Bone Densitometry in Transgender and Gender Non-Conforming (TGNC) Individuals: 2019 ISCD Official Position

The indications for initial and follow-up bone mineral density (BMD) in transgender and gender nonconforming (TGNC) individuals are poorly defined, and the choice of which gender database to use to calculate Z-scores is unclear. Herein, the findings of the Task Force are presented after a detailed review of the literature. As long as a TGNC individual is on standard gender-affirming hormone treatment, BMD should remain stable to increasing, so there is no indication to monitor for bone loss or osteoporosis strictly on the basis of TGNC status. TGNC individuals who experience substantial periods of hypogonadism (>1 yr) might experience bone loss or failure of bone accrual during that time, and should be considered for baseline measurement of BMD. To the extent that this hypogonadism continues over time, follow-up measurements can be appropriate. TGNC individuals who have adequate levels of endogenous or exogenous sex steroids can, of course, suffer from other illnesses that can cause osteoporosis and bone loss, such as hyperparathyroidism and steroid use; they should have measurement of BMD as would be done in the cisgender population. There are no data that TGNC individuals have a fracture risk different from that of cisgender individuals, nor any data to suggest that BMD predicts their fracture risk less well than in the cisgender population. The Z-score in transgender individuals should be calculated using the reference data (mean and standard deviation) of the gender conforming with the individual's gender identity. In gender nonconforming individuals, the reference data for the sex recorded at birth should be used. If the referring provider or the individual requests, a set of "male" and "female" Z-scores can be provided, calculating the Z-score against male and female reference data, respectively.

Managing the risk of venous thromboembolism in transgender adults undergoing hormone therapy

Introduction: Venous thromboembolism (VTE) is a potential risk of estrogen therapy. However, data show an improvement in the quality of life for transgender people who use feminizing hormone therapy. With few transgender-specific data, guidance may be drawn from cisgender (nontransgender) data, with a focus on hormonal birth control and postmenopausal hormone replacement therapy (HRT). The aim of this review is to examine the degree to which routes of administration, patient comorbidities, and type of hormone utilized affect the safety of estrogen therapy. Methods: We identified 6,349 studies by searching PubMed with the terms "transgender", "estrogen", "VTE", and "HRT". Of these, there were only 13 studies between 1989 and 2018 that investigated the effects of hormone therapy, including types of estrogens used, in transgender women and men. Results: The data suggest that the route of hormone administration, patient demographics, and patient comorbidities all affect estrogen's link with VTE. For example, avoiding ethinyl estradiol might make the use of hormone therapy in trans feminine individuals safer than oral birth control. Data from both cis and trans groups suggest additional VTE risk associated with the use of progestins. While transdermal estrogens dosed up to 0.1 mg/day or below appear lower risk for VTE than other forms of estrogen, it is unclear whether this is related to the delivery method or a dose effect. Finally, even if the risk from exogenous estrogen use remains significant statistically, the absolute clinical risk remains low. Conclusion: Clinicians should avoid the use of ethinyl estradiol. Additionally, data suggest that progestins should be avoided for transgender individuals. Further study of the relationship between estrogen use and the risk of VTE will serve to inform the safest care strategies for transgender individuals.

Care of the Transgender Patient

Transgender persons are a diverse group whose gender identity differs from their sex recorded at birth. Some choose to undergo medical treatment to align their physical appearance with their gender identity. Barriers to accessing appropriate and culturally competent care contribute to health disparities in transgender persons, such as increased rates of certain types of cancer, substance abuse, mental health conditions, infections, and chronic diseases. Thus, it is important that clinicians understand the specific medical issues that are relevant to this population.

Etiology of Gender Identity

This article reviews the current literature characterizing potential factors associated with the etiologies of gender identity. The PubMed database was searched for all literature that assessed key elements affecting development of gender identity. Current models attribute gender identity etiology to endogenous biology along with prenatal androgen exposure. However, no genetic loci or specific neuroanatomic regions have been consistently identified as the single explanation for transgender identity. Although environment may play a role in gender expression, there are no data to suggest an exogenous explanation for the development of gender identity.

Gaps in transgender medical education among healthcare providers: A major barrier to care for transgender persons

A lack of access to knowledgeable providers is the greatest reported barrier to care for transgender individuals. The purpose of this manuscript is to review the recent literature characterizing transgender medicine education for medical providers and to summarize effective interventions for improving education in transgender care. The PubMed database was searched for all literature that assessed transgender medical education among physicians or trainees and all papers that reported results of transgender-specific educational interventions. Literature that only evaluated general lesbian, gay, bisexual, and transgender (LGBT) educational interventions was excluded. The lack of education in transgender care continues among providers across all levels of medical education from medical students and physician trainees to primary care providers, endocrinologists and other specialists involved in transgender care. Several interventions have been shown to effectively improve transgender knowledge and cultural competency. Education among healthcare providers is deficient and is considered a major barrier to care for transgender individuals. Effective interventions should be applied to fundamental medical education. Additional focused education also should be taught with specialty-appropriate content to produce needed proficiency among providers of transgender care.

The Boston Medical Center Experience: An Achievable Model for the Delivery of Transgender Medical Care at an Academic Medical Center

Despite increasing appreciation for the medical needs of transgender individuals, the organization of transgender medical care remains suboptimal. Transgender individuals report difficulty in finding providers who have adequate expertise in caring for transgender patients, a lack of provider cultural competence, health system barriers, and discrimination in healthcare settings. At Boston Medical Center (BMC), we sought to address these gaps within an existing academic medical center. In February 2016, BMC established a Center for Transgender Medicine and Surgery (CTMS) to provide a single address for patients to obtain transgender-specific services across a spectrum of healthcare needs. With the establishment of a CTMS at BMC, we were able to leverage broad transgender medical coverage across multiple specialties within an existing academic medical framework. Furthermore, the development of the CTMS resulted in our identification of multiple gaps in transgender healthcare which we could target. Large gaps in care for our institution included genital surgery, perisurgical support, adolescent care, and care coordination. Notably, most of our interventions used existing resources. We propose that this is a replicable model that should be adopted by other academic medical institutions.

