Differential responses to steroid hormones in fibroblasts from the vocal fold, trachea, and esophagus

Effect of Testosterone on the Thyroarytenoid Muscle and Lamina Propria of Female Rat Vocal Folds

OBJECTIVE

To analyze the effects of androgen therapy on the thyroarytenoid (TA) muscle, expression of androgen receptors (ARs) and hyaluronic acid (HA) concentration in the vocal folds (VFs) of adult female rats.

METHODS

Twenty-one adult female Wistar rats were divided into experimental and control groups. The experimental group received weekly intramuscular injections of nandrolone decanoate for 9 weeks. Following euthanasia and dissection of the VFs, histomorphometric analysis of the TA muscle, immunohistochemical evaluation of ARs, and measurement of HA concentration using the ELISA-like fluorimetric method were performed.

RESULTS

The experimental group exhibited a significantly larger mean fiber cross-sectional area in the TA muscle compared to the control group (434.3 ± 68.6 μm2 versus 305.7 ± 110.1 μm2; p = 0.029), indicating muscle hypertrophy. There was no significant difference in the number of muscle fibers. The experimental group showed higher expression of ARs in the lamina propria (62.0% ± 30.3% versus 22.0% ± 22.8%; p = 0.046) and in the TA muscle (45.0% ± 22.6% versus 18.3% ± 9.8%; p = 0.024). There was no significant difference in the concentration of HA.

CONCLUSION

Exposure of adult female rats to androgen therapy resulted in hypertrophy of the TA muscle and increased expression of ARs in the VFs. The TA muscle seems to be the primary target of testosterone action in the VF, and the up-regulation of ARs might contribute to the persistent deepening of the voice.

LEVEL OF EVIDENCE

NA Laryngoscope, 134:2316-2321, 2024.

Vocal fold fibroblasts and exposure to vibration in vitro: Does sex matter?

Studies have shown that certain vocal fold pathologies are more common in one sex than the other. This is often explained by differences in the composition of the lamina propria and anatomical differences between female and male vocal folds, resulting in e.g. different fundamental frequencies. Here, we investigated a potential sex-specific voice frequency effect in an in vitro setting using vocal fold fibroblasts from one male and one female donor with and without cigarette smoke extract (CSE) addition. After exposure to either male or female vibration frequency with or without CSE, cells and supernatants were harvested. Gene and protein analysis were performed by means of qPCR, western blot, ELISA and Luminex. We found that exposure of cells to both male and female vibration pattern did not elicit significant changes in the expression of extracellular matrix-, inflammation-, and fibrosis-related genes, compared to control cells. The addition of CSE to vibration downregulated the gene expression of COL1A1 in cells exposed to the female vibration pattern, as well as induced MMP1 and PTGS2 in cells exposed to both female and male vibration pattern. The protein expression of MMP1 and COX2 was found to be significantly upregulated only in cells exposed to CSE and female vibration pattern. To conclude, different vibration patterns alone did not cause different responses of the cells. However, the female vibration pattern in combination with CSE had a tendency to elicit/maintain more pro-inflammatory responses in cells than the male vibration pattern.

The Multienzyme Complex Nature of Dehydroepiandrosterone Sulfate Biosynthesis

Dehydroepiandrosterone (DHEA), a precursor of steroid sex hormones, is synthesized by steroid 17-alpha-hydroxylase/17,20-lyase (CYP17A1) with the participation of microsomal cytochrome b5 (CYB5A) and cytochrome P450 reductase (CPR), followed by sulfation by two cytosolic sulfotransferases, SULT1E1 and SULT2A1, for storage and transport to tissues in which its synthesis is not available. The involvement of CYP17A1 and SULTs in these successive reactions led us to consider the possible interaction of SULTs with DHEA-producing CYP17A1 and its redox partners. Text mining analysis, protein-protein network analysis, and gene co-expression analysis were performed to determine the relationships between SULTs and microsomal CYP isoforms. For the first time, using surface plasmon resonance, we detected interactions between CYP17A1 and SULT2A1 or SULT1E1. SULTs also interacted with CYB5A and CPR. The interaction parameters of SULT2A1/CYP17A1 and SULT2A1/CYB5A complexes seemed to be modulated by 3'-phosphoadenosine-5'-phosphosulfate (PAPS). Affinity purification, combined with mass spectrometry (AP-MS), allowed us to identify a spectrum of SULT1E1 potential protein partners, including CYB5A. We showed that the enzymatic activity of SULTs increased in the presence of only CYP17A1 or CYP17A1 and CYB5A mixture. The structures of CYP17A1/SULT1E1 and CYB5A/SULT1E1 complexes were predicted. Our data provide novel fundamental information about the organization of microsomal CYP-dependent macromolecular complexes.

