New effects of caffeine on corticotropin-releasing hormone (CRH)-induced stress along the intrafollicular classical hypothalamic-pituitary-adrenal (HPA) axis (CRH-R1/2, IP3 -R, ACTH, MC-R2) and the neurogenic non-HPA axis (substance P, p75NTR and TrkA) in ex vivo human male androgenetic scalp hair follicles

BACKGROUND

Human hair is highly responsive to stress, and human scalp hair follicles (HFs) contain a peripheral neuroendocrine equivalent of the systemic hypothalamic-pituitary-adrenal (HPA) stress axis. Androgenetic alopecia (AGA) is supposed to be aggravated by stress. We used corticotropin-releasing hormone (CRH), which triggers the HPA axis, to induce a stress response in human ex vivo male AGA HFs. Caffeine is known to reverse testosterone-mediated hair growth inhibition in the same hair organ culture model.

OBJECTIVES

To investigate whether caffeine would antagonize CRH-mediated stress in these HFs.

METHODS

HFs from balding vertex area scalp biopsies of men affected by AGA were incubated with CRH (10-7 mol L-1 ) with or without caffeine (0·001% or 0·005%).

RESULTS

Compared to controls, CRH significantly enhanced the expression of catagen-inducing transforming growth factor-β2 (TGF-β2) (P < 0·001), CRH receptors 1 and 2 (CRH-R1/2) (P < 0·01), adrenocorticotropic hormone (ACTH) (P < 0·001) and melanocortin receptor 2 (MC-R2) (P < 0·001), and additional stress-associated parameters, substance P and p75 neurotrophin receptor (p75NTR ). CRH inhibited matrix keratinocyte proliferation and expression of anagen-promoting insulin-like growth factor-1 (IGF-1) and the pro-proliferative nerve growth factor receptor NGF-tyrosine kinase receptor A (TrkA). Caffeine significantly counteracted all described stress effects and additionally enhanced inositol trisphosphate receptor (IP3 -R), for the first time detected in human HFs.

CONCLUSIONS

These findings provide the first evidence in ex vivo human AGA HFs that the stress mediator CRH induces not only a complex intrafollicular HPA response, but also a non-HPA-related stress response. Moreover, we show that these effects can be effectively antagonized by caffeine. Thus, these data strongly support the hypothesis that stress can impair human hair physiology and induce hair loss, and that caffeine may effectively counteract stress-induced hair damage and possibly prevent stress-induced hair loss.

Characterization of serotonin and N-acetylserotonin systems in the human epidermis and skin cells

Tryptophan hydroxylase (TPH) activity was detected in cultured epidermal melanocytes and dermal fibroblasts with respective Km of 5.08 and 2.83 mM and Vmax of 80.5 and 108.0 µmol/min. Low but detectable TPH activity was also seen in cultured epidermal keratinocytes. Serotonin and/or its metabolite and precursor to melatonin, N-acetylserotonin (NAS), were identified by LC/MS in human epidermis and serum. Endogenous epidermal levels were 113.18 ± 13.34 and 43.41 ± 12.45 ng/mg protein for serotonin (n = 8/8) and NAS (n = 10/13), respectively. Their production was independent of race, gender, and age. NAS was also detected in human serum (n = 13/13) at a concentration 2.44 ± 0.45 ng/mL, while corresponding serotonin levels were 295.33 ± 17.17 ng/mL (n = 13/13). While there were no differences in serum serotonin levels, serum NAS levels were slightly higher in females. Immunocytochemistry studies showed localization of serotonin to epidermal and follicular keratinocytes, eccrine glands, mast cells, and dermal fibrocytes. Endogenous production of serotonin in cultured melanocytes, keratinocytes, and dermal fibroblasts was modulated by UVB. In conclusion, serotonin and NAS are produced endogenously in the epidermal, dermal, and adnexal compartments of human skin and in cultured skin cells. NAS is also detectable in human serum. Both serotonin and NAS inhibited melanogenesis in human melanotic melanoma at concentrations of 10^-4 -10^-3  M. They also inhibited growth of melanocytes. Melanoma cells were resistant to NAS inhibition, while serotonin inhibited cell growth only at 10^-3  M. In summary, we characterized a serotonin-NAS system in human skin that is a part of local neuroendocrine system regulating skin homeostasis.

Novel interpenetrating polymer network provides significant and long-lasting improvements in hydration to the skin from different body areas

Background

Hydration and moisturization both impact skin quality, directly reflecting its appearance. Signs and onset of dehydration‐related skin aging are region‐specific and require tailored treatment to be effective.

Aims

To test the hydrating effects of formulas containing a novel 3‐dimensional 3‐polymer interpenetrating network (3D3P‐IPN) to deliver humectants and actives to specific body sites.

Methods

Two clinical studies were conducted focused on the skin under eyes and body (arms/legs). Healthy women ages 25‐65 (eyes) or 35‐65 (body) with mild to moderate dry and aged skin were enrolled. Study product containing the 3D3P‐IPN and tailored actives was applied twice daily for 8 weeks on the periorbital area and for 4 weeks on the body. Changes in skin attributes were measured by biophysical instrumentation for hydration, dark circles, skin color, elasticity and transepidermal water loss, and by clinical grading and subject self‐assessment.

Results

Significant improvements in hydration and skin smoothing were demonstrated in both studies. In the periorbital region, actives and humectants delivered by the 3D3P‐IPN also led to significant improvements in dark circles, fine lines/crow's feet, puffiness, restoring radiance, and overall younger‐looking appearance. On the arms and legs, there were significant reductions in crepiness and dullness. The arms and legs also had improvements in tactile and visual skin texture, radiance, and general healthy look. Improvements were immediate and persisted through the end of both studies.

Conclusion

The 3D3P‐IPN provides immediate and long‐lasting improvements in skin hydration and overall healthy appearance regardless of the targeted application site.

