Citations

Abstract Disclosure: M. Sokrab: None. V.S. Rao: None. P. Shah: None. J.L. Shaker: None. A 47 year-old woman was evaluated 2/2024 for bone pain especially in the forearms and lower legs. The symptoms were worse since about 4/2023. Initial evaluation 11/2023 revealed elevated alkaline phosphatase levels and markers of bone remodeling (P1NP 396 ug/dl, normal; 20-101 and C-telopeptide 4389, normal; 177-1015. The plasma fluoride level was 17.1 mcmol/L (normal; < 4.1). There was no history of excess exposure to fluoride from dental products. She did not drink powdered iced tea or use green tea capsules. There was no industrial fluoride exposure and she consumed city water. She used inhaled fluticasone twice weekly but was not taking other fluoride containing medications, particularly voriconazole. She reported huffing computer cleaner containing difluoroethane between mid 2023 and early 2024. On examination, she had diffuse skeletal tenderness especially over her forearms and lower legs. Lab data revealed calcium 9.2 mg/dl (normal, 8.6-10.2), albumin 4 g/dl, phosphorus 3.6 mg/dl (normal, 2.5-4.5), creatinine 1.08 mg/dl (normal, 0.5-1.1), ionized calcium 1.33 mmol/l (normal, 1.18-1.33), pH normalized ionized calcium 1.25 mmol/l (normal, 1.18-1.33), PTH 126 pg/ml (normal, 15-72), 25(OH)vitamin D 29.5 ng/ml (normal, 20-50), and alkaline phosphatase 287 u/l (normal, 40-120) with a predominant elevation of the bone isoenzyme. The bone specific alkaline phosphatase was 93.4 mcg/l (normal, 7.0-22.4). The SPEP revealed a biclonal IgG Kappa monoclonal protein too small to quantify. The repeat fluoride level was 1.2 mg/l (normal, <0.05). Imaging included diffuse uptake on bone scan as well as periostitis/periosteal thickening involving legs, arms, and hands. There was axial osteosclerosis. Our patient appears to have skeletal fluorosis. Although the time-line of reported huffing and symptoms is not completely consistent, we could find no other exposure to fluoride and speculate she may have been huffing before she recalls. Skeletal fluorosis (SF) is endemic in some countries generally related to drinking water or tea that is high in fluoride, In the US, SF is caused by abnormal use of fluoride-containing dental products, excessive consumption of powdered iced tea containing fluoride, chronic use of the antifungal agent voriconazole and now more often huffing abuse of computer cleaners containing difluoroethane. The number of reported cases of huffing-related SF appears to be increasing and greater awareness of this problem is needed. Presentation: 6/1/2024

Abstract Disclosure: A.L. McKenna: None. Y. Huang: None. L. Yang: None. N. Loo: None. C. Ritchie: None. A. Metcalfe: None. R. Nakhleh: None. M. Krishna: None. S. Thota-Kammili: None. J. Eleazer: None. A.Y. Chang: None. Hepatocellular adenomas (HCA) are uncommon, benign epithelial tumors of the liver. Risk factors include exogenous estrogen or androgen use, and genetic and metabolic syndromes. Management of HCA is delineated by sex assigned at birth; Observation is recommended in an HCA less than 5 cm in an individual assigned female at birth, while resection of an HCA in an individual assigned male at birth is recommended no matter the size due to risk of malignant transformation. What is not known is whether risk is different for individuals with gender incongruence on gender affirming hormone therapy (GAHT). There is limited data on the risk of HCA in this population. One case report of a transgender man who continued GAHT after diagnosis of an HCA though no follow-up information was available. We present follow-up on a transgender man assigned female at birth with multiple hemorrhagic HCA that was re-initiated on GAHT after stabilization of adenomas off GAHT. Unlike prior cases, the molecular profile showed ß-catenin negative, estrogen and androgen receptors positive. This is the first case report to our knowledge reporting detailed follow-up after restarting masculinizing GAHT after diagnosis of HCA. A 24-year-old transgender man presented to the emergency department with right upper quadrant pain. Initial labs were notable for ALT of 239 units per liter (U/L) and AST 165 U/L. Magnetic resonance imaging (MRI) of