Clinical Exposure to Transgender Medicine Improves Students' Preparedness Above Levels Seen with Didactic Teaching Alone: A Key Addition to the Boston University Model for Teaching Transgender Healthcare

Purpose: Transgender individuals are medically underserved in the United States and face many documented disparities in care due to providers' lack of education, training, and comfort. We have previously demonstrated that specific transgender medicine content in a medical school curriculum increases students' willingness to treat transgender patients. However, we have also identified that those same students are less comfortable with transgender care relative to care for lesbian, gay, and bisexual patients. We aimed to demonstrate that clinical exposure to care for transgender patients would help close this gap.

Methods: At Boston University School of Medicine, we piloted a transgender medicine elective where students rotate on services that provide clinical care for transgender individuals. Pre- and postsurveys were administered to students who participated in the elective.

Results: After completing the elective, students who reported “high” comfort increased from 45% (9/20) to 80% (16/20) (p=0.04), and students who reported “high” knowledge regarding management of transgender patients increased from 0% (0/20) to 85% (17/20) (p<0.001).

Conclusion: Although integrating evidence-based, transgender-specific content into medical curricula improves student knowledge and comfort with transgender medical care, gaps remain. Clinical exposure to transgender medicine during clinical years can contribute to closing that gap and improving access to care for transgender individuals.

Endocrine Treatment of Gender-Dysphoric/Gender-Incongruent Persons: An Endocrine Society Clinical Practice Guideline

Objective

To update the "Endocrine Treatment of Transsexual Persons: An Endocrine Society Clinical Practice Guideline," published by the Endocrine Society in 2009.

Participants

The participants include an Endocrine Society-appointed task force of nine experts, a methodologist, and a medical writer.

Evidence

This evidence-based guideline was developed using the Grading of Recommendations, Assessment, Development, and Evaluation approach to describe the strength of recommendations and the quality of evidence. The task force commissioned two systematic reviews and used the best available evidence from other published systematic reviews and individual studies.

Consensus Process

Group meetings, conference calls, and e-mail communications enabled consensus. Endocrine Society committees, members and cosponsoring organizations reviewed and commented on preliminary drafts of the guidelines.

Conclusion

Gender affirmation is multidisciplinary treatment in which endocrinologists play an important role. Gender-dysphoric/gender-incongruent persons seek and/or are referred to endocrinologists to develop the physical characteristics of the affirmed gender. They require a safe and effective hormone regimen that will (1) suppress endogenous sex hormone secretion determined by the person's genetic/gonadal sex and (2) maintain sex hormone levels within the normal range for the person's affirmed gender. Hormone treatment is not recommended for prepubertal gender-dysphoric/gender-incongruent persons. Those clinicians who recommend gender-affirming endocrine treatments-appropriately trained diagnosing clinicians (required), a mental health provider for adolescents (required) and mental health professional for adults (recommended)-should be knowledgeable about the diagnostic criteria and criteria for gender-affirming treatment, have sufficient training and experience in assessing psychopathology, and be willing to participate in the ongoing care throughout the endocrine transition. We recommend treating gender-dysphoric/gender-incongruent adolescents who have entered puberty at Tanner Stage G2/B2 by suppression with gonadotropin-releasing hormone agonists. Clinicians may add gender-affirming hormones after a multidisciplinary team has confirmed the persistence of gender dysphoria/gender incongruence and sufficient mental capacity to give informed consent to this partially irreversible treatment. Most adolescents have this capacity by age 16 years old. We recognize that there may be compelling reasons to initiate sex hormone treatment prior to age 16 years, although there is minimal published experience treating prior to 13.5 to 14 years of age. For the care of peripubertal youths and older adolescents, we recommend that an expert multidisciplinary team comprised of medical professionals and mental health professionals manage this treatment. The treating physician must confirm the criteria for treatment used by the referring mental health practitioner and collaborate with them in decisions about gender-affirming surgery in older adolescents. For adult gender-dysphoric/gender-incongruent persons, the treating clinicians (collectively) should have expertise in transgender-specific diagnostic criteria, mental health, primary care, hormone treatment, and surgery, as needed by the patient. We suggest maintaining physiologic levels of gender-appropriate hormones and monitoring for known risks and complications. When high doses of sex steroids are required to suppress endogenous sex steroids and/or in advanced age, clinicians may consider surgically removing natal gonads along with reducing sex steroid treatment. Clinicians should monitor both transgender males (female to male) and transgender females (male to female) for reproductive organ cancer risk when surgical removal is incomplete. Additionally, clinicians should persistently monitor adverse effects of sex steroids. For gender-affirming surgeries in adults, the treating physician must collaborate with and confirm the criteria for treatment used by the referring physician. Clinicians should avoid harming individuals (via hormone treatment) who have conditions other than gender dysphoria/gender incongruence and who may not benefit from the physical changes associated with this treatment.

Endocrine Treatment of Gender-Dysphoric/Gender-Incongruent Persons: An Endocrine Society Clinical Practice Guideline

OBJECTIVE

To update the "Endocrine Treatment of Transsexual Persons: An Endocrine Society Clinical Practice Guideline," published by the Endocrine Society in 2009.

