Intrinsic capacity and survival among older adults with gastrointestinal malignancies: The Cancer and Aging Resilience Evaluation registry.

BACKGROUND: Intrinsic capacity (IC) was introduced by the World Health Organization (WHO) as a marker of healthy aging, and is defined as the combination of an individual's physical, mental, and psychological capacities. This study aimed to assess IC via a patient-reported geriatric assessment (GA) and evaluate its association with survival among older adults with gastrointestinal (GI) malignancies. METHODS: Data were used from a single-institution prospective registry of older adults undergoing GA before cancer therapy. Key domains of IC (vitality, locomotion, and sensory [hearing and visual], psychological, and cognitive capacities) were captured via GA, and each was given a score of 0 or 1 (0, impaired) to compute the total IC score (range, 0-6, where 6 indicates no impairment and ≤5 indicates impairment in ≥1 domains). A frailty index (FI) was measured via the deficit accumulation method. Cox regression models and Kaplan-Meier curves were used to examine the impact of IC impairment on survival. RESULTS: The study included 665 patients; the median age was 68 years, 57.4% were men, and 72.9% were White. The median IC score was 4, and 79.3% of participants showed impairment in ≥1 domains of IC. Most commonly impaired domains were locomotion (48.7%) and vitality (43.9%). IC was inversely associated with FI (Spearman coefficient, -0.75; p < .001). IC impairment was associated with inferior overall survival (score, 4-5: adjusted hazard ratio [aHR], 1.7; 95% CI, 1.11-2.48; score, 2-3: aHR, 1.9; 95% CI, 1.30-2.85; score, 0-1: aHR, 1.9; 95% CI, 1.11-2.48). CONCLUSIONS: IC impairment is associated with frailty and reduced overall survival in older patients with GI malignancies. GA can be used to screen for IC impairment as recommended by the WHO. PLAIN LANGUAGE SUMMARY: The World Health Organization introduced intrinsic capacity as a marker of healthy aging. Intrinsic capacity is the combination of an individual's physical, mental, and psychological capacities. It contains six key domains: vitality, locomotion, and sensory (hearing and visual), psychological, and cognitive capacities. Older adults with cancer are susceptible to a decrease in intrinsic capacity as a result of cancer and the aging process. In this study, we aimed to assess the intrinsic capacity for patients with gastrointestinal cancer and also identify whether there exists any association of intrinsic capacity with overall survival. We identified that approximately 80% of this population had one or more impaired domains, and more intrinsic capacity impairment was associated with reduced overall survival.

The association between social vulnerability and geriatric assessment impairments among older adults with gastrointestinal cancers-The CARE Registry.

BACKGROUND: Older adults comprise the majority of patients with gastrointestinal (GI) cancer. Geriatric assessments (GAs) are recommended for older adults with cancer in part to detect aging-related impairments (e.g., frailty) associated with early mortality. Social factors like social vulnerability may also influence aging-related impairments. However, the association between social vulnerability and aging outcomes among older adults with cancer is understudied. METHODS: The authors included 908 older adults aged 60 years and older who were recently diagnosed with GI cancer undergoing GA at their first prechemotherapy visit to the University of Alabama at Birmingham oncology clinic. The primary exposure of interest was the social vulnerability index (SVI). Outcomes were frailty (frail vs. robust/prefrail) and total number of GA impairments (range, 0-13). The authors examined the association between SVI and outcomes using Poisson regression with robust variance estimation and generalized estimating equations. RESULTS: The median age at GA was 69 years (interquartile range, 64-75 years), 58.2% of patients were male, 22.6% were non-Hispanic Black, 29.1% had colorectal cancer, 28.2% had pancreatic cancer, and 70.3% had stage III/IV disease. Adjusting for age, sex, cancer type, and disease stage, each decile increase in the SVI was associated with an 8% higher prevalence of frailty (prevalence ratio, 1.08; 95% confidence interval, 1.05-1.11) and a 4% higher average count of total GA impairments (risk ratio, 1.04; 95% confidence interval, 1.02-1.06). The results were attenuated after further adjustment for race and education. CONCLUSIONS: Greater social vulnerability was associated with a higher prevalence of frailty and an increasing average number of GA impairments among older adults with GI cancers before systemic treatment. Intervening on social vulnerability may be a target for improving the risk of frailty and GA impairments, but associations of race and education should be further evaluated.

