RMRP-related short stature: A report of six additional Japanese individuals with cartilage hair hypoplasia and literature review

Biallelic pathogenic variants in RMRP, the gene encoding the RNA component of RNase mitochondrial RNA processing enzyme complex, have been reported in individuals with cartilage hair hypoplasia (CHH). CHH is prevalent in Finnish and Amish populations due to a founder pathogenic variant, n.71A > G. Based on the manifestations in the Finnish and Amish individuals, the hallmarks of CHH are prenatal-onset growth failure, metaphyseal dysplasia, hair hypoplasia, immunodeficiency, and other extraskeletal manifestations. Herein, we report six Japanese individuals with CHH from four families. All probands presented with moderate short stature with mild metaphyseal dysplasia or brachydactyly. One of them had hair hypoplasia and the other immunodeficiency. By contrast, the affected siblings of two families showed only mild short stature. We also reviewed all previously reported 13 Japanese individuals. No n.71A > G allele was detected. The proportions of Japanese versus Finnish individuals were 0% versus 70% for birth length < -2.0 SD, 84% versus 100% for metaphyseal dysplasia and 26% versus 88% for hair hypoplasia. Milder manifestations in the Japanese individuals may be related to the difference of genotypes. The mildest form of CHH phenotypes is mild short stature without overt skeletal alteration or extraskeletal manifestation and can be termed "RMRP-related short stature".

Functional variants in a TTTG microsatellite on 15q26.1 cause familial nonautoimmune thyroid abnormalities

Insufficient thyroid hormone production in newborns is referred to as congenital hypothyroidism. Multinodular goiter (MNG), characterized by an enlarged thyroid gland with multiple nodules, is usually seen in adults and is recognized as a separate disorder from congenital hypothyroidism. Here we performed a linkage analysis of a family with both nongoitrous congenital hypothyroidism and MNG and identified a signal at 15q26.1. Follow-up analyses with whole-genome sequencing and genetic screening in congenital hypothyroidism and MNG cohorts showed that changes in a noncoding TTTG microsatellite on 15q26.1 were frequently observed in congenital hypothyroidism (137 in 989) and MNG (3 in 33) compared with controls (3 in 38,722). Characterization of the noncoding variants with epigenomic data and in vitro experiments suggested that the microsatellite is located in a thyroid-specific transcriptional repressor, and its activity is disrupted by the variants. Collectively, we presented genetic evidence linking nongoitrous congenital hypothyroidism and MNG, providing unique insights into thyroid abnormalities.

Endothelial cells regulate alveolar morphogenesis by constructing basement membranes acting as a scaffold for myofibroblasts

Alveologenesis is a spatially coordinated morphogenetic event, during which alveolar myofibroblasts surround the terminal sacs constructed by epithelial cells and endothelial cells (ECs), then contract to form secondary septa to generate alveoli in the lungs. Recent studies have demonstrated the important role of alveolar ECs in this morphogenetic event. However, the mechanisms underlying EC-mediated alveologenesis remain unknown. Herein, we show that ECs regulate alveologenesis by constructing basement membranes (BMs) acting as a scaffold for myofibroblasts to induce septa formation through activating mechanical signaling. Rap1, a small GTPase of the Ras superfamily, is known to stimulate integrin-mediated cell adhesions. EC-specific Rap1-deficient (Rap1iECKO) mice exhibit impaired septa formation and hypo-alveolarization due to the decreased mechanical signaling in myofibroblasts. In Rap1iECKO mice, ECs fail to stimulate integrin β1 to recruit Collagen type IV (Col-4) into BMs required for myofibroblast-mediated septa formation. Consistently, EC-specific integrin β1-deficient mice show hypo-alveolarization, defective mechanical signaling in myofibroblasts, and disorganized BMs. These data demonstrate that alveolar ECs promote integrin β1-mediated Col-4 recruitment in a Rap1-dependent manner, thereby constructing BMs acting as a scaffold for myofibroblasts to induce mechanical signal-mediated alveologenesis. Thus, this study unveils a mechanism of organ morphogenesis mediated by ECs through intrinsic functions.

Novel 8-wire basket catheter is useful for endoscopic removal of common bile duct stones up to 10 mm: A multicenter prospective study

BACKGROUND/PURPOSE

Endoscopic treatment of common bile duct (CBD) stones involves the use of basket or balloon catheters; however, what is the appropriate device remains controversial. In this study we aimed to prospectively evaluate the usefulness of a novel 8-wire helical basket (8WB) catheter made of Nitinol for the removal of CBD stones ≤10 mm.

METHODS

We conducted a multicenter prospective trial. Patients with CBD stones ≤10 mm were enrolled. The primary endpoint was the rate of complete stone removal within 10 min using the 8WB. The number of cases was determined using a previous study of stone removal by a conventional basket catheter as a historical control.