PARTICIPANTS

The participants include an Endocrine Society-appointed task force of nine experts, a methodologist, and a medical writer.

EVIDENCE

This evidence-based guideline was developed using the Grading of Recommendations, Assessment, Development, and Evaluation approach to describe the strength of recommendations and the quality of evidence. The task force commissioned two systematic reviews and used the best available evidence from other published systematic reviews and individual studies.

CONSENSUS PROCESS

Group meetings, conference calls, and e-mail communications enabled consensus. Endocrine Society committees, members and cosponsoring organizations reviewed and commented on preliminary drafts of the guidelines.

CONCLUSION

Gender affirmation is multidisciplinary treatment in which endocrinologists play an important role. Gender-dysphoric/gender-incongruent persons seek and/or are referred to endocrinologists to develop the physical characteristics of the affirmed gender. They require a safe and effective hormone regimen that will (1) suppress endogenous sex hormone secretion determined by the person's genetic/gonadal sex and (2) maintain sex hormone levels within the normal range for the person's affirmed gender. Hormone treatment is not recommended for prepubertal gender-dysphoric/gender-incongruent persons. Those clinicians who recommend gender-affirming endocrine treatments-appropriately trained diagnosing clinicians (required), a mental health provider for adolescents (required) and mental health professional for adults (recommended)-should be knowledgeable about the diagnostic criteria and criteria for gender-affirming treatment, have sufficient training and experience in assessing psychopathology, and be willing to participate in the ongoing care throughout the endocrine transition. We recommend treating gender-dysphoric/gender-incongruent adolescents who have entered puberty at Tanner Stage G2/B2 by suppression with gonadotropin-releasing hormone agonists. Clinicians may add gender-affirming hormones after a multidisciplinary team has confirmed the persistence of gender dysphoria/gender incongruence and sufficient mental capacity to give informed consent to this partially irreversible treatment. Most adolescents have this capacity by age 16 years old. We recognize that there may be compelling reasons to initiate sex hormone treatment prior to age 16 years, although there is minimal published experience treating prior to 13.5 to 14 years of age. For the care of peripubertal youths and older adolescents, we recommend that an expert multidisciplinary team comprised of medical professionals and mental health professionals manage this treatment. The treating physician must confirm the criteria for treatment used by the referring mental health practitioner and collaborate with them in decisions about gender-affirming surgery in older adolescents. For adult gender-dysphoric/gender-incongruent persons, the treating clinicians (collectively) should have expertise in transgender-specific diagnostic criteria, mental health, primary care, hormone treatment, and surgery, as needed by the patient. We suggest maintaining physiologic levels of gender-appropriate hormones and monitoring for known risks and complications. When high doses of sex steroids are required to suppress endogenous sex steroids and/or in advanced age, clinicians may consider surgically removing natal gonads along with reducing sex steroid treatment. Clinicians should monitor both transgender males (female to male) and transgender females (male to female) for reproductive organ cancer risk when surgical removal is incomplete. Additionally, clinicians should persistently monitor adverse effects of sex steroids. For gender-affirming surgeries in adults, the treating physician must collaborate with and confirm the criteria for treatment used by the referring physician. Clinicians should avoid harming individuals (via hormone treatment) who have conditions other than gender dysphoria/gender incongruence and who may not benefit from the physical changes associated with this treatment.

OBSERVED DEFICIENCIES IN MEDICAL STUDENT KNOWLEDGE OF TRANSGENDER AND INTERSEX HEALTH

OBJECTIVE

Lesbian, gay, bisexual, transgender, and intersex (LGBTI) patients face many well-documented disparities in care which among transgender and intersex people can often be traced to providers' lack of knowledge.

METHODS

We administered surveys to examine the self-assessed knowledge and attitudes of all medical students at Boston University regarding different LGBTI subpopulations. Survey questions were based on a Likert scale from 1 to 5; analysis was conducted with Wilcoxon rank sum tests.

RESULTS

Overall there was a response rate of 24%, with the number of responses varying by class. Three of the 4 surveyed classes reported lower knowledge about transgender health than LGB health. Every class reported significantly lower knowledge of intersex health in comparison to LGB. Comfort with transgender or with intersex patients was lower than with LGB patients for all surveyed classes. Students across all self-identified groups (LGBTI, ally, not an ally) reported significantly lower average responses for knowledge and comfort regarding transgender or intersex health in comparison to that of LGB. Students in their preclinical years reported lower levels of knowledge in comparison with students in their clinical years. Students who identified as LGBTI reported significantly higher knowledge and comfort with only LGB and transgender health when compared with students who didn't identify as LGBTI. Respondents more frequently requested additional learning opportunities in transgender and intersex health than in LGB health.

CONCLUSION

Self-reported knowledge of transgender and intersex health lags behind knowledge of LGB health, though these deficits appear partially responsive to targeted educational intervention.

ABBREVIATIONS

BUSM = Boston University School of Medicine LGB = lesbian, gay, and bisexual LGBT = lesbian, gay, bisexual, and transgender LGBTI = lesbian, gay, bisexual, transgender, and intersex M1 = first-year medical student class M2 = second-year medical student class M3 = third-year medical student class M4 = fourth-year medical student class.

PREVALENCE AND TYPES OF GENDER-AFFIRMING SURGERY AMONG A SAMPLE OF TRANSGENDER ENDOCRINOLOGY PATIENTS PRIOR TO STATE EXPANSION OF INSURANCE COVERAGE

OBJECTIVE

Transgender individuals now have many options for medical intervention, including gender-affirmation surgeries. However, it is unknown how common it is for transgender individuals to undergo these surgeries. The purpose of this cross-sectional study was to assess the prevalence of gender-affirming surgeries among transgender patients in 2015, which was immediately prior to insurance changes that made gender-affirming surgery more affordable for Massachusetts residents.

