The HSP90-MYC-CDK9 network drives therapeutic resistance in mantle cell lymphoma

Brexucabtagene autoleucel CAR-T therapy is highly efficacious in overcoming resistance to Bruton's tyrosine kinase inhibitors (BTKi) in mantle cell lymphoma. However, many patients relapse post CAR-T therapy with dismal outcomes. To dissect the underlying mechanisms of sequential resistance to BTKi and CAR-T therapy, we performed single-cell RNA sequencing analysis for 66 samples from 25 patients treated with BTKi and/or CAR-T therapy and conducted in-depth bioinformatics™ analysis. Our analysis revealed that MYC activity progressively increased with sequential resistance. HSP90AB1 (Heat shock protein 90 alpha family class B member 1), a MYC target, was identified as early driver of CAR-T resistance. CDK9 (Cyclin-dependent kinase 9), another MYC target, was significantly upregulated in Dual-R samples. Both HSP90AB1 and CDK9 expression were correlated with MYC activity levels. Pharmaceutical co-targeting of HSP90 and CDK9 synergistically diminished MYC activity, leading to potent anti-MCL activity. Collectively, our study revealed that HSP90-MYC-CDK9 network is the primary driving force of therapeutic resistance.

P-557 Fresh Transfer with Supernumerary PGT-A Biopsy: The Best of Both Worlds

Study question

What is difference in time to pregnancy for patients between 35-40 years who undergo fresh versus frozen-thawed embryo transfers with or without PGT-A?

Summary answer

Patients undergoing fresh embryo transfer (ET) had a shorter time to pregnancy within the same cycle compared to patients electing for freeze-all cycles.

What is known already

When comparing clinical pregnancy rates following fresh versus frozen-thawed embryo transfers, multiple studies have shown a higher clinical pregnancy rate among frozen-thawed embryo transfers compared to fresh embryo transfers. Particularly for patients over 35 years, there has been a growing national trend towards elective freeze-all cycles, for reasons such as to pursue preimplantation genetic testing for aneuploidy (PGT-A). While PGT-A testing can be effective in reducing miscarriage in patients age 38-40, there is limited studies evaluating time to pregnancy within this population, especially in the context of each passing month’s effect on fertility.

Study design, size, duration

Retrospective review was performed for 697 IVF cycles and 881 transfers from January 2016 – December 2021 at a single academic fertility center in Boston, Massachusetts. Two-tailed t-tests and analysis of variance (ANOVA) were used to compare differences, with p-value less than 0.05 set for statistical significance. All PGT-A testing as performed using a modified FAST-SeqS next generation sequencing method (Invitae, San Francisco, CA).

Participants/materials, setting, methods

Cycle characteristic of patients between 35-40 were categorized to four groups: Fresh ET with PGT-A of supernumerary embryos (82 transfers), Fresh ET without PGT-A (526 transfers), Freeze-all cycle with PGT-A (223 transfers), and Freeze-all cycle without PGT-A (50 transfers). All averages were calculated within one IVF cycle with a single cohort of embryos. Time to pregnancy was calculated in days from day of retrieval to positive serum beta-human chorionic gonadotropin (bHCG).

Main results and the role of chance

Among the 881 transfers, 478 had fresh ETs and 403 had frozen-thawed ETs with or without PGT-A respectively. When comparing fresh and freeze-all cycles, there was no difference in average numbers of transfers performed to achieve a clinical pregnancy (1.27 fresh vs 1.25 freeze-all, p = 0.56). For patients who didn’t elect for PGT-A, there was no difference in number of embryos transferred (1.86 for fresh versus 2.06 for freeze-all, p = 0.54). For patients who elected for PGT-A, the average number of embryos transferred was higher for patients that opted for fresh transfer over freeze-all (1.67 for fresh ET with PGT-A of supernumerary embryos versus 1.24 for freeze-all PGT-A, p = 0.0025). Average days from oocyte retrieval to pregnancy was significantly lower for all fresh ETs (28.8 days for fresh ET without biopsy, 26.6 days for fresh ET with biopsy of supernumerary embryos, p < 0.0001) compared to all freeze-all transfers (110.9 days for freeze-all ET without biopsy, 119.5 days for freeze-all ET with biopsy, p < 0.0001). This delay in time to pregnancy is partially attributed to pending genetic testing results, however, these results usually return in 2-3 weeks, which does not account for the near 3-month delay in time to pregnancy among freeze-all cycles.

Limitations, reasons for caution

These retrospective findings were of all women who achieved pregnancy from one retrieval. These results are not reflective of the patients who needed to undergo multiple cycles to achieve pregnancy, or patients who never achieved pregnancy.