Understanding health outcome preferences of older adults diagnosed with multiple myeloma.

INTRODUCTION: Health outcome preferences of older adults with cancer vary based on burden/intensity of treatment and its impact on health outcomes such as survival, quality of life, and functional and cognitive well-being. We studied the association between age and health outcome preferences of adults with multiple myeloma (MM). MATERIALS AND METHODS: Using a single center prospective cohort study, we identified adults ≥50y with MM who underwent geriatric assessment (GA) within 30 days of initiating a new line of therapy. We assessed health outcome preferences using a nine-item health outcome preference scale where patients were asked to prioritize varying treatment outcomes in a Likert scale. We compared the response patterns for each item by age group (50-69y vs ≥70y) using Mantel-Haenszel chi-squared test. For items significant in bi-variable analysis, we built proportional odds models to study the association between age and health outcome preferences adjusting for sex, race, frailty, and high risk cytogenetics. RESULTS: We included 119 patients with a median age of 65y. Of these, 58% were male, 56% were non-Hispanic White, and 28% were frail. Older adults (≥70y) versus younger adults (50-69y) were more likely to prioritize health outcomes such as quality of life (53% vs. 34%), functional independence (74% vs. 33%), maintaining cognitive ability (79% vs. 54%), and living free from pain (50% vs 18%) over longer survival (all p values <0.05). In multivariable models, each one interquartile range (IQR) increase in age was associated with increased odds of prioritization of functional independence [adjusted odds ratio (aOR) 2.55, 95% confidence interval (CI) (1.44-4.53)], maintaining cognitive ability [aOR 1.75, 95% CI (1.01-3.02)], and willingness to take milder/ fewer treatments [aOR 2.40, 95% CI (1.36-4.26)] over longer survival. Similarly, each IQR increase in age was associated with decreased odds of prioritization of survival over quality of life [aOR 0.45, 95% CI (0.26-0.78)] and survival over being free from pain [aOR 0.39, 95% CI (0.22-0.69)]. DISCUSSION: Three out of four older adults (age ≥ 70y) with MM rated other outcomes, particularly functional and cognitive well-being, above survival. Determining the most significant treatment outcomes for older adults with MM can aid in establishing treatment goals and enhance shared decision-making.

Tracking cell layer contribution during repair of the tympanic membrane.

The tympanic membrane (i.e. eardrum) sits at the interface between the middle and external ear. The tympanic membrane is composed of three layers: an outer ectoderm-derived layer, a middle neural crest-derived fibroblast layer with contribution from the mesoderm-derived vasculature, and an inner endoderm-derived mucosal layer. These layers form a thin sandwich that is often perforated following trauma, pressure changes or middle ear inflammation. During healing, cells need to bridge the perforation in the absence of an initial scaffold. Here, we assessed the contribution, timing and interaction of the different layers during membrane repair by using markers and reporter mice. We showed that the ectodermal layer is retracted after perforation, before proliferating away from the wound edge, with keratin 5 basal cells migrating over the hole to bridge the gap. The mesenchymal and mucosal layers then used this scaffold to complete the repair, followed by advancement of the vasculature. Finally, differentiation of the epithelium led to formation of a scab. Our results reveal the dynamics and interconnections between the embryonic germ layers during repair and highlight how defects might occur.

Implementation of the Web-Enabled Cancer & Aging Resilience Evaluation (WeCARE) in an outpatient oncology setting.