METHODS

A retrospective chart review of 99 transgender patients was performed at the Endocrinology Clinic at Boston Medical Center, an urban safety net hospital. The records for 99 transgender subjects who received treatment between 2004-2015, including 28 transmen and 71 transwomen, were examined. The outcome measures were the types of medical interventions chosen by transgender patients, which included hormone therapy, chest surgery, gonadectomy, genital surgery, and facial surgery.

RESULTS

Thirty-five percent of subjects had undergone at least one gender-affirming surgery. Transmen were more likely to have had surgery than transwomen (54% vs. 28%). Twenty-five percent of patients had chest surgery, 13% had genital surgery or gonadectomy, and 8% had facial surgery.

CONCLUSION

In 2015, a majority of transgender endocrinology clinic patients had not undergone any type of gender-affirmation surgery. Among those who did elect to have a surgery, genital surgery or gonadectomy were uncommon. The low rate of surgery among this sample of transgender patients may be attributable to the financial cost, lack of interest in surgery, or that genital surgery is not a high priority for transgender individuals relative to surgery to change visible features such as face and chest. Abbreviation: HT = hormone therapy.

Scalp Hair Regrowth in Hormone-Treated Transgender Woman

Evidence of androgenetic alopecia, or male pattern baldness, can be distressing for transgender women. Here we present the case of a transgender woman with scalp hair regrowth after ∼6 months on oral estradiol and spironolactone therapy achieving testosterone levels within normal female range.

Evidence supporting the biologic nature of gender identity

OBJECTIVE

To review current literature that supports a biologic basis of gender identity.

METHODS

A traditional literature review.

RESULTS

Evidence that there is a biologic basis for gender identity primarily involves (1) data on gender identity in patients with disorders of sex development (DSDs, also known as differences of sex development) along with (2) neuroanatomical differences associated with gender identity.

CONCLUSIONS

Although the mechanisms remain to be determined, there is strong support in the literature for a biologic basis of gender identity.

Gaps in Transgender Medicine Content Identified Among Canadian Medical School Curricula

Purpose: The transgender community is a diverse group that requires unique consideration in the healthcare setting. However, several studies have suggested that their needs are not currently being met by our medical system. Although the reason for this discrepancy is likely multifactorial, inadequate training of healthcare professionals to manage this population has been cited as a contributing factor.

Methods: To evaluate the role that Canadian medical schools play in addressing these proposed deficits, program administrators were invited to provide curricular information detailing their delivery of transgender health, and medical students were surveyed to assess the impact of current curricula on their knowledge, attitudes, and experiences with regard to transgender health.

Results: Six of fourteen schools provided curricular information about their instruction in transgender health and wide variation was found; 255/1152 University of British Columbia (UBC) students and 155/2358 students from eight other Canadian medical schools responded to the survey. Greater than 95% of responders agreed that transgender issues are important and should be addressed by physicians. However, fewer than 10% of students felt that they were sufficiently knowledgeable to do so. At UBC, there was no significant improvement in the self-reported knowledge levels after receiving the transgender-related curricula, and only 24% of students felt the topic was proficiently taught.

Conclusion: This study showed that the majority of students who responded do not feel comfortable addressing the needs of transgender individuals in a healthcare setting and suggests that a reevaluation of related curricula may be warranted.

Barriers to healthcare for transgender individuals

PURPOSE OF REVIEW

Transgender persons suffer significant health disparities and may require medical intervention as part of their care. The purpose of this manuscript is to briefly review the literature characterizing barriers to healthcare for transgender individuals and to propose research priorities to understand mechanisms of those barriers and interventions to overcome them.

RECENT FINDINGS

Current research emphasizes sexual minorities' self-report of barriers, rather than using direct methods. The biggest barrier to healthcare reported by transgender individuals is lack of access because of lack of providers who are sufficiently knowledgeable on the topic. Other barriers include: financial barriers, discrimination, lack of cultural competence by providers, health systems barriers, and socioeconomic barriers.

SUMMARY

National research priorities should include rigorous determination of the capacity of the US healthcare system to provide adequate care for transgender individuals. Studies should determine knowledge and biases of the medical workforce across the spectrum of medical training with regard to transgender medical care; adequacy of sufficient providers for the care required, larger social structural barriers, and status of a framework to pay for appropriate care. As well, studies should propose and validate potential solutions to address identified gaps.

Priorities for transgender medical and healthcare research

PURPOSE OF REVIEW

Transgender individuals experience unique health disparities but are the subject of little focused health research. This manuscript reviews current literature on transgender medical and mental health outcomes and proposes research priorities to address knowledge gaps.

RECENT FINDINGS

Published research in transgender healthcare consists primarily of case reports, retrospective and cross-sectional studies, involving largely European settings. Challenges to US-based transgender health research include a diverse population where no single center has sufficient patient base to conduct clinical research with statistical rigor. Treatment regimens are heterogeneous and warrant study for best practices. Current research suggests increased mortality and depression in transgender individuals not receiving optimal care, and possibly a modest increase in cardiovascular risk related to hormone therapy. Current evidence does not support concerns for hormone-related malignancy risk.

SUMMARY

The priorities for transgender medical outcomes research should be to determine health disparities and comorbid health conditions over the life span, along with the effects of mental health, medical, and surgical interventions on morbidity and mortality. Specific outcomes of interest based on frequency in the literature, potential severity of outcome, and patient-centered interest, include affective disorders, cardiovascular disease, malignancies, fertility, and time dose-related responses of specific interventions.

