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TEM of the corneal stroma and endothelium. Representative images from C57BLKS/J, C57BL/6J, and SJL/J eyes. (A-C) There were no notable differences in architecture of the stromal lamellae or keratocytes. Rather, differences in CCT appeared to be due to an increased number of structurally normal-appearing lamellae. (D-I) Collagen fibers in cross section from the anterior (D-F) and posterior (G-I) cornea are well organized and of uniform diameter. (J-L) Thickness of Descemet's membrane (arrowheads) follows overall thickness of the cornea, although it is only responsible for a small portion of the corneal thickness.
Source publication
Central corneal thickness (CCT) exhibits broad variability. For unknown reasons, CCT also associates with diseases not typically considered corneal, particularly glaucoma. The purpose of this study was to test the strain dependence of CCT variability among inbred mice and identify cellular and molecular factors associated with differing CCT.
Method...
Contexts in source publication
Context 1
... additional anatomic observations were made with TEM (Fig. 5). First, differing thickness of the stroma appeared to be due to an increased number of lamellae, and not to the thickness of each individual lamellae (Figs. 5A-C). Second, collagen fiber diameters were well organized and of uniform diameter among all three strains in both the anterior (Figs. 5D-F) and posterior (Figs. 5G-I) corneal stroma. Collagen fiber diameters in the anterior/posterior cornea for each strain were 31.5/32.4, 32.5/31.8, and 31.6/31.8 nm (n 2, 1, and 2 eyes of mice 100 to 120 days of age; C57BLKS/J, C57BL/6J, and SJL/J, respectively). Finally, the thickness of Descemet's mem- brane correlated with overall corneal thickness (Figs. 5J-L), contributing 1.7%, 1.7%, and 2.0% to the overall corneal thick- ness (C57BLKS/J, C57BL/6J, and SJL/J, respectively). In sum, the findings of these comparative analyses demonstrated by multiple methods that the differences in CCT between these strains was not a simple consequence of an underlying corneal disease, but rather, that the differences reflected extremes of the normal physiological range of CCT exhibited by ...
Context 2
... additional anatomic observations were made with TEM (Fig. 5). First, differing thickness of the stroma appeared to be due to an increased number of lamellae, and not to the thickness of each individual lamellae (Figs. 5A-C). Second, collagen fiber diameters were well organized and of uniform diameter among all three strains in both the anterior (Figs. 5D-F) and posterior (Figs. 5G-I) corneal stroma. Collagen fiber diameters in the anterior/posterior cornea for each strain were 31.5/32.4, 32.5/31.8, and 31.6/31.8 nm (n 2, 1, and 2 eyes of mice 100 to 120 days of age; C57BLKS/J, C57BL/6J, and SJL/J, respectively). Finally, the thickness of Descemet's mem- brane correlated with overall corneal thickness (Figs. 5J-L), contributing 1.7%, 1.7%, and 2.0% to the overall corneal thick- ness (C57BLKS/J, C57BL/6J, and SJL/J, respectively). In sum, the findings of these comparative analyses demonstrated by multiple methods that the differences in CCT between these strains was not a simple consequence of an underlying corneal disease, but rather, that the differences reflected extremes of the normal physiological range of CCT exhibited by ...
Context 3
... additional anatomic observations were made with TEM (Fig. 5). First, differing thickness of the stroma appeared to be due to an increased number of lamellae, and not to the thickness of each individual lamellae (Figs. 5A-C). Second, collagen fiber diameters were well organized and of uniform diameter among all three strains in both the anterior (Figs. 5D-F) and posterior (Figs. 5G-I) corneal stroma. Collagen fiber diameters in the anterior/posterior cornea for each strain were 31.5/32.4, 32.5/31.8, and 31.6/31.8 nm (n 2, 1, and 2 eyes of mice 100 to 120 days of age; C57BLKS/J, C57BL/6J, and SJL/J, respectively). Finally, the thickness of Descemet's mem- brane correlated with overall corneal thickness (Figs. 5J-L), contributing 1.7%, 1.7%, and 2.0% to the overall corneal thick- ness (C57BLKS/J, C57BL/6J, and SJL/J, respectively). In sum, the findings of these comparative analyses demonstrated by multiple methods that the differences in CCT between these strains was not a simple consequence of an underlying corneal disease, but rather, that the differences reflected extremes of the normal physiological range of CCT exhibited by ...