Effect of a Tranexamic Acid, Kojic Acid, and Niacinamide Containing Serum on Facial Dyschromia: A Clinical Evaluation

Background: Stubborn dyschromia such as melasma and post-inflammatory hyperpigmentation (PIH) are leading causes for cosmetic consultation. Topical treatment is challenging, using a range of modalities, to stop, hinder, and/or prevent steps in the pigment production process. Tranexamic acid (TXA), a potent plasmin inhibitor, is proposed to control pigmentation by inhibiting the release of inflammatory mediators involved in triggering melanogenesis. TXA has been recently introduced as a topical therapy aimed at reducing pigmentation in melasma. Methods: In a 12-week clinical study, a novel, topical facial serum containing 3% TXA, 1% kojic acid, and 5% niacinamide was evaluated for its effectiveness in treating melasma, PIH, and hyperpigmentation in Brazilian female subjects with Fitzpatrick skin types I-IV. Efficacy evaluations were performed at pre-treatment baseline, weeks 2, 4, 8, and 12, and included expert clinical grading, bio-instrumental measurements, and self-assessment questionnaires. Cutaneous tolerability was also evaluated by assessing subjective and objective irritation of the treatment area. Results: A significant improvement in the appearance of PIH, hyperpigmentation, melasma, skin texture, and skin tone homogeneity was observed beginning at week 2 and continued through week 12. Melanin index, as measured by Mexameter®, demonstrated a significant decrease by week 12 as compared to both pre-treatment baseline and control. Conclusions: The findings suggest that the test product is an effective and well-tolerated treatment option for addressing hyperpigmentary conditions, including melasma. Additional in vitro data suggests that TXA may act by mediating the inhibition of PGE2-stimulated human epidermal melanocytes. J Drugs Dermatol. 2019;18(5):454-459.

Melatonin and its derivatives counteract the ultraviolet B radiation-induced damage in human and porcine skin ex vivo

Melatonin and its derivatives (N¹ -acetyl-N² -formyl-5-methoxykynurenine [AFMK] and N-acetyl serotonin [NAS]) have broad-spectrum protective effects against photocarcinogenesis, including both direct and indirect antioxidative actions, regulation of apoptosis and DNA damage repair; these data were primarily derived from in vitro models. This study evaluates possible beneficial effects of melatonin and its active derivatives against ultraviolet B (UVB)-induced harm to human and porcine skin ex vivo and to cultured HaCaT cells. The topical application of melatonin, AFMK, or NAS protected epidermal cells against UVB-induced 8-OHdG formation and apoptosis with a further increase in p53^ser15 expression, especially after application of melatonin or AFMK but not after NAS use. The photoprotective action was observed in pre- and post-UVB treatment in both human and porcine models. Melatonin along with its derivatives upregulated also the expression of antioxidative enzymes after UVB radiation of HaCaT cells. The exogenous application of melatonin or its derivatives represents a potent and promising tool for preventing UVB-induced oxidative stress and DNA damage. This protection results in improved genomic, cellular, and tissue integrity against UVB-induced carcinogenesis, especially when applied prior to UV exposure. In addition, our ex vivo experiments provide fundamental justification for further testing the clinical utility of melatonin and metabolites as protectors again UVB in human subjects. Our ex vivo data constitute the bridge between vitro to vivo translation and thus justifies the pursue for further clinical utility of melatonin in maintaining skin homeostasis.

RORα and RORγ expression inversely correlates with human melanoma progression

The retinoic acid-related orphan receptors (RORs) regulate several physiological and pathological processes, including immune functions, development and cancer. To study the potential role of RORs in melanoma progression, we analysed RORα and RORγ expression in nevi and primary melanomas and non-lesional skin and metastases in relation to melanoma clinico-pathomorphological features. The expression of RORα and RORγ was lower in melanomas than in nevi and decreased during melanoma progression, with lowest levels found in primary melanomas at stages III and IV and in melanoma metastases. Their expression correlated with pathomorphological pTNM parameters being low in aggressive tumors and being high in tumors showing histological markers of good prognosis. Higher nuclear levels of RORα and RORγ and of cytoplasmic RORγ correlated with significantly longer overall and disease free survival time. Highly pigmented melanomas showed significantly lower level of nuclear RORs. This study shows that human melanoma development and aggressiveness is associated with decreased expression of RORα and RORγ, suggesting that RORs could be important in melanoma progression and host responses against the tumor. Furthermore, it suggests that RORα and RORγ might constitute a novel druggable target in anti-melanoma management using tumor suppressor gene therapy restoring their normal functions.

Effect of maternal high-fat diet on key components of the placental and hepatic endocannabinoid system

Maternal obesity in pregnancy has been linked to a spectrum of adverse developmental changes. Involvement of eCBs in obesity is well characterized. However, information regarding eCB physiology in obesity associated with pregnancy is sparse. This study evaluated fetomaternal hepatic, systemic, and placental eCB molecular changes in response to maternal consumption of a HFD. From ≥9 mo before conception, nonpregnant baboons ( Papio spp.) were fed a diet of either 45 (HFD; n = 11) or 12% fat or a control diet (CTR; n = 11), and dietary intervention continued through pregnancy. Maternal and fetal venous plasma samples were evaluated using liquid chromatography-mass spectrometry to quantify AEA and 2-AG. Placental, maternal and fetal hepatic tissues were analyzed using RT-PCR, Western blot, and immunohistochemistry. mRNA and protein expression of endocannabinoid receptors (CB1R and CB2R), FAAH, DAGL, MAGL, and COX-2 were determined. Statistical analyses were performed with the nonparametric Scheirer-Ray-Hare extension of the Kruskal-Wallis test to analyze the effects of diet (HFD vs. CTR), fetal sex (male vs. female), and the diet × sex interaction. Fetal weight was influenced by fetal sex but not by maternal diet. The increase in maternal weight in animals fed the HFD vs. the CTR diet approached significance ( P = 0.055). Maternal circulating 2-AG concentrations increased, and fetal circulating concentrations decreased in the HFD group, independently of fetal sex. CB1R receptor expression was detected in syncytiotrophoblasts (HFD) and the fetal endothelium (CTR and HFD). Placental CB2R protein expression was higher in males and lower in female fetuses in the HFD group. Fetal hepatic CB2R, FAAH, COX-2 (for both fetal sexes), and DAGLα (in male fetuses) protein expression decreased in the HFD group compared with the CTR group. We conclude that consumption of a HFD during pregnancy results in fetal systemic 2-AG and hepatic eCB deficiency.