Advancing methods for US transgender health research

PURPOSE OF REVIEW

This article describes methodological challenges, gaps, and opportunities in US transgender health research.

RECENT FINDINGS

Lack of large prospective observational studies and intervention trials, limited data on risks and benefits of sex affirmation (e.g., hormones and surgical interventions), and inconsistent use of definitions across studies hinder evidence-based care for transgender people. Systematic high-quality observational and intervention-testing studies may be carried out using several approaches, including general population-based, health systems-based, clinic-based, venue-based, and hybrid designs. Each of these approaches has its strength and limitations; however, harmonization of research efforts is needed. Ongoing development of evidence-based clinical recommendations will benefit from a series of observational and intervention studies aimed at identification, recruitment, and follow-up of transgender people of different ages, from different racial, ethnic, and socioeconomic backgrounds and with diverse gender identities.

SUMMARY

Transgender health research faces challenges that include standardization of lexicon, agreed upon population definitions, study design, sampling, measurement, outcome ascertainment, and sample size. Application of existing and new methods is needed to fill existing gaps, increase the scientific rigor and reach of transgender health research, and inform evidence-based prevention and care for this underserved population.

Hormone therapy in transgender adults is safe with provider supervision; A review of hormone therapy sequelae for transgender individuals

INTRODUCTION

Some providers report concern for the safety of transgender hormone therapy (HT).

METHODS

This is a systematic literature review of HT safety for transgender adults.

RESULTS

Current literature suggests HT is safe when followed carefully for certain risks. The greatest health concern for HT in transgender women is venous thromboembolism. HT among transgender men appears to cause polycythemia. Both groups experienced elevated fasting glucose. There is no increase in cancer prevalence or mortality due to transgender HT.

CONCLUSION

Although current data support the safety of transgender HT with physician supervision, larger, long-term studies are needed in transgender medicine.

Progress on the road to better medical care for transgender patients

PURPOSE OF REVIEW

In order to improve transgender individuals' access to healthcare, primary care physicians and specialists alike should be knowledgeable about transgender medicine. This review is intended to provide concise transgender hormone treatment guidelines.

RECENT FINDINGS

Transgender individuals report that the lack of knowledgeable providers represents the greatest barrier to transgender medical care. Hormone treatments are generally well tolerated and greatly benefit transgender patients. After physicians recognize that gender identity is stable, hormone treatments for transgender patients are often straightforward. A practical target for hormone therapy for transgender men (female to male) is to increase testosterone levels to the normal male physiological range (300-1000 ng/dl) by administering testosterone. A practical target for hormone therapy for transgender women (male to female) is to decrease testosterone levels to the normal female range (30-100 ng/dl) without supra-physiological levels of estradiol (<200 pg/ml) by administering an antiandrogen and estrogen. Patients should be monitored every 3 months for the first year and then every 6-12 months for hormonal effects.

SUMMARY

Although more studies are required, recently published transgender medical treatment guidelines provide a good start toward making care of transgender patients more generalized and accessible to healthcare providers.

Thyroid hormone and wound healing

Although thyroid hormone is one of the most potent stimulators of growth and metabolic rate, the potential to use thyroid hormone to treat cutaneous pathology has never been subject to rigorous investigation. A number of investigators have demonstrated intriguing therapeutic potential for topical thyroid hormone. Topical T3 has accelerated wound healing and hair growth in rodents. Topical T4 has been used to treat xerosis in humans. It is clear that the use of thyroid hormone to treat cutaneous pathology may be of large consequence and merits further study. This is a review of the literature regarding thyroid hormone action on skin along with skin manifestations of thyroid disease. The paper is intended to provide a context for recent findings of direct thyroid hormone action on cutaneous cells in vitro and in vivo which may portend the use of thyroid hormone to promote wound healing.

Thyroid hormone action on skin

PURPOSE OF REVIEW

To review the current understanding regarding thyroid hormone action on skin. To provide a historical context for the recent findings.

RECENT FINDINGS

Although direct thyroid hormone actions have been demonstrated on multiple aspects of cutaneous biology, rigorous study remains scant. Still, there is a slowly evolving literature supporting the concept that thyroid hormone can directly stimulate epidermis, dermis, and hair. That action may be accessed to treat cutaneous disease.

SUMMARY

Here, we review the literature regarding thyroid hormone action on skin along with skin manifestations of thyroid disease. We provide context for more recent findings of direct thyroid hormone stimulation of cutaneous cell proliferation in vitro and in vivo which may portend the use of thyroid hormone to treat cutaneous pathologies.

Topical androgen antagonism promotes cutaneous wound healing without systemic androgen deprivation by blocking β-catenin nuclear translocation and cross-talk with TGF-β signaling in keratinocytes

Orchidectomy in rodents and lower testosterone levels in men are associated with improved cutaneous wound healing. However, due to the adverse effects on skeletal and sexual tissues, systemic androgen blockade is not a viable therapeutic intervention. Accordingly, we tested the hypothesis that topical application of an androgen antagonist would elicit accelerated wound healing without systemic androgen antagonism. Full-thickness cutaneous wounds were created on adult C57BL6/J mice. Daily topical application of androgen receptor antagonist, flutamide, resulted in improved gap closure similar to orchiectomized controls and faster than orchidectomized mice treated with topical testosterone. In vivo data showed that the effects of androgen antagonism on wound closure primarily accelerate keratinocytes migration without effecting wound contraction. Consequently, mechanisms of testosterone action on reepithelialization were investigated in vitro by scratch wounding assays in confluent keratinocytes. Testosterone inhibited keratinocyte migration and this effect was in part mediated through promotion of nuclear translocation of β-catenin and by attenuating transforming growth factor-β (TGF-β) signaling through β-catenin. The link between Wnt and TGF beta signaling was confirmed by blocking β-catenin and by following TGF-β-induced transcription of a luciferase reporter gene. Together, these data show that blockade of β-catenin can, as a potential target for novel therapeutic interventions, accelerate cutaneous wound healing.