the abdomen and liver elastogram revealed multiple bilobar hepatic masses, the largest measuring 9.9 cm concerning for hemorrhagic HCA which was subsequently confirmed on liver biopsy. Immunostains were positive for estrogen and androgen receptors. The patient had no history of alcohol or illicit drug use, tattoos, or family history of liver disease. The patient had been treated with 100 mg of intramuscular testosterone cypionate weekly for the past six years for gender incongruence locally. No testosterone concentrations were available from prior to or during acute presentation. Discontinuation of hormone therapy was recommended along with conservative management with frequent MRI. Over the next 19 months, monitoring revealed improvement/resolution of the auto infarcting adenomas with the last MRI noting two stable HCA measuring 2.1 cm and 0.8 cm without new or enlarging liver lesions. Due to gender dysphoria off GAHT, reinitiation of hormone therapy with low dose AndroGel 1.62% topically was prescribed at 18 months after presentation. The patient has been monitored with labs monthly and plans to obtain MRI abdomen every three months. To date, the patient has tolerated reinitiation of therapy. This case demonstrates that patients on masculinizing GAHT who develop HCA can be conservatively managed and monitored based on pathology and that testosterone does not necessarily explain sex differences in the presentation/malignant transformation of HCA cisgender men as opposed to cisgender women. Presentation: 6/3/2024

Abstract Disclosure: D. Toro-Tobon: None. H. Billings: None. I. Bancos: None. Background: Mentorship is crucial for training physicians' career development, yet evidence of its impact on endocrinology trainees is lacking. We assessed the current state of mentorship in endocrine fellowship training in the United States. Methods: We conducted a cross-sectional study between June and September 2023. Endocrine fellows were invited to complete an online questionnaire describing their mentorship experience and its influence on burnout, satisfaction, and scholarly productivity. Results: Of 153 participants (mean age 34, 69% women, 47% White, 20% Hispanic/Latino), 73% had a mentor. Having a mentor was not associated with age, gender identity, race, or ethnicity. Those without mentors were more commonly in two-year fellowships (63% vs. 81%, p=0.04), had less access to formal mentorship programs (48% vs. 21%, p<0.01), cited insufficient faculty availability for mentoring (11% vs. 26%, p=0.01), and encountered more challenges finding mentors in their training programs (11% vs. 38%, p<0.001). Mentored participants exhibited increased post-fellowship interest in academic practice (69% vs. 50%, p<0.01), higher involvement in clinical research (65% vs. 49%, p=0.01), more fellowship-dedicated scholarly time (36% vs. 22%, <0.001), a greater median number of publications (4.6 vs. 1.8, p<0.01) and abstracts (7 vs. 3.7, p<0.01), were more likely to have submitted a grant (29% vs. 5%, p=0.03) and had higher satisfaction with training (92% vs. 64%, p<0.001). Mentors were mostly chosen by mentees (70%) and shared gender identity (61%) but often had a different race or ethnicity (71.8%). The majority found mentorship relationships satisfactory (87%), contributing to increased academic productivity (84%) and reduced mentee burnout and stress levels (60%). In bivariate analysis, all mentor attributes significantly influenced higher academic productivity and mentee satisfaction. The most divergent for academic productivity were improved communication, alignment with expectations, inspiration for goal attainment, and effective networking. For mentorship satisfaction, distinctions were found in communication enhancement, goal-oriented assistance, knowledge/skill enrichment, and personalized career path development. Traits like active listening and adapting communication styles were not linked to decreased burnout, but actively supporting work-life balance independently correlated with reduced burnout. Conclusion: Mentorship positively affects endocrine fellows' scholarly productivity and career development. Yet, a significant number lack mentors or access to programs. Mentor attributes, like effective communication, goal alignment, and networking support boost productivity and satisfaction. However, reducing mentee burnout hinges on actively fostering work-life balance. Presentation: 6/3/2024