INTRODUCTION: Although geriatric assessments (GAs) are recommended for use in older adults with cancer, their integration into oncology practice remain suboptimal. Here, we report our experience integrating web-enabled GA (WeCARE) into oncology practice as an augmented delivery method and provider interface format to overcome implementation barriers. MATERIALS AND METHODS: Older patients (≥60 years) with a gastro-intestinal (GI) malignancy presenting for an initial visit to medical oncology clinic at a single institution between December 7, 2021 and October 10, 2022 were contacted by staff two days in advance of their visits and sent a link to the WeCARE GA, rather than the paper version used previously. Results were directly embedded into the medical record. We describe our initial implementation outcomes and the results of a provider usability survey. RESULTS: Of 266 eligible patients, 221 (83.1%) were successfully contacted by telephone and 200 (75.2%) completed the WeCARE prior to their appointment. More than one phone call was required to make contact for 35.7% of patients, with a mean duration of phone conversation of 2.8 min. Most patients preferred email delivery to text (63% vs 31%); 4.5% were unable to access surveys due to inadequate technology, and 25.7% brought up additional logistical concerns. Among GI oncology providers surveyed, all six found the WeCARE tool and dashboard acceptable, appropriate, and feasible. However, only a third of providers often or always used the dashboard to inform treatment decisions and guide interventions. DISCUSSION: With nearly three-quarters of patients completing the WeCARE prior to their visits with minimal staff support and time required, this method of administration may be a viable format to overcome barriers to GA implementation. Additional work is needed to integrate the results meaningfully into clinical practice.

Association of emotional support with quality of life, mental health, and survival in older adults with gastrointestinal malignancies-Results from the CARE registry.

BACKGROUND: Emotional support (ES) is the most frequently reported support need among older adults with cancer. Yet, the association of ES with cancer outcomes is largely unknown. This study examined the association of ES with health-related quality of life (HRQoL), mental health, and survival among older adults with gastrointestinal (GI) malignancies. METHODS: We included newly diagnosed older adults (≥60 years) with GI cancer undergoing self-reported geriatric assessment at their first clinic visit. ES was measured using an adaptation of the Medical Outcomes Study (dichotomized adequate ES vs. inadequate ES). Outcomes included physical and mental HRQoL, anxiety, depression, and survival. Multivariable linear regression evaluated the association between ES and HRQoL scores. Multivariable logistic regression evaluated the association of ES with anxiety and depression. All models were adjusted for age at geriatric assessments, race, sex, and cancer type/stage. RESULTS: 795 participants were included. Median patient age was 68 years (IQR: 64-74), 58% were male, and most cancers were either colorectal (37.9%) or pancreatic (30.8%). Most (77.6%) had adequate ES. Patients with inadequate ES were more likely to be Black (31.5 vs. 20.8%, p = 0.005), disabled (24.1 vs. 10.4%, p < 0.001), widowed/divorced (54.2 vs. 24.8%, p < 0.001) and had lower physical and mental HRQoL t-scores (Physical ß: -3.35, 95% CI: -5.25, -1.46; Mental ß: -2.46, 95% CI: -4.11, -0.81) and higher odds of depression (aOR: 2.22, CI: 1.34-3.69). This study found no difference between those with adequate ES versus inadequate ES in the proportion of deaths within 1 year of diagnosis (24.3% vs. 24.2%, p = 0.966), or within 2 years of diagnosis (32.4% vs. 33.2%, p = 0.126). CONCLUSIONS: Older adults with inadequate ES have worse physical and mental HRQoL and higher odds of depression compared to those with adequate ES.

Spatiotemporal monitoring of hard tissue development reveals unknown features of tooth and bone development.

Mineralized tissues, such as bones or teeth, are essential structures of all vertebrates. They enable rapid movement, protection, and food processing, in addition to providing physiological functions. Although the development, regeneration, and pathogenesis of teeth and bones have been intensely studied, there is currently no tool to accurately follow the dynamics of growth and healing of these vital tissues in space and time. Here, we present the BEE-ST (Bones and tEEth Spatio-Temporal growth monitoring) approach, which allows precise quantification of development, regeneration, remodeling, and healing in any type of calcified tissue across different species. Using mouse teeth as model the turnover rate of continuously growing incisors was quantified, and role of hard/soft diet on molar root growth was shown. Furthermore, the dynamics of bones and teeth growth in lizards, frogs, birds, and zebrafish was uncovered. This approach represents an effective, highly reproducible, and versatile tool that opens up diverse possibilities in developmental biology, bone and tooth healing, tissue engineering, and disease modeling.