The thyroid hormone degrading type 3 deiodinase is the primary deiodinase active in murine epidermis

INTRODUCTION

Many tissues express thyroid hormone metabolizing deiodinases that both activate and inactivate thyroid hormones through conversion processes. Many believe that the primary role of thyroid hormone deiodinases is the activation of the prohormone thyroxine (T(4)) to the active hormone triiodothyronine because athyreotic humans can be treated with T(4) alone. In our hands a nonspecific deiodinase inhibitor (iopanoic acid [IOP]) decreased cutaneous cell proliferation in vitro, so we hypothesized that topical IOP would inhibit epidermal proliferation in vivo.

METHODS

IOP was applied topically to mice. Treatments were applied daily for 1 week. Skin biopsies were either stained for 5-bromo-2-deoxyuridine or flash-frozen to assay for deiodinase activity.

RESULTS

Topical IOP resulted in a dose-dependent increase in epidermal proliferation. Assay revealed significant inactivating type 3 deiodinase (Dio3) activity in the epidermis but little or no activating (Dio1 or Dio2) activity. Dio3 activity was decreased 44%±21% in epidermis from mice treated with low-dose IOP and 80%±4% in epidermis from mice treated with high-dose IOP (p<0.001).

CONCLUSION

We hypothesize that keratinocytes express Dio3 in vivo to maintain cutaneous health and prevent the skin from becoming hyperproliferative. Our data support the developing recognition that the primary role of thyroid hormone deiodinases in some tissues may be the degradation of thyroid hormone to protect the tissue against thyrotoxicosis.

Thyroid hormone action on skin

The skin characteristics associated with thyroid hormone are classic. The name "myxedema" refers to the associated skin condition caused by increased glycosaminoglycan deposition in the skin. Generalized myxedema is still the classic cutaneous sign of hypothyroidism. It is caused by deposition of dermal acid mucopolysaccharides, notably hyaluronic acid. Despite its appearance, the skin does not pit with pressure.

In thyroid fine-needle aspiration, use of bedside-prepared slides significantly increased diagnostic adequacy and specimen cellularity relative to solution-based samples

BACKGROUND

In the United States, the prevalence among adults of palpable thyroid nodules is 4%-7%, of which 5%-10% may represent thyroid carcinoma. Despite the success of fine-needle aspiration in reducing the need for thyroidectomy, aspirates are inadequate to render a diagnosis in 20% of cases. Minimizing nondiagnostic samples is an important goal in improving this technique. Our objective was to determine whether bedside-prepared slides improve diagnostic adequacy over standard solution-based samples. We further sought to determine the role of needle size.

METHODS

One hundred sixty-two patients were prospectively enrolled. For each, both bedside slides and standard cytology solutions were prepared; the order of preparation alternated from subject to subject. Needle size (21- or 25-gauge) also alternated from subject to subject. Slides were evaluated by pathologists blinded to needle size. The study took place in the endocrinology clinic at Boston Medical Center, the tertiary referral hospital of the Boston University School of Medicine. Key outcomes were diagnostic adequacy and specimen cellularity.

RESULTS

Compared to standard solution-based samples, bedside slides provided more cellular specimens (p < 0.01) and fewer nondiagnostic samples (p = 0.016). When standard solution-based samples were used as the sole method of preparation, 21-gauge needles provided improved diagnostic adequacy.

CONCLUSIONS

Bedside-prepared slides offer improved diagnostic adequacy and specimen cellularity over solution-based samples. The difference may be especially important when using smaller (25-gauge) needles to perform fine-needle aspiration. When solution-based samples are used, larger (21-gauge) needles provide more diagnostic specimens.

Male sex, African American race or ethnicity, and triiodothyronine levels at diagnosis predict weight gain after antithyroid medication and radioiodine therapy for hyperthyroidism

OBJECTIVE

To determine whether racial or ethnic differences affect weight gain after treatment of hyperthyroidism and to reassess established risk factors such as sex, age, and cause of hyperthyroidism.

METHODS

We conducted a retrospective review of medical records of 111 patients treated with radioiodine (RAI) for hyperthyroidism, with or without preceding antithyroid medication, during 2002 to 2005. We ascertained age, sex, race or ethnicity, insurance status, compliance with visits, serum triiodothyronine (T3) level at diagnosis, and cause of hyperthyroidism. Weights and serum thyroidstimulating hormone levels were obtained at diagnosis, at time of RAI therapy, and at 0 to 4 months, 4 to 8 months, 8 to 12 months, and 24 months after RAI treatment.

RESULTS

There was a significant weight increase after treatment of hyperthyroidism. Levels of T3 at initial diagnosis of hyperthyroidism, male sex, and black or Hispanic ethnicity were found to be independent predictors of weight gain after RAI treatment. We found a significant interaction between race or ethnicity and sex in multivariate models. There was no difference in thyroid function across racial or ethnic groups or the sexes. Age, cause of hyperthyroidism, posttreatment thyroid-stimulating hormone level, compliance, and insurance status were not found to be significant predictors of weight gain.

CONCLUSION

The T3 level at the time of diagnosis of hyperthyroidism is a strong predictor of weight gain after treatment of hyperthyroidism. Black race or ethnicity and male sex are also risk factors for weight gain.

