Faculty Bibliography

Tissue repair and healing remain among the most complicated processes that occur during postnatal life. Humans and other large organisms heal by forming fibrotic scar tissue with diminished function, while smaller organisms respond with scarless tissue regeneration and functional restoration. Well-established scaling principles reveal that organism size exponentially correlates with peak tissue forces during movement, and evolutionary responses have compensated by strengthening organ-level mechanical properties. How these adaptations may affect tissue injury has not been previously examined in large animals and humans. Here, we show that blocking mechanotransduction signaling through the focal adhesion kinase pathway in large animals significantly accelerates wound healing and enhances regeneration of skin with secondary structures such as hair follicles. In human cells, we demonstrate that mechanical forces shift fibroblasts toward pro-fibrotic phenotypes driven by ERK-YAP activation, leading to myofibroblast differentiation and excessive collagen production. Disruption of mechanical signaling specifically abrogates these responses and instead promotes regenerative fibroblast clusters characterized by AKT-EGR1.

Skin allo- and xenotransplantation are the standard treatment for major burns when donor sites for autografts are not available. The relationship between the immune response to foreign grafts and their impact on wound healing has not been fully elucidated. Here, we investigated changes in collagen architecture after xenogeneic implantation of human biologic scaffolds. We show that collagen deposition in response to the implantation of human split-thickness skin grafts (hSTSGs) containing live cells recapitulates normal skin architecture, whereas human acellular dermal matrix (ADM) grafts led to a fibrotic collagen deposition. We show that macrophage differentiation in response to hSTSG implantation is driven toward regenerative Trem2⁺ subpopulations and found that hydrogel delivery of these cells significantly accelerated wound closure. Our study identifies the preclinical therapeutic potential of Trem2⁺ macrophages to mitigate fibrosis and promote wound healing, providing a novel effective strategy to develop advanced cell therapies for complex wounds.

OBJECTIVE:Although some eye-tracking studies demonstrate atypical attention to faces by 6 months of age in autism spectrum disorder (ASD), behavioral studies in early infancy return largely negative results. We examined the effects of context and diagnosis on attention to faces during face-to-face live interactions in infants at high familial risk (HR) and low familial risk (LR) for ASD. METHOD:Participants were 6-, 9-, and 12-month-old siblings of children with ASD who were later determined to have ASD (n = 21), other developmental challenges (HR-C; n = 74), or typical development (TD) (HR-TD; n = 32), and low-risk, typically developing controls (LR-TD; n = 49). Infants were administered the social orienting probes task, consisting of five conditions: dyadic bid, song, peek-a-boo, tickle, and toy play. Attention to an unfamiliar examiner's face was coded by blinded raters from video recordings. RESULTS:At all ages, the ASD group spent less time looking at the examiner's face than the HR-C, HR-TD, and LR-TD groups during the Dyadic Bid and Tickle conditions (all p <.05), but not during the Song, Peek-a-Boo, or Toy Play conditions (all p >.23). Lower attention to faces during Dyadic Bid and Tickle conditions was significantly correlated with higher severity of autism symptoms at 18 months. CONCLUSION:During the prodromal stages of the disorder, infants with ASD exhibited subtle impairments in attention to faces of interactive partners during interactions involving eye contact and child-directed speech (with and without physical contact), but not in contexts involving singing, familiar anticipatory games, or toy play. Considering the convergence with eye-tracking findings on limited attention to faces in infants later diagnosed with ASD, reduced attention to faces of interactive partners in specific contexts may constitute a promising candidate behavioral marker of ASD in infancy.

The rising prevalence of autism spectrum disorder (ASD) necessitates a greater understanding of the academic experience of diagnosed children. The present study investigates several predictors of teacher-reported academic competence among a sample of elementary school children. All children in the sample were referred for an ASD evaluation and approximately half received a diagnosis. Children with and without ASD did not differ on overall academic competence, social skills, or problem behaviors. Regression analyses indicated that cognitive ability, social skills, and problem behaviors accounted for significant variance in academic competence. Moderation analyses indicated that the relations between the predictors and academic competence were comparable for children with and without ASD. Implications and future directions are discussed.