Wider implications of the findings

These findings suggest that PGT-A may be offered to patients > 35 to minimize the number of embryos for transfer. Patients opting for a fresh transfer of an untested embryo and biopsy of supernumerary embryos had a nearly 3-month shorter time to pregnancy than those electing for a freeze-all cycle

Trial registration number

not applicable

O-184 The impact of cryopreserved sperm on Intrauterine Insemination (IUI) outcomes: Is frozen as good as fresh?

Study question

Are the outcomes of IUI cycles [with or without ovarian stimulation (OS)] comparable when frozen instead of fresh-ejaculated sperm is utilized?

Summary answer

Overall, clinical outcomes did not differ significantly between frozen and fresh sperm IUI cycles, although specific subgroups might benefit from fresh sperm utilization.

What is known already

At present, data from animal studies point towards less favorable outcomes with frozen sperm utilization, implicating cryopreservation-induced damages to the cytoskeleton, DNA, and acrosome leading to adverse effects on spermatozoa’s motility, viability, and ability to fuse with the oocyte. Assisted Reproductive Technology (ART) data, mostly focusing on severe male factor infertility diagnoses, suggest no major differences between in-vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) cycles utilizing frozen over fresh sperm, often surgically extracted. Nevertheless, contemporary data from IUI(±OS) cycles are still scarce.

Study design, size, duration

Data from 5335 IUI(±OS) cycles (time-period: 01/2004-12/2021) from a large academic fertility center were retrospectively reviewed. Cycles were stratified in two groups based on utilization of frozen instead of fresh-ejaculated sperm for the IUI [FROZEN (n = 1871, all infertility diagnoses), and FRESH (n = 3464, idiopathic infertility diagnosis only), respectively]. Cycle outcomes were compared between groups.

Participants/materials, setting, methods

Participants: women seeking IUI (±OS) treatments.

Outcome Measures: HCG-positivity, clinical pregnancy (CP), spontaneous abortion (SAB) rates. Initial analysis included all cycles irrespective of OS regimen.  Cycles were then stratified by OS regimen into three subgroups [injectable gonadotropins, oral medications (OM): clomiphene-citrate and letrozole, and unstimulated/natural]. Odds ratios (OR) for all relevant outcomes were calculated utilizing logistic regression and adjusted for maternal age, day-3 FSH, and OS regimen. Time-to-pregnancy and first-cycle only analyses were also performed.

Main results and the role of chance

Unadjusted HCG-positivity, and CP were lower in the FROZEN compared to the FRESH group (12.2% vs. 15.6%, p < 0.001; 9.4% vs. 13.0%, p<.001, respectively), which persisted only among OM after stratification (9.9% vs. 14.2% HCG-positivity, p=.030; 8.1% vs. 11.8% CPR, p=.041, for FROZEN compared to FRESH, respectively).

Among all cycles, adjOR(95%CI) for HCG-positivity and CP were respectively: 0.75(0.56-1.02), and 0.77(0.57-1.03), ref: FRESH). Following stratification by OS regimen, adjOR(95%CI) for HCG-positivity and CP showed no difference between groups among gonadotropin and natural cycles but favored the FRESH group in OM cycles [HCG-positivity: 0.55(0.30-0.99); CP: 0.49(0.25-0.95), ref.: FRESH]. SAB odds did not differ between groups among OM and natural cycles but were lower in the FROZEN compared to FRESH group among gonadotropin cycles [adjOR(95%CI): 0.13(0.02-0.98), ref.: FRESH]. However, regarding the latter comparison, numbers were small and the 95%CI wide.  When analysis was limited to first-cycles only and further stratified by OS regimen, the previously noted differences in CP and SAB odds no longer existed within the OS subgroups.

Nevetheless, time-to-conception was slightly longer in the FROZEN compared to the FRESH group (3.84 vs. 2.58 cycles, p<.001).

Limitations, reasons for caution

Study is limited by its retrospective nature. The two groups differed somewhat in age, infertility diagnosis, utilized OS regimen, and as expected in total motile sperm counts. Despite the less favorable characteristics of the FROZEN group, no detrimental effect of sperm cryopreservation on IUI outcomes was noted.

Wider implications of the findings

Our study, the largest to date, showed no significant difference in IUI outcomes between cycles utilizing frozen instead of fresh-ejaculated sperm. Although, specific subgroups might benefit from fresh sperm utilization and time-to-pregnancy might be shorter with fresh over frozen sperm, patients should be counselled about the non-inferiority of frozen sperm.

Trial registration number

Not applicable

P-342 The impact of Clomiphene Citrate (CC) on the endometrium in comparison to gonadotropins (Gn) in intrauterine-insemination treatments (IUI): Is it thinner and does it matter?

Study question

Utilizing patients as their own controls, does endometrial thickness (EMT) differ between CC/IUI and Gn/IUI? Does EMT differ between CC-cycles with and without associated conception?