Effects of Repeated Intracordal Glucocorticoid Injection on the Histology and Gene Expression of Rat Vocal Folds

OBJECTIVES

Local injection of glucocorticoids (GCs) into the vocal folds has been used for treating the vocal fold lesions. While the positive effects on vocal fold nodules, polyps, or scarring have been clinically reported, some concern remains around the potential adverse effects such as vocal fold atrophy, and the mechanisms remain unclear. The present study examined the histology and gene expression of locally injected GC into the vocal folds in rats.

METHODS

Thirteen-week-old male Sprague-Dawley rats were used in the experiments. Triamcinolone acetonide (TAA) or saline were administered repeatedly to the right vocal folds at a weekly interval, and rats were euthanized one week after the last administration for histological examination. Genetic examination was assessed hyaluronic acid (HA) metabolism at 1 or 3 days after a single TAA injection by quantitative real-time polymerase chain reaction (qRT-PCR).

RESULTS

The group which underwent four TAA injections showed a significant decrease in HA in the lamina propria (LP), thickness of the LP and total cell numbers of the LP compared with the saline group. In contrast, there was no significant difference in the area of collagen accumulation and the thyroarytenoid muscle, although there was a tendency of atrophy of the muscle. After single injection of TAA, qRT-PCR showed a significant decrease in the expression of HA synthases, Has2 and Has3.

CONCLUSIONS

The current animal study first demonstrates that repeated intracordal injection of GCs may lead to atrophy of vocal folds caused by decrease of deposition of HA in the LP and decrease of gene expression of Has.

Testosterone replacement relieves ligature-induced periodontitis by mitigating inflammation, increasing pro-resolving markers and promoting angiogenesis in rats: A preclinical study

OBJECTIVES

This study aimed to evaluate the inflammatory profile as well as the resolution of inflammation in a ligature-induced periodontal inflammation in rats with depletion and/or supraphysiological testosterone replacement.

DESIGN

Sixty male rats (Holtzman) were used in the present study. Study groups were created as following: (1) Sham (no testicle removal); (2) Orchiectomy (OCX), 3) OCX + Testosterone (OCX + T); (4) Sham + Ligature (SH + L); (5) OCX+L; and 6) OCX + T + L. The surgeries were performed on day 1, and testosterone was administered weekly since day 1. On day 15, a cotton ligature was placed around the lower first molars and maintained for 15 days. Morphological changes in periodontal tissues were determined by histopathological analysis. Immunohistochemistry (factor VIII) and immunoenzymatic assay were performed to evaluate angiogenesis process and (pro- and anti-) inflammatory markers, respectively.

RESULTS

Ligature promoted a marked inflammatory gingival infiltrate and bone loss (P < 0.05). Supraphysiological testosterone treatment increased the percentage of blood vessels, extracellular matrix and fibroblasts in the presence and absence of periodontal inflammation (P < 0.05). A high dose of testosterone increased factor VIII+ blood vessels and IL-10 expression in inflamed gingival tissue, while PGE₂, LXA₄ and MPO were reduced as a result of supraphysiological testosterone administration (P < 0.05).