The mouse is the mammalian animal model of choice for many human diseases and biological processes. Developmental biology often requires staged-pregnant mice to determine evolving processes at various timepoints. Moreover, optimal and efficient breeding of model mice requires an assessment of timed pregnancies. Most commonly, mice are mated overnight, and the presence of a vaginal plug is determined; however, the positive predictive value of this technique is suboptimal, and one needs to wait to know if the mouse is truly pregnant. High-resolution ultrasound biomicroscopy is an effective and efficient tool for imaging: 1) Whether a mouse is pregnant; 2) What gestational stage the mouse has reached; and 3) Whether there are intrauterine losses. In addition to the embryos and fetuses, the investigator must also recognize common artifacts in the abdominal cavity so as not to mistake these for a gravid uterus. This article provides a protocol for imaging along with illustrative examples.

OBJECTIVE: It is well known that the embryo aneuploidy rate increases with women's age [1], but the effect of age on complex chromosomal abnormality (CCA) is less clear. Here, we addressed the relationship between maternal age and CCA with a retrospective cohort study. MATERIALS AND METHODS: We reviewed results of preimplantation genetic testing (PGT) by aCGH or NGS of embryo biopsies performed in an academic IVF unit between 2010 and 2019. We excluded PGT results from single gene disorder and egg donation cycles. CCA was defined as>=3 chromosome abnormalities (whole, partial and/or mosaic). Maternal age was categorized according to SART age groups: <35, 35-37, 38-40, 41-42, and >42 years. Statistical analyses were conducted using GraphPad Prism 8.
RESULT(S): 27,423 embryos were biopsied from 3,501 women aged 23 to 48 years. 4,740 embryos (16%) has CCA. Consistent with prior study [2], the most frequent chromosomes involved in CCA were 22, 16, 21 and 15, with incidences of 30.6%, 29.1%, 26.1% and 25.8% respectively. The number of chromosomal errors (from 3 to 42) involved in CCA did not correlate with maternal age (Spearman r = -0.0149, P = 0.3352). However, the rate of complex abnormal embryos tended to increase with advancing maternal age (9.7%, 11.2%, 10.9%, 24.8% and 43.6% in women aged < 35, 35-37, 38-40, 41-42, and > 42 years, respectively). Women over 40 years old had significantly higher rates of CCA compared to those under 40 years (Chisquare test, P < 0.0001). Surprisingly, the relationship between maternal age and CCA followed a U-shaped curve, decreasing from the 25 to 30 year old group (Pearson r = -0.831, P = 0.04) to the 30 to 35 year old group (Pearson r = 0.093, P = 0.861), then increased markedly in the 35 to 48 year old group (Pearson r = 0.921, P < 0.0001).
CONCLUSION(S):We found that CCA embryos share common features of aneuploidy, such as association with maternal age and preferential involvement of shorter chromosomes i.e. 22, 16, 21 and 15. Unexpectedly, our data showed that the relationship between CCA and maternal age assumes a U shape with increased rates at very young and very old ages. Both meiotic and mitotic errors contribute to chromosomal abnormality, and the contribution of each to CCA merits further investigation. IMPACT STATEMENT: The complex relationship between maternal age and embryo aneuploidy, which approximates a U-shape, may inform optimal timing of elective oocyte freezing and oocyte donation

OBJECTIVE: Over 15 million babies have been conceived by IVF, yet debate about its safety to offspring continues. We hypothesized that superovulation and in vitro fertilization (IVF) promote genomic changes, including altered telomere length (TL) and activation of the retrotransposon LINE-1 (L1), and tested this hypothesis in a mouse model. MATERIALS AND METHODS: Experimental laboratory study analyzing C57BL/6J mice produced blastocysts in vivo from natural mating cycles (N), in vivo following superovulation (S), or in vitro following superovulation (IVF). We also examined the effects of prolonged culture on TL and L1 in the IVF group. TL and L1 copy number were measured by Real Time PCR. Following log transformation, analysis of variance with Tukey post-test compared TL and L1 among the 3 groups. Students t test compared TL and L1 between embryos cultured for 120 vs. 96 hrs in the IVF group. Pvalue <0.05 was considered significant. Analyses were performed with SAS 9.4.
RESULT(S): In the IVF group, 10 replicates produced a fertilization rate of 90.52% (95% CI: 85.19-95.85), D4 blastocyst formation rate of 61.90% (95% CI: 52.62-71.19) and cumulative blastocyst rate (D4 plus D5) of 76.19% (CI: 68.04-84.34). TL in S (n=77; Mean: 1.50+/- 1.15; p 0.0007) and IVF (n=82; Mean: 1.72+/- 1.44; p <0.0001) exceeded that in N (n=16; Mean: 0.61+/- 0.27). L1 copy number in N (n=16; Mean: 0.80+/- 0.31) did not differ from S (n=77; Mean: 1.23+/- 0.75; p=0.1386) or IVF (n=82; Mean: 1.09+/- 1.16; p=0.6709). L1 copy number of embryos from S also did not differ significantly from IVF (n=82; Mean: 1.09+/- 1.16; p=0.0670). TL of blastocysts cultured 120h (n=14, Mean: 2.14 +/- 1.05) was significantly longer than that of embryos cultured for 96h (n=67, Mean: 1.63+/- 1.50, p=0.0414). L1 copy number of blastocysts cultured for 120h (n=15, Mean:1.71+/- 1.49) exceeded that of embryos cultured for 96h (n=67, Mean: 0.95+/- 1.03 p=0.0162).
CONCLUSION(S): Intriguingly ovarian hyperstimulation and IVF produced embryos with significantly longer telomeres compared to in vivo, natural cycle-produced embryos. The significance of this enriched telomere endowment for the health and longevity of offspring born from IVF merit future studies. The mechanism driving telomere lengthening in response to ovarian stimulation and IVF during early embryo development remains unclear, though may involve activation of L1. Recently we demonstrated a role for L1 in telomere elongation in preimplantation embryos, and Barbara McClintock's Nobel Prizing winning research previously identified activation of retrotransposons as a response to stress. Stress from IVF may elongate telomeres by activating L1. IMPACT STATEMENT: Millions of babies have been born following IVF, yet debate continues about its safety to offspring. We found genomic effects of IVF and ovarian stimulation in mice - telomere elongation and retrotransposon activation. Future studies should examine longevity and/or cancer risk in IVF offspring