On the role of classical and novel forms of vitamin D in melanoma progression and management

Melanoma represents a significant clinical problem affecting a large segment of the population with a relatively high incidence and mortality rate. Ultraviolet radiation (UVR) is an important etiological factor in malignant transformation of melanocytes and melanoma development. UVB, while being a full carcinogen in melanomagenesis, is also necessary for the cutaneous production of vitamin D3 (D3). Calcitriol (1,25(OH)2D3) and novel CYP11A1-derived hydroxyderivatives of D3 show anti-melanoma activities and protective properties against damage induced by UVB. The former activities include inhibitory effects on proliferation, plating efficiency and anchorage-independent growth of cultured human and rodent melanomas in vitro, as well as the in vivo inhibition of tumor growth by 20(OH)D3 after injection of human melanoma cells into immunodeficient mice. The literature indicates that low levels of 25(OH)D3 are associated with more advanced melanomas and reduced patient survivals, while single nucleotide polymorphisms of the vitamin D receptor or the D3 binding protein gene affect development or progression of melanoma, or disease outcome. An inverse correlation of VDR and CYP27B1 expression with melanoma progression has been found, with low or undetectable levels of these proteins being associated with poor disease outcomes. Unexpectedly, increased expression of CYP24A1 was associated with better melanoma prognosis. In addition, decreased expression of retinoic acid orphan receptors α and γ, which can also bind vitamin D3 hydroxyderivatives, showed positive association with melanoma progression and shorter disease-free and overall survival. Thus, inadequate levels of biologically active forms of D3 and disturbances in expression of the target receptors, or D3 activating or inactivating enzymes, can affect melanomagenesis and disease progression. We therefore propose that inclusion of vitamin D into melanoma management should be beneficial for patients, at least as an adjuvant approach. The presence of multiple hydroxyderivatives of D3 in skin that show anti-melanoma activity in experimental models and which may act on alternative receptors, will be a future consideration when planning which forms of vitamin D to use for melanoma therapy.

Noncalcemic 20-hydroxyvitamin D3 inhibits human melanoma growth in in vitro and in vivo models

A novel pathway of vitamin D₃ (D₃) metabolism, initiated by C20-hydroxylation of D₃ by CYP11A1, has been confirmed to operate in vivo. Its major product, 20(OH)D₃, exhibits antiproliferative activity in vitro comparable to that of 1,25(OH)₂D₃, but is noncalcemic in mice and rats. To further characterize the antimelanoma activity of 20(OH)D₃, we tested its effect on colony formation of human melanoma cells in monolayer culture and anchorage-independent growth in soft agar. The migratory capabilities of the cells and cell-cell and cell-extracellular matrix interactions were also evaluated using transwell cell migration and spheroid toxicity assays. To assess the antimelanoma activity of 20(OH)D₃in vivo, age-matched immunocompromised mice were subcutaneously implanted with luciferase-labelled SKMel-188 cells and were randomly assigned to be treated with either 20(OH)D₃ or vehicle (n=10 per group). Tumor size was measured with caliper and live bioimaging methods, and overall health condition expressed as a total body score scale. The following results were observed: (i) 20(OH)D₃ inhibited colony formation both in monolayer and soft agar conditions, (ii) 20(OH)D₃ inhibited melanoma cells in both transwell migration and spheroid toxicity assays, and (iii) 20(OH)D₃ inhibited melanoma tumor growth in immunocompromised mice without visible signs of toxicity. However, although the survival rate was 90% in both groups, the total body score was higher in the treatment group compared to control group (2.8 vs. 2.55). In conclusion, 20(OH)D₃, an endogenously produced secosteroid, is an excellent candidate for further preclinical testing as an antimelanoma agent.

Skin Exposure to Ultraviolet B Rapidly Activates Systemic Neuroendocrine and Immunosuppressive Responses

The back skin of C57BL/6 mice was exposed to a single 400 mJ cm^-2 dose of ultraviolet B (UVB), and parameters of hypothalamic-pituitary-adrenal (HPA) axis in relation to immune activity were tested after 30-90 min following irradiation. Levels of brain and/or plasma corticotropin-releasing hormone (CRH), β-endorphin, ACTH and corticosterone (CORT) were enhanced by UVB. Hypophysectomy had no effect on UVB-induced increases of CORT. Mitogen-induced IFNγ production by splenocytes from UVB-treated mice was inhibited at 30, 90 min and after 24 h. UVB also led to inhibition of IL-10 production indicating an immunosuppressive effect on both Th1 and Th2 cytokines. Conditioned media from splenocytes isolated from UVB-treated animals had no effect on IFNγ production in cultured normal splenocytes; however, IFNγ increased with conditioned media from sham-irradiated animals. Sera from UVB-treated mice suppressed T-cell mitogen-induced IFNγ production as compared to sera from sham-treated mice. IFNγ production was inhibited in splenocytes isolated from UVB-treated animals with intact pituitary, while stimulated in splenocytes from UVB-treated hypophysectomized mice. Thus, cutaneous exposure to UVB rapidly stimulates systemic CRH, ACTH, β-endorphin and CORT production accompanied by rapid immunosuppressive effects in splenocytes that appear to be independent of the HPA axis.

Ultraviolet B stimulates proopiomelanocortin signalling in the arcuate nucleus of the hypothalamus in mice

We previously found that ultraviolet B (UVB) could stimulate the paraventricular nucleus (PVN) with activation the systemic hypothalamic-pituitary- adrenal (HPA) axis. To investigate whether UVB can also stimulate other hypothalamic nuclei, we tested its effect on the proopiomelanocortin (POMC) related signalling system in the arcuate nucleus (ARC) of female C57BL/6 and FVB albino mice. The shaved back skin of the mice was irradiated with either 100 or 400 mJ/cm2 of UVB. After 1, 3, 6 and 12 h, blood and hypothalamus were collected and processed for gene and protein expression, and measurement of α-MSH and β-endorphin (β-END) levels. An in situ immunohistochemical examination was performed for melanocortin receptor 4 (MC4R) and POMC-derived α-MSH. The expression of Pomc and MC4R mRNAs was stimulated, whereas that of AgRP was inhibited after exposure to UVB. It was accompanied by an increased number of both α-MSH- and MC4R-immunoreactive neurons in the ARC, and by increased levels of α-MSH and β-END (both found in the hypothalamus and plasma). This surprising discovery of UVB stimulating the POMC system in the ARC, accompanied by the increased plasma levels of α-MSH and β-END, paves the way for exciting areas of research on the communication between the skin and the brain, as well as is suggesting a new role for UVB in regulation of body metabolism.

Assessment of the Tumorigenic Potential of Spontaneously Immortalized and hTERT-Immortalized Cultured Dental Pulp Stem Cells

Dental pulp stem cells (DPSCs) provide an exciting new avenue to study neurogenetic disorders. DPSCs are neural crest-derived cells with the ability to differentiate into numerous tissues including neurons. The therapeutic potential of stem cell-derived lines exposed to culturing ex vivo before reintroduction into patients could be limited if the cultured cells acquired tumorigenic potential. We tested whether DPSCs that spontaneously immortalized in culture acquired features of transformed cells. We analyzed immortalized DPSCs for anchorage-independent growth, genomic instability, and ability to differentiate into neurons. Finally, we tested both spontaneously immortalized and human telomerase reverse transcriptase (hTERT)-immortalized DPSC lines for the ability to form tumors in immunocompromised animals. Although we observed increased colony-forming potential in soft agar for the spontaneously immortalized and hTERT-immortalized DPSC lines relative to low-passage DPSC, no tumors were detected from any of the DPSC lines tested. We noticed some genomic instability in hTERT-immortalized DPSCs but not in the spontaneously immortalized lines tested. We determined that immortalized DPSC lines generated in our laboratory, whether spontaneously or induced, have not acquired the potential to form tumors in mice. These data suggest cultured DPSC lines that can be differentiated into neurons may be safe for future in vivo therapy for neurobiological diseases.