CONCLUSIONS

These results, in our experimental model, suggest that supraphysiological testosterone treatment stimulated gingival tissue repair during ligature-induced periodontitis, and it seems to be related to an anti-inflammatory and pro-resolutive mechanism resulting by the modulatory effect on PGE₂ and IL-10 related to an enhanced angiogenesis.

Human Identical Sequences, hyaluronan, and hymecromone ─ the new mechanism and management of COVID-19

COVID-19 caused by SARS-CoV-2 has created formidable damage to public health and market economy. Currently, SARS-CoV-2 variants has exacerbated the transmission from person-to-person. Even after a great deal of investigation on COVID-19, SARS-CoV-2 is still rampaging globally, emphasizing the urgent need to reformulate effective prevention and treatment strategies. Here, we review the latest research progress of COVID-19 and provide distinct perspectives on the mechanism and management of COVID-19. Specially, we highlight the significance of Human Identical Sequences (HIS), hyaluronan, and hymecromone ("Three-H") for the understanding and intervention of COVID-19. Firstly, HIS activate inflammation-related genes to influence COVID-19 progress through NamiRNA-Enhancer network. Accumulation of hyaluronan induced by HIS-mediated HAS2 upregulation is a substantial basis for clinical manifestations of COVID-19, especially in lymphocytopenia and pulmonary ground-glass opacity. Secondly, detection of plasma hyaluronan can be effective for evaluating the progression and severity of COVID-19. Thirdly, spike glycoprotein of SARS-CoV-2 may bind to hyaluronan and further serve as an allergen to stimulate allergic reaction, causing sudden adverse effects after vaccination or the aggravation of COVID-19. Finally, antisense oligonucleotides of HIS or inhibitors of hyaluronan synthesis (hymecromone) or antiallergic agents could be promising therapeutic agents for COVID-19. Collectively, Three-H could hold the key to understand the pathogenic mechanism and create effective therapeutic strategies for COVID-19.

Sebocytes contribute to melasma onset

Melasma is a hyperpigmentary disorder with photoaging features, whose manifestations appear on specific face areas, rich in sebaceous glands (SGs). To explore the SGs possible contribution to the onset, the expression of pro-melanogenic and inflammatory factors from the SZ95 SG cell line exposed to single or repetitive ultraviolet (UVA) radiation was evaluated. UVA up-modulated the long-lasting production of α-MSH, EDN1, b-FGF, SCF, inflammatory cytokines and mediators. Irradiated SZ95 sebocyte conditioned media increased pigmentation in melanocytes and the expression of senescence markers, pro-inflammatory cytokines, and growth factors regulating melanogenesis in fibroblasts cultures. Cocultures experiments with skin explants confirmed the role of sebocytes on melanogenesis promotion. The analysis on sebum collected from melasma patients demonstrated that in vivo sebocytes from lesional areas express the UVA-activated pathways markers observed in vitro. Our results indicate sebocytes as one of the actors in melasma pathogenesis, inducing prolonged skin cell stimulation, contributing to localized dermal aging and hyperpigmentation.

The Effects of Amniotic Membrane Transplantation on Vocal Fold Regeneration

OBJECTIVES/HYPOTHESIS

Vocal fold (VF) scar and sulcus cause severe vocal problems, but optimal methods have not been established. Total replacement of the mucosa is required particularly for cases in which the whole lamina propria is occupied by severe fibrosis and vibratory function is totally lost. The amniotic membrane (AM) has been proven to have regenerative potential, as it contains stem cells and growth factors. The current study investigated the biocompatibility and effects of AM for regeneration of the VF mucosa.

STUDY DESIGN

In vitro and in vivo studies.

METHODS

Vocal fold fibroblasts (VFFs) from 13 Sprague-Dawley rats were seeded on AM and subjected to histology and immunohistochemistry, and gene expressions in the VFFs on AM were examined in in vitro study. Twelve New Zealand White rabbits were used in in vivo study. VFs were stripped down and were reconstructed with AM. The regenerative effects were examined 3 months later by histological examination.