Summary answer

Within-patient, CC resulted in thinner EMT compared to Gn. CC-cycles associated with conception compared to the ones without it, had thicker endometria.

What is known already

CC, unlike gonadotropins, may have an anti-estrogenic effect on the endometrium. Concerns exist that the thinning of the endometrium might be associated with altered endometrial development and receptivity. However, available data in CC cycles remain inconsistent, probably due to patient and protocol heterogeneity. Currently, it remains unclear whether CC treatments produce a thinner endometrium, compared to gonadotropins, in the same patient. Furthermore, it is uncertain whether such a difference, if one exists, has a consequential effect on IUI cycle outcomes.

Study design, size, duration

Design: retrospective.

Duration: 1/2004-9/2021

Cohort 1 utilized women as their own controls to evaluate CC’s impact on the endometrium and included all cycles from women who sought fertility treatments and initially underwent CC/IUI (CC1, n = 1252) followed by Gn/IUI (Gn1, n = 1307).

Cohort 2 included all cycles from women seeking fertility treatments at the same center that conceived following CC/IUI treatments (CC2, n = 686).

EMT was compared between groups (CC1 vs. Gn1, CC1 vs. CC2).

Participants/materials, setting, methods

Outcome measures:

Primary: EMT (mm).

Secondary: HCG-positivity (pos-HCGR), clinical pregnancy (CPR), and spontaneous abortion rates (SABR).

Statistics:

Regression analysis was used to calculate Odds Ratios (OR) with associated 95% confidence intervals (95%CI), adjusting for potential confounders [maternal age, Body Mass Index (BMI), prior parity, day of EMT measurement relative to trigger). Generalized estimating equations (GEE) model were utilized to account for multiple cycles per patient. P < 0.05 was considered significant.

Main results and the role of chance

In cohort 1, despite CC1 exhibiting non-inferior ovarian response compared to Gn1 (as assessed by preovulatory follicular number), EMT was significantly thinner in CC1 compared to Gn1 [Median(IQR): 7.0(5.7-8.3) vs. 8.9(7.4-10.0), p<.001]. When CC1 was compared to CC2 (CC conceiving), EMT was also thinner [Median(IQR): 7.0(5.7-8.3) vs. 7.5(6.2-9.0), for CC1 vs. CC2, respectively, p<.001]. A higher percentage of CC1 compared to Gn1 cycles resulted in EMT≤7mm (48.9% vs. 16.7% , for CC1 vs. Gn, respectively; p<.001). Most subsequent Gn cycles (82.8%), in the same women, resulted in thicker EMT compared to CC1. AdjOR, in generalized linear mixed models, suggested that CC2 when compared to CC1 cycles had thicker EMT [adjOR(95%CI): 1.81, (1.41,2.35), p<.001].

Interestingly, clinical pregnancies were observed even when EMT was ≤4mm in both CC2 and Gn1 groups and SABR did not differ between cycles with EMT≤4mm and the ones with thicker EMT (2.5% vs. 11.5%, p=.258, in CC2; 0% and 12.3%, p=.544, in Gn1; SABR EMT ≤4 vs. 4 mm, respectively). GEE models suggested an association between EMT and CPR in CC cycles (CC1&CC2), [adjOR(95%CI): 1.12(1.07,1.18), p<.001)] while in Gn1, no such association was observed.

Limitations, reasons for caution

Our study was limited by its retrospective design. Reflecting our selection criterion, in cohort 1, most CC cycles did not result in pregnancy, restricting relevant comparisons. Number of cycles resulting in EMT ≤7mm, and particularly ≤4mm, was limited, and consequently respective results should be interpreted cautiously.

Wider implications of the findings

Utilizing patients as their own controls, we showed that CC compared to gonadotropins resulted in thinner endometrium. Given comparable follicular response, and potentially estradiol levels, thinner endometrium might have resulted from CC’s anti-estrogenic effect. Furthermore, patients conceiving on CC had a thicker endometrium compared to the ones that did not.

Trial registration number

NA

P-434 Is there an association between pre-ovulatory estradiol levels and placental pathology of singleton livebirths conceived with gonadotropins/intrauterine insemination (Gn/IUI) treatments?

Study question

Is pre-ovulatory estradiol level associated with placental weight (PW) and abnormality rates (PAR) in singleton livebirths resulting from gonadotropins/intrauterine insemination (Gn/IUI) treatments?

Summary answer

In Gn/IUI-conceived, singleton-livebirths with available placental pathology, an association was noted between preovulatory estradiol levels and PW, but not between estradiol and PAR.

What is known already

Data suggest an association between ART and placental-mediated pregnancy complications, as well as increased rates of placental pathology. Supraphysiologic levels of preovulatory estradiol have been implicated in abnormal placentation. Whether such an effect is noted in Gn/IUI treatments, where levels of estradiol are lower, nevertheless supraphysiologic, remains unknown.

