Citations

Introduction: Vitamin D is an essential micronutrient for infant calcium metabolism and bone development. Concentrations of vitamin D in breastmilk are low, despite higher anti-rachitic activity and correlations between infant and maternal serum 25-hydroxyvitamin D (25D) (Taylor, et al., 2008; Oberhelman, et al., 2013). The sulfate-conjugated form of 25D is present in blood at concentrations approximately 40% of unmodified 25D. We hypothesized that sulfate conjugates, vitamin D3-sulfate (VitD-S) and 25-hydroxyvitamin D3-sulfate (25D-S), are present in milk and increase during supplementation. The objectives are (1) developing an LC-MS/MS assay to quantify VitD-S and 25D-S in milk, and (2) determine if these vitamin D sulfates increase with daily vitamin D supplementation. Methods: An LC-MS/MS method was developed to measure VitD-S and 25D-S in milk and in serum. Standards (Toronto Chemicals, Toronto, ON, CA) and internal standard (Glycomyr, Ames, IA) were used to optimize methods. Briefly, Milk (500 uL) and serum (250 uL) were extracted with methanol (MeOH) and resuspended in 150 uL 70% MeOH. Analytes were separated by C18 column with 70% to 100% MeOH with ammonium acetate (NH4OAc) organic phase gradient followed by MS/MS with optimized mass transitions and ESI in negative mode on SCIEX API 5000. An ongoing study is under way for breastmilk and serum collections from healthy lactating women consuming <600 IU vitamin D3/day at enrollment (day 1) and after 28 days of oral 5000 IU vitamin D3/day (day 28). This study was approved by the Mayo Clinic Institutional Review Board. Results: Preliminary analyses have been completed for 3 study participants. Serum 25D status had a trending increase from 30±2 ng/mL 25D on day 1 to 40±2 ng/mL 25D on day 28 ( P=0.1, paired t-test). Limit of detection [signal to noise (s/n) >3] for sulfates were 0.5 ng/mL 25D-S (s/n=7.3) and 0.25 ng/mL VitD-S (s/n=6.2). Upon enrollment, breastmilk sulfates were 3.25±0.12 ng/mL VitD-S (s/n=83.7±20.6) and 0.18±0.02 ng/mL 25D-S (s/n=13.6±3.3), and serum sulfates were 7.5±0.8 ng/mL VitD-S (s/n=39.4±22.5) and 53.2±10.4 ng/mL 25D-S (s/n=22.5±7.2). No statistical differences were observed between day 1 and day 28 in milk or serum sulfates for the 3 participants. However, VitD-S concentrations demonstrated a significant negative correlation between serum and milk ( r=0.87, P=0.03), and serum 25D-S was 21.3 ng/mL greater than unmodified serum 25D ( P=0.009, n=6). This study is ongoing, and data presented will include a greater number of study participants. Conclusions: We have developed an LC-MS/MS assay to measure VitD-S and 25D-S and found that VitD-S and 25D-S are present in freshly expressed breastmilk and in serum from women consuming <600 IU vitamin D3/day. F32 DK128987 & The Mayo Clinic Parker D. Sanders & Isabella G. Sanders Endowed Professorship. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Overfeeding and fasting both increase circulating free cortisol levels and appear to alter the balance between cortisol and its inactive metabolite, cortisone. The effect of fasting on free cortisol levels is modified by sex. Further study is needed to determine the mechanisms driving the increases in cortisol.