The role of melanogenesis in regulation of melanoma behavior: melanogenesis leads to stimulation of HIF-1α expression and HIF-dependent attendant pathways

To study the effect of melanogenesis on HIF-1α expression and attendant pathways, we used stable human and hamster melanoma cell lines in which the amelanotic vs. melanotic phenotypes are dependent upon the concentration of melanogenesis precursors in the culture media. The induction of melanin pigmentation led to significant up-regulation of HIF-1α, but not HIF-2α, protein in melanized cells for both lines. Similar upregulation of nuclear HIF-1α was observed in excisions of advanced melanotic vs. amelanotic melanomas. In cultured cells, melanogenesis also significantly stimulated expression of classical HIF-1-dependent target genes involved in angiogenesis and cellular metabolism, including glucose metabolism and stimulation of activity of key enzymes in the glycolytic pathway. Several other stress related genes containing putative HRE consensus sites were also upregulated by melanogenesis, concurrently with modulation of expression of HIF-1-independent genes encoding for steroidogenic enzymes, cytokines and growth factors. Immunohistochemical studies using a large panel of pigmented lesions revealed that higher levels of HIF-1α and GLUT-1 were detected in advanced melanomas in comparison to melanocytic nevi or thin melanomas localized to the skin. However, the effects on overall or disease free survival in melanoma patients were modest or absent for GLUT-1 or for HIF-1α, respectively. In conclusion, induction of the melanogenic pathway leads to robust upregulation of HIF-1-dependent and independent pathways in cultured melanoma cells, suggesting a key role for melanogenesis in regulation of cellular metabolism.

UVB Activates Hypothalamic-Pituitary-Adrenal Axis in C57BL/6 Mice

To test the hypothesis that ultraviolet B (UVB) can activate the hypothalamic-pituitary-adrenal (HPA) axis, the shaved back skin of C57BL/6 mice was exposed to 400 mJ/cm² of UVB or was shame irradiated. After 12 and 24 h of exposure, plasma, skin, brain, and adrenals were collected and processed to measure corticotropin-releasing hormone (CRH), urocortin (Ucn), β-endorphin (β-END), ACTH and corticosterone (CORT) or brain was fixed for immunohistochemical detection of CRH. UVB stimulated plasma levels of CRH, Ucn, β-END, ACTH and CORT, and increased skin expression of Ucn, β-END and CORT at the gene and protein/peptide levels. UVB stimulated CRH gene and protein expression in the brain that was localized to the paraventricular nucleus of the hypothalamus. In adrenal glands it increased mRNAs of melanocortin receptor type 2, StAR and CYP11B1. Hypophysectomy abolished UVB stimulation of plasma but not of skin CORT levels, and had no effect on UVB stimulation of CRH and Ucn levels in the plasma, demonstrating the requirement of an intact pituitary for the systemic effect. In conclusion, we identify mechanism of the regulation of body homeostasis by UVB through activation of the HPA axis that originates in the skin and requires pituitary for the systemic effect.

RORα and ROR γ are expressed in human skin and serve as receptors for endogenously produced noncalcemic 20-hydroxy- and 20,23-dihydroxyvitamin D

RORα and RORγ are expressed in human skin cells that produce the noncalcemic 20-hydroxyvitamin D3 [20(OH)D3] and 20,23-dihydroxyvitamin D3 [20,23(OH)2D3]. Chinese hamster ovary (CHO) cells stably expressing a Tet-on RORα or RORγ expression vector and a ROR-responsive element (RORE)-LUC reporter, and a mammalian 2-hybrid model examining the interaction between the ligand binding domain (LBD) of RORα or RORγ with an LBD-interacting LXXLL-peptide, were used to study ROR-antagonist activities. These assays revealed that 20(OH)D3 and 20,23(OH)2D3 function as antagonists of RORα and RORγ. Moreover, 20(OH)D3 inhibited the activation of the promoter of the Bmal1 and G6pase genes, targets of RORα, and 20(OH)D3 and 20,23(OH)2D3 inhibited Il17 promoter activity in Jurkat cells overexpressing RORα or RORγ. Molecular modeling using crystal structures of the LBDs of RORα and RORγ revealed docking scores for 20(OH)D3, 20,23(OH)2D3 and 1,25(OH)2D3 similar to those of the natural ligands, predicting good binding to the receptor. Notably, 20(OH)D3, 20,23(OH)2D3, and 1,25(OH)2D3 inhibited RORE-mediated activation of a reporter in keratinocytes and melanoma cells and inhibited IL-17 production by immune cells. Our study identifies a novel signaling pathway, in which 20(OH)D3 and 20,23(OH)2D3 act as antagonists or inverse agonists of RORα and RORγ, that opens new possibilities for local (skin) or systemic regulation.-Slominski, A. T., Kim, T.-K., Takeda, Y., Janjetovic, Z., Broz˙yna, A. A., Skobowiat, C., Wang, J., Postlethwaite, A., Li, W., Tuckey, R. C., Jetten, A. M. RORα and ROR γ are expressed in human skin and serve as receptors for endogenously produced noncalcemic 20-hydroxy- and 20,23-dihydroxyvitamin D.

Genetic variation of the cutaneous HPA axis: an analysis of UVB-induced differential responses

Mammalian skin incorporates a local equivalent of the hypothalamic-pituitary-adrenal (HPA) axis that is critical in coordinating homeostatic responses against external noxious stimuli. Ultraviolet radiation B (UVB) is a skin-specific stressor that can activate this cutaneous HPA axis. Since C57BL/6 (B6) and DBA/2J (D2) strains of mice have different predispositions to sensorineural pathway activation, we quantified expression of HPA axis components at the gene and protein levels in skin incubated ex vivo after UVB or sham irradiation. Urocortin mRNA was up-regulated after all doses of UVB with a maximum level at 50 mJ/cm(2) after 12h for D2 and at 200 mJ/cm(2) after 24h for B6. Proopiomelanocortin mRNA was enhanced after 6h with the peak after 12h and at 200 mJ/cm(2) for both genotypes of mice. ACTH levels in tissue and media increased after 24h in B6 but not in D2. UVB stimulated β-endorphin expression was higher in D2 than in B6. Melanocortin receptor 2 mRNA was stimulated by UVB in a dose-dependent manner, with a peak at 200 mJ/cm(2) after 12h for both strains. The expression of Cyp11a1 mRNA - a key mitochondrial P450 enzyme in steroidogenesis, was stimulated at all doses of UVB irradiation, with the most pronounced effect after 12-24h. UVB radiation caused, independently of genotype, a dose-dependent increase in corticosterone production in the skin, mainly after 24h of histoculture. Thus, basal and UVB stimulated expression of the cutaneous HPA axis differs as a function of genotype: D2 responds to UVB earlier and with higher amplitude than B6, while B6 shows prolonged (up to 48 h) stress response to a noxious stimulus such as UVB.