Study design, size, duration

We retrospectively reviewed data from 560 Gn/IUI-conceived, singleton-livebirths (1/2004-1/2021) recruited from a large academic fertility center. Placental pathology information was available from 218 cycles. These cycles were stratified by pre-ovulatory estradiol levels in quartiles [Q1(lower)-Q4 (higher)]. PW [grams & percentiles (%iles)], and rates of placental abnormalities (classified as anatomic, inflammatory, infectious, and vascular/thrombotic) were compared between groups.

Participants/materials, setting, methods

Participants: Women with Gn/IUI-conceived, singleton-livebirths with available placental pathology.

Outcome Measures: PW and PAR.

Statistics: Regression analysis was utilized to estimate the association of pre-ovulatory estradiol %iles with PW and PAR, adjusting for potential confounders (PW: maternal and gestational age, BMI, infertility diagnosis, medical complications, infant gender; PAR: maternal and gestational age, BMI, race). Adjusted Odds Ratios (OR) with 95%CI were calculated for the latter.

Main results and the role of chance

Mean PW(±SD) in grams were 477.3(±124.1), 445.9(±107.4), 451.2(±113.9), and 438.9(±107.0) in Q1 through Q4 (p=.368). Small placentas (≤10thPW %ile) accounted for more than a third of the total in all estradiol quartiles (37.5%, 49.2%, 37.5%, and 42.2%, p=.539, Q1-Q4, respectively). Similarly, increasingly higher percentages of placentas ≤25th PW %ile were noted with increasing estradiol quartiles (47.9%, 57.6%, 62.5% and 64.5%, in Q1-Q4 respectively, p=.347). After adjusting for potential confounders, we noted a mean 13.7 grams decrease in PW between each subsequent estradiol quartile [ adjβ-coeff (95%CI): -13.7(-27.7-0.3), p=.055]. When estradiol levels were analyzed as a continuous variable, an inverse association with PW [ adjβ-coeff (95%CI): -0.08 (-0.16-(-0.01)), p=.026] was noted. Adjusted ORs for small placenta did not differ between estradiol quartiles or when estradiol was analyzed as a continuous variable [adjORs(95%CI): 1.73(0.74-4.07), 1.10(0.47-2.55), 1.81(0.69-4.72), for Q2-Q4, Q1 as ref.; 1.001(1.000-1.003), p=.167; respectively].

There was no significant association between placental abnormality rates (PAR) and estradiol, either before or after adjustment [adjORs(95%CI): i) Anatomic : 1.16(0.49-2.74), 1.52(0.65-3.59), and 1.17(0.45-3.02); ii) Inflammatory : 0.40(0.13-1.25), 0.79(0.28-2.17), and 1.25(0.42-3.73); iii) Infectious : 0.89(0.35-2.25), 1.67(0.68-4.13), and 0.58(0.20-1.67); iv) Vascular/thrombotic : 0.88(0.37-2.08), 1.87(0.80-4.41), and 0.95(0.36-2.49); for Q2-Q4 vs. Q1].

Limitations, reasons for caution

There are several limitations, including the retrospective design, possible selection bias resulting from the decision to obtain placental pathology. Nonetheless, birth weights did not differ between those with and without placental pathology. Estradiol levels, albeit supraphysiologic, are much lower than those in ART and differences might be masked.

Wider implications of the findings

In Gn/IUI-conceived, singleton-livebirths with available placental pathology, an association was noted between preovulatory estradiol levels and placental weight, but not between estradiol and the rate of specific placental abnormalities (PAR). Since estradiol levels are lower than those observed in ART, an association might have been missed.

Trial registration number

not applicable

P-294 Use of Artificial Intelligence to Assess the Effects of Assisted Hatching on Embryo Development and Implantation Potential

Study question

Does the use of laser-assisted hatching (AH) on cleavage stage embryos affect in vitro preimplantation embryo development or implantation potential?

Summary answer

There is no difference in blastocyst conversion rate or implantation potential of embryos following AH at the cleavage stage for patients under age 35 years.

What is known already

Laser-AH is the process of creating an opening within the zona pellucida on cleavage stage embryos to facilitate biopsy of trophectoderm cells for preimplantation genetic testing (PGT). Studies have shown that PGT for aneuploidy (PGT-A) in patients under 35 years have reduced pregnancy rates compared to those not undergoing biopsy. This is attributed to the additional micromanipulation events involved with PGT-A may decrease the viability of embryos and compromise their implantation potential. We aimed to objectively compare the impact of AH on embryo development using an artificial intelligence (AI)-algorithm trained to assess embryo quality and predict developmental fate.