Citations
... [56][57][58] This is possibly due to the strains of mice, age, and the measuring techniques used. 56,57,59 For example, using confocal microscopy, Zhang et al. 56 reported a CCT of 170 μm in the BALB/c mice whereas Schulz et al. 57 reported a CCT of 106 ± 3.45 μm in the same strain using an optical low coherence reflectometer. Moreover, using a histological approach, Henriksson et al. 58 reported a CCT of 122.68 ± 4.8 μm, 137.02 ± 14.0 μm, and 134.16 ± 12.9 μm in 129/SVJ, C57BL/6, and BALB/c mice, respectively. ...
... Moreover, using a histological approach, Henriksson et al. 58 reported a CCT of 122.68 ± 4.8 μm, 137.02 ± 14.0 μm, and 134.16 ± 12.9 μm in 129/SVJ, C57BL/6, and BALB/c mice, respectively. Using ultrasound pachymetry, Lively et al. 59 reported wide variations in CCT among 17 strains of mice with different genetic backgrounds. Of note, C57BL/6J mice, the most widely used inbred strain, had a CCT of 100.8 ± 5.7 μm. ...
... Of note, C57BL/6J mice, the most widely used inbred strain, had a CCT of 100.8 ± 5.7 μm. 59 In line with these findings, the significance of CCT measurements for our gene trap mice using SD-OCT in comparison with the transgenic models could be attributed to the differences in the genetic makeup of the three models. ...
PURPOSE. It is necessary to establish a mouse model of keratoconus (KC) for research and therapy. We aimed to determine corneal phenotypes in 3 Ppip5k2 mouse models.
METHODS. Central corneal thickness (CCT) was determined using spectral domain optical coherence tomography (SD-OCT) in Ppip5k2 +/Kˆ(n = 41 eyes), Ppip5k2 Kˆ/Kˆ(n = 17 eyes) and 2 knock-in mice, Ppip5k2 S419A/+ (n = 54 eyes) and Ppip5k2 S419A/S419A (n = 18 eyes), and Ppip5k2 D843S/+ (n = 42 eyes) and Ppip5k2 D843S/D843S (n = 44 eyes) at 3 and 6 months. Pachymetry maps were generated using the Mouse Corneal Analysis Program (MCAP) to process OCT images. Slit lamp biomicroscopy was used to determine any corneal abnormalities, and, last, hematoxylin and eosin (H&E) staining using corneal sections from these animals was used to examine morphological changes.
RESULTS. CCT significantly decreased from 3 to 6 months in the Ppip5k2 +/Kˆa nd Ppip5k2 Kˆ/Kˆm ice compared to their littermate controls. OCT-based pachymetry maps revealed abnormally localized thinning in all three models compared to their wild-type (WT) controls. Slit lamp examinations revealed corneal abnormalities in the form of bullous keratopathy, stromal edema, stromal scarring, deep corneal neovascularization, and opacities in the heterozygous/homozygous mice of the three models in comparison with their controls. Corneal histological abnormalities, such as epithelial thickening and stromal layer damage, were observed in the heterozygous/homozygous mice of the three models in comparison with the WT controls.
CONCLUSIONS. We have identified phenotypic and histological changes in the corneas of three mouse lines that could be relevant in the development of animal models of KC.
... [56][57][58] This is possibly due to the strains of mice, age, and the measuring techniques used. 56,57,59 For example, using confocal microscopy, Zhang et al. 56 reported a CCT of 170 μm in the BALB/c mice whereas Schulz et al. 57 reported a CCT of 106 ± 3.45 μm in the same strain using an optical low coherence reflectometer. Moreover, using a histological approach, Henriksson et al. 58 reported a CCT of 122.68 ± 4.8 μm, 137.02 ± 14.0 μm, and 134.16 ± 12.9 μm in 129/SVJ, C57BL/6, and BALB/c mice, respectively. ...
... Moreover, using a histological approach, Henriksson et al. 58 reported a CCT of 122.68 ± 4.8 μm, 137.02 ± 14.0 μm, and 134.16 ± 12.9 μm in 129/SVJ, C57BL/6, and BALB/c mice, respectively. Using ultrasound pachymetry, Lively et al. 59 reported wide variations in CCT among 17 strains of mice with different genetic backgrounds. Of note, C57BL/6J mice, the most widely used inbred strain, had a CCT of 100.8 ± 5.7 μm. ...