RESULTS

In vitro study indicated VFFs survived on AM and stained positively for Ki67, vimentin, and fibronectin. Gene expressions of Has1, Has2, and Hgf were significantly increased in the VFFs on AM compared with the other groups. The in vivo study indicated AM-transplanted VFs showed a significantly higher density of hyaluronic acid and lower density of collagen compared with sham VFs.

CONCLUSIONS

The current preliminary study suggests biocompatibility and possible regenerative effects of AM for VFs.

LEVEL OF EVIDENCE

NA Laryngoscope, 2021.

Predictors of Fibrotic and Bone Tissue Formation With 3-D Reconstructions of Post-implantation Human Temporal Bones

HYPOTHESIS

Years of implantation, surgical insertion approach, and electrode length will impact the volume of new tissue formation secondary to cochlear implantation.

BACKGROUND

New tissue formation, fibrosis, and osteoneogenesis after cochlear implantation have been implicated in increasing impedance and affecting performance of the cochlear implant.

METHODS

3-D reconstructions of 15 archival human temporal bones from patients with a history of cochlear implantation (CI) were generated from H&E histopathologic slides to study factors which affect volume of tissue formation.

RESULTS

Years of implantation was a predictor of osteoneogenesis (r = 0.638, p-value = 0.011) and total new tissue formation (r = 0.588, p-value = 0.021), however not of fibrosis (r = 0.235, p-value = 0.399). Median total tissue formation differed between cochleostomy and round window insertions, 25.98 and 10.34%, respectively (Mann-Whitney U = 7, p = 0.018). No correlations were found between electrode length or angular insertion depth and total new tissue (p = 0.192, p = 0.35), osteoneogenesis (p = 0.193, p = 0.27), and fibrosis (p = 0.498, p = 0.83), respectively. However, the type II error for electrode length and angular insertion depth ranged from 0.73 to 0.90, largely due to small numbers of the shorter electrodes.

CONCLUSIONS

With numbers of cochlear implant recipients increasing worldwide, an understanding of how to minimize intracochlear changes from implantation is important. The present study demonstrates that increasing years of implantation and inserting electrodes via a cochleostomy compared with a round window approach are associated with significantly greater degree of new tissue volume formation. While previous studies have demonstrated increased intracochlear damage in the setting of translocation with longer electrodes, length, and angular insertion depth of CI electrodes were not associated with increased tissue formation.

Sexually dimorphic production of interleukin-6 in respiratory disease

Diverging susceptibility and severity in respiratory diseases is prevalent between males and females. Sex hormones have inconclusively been attributed as the cause of these differences, however, strong evidence exists promoting genetic factors leading to sexual dimorphism. As such, we investigate differential proinflammatory cytokine (interleukin (IL)‐6 and CXCL8) release from TNF‐α stimulated primary human lung fibroblasts in vitro. We present, for the first time, in vitro evidence supporting clinical findings of differential production of IL‐6 between males and females across various respiratory diseases. IL‐6 was found to be produced approximately two times more from fibroblasts derived from females compared to males. As such we demonstrate sexual dimorphism in cytokine production of IL‐6 outside the context of biological factors in the human body. As such, our data highlight that differences exist between males and females in the absence of sex hormones. We, for the first time, demonstrate inherent in vitro differences exist between males and females in pulmonary fibroblasts.

Mechanisms Underlying the Antifibrotic Potential of Estradiol for Vocal Fold Fibrosis

OBJECTIVES/HYPOTHESIS

Vocal fold fibrosis remains a significant clinical challenge. Estrogens, steroid hormones predominantly responsible for secondary sexual characteristics in women, have been shown to alter wound healing and limit fibrosis, but the effects on vocal fold fibrosis are unknown. We sought to elucidate the expression of estrogen receptors and the effects of estrogens on TGF-β1 signaling in rat vocal fold fibroblasts (VFFs).

STUDY DESIGN

In vitro.

