Faculty Bibliography

In May 2023 the World Health Organization (WHO) declared the end of COVID-19 as a public health emergency. Seroprevalence studies performed in African countries, such as Cameroon, depicted a much higher COVID-19 burden than reported by the WHO. To better understand humoral responses kinetics following infection, we enrolled 333 participants from Yaoundé, Cameroon between March 2020 and January 2022. We measured the levels of antibodies targeting the SARS-CoV-2 receptor-binding-domain (RBD) and the Spike glycoproteins of Delta, Omicron BA.1 and BA.4/5 and the common cold coronavirus HCoV-OC43. We also evaluated plasma capacity to neutralize authentic SARS-CoV-2 virus and to mediate Antibody-Dependent Cellular Cytotoxicity (ADCC). Most individuals mounted a strong antibody response against SARS-CoV-2 Spike. Plasma neutralization waned faster than anti-Spike binding and ADCC. We observed differences in humoral responses by age and circulating variants. Altogether, we show a global overview of antibody dynamics and functionality against SARS-CoV-2 in Cameroon.

Mutations that accumulate in the human male germline with age are a major driver of genetic diversity and contribute to genetic diseases. However, aging-related male germline mutation rates have not been measured directly in germline cells (sperm) at the level of individuals. We developed a study design in which we recalled 23 sperm donors with prior banked samples to provide new sperm samples. The old and new sequential sperm samples were separated by long timespans, ranging from 10 to 33 years. We profiled these samples by high-fidelity duplex sequencing and demonstrate that direct high-fidelity sequencing of sperm yields cohort-wide mutation rates and patterns consistent with prior family-based (trio) studies. In every individual, we detected an increase in sperm mutation burden between the two sequential samples, yielding individual-specific measurements of germline mutation rate. Deep whole-genome sequencing of sequential sperm samples from two individuals followed by targeted validation measured remarkably stable mosaicism of clonal mutations that likely arose during embryonic and germline development, suggesting that age did not substantially impact the diversity of spermatogonial stem cell pools in these individuals. Our application of high-fidelity and deep whole-genome sequencing to sequential sperm samples provides insight into aging-related mutation processes in the male germline.

BACKGROUND:Most donor hearts offered for heart transplant (HT) in the United States (US) are turned down. We aimed to understand the reasons for this - focusing on those related to the potential recipient and HT center (i.e. donor-unrelated reasons for refusal). METHODS:The Donor Heart Study (DHS) enrolled 4,333 adult potential heart donors in US from 2015 - 2020. Separately by donor, each HT center who refused an offer for that donor was surveyed on their reason(s) for refusal. We measured the prevalences of 18 distinct donor-unrelated reasons for refusal and their association with the timing of offers (weekend vs. weekday). RESULTS:Our analytic sample included 14,132 unique surveys, each representing a declined offer for one of 3083 donors (mean per donor: 2.56; range: 1 - 17). Donor-unrelated reasons were cited in 24.3% (n = 3441) of surveys; among these, recipient issues (i.e. "recipient ill) were most common (cited in 7%) while resource-related issues (e.g. "logistics", "surgeon unavailable") were rare (<1%). Neither showed a significant time trend; however, other reasons ("already considering another offer", "distance too far") did so, with an abrupt uptick after 2018. We found that several donor-related (but no donor-unrelated) reasons for refusal (e.g. left ventricular hypertrophy, social risk behaviors) were significantly more common on weekends. Their "weekend-predominance" was not explained by differences in objective donor characteristics. CONCLUSIONS:Nearly one quarter of donor heart offer refusals are due to donor-unrelated reasons. Weekend-predominant reasons for offer refusal signal the highly subjective nature of donor assessment and warrant further scrutiny.