Study design, size, duration

A retrospective dataset from patients under 35 years was generated from two timepoints: cleavage stage embryos immediately before AH between 60-64 hours post insemination (hpi); and blastocyst stage embryos between 110-115 hpi prior to transfer or vitrification. Time-lapse imaging was obtained using the EmbryoScope (Vitrolife). Cleavage stage embryo images were used to train a convolutional neural networks (CNN) to predict and classify the development and implantation potential of cleavage and blastocyst stage embryos.

Participants/materials, setting, methods

Time-lapse images were collected for 1444 cleavage stage embryos spanning 189 in vitro fertilization (IVF) cycles between January 2014 – December 2021 at a single academic fertility center in Boston. Embryos were categorized into two groups: Day 3 embryos with AH (D3+AH) and without AH (D3-No AH). Each patient had a single blastocyst embryo transfer with a known outcome. Two-tailed t-tests were used to compare differences, with p-value less than 0.05 set for statistical significance.

Main results and the role of chance

The dataset included 1035 embryos with AH (D3+AH) and 409 embryos without AH (D3-No AH). There were no differences in AI-predicted blastocyst development between Day 3 embryos with AH and without AH (64.1% vs 64.1%) or AI-predicted high quality blastocyst development rate between these two groups (43.8% vs 40.8%), respectively. On Day 5 there were no differences in the AI-categorization of embryos at the blastocyst stage between embryos with or without AH (62.3% vs 62.5%) or AI-categorization of high-quality blastocyst development (45.2% vs 41.8%), respectively. AI predicted a similar implantation potential between embryos with and without AH at the cleavage stage (61.1% vs 69.9%). When stratifying to only the embryos transferred, there were no differences in the AI-predicted blastocyst development between Day 3 embryos with AH and without AH (96.0% vs 97.1%) or in the AI-predicted high quality blastocyst development rate between these two groups (72.0% vs 82.7%). AI predicted a similar implantation potential between embryos with and without AH at the cleavage stage (72.0% vs 69.0%). These results correspond with the true clinical pregnancy rate between the AH and Non-AH groups (68.0% vs 61.9%, p = 0.44).

Limitations, reasons for caution

These retrospective findings were of patients who had time-lapse imaging of cleavage stage and blastocysts available. Additionally, we focused on high prognosis patients that were eligible for single blastocyst stage embryo transfer. Clinical pregnancy rate was examined, not spontaneous abortion or live birth rates.

Wider implications of the findings

Utilization of AI technology allows for more objective and standardized methods for examining the impact of laboratory procedures on the developmental fate of embryos. This study demonstrated the safety of utilizing laser-assisted hatching on embryo development within this study population.

Trial registration number

None

P-426 Placental pathology following Intrauterine Insemination (IUI) with or without Ovarian Stimulation (OS)

Study question

Do placental weight percentiles (PW %iles) and abnormality rates (PAR) differ in singleton-livebirths following IUI with or without OS [oral medications (OM), and injectable gonadotropins]?

Summary answer

Following singleton-livebirths, PW did not differ between groups, albeit over half of placentas were ≤25th%ile. Placental anatomic abnormalities were more often seen in OM cycles.

What is known already

ART data suggest a possible association between stimulation-induced supraphysiologic estradiol levels and increased risk of placental abnormalities, as well as subsequent placental-mediated pregnancy complications, such as preeclampsia. Whether there is an association between OS protocols for IUI and placental pathology remains unknown.

Study design, size, duration

Data from 975 IUI(±OS) cycles resulting in singleton livebirths at a large academic fertility center between 01/2004 and 01/2021, were retrospectively reviewed. In 386 cycles a full placental pathologic examination was available. Placentas were stratified by OS regimen into three groups: gonadotropins (n = 222), OM [Clomiphene Citrate (CC)/Letrozole (LTZ); n = 129], and unstimulated / natural (n = 35). PW and PAR were compared between groups.

Participants/materials, setting, methods

Participants: Women delivering a singleton liveborn following IUI(±OS) treatments with placental pathology available.

Outcome Measures: PW (grs & %iles), and PAR (classified as anatomic, inflammatory, infectious, and vascular/thrombotic).

Statistics: Regression analysis was utilized to compare PW and PAR between groups, adjusting for potential confounders (PW: maternal and gestational age, BMI, infertility diagnosis, medical complications, infant gender; PAR: maternal and gestational age, BMI, race). Adjusted Odds Ratios (adjOR, 95%CI) were calculated for the latter.