METHODS

VFFs were isolated from 10-week-old, male Sprague-Dawley rats, and estrogen receptor alpha (ERα) and G protein-coupled receptor 30 (GPR30) were examined via immunostaining and quantitative polymerase chain reaction (qPCR). VFFs were treated with estradiol (E2, 10^-7 , 10^-8 or 10^-9  M) ± transforming growth factor beta 1 (TGF-β1, 10 ng/mL). ICI 182,780 (ICI, 10^-7  M) or G36 (10^-7  M) were employed as antagonists of ERα or GPR30, respectively. qPCR was employed to determine estrogen receptor-mediated effects of E2 on genes related to fibrosis.

RESULTS

ERα and GPR30 were expressed in VFFs at both the protein and the mRNA levels. E2 (10^-7  M) did not alter Smad3, Smad7, Acta2 mRNA, or extracellular matrix related genes. However, the combination of E2 (10^-8  M) and TGF-β1 significantly increased Smad7 (P = .03) and decreased Col1a1 (P = .04) compared to TGF-β1 alone; this response was negated by the combination of ICI and G36 (P = .009).

CONCLUSIONS

E2 regulated TGF-β1/Smad signaling via estrogen receptors in VFFs. These findings provide insight into potential mechanisms of estrogens on vocal fold injury with the goal of enhanced therapeutics for vocal fold fibrosis.

LEVEL OF EVIDENCE

NA Laryngoscope, 131:2285-2291, 2021.

Loss of Estrogen Receptors is Associated with Increased Tumor Aggression in Laryngeal Squamous Cell Carcinoma

Laryngeal squamous cell carcinoma (LSCC) responds to 17β-estradiol via estrogen-receptor (ER, transcribed from ESR1) dependent mechanisms, but is not recognized as a hormonally responsive cancer. 17β-estradiol production by LSCC cell lines UM-SCC-11A and UM-SCC-12 was examined. Wild type (WT) and ESR1-silenced LSCC cultures and xenografts were examined for 17β-estradiol responsiveness in vivo. 14 LSCC and surrounding epithelial samples at various pathological stages were obtained from patients; ERα and ERβ expression were verified using data from the total cancer genome atlas. UM-SCC-11A and UM-SCC-12 both produce 17β-estradiol, but only UM-SCC-12, not UM-SCC-11A, xenograft tumors grow larger in vivo in response to systemic 17β-estradiol treatments. ERα66 and ERα36 expression inversely correlated with clinical cancer stage and tumor burden. LSCC ERα66 expression was higher compared to surrounding epithelia in indolent samples but lower in aggressive LSCC. ERβ expression was highly variable. High ESR1 expression correlated with improved survival in LSCC. Loss of ERα66 expression inversely correlated with prognosis in LSCC. ERα66 may be a histopathological marker of aggression in LSCC.

Estrogen signaling and estrogen receptors as prognostic indicators in laryngeal cancer

Laryngeal squamous cell carcinoma (LSCC) has been shown to respond to 17β-estradiol. However, the presence and characterization of estrogen receptors (ER) and other sex hormone receptors in LSCC are still being determined. Sex hormone receptors and the way sex hormones impact LSCC tumors are important for understanding which patients would benefit from hormone therapies, such as anti-estrogen therapies. This information also has prognostic value, as there may be a correlation between ER profiles and LSCC aggression. Recent work by our team and others has shown that the canonical ER, estrogen receptor α (ERα), and its splice variant ERα36, are important modulators of estrogen signaling in LSCC. This review describes some common 17β-estradiol signaling pathways, and explains how these signaling pathways might control LSCC tumor growth. We also show that loss of ERα, but not ERα36, imbues LSCC with enhanced aggression, a pattern which has previously only been observed in breast cancer. We make a case for using ERα as a tumorigenic modulator and pathogenic marker in LSCC on par with the use of ERα as a prognostic marker in breast cancer.

Effect of sex hormones on extracellular matrix of lamina propria in rat vocal fold

OBJECTIVES

The role of sex hormones for voice changes in men and women is presently unknown. To determine the effect of sex hormone on the vocal fold, changes of the extracellular matrix (ECM) in vocal fold lamina propria were assessed in orchiectomized (ORX) and ovariectomized (OVX) rats.