Abstract Introduction: We performed matched case-control studies utilizing cohorts of postmenopausal women with ER+ breast cancer receiving adjuvant aromatase inhibitors (AI) on MA.27 [anastrozole, exemestane] or PreFace [letrozole] to assess the association between estrogen suppression after 6 months of treatment and an early breast cancer (EBC) event within 5 years of AI initiation (Clin Cancer Res 2020;26:2986-98). We found a significant 3.0-fold increase in risk of an EBC event for those taking anastrozole with levels of estrone (E1) ≥1.3 pg/mL and estradiol (E2) ≥0.5 pg/mL, but not for exemestane or letrozole. Given these findings we designed a prospective pharmacodynamic (PD) study to evaluate the impact of anastrozole (1 mg/day: ANA1) on E1 and E2 levels, and among those with inadequate estrogen suppression (IES: E1 ≥1.3 pg/mL and E2 ≥0.5 pg/mL), to evaluate the safety and PD efficacy of high-dose anastrozole (10 mg/day: ANA10), which has been found to be safe in prior clinical trials (Cancer 1998;83:1142-52). Methods: Post-menopausal women with stage I-III, ER ≥1% positive/HER2-negative breast cancer who were candidates for anastrozole were eligible after completion of locoregional therapy and chemotherapy, as clinically indicated. Women who were pre-menopausal at diagnosis were not eligible. All patients received 8-10 weeks of ANA1, after which those with adequate estrogen suppression (AES: E1&lt; 1.3 pg/mL or E2&lt; 0.5 pg/mL) came off study. Those with IES went on to receive ANA10 for 8-10 weeks, followed by letrozole (2.5 mg/day: LET) for 8-10 weeks. All patients were managed at their treating oncologist’s discretion following study discontinuation. E1 and E2 blood levels were measured pre-treatment and after completion of each treatment cycle by a CLIA-approved liquid chromatography with tandem mass spectrometry in the Immunochemical Core Laboratory at Mayo Clinic. With a sample size of 29 patients with IES after ANA1, a one-sided binomial test of proportions with a significance level of 0.05 will have an 87% chance of rejecting the proportion with AES after ANA10 is at most 25% (Ho) when the true proportion is at least 50%. Specifically, the null hypothesis is rejected if the number of women with AES after ANA10 is 12 or more. Data lock was July 6, 2022. Results: Of the 161 women enrolled from April 2020 through May 2022, 3 withdrew consent prior to start of ANA1 and 2 were ineligible; thus, 156 women comprised the study cohort. Median patient age was 64 years (range 44-86), 10% of patients were of Hispanic ethnicity and/or non-white race, and 15% received chemotherapy. Six patients remain on ANA1, and 10 discontinued ANA1 due to refusal (7), adverse event (AE) (2), or COVID-19 (1). Forty-one of the remaining 140 patients (29.3%; 95%CI: 21.9-37.6%) had IES with ANA1. Nine of these 41 patients did not go on to ANA10 due to refusal (6) or AE (3). Of the 32 patients who started ANA10, 8 remain on treatment, 5 discontinued due to refusal (3) or AE (1-grade 2 urinary tract infection; 1-grade 1 palpitations), and 19 had a blood draw 45 days or more after starting ANA10. No grade 3-5 AEs or grade 2 hot flashes or arthralgias were reported. Of these 19 patients, 14 achieved AES with ANA10 (73.7%; 95%CI: 48.8-90.9%). All 19 patients switched to LET of which 3 remain on treatment, 1 is missing E1/E2 data, and 15 had a blood draw 45 days or more after starting LET. Of these 15 patients, 10 maintained AES, 2 acquired AES with LET, and 3 no longer had AES. Anastrozole and letrozole drug levels will be reported at the meeting. Conclusions: Approximately 29% of postmenopausal women with ER+/HER2- BC receiving adjuvant anastrozole 1 mg/daily had IES. A majority of these patients achieved AES with dose escalation to ANA10 without tolerability issues. E1 and E2 levels are logical biomarkers given the mechanism of action of anastrozole, and further study utilizing them to determine the optimal dose of anastrozole for a given patient should be performed. Citation Format: Tufia C. Haddad, Vera Suman, Karthik V. Giridhar, Alvaro Moreno-Aspitia, Donald Northfelt, Brenda Ernst, Kostandinos Sideras, Ciara C. O’Sullivan, Ravinder Singh, Zeruesenay Desta, Jodi Taraba, Barbara Goodnature, Matthew P. Goetz, Liewei Wang, James N. Ingle. Anastrozole dose escalation for optimal estrogen suppression in postmenopausal early stage breast cancer: A prospective trial [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr OT1-04-02.

Objectives Chronic pancreatitis (CP) is a chronic fibroinflammatory condition of the pancreas difficult to diagnose in early stages. Novel biomarkers useful to facilitate early diagnosis or treatment responses may be found in biofluids. Although saliva can be easily and noninvasively collected from patients, useful salivary biomarkers from CP patients have not yet been identified. Methods Here, we analyzed the proteome by quantitative proteomics, cytokine/chemokine levels by Luminex analysis, prostaglandin E2 (PGE2) levels by a mass spectrometry-based assay, and bacterial species diversity by 16S ribosomal ribonucleic acid sequencing in saliva samples from confirmed CP patients and healthy controls. Results Our results indicate the presence of various differentially expressed proteins, cytokines/chemokines, and a loss of oral bacterial diversity in the saliva of CP patients. The PGE2 levels trend toward elevation in CP patients. Area under the receiver operating characteristic curve models for proteomic, cytokine, and PGE2 assays ranged from 0.59 to 0.90. Conclusions Collectively, our studies identify a range of putative CP biomarkers and alterations in human saliva requiring further validation. The biomarker discovery approaches we used might lead to identification of biomarkers useful for CP diagnosis and monitoring.