Commentary on the practical guide for the study of sebaceous glands

For many years, the function of the sebaceous gland (SG) was underestimated and suggested by Albert M. Kligman as a remnant of human development, a 'living fossil with a past but no future'. However, the last two decades of studies and the discovery of neuro-endocrine pathways in skin have determined the importance of the SG in cutaneous biology and homeostasis. SGs play their role in cutaneous homeostasis by contribution to local steroidogenic pathways, antimicrobial activity and display of immune (both pro- and anti-inflammatory) properties. Despite several important manuscripts and reviews regarding SG biology and function, there was an urgent need for a high-quality methodological guide through SG identification and quantitative evaluation. In this issue of Experimental Dermatology, Hinde et al. present a practical guide to SG research - outlining methods, defining immunohistochemical markers and providing guidance to both novice and more experienced SG researchers.

Endocannabinoid crosstalk between placenta and maternal fat in a baboon model (Papio spp.) of obesity

INTRODUCTION

Maternal obesity (MO) remains a serious obstetric problem with acute and chronic morbidities for both mothers and offspring. The mechanisms underlying these adverse consequences of MO remain unknown. Endocannabinoids (ECB) are neuromodulatory lipids released from adipocytes and other tissues. Metabolic crosstalk between placenta and adipocytes may mediate sequelae of MO. The goal of this study was to elucidate placental and systemic ECB in MO.

MATERIAL AND METHODS

Placentas, sera, and subcutaneous fat were collected at Cesarean sections performed near term (0.9 G) in four non-obese (nOB) and four obese (OB) baboons (Papio spp.). Concentrations of anandamide (AEA) and 2-arachidonoylglycerol (2-AG) were measured by liquid chromatography coupled to tandem mass spectrometry. AEA and 2-AG pathways were characterized in placentas by Q-RT-PCR, Western blot and immunohistochemistry.

RESULTS

Placental 2-AG levels were lower and maternal fat AEA levels were higher in OB (1254.1 ± 401.3 nmol/kg and 17.3 ± 4 nmol/kg) vs. nOB (3124.2 ± 557.3 nmol/kg and 3.1 ± 0.6 nmol/kg) animals. Concentrations of 2-AG correlated positively between maternal fat and placenta (r = 0.82, p = 0.013), but correlated negatively with maternal leptin concentrations (r = -0.72, p = 0.04 and r = -0.83, p = 0.01, respectively).

CONCLUSION

This is the first study to demonstrate differential ECB pathway regulation in maternal fat and placenta in MO. Differential regulation and function exist for AEA and 2-AG as the major ECB pathways in placenta.

Steroidogenesis in the skin: implications for local immune functions

The skin has developed a hierarchy of systems that encompasses the skin immune and local steroidogenic activities in order to protect the body against the external environment and biological factors and to maintain local homeostasis. Most recently it has been established that skin cells contain the entire biochemical apparatus necessary for production of glucocorticoids, androgens and estrogens either from precursors of systemic origin or, alternatively, through the conversion of cholesterol to pregnenolone and its subsequent transformation to biologically active steroids. Examples of these products are corticosterone, cortisol, testosterone, dihydrotesterone and estradiol. Their local production can be regulated by locally produced corticotropin releasing hormone (CRH), adrenocorticotropic hormone (ACTH) or cytokines. Furthermore the production of glucocorticoids is affected by ultraviolet B radiation. The level of production and nature of the final steroid products are dependent on the cell type or cutaneous compartment, e.g., epidermis, dermis, adnexal structures or adipose tissue. Locally produced glucocorticoids, androgens and estrogens affect functions of the epidermis and adnexal structures as well as local immune activity. Malfunction of these steroidogenic activities can lead to inflammatory disorders or autoimmune diseases. The cutaneous steroidogenic system can also have systemic effects, which are emphasized by significant skin contribution to circulating androgens and/or estrogens. Furthermore, local activity of CYP11A1 can produce novel 7Δ-steroids and secosteroids that are biologically active. Therefore, modulation of local steroidogenic activity may serve as a new therapeutic approach for treatment of inflammatory disorders, autoimmune processes or other skin disorders. In conclusion, the skin can be defined as an independent steroidogenic organ, whose activity can affect its functions and the development of local or systemic inflammatory or autoimmune diseases. This article is part of a Special Issue entitled 'CSR 2013'.

Ultraviolet radiation regulates cortisol activity in a waveband-dependent manner in human skin ex vivo

BACKGROUND

11β-Hydroxysteroid dehydrogenase type 1 (11β-HSD1), 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2), and glucocorticoids (GC) and their receptor (GR) play a key role in tissue-specific regulation of GC action.

OBJECTIVES

To determine the expression of genes encoding 11β-HSD1 (HSD11B1), 11β-HSD2 (HSD11B2) and GR (GRα; also known as NC3R1) and their protein products, and levels of cortisol in human skin explants and/or cocultured keratinocytes/melanocytes after treatment with ultraviolet (UV) A, B or C wavebands.

METHODS

Skin from foreskins and/or cocultured human keratinocytes/melanocytes were irradiated with UVA, UVB or UVC (skin) and incubated for 12 and 24 h. Methods of reverse transcription-polymerase chain reaction, Western blotting, enzyme-linked immunosorbent assay and immunohistochemistry (IHC) were used to determine expression and localization of corresponding genes or antigens.

RESULTS

UVB enhanced the HSD11B1 gene and protein expression in a dose-dependent manner, while UVA had no effect. Similarly, UVC increased 11β-HSD1 protein product as measured by IHC. UVB and UVC enhanced cortisol production and decreased epidermal GR expression, while UVA had no detectable effects. Although both UVA and UVB stimulated HSD11B2 gene expression, only UVA increased 11β-HSD2 protein product levels with UVB and UVC having no effect.