RESULTS

A total of 155 patients were enrolled and 139 were ultimately included in the analysis. Patients with a single stone were the most common (84 cases, 60.4%), with a median maximum stone diameter of 5 mm. The median stone removal time using the 8WB was 6 min. The complete stone removal rate was 95.0% (132/139). Adverse events were observed in 14 patients (10.1%).

CONCLUSIONS

The novel 8WB catheter is useful in the treatment of CBD stones ≤10 mm, presenting a high complete stone removal rate in this study.

TRIAL REGISTRATION NUMBER

jRCT1032200324.

Development of sexual dimorphism of skeletal muscles through the adrenal cortex, caused by androgen-induced global gene suppression

The zona fasciculata (zF) in the adrenal cortex contributes to multiple physiological actions through glucocorticoid synthesis. The size, proliferation, and glucocorticoid synthesis characteristics are all female biased, and sexual dimorphism is established by androgen. In this study, transcriptomes were obtained to unveil the sex differentiation mechanism. Interestingly, both the amount of mRNA and the expressions of nearly all genes were higher in females. The expression of Nr5a1, which is essential for steroidogenic cell differentiation, was also female biased. Whole-genome studies demonstrated that NR5A1 regulates nearly all gene expression directly or indirectly. This suggests that androgen-induced global gene suppression is potentially mediated by NR5A1. Using Nr5a1 heterozygous mice, whose adrenal cortex is smaller than the wild type, we demonstrated that the size of skeletal muscles is possibly regulated by glucocorticoid synthesized by zF. Taken together, considering the ubiquitous presence of glucocorticoid receptors, our findings provide a pathway for sex differentiation through glucocorticoid synthesis.

Effect of soft denture liners on complete denture treatments: A systematic review

PURPOSE

This systematic review examined the effectiveness of soft denture relining (SDR) materials.

STUDY SELECTION

A comprehensive search of MEDLINE, Cochrane Library, and ICHUSHI was conducted up to July 26, 2020. Target outcomes were patient satisfaction, oral health-related quality of life (OHRQOL), masticatory ability (MA), denture functional duration, residual ridge resorption (RRR), and microbial contamination. An organization specializing in literature searches performed the reference searches, and two reviewers independently selected the literature sources, extracted the data, and assessed the risk of bias. The reviewers resolved any disagreements concerning the assortment of literature sources through discussion. SDR included acrylic- and silicone-based materials, which were evaluated separately.

RESULTS

Reviewers selected 7, 5, 11, 1, 4, and 6 studies to assess patient satisfaction, OHRQOL, MA, functional duration, RRR, and microbial contamination, respectively. The results confirmed that SDR improved patient satisfaction, OHRQOL, MA, and RRR. However, the functional duration of SDR material is shorter than that of hard denture relining (HDR) or acrylic resin material. Furthermore, SDR material is more susceptible to microbial contamination in the long term. The risk of bias for the included studies tended to be high because of specific issues (difficulty in blinding SDR versus HDR).

CONCLUSIONS

For patients who wear complete dentures, SDR often provides beneficial outcomes such as pain reduction and recovery from MA. However, caution should be exercised regarding their use owing to insufficient functional duration and the possibility of microbial contamination during long-term use.

Single-Exon Deletions of ZNRF3 Exon 2 Cause Congenital Adrenal Hypoplasia

CONTEXT

Primary adrenal insufficiency (PAI) is a life-threatening condition characterized by the inability of the adrenal cortex to produce sufficient steroid hormones. E3 ubiquitin protein ligase zinc and ring finger 3 (ZNRF3) is a negative regulator of Wnt/β-catenin signaling. R-spondin 1 (RSPO1) enhances Wnt/β-catenin signaling via binding and removal of ZNRF3 from the cell surface.

OBJECTIVE

This work aimed to explore a novel genetic form of PAI.

METHODS

We analyzed 9 patients with childhood-onset PAI of biochemically and genetically unknown etiology using array comparative genomic hybridization. To examine the functionality of the identified single-exon deletions of ZNRF3 exon 2, we performed three-dimensional (3D) structure modeling and in vitro functional studies.

RESULTS

We identified various-sized single-exon deletions encompassing ZNRF3 exon 2 in 3 patients who showed neonatal-onset adrenal hypoplasia with glucocorticoid and mineralocorticoid deficiencies. Reverse-transcriptase polymerase chain reaction (RT-PCR) analysis showed that the 3 distinct single-exon deletions were commonly transcribed into a 126-nucleotide deleted mRNA and translated into 42-amino acid deleted protein (ΔEx2-ZNRF3). Based on 3D structure modeling, we predicted that interaction between ZNRF3 and RSPO1 would be disturbed in ΔEx2-ZNRF3, suggesting loss of RSPO1-dependent activation of Wnt/β-catenin signaling. Cell-based functional assays with the TCF-LEF reporter showed that RSPO1-dependent activation of Wnt/β-catenin signaling was attenuated in cells expressing ΔEx2-ZNRF3 as compared with those expressing wild-type ZNRF3.