Background: There is limited long-term follow-up of patients undergoing parathyroidectomy. Recurrence is described as 4% to 10%. This study evaluated persistence and recurrence of hypercalcemia in primary hyperparathyroidism after parathyroidectomy. Methods: Single-institution retrospective (1965–2010) population-based cohort from Olmsted County (MN) of patients undergoing surgery for primary hyperparathyroidism. Patients’ demographic data, preoperative and postoperative laboratory values, clinical characteristics, surgical treatment, and follow-up were noted. Results: A total of 345 patients were identified, 75.7% female, and median age 58.4 years [interquartile range (IQR): 17.6]. In all, 68% of patients were asymptomatic and the most common symptoms were musculoskeletal complaints (28.4%) and nephrolithiasis (25.6%). Preoperative median serum calcium was 11 mg/dL (IQR: 10.8–11.4 mg/dL), and median parathyroid hormone was 90 pg/mL (IQR: 61–169 pg/dL). Bilateral cervical exploration was performed in 38% and single gland resection in 79% of cases. Median postoperative serum calcium was 9.2 mg/dL (IQR: 5.5–11.3). Nine percent of patients presented persistence of hypercalcemia, and recurrence was found in 14% of patients. Highest postoperative median serum calcium was 10 mg/dL (IQR: 6–12.4), and median number of postoperative calcium measurements was 10 (IQR: 0–102). Postoperative hypercalcemia was identified in 37% of patient. Fifty-three percent were attributed to secondary causes, most commonly medications, 22%. Three percent of patients required treatment for postoperative hypercalcemia. Median time to recurrence and death were 12.2 and 16.7 years, respectively. Conclusion: Recurrent hypercalcemia after successful parathyroidectomy is higher than previously reported. Most cases are transient and often associated to other factors with only the minority requiring treatment. Long-term follow-up of serum calcium should be considered in patients after successful parathyroidectomy.

Background: Uric acid (UA) concentration within carotid plaque and its association with cerebrovascular events have not been detected or quantified. Systemically, serum UA is a marker of inflammation and risk factor for atherosclerosis. However, its association with carotid plaque instability and stroke pathogenesis remains unclear. In patients undergoing carotid endarterectomy, we aimed to determine whether UA is present differentially in symptomatic versus asymptomatic carotid plaques and whether serum UA is associated with cerebrovascular symptoms (stroke, transient ischemic attack, or amaurosis fugax). Methods: Carotid atherosclerotic plaques were collected during carotid endarterectomy. The presence of UA was assessed using Gomori methenamine silver staining as well as anti-UA immunohistochemical staining and its quantity measured using an enzymatic colorimetric assay. Clinical information was obtained through a retrospective review of data. Results: UA was more commonly detected in symptomatic (n=23) compared with asymptomatic (n=9) carotid plaques by Gomori methenamine silver (20 [86.9%] versus 2 [22.2%]; P =0.001) and anti-UA immunohistochemistry (16 [69.5%] versus 1 [11.1%]; P =0.004). UA concentration was higher in symptomatic rather than asymptomatic plaques (25.1 [9.5] versus 17.9 [3.8] µg/g; P =0.021). Before carotid endarterectomy, serum UA levels were higher in symptomatic (n=341) compared with asymptomatic (n=146) patients (5.9 [interquartile range, 4.6–6.9] mg/dL versus 5.2 [interquartile range, 4.6–6.2] mg/dL; P =0.009). Conclusions: The current study supports a potential role of UA as a potential tissue participant and a systemic biomarker in the pathogenesis of carotid atherosclerosis. UA may provide a mechanistic explanation for plaque instability and subsequent ischemic cerebrovascular events.

Full-length parathyroid hormone (PTH 1–84) is crucial for the regulation of calcium and phosphate homeostasis and bone remodeling. PTH 1–84 is metabolized into various PTH fragments, which are measured with varying levels of efficiency by PTH immunoassays. These PTH fragments, which increase in serum as CKD progresses, could potentially modulate the effects of PTH 1–84 and contribute to CKD-associated bone disorders. To obtain a true biologic representation of total PTH bioactivity, it is necessary to measure not only PTH 1–84 but also PTH fragments that are present in circulation. Traditional second-generation PTH immunoassays collectively measure PTH 1–84, PTH fragments, and post-translationally modified PTH 1–84, making it difficult to accurately predict the character of underlying renal osteodystrophy. This review highlights current advances in methods available for PTH measurement and the clinical relevance of PTH fragments in CKD. We emphasize the usefulness of mass spectrometry as a potential reference method for PTH measurement.