CONCLUSIONS

We suggest that these differential, waveband-dependent effects of UV radiation on the expression of cutaneous HSD11B1, HSD11B2 and GRα genes and their corresponding protein products, and cortisol production are to protect and/or restore the epidermal barrier homeostasis against disruption caused by the elevated cortisol level induced by UVB and UVC.

Sensing the environment: regulation of local and global homeostasis by the skin's neuroendocrine system

Skin, the body's largest organ, is strategically located at the interface with the external environment where it detects, integrates, and responds to a diverse range of stressors including solar radiation. It has already been established that the skin is an important peripheral neuro-endocrine-immune organ that is tightly networked to central regulatory systems. These capabilities contribute to the maintenance of peripheral homeostasis. Specifically, epidermal and dermal cells produce and respond to classical stress neurotransmitters, neuropeptides, and hormones. Such production is stimulated by ultraviolet radiation (UVR), biological factors (infectious and noninfectious), and other physical and chemical agents. Examples of local biologically active products are cytokines, biogenic amines (catecholamines, histamine, serotonin, and N-acetyl-serotonin), melatonin, acetylocholine, neuropeptides including pituitary (proopiomelanocortin-derived ACTH, beta-endorphin or MSH peptides, thyroid-stimulating hormone) and hypothalamic (corticotropin-releasing factor and related urocortins, thyroid-releasing hormone) hormones as well as enkephalins and dynorphins, thyroid hormones, steroids (glucocorticoids, mineralocorticoids, sex hormones, 7-delta steroids), secosteroids, opioids, and endocannabinoids. The production of these molecules is hierarchical, organized along the algorithms of classical neuroendocrine axes such as hypothalamic-pituitary-adrenal axis (HPA), hypothalamic-thyroid axis (HPT), serotoninergic, melatoninergic, catecholaminergic, cholinergic, steroid/secosteroidogenic, opioid, and endocannbinoid systems. Dysregulation of these axes or of communication between them may lead to skin and/ or systemic diseases. These local neuroendocrine networks are also addressed at restricting maximally the effect of noxious environmental agents to preserve local and consequently global homeostasis. Moreover, the skin-derived factors/systems can also activate cutaneous nerve endings to alert the brain on changes in the epidermal or dermal environments, or alternatively to activate other coordinating centers by direct (spinal cord) neurotransmission without brain involvement. Furthermore, rapid and reciprocal communications between epidermal and dermal and adnexal compartments are also mediated by neurotransmission including antidromic modes of conduction. In conclusion, skin cells and skin as an organ coordinate and/or regulate not only peripheral but also global homeostasis.

Cutaneous hypothalamic-pituitary-adrenal axis homolog: regulation by ultraviolet radiation

The hypothalamic-pituitary-adrenal (HPA) axis maintains basal and stress-related homeostasis in vertebrates. Skin expresses all elements of the HPA axis including corticotropin-releasing hormone (CRH), proopiomelanocortin (POMC), ACTH, β-endorphin (β-END) with corresponding receptors, the glucocorticoidogenic pathway, and the glucocorticoid receptor (GR). To test the hypothesis that cutaneous responses to environmental stressors follow the organizational structure of the central response to stress, the activity of the "cutaneous HPA" axis homolog was investigated after exposure to ultraviolet radiation (UVR) wavelengths of UVA (320-400 nm), UVB (280-320 nm), and UVC (100-280 nm) in human skin organ culture and in co-cultured keratinocytes/melanocytes. The level of stimulation of CRH, POMC, MC1R, MC2R, CYP11A1, and CYP11B1 genes was dependent on UV wavelengths and doses, with the highest effects observed for highly energetic UVC and UVB. ELISA and Western assays showed significant production of CRH, POMC, ACTH, and CYP11A1 proteins and of cortisol, with a decrease in GR expression only after UVB and UVC. However, β-END expression was also stimulated by UVA. Immunocytochemistry localized the deposition of the aforesaid antigens predominantly to the epidermis with additional accumulation of CRH, β-END, and ACTH in the dermis. UVR-stimulated CYP11A1 expression was seen in the basal layer of the epidermis and cells of adjacent dermis. Thus, the capacity to activate or change the spatial distribution of the cutaneous HPA axis elements is dependent on highly energetic wavelengths (UVC and UVB), implying a dependence of a local stress response on their noxious activity with overlapping or alternative mechanisms activated by UVA.

Axotomy induced changes in neuronal plasticity of sympathetic chain ganglia (SChG) neurons supplying descending colon in the pig

Sympathetic neurons are capable of extensive regeneration following axonal injury. To investigate the response to axotomy of colon-projecting neurons (CPN) localized in the porcine sympathetic chain ganglia (SChG), the retrograde Fast Blue (FB) tracer, axonal transection and double immunohistochemistry methods were applied. The CPN were localized exclusively in the lumbar SChG and displayed a predominantly catecholaminergic [i.e. Tyrosine Hydroxylase (TH)/Dopamine β Hydroxylase (DβH)] and Neuropeptide Y (NPY) positive phenotype under physiological conditions. Axotomy led to a significant decrease in TH/DβH production and a simultaneous increase in the neuropeptides Galanin (GAL) and Somatostatin (SOM), but not NPY or Vasoactive Intestinal Peptide (VIP) expression in retrogradely traced perikarya. Furthermore, the decrease in density of TH-/DβH-, VIP-, Leu(5)-Enkephalin (LENK)-, Choline Acetyltransferase (ChAT)-immunoreactive (-IR) nerve fibers occurred after axotomy. These data suggest a species-specific response to axonal damage of the CPN localized in porcine SChG. Since the SChG neurons supervise the vasculature of gut both in physiological and pathological conditions, and since pig is a more accurate animal model of human gut than a rodent (Swindle et al., 1992), these data may contribute to the understanding of the pathology of several gut illnesses, like Crohn Disease and Irritable Bowel Syndrome which commonly affect western populations.