CONCLUSION

We provided genetic evidence linking deletions encompassing ZNRF3 exon 2 and congenital adrenal hypoplasia, which might be related to constitutive inactivation of Wnt/β-catenin signaling by ΔEx2-ZNRF3.

DHX37 Variant is One of Common Genetic Causes in Japanese Patients with Testicular Regression Syndrome / Partial Gonadal Dysgenesis without Müllerian Derivatives

INTRODUCTION

The testicular regression syndrome (TRS) is a form of differences of sex development (DSD) in which the testes differentiate and function during early embryonic development, but subsequently regress. The clinical phenotype of TRS often overlaps with that of partial gonadal dysgenesis (PGD). Previous studies have demonstrated a causal association between TRS/PGD and heterozygous missense variants of DHX37.

METHODS

We enrolled 11 Japanese 46,XY individuals (from 10 families) with TRS/PGD who exhibited undetected or hypoplastic testes, Müllerian duct regression, and low serum testosterone or anti-Müllerian hormone levels. The subjects underwent targeted sequencing of 36 known causative genes for DSD, PCR-based Sanger sequencing of DHX37, or whole exome sequencing.

RESULTS

Previously described pathogenic variants or novel nonsense variants (SRY, NR5A1, and DMRT1) were observed in four out of 10 families. Additionally, we identified two heterozygous rare variants of DHX37 in four families: a previously reported pathogenic variant (c.923G>A, p.Arg308Gln) in three and a novel likely pathogenic variant (c.1882A>C, p.Thr628Pro) in one. The external genitalia of patients with the DHX37 variants varied from female-type to male-type without micropenis. Eighty percent of Japanese patients with TRS/PGD had monogenic disorders including DHX37 variant being the most commonly identified (40%). The external or internal genital phenotype of TRS/PGD overlaps between DHX37 variant carriers and others.

CONCLUSIONS

DHX37 variant is one of common genetic causes in Japanese patients with TRS/PGD without Müllerian derivatives. Genetic test is helpful in detecting DHX37-related TRS/PGD, because of the phenotypic diversity of the external genitalia in this disorder.

Development of an optogenetics tool, Opto-RANK, for control of osteoclast differentiation using blue light

Optogenetics enables precise regulation of intracellular signaling in target cells. However, the application of optogenetics to induce the differentiation of precursor cells and generate mature cells with specific functions has not yet been fully explored. Here, we focused on osteoclasts, which play an important role in bone remodeling, to develop a novel optogenetics tool, Opto-RANK, which can manipulate intracellular signals involved in osteoclast differentiation and maturation using blue light. We engineered Opto-RANK variants, Opto-RANKc and Opto-RANKm, and generated stable cell lines through retroviral transduction. Differentiation was induced by blue light, and various assays were conducted for functional analysis. Osteoclast precursor cells expressing Opto-RANK differentiated into multinucleated giant cells on light exposure and displayed upregulation of genes normally induced in differentiated osteoclasts. Furthermore, the differentiated cells exhibited bone-resorbing activities, with the possibility of spatial control of the resorption by targeted light illumination. These results suggested that Opto-RANK cells differentiated by light possess the features of osteoclasts, both morphological and functional. Thus, Opto-RANK should be useful for detailed spatiotemporal analysis of intracellular signaling during osteoclast differentiation and the development of new therapies for various bone diseases.

Incidence and Risk Factors for Adrenal Crisis in Pediatric-onset Adrenal Insufficiency: A Prospective Study

PURPOSE

To determine the incidence and risk factors for adrenal crisis (AC) in patients with pediatric-onset adrenal insufficiency (AI).

MATERIALS AND METHODS

This multicenter, prospective cohort study conducted in Japan enrolled patients diagnosed with AI at ≤ 15 years of age. The incidence of AC was calculated as events per person-year (PY), and risk factors for AC were assessed using Poisson regression multivariable analysis.

RESULTS

The study population comprised 349 patients (164 male, 185 female) with a total follow-up of 961 PY. The median age at enrollment was 14.3 years (interquartile range [IQR] 8.5-21.2 years), and the median follow-up was 2.8 years (IQR 2.2-3.3 years). Of these patients, 213 (61%) had primary AI and 136 (39%) had secondary AI. Forty-one AC events occurred in 31 patients during the study period. The calculated incidence of AC was 4.27 per 100 PY (95% confidence interval [CI] of 3.15-5.75). Poisson regression analysis identified younger age at enrollment (relative risk [RR] 0.93 [95% CI 0.89-0.97]) and increased number of infections (RR 1.17 [95% CI 1.07-1.27]) as significant risk factors. Female sex (RR 0.99 [95% CI 0.53-1.86]), primary AI (RR 0.65 [95 % CI 0.30-1.41]), or equivalent dosage of hydrocortisone per square meter of body area (RR 1.02 [95% CI 0.96-1.08]) was not a significant risk factor.