Abstract Disclosure: B.M. Biller: Consulting Fee; Self; HRA Pharmaceuticals, Novartis Pharmaceuticals, Sparrow, Strongbridge Biopharma. Grant Recipient; Self; Strongbridge Biopharma. A. Gilis-Januszewska: Speaker; Self; Ipsen, Novartis Pharmaceuticals, Novo Nordisk, Recordati, Teva Pharmaceutical Industries Ltd.. M. Doknic: None. A.M. Pico: None. M. Fleseriu: Consulting Fee; Self; Ascendis, GlaxoSmithKline, Johnson &Johnson, Karyopharm, Novo Nordisk, Pfizer, Inc., Pharmacosmos. Research Investigator; Self; Ascendis. G. Raverot: None. A.M. Isidori: None. Y. Takahashi: None. J.M. Garcia: None. J.M. Silverstein: None. I. Bancos: None. E. Huang: Employee; Self; Ascendis Pharma, Inc. J. Kang: Employee; Self; Ascendis Pharma, Inc. A.S. Komirenko: Employee; Self; Ascendis Pharma, Inc. L. Domrzalski: Employee; Self; Ascendis Pharma, Inc. A. Shu: Employee; Self; Ascendis Pharma, Inc. K. Yuen: Advisory Board Member; Self; Amryt, Ascendis, Corcept, Crinetics, Novo Nordisk, Recordati, Strongbridge, Xeris. Grant Recipient; Self; Amryt, Ascendis, Corcept, Crinetics. Speaker; Self; Corcept, Novo Nordisk, Recordati. Background: Adult GHD (aGHD) is characterized by metabolic abnormalities due to insufficient growth hormone (GH) production. Lonapegsomatropin was designed to provide sustained release of unmodified somatropin, with the identical amino acid sequence as endogenous GH, and once-weekly injection reduces the burden of daily GH replacement therapy. MethodsForesiGHt was a randomized, parallel-3-arm, placebo(PL)-controlled (double-blind) and active-controlled (open-label) trial designed to establish the efficacy and safety of lonapegsomatropin in aGHD. It evaluated 259 adults with GHD across 21 countries who were GH treatment-naïve or not treated with GH in the prior year, randomized 1:1:1 to receive lonapegsomatropin, once-weekly PL, or daily somatropin (dGH). Fixed dosing was based on age and oral estrogen intake, and designed to be comparable across lonapegsomatropin and dGH arms. Following a 12-week (w) titration period to target maintenance dose, fixed doses were administered for 26w. ResultsBaseline (BL) characteristics were similar between arms. Lonapegsomatropin demonstrated superiority on the primary efficacy endpoint of change from BL in trunk percent fat at Week 38 vs PL (lonapegsomatropin -1.7% vs PL 0.4%, LS mean difference -2.0%, p < 0.0001) and on the key secondary efficacy endpoints of change from BL in total body lean mass (lonapegsomatropin 1.6 kg vs PL -0.1 kg, LS mean difference 1.7 kg, p < 0.0001) and change from BL in trunk fat mass (lonapegsomatropin -0.5 kg vs PL 0.2 kg, LS mean difference -0.7 kg, p = 0.0053). Mean total exposure and maintenance doses were similar for lonapegsomatropin and dGH arms, with larger changes from BL in average IGF-I SDS mean at Week 38 in the lonapegsomatropin arm (1.4) vs dGH arm (0.5). To assess outcomes at comparable weekly IGF-I exposure, a post-hoc analysis was performed in a subset of participants with average IGF-I SDS ≤1.75 SDS at Week 38. Mean IGF-I SDS for these subsets were similar (lonapegsomatropin -0.1, dGH -0.5), and comparable effects in fat and lean tissue compartments were demonstrated (change from BL in trunk percent fat mean -2.4% and -2.6% respectively; change from BL in total body lean mass mean 1.7 kg and 1.4 kg respectively). In the safety population, the incidence of severe AEs was low (lonapegsomatropin, 3.4%; placebo, 1.2%; dGH, 2.3%) and the incidence of treatment-related AEs was similar (lonapegsomatropin 24.7%, dGH 22.1%). Injection site reaction incidence was low and similar for lonapegsomatropin (4.5%), dGH (5.8%) and placebo (4.8%), and A1c levels remained stable in all treatment arms. ConclusionsThe results of the foresiGHt trial indicate that lonapegsomatropin is a safe, efficacious, and tolerable replacement for endogenous GH. Once-weekly dosing may be impactful for adults with GHD who typically manage multiple other medical therapies. Presentation: 6/3/2024