Main results and the role of chance

Mean(±STDEV) PW (grs) were 451.7(±113.3), 449.2(±102.4), and 481.8(±99.8), for the gonadotropins, OM, and natural groups, respectively. Interestingly, over half of the placentas in all three groups were ≤25th %ile (58.6%, 56.1%, and 52.9%, for gonadotropins, OM, and natural, respectively, p=.249), while 41.8%, 46.4%, and 38.2% were below the 10th %ile (for gonadotropins, OM, and natural, respectively, p=.598). Adjusted PW differences, and adjOR for small placenta (≤10th %ile) did not differ between groups [PW OR(95%CI): 5.6(-17.9-29.2), -28.1(-71.4-15.2), -11.7(-52.6-29.3); small placenta OR(95%CI): 1.04(0.62-1.76); 1.27(0.40-4.01), and 0.96(0.34-2.74) for OM vs. gonadotropins, OM vs. natural, and gonadotropins vs. natural, latter as ref. ].

Regarding PAR, anatomic(43.7%, 52.7%, and 40%, p=.192), inflammatory(20.7%, 27.1%, and 20%, p=.354), infectious(32.9%, 33.3%, and 31.4%, p=.978), and vascular/thrombotic(42.3%, 41.9%, and 42.9%, p=.993) abnormalities rates did not differ between gonadotropins, OM, and natural, respectively. AdjORs(95%CI) for inflammatory, infectious, and vascular/thrombotic abnormalities did not differ significantly between groups. However, anatomic abnormalities were more frequent among OM compared to gonadotropin and natural cycles [adjOR(95%CI): 1.76(1.06-2.91), p=.028, gonadotropins as ref.; 2.52(1.05-6.05), p=.038, natural as ref.].

Limitations, reasons for caution

This study is limited by its retrospective nature. Unfortunately, placental pathology was available only in conceptions clearly identified as resulting from IUI(±OS) treatments. However, birth weights did not differ between those with and without available placental pathology. Natural/IUI cycles were limited in numbers not allowing meaningful conclusions.

Wider implications of the findings

Between IUI-conceived, singleton-livebirths with available placental pathology, mean PW did not differ significantly. However, a higher-than-expected percent of placentas were below the expected %iles, suggesting that IUI(±OS) might be associated with altered placental growth. Placental anatomic abnormalities were more common among OM cycles, compared to gonadotropins, and n atural IUI cycles.

Trial registration number

Not applicable

United States Family Medicine research collaborations associated with higher citation and funding rates

INTRODUCTION Among academic medical disciplines, Family Medicine (FM) research is notable for its breadth of health-care content areas, making it particularly susceptible to interdisciplinary collaboration. AIM This study characterises the degree and typology of such collaborations, and determines whether collaboration patterns are associated with citation frequency and funding. METHODS This cross-sectional study describes collaboration patterns for publications from 2015 indexed in Web of Science and authored by faculty from United States (US) departments of family medicine (DFMs). We determined mean number of total and FM authors per publication, and percentage of publications with FM first or last authors. Publications were categorised by inclusion of non-FM faculty author(s) and number of DFMs represented. RESULTS Overall, 919 FM faculty from 109 DFMs authored a total of 1872 unique publications in 2015. There was an average of 6.8 authors per publication with 1.4 authors being FM faculty. FM faculty were first author on 26.2% and last author on 29.2% of publications. Of all publications, 0.9% were single FM Author; 1.0% were same DFM; 0.3% were multiple DFMs; 72.4% were single FM Author+non-FM; 19.3% were same DFM+non-FM; 6.0% were multiple DFMs+non-FM. FM publications with non-FM faculty authors showed higher citation rates, higher rates of funding, and lower rates of having no funding source. DISCUSSION Most FM publications involved non-FM faculty authors. Collaborations involving non-FM authors were correlated with higher impact publications and projects that were more likely to have been funded.

Supporting Family Medicine Research Capacity: The Critical Role and Current Contributions of US Family Medicine Organizations

BACKGROUND AND OBJECTIVES

Family medicine is continuously advanced by a reinforcing research enterprise. In the United States, each national family medicine organization contributes to the discipline's research foundations. We sought to map the unique and interorganizational roles of the eight US family medicine professional organizations participating in Family Medicine for America's Health (FMAHealth) in supporting family medicine research.

METHODS

We interviewed leaders and reviewed supporting materials from organizations participating in FMAHealth. We explored existing activities, capacity, and collaboration. We identified areas of strength and opportunities for growth and synergy with respect to how the family of family medicine nurtures family medicine research.

RESULTS

The FMAHealth organizations support certain aspects of the family medicine research infrastructure. Six domains were identified through this work: showcasing scholarship, communication and dissemination, workforce development, data-driven initiatives, performing primary research, and advocacy for family medicine research. Each organization's areas of emphasis differ, but we found substantial collaboration on initiatives across organizations, possibly attributable to the fact that many members belong to more than one organization.

CONCLUSIONS

Deliberate contributions to each of the six domains identified herein will be important for the future success of family medicine research. Key opportunity areas described here include coordinated and strategic advocacy for increased funding for family medicine research, dedicated investment in training opportunities, protected effort to grow the next generation of family medicine researchers, pilot funding to build a research base for future high-impact research, and infrastructure to facilitate cross-institutional collaboration and data sharing.