CONCLUSION

A substantial proportion of patients with pediatric-onset AI experience AC. Younger age and an increased number of infections are independent risk factors for developing AC in these patients.

Rap1 small GTPase is essential for maintaining pulmonary endothelial barrier function in mice

Vascular permeability is dynamically but tightly controlled by vascular endothelial (VE)-cadherin-mediated endothelial cell-cell junctions to maintain homeostasis. Thus, impairments of VE-cadherin-mediated cell adhesions lead to hyperpermeability, promoting the development and progression of various disease processes. Notably, the lungs are a highly vulnerable organ wherein pulmonary inflammation and infection result in vascular leakage. Herein, we showed that Rap1, a small GTPase, plays an essential role for maintaining pulmonary endothelial barrier function in mice. Endothelial cell-specific Rap1a/Rap1b double knockout mice exhibited severe pulmonary edema. They also showed vascular leakage in the hearts, but not in the brains. En face analyses of the pulmonary arteries and 3D-immunofluorescence analyses of the lungs revealed that Rap1 potentiates VE-cadherin-mediated endothelial cell-cell junctions through dynamic actin cytoskeleton reorganization. Rap1 inhibits formation of cytoplasmic actin bundles perpendicularly binding VE-cadherin adhesions through inhibition of a Rho-ROCK pathway-induced activation of cytoplasmic nonmuscle myosin II (NM-II). Simultaneously, Rap1 induces junctional NM-II activation to create circumferential actin bundles, which anchor and stabilize VE-cadherin at cell-cell junctions. We also showed that the mice carrying only one allele of either Rap1a or Rap1b out of the two Rap1 genes are more vulnerable to lipopolysaccharide (LPS)-induced pulmonary vascular leakage than wild-type mice, while activation of Rap1 by administration of 007, an activator for Epac, attenuates LPS-induced increase in pulmonary endothelial permeability in wild-type mice. Thus, we demonstrate that Rap1 plays an essential role for maintaining pulmonary endothelial barrier functions under physiological conditions and provides protection against inflammation-induced pulmonary vascular leakage.

A case of 46,XY complete gonadal dysgenesis with a novel missense variant in SRY

Disorders of sex development (DSD) with mild external genital abnormalities may be diagnosed after puberty. Here, we report a case of 46,XY complete gonadal dysgenesis with a novel missense variant in sex-determining region Y (SRY), diagnosed after primary amenorrhea. A 15-yr-old patient presented to our gynecology department with a chief complaint of amenorrhea. The patient was diagnosed with a 46,XY karyotype, and SRY gene positivity. Gonadotropin levels were high, whereas testosterone levels were low. A pelvic magnetic resonance imaging (MRI) revealed a hypoplastic uterus; however, no gonads could be identified. Laparoscopy revealed bilateral streak gonads, fallopian tube-like structures, and the uterus. The gonads were removed based on the risk of gonadal malignancy. Comprehensive genetic analysis of DSD revealed a previously unreported SRY variant, c.271A>T, p.Ser91Cys, and in silico analysis predicted the variant to be pathogenic. The patient was diagnosed with 46,XY complete gonadal dysgenesis with a novel missense variant in SRY. The patient continued female hormone replacement therapy and experienced breast enlargement and cyclic menstruation. Determining the etiology of DSD can be difficult, causing anxiety in patients and their families. In addition to surgical scrutiny, genetic analysis is important to aid in diagnosis and reassure patients and their families.

Fibroblast growth factor 23 levels in cord and peripheral blood during early neonatal period as possible predictors of affected offspring of X-linked hypophosphatemic rickets: report of three female cases from two pedigrees

OBJECTIVES

The role of serum fibroblast growth factor 23 (FGF23) level in early neonatal period on the diagnosis of X-linked hypophosphatemic rickets (XLH) remains unclear.

CASE PRESENTATION

Two female patients from the first pedigree had an affected mother, and the other female from the second pedigree had an affected father. In all three cases, FGF23 levels were high in cord blood and peripheral blood at day 4-5. Additionally, the FGF23 levels considerably increased from birth to day 4-5. We identified a PHEX pathogenic variant and initiated treatment during infancy in each case.

CONCLUSIONS

In neonates with a parent diagnosed as PHEX-associated XLH, FGF23 in cord blood and peripheral blood at day 4-5 may be useful markers for predicting the presence of XLH.