Abstract Disclosure: V. Adedara: None. K. Maddineni: None. A. Dekhne: None. M. Chinthapalli: None. G. Potluri: None. A. Parisapogu: None. K. Markandu: None. H. Desai: None. Background: Ischemic Heart Disease (IHD) stands as the foremost cause of mortality globally, contributing to 9.6 million deaths. Elevated levels of low-density lipoprotein cholesterol (LDL-C) consistently feature among the risk factors associated with IHD. Methods: Employing the Global Burden of Disease framework, we computed mortality and DALYs linked to IHD attributable to LDL-C, stratified by age-sex, year, and covering 204 countries and territories during the period from 1990 to 2019. Non-fatal health outcomes were estimated using DISMOD MR 2.1, Bayesian meta-regression tool for epidemiological modelling. Results were expressed in absolute counts and age-standardized rates (ASR) per 100,000 person-years. Results: The total number of deaths attributed to IHD due to elevated LDL-C increased from 2.5 million (95% Uncertainty Interval: 2-3.1 million) in 1990 to 3.7 million (95% UI: 2.8-4.8 million) in 2019. Concurrently, DALYs increased from 60.4 million (95% UI: 50.4-70.7 million) in 1990 to 84.9 million (95% UI: 69.5-101.3 million) in 2019. In terms of ASR, the annual percentage change (APC) in death rates decreased by 36%, and DALY rates decreased by 32% from 1990 to 2019. Regionally, East Asia exhibited the highest increase in APC in death counts by 191%, followed by Commonwealth Low-Income countries at 164%, and Oceania at 160% during the same period. Conversely, the Commonwealth High-Income region experienced the highest decrease at 41%. Males displayed higher APC in death (48% vs. 44%) and DALYs (42% vs. 38%) compared to females over the last three decades. In terms of ASR, males observed a higher decrease compared to females. In 2019, the age group 80-84 years had the highest number of deaths at 534,079 (264,177-813,898), while DALYs were most pronounced in the 55-59 year age group, reaching 10.6 million (8.9-12.3 million). Conclusion: IHD remains a significant global health challenge, with high LDL-C levels being a crucial modifiable risk factor. Age-sex disparities in the burden of IHD are evident, driven by variations in LDL-C metabolism, hormonal changes, and lifestyle factors. Recognizing and addressing these disparities is essential for developing effective prevention and treatment strategies tailored to different populations and age groups. Presentation: 6/2/2024

Abstract Disclosure: D. Segura Torres: None. K. Raygoza: None. M. Garcia: None. J.P. Brito: None. M.E. McDonnell: None. M. Corrigan: None. C.R. McCartney: None. R. Dhaliwal: None. N.M. Singh Ospina: None. Clinical practice guidelines (CPG) improve healthcare quality by guiding decision making. Recent trends in CPG development emphasize incorporating race/ethnicity terms and health equity considerations. However, the appropriateness of how race/ethnicity is utilized remains uncertain. Objective This study seeks to evaluate the use of race/ethnicity in published Endocrine Society (ES) CPG and elucidate the context in which race and ethnicity terms are used. Methods: We identified 30 active clinical practice guidelines from ES up to January 2023. Two reviewers independently and in duplicate: a) located statements addressing race/ethnicity using an electronic search with 24 keywords, b) determined the statements' location within guidelines, and c) classified them based on content using frameworks by Cerdena and Gilliam. Disagreements were resolved by consensus. Exclusions were made for statements not addressing race and ethnicity terms in the appropriate context (e.g., “minority” of the panel disagreed), as well as for those in references or duplicates. Results: We reviewed 30 clinical practice guidelines, with 19 of them containing statements related to race or ethnicity. After applying exclusion criteria, we identified a final analytic sample of 114 statements. The majority of these statements were found in the body of the clinical guidelines (79%), followed by the evidence-to-decision framework (14%), and clinical recommendations (7%).The predominant classification were statements in which there was biologization of race/ethnicity 55% (n=63). Discussions