OBJECTIVE: The causes of spontaneous abortion (SAB) following euploid embryo transfer (EET) remain poorly understood. Here we describe the frequency of aneuploidy in products of conception (POC) and endometrial dysfunction in women who miscarried after EET. MATERIALS AND METHODS: Between 1/2018 - 8/2020, 255 dilation and curettage (D&C) procedures were performed at a large academic IVF center for SAB following EET. Retrospective chart review was performed to identify D&Cs followed with genetic analysis of POCs. Information collected from the medical record included assessments of endometrial dysfunction based on Endometrial Receptivity Assay (ERA), CD138 for chronic endometritis (CE), and/or BCL6 for endometriosis. Exclusion criteria included an abnormal endometrial cavity on imaging. Demographic factors, clinical parameters and IVF/FET outcomes were reviewed. Additionally, retrospective chart review was performed of all ERAs completed at our institution from 12/2018-9/2020.
RESULT(S): Genetic analysis of 67 POCs after D&C following EET were identified. Fifty-nine POCs (88%) were euploid by SNP microarray. Eight (12%) of the POCs displayed genetic abnormalities: 3 trisomies, 2 partial duplications, 2 mosaic trisomies and 1 triploidy of paternal origin. Of the 51 patients who had endometrial biopsy (EMB), 28 (55%) had normal results. Twenty-three (45%) had abnormal results: 18 with CE, 2 with elevated BCL6 and 3 with pre-receptive ERA. The proportion of SABs unexplained by endometrial dysfunction or genetically abnormal POCs was 38% (26). A total of 44 patients underwent repeat EET. Eleven live births (LB) occurred, six after correction of endometrial dysfunction. Eight patients currently have ongoing pregnancy, 2 after treatment for CE. Three patients experienced repeat SAB, 1 following correction of pre-receptive ERA, and 1 after CE treatment. Four patients had implantation failure, 3 following normal EMB and 1 after treatment of CE. Two patients conceived spontaneously and delivered, 1 after treatment for CE, the other after a normal EMB. Upon review of all ERAs, 82 single EET following ERA guidance were identified. Fifty-nine percent (n=48) resulted in ongoing pregnancy or LB. There was no significant difference in ERA result or post ERA transfer outcome based on ethnicity (p= 0.7, p=0.4) or BMI (p= 0.8, 0.9), respectively. There was also no difference in post ERA transfer outcome based on blastocyst age (day 5 or 6) (p=0.5)
CONCLUSION(S): Aneuploidy and/or endometrial factor can contribute to SAB following EET. Aneuploid POCs could have arisen de novo and/or have passed undetected by trophectoderm biopsy and NGS. Our results are consistent with the 1-2% false negative rate reported for PGT-A. Further studies are needed to characterize the sub-chromosomal genetic variations associated with euploid embryo SABs, as well as endometrial function testing. IMPACT STATEMENT: The etiology behind failed EET may involve more discrete entities such as sub-chromosomal abnormalities in addition to aneuploidy and endometrial dysfunction