... Of note, C57BL/6J mice, the most widely used inbred strain, had a CCT of 100.8 ± 5.7 μm. 59 In line with these findings, the significance of CCT measurements for our gene trap mice using SD-OCT in comparison with the transgenic models could be attributed to the differences in the genetic makeup of the three models. ...
Purpose
It is necessary to establish a mouse model of keratoconus (KC) for research and therapy. We aimed to determine corneal phenotypes in 3 Ppip5k2 mouse models.
Methods
Central corneal thickness (CCT) was determined using spectral domain optical coherence tomography (SD-OCT) in Ppip5k2+/K^ (n = 41 eyes), Ppip5k2K^/K^ (n = 17 eyes) and 2 knock-in mice, Ppip5k2S419A/+ (n = 54 eyes) and Ppip5k2S419A/S419A (n = 18 eyes), and Ppip5k2D843S/+ (n = 42 eyes) and Ppip5k2D843S/D843S (n = 44 eyes) at 3 and 6 months. Pachymetry maps were generated using the Mouse Corneal Analysis Program (MCAP) to process OCT images. Slit lamp biomicroscopy was used to determine any corneal abnormalities, and, last, hematoxylin and eosin (H&E) staining using corneal sections from these animals was used to examine morphological changes.
Results
CCT significantly decreased from 3 to 6 months in the Ppip5k2+/K^ and Ppip5k2K^/K^ mice compared to their littermate controls. OCT-based pachymetry maps revealed abnormally localized thinning in all three models compared to their wild-type (WT) controls. Slit lamp examinations revealed corneal abnormalities in the form of bullous keratopathy, stromal edema, stromal scarring, deep corneal neovascularization, and opacities in the heterozygous/homozygous mice of the three models in comparison with their controls. Corneal histological abnormalities, such as epithelial thickening and stromal layer damage, were observed in the heterozygous/homozygous mice of the three models in comparison with the WT controls.
Conclusions
We have identified phenotypic and histological changes in the corneas of three mouse lines that could be relevant in the development of animal models of KC.
... In the control group C1, the corneal epithelium, stroma, and endothelium showed average thicknesses of 37.4 µm, 64.2 µm, and 4.5 µm, respectively, and the average total corneal thickness was 104.2 µm. The baseline corneal thickness in C1 is consistent with other studies for C57BL/6 mice, which measured an average thickness of 100.8 ± 5.7 µm [47]. Compared with the C1 group, the total corneal thickness increased 4-fold and 3-fold in group C2 and group C4, respectively, (Fig. 3(e)), stromal thicknesses increased 5-fold and 4-fold in the C2 and C4 groups, respectively (Fig. 3(f)), and epithelium thickness increased 2-fold in the C2 group ( Fig. 3(g)). ...
We developed a multiscale optical imaging workflow, integrating and correlating visible-light optical coherence tomography, confocal laser scanning microscopy, and single-molecule localization microscopy to investigate mouse cornea damage from the in-vivo tissue level to the nanoscopic single-molecule level. We used electron microscopy to validate the imaged nanoscopic structures. We imaged wild-type mice and mice with acute ocular hypertension and examined the effects of Rho-kinase inhibitor application. We defined four types of intercellular tight junction structures as healthy, compact, partially-distorted, and fully-distorted types by labeling the zonula occludens-1 protein in the corneal endothelial cell layer. We correlated the statistics of the four types of tight junction structures with cornea thickness and intraocular pressure. We found that the population of fully-distorted tight junctions correlated well with the level of corneal edema, and applying Rho-kinase inhibitor reduced the population of fully-distorted tight junctions under acute ocular hypertension. Together, these data point to the utility of multiscale optical imaging in revealing fundamental biology relevant to disease and therapeutics.
... The genetic background influences inflammatory reactions after infections (Thurston et al., 1998;Zou et al., 2012), the recruitment of macrophages (Stein et al., 2006), as well as cytokine (Zou et al., 2012) and chemokine secretion (Stein et al., 2006). In the cornea, differences in corneal thickness (Lively et al., 2010), macrophages numbers (Maruyama et al., 2012), the resting limbal blood vessel area (Chan et al., 2004), and the blood vessel growth in response to FGF-2 and VEGF (Rohan et al., 2000) have been observed depending on the genetic background. Since the discovery of lymphatic markers, research into genetic heterogeneity of lymphangiogenesis has gained more attention (Nakao et al., 2010;Regenfuss et al., 2010). ...