Effects of 5-fluorouracil Co-administration on Blood Pressure in Patients Maintained on Antihypertensives: a Retrospective Case Series

This study aimed to investigate the possible drug-drug interactions (DDIs) of 5-FU with antihypertensives metabolised by CYP3A4 and 2C9, using blood pressure (BP) as a pharmacodynamic (PD) parameter. Patients who received 5-FU in combination with antihypertensives metabolised by CYP3A4 or 2C9, specifically, a) amlodipine, nifedipine, or amlodipine + nifedipine, b) candesartan or valsartan, or c) amlodipine + candesartan, amlodipine + losartan, or nifedipine + valsartan, (Group A, n = 20) were identified. Patients who received 5-FU with WF and antihypertensives, specifically, a) amlodipine or b) amlodipine + telmisartan, amlodipine + candesartan, or amlodipine + valsartan, (Group B, n = 5) or 5-FU alone (Group C, n = 25) were also identified and analysed as a comparator and control group, respectively. Regarding the peak BP levels during chemotherapy, there was a significant increase in both SBP (P < 0.0002 and 0.0013) and DBP (P = 0.0243 and 0.0032) in Groups A and C, respectively (Tukey-Kramer test). In contrast, although SBP also increased in Group B during chemotherapy, the change was not statistically significant and there was a decrease in DBP. The significant increase in SBP can be attributed to chemotherapy-induced hypertension by 5-FU or other drugs in the chemotherapeutic regimens. However, when comparing the lowest BP levels during chemotherapy, there was a decrease in SBP and DBP in all groups from the baseline values. The median time to peak and lowest BP was at least 2 weeks and 3 weeks, respectively, for all groups, suggesting that a BP lowering effect was observed following the offset of the initial chemotherapy-induced hypertension. At least 1 month after 5-FU chemotherapy, the SBP and DBP returned to baseline values in all groups. Since Group B also showed a significant increase in PT-INR, possibly demonstrating 5-FU inhibition of CYP activity and, consequently, of WF metabolism, it is likely that 5-FU also inhibited the metabolism of the antihypertensive drugs. The findings suggest possible DDIs between 5-FU and antihypertensives metabolised by CYP3A4.

Analysis of COVID-19 mRNA Vaccine-induced Mouth Ulcers Using the Japanese Adverse Drug Event Report Database

There are case reports of mouth ulcers caused by the coronavirus disease 2019 (COVID-19) messenger ribonucleic acid (mRNA) vaccine; however, the actual number and characteristics of cases are unknown. Therefore, we examined this issue using the Japanese Adverse Drug Event Report (JADER), a large Japanese database. We calculated the reported odds ratio (ROR) of drugs that may be specifically associated with mouth ulcers and assumed that a signal was present if the lower limit of the calculated ROR's 95% confidence interval (CI) was > 1. In addition, the time to symptom onset after administration of the COVID-19 mRNA and influenza HA vaccines was investigated. We found that the JADER database contained 4,661 mouth ulcer cases between April 2004 and March 2022. The COVID-19 mRNA vaccine was the eighth most common causative drug for mouth ulcers, with 204 reported cases. The ROR was 1.6 (95% CI, 1.4-1.9) and a signal was detected. There were 172 mouthulcer cases associated with the Pfizer-BioNTech's COVID-19 mRNA vaccine, 76.2% of which were female. The outcome was no unrecovered cases with the influenza HA vaccine, whereas the COVID-19 mRNA vaccine showed unrecovered cases (Pfizer-BioNTech: 12.2%, Moderna: 11.1%). The median time-to-onset of the mouth ulcers was two days for the COVID-19 mRNA vaccine and one day for the influenza HA vaccine, indicating that mouth ulcers caused by the COVID-19 mRNA vaccine were delayed adverse events. In this study, the COVID-19 mRNA vaccine was shown to cause mouth ulcers in a Japanese population.

Novel regulatory mechanisms underlying angiogenesis during wound healing revealed by fluorescence-based live-imaging in zebrafish

Angiogenesis is a dynamic morphogenetic process that refers to the growth of new blood vessels from the pre-existing vessels and is critical for tissue repair during wound healing. In adult normal tissues, quiescent endothelial cells and pericytes maintain vascular integrity, whereas angiogenesis is immediately induced upon tissue injury, thereby forming neovascular networks to maintain homeostasis. However, impaired angiogenesis results in development of chronic and non-healing wounds in various diseases such as diabetes and peripheral artery diseases. Zebrafish are a vertebrate model organism widely used for studying many medical and life science fields. Indeed, the molecular and cellular mechanisms underlying regulation of wound angiogenesis have recently been studied by performing fluorescence-based live-imaging of adult zebrafish. In this review, we describe how endothelial cells and pericytes establish neovascular networks during wound angiogenesis and also introduce a novel role of blood flow-driven intraluminal pressure in regulating angiogenesis during wound healing.