Chronic Opioid Prescribing in Primary Care: Factors and Perspectives

BACKGROUND

Primary care clinicians write 45% of all opioid prescriptions in the United States, but little is known about the characteristics of patients who receive them and the clinicians who prescribe opioids in primary care settings. Our study aimed to describe the patient and clinician characteristics and clinicians' perspectives of chronic opioid prescribing in primary care.

METHODS

Using a mixed methods approach, we completed an analysis of 2016 electronic health records from 21 primary care practices to identify patients who had received chronic opioids, which we defined as in receipt of an opioid prescription for at least 3 consecutive months. We compared those receiving chronic opioids with those not in terms of their demographics, prescribing clinician characteristics, and risk factors for opioid-related harms, as identified by the Centers for Disease Control and Prevention Guideline on Opioid Prescribing for Chronic Pain. We then interviewed 16 primary care clinicians about their perspectives on chronic opioid prescribing.

RESULTS

Of 84,029 patients, 1.1% (902/84,929) received chronic opioid prescriptions. Characteristics associated with being prescribed chronic opioids include being female, being of black or African American race, and having risks for opioid-related harms, such as mental health diagnoses, substance use disorder, and concurrent benzodiazepine use. Clinicians report multiple difficulties in weaning patients from chronic opioids, including medical contraindications of nonopioid alternatives and difficulty justifying weaning by stable long-term patients.

CONCLUSION

Although patients prescribed opioids in primary care have higher risks of opioid-related harms, clinicians report multiple barriers in deprescribing chronic opioids. Future studies should examine strategies to mitigate these harms and engage patients in shared decision making about their chronic opioid use.

The Scholarly Output of Faculty in Family Medicine Departments

Background and Objectives: While prior efforts have assessed the scope of family medicine research, the methods have differed, and the efforts have not been routinely repeated. The purpose of this analysis was to quantify publications, journals, citations, and funding of US family medicine faculty and identify factors associated with these outcomes. Methods: We identified faculty in US departments of family medicine through website searches and performed a cross-sectional study. We included 2015 publications in peer-reviewed journals indexed in Web of Science (a database that aggregates a wide range of catalogs). We calculated descriptive statistics assessing the publications, journals, and citations for family medicine faculty. We conducted bivariate analyses by department region, department size, public/private status, faculty title, and faculty degree. Results: We identified 6,738 faculty at 134 departments, with 15% of faculty having any publications. Family medicine faculty published 3,002 times (mean of 2.9 among those with any publications). The mean number of publications was highest for faculty in departments in the West (3.7), in the third quartile for size (3.6), with a professor title (4.0), and with combined MD or DO/PhD degrees (4.3). Faculty published 84% of the time in non-family medicine journals and were cited 13,548 times. Faculty listed federal funding for over half (52%) of the times they published. Conclusions: Publications from family medicine faculty are not concentrated in family medicine journals and are being referenced by others. These figures are larger than prior estimates and should be tracked over time.

Leucine-tRNA initiates at CUG start codons for protein synthesis and presentation by MHC class I

Effective immune surveillance by cytotoxic T cells requires newly synthesized polypeptides for presentation by major histocompatibility complex (MHC) class I molecules. These polypeptides are produced not only from conventional AUG-initiated, but also from cryptic non-AUG-initiated, reading frames by distinct translational mechanisms. Biochemical analysis of ribosomal initiation complexes at CUG versus AUG initiation codons revealed that cells use an elongator leucine-bound transfer RNA (Leu-tRNA) to initiate translation at cryptic CUG start codons. CUG/Leu-tRNA initiation was independent of the canonical initiator tRNA (AUG/Met-tRNA(i)(Met)) pathway but required expression of eukaryotic initiation factor 2A. Thus, a tRNA-based translation initiation mechanism allows non-AUG-initiated protein synthesis and supplies peptides for presentation by MHC class I molecules.

Cryptic tRNAi shapes the pMHC I repertoire (100.5)

MHC class I molecules present peptides on the cell surface for immune surveillance of viruses and cancer. Interestingly, the peptides are encoded not only in conventional AUG-initiated translational reading frames but also in non-AUG initiated cryptic reading frames. Whether the same or distinct translational machinery is used to produce cryptic peptides at non-AUG start codons, such as CUG, is not known. Here, we show that translational initiation of antigenic precursors at cryptic CUG codons is differentially regulated by ribosomal initiation complexes that contain novel initiator tRNAs. This tRNA is distinct from Met-initiator tRNA and enhances initiation at CUG start codons. Thus, a novel tRNA -based mechanism can supply peptides for presentation by MHC I.