METHODS

Male and female Sprague-Dawley rats were divided into sham-operated control male (CON-ORX), ORX, sham-operated female (CON-OVX), and OVX rats. Histological changes and expression of ECM-related genes in lamina propria of the vocal fold were evaluated at 4 and 12 weeks after surgery.

RESULTS

Testosterone and estradiol levels decreased in the ORX and OVX groups, respectively. ORX groups did not have significant changes compared with CON-ORX groups. However, the expression of hyaluronic acid (HA) was decreased in the OVX group compared with the CON-OVX group. The expression of collagen I in OVX was lower than in the CON-OVX group. Collagen III levels were elevated at 4 weeks in the OVX group, but collagen III levels were diminished at 12 weeks in the OVX group. Expression of elastin in the ECM was less dense in the OVX group compared with controls. The expression MMP-1 and MMP-9 showed significantly increase in the OVX group compared to the CON-OVX group.

CONCLUSION

No changes of the ECM-related genes in the vocal fold lamina propria were observed in ORX groups with reduced testosterone. However, changes of several ECM-related genes were observed in OVX groups with decreased estrogen. These results indicate that the vocal fold is an estrogen-sensitive target organ and that decreased estrogen, not testosterone, can affect the expression of several ECM-related molecules of vocal fold.

LEVEL OF EVIDENCE

NA Laryngoscope, 130:732-740, 2020.

Phosphorylation of the glucocorticoid receptor alters SMAD signaling in vocal fold fibroblasts

OBJECTIVES/HYPOTHESIS

Direct glucocorticoid (GC) injection for vocal fold (VF) scarring has evolved as a therapeutic strategy, but the mechanisms underlying the antifibrotic effects remain unclear. GCs act via the glucocorticoid receptor (GR), which is phosphorylated at multiple serine residues in a hormone-dependent manner to affect bioactivity. We hypothesize that GCs regulate SMAD signaling via GR phosphorylation in vocal fold fibroblasts (VFFs).

STUDY DESIGN

In vitro.

METHODS

Human VFFs were treated with dexamethasone (DM; 10^-5 -10^-7 M) ± transforming growth factor (TGF)-β1 (10 ng/mL). RU486 (10^-6 M) was employed to isolate the regulatory effects of GR. Total GR, Ser²¹¹ , and Ser²⁰³ phosphorylation was examined via sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunocytochemistry. Quantitative polymerase chain reaction was employed to determine GR-mediated effects of DM on genes related to fibrosis.

RESULTS

Total GR and Ser²¹¹ phosphorylation was observed predominantly in the nucleus 1 hour after DM administration. DM decreased total GR expression, but Ser²⁰³ and Ser²¹¹ phosphorylation increased. RU486 limited the effects of DM. SMAD3 and SMAD7 mRNA expression significantly decreased 4 hours after DM administration (P < 0.05); this response was negated by RU486. COL1A1 remained unchanged, and ACTA2 significantly increased following 24 hours of DM treatment (P < 0.05).

CONCLUSION

DM regulated TGF-β1 signaling via altered SMAD3 and SMAD7 expression. This response was associated with altered GR phosphorylation. These findings provide insight into the mechanisms of steroidal effects on vocal fold repair; ultimately, we seek to enhance therapeutic strategies for these challenging patients.

LEVEL OF EVIDENCE

NA Laryngoscope, 129:E187-E193, 2019.

Reduced levels of stromal sex hormone-binding globulin and androgen receptor dysfunction in the sperm storage region of the rat epididymis