OBJECTIVES/OBJECTIVE:To evaluate the yield of CT-guided biopsy of 18F-piflufolastat PET avid osseous lesions in suspected prostate metastases. METHODS:Retrospective review of computed tomography guided biopsies targeting 18F-piflufolastat avid lesions on PET/CT or PET/MR performed between 2022 and 2024. Demographics, image modality, biopsy system, number of cores, lesion location, lean body mass corrected SUV (SUL) and pathology were recorded. Biopsied lesions were compared to the PROMISE (prostate cancer molecular imaging standardized evaluation) scoring system, version 2. RESULTS:Eighteen patients were included, average age 68.7 years. Lesions were defined as: ≥ 50 % sclerotic (n = 10), <50 % sclerotic (n = 7), occult (n = 0), and lytic (n = 1). A technically successful pathologic diagnosis was made in 94 % of biopsies (n = 17). Histopathological diagnosis included: metastatic prostate adenocarcinoma (n = 12), benign with fibrotic/densely sclerotic bone or normocellular bone marrow (n = 5), and metastatic non-small cell lung carcinoma (n = 1). The median SUL on PET for all patients was 7.9 (IQR 13.3), 2.6 (0.3) for benign biopsies, and 8.8 (12.5) for malignant biopsies. Major identifiable differences between biopsies yielding a metastatic versus benign diagnosis included: higher SUL (p-value = 0.03), target lesion volume (p-value = 0.01), and higher incidence of sclerotic lesions (p value = 0.003); however, multivariate analysis did not find these to be statistically significant predictors (p-value >0.05). The prostate cancer lesion biopsy positive group had significantly higher PROMISE scores than the negative group (p = 0.03). CONCLUSION/CONCLUSIONS:CT-guided biopsy of bone lesions demonstrating avidity for 18F-piflufolastat can be performed with a high diagnostic yield.

Gliomas are the most common primary brain tumors and a major source of mortality and morbidity in adults and children. Recent genomic studies have identified multiple molecular subtypes; however metabolic characterization of these tumors has thus far been limited. We performed metabolic profiling of 114 adult and pediatric primary gliomas and integrated metabolomic data with transcriptomics and DNA methylation classes. We identified that pediatric tumors have higher levels of glucose and reduced lactate compared to adult tumors regardless of underlying genetics or grade, suggesting differences in availability of glucose and/or utilization of glucose for downstream pathways. Differences in glucose utilization in pediatric gliomas may be facilitated through overexpression of SLC2A4, which encodes the insulin-stimulated glucose transporter GLUT4. Transcriptomic comparison of adult and pediatric tumors suggests that adult tumors may have limited access to glucose and experience more hypoxia, which is supported by enrichment of lactate, 2-hydroxyglutarate (2-HG), even in isocitrate dehydrogenase (IDH) wild-type tumors, and 3-hydroxybutyrate, a ketone body that is produced by oxidation of fatty acids and ketogenic amino acids during periods of glucose scarcity. Our data support adult tumors relying more on fatty acid oxidation, as they have an abundance of acyl carnitines compared to pediatric tumors and have significant enrichment of transcripts needed for oxidative phosphorylation. Our findings suggest striking differences exist in the metabolism of pediatric and adult gliomas, which can provide new insight into metabolic vulnerabilities for therapy.

BACKGROUND:As more transgender adolescents and young adults seek gender-affirming care, questions persist about how their desire for potentially fertility-affecting treatment intersects with their fertility intentions. METHODS:We surveyed 125 individuals born with a uterus and ovaries, living in the United States, initially prescribed gender-affirming testosterone at or before age 18, about their interest in genetically related children and history of fertility preservation and fertility-affecting procedures. RESULTS:Twenty-two percent of respondents did not want children, and 47% wanted children but did not think a genetic relationship was important. Another 8% indicated having genetically related children was important and 17% indicated they did not know. Only 47% recalled counseling about fertility preservation. Those who might want genetically related children were less satisfied when they did not recall counseling (p = .001). Significantly more people in the group who might want genetically related children still had one or both ovaries (100% vs. 86%; p = .03), desired to carry a pregnancy in the future or were unsure (30% vs. 8%; p = .01), and either desired to use their eggs for genetically related children or were unsure (93% vs. 26%; p < .001). CONCLUSIONS:More than one-half of individuals prescribed gender-affirming testosterone as adolescents had no interest in genetically related children. Those who were interested in genetically related children were more likely to have other fertility-preserving interests and behaviors, including potentially desiring a pregnancy and still having one or both ovaries. This finding suggests that fertility-related behaviors of individuals prescribed gender-affirming testosterone are in line with their stated goals.