Pedomorphosis in the ancestry of marsupial mammals.

Within mammals, different reproductive strategies (e.g., egg laying, live birth of extremely underdeveloped young, and live birth of well-developed young) have been linked to divergent evolutionary histories. How and when developmental variation across mammals arose is unclear. While egg laying is unquestionably considered the ancestral state for all mammals, many long-standing biases treat the extreme underdeveloped state of marsupial young as the ancestral state for therian mammals (clade including both marsupials and placentals), with the well-developed young of placentals often considered the derived mode of development. Here, we quantify mammalian cranial morphological development and estimate ancestral patterns of cranial shape development using geometric morphometric analysis of the largest comparative ontogenetic dataset of mammals to date (165 specimens, 22 species). We identify a conserved region of cranial morphospace for fetal specimens, after which cranial morphology diversified through ontogeny in a cone-shaped pattern. This cone-shaped pattern of development distinctively reflected the upper half of the developmental hourglass model. Moreover, cranial morphological variation was found to be significantly associated with the level of development (position on the altricial-precocial spectrum) exhibited at birth. Estimation of ancestral state allometry (size-related shape change) reconstructs marsupials as pedomorphic relative to the ancestral therian mammal. In contrast, the estimated allometries for the ancestral placental and ancestral therian were indistinguishable. Thus, from our results, we hypothesize that placental mammal cranial development most closely reflects that of the ancestral therian mammal, while marsupial cranial development represents a more derived mode of mammalian development, in stark contrast to many interpretations of mammalian evolution.

Wnt signaling from Gli1-expressing apical stem/progenitor cells is essential for the coordination of tooth root development.

Stem cell regulation plays a crucial role during development and homeostasis. Here, an essential source of Wnts from Gli1+ stem/progenitor cells was identified in the murine molar. Loss of Wnt production in Gli1+ apical stem/progenitor cells led to loss of Axin2 at the root apex, mis-regulation of SOX9, loss of BMP and Hh signaling, and truncation of root development. In the absence of Wnt signals, the root epithelium lost its integrity and epithelial identity. This phenotype could be partially mimicked by loss of Sox9 in the Gli1 population. Stabilization of Wnt signaling in the apical papilla led to rapid unordered differentiation of hard tissues and fragmentation of the epithelial root sheath. Wnt signaling from Gli1+ stem/progenitor cells, therefore, orchestrates root development, coordinating mesenchymal and epithelial interactions via SOX9 to regulate stem/progenitor cell expansion and differentiation. Our results demonstrate that disparate stem/progenitor cell populations are unified in their fundamental signaling interactions.

Nuclear receptor Nr5a2 promotes diverse connective tissue fates in the jaw.

Organ development involves the sustained production of diverse cell types with spatiotemporal precision. In the vertebrate jaw, neural-crest-derived progenitors produce not only skeletal tissues but also later-forming tendons and salivary glands. Here we identify the pluripotency factor Nr5a2 as essential for cell-fate decisions in the jaw. In zebrafish and mice, we observe transient expression of Nr5a2 in a subset of mandibular postmigratory neural-crest-derived cells. In zebrafish nr5a2 mutants, nr5a2-expressing cells that would normally form tendons generate excess jaw cartilage. In mice, neural-crest-specific Nr5a2 loss results in analogous skeletal and tendon defects in the jaw and middle ear, as well as salivary gland loss. Single-cell profiling shows that Nr5a2, distinct from its roles in pluripotency, promotes jaw-specific chromatin accessibility and gene expression that is essential for tendon and gland fates. Thus, repurposing of Nr5a2 promotes connective tissue fates to generate the full repertoire of derivatives required for jaw and middle ear function.