Historically, the eye has been considered as an organ free of lymphatic vessels. In recent years, however, it became evident, that lymphatic vessels or lymphatic-like vessels contribute to several ocular pathologies at various peri- and intraocular locations. The aim of this review is to outline the pathogenetic role of ocular lymphatics, the respective molecular mechanisms and to discuss current and future therapeutic options based thereon. We will give an overview on the vascular anatomy of the healthy ocular surface and the molecular mechanisms contributing to corneal (lymph)angiogenic privilege. In addition, we present (i) current insights into the cellular and molecular mechanisms occurring during pathological neovascularization of the cornea triggered e.g. by inflammation or trauma, (ii) the role of lymphatic vessels in different ocular surface pathologies such as dry eye disease, corneal graft rejection, ocular graft versus host disease, allergy, and pterygium, (iii) the involvement of lymphatic vessels in ocular tumors and metastasis, and (iv) the novel role of the lymphatic-like structure of Schlemm's canal in glaucoma. Identification of the underlying molecular mechanisms and of novel modulators of lymphangiogenesis will contribute to the development of new therapeutic targets for the treatment of ocular diseases associated with pathological lymphangiogenesis in the future. The preclinical data presented here outline novel therapeutic concepts for promoting transplant survival, inhibiting metastasis of ocular tumors, reducing inflammation of the ocular surface, and treating glaucoma. Initial data from clinical trials suggest first success of novel treatment strategies to promote transplant survival based on pretransplant corneal lymphangioregression.
... Cross-sections were analyzed under a bright-field microscope at 20X magnification. Only central corneal sections were chosen and the average of the two measurements of each sample was used for analysis using ImageJ software (NIH, US) (Elbasiony et al., 2022;Lively et al., 2010). The epithelial, stromal and total corneal thickness measurements were illustrated in Supplementary Fig. 1. ...
Chemical injury of the cornea results in epithelial defect and subsequent stromal scarring and infection. Our study aims to evaluate the effectiveness of pre-treatment of Lycium barbarum polysaccharide (LBP) in promoting corneal re-epithelialization after alkaline burn. The corneas of C57BL/6J mice were pre-treated with topical phosphate-buffered saline or LBP (0.2/2/20 mg/mL) for 7 days, following by 0.1M sodium hydroxide injury for 30 s and washing with distilled water for another 30 s. Area of epithelial defect and thickness of cornea were evaluated. Inflammatory cytokines and water channel expression levels were assessed using immunohistochemistry and Western blot. Compared to the injury group, mice with 2 mg/mL LBP pre-treatment revealed a significant decrease in fluorescein stained area after injury (p = 0.025), with increased epithelial layer thickness (p = 0.004). The corneal opacity was significantly reduced in the group with 2 mg/mL LBP pre-treatment followed by injury (p = 0.02). The expression of matrix metalloproteinase 12 (p = 0.033), platelet derived growth factor-BB (p = 0.031), and aquaporin 5 (p = 0.022) resulted in a decrease in expression level in group with 2 mg/mL LBP pre-treatment. Our results showed that 2 mg/mL LBP, with no apoptotic effect on corneal cells, promoted corneal epithelial growth and minimized disruption of the collagen architecture after injury in vivo. We suggest that LBP, as a natural Traditional Chinese Medicine, may potentially be a novel topical pre-treatment option for patients highly susceptible to ocular injury.
... This pachymeter allows only a 5-degree angulation margin to permit the best measurements, which helps to achieve a more consistent perpendicular probe position. 13 All measurements were performed by an experienced ophthalmic technician between 10.00 am and 12.00 pm and at least 2 hours after eye-opening to keep diurnal variation to a minimum. The first measurement was omitted, and the probe remained touching the cornea until continuous measurements were grouped within 5 μm. ...
Background:
There is increasing research on the aging process of the cornea and its effect on the corneal parameters measured objectively. Nevertheless, the association of corneal epithelial thickness (CET) with age has yet to be fully illustrated.