on racial/ethnic disparities accounted for 23% (n=26) of the statements, with 31% (n=8) of these including explicit considerations of social context. Additionally, there were descriptions of race-specific treatment or diagnosis/screening in 14% (n=16) and 9% (n=10) of the statements, respectively.Less commonly statements of race/ethnicity reflected the consideration of ancestry as a code for race/ethnicity (n=7, 6%), identified ancestry as a risk factor for disease (n=19, 6%), highlighted racial/ethnic groups as understudied n=6, 5%), normalized findings to the majority group (White centeredness) (n=7, 6%), and other categories (7%). None of the statements employed race/ethnicity terms to emphasize cultural humility or the value of inclusivity in guideline committees. Conclusion: We systematically analyzed how race and ethnicity terms are used in ES CPGs. Our findings align with prior assessments made in non-ES CPG, highlighting the prevalent biologization of race and ethnicity constructs. Addressing this trend and incorporating socio-structural context considerations could bolster the impact of clinical guidelines in promoting health equity. Presentation: 6/1/2024

Abstract Disclosure: K.N. Rachmasari: None. A. Osman: None. D. Toro Tobon: None. S.B. Lund: None. D.J. Merlino: None. A.R. Hsu: None. M.M. Ryder: None. Background: In low-risk papillary thyroid cancer (PTC), radioactive iodine (RAI) remnant ablation has shown no impact on disease recurrence rates, which are overall low. The role of adjuvant RAI in intermediate risk disease (i.e. T3, N1) remains unproven with no randomized clinical trials to objectively assess efficacy. Thus, in our institution, its use is highly heterogenous. We retrospectively investigated the effects of adjuvant RAI on recurrence and recurrence free survival (RFS) in patients with PTC and positive cervical lymph nodes (CLN). Methods: We performed a retrospective review of patients who underwent surgery at Mayo Clinic Rochester, MN for PTC between January 2007 and December 2016. Adult patients with Tx-T3 disease according to the 8th edition of American Joint Committee on Cancer (AJCC) were identified. Patients with positive CLN (N1) and a minimum follow up of 36 months were included. Demographics, clinicopathologic characteristics, use of RAI therapy and recurrence were analyzed. Results: A total of 367 patients with PTC, Tx-3, N1, M0 were identified, of which 187 received adjuvant RAI and 180 did not. Most patients were female (63.8%), with a median age of 44 years (IQR 34-54), and a median follow up of 77 months (IQR 58.5-101.5). There were no differences in age, type of surgery, histology, multifocality, and follow up period between the RAI and no RAI subgroups. Adjuvant Thyrogen-stimulated or thyroid hormone withdrawal-based RAI was recommended at the discretion of the treating provider and/or per patient preference. Diagnostic I-123 whole body scans were performed in all patients and mostly demonstrated remnant uptake. The median dose of I-131 was 75 mCi (range 50-100). Recurrence was defined by new occurrence of disease after at least a year of absence of clinical, biochemical, and imaging evidence of disease since initial surgery. Within the entire cohort, 35 (9.5%) developed recurrence with a median time of 41 months (28-59.5). Overall, recurrence rate and RFS were not significantly different between both subgroups (p = 0.2). A subanalysis was performed in patients with clinically detectable nodal disease (n = 161), defined by abnormal cervical lymph node on preoperative neck ultrasound with or without positive fine needle aspiration biopsy. Overall recurrence rates were 17 (10.6%) in this group. There were no differences in recurrence rates and RFS in those that received RAI versus those that did not (p = 0.8). Conclusions: In patients with intermediate risk PTC defined by nodal disease and/or T3 disease, recurrences were not different between patients that did or did not receive adjuvant I-131 therapy postoperatively. A randomized, noninferiority study of adjuvant I-131 compared to no I-131 postoperatively for N1 disease is needed to determine the benefit of near total thyroidectomy and adjuvant I-131 for this cohort. Presentation: 6/3/2024