Genetic Variants in Protein Tyrosine Phosphatase Non-Receptor Type 23 Are Responsible for Mesiodens Formation.

A mesiodens is a supernumerary tooth located in the midline of the premaxilla. To investigate the genetic cause of mesiodens, clinical and radiographic examination were performed on 23 family members of a two-generation Hmong family. Whole exome sequencing (WES) or Sanger sequencing were performed in 22 family members and two unrelated Thai patients with mesiodens. WES in the Hmong family revealed a missense mutation (c.1807G>A;p.Glu603Lys) in PTPN23 in seven affected members and six unaffected members. The mode of inheritance was autosomal dominance with incomplete penetrance (53.84%). Two additional mutations in PTPN23, c.2248C>G;p.Pro750Ala and c.3298C>T;p.Arg1100Cys were identified in two unrelated patients with mesiodens. PTPN23 is a regulator of endosomal trafficking functioning to move activated membrane receptors, such as EGFR, from the endosomal sorting complex towards the ESCRT-III complex for multivesicular body biogenesis, lysosomal degradation, and subsequent downregulation of receptor signaling. Immunohistochemical study and RNAscope on developing mouse embryos showed broad expression of PTPN23 in oral tissues, while immunofluorescence showed that EGFR was specifically concentrated in the midline epithelium. Importantly, PTPN23 mutant protein was shown to have reduced phosphatase activity. In conclusion, mesiodens were associated with genetic variants in PTPN23, suggesting that mesiodens may form due to defects in endosomal trafficking, leading to disrupted midline signaling.

Molecular profiling of the vestibular lamina highlights a key role for Hedgehog signalling.

The vestibular lamina (VL) forms the oral vestibule, creating a gap between the teeth, lips and cheeks. In a number of ciliopathies, formation of the vestibule is defective, leading to the creation of multiple frenula. In contrast to the neighbouring dental lamina, which forms the teeth, little is known about the genes that pattern the VL. Here, we establish a molecular signature for the usually non-odontogenic VL in mice and highlight several genes and signalling pathways that may play a role in its development. For one of these, the Sonic hedgehog (Shh) pathway, we show that co-receptors Gas1, Cdon and Boc are highly expressed in the VL and act to enhance the Shh signal from the forming incisor region. In Gas1 mutant mice, expression of Gli1 was disrupted and the VL epithelium failed to extend due to a loss of proliferation. This defect was exacerbated in Boc/Gas1 double mutants and could be phenocopied using cyclopamine in culture. Signals from the forming teeth, therefore, control development of the VL, coordinating the development of the dentition and the oral cavity.

Evolution and development of the mammalian jaw joint: Making a novel structure.

A jaw joint between the squamosal and dentary is a defining feature of mammals and is referred to as the temporomandibular joint (TMJ) in humans. Driven by changes in dentition and jaw musculature, this new joint evolved early in the mammalian ancestral lineage and permitted the transference of the ancestral jaw joint into the middle ear. The fossil record demonstrates the steps in the cynodont lineage that led to the acquisition of the TMJ, including the expansion of the dentary bone, formation of the coronoid process, and initial contact between the dentary and squamosal. From a developmental perspective, the components of the TMJ form through tissue interactions of muscle and skeletal elements, as well as through interaction between the jaw and the cranial base, with the signals involved in these interactions being both biomechanical and biochemical. In this review, we discuss the development of the TMJ in an evolutionary context. We describe the evolution of the TMJ in the fossil record and the development of the TMJ in embryonic development. We address the formation of key elements of the TMJ and how knowledge from developmental biology can inform our understanding of TMJ evolution.

Getting out of a mammalian egg: the egg tooth and caruncle of the echidna.