Room-Temperature Continuous-Wave Microcavity Lasers from Solution-Processed Smooth Quasi-2D Perovskite Films with Low Thresholds

Continuous-wave (CW) lasing in quasi-two-dimensional (2D) perovskite-based distributed feedback cavities has been achieved at room temperature; however, CW microcavity lasers comprising distributed Bragg reflectors (DBRs) have rarely been prepared using solution-processed quasi-2D perovskite films because the roughness of perovskite films significantly increases intersurface scattering loss in the microcavity. Herein, high-quality spin-coated quasi-2D perovskite gain films were prepared using an antisolvent to reduce roughness. The highly reflective top DBR mirrors were deposited via room-temperature e-beam evaporation to protect the perovskite gain layer. Lasing emission of the prepared quasi-2D perovskite microcavity lasers under CW optical pumping was clearly observed at room temperature, featuring a low threshold of ∼1.4 W cm^-2 and beam divergence of ∼3.5°. It was concluded that these lasers originated from weakly coupled excitons. These results elucidate the importance of controlling the roughness of quasi-2D films to achieve CW lasing, thus facilitating the design of electrically pumped perovskite microcavity lasers.

Utility of 5-aminolaevulinic acid fluorescence-guided endoscopic biopsy for malignant mesothelioma in a cat and dog

Malignant mesothelioma (MM) is uncommon in cats and dogs and can be challenging to diagnose. Adequate tissue sampling is required for superior diagnostic accuracy. Protoporphyrin IX, a metabolite of 5-aminolaevulinic acid (5-ALA), is a photosensitiser for photodynamic diagnosis (PDD). To the best of our knowledge, no study has reported the use of 5-ALA-PDD to detect MM in veterinary medicine. The present study describes the use of 5-ALA-PDD for MM diagnosis in a cat and dog, as well as the effectiveness of intracavitary chemotherapy. We evaluated the use of PDD with 5-ALA hydrochloride (5-ALA-PDD) in two cases of MM. A 12-year-old cat presented with a 1-month history of respiratory distress, and a 9-year-old dog presented with a 3-month history of mild abdominal distention. We endoscopically biopsied lesions in both the cases using 5-ALA-PDD. Histopathological examination revealed mesothelioma, and immunohistochemical staining was positive for calretinin. Both patients were treated with carboplatin. The cat died of respiratory failure. Although, the dog's condition improved 21 days after the first chemotherapeutic drug administration, the dog died on day 684 owing to cardiac-related issues. 5-ALA-PDD is thus, safe and feasible for the diagnosis of MM in veterinary medicine.

Two Japanese Infants With Hypothyroidism Following Exposure to Iodinated Contrast Media

We report 2 Japanese infants with hypothyroidism requiring levothyroxine (LT4) replacement therapy following exposure to iodinated contrast media (ICM). Patient 1 was born at 32 weeks gestation. He had congenital heart disease and underwent contrast-enhanced computed tomography (CT) on day 22 (estimated amount of iodine: 600 mg/kg/dose). The newborn mass screening showed normal thyrotropin (thyroid-stimulating hormone; TSH) levels at day 4, but high TSH and low free thyroxine levels on retest at day 44. LT4 replacement therapy was administered on days 46 to 74. No hypothyroidism requiring LT4 replacement therapy was observed afterward. The ultrasonography showed a hypoplastic thyroid gland. Patient 2 was born full-term. She had congenital heart disease and underwent contrast-enhanced CT on day 52 (estimated amount of iodine: 1500 mg/kg/dose). The newborn mass screening showed normal TSH levels on day 4, but high TSH levels on retest on day 62. LT4 replacement therapy was administered from day 65 to 3 years of age. Genetic analysis showed a heterozygous variant of DUOX2. Exposure to ICM can result in hypothyroidism, requiring LT4 replacement therapy. The severity of hypothyroidism may depend on risk factors, such as genetic predisposition, preterm birth, thyroid hypoplasia, or early exposure to ICM.

Potential benefit of rapid genetic testing for Pallister–Hall syndrome

Pallister-Hall syndrome (PHS) is defined as a group of characteristic manifestations caused by a monoallelic GLI3 pathogenic variant. A two-month-old infant was referred to our institution because of undetermined sex. The infant had atypical genitalia with postaxial polysyndactyly, a hypothalamic mass, and an imperforate anus. We identified a known pathogenic variant of the GLI3 gene within one week and diagnosed the infant with PHS. The parents assigned the infant as male, considering the 46,XY karyotype, normal testosterone secretion, possible male identity, and the natural history of PHS. In infants with atypical genitalia and other malformations, such as polydactyly, a hypothalamic mass, or an imperforate anus, rapid GLI3 testing may provide information for planning lifelong management, including sex assignment.