Individuals with heritable thoracic aortic disease (HTAD) face a high risk of deadly aortic dissections, but genetic testing identifies causative variants in only a minority of cases. We explored the contribution of non-canonical splice variants (NCVAS) to thoracic aortic disease (TAD) using SpliceAI and sequencing data from diverse cohorts, including 551 early-onset sporadic dissection cases and 437 HTAD probands with exome sequencing, 57 HTAD pedigrees with whole genome sequencing, and select sporadic cases with clinical panel testing. NCVAS were identified in syndromic HTAD genes such as FBN1, SMAD3, and COL3A1, including intronic variants in FBN1 in two Marfan syndrome (MFS) families. Validation in the Penn Medicine BioBank and UK Biobank showed enrichment of NCVAS in HTAD-associated genes among dissections. These findings suggest NCVAS are an underrecognized contributor to TAD, particularly in sporadic dissection and unsolved MFS cases, highlighting the potential of advanced splice prediction tools in genetic diagnostics.

High-dimensional multiplexed imaging can reveal the spatial organization of tumour tissues at the molecular level. However, owing to the scale and information complexity of the imaging data, it is challenging to discover and thoroughly characterize the heterogeneity of tumour microenvironments. Here we show that self-supervised representation learning on data from imaging mass cytometry can be leveraged to distinguish morphological differences in tumour microenvironments and to precisely characterize distinct microenvironment signatures. We used self-supervised masked image modelling to train a vision transformer that directly takes high-dimensional multiplexed mass-cytometry images. In contrast with traditional spatial analyses relying on cellular segmentation, the vision transformer is segmentation-free, uses pixel-level information, and retains information on the local morphology and biomarker distribution. By applying the vision transformer to a lung-tumour dataset, we identified and validated a monocytic signature that is associated with poor prognosis.

BACKGROUND:Hepatic artery infusion with floxuridine is a treatment option for patients with colorectal liver metastases or intrahepatic cholangiocarcinoma. Outcomes from newer centers are understudied. Predictive markers are needed, and quantitative circulating tumor DNA is an emerging candidate method for predicting response in patients receiving hepatic artery infusion. We aimed to describe safety, feasibility, early oncologic outcomes, and quantitative circulating tumor DNA dynamics in patients treated with hepatic artery infusion at a newly established program. METHODS:Single-institution analysis of patients who underwent hepatic artery infusion pump placement (April 2022-April 2024) was conducted. Primary outcomes included safety and feasibility (receiving ≥1 cycle of floxuridine). Secondary outcomes included radiographic response (Response Evaluation Criteria in Solid Tumors 1.1), relative dose intensity of floxuridine received, and quantitative circulating tumor DNA response. RESULTS:A total of 36 patients underwent hepatic artery infusion pump placement (colorectal liver metastases: 32; cholangiocarcinoma: 4). Technical success was 100%. Feasibility was 97%. One patient experienced mortality at 90 days from disease progression. Three patients (8%) experienced a total of 5 hepatic artery infusion pump-specific complications (pump pocket [n = 3], hemorrhage [n = 1], biliary sclerosis [n = 1]). Median relative dose intensity was 68.5% (colorectal liver metastases: 68.3%; cholangiocarcinoma 72.5.0%). For the 27 patients who underwent floxuridine therapy with available postoperative imaging, disease control rate was 97% (partial response: n = 15; stable disease: n = 11). Quantitative circulating tumor DNA was obtained from 16 patients (44%). Circulating tumor DNA dynamics appeared to correlate with and precede radiographic response. CONCLUSIONS:Implementation of a new hepatic artery infusion program is safe and feasible with promising early oncologic outcomes. Circulating tumor DNA tracking is achievable and dynamic changes in circulating tumor DNA may correlate with radiographic response to treatment.