Haploinsufficiency for p190B RhoGAP inhibits MMTV-Neu tumor progression

INTRODUCTION

Rho signaling regulates key cellular processes including proliferation, survival, and migration, and it has been implicated in the development of many types of cancer including breast cancer. P190B Rho GTPase activating protein (RhoGAP) functions as a major inhibitor of the Rho GTPases. P190B is required for mammary gland morphogenesis, and overexpression of p190B in the mammary gland induces hyperplastic lesions. Hence, we hypothesized that p190B may play a pivotal role in mammary tumorigenesis.

METHODS

To investigate the effects of loss of p190B function on mammary tumor progression, p190B heterozygous mice were crossed with an MMTV-Neu breast cancer model. Effects of p190B deficiency on tumor latency, multiplicity, growth, preneoplastic progression and metastasis were evaluated. To investigate potential differences in tumor angiogenesis between the two groups, immunohistochemistry to detect von Willebrand factor was performed and quantified. To examine gene expression of potential mediators of the angiogenic switch, an angiogenesis PCR array was utilized and results were confirmed using immunohistochemistry. Finally, reciprocal transplantation of tumor fragments was performed to determine the impact of stromal deficiency of p190B on tumor angiogenesis.

RESULTS

P190B deficiency reduced tumor penetrance (53% of p190B+/-Neu mice vs. 100% of p190B+/+Neu mice formed tumors) and markedly delayed tumor onset by an average of 46 weeks. Tumor multiplicity was also decreased, but an increase in the number of preneoplastic lesions was detected indicating that p190B deficiency inhibited preneoplastic progression. Angiogenesis was decreased in the p190B heterozygous tumors, and expression of a potent angiogenic inhibitor, thrombospondin-1, was elevated in p190B+/-Neu mammary glands. Transplantation of p190B+/-Neu tumor fragments into wild-type recipients restored tumor angiogenesis. Strikingly, p190B+/+Neu tumor fragments were unable to grow when transplanted into p190B+/-Neu recipients.

CONCLUSIONS

These data suggest that p190B haploinsufficiency in the epithelium inhibits MMTV-Neu tumor initiation. Furthermore, p190B deficiency in the vasculature is responsible, in part, for the inhibition of MMTV-Neu tumor progression.

A distinct translation initiation mechanism generates cryptic peptides for immune surveillance

MHC class I molecules present a comprehensive mixture of peptides on the cell surface for immune surveillance. The peptides represent the intracellular protein milieu produced by translation of endogenous mRNAs. Unexpectedly, the peptides are encoded not only in conventional AUG initiated translational reading frames but also in alternative cryptic reading frames. Here, we analyzed how ribosomes recognize and use cryptic initiation codons in the mRNA. We find that translation initiation complexes assemble at non-AUG codons but differ from canonical AUG initiation in response to specific inhibitors acting within the peptidyl transferase and decoding centers of the ribosome. Thus, cryptic translation at non-AUG start codons can utilize a distinct initiation mechanism which could be differentially regulated to provide peptides for immune surveillance.

Pharmacology of novel heteroaromatic polycycle antibacterials

Heteroaromatic polycycle (HARP) compounds are a novel class of small (M(w), 600 to 650) DNA-binding antibacterials. HARP compounds exhibit a novel mechanism of action by preferentially binding to AT-rich sites commonly found in bacterial promoters and replication origins. Noncovalent binding in the minor groove of DNA results in inhibition of DNA replication and DNA-dependent RNA transcription and subsequent bacterial growth. HARP compounds have previously been shown to have potent in vitro activities against a broad spectrum of gram-positive organisms. The present report describes the extensive profiling of the in vitro and in vivo pharmacology of HARP antibacterials. The efficacies of representative compounds (GSQ-2287, GSQ-10547, and GSQ-11203), which exhibited good MIC activity, were tested in murine lethal peritonitis and neutropenic thigh infection models following intravenous (i.v.) administration. All compounds were efficacious in vivo, with potencies generally correlating with MICs. GSQ-10547 was the most potent compound in vitro and in vivo, with a 50% effective dose in the murine lethal peritonitis model of 7 mg/kg of body weight against methicillin-sensitive Staphylococcus aureus (MSSA) and 13 mg/kg against methicillin-resistant S. aureus (MRSA). In the neutropenic mouse thigh infection model, GSQ-11203 reduced the bacterial load (MRSA and MSSA) 2 log units following administration of a 25-mg/kg i.v. dose. In a murine lung infection model, treatment with GSQ-10547 at a dose of 50 mg/kg resulted in 100% survival. In addition to determination of efficacy in animals, the pharmacokinetic and tissue disposition profiles in animals following administration of an i.v. dose were determined. The compounds were advanced into broad safety screening studies, including screening for safety pharmacology, genotoxicity, and rodent toxicity. The results support further development of this novel class of antibiotics.