The cauda epididymidis is the major sperm storage region whose androgenic supply, essential for the sperm viability, is provided by the vasculature and is dependent upon testosterone diffusion through the stromal tissue to reach the epithelial cells. We have focused our efforts on examining the regulation of this important epididymal region by evaluating the impact of the androgen disrupter cimetidine on the epithelial–stromal androgenic microenvironment. Male rats received 100 mg/kg cimetidine (CMTG) or saline (CG) for 50 days, serum testosterone levels were measured and the epididymal cauda region was processed for light and transmission electron microscopy. In the proximal cauda region, the duct diameter was measured and birefringent collagen in the stroma was quantified. TUNEL-labeled epithelial cells were quantified, and androgen receptor (AR), karyopherin alpha (KPNA) and sex hormone-binding globulin (SHBG) levels were analyzed by immunofluorescence and Western blot. CMTG showed reduced duct diameter and high number of apoptotic epithelial cells. In the epithelium, the total AR concentration and the KPNA immunoreactivity were reduced, and a weak/absent AR nuclear immunofluorescence was observed in contrast to the enhanced AR immunolabeling observed in the cytoplasm of the epithelial cells. A significant reduction of collagen and SHBG levels in the stroma was also observed. Cimetidine treatment impairs AR nuclear import in the epithelium, causing androgenic dysfunction and subsequent epithelial cell apoptosis and duct atrophy. The connective tissue atrophy and reduction of SHBG stromal levels associated with epithelial androgenic dysfunction indicate a possible role of stromal SHBG in the androgenic supply of the sperm storage region of the epididymis.

Effects of Intracordal Estradiol and Dexamethasone Injection on Wound Healing in Vocal Fold Injuries

OBJECTIVE

The aim of this study was to investigate the effects of intracordal estradiol and dexamethasone injection on wound healing in vocal fold injuries.

STUDY DESIGN

A prospective controlled animal study was carried out.

SETTING

This study was conducted at a tertiary center.

SUBJECTS-METHODS

Ten rabbits were randomly divided into two groups. As surgical procedure, cordotomy technique was performed in the middle third of the vocal folds bilaterally. In the first group, 0.1 mL of dexamethasone was injected into the right side, and 0.1 mL of saline was injected into the left side. In the second group, 0.1 mL of estradiol was injected into the right side, and 0.1 mL of saline was injected into the left side. Animals were sacrificed after 1 month and laryngeal specimens were evaluated histopathologically.

RESULTS

No statistically significant difference was observed in terms of inflammatory response, epithelial thickness, type I and III collagen, and hyaluronic acid parameters in dexamethasone and estradiol injections compared to the saline injection. In terms of elastin level, estradiol injection demonstrated statistically higher values compared to the saline injection. Elastin level of dexamethasone injected vocal folds was not statistically different compared to the saline injection. No significant differences were observed in terms of inflammatory response, epithelial thickness, type I and III collagen, and hyaluronic acid parameters between the estradiol and dexamethasone injected vocal folds.

CONCLUSION

It is thought that the effects of estradiol or dexamethasone injections may have similar effects on wound healing in vocal fold injuries. Intracordal estradiol injection has positive effects on tissue elastin levels.

Methylprednisolone microsphere sustained-release membrane inhibits scar formation at the site of peripheral nerve lesion

Corticosteroids are widely used for the treatment of acute central nervous system injury. However, their bioactivity is limited by their short half-life. Sustained release of glucocorticoids can prolong their efficacy and inhibit scar formation at the site of nerve injury. In the present study, we wrapped the anastomotic ends of the rat sciatic nerve with a methylprednisolone sustained-release membrane. Compared with methylprednisone alone or methylprednisone microspheres, the methylprednisolone microsphere sustained-release membrane reduced tissue adhesion and inhibited scar tissue formation at the site of anastomosis. It also increased sciatic nerve function index and the thickness of the myelin sheath. Our findings show that the methylprednisolone microsphere sustained-release membrane effectively inhibits scar formation at the site of anastomosis of the peripheral nerve, thereby promoting nerve regeneration.