Purpose:
We aimed to measure CET in healthy subjects to determine its age-related variation by using an ultrasound device.
Patients and methods:
A total of one hundred and three subjects were enrolled in this study and grouped according to age: Group < 30 years, 31-40 years, 41-50 years, 51-60 years, 61-70 years, and > 71 years. The CET and total central corneal thickness (CCT) of each subject were measured by the Sonogage Corneo-Gage Plus 2 (Cleveland, Ohio) ultrasound pachymeter. The relationships between thickness values, laterality, age groups, and gender were analyzed using the Jonckheere-Terpstra test. The Partial correlation test was employed to assess the effect of age on the CET and CCT.
Results:
The mean CET was 47.88±1.15μm, with no statistically significant gender-related difference between right and left eyes. In addition, the CCT difference detected between female and male eyes was insignificant. The difference in mean CET across age groups was statistically significant (p =0.029). The difference in mean CET of left eyes across age groups was statistically significant (p=0.031). The mean CET and left CET of the oldest group were significantly thinner than the younger groups.
Conclusion:
Ultrasound pachymeter of the corneal epithelium demonstrated that there was no correlation between age and CCT, or gender. The CET becomes thinner with age in the central zone in both genders and there is no difference between males and females. Based on these results, age has a negative effect on CET. These findings could offer further insight into age-related changes in the cornea.
... Fig. 5C). Color maps were based on averaging murine CCT values measured across several mouse strains (Lively et al., 2010) and spanned ± 5 of the reported standard deviations (107.6 ± 45 μm). The sub-micrometer digit was due to averaging and not a reflection of the pachymeter resolution. ...
The majority of the eye's refractive power lies in the cornea, and pathological changes in its shape can affect vision. Small animal models offer an unparalleled degree of control over genetic and environmental factors that can help elucidate mechanisms of diseases affecting corneal shape. However, there is not currently a method to characterize the corneal shape of small animal eyes with topography or pachymetry maps, as is done clinically for humans. We bridge this gap by demonstrating methods using optical coherence tomography (OCT) to generate the first topography and pachymetry (thickness) maps of mouse corneas. Radii of curvature acquired using OCT were validated using calibration spheres as well as in vivo mouse corneas with a mouse keratometer. The resulting topography and pachymetry maps are analogous to those used diagnostically in clinic and potentially allow for characterization of genetically modified mice that replicate key features of human corneal disease.
... However, there remains inconsistency with respect to the reported impact of aging on other ocular surface parameters, such as corneal thickness, where some studies have reported no age-related changes, 17,18 and others have shown an increased thickness compared with young mice. 19 In addition, the effects of aging on corneal immune responses, in particular the number, distribution, and morphology of resident epithelial dendritic cells (DCs), is unclear. ...
Abstract
PURPOSE:
Aging is a risk factor for dry eye disease. The aim of this study was to investigate if aging is associated with a range of signs of dry eye disease, including tear hyperosmolarity, reduced nerve density, and increased dendritic cell number, in mice.
METHOD:
Healthy C57BL/6 female mice, aged 2 months (young, n = 10) and 22 months (aged, n = 11) were used. Clinical assessments included corneal sensitivity (Cochet-Bonnet esthesiometry), tear secretion (Phenol red thread test), tear film osmolarity (TearLab osmometer), and corneal thickness (optical coherence tomography). The sum length of the corneal superficial terminals and sub-basal nerves, density of vertical nerve projections, and density and tree area of resident epithelial dendritic cells, were assessed using immunofluorescence and confocal microscopy.
RESULTS:
Aged mice had significantly higher tear secretion, lower corneal sensitivity, and a thicker corneal stroma but thinner epithelium. There was no significant intergroup difference for tear osmolarity. Aged mice showed a significantly lower sum length of nerves in the superficial terminals and sub-basal plexus, relative to young mice. Dendritic cell density and morphology were similar in both groups.
CONCLUSIONS:
In mice, aging is associated with higher tear secretion and corneal epithelial thinning, together with lower corneal nerve density and sensitivity. However, aging was not significantly associated with changes to tear osmolarity or dendritic cell density or size, despite a significant reduction in total nerve length. These findings demonstrate that aged mice exhibit some changes to ocular surface parameters that parallel the anomalies evident in dry eye disease.