Distribution and chemical coding of sympathetic neurons in the caudal mesenteric ganglion projecting to the ovary in sexually mature gilts

The distribution and co-localisation patterns of dopamine-beta-hydroxylase (DβH), neuropeptide Y (NPY), somatostatin (SOM) and galanin (GAL) were investigated by use of retrograde neuronal tracing and double-labelling immunofluorescence techniques in the caudal mesenteric ganglion (CaMG) neurons supplying the ovary of adult pigs. The existence and density of nerve fibres that are immunoreactive (IR) for the above-mentioned neuroactive substances were also evaluated. Injections of a fluorescent tracer (Fast Blue; FB) into the ovaries revealed the presence of small- (76.38%) and large-sized (23.62%) FB-positive postganglionic neurons in the CaMG. Noradrenergic FB-positive cells were simultaneously NPY- (43.38%), SOM- (18.77%) and GAL- (18.31%) IR. Of the examined FB-positive neurons, 53.49% were DβH-IR but NPY-immunonegative (IN), 79.06% were DβH-IR but SOM-IN, and 77.16% were DβH-IR but GAL-IN. Small- or large-sized subsets of traced neurons were supplied by only one or a few nerve fibres, exhibiting DβH-, NPY-, SOM- and/or GAL-IR. Our data show the specific morphological as well as immunochemical structural organisation of the sympathetic neurons in the CaMG in adult gilts. The occurrence of an abundant population of noradrenergic perikarya in the CaMG may suggest their important physiological role in the regulation of gonadal function(s) in these animals.

Distribution pattern and chemical coding of neurons of the sympathetic chain ganglia supplying the descending colon in the pig

Sympathetic chain ganglia (SChG) neurons projecting to the descending colon of the pig were studied by means of retrograde tracing (Fast Blue, FB) and double-labelling immunofluorescence methods. FB was injected into the gut wall and after three weeks survival time the animals were transcardially perfused with paraformaldehyde and the bilateral sympathetic trunks were collected. The FB-positive neurons were localised only in the lumbar (L(1)-L(5)) ganglia of the sympathetic trunk and appeared either as small (30-50 microm in diameter) round-shaped perikarya forming clusters localised in caudal-ventral area or, rarely, as bigger (50-80 microm) and dispersed solitary irregular perikarya. Immunohistochemical staining revealed the catecholaminergic (tyrosine hydroxylase-/dopamine beta-hydroxylase-immunoreactive) character of the great majority of FB-positive neurons which preferentially co-expressed neuropeptide Y. In addition, none of the FB-positive perikarya was immunopositive to galanin, somatostatin, choline acetyltransferase, vasoactive intestinal peptide, pituitary adenylate cyclase-activating peptide, leu(5)-enkephalin, nitric oxide synthase, substance P and calcitonin-generelated peptide.

Phenotyping of sympathetic chain ganglia (SChG) neurons in porcine colitis

Colonic inflammation involves the changes in chemical coding of not only sensory but also enteric and sympathetic prevertebral neurons innervating inflamed target tissue. Since the sympathetic chain ganglia neurons (SChG) affect colonic function, the purpose of our study was to determine the precise location of the SChG neurons innervating the porcine descending colon, define their chemical coding and answer the question of whether paraformaldehyde-induced colitis in female pigs is able to change the chemical phenotype of the perikarya. Using the Fast Blue (FB) retrograde tracing, the greatest concentration of the (FB+) perikarya was revealed in L₃ ganglia. Applying double immunohistochemistry, we detected a strongly catecholaminergic character and in majority neuropeptide Y (NPY)-positive staining of the colon-projecting FB+ neurons both in the control and the inflamed animals. Furthermore, colonic inflammation caused the significant increase in density of galanin- (P<0.001), somatostatin- (P<0.005), leu5-enkephalin- (P<0.05), substance P- (P<0.005), and calcitonin gene-related peptide- (P<0.005) immunoreactive (-IR) nerve fibers surrounding the FB+ perikarya, while the density of nitric oxide synthase-IR and NPY-IR fibers remained unaffected compared to the control animals. The increase in visible immunofluorescent detection of neuropeptide-containing fibers could possibly be caused by enhanced demand and release of neuropeptides that modulate intestinal immune response and regulate the gastrointestinal activity through inflammatory mediators.

Inflammation- and axotomy-induced changes in galanin-like immunoreactive (GAL-LI) nerve structures in the porcine descending colon

This study reports on changes caused by chemically driven inflammation and axotomy in galanin-like immunoreactive (GAL-LI) nerve structures in the porcine descending colon. The distribution pattern of GAL-LI structures was studied using the immunofluorescence technique in the circular muscle layer, the myenteric (MP), outer submucous (OSP) and inner submucous plexuses (ISP), and also in the mucosal layer. Under physiological conditions GAL-LI perikarya were shown to constitute 3.68 +/- 0.32%, 7.02 +/- 0.93% and 10.99 +/- 0.71% in MP, OSP and ISP, respectively. Both colitis and axotomy caused an increase in GAL-like immunoreactivity, which was different in particular parts of the bowel segment studied. The numbers of GAL-LI perikarya increased to 14.16 +/- 0.49%, 16.78 +/- 1.09% and 37.46 +/- 1.18% during colitis and 7.92 +/- 0.72%, 10.44 +/- 0.71% and 16.20 +/- 0.96% after axotomy in MP, OSP and ISP, respectively. Both these processes caused an increase in the number of GAL-LI nerve fibres in the circular muscle and mucosal layers as well as the appearance of a population of GAL-LI cells in the mucosa.

Analysis of the chemical coding of neurons in the intermediate thoracic ganglion of the pig

The pig has been widely used as a model in cardiovascular research. A unique feature of the porcine extrinsic sympathetic cardiac nerves is that they arise from intermediate ganglia in the thoracic cavity. The localization and pattern of distribution of nerve cell bodies and fibers containing tyrosine hydroxylase (TH), dopamine B-hydroxylase (DBH), neuropeptide Y (NPY), vasoactive intestinal polypeptide (VIP), somatostatin (SOM), galanin (GAL), methionine-enkephalin (MET) as well as calcitonin gene-related peptide (CGRP), substance P (SP) and pituitary adenylate cyclase-activating peptide (PACAP) was studied with immunohistochemistry. Almost all the neurons showed immunoreactivity to TH. Immunoreactivity to NPY, VIP, SOM, GAL, MET and PACAP was displayed by nerve cell bodies while nerve fibers exhibited immunoreactivity to all the neuropeptides studied. Therefore, it seems that the chemical coding of neurons and especially nerve fibers in the porcine intermediate ganglion share general similarities (with certain neurochemical variability), with porcine prevertebral ganglia (e.g., celiacomesenteric and caudal mesenteric ganglia).