Abstract Disclosure: S. Ahmed: None. M. Vahidi Rad: None. S.A. Westphal: None. M.D. Whitaker: None. Introduction: Painful Hashimoto thyroiditis is a rare variant of Hashimoto thyroiditis that mostly affects women. Most cases are empirically treated as subacute thyroiditis with corticosteroids, levothyroxine, or nonsteroidal anti-inflammatory drugs. However, no medical treatment may provide sustained pain resolution, so optimal treatment remains unclear. We describe the case of a 40-year-old female with longstanding throbbing anterior neck discomfort that failed medical therapy and her symptoms completely resolved with total thyroidectomy. Case Report: A 40-year-old lady with anterior neck pain centered over the thyroid for more than 16 years, shortly after she delivered her last child. The pain is described as intense, it tends to wax and wane but there is a constant throbbing with occasional radiation to the angle of the jaw. Over the years the pain has gradually worsened and during its flares, the thyroid itself is very tender to the point where she experiences difficulty in swallowing and hoarseness of voice. Complicating the issue is her underlying diagnosis of fibromyalgia, as she tends to experience discomfort in many other areas of her body. However, the neck pain appears to be of a different character. No symptoms of hyper or hypothyroidism. The anterior neck pain has been difficult to alleviate, she has used chronic opioids for it which seems to have helped to some extent, in the past she was on prednisone for 1 month however this made no difference to it. On examination, the thyroid is tender and somewhat firm without lymphadenopathy. Thyroid levels have been consistently normal and the most recent of which was a TSH: 1.48, FT4: 1.4, FT3: 3.5 with negative TPO and thyroid stimulating antibodies. ESR and CRP were unremarkable. Thyroid ultrasound showed mildly heterogeneous parenchyma with no solid nodules or lymphadenopathy. Interestingly she had an elevated thyroid uptake in her scan dated April 1st 2022, 4 hour and 24-hour uptakes were abnormal at 23% and 49% respectively which can be seen with Hashimoto's. She underwent total thyroidectomy and her surgical pathology showed benign thyroid tissue with multiple foci of chronic lymphocytic thyroiditis and hyperplastic nodules. Her pain completely resolved after total thyroidectomy. Discussion: Painful Hashimoto thyroiditis is a rare diagnosis and optimal treatment remains unclear. The painful variant of Hashimoto's thyroiditis should be considered in the differential diagnosis of pain and tenderness of the thyroid which can be managed successfully by surgical treatment. Thyroidectomy not only can lead to alleviation of symptoms but also provides the definitive diagnosis. The risks of surgical intervention must be taken into consideration, especially because painful Hashimoto thyroiditis can be associated with a small fibrous gland; hence, the importance of access to highly skilled, experienced surgeons cannot be overemphasized. Presentation: 6/1/2024

Abstract Disclosure: K. Yu: None. J. Saini: None. J.N. Farr: None. F. Vanessa: None. S. Khosla: None. I. Bancos: Advisory Board Member; Self; AstraZeneca, Adrenas, Neurocrine, Spruce, Recordati, Xeris, Novo Nordisk, HRA Pharmaceuticals, Sparrow, Diurnal, Corcept. Research Investigator; Self; HRA Pharmaceuticals, Recordati. Importance: Patients with both mild autonomous cortisol secretion (MACS) and overt Cushing syndrome (CS) demonstrated high prevalence of aging-related morbidity and an increased mortality. Objective: To determine whether p16INK4a in T cell, a cell cycle enzyme that associated with chronological aging and cell senescence, is associated with hypercortisolism and hypercortisolism-related comorbidities. Design, Setting, and Participants: In this single-center cross-sectional study, we prospectively recruited consecutive patients with hypercortisolism between July 1, 2020 and August 24 2022. Patients were included if they were diagnosed with Cushing syndrome (CS) or mild autonomous cortisol secretion (MACS). Age- (± 2 years) and sex-matched referent subjects without known adrenal disorders were included if abdominal imaging