myocardial endothelin-1 and norepinephrine levels at the remote zone revealed a significant elevation in control infarcted rats, compared with sham-operated rats, which is consistent with sympathetic hyperinnervation after infarction. Sympathetic hyperinnervation was blunted after giving the rats either E2 or bosentan, assessed by immunohistochemical analysis of tyrosine hydroxylase, growth-associated protein 43 and neurofilament, and Western blotting and real-time quantitative RT-PCR of nerve growth factor. Arrhythmic scores during programmed stimulation in E2-treated infarcted rats were significantly lower than in control-infarcted rats. Addition of bosentan did not have additional beneficial effects, compared with rats treated with E2 alone. The beneficial effect of E2 on sympathetic hyperinnervation was abolished by tamoxifen. Our data indicated that E2 has a role for sympathetic hyperinnervation after infarction, probably through an endothelin-1-depedent pathway. Chronic administration of E2 after infarction may attenuate the arrhythmogenic response to programmed electrical stimulation.