Distribution of cocaine- and amphetamine-regulated transcript-like immunoreactive (CART-LI) nerve structures in the porcine large intestine

The aim of the present study was to investigate the number of cocaine- and amphetamine-regulated transcript-like immunoreactive (CART-LI) nerve structures in the large intestine of juvenile pigs. The distribution pattern of CART-LI structures was studied by immunohistochemistry in the circular muscle layer, myenteric (MP), outer submucous (OSP) and inner submucous plexus (ISP) as well as in the mucosal layer of six regions of the large bowel: caecum, centripetal and centrifugal turns of the proximal colon, transverse colon, descending colon and rectum. CART-LI neural structures were observed in all gut fragments studied. CART-LI nerve fibres were numerous within the circular muscle layer and in the MP of all the regions studied, while they were moderate or few in number in other layers of the intestinal wall. The numbers of CART-LI neurons within the MP amounted to 2.02% in the caecum to 7.92% in the rectum, within the OSP from 2.73% in the centrifugal turns of the proximal colon to 5.70% in the rectum, and within the ISP from 2.23% in the transverse colon to 5.32% in the centrifugal turns of the proximal colon. The present study reports for the first time a detailed description of the CART distribution pattern within the enteric nervous system (ENS) of the porcine large intestine.

The relationship and co-localization of vasoactive intestinal peptide (VIP)- and Leu5-enkephalin (LENK)-immunoreactivity in the female genital tract of the pig

The vasoactive intestinal peptide (VIP) and opioid family member Leu5-enkephalin (LENK) have already been established as playing independently significant roles in the functioning of the female genital tract. However, the mutual influence of both neuropeptides on female genital function has not been examined until now. Therefore, the aim of this study was to compare the distribution of VIP- and/or LENK-immunoreactive (IR) structures throughout the female genital tract of the pig. Immunohistochemical examination revealed that the great majority of the immunopositive structures co-expressed both peptides. Nevertheless, a small population of exclusively VIP- or LENK-IR processes and perikarya were also distinguished. The muscular layer of the organs examined revealed the greatest density of VIP- and/or LENK-IR nerve fibers. The mucosa of the ampulla, isthmus, cervix and vagina was supplied with a moderate number of single labeled LENK-IR processes, while exclusively VIP-IR fibers were found mainly in vaginal mucosa. The infundibulum was found to be poorly supplied with single labeled VIP- or LENK-IR fibers. The paracervical ganglion (PCG), the expected source of VIP- and/or LENK-IR nerve fibers innervating the organs under investigation, has been found to contain double labeled LENK-/VIP-IR as well as single labeled VIP-IR perikarya. The great number of specific co-localization between VIP and LENK in nerve processes of the porcine female genital organs may indicate a functional regulatory interaction between the neuropeptides studied, requiring further study.

Immunodetection of cocaine- and amphetamine-regulated transcript in the rumen, reticulum, omasum and abomasum of the sheep

Enteric nerves harbour a wide array of neuropeptides playing a key role in the regulation of gastrointestinal tract functions. In this study, the distribution patterns of cocaine- and amphetamine-regulated transcript-immunoreactive (CART-IR) nerve fibres as well as the percentages of CART-positive enteric neurons were immunohistochemically assessed in the rumen, reticulum, omasum and abomasum of the sheep. Double staining were applied, to elucidate whether neuropeptide Y (NPY), vasoactive intestinal polypeptide (VIP), substance P (SP), somatostatin or serotonin co-exist in CART-IR gastric structures. In the rumen, reticulum, omasum and abomasum, a majority of myenteric neurons identified by immunoreactivity to Hu C/D were CART-positive (47.1 +/- 3.6%, 45.1 +/- 3.0%, 41.6 +/- 2.6% and 40.9 +/- 2.9% respectively). The smooth musculature of the forestomachs as well as abomasum was innervated with numerous CART-IR nerve fibres. Blood vessels-associated CART-positive nerve terminals were identified in the submucosa of the reticulum only. Lamina muscularis mucosae of the omasum and abomasum was moderately innervated with CART-IR nerve terminals. In the abomasum sparse CART-IR nerve fibres were seen between mucosal glands. A small population of endocrine cells of the abomasum also exhibited the presence of CART. All neuronal elements as well as endocrine cells IR to CART were negative to somatostatin and/or serotonin. No immunoreactivity to VIP, NPY and/or SP was found in myenteric ganglia-projecting CART-positive nerve fibres. The co-localization of CART with VIP, NPY and/or SP was regularly observed in myenteric neurons as well as the smooth muscle layer- and lamina muscularis mucosae-projecting nerve fibres. CART-IR nerve terminals located between mucosal glands of the abomasum frequently co-stored VIP, NPY and/or SP. Although the exact function of CART in the ovine forestomachs/stomach has to be elucidated, several potential functions (like enteric nerves protection) have been suggested.

Denervation of the porcine ovaries performed during the early luteal phase influenced morphology and function of the gonad

We studied both morphology and steroidogenic activity of ovaries in gilts after bilateral surgical denervation performed on day 3 of the estrous cycle. Blood samples were collected from day 4 of the first estrous cycle to day 11 of the subsequent cycle. Denervation resulted in a dramatic reduction in the number or in the disappearance of tyrosine hydroxylase/dopamine-beta-hydroxylase- and/or neuropeptide Y-immunoreactive nerve fibres. On day 11 of the second cycle, the number of follicles (3-6 mm in diameter) was lower (p<0.001) in the denervated ovaries, while corpora lutea were not present. Neurectomy also led to a decrease in the concentrations of progesterone, androstendione and 17beta-estradiol in the follicular fluid originated from small (1-3 mm in diameter) as well as medium-sized follicles (3-6 mm in diameter). Similar to follicular fluid, concentration of androstendione in the follicular wall of medium-sized follicles decreased in experimental gilts in comparison to that of control animals. In addition, plasma concentrations of LH and steroid hormones were lower in the control than in the experimental group. Our results show that denervation of ovaries during the early luteal phase of the estrous cycle in gilts resulted in the changes in both morphology and steroidogenic activity. These results confirm the important role of the peripheral nerves in the function of ovaries.

Ovarian morphology and hormonal profiles in gilts following surgical denervation at day 12 of the oestrous cycle - preliminary data

To establish the role of the nervous system in the etiopathogenesis of ovarian cysts we studied ovarian morphology and hormonal profiles in gilts that had undergone bilateral surgical denervation at day 12 of the oestrous cycle. Blood samples were collected from day 13 of the first cycle until day 20 of the second studied cycle. On this day the number of follicles (6 to 10 mm in diameter) was lower (p < 0.01) in the denervated ovaries when compared to the control group. Denervation resulted in a dramatic reduction in the number of TH/D betaH- and/or NPY-IR nerve fibres, especially in the vicinity of the follicles. Furthermore, denervation lead to a decrease (p < 0.05-0.001) in plasma concentrations of P(4) (at day 15 and 16 of the first cycle and during the luteal phase of the second studied cycle) and LH and E(2) (mainly during the perioestrous period). These results suggest that sympathetic neurons supplying ovaries may participate in the follicular development and steroidogenesis in gilts.