In the echidna, after development in utero, the egg is laid in the pouch and incubated for 10 days. During this time, the fetuses develop an egg tooth and caruncle to help them hatch. Using rare and unprecedented access to limited echidna pre- and post-hatching tissues, development of the egg tooth and caruncle were assessed by micro-CT, histology and immunofluorescence. Unlike therian tooth germs that develop by placode invagination, the echidna egg tooth developed by evagination, similar to the first teeth in some reptiles and fish. The egg tooth ankylosed to the premaxilla, rather than forming a tooth root with ligamentous attachment found in other mammals, with loss of the egg tooth associated with high levels of activity odontoclasts and apoptosis. The caruncle formed as a separate mineralisation from the adjacent nasal capsule, and as observed in birds and turtles, the nasal region epithelium on top of the nose expressed markers of cornification. Together, this highlights that the monotreme egg tooth shares many similarities with typical reptilian teeth, suggesting that this tooth has been conserved from a common ancestor of mammals and reptiles.

Active bystandership for law enforcement: Improving public safety by creating a policing culture of peer intervention.

In recent years, law enforcement agencies have come under severe criticism for officer misconduct and mistakes. As a result, changes have been imposed upon these agencies from outside of law enforcement. These changes include mandated policies, budget allocations, and in extreme cases, consent decrees. A national model launched in 2020, the Active Bystandership for Law Enforcement (ABLE) Project seeks to give agencies the tools they need to create culture change internally by embracing officer peer intervention as a tool to prevent misconduct, avoid mistakes, and promote health and wellness. This article describes the following regarding ABLE: (a) history and program development timeline, (b) programmatic structure and objectives, and (c) an examination of ABLE's potential to help law enforcement agencies create meaningful, positive culture change to improve public health and safety using active bystandership. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Mechanisms driving vestibular lamina formation and opening in the mouse.

The vestibular lamina (VL) forms as an epithelial outgrowth parallel to the dental lamina (DL) in the oral cavity. During late development, it opens to create a furrow that divides the dental tissue from the cheeks and lips and is known as the vestibule. Defects in this process lead to failure in the separation of the teeth from the lips and cheeks, including the presence of multiple frenula. In this paper, the development of the VL is followed in the mouse, from epithelial placode in the embryo to postnatal opening and vestibule formation. During early outgrowth, differential proliferation controls the curvature of the VL as it extends under the forming incisors. Apoptosis plays a role in thinning the deepest part of the lamina, while terminal differentiation of the epithelium, highlighted by the expression of loricrin and flattening of the nuclei, predates the division of the VL into two to create the vestibule. Development in the mouse is compared to the human VL, with respect to the relationship of the VL to the DL, VL morphology and mechanisms of opening. Overall, this paper provides insight into an understudied part of the oral anatomy, shedding light on how defects could form in this region.

The interconnected relationships between middle ear bulla size, cavitation defects, and chronic otitis media revealed in a syndromic mouse model.

High incidence of chronic otitis media is associated with human craniofacial syndromes, suggesting that defects in the formation of the middle ear and associated structures can have a knock-on effect on the susceptibility to middle ear inflammation. Patients with branchio-oto-renal (BOR) syndrome have several defects in the ear leading to both sensorineural and conductive hearing loss, including otitis media. 40% of BOR syndrome cases are due to Eya1 haploinsufficiency, with mouse models affecting Eya1, mimicking many of the defects found in patients. Here, we characterize the onset, consequences, and underlying causes of chronic otitis media in Eya1 heterozygous mice. Cavitation defects were evident in these mice from postnatal day (P)11 onwards, with mesenchyme around the promontory and attic regions of the middle ear space. This mesenchyme was still prominent in adult Eya1 heterozygous mice, while the wild-type littermates had fully aerated ears from P14 onwards. MicroCT analysis highlighted a significantly smaller bulla, confirming the link between bulla size defects and the ability of the mesenchyme to retract successfully. Otitis media was observed from P14, often presenting unilaterally, resulting in hyperplasia of the middle ear mucosa, expansion of secretory cells, defects in the motile cilia, and changes in basal epithelial cell markers. A high incidence of otitis media was identified in older mice but only associated with ears with retained mesenchyme. To understand the impact of the environment, the mouse line was rederived onto a super-clean environment. Cavitation defects were still evident at early stages, but these generally resolved over time, and importantly, no signs of otitis media were observed at 6 weeks. In conclusion, we show that a small bulla size is closely linked to defects in cavitation and the presence of retained mesenchyme. A delay in retraction of the mesenchyme predates the onset of otitis media, making the ears susceptible to its development. Early exposure to OM appears to exacerbate the cavitation defect, with mesenchyme evident in the middle ear throughout the animal's life. This highlights that permanent damage to the middle ear can arise as a consequence of the early onset of OM.