Continuous glucose monitoring in an infant with panhypopituitarism having hypoglycemia on growth hormone therapy

OBJECTIVES

The usefulness of continuous glucose monitoring (CGM) in infants with panhypopituitarism (PH) having hypoglycemia is yet to be explored. The potential adverse effects of growth hormone (GH) replacement therapy, such as hyperglycemia, cannot be comprehensively evaluated using the conventional measurement.

CASE PRESENTATION

A 2-month-old infant with PH, including severe GH deficiency, had hypoglycemia despite frequent feeding. Glucose levels were monitored using CGM before and after GH replacement therapy. The proportion of time for hypoglycemia decreased from 4.9 to 0% (p<0.017). Hyperglycemia did not increase. The CGM method did not contribute to any adverse events requiring intervention. Our patient only experienced minor bleeding and no episode of cellulitis.

CONCLUSIONS

CGM is useful in controlling glucose levels in infants with hypoglycemia and PH.

An elderly patient with 17α-hydroxylase deficiency misdiagnosed as primary aldosteronism: a case report

BACKGROUND

17α-hydroxylase deficiency (17OHD) is a rare autosomal recessive disorder. Aldosterone levels are usually low in patients with 17OHD. However, among the approximately 150 cases of 17OHD reported to date, aldosterone levels were not low in all cases. Therefore, some 17OHD cases may have been misdiagnosed as primary aldosteronism (PA) cases. Often before puberty, 17OHD is diagnosed because of abnormal genital morphology and menstrual irregularities. However, we report a very rare case of 17OHD in an elderly patient with a high aldosterone/renin ratio (ARR) similar to that in PA.

CASE PRESENTATION

A 63-year-old Japanese woman was transferred to our medical facility for the evaluation of bilateral adrenal hypertrophy, which was incidentally discovered during an abdominal examination after cholecystectomy. The patient had hypokalemia and a high aldosterone/renin ratio. Her medical history included hypertension and right intracerebral capsular hemorrhage at the age of 30 years. Additional testing revealed low cortisol, high adrenocorticotropic hormone, and low testosterone and dehydroepiandrosterone sulfate, indicating congenital adrenal hyperplasia. Genetic analysis revealed a mutation in the CYP17A1 gene and a karyotype of 46, XY; hence, she was diagnosed with 17OHD.

CONCLUSION

17OHD can resemble PA. The combination of a high ARR and low cortisol level should trigger the consideration of 17OHD.

Fluorodeoxyglucose-positron emission tomography as a potential alternative tool for functional diagnosis of glycogen storage disease type I

A 43-year-old woman with genetically confirmed glycogen storage disease type Ib was suspected to have left breast cancer. Fluorodeoxyglucose-positron emission tomography showed high fluorodeoxyglucose accumulation in the whole liver as well as left mammary gland. We consider that high fluorodeoxyglucose accumulation in the liver of patients with glycogen storage disease type I is caused by impaired glucose-6-phosphate metabolism due to the congenital deficiency of glucose-6-phosphatase activities in hepatocytes. This study describes fluorodeoxyglucose-positron emission tomography as a potential alternative tool to diagnose glycogen storage disease type I functionally.

Intracranial germinoma in the lateral ventricle with polydipsia and polyuria: a case report and literature review

Central nervous system germ cell tumors (CNSGCTs) are rare neoplasms which usually develop in the midline structures. They are occasionally involved in off-midline structures of the brain. Here, we report an extremely rare case of an intracranial germinoma in the lateral ventricle. The patient was a 10-year-old boy with a 1-year history of polydipsia and polyuria. Brain magnetic resonance imaging (MRI) showed a relatively homogeneously enhancing lesion in the lateral ventricle, and the posterior pituitary gland was not hyperintense on T1-weighted imaging. Subependymoma was suspected, and tumor removal operation was performed; however, because the intraoperative pathological investigation revealed germinoma, we could only perform partial removal of the tumor. Postoperative histology also confirmed germinoma. Then, the patient received chemotherapy, followed by radiation therapy. MRI showed no recurrence for 6 years after treatment. Intracranial germinoma in the lateral ventricle is extremely rare. The diagnosis is occasionally challenging, especially when the tumors are located in atypical locations. This paper presents a literature review of previously described CNSGCTs of the lateral ventricle to improve awareness of CNSGCTs in atypical locations. We also consider the relationship between imaging findings and clinical manifestations.