... Finally, using SD-OCT there was no detected difference in central corneal thickness (P ¼ 0.69) or anterior chamber depth (P ¼ 0.52), compared to the average previously measured for C57BL/6J mice. 36 FIGURE 3. Negative masking. (A) A representative wild-type littermate actogram shows how a 1-hour pulse of light applied 1 hour after lights off alters the amount of wheel running in a dose-dependent manner. ...
Purpose:
The R345W mutation in EFEMP1 causes malattia leventinese, an autosomal dominant eye disease with pathogenesis similar to an early-onset age-related macular degeneration. In mice, Efemp1R345W does not cause detectable degeneration but small subretinal deposits do accumulate. The purpose of this study was to determine whether there were abnormal responses to light at this presymptomatic stage in Efemp1R345W mice.
Methods:
Responses to light were assessed by visual water task, circadian phase shifting, and negative masking behavior. The mechanism of abnormal responses was investigated by anterior eye exam, electroretinogram, melanopsin cell quantification, and multielectrode recording of retinal ganglion cell activity.
Results:
Visual acuity was not different in Efemp1R345W mice. However, amplitudes of circadian phase shifting (P = 0.016) and negative masking (P < 0.0001) were increased in Efemp1R345W mice. This phenotype was not explained by anterior eye defects or amplified outer retina responses. Instead, we identified increased melanopsin-generated responses to light in the ganglion cell layer of the retina (P < 0.01).
Conclusions:
Efemp1R345W increases the sensitivity to light of behavioral responses driven by detection of irradiance. An amplified response to light in melanopsin-expressing intrinsically photosensitive retinal ganglion cells (ipRGCs) is consistent with this phenotype. The major concern with this effect of the malattia leventinese mutation is the potential for abnormal regulation of physiology by light to negatively affect health.
... We compared murine corneal thickness with that of other mammals with different body sizes (evolutionary allometric analysis). We extracted central cornea thickness of adult elephant, human, pig, cow, cat, dog, rabbit, and mice [18][19][20][21][22][23][24][25] as well as their reported body weights [20,21,[23][24][25][26][27][28] from the literature, and performed allometric analysis (Fig 4). We found that the log-log plot of the corneal thickness versus body weight shows a linear trend. ...
... We compared murine corneal thickness with that of other mammals with different body sizes (evolutionary allometric analysis). We extracted central cornea thickness of adult elephant, human, pig, cow, cat, dog, rabbit, and mice [18][19][20][21][22][23][24][25] as well as their reported body weights [20,21,[23][24][25][26][27][28] from the literature, and performed allometric analysis (Fig 4). We found that the log-log plot of the corneal thickness versus body weight shows a linear trend. ...
... Our study showed that the murine central corneal thickness was highly strain-dependent. Our data supported previous studies demonstrating that the central corneal thickness of C57BL6J mice was thinner than that of BALB/c mice under weight adjustment [25]. In addition, we revealed ECD was also strongly influenced by genetic backgrounds, suggesting that the genes may influence the physiologic attrition of ECD. ...
Corneal thickness is tightly regulated by its boundary endothelial and epithelial layers. The regulated set-point of corneal thickness likely shows inter-individual variations, changes by age, and response to stress. Using anterior segment-optical coherence tomography, we measure murine central corneal thickness and report on body size scaling of murine central corneal thickness during aging. For aged-matched mice, we find that corneal thickness depends on sex and strain. To shed mechanistic insights into these anatomical changes, we measure epithelial layer integrity and endothelial cell density during the life span of the mice using corneal fluorescein staining and in vivo confocal microscopy, respectively and compare their trends with that of the corneal thickness. Cornea thickness increases initially (1 month: 114.7 ± 3.0 μm, 6 months: 126.3 ± 1.6 μm), reaches a maximum (9 months: 129.3 ± 4.4 μm) and then reduces (12 months: 127 ± 2.9 μm, 13 months: 119.5 ± 7.6 μm, 14 months: 110.6 ± 10.6 μm), while the body size (weight) increases with age. We find that endothelial cell density reduces from 2 months old to 8 months old as the mice age and epithelial layer accumulates damages within this time frame. Finally, we compare murine corneal thickness with those of several other mammals including humans and show that corneal thickness has an allometric scaling with body size. Our results have relevance for organ size regulation, translational pharmacology, and veterinary medicine.