was available. Participants on exogenous glucocorticoids within 3 months prior were excluded. Exposure: Presence of hypercortisolism (MACS and CS). Main Outcomes and Measures: Primary outcomes included p16INK4a, advanced glycation end products (AGE) reader result, Frailty Index score, frailty (defined as frailty index>0.31), and physical performances in patients and matched referents at index date. Secondary outcomes included correlation between biological age markers, hormonal workup and the risk of comorbidities. p16INK4a expression analysis was adjusted for age, sex, smoking, and alcohol use for all analyses except for associations with CVD and frailty. Results: Of 85 patients (87% women, mean age 53 years), 51 (60%) had MACS (34 had matched referents), 34 (40%) had overt CS (16 had matched referents). Patients with CS demonstrated a median 1.9-fold higher p16INK4a expression (P<.001), and patients with MACS showed a median of 1.70-fold p16INK4a expression (P=.013), when compared to referent subjects. Age- and sex-adjusted p16INK4a expression was associated with frailty index score (r=0.23, P=.035), time-up-and-go test (r=0.28, P=.048), gait speed (r=-0.36, P=.035), but not with AGE reader result, 6-minute walk test, or hand grip measurement. The p16INK4a expression was associated with history of cardiovascular disease (age-adjusted odds ratio (aOR)=3.70, 95% confidence interval (CI), 1.20-11.43) and frailty (aOR=2.27, 95%CI, 1.04-4.98). Conclusion and relevance: We demonstrated evidence of cell senescence in both patients with CS and patients with MACS. Further studies need to determine the impact of surgical, cortisol-lowering, and senolytic medical therapies in MACS on cell senescence and associated aging-related comorbidities. Presentation: 6/1/2024

Abstract Disclosure: C.A. Conover: None. L.K. Bale: None. D. Hamadi: None. M. Stan: ; Tourmaline, Genentech, Third Rock Ventures, ArgenX, Septerna, OrthoDi. ; Horizon, Immunovant, Lassen, Sling. Background: Proptosis in Thyroid Eye Disease (TED) can result in facial disfigurement and visual dysfunction. Studies revealed an interaction between thyroid-stimulating hormone receptor (TSHR) and insulin-like growth factor-I receptor (IGF-IR) that is essential in promoting TED pathogenesis. Treatment with Insulin-like growth factor I receptor (IGF-IR) inhibitors has been shown to be effective in reducing proptosis but with side effects. PAPP-A is metalloprotease that can increase pericellular IGF bioavailability through specific cleavage of inhibitory IGF binding proteins, in particular IGFBP-4. We propose that inhibition of IGF-IR indirectly and more selectively with PAPP-A inhibitory antibodies attenuates IGF-IR signaling in TED with fewer side effects. Methods: Informed consent was obtained from TED patients undergoing surgery in Mayo Clinic operating suites in Rochester, MN. Retro-orbital tissue was collected from 19 TED patients and 2 control subjects for fibroblast isolation and culture and was performed in a sterile tissue culture facility. TED and control fibroblasts were treated with pro-inflammatory cytokines, and flow separation of CD34- and CD34+ orbital fibroblasts was done, the latter representing infiltrating fibrocytes into the orbit in TED. Main outcome measured were PAPP-A expression and proteolytic activity, IGF-I stimulation of phosphatidylinositol 3 kinase/Akt pathway and inhibition by immuno-neutralizing antibodies against PAPP-A, CD34+ status and associated PAPP-A and IGF-IR expression. Results: Primary cultured cells showed that PAPP-A is expressed in orbital fibroblasts from TED patients but not in control subject fibroblasts and were markedly increased by pro-inflammatory cytokines stimulation. IGF-IR expression was not affected by cytokine treatment. Inhibition of PAPP-A’s proteolytic activity suppressed IGF-IR activation in orbital fibroblasts from TED patients. CD34+ orbital fibroblasts represent 80% of cells in culture from TED patients, and approximately 70% of these cells were accountable for PAPP-A and IGF-IR expression. Conclusion: These results support a role for PAPP-A in TED pathogenesis and indicate the potential for novel therapeutic targeting of the IGF axis. Presentation: 6/2/2024