A thyroid hormone deiodinase inhibitor can decrease cutaneous cell proliferation in vitro

BACKGROUND

Although cutaneous manifestations associated with thyroid dysfunction are classic, the potential for thyroid hormone or its antagonists to treat dermatological disease has not been explored with rigor. The predominant circulating thyroid hormone is the pro-hormone, thyroxine (T(4)). Skin, like many tissues, expresses thyroid hormone deiodinases to convert T(4) to the active thyroid hormone, triiodothyronine (T(3)). Previously, we determined that T(3) is necessary for optimal growth of keratinocytes and fibroblasts. The first hypothesis of this experiment was that the deiodinase inhibitor iopanoic acid (IOP) could inhibit cutaneous cell proliferation. The second hypothesis of this experiment was that the action of IOP could be attributed to its inhibition of conversion of T(4) to T(3). Although IOP is known to inhibit T(4) to T(3) conversion, the inhibition of cutaneous cell proliferation by IOP might conceivably result from other properties of IOP.

METHODS

In separate experiments, primary culture human keratinocytes and dermal fibroblasts were incubated overnight with IOP.

RESULTS

Proliferation was inhibited in a dose-dependent manner in both cell lines. Overnight incubation with T(3) restored the proliferation but overnight incubation with T(4) did not.

CONCLUSION

The study is the first to demonstrate that IOP inhibits cutaneous cell proliferation and that supplemental T(3) is sufficient to correct at least part of the inhibition caused by IOP. The data suggest that IOP decreases cutaneous cell proliferation by inhibition of intracellular T(4) to T(3) conversion. The data provide indirect evidence of the presence of type 1 or type 2 iodothyronine deiodinase activity in skin cells. The data support our previous hypothesis that T(3) is necessary for normal cutaneous proliferation.

A topical parathyroid hormone/parathyroid hormone-related peptide receptor antagonist stimulates hair growth in mice

One of the biggest hurdles in developing peptides for the treatment of hair growth disorders is that there has been no effective method of delivering them topically. Murine hair growth can be stimulated with ip injections of the PTH/PTHrP receptor antagonist, PTH (7-34). We sought to determine whether we could deliver PTH (7-34) topically and achieve stimulation of hair growth. We prepared a topical cream by mixing PTH (7-34) into a liposome vehicle (Novasome A). We applied the cream daily to the backs of 5-wk-old female SKH-1 hairless mice for 1 wk. After the 1 wk of treatment, there was marked stimulation of hair growth in the SKH-1 hairless mice. Relative to controls, mice treated with PTH (7-34) had 216% longer hairs (P < 0.001), 40% more visible hairs (P < 0.001), and 43% more hair follicles stained with 5-bromo-2'-deoxyuridine (P < 0.01). A unique aspect of skin is the possibility to directly target it via topical treatment. Our study is the first to report the hair-stimulating effect of a PTH/PTHrP receptor antagonist topically applied to skin in vivo. Thus, we introduce a novel paradigm to develop topical PTH analogs for treating disorders of hair growth.

AMPK regulation of the growth of cultured human keratinocytes

AMP kinase (AMPK) is a fuel sensing enzyme that responds to cellular energy depletion by increasing processes that generate ATP and inhibiting others that require ATP but are not acutely necessary for survival. In the present study, we examined the relationship between AMPK activation and the growth (proliferation) of cultured human keratinocytes and assessed whether the inhibition of keratinocyte growth by vitamin D involves AMPK activation. In addition, we explored whether the inhibition of keratinocyte proliferation as they approach confluence could be AMPK-related. Keratinocytes were incubated for 12 h with the AMPK activator, 5-aminoimidazole-4-carboxamide-1-beta-D-ribofuranoside (AICAR). At concentrations of 10(-4) and 10(-3) M, AICAR inhibited keratinocyte growth by 50% and 95%, respectively, based on measurements of thymidine incorporation into DNA. It also increased AMPK and acetyl CoA carboxylase phosphorylation (P-AMPK and P-ACC) and decreased the concentration of malonyl CoA confirming that AMPK activation had occurred. Incubation with the thiazolidinedione, troglitazone (10(-6) M) caused similar alterations in P-AMPK, P-ACC, and cell growth. In contrast, the well known inhibition of keratinocyte growth by 1,25-dihydroxyvitamin D3 (10(-7) and 10(-6) M) was not associated with changes in P-AMPK or P-ACC. Like most cells, the growth of keratinocytes diminished as they approached confluence. Thus, it was of note that we found a progressive increase in P-AMPK (1.5- to 2-fold, p < 0.05) as keratinocytes grown in control medium went from 25% to 100% confluence. In conclusion, the data are consistent with the hypothesis that activation of AMPK acts as a signal to diminish the proliferation of cultured keratinocytes as they approach confluence. They also suggest that AMPK activators, such as AICAR and troglitazone, inhibit keratinocyte growth and that the inhibition of cell growth by 1,25-dihydroxyvitamin D3 is AMPK-independent.

Topical thyroid hormone accelerates wound healing in mice

Although the physiologic role of thyroid hormone in skin is not well understood, mounting evidence suggests that T3 plays an important role in epidermal proliferation. The goal of this project was to evaluate whether the topical application of supraphysiologic doses of T3 could accelerate wound healing. We evaluated mice treated with topical T3 vs. the same mice receiving vehicle alone (Novasome A). Ten-millimeter diameter (79 mm2) dorsal skin wounds were established in all animals, and wounds were remeasured 4 d after injury. All animals were evaluated twice: once with the T3 treatment and once with the vehicle alone. Daily topical application of 150 ng T3 resulted in 58% greater wound closure relative to wounds on the same animals receiving vehicle alone (P < 0.001). Furthermore, we determined that wound healing-associated keratin 6 protein expression in hair follicle keratinocytes increased in a dose-dependent manner in vivo during topical T3 treatment. The data support our previous hypothesis that T3 is necessary for optimal wound healing. Now, we further suggest that topical thyroid hormone may be an inexpensive agent to hasten healing of certain wounds.