Endothelial cells during craniofacial development: Populating and patterning the head.

Major organs and tissues require close association with the vasculature during development and for later function. Blood vessels are essential for efficient gas exchange and for providing metabolic sustenance to individual cells, with endothelial cells forming the basic unit of this complex vascular framework. Recent research has revealed novel roles for endothelial cells in mediating tissue morphogenesis and differentiation during development, providing an instructive role to shape the tissues as they form. This highlights the importance of providing a vasculature when constructing tissues and organs for tissue engineering. Studies in various organ systems have identified important signalling pathways crucial for regulating the cross talk between endothelial cells and their environment. This review will focus on the origin and migration of craniofacial endothelial cells and how these cells influence the development of craniofacial tissues. For this we will look at research on the interaction with the cranial neural crest, and individual organs such as the salivary glands, teeth, and jaw. Additionally, we will investigate the methods used to understand and manipulate endothelial networks during the development of craniofacial tissues, highlighting recent advances in this area.

Mutations in LRP6 highlight the role of WNT signaling in oral exostoses and dental anomalies.

OBJECTIVE: The objective of this study was to investigate molecular etiologies of oral exostoses and dental anomalies in 14 patients from eight families. METHODS: Oral and radiographic examinations were performed on every patient. Whole exome and Sanger sequencing were performed on DNA of the patients, the unaffected parents and unaffected siblings. LRP6 mutant proteins were modeled and analyzed. RESULTS: Five mutations in LRP6, including four missense (p.Glu72Lys, p.Lys82Asn, Tyr418His, and p.Ile773Val) and one nonsense mutation (p.Arg32Ter), were identified. These mutations have not been reported to be associated with dental anomalies or oral exostoses. Oral features included a variety of oral exostoses (7 of the 14 patients), root defects (6 of the 14 patients), and tooth agenesis (5 of the 14 patients). Less common dental anomalies included microdontia, tooth fusion, odontomas, and mesiodens. Analysis of the protein models of the five LRP6 mutations shed light on their likely impact on LRP6 protein structure and function. CONCLUSION: Fourteen patients with five LRP6 mutations, including two recurrent mutations and three novel ones, are reported. Our study shows for the first time that mutations in LRP6 are associated with mesiodens, fusion of teeth, odontomas, microdontia, long roots, molars with unseparated roots, and taurodontism.

A mesenchymal to epithelial switch in Fgf10 expression specifies an evolutionary-conserved population of ionocytes in salivary glands.

Fibroblast growth factor 10 (FGF10) is well established as a mesenchyme-derived growth factor and a critical regulator of fetal organ development in mice and humans. Using a single-cell RNA sequencing (RNA-seq) atlas of salivary gland (SG) and a tamoxifen inducible Fgf10CreERT2:R26-tdTomato mouse, we show that FGF10pos cells are exclusively mesenchymal until postnatal day 5 (P5) but, after P7, there is a switch in expression and only epithelial FGF10pos cells are observed after P15. Further RNA-seq analysis of sorted mesenchymal and epithelial FGF10pos cells shows that the epithelial FGF10pos population express the hallmarks of ancient ionocyte signature Forkhead box i1 and 2 (Foxi1, Foxi2), Achaete-scute homolog 3 (Ascl3), and the cystic fibrosis transmembrane conductance regulator (Cftr). We propose that epithelial FGF10pos cells are specialized SG ionocytes located in ducts and important for the ionic modification of saliva. In addition, they maintain FGF10-dependent gland homeostasis via communication with FGFR2bpos ductal and myoepithelial cells.