Tumor-associated fibroblasts predominantly come from local and not circulating precursors

Fibroblasts are common cell types in cancer stroma and lay down collagen required for survival and growth of cancer cells. Although some cancer therapy strategies target tumor fibroblasts, their origin remains controversial. Multiple publications suggest circulating mesenchymal precursors as a source of tumor-associated fibroblasts. However, we show by three independent approaches that tumor fibroblasts derive primarily from local, sessile precursors. First, transplantable tumors developing in a mouse expressing green fluorescent reporter protein (EGFP) under control of the type I collagen (Col-I) promoter (COL-EGFP) had green stroma, whereas we could not find COL-EGFP(+) cells in tumors developing in the parabiotic partner lacking the fluorescent reporter. Lack of incorporation of COL-EGFP(+) cells from the circulation into tumors was confirmed in parabiotic pairs of COL-EGFP mice and transgenic mice developing autochthonous intestinal adenomas. Second, transplantable tumors developing in chimeric mice reconstituted with bone marrow cells from COL-EGFP mice very rarely showed stromal fibroblasts expressing EGFP. Finally, cancer cells injected under full-thickness COL-EGFP skin grafts transplanted in nonreporter mice developed into tumors containing green stromal cells. Using multicolor in vivo confocal microscopy, we found that Col-I-expressing fibroblasts constituted approximately one-third of the stromal mass and formed a continuous sheet wrapping the tumor vessels. In summary, tumors form their fibroblastic stroma predominantly from precursors present in the local tumor microenvironment, whereas the contribution of bone marrow-derived circulating precursors is rare.

Fundamental Frequency of Crying in Two-month-old Boys and Girls: Do Sex Hormones During Mini-puberty Mediate Differences?

OBJECTIVE

To evaluate whether the puberty-like sex hormone surge during the first months of life (mini-puberty) affects fundamental frequency (fo) in infant crying as one would derive from hormone influences on voice in adults.

STUDY DESIGN

Populational prospective study.

PARTICIPANTS

Twenty healthy normal-hearing infants (nine boys) were recruited for participation.

METHODS

Spontaneously uttered cries were collected from each infant at 8 weeks of age. The cries were acoustically analyzed for mean fo and fo range. The fo properties were correlated to the average serum levels of bioavailable estradiol (E2) (mean E2/sex hormone-binding globulin [SHBG]) and testosterone (T) (mean T/SHBG) across the second month of life.

RESULTS

Whereas no significant hormone effect was found for mean fo, a significant negative correlation (r = -0.55) was found between fo range and mean E2/SHBG. No indication for a T influence on fo features was found at this age. Although girls showed a slightly higher mean E2 concentration than boys did, the observed differences in cry fo range were judged to be reflective of an infant's serum concentration of E2 rather than a sex-based difference.

CONCLUSION

In the absence of laryngeal size differences between female and male infants, the result was interpreted as indicative of an E2 influence on viscoelastic properties of the vocal folds. In our opinion, the investigation of young infants' vocalizations during the early postnatal surge of sex steroids (mini-puberty) may advance our understanding of the mechanisms mediating average sex differences in vocal development and early communication.

Sexual Dimorphism in the Regulation of Estrogen, Progesterone, and Androgen Receptors by Sex Steroids in the Rat Airway Smooth Muscle Cells

The role of sex hormones in lung is known. The three main sex steroid receptors, estrogen, progesterone, and androgen, have not been sufficiently studied in airway smooth muscle cells (ASMC), and the sex hormone regulation on these receptors is unknown. We examined the presence and regulation of sex hormone receptors in female and male rat ASMC by Western blotting and flow cytometry. Gonadectomized rats were treated with 17β-estradiol, progesterone, 17β-estradiol + progesterone, or testosterone. ASMC were enzymatically isolated from tracheas and bronchi. The experiments were performed with double staining flow cytometry (anti-α-actin smooth muscle and antibodies to each hormone receptor). ERα, ERβ, tPR, and AR were detected in females or males. ERα was upregulated by E2 and T and downregulated by P4 in females; in males, ERα was downregulated by P4, E + P, and T. ERβ was downregulated by each treatment in females, and only by E + P and T in males. tPR was downregulated by P4, E + P, and T in females. No hormonal regulation was observed in male receptors. AR was downregulated in males treated with E + P and T. We have shown the occurrence of sex hormone receptors in ASMC and their regulation by the sex hormones in female and male rats.