A role for thyroid hormone in wound healing through keratin gene expression

The importance of thyroid hormone (TH) in wound healing is not well understood. To gain insight, we evaluated the impact of TH deficiency on wound-healing genes in cultured keratinocytes. By RT-PCR, keratin 6a (K6a) and 16 (K16) gene expression in TH replete cells was 3.8- (P < 0.005) and 1.9-fold (P < 0.05) greater, respectively, than expression in TH-deficient cells. By real-time PCR, TH replete cell expression of K6a, K16, and K17 was greater than in deficient cells: 18- (P < 0.001), 10- (P < 0.001), and 4-fold (P < 0.005), respectively. To examine TH requirement for optimal wound healing, we contrasted TH-deficient vs. ip T(3)-treated mice. Four days after wounding, ip T(3)-treated mice had twice the degree of wound closure as hypothyroid mice (P < 0.001). By RT-PCR, K6a and K17 gene expression from control mouse skin was greater than from hypothyroid mouse skin: 5- (P < 0.001) and 1.7-fold (P < 0.05), respectively. T(3) is necessary for the keratinocyte proliferation required for optimal wound healing. T(3) exerts influence by stimulating expression of the wound-healing keratin genes. Thus, for hypothyroid patients undergoing surgery that cannot be delayed until euthyroidism is achieved, our data support T(3) treatment for the perioperative period.

Role for inner ring deiodination preventing transcutaneous passage of thyroxine

Creams containing thyroid hormone are commonly employed for cosmetic purposes. To verify whether T(4) applied to the skin surface can enter the bloodstream either directly or as a metabolite, a cream containing L-T(4) [3,5,3',5'-tetraiodothyronine (T(4))] was self-applied by volunteers for 2 wk. No significant variations in urinary iodide, TSH, and serum (total and free) T(4) and T(3) concentrations were observed at any time relative to pretreatment values, whereas rT(3) concentrations increased significantly 6 and 12 h after cream application. The increased rT(3) concentration led us to investigate the presence of inner ring type III deiodinase (D3) activity in human skin. Using human surgical discard skin, we found that T(4) can be carried across human epidermis in a liposome cream. Substantial inner ring deiodination was suggested by the fact that only 10% of transferred thyroid hormone remained as T(4), and T(3) was not detected. We then measured D3 activity in a surgical skin specimen. The K(m) for T(3) was 1.74 nmol/liter, and the maximum velocity was 23.5 fmol/microg microsomal protein/h. In conclusion, our study indicates that normal human skin serves as a substantial, but incomplete, barrier to T(4) passage. D3 plays an important role in augmenting T(4) blockade by inactivating T(4) to rT(3).

Thyroid hormone action on skin: diverging effects of topical versus intraperitoneal administration

Previously, we demonstrated stimulation of epidermal proliferation and hair growth in triiodothyronine (T(3)) treated mice. To distinguish skin effects of directly applied T(3) from those of systemic hyperthyroidism, we treated CD-1 mice with either intraperitoneally (IP) or topically administered T(3). Relative to controls, mice receiving T(3) IP had 10% thinner epidermis (p < 0.01) and 48% fewer hairs (p < 0.001). By contrast, mice receiving T(3) topically had 78% thicker epidermis (p < 0.01) and 160% more hairs (p < 0.01). To gain insight into factors responsible for the diverging effects, we contrasted T(3) effect on proliferation of isolated keratinocyte cultures versus keratinocytes cocultured with dermal fibroblasts. For keratinocytes grown in the absence of fibroblasts, T(3) stimulated proliferation in a dose-dependent, biphasic pattern with the peak at 0.5 nM T(3) (84 +/- 30%, p < 0.05). Paradoxically, T(3) inhibited proliferation of keratinocytes cocultured with fibroblasts, the nadir at 0.1 nM T(3) (34% +/- 4%, p < 0.001). These studies are the first describing divergent effects of IP and topically administered thyroid hormone. The data suggest that while T(3) stimulated keratinocyte proliferation, T(3) also stimulated proliferation inhibitory factor(s) from skin fibroblasts. Insight into the interplay among the competing factors will be important in understanding thyroid hormone regulation of skin physiology.

Adrenal metastasis secondary to papillary thyroid carcinoma

Differentiated papillary thyroid carcinoma is usually indolent. Distant metastases from papillary thyroid cancer are rare and associated with poor prognosis. To our knowledge there have been no reported cases of functioning adrenal metastases secondary to papillary carcinoma of the thyroid. Here we report a patient with papillary thyroid carcinoma where surveillance scanning with whole-body 131I scan revealed a large, solitary adrenal metastasis. A 73-year-old woman was treated aggressively for a large papillary thyroid carcinoma. After fine-needle aspiration biopsy of the thyroid nodule, she underwent near-total thyroidectomy and postoperative treatment with 150 mCi of 131I. Nine months later, surveillance whole-body 131I scanning revealed a large focus of uptake in the right adrenal gland. The patient underwent adrenalectomy and a papillary thyroid carcinoma metastasis was confirmed. To our knowledge this is the first description of a functioning papillary thyroid carcinoma metastatic to the adrenal.