Occurrence of voriconazole-induced cutaneous squamous cell carcinoma in Japan: data mining from different national pharmacovigilance databases

Long-term voriconazole use may increase the risk of cutaneous squamous cell carcinoma (cSCC), especially in immunocompromised patients. However, relatively little is known regarding voriconazole-induced cSCC in Japan. Thus, the purpose of this study was to evaluate the association between voriconazole use and cSCC in Japan using different national pharmacovigilance databases. First, using the Japanese Adverse Drug Event Report (JADER) database, we evaluated the association between voriconazole use and cSCC in Japan. Second, using the U. S. Food and Drug Administration Adverse Event Reporting System (FAERS) database, we examined regional differences in the occurrence of voriconazole-induced cSCC between Japan and other countries. We calculated reporting odds ratios (RORs) as disproportionality analysis to evaluate voriconazole-induced cSCC. In this study, cases in which one or more of "Bowen's disease", "Carcinoma in situ of skin", "Keratoacanthoma", "Squamous cell carcinoma in skin", or "Squamous cell carcinoma" were reported as adverse events were considered to be cSCC cases. The analysis based on the JADER database showed an association between voriconazole use and cSCC in Japan, with a ROR (95% confidence interval) of 35.37 (25.60-48.87). Further, the analysis based on the FAERS database revealed that signals were detected in Japan as well as in Western countries and Australia. This study is the first in which the association between voriconazole use and cSCC in Japan is assessed using national pharmacovigilance databases. Healthcare providers need to be fully aware of the potential for cSCC development owing to voriconazole use and in all countries, including Japan, ensure careful follow-up of patients' skin.

POS0841 HIGH-INTENSITY INDUCTION THERAPY COMBINING TOFACITINIB, RITUXIMAB, AND PLASMAPHERESIS IN RAPIDLY PROGRESSIVE INTERSTITIAL LUNG DISEASE ASSOCIATED WITH ANTI-MDA5 ANTIBODY POSITIVE DERMATOMYOSITIS

Background

Rapidly progressive interstitial lung disease (RP-ILD) associated with anti-melanoma differentiation-associated protein 5 (MDA5) autoantibody (Ab) -positive dermatomyositis (DM) is one of the most life-threatening autoimmune conditions. The clinical course is very rapid, leading to death within three months after the onset of symptoms. Although triple therapy which consists of corticosteroids, cyclophosphamide, and tacrolimus has been considered as standard therapy and additional treatments including plasma exchange (PE) and rituximab (RTX) have been reported, the survival rate of patients with poor prognostic factors is still poor even if all of these treatments were applied. Recently, there exist increasing evidences regarding the efficacy of tofacitinib (TOF) in refractory DM. We have treated anti-MDA5Ab-positive RP-ILD with multiple poor prognostic factors with high-intensity induction therapy which combined triple therapy, PE, RTX, and TOF.

Objectives

This study aimed to investigate the therapeutic efficacy of high-intensity induction therapy for patients with anti-MDA5Ab-positive RP-ILD with multiple poor prognostic factors.

Methods

31 patients who were diagnosed with anti-MDA5Ab-positive DM during 2014 to 2021 in our institution were included in this study. The clinical characteristics for poor prognosis were retrospectively analyzed, and the outcomes of high-intensity induction therapy were analyzed for the survival and adverse events.

Results

17 cases were treated before the introduction of TOF. Although triple therapy with RTX, PE, or intravenous immunoglobulin (IVIG) were used, eight out of 10 RP-ILD cases with a ferritin level >400 ng/mL (range, 402.5-5,831; mean, 2,342 ± 2,069) died in median 2.5 months. Poor prognosis was predicted by followings; elevated levels of serum ferritin, lactate dehydrogenase, transaminases, creatinine phosphokinase, and C-reactive protein; decrease in platelets, serum albumin, and oxygen saturation; use of oxygen; higher age; shorter disease duration to admission. The addition of RTX and PE was not enough to control RP-ILD in anti-MDA5Ab positive DM, and prevention of the initial exacerbation of ILD following induction therapy was considered to be important. Based on these observations, high-intensity induction therapy was consisted as follows; triple therapy with decreasing the dose of methylprednisolone by half from 1g to 1 mg/kg, liposteroid to suppress macrophage activity, TOF, PE, and RTX. High-intensity induction therapy was applied in eight patients (ferritin levels; range, 412.2-7,095 ng/mL; mean, 3,558±3,152 ng/mL) with multiple poor prognostic factors described above. Although deaths at two months and eight months due to ILD were observed, significant improvement of survival was documented (Figure 1). Two patients in whom RTX was not initially administered, exacerbation of ILD was observed one month later, which prompted the use of RTX. Several adverse events were observed in high-intensity induction therapy. The most common events were reactivation of cytomegalovirus, meanwhile herpes zoster was not documented. Sustained leukocytopenia and thrombocytopenia were observed in three patients, and two patients developed thrombotic microangiopathy which led to the discontinuation of tacrolimus. Fungal infections in lung were also documented. These adverse events were controllable.

Figure 1.

Conclusion

Significant improvement of survival was observed in patients treated with high-intensity induction therapy. Meanwhile, stratification of patients for poor prognosis would be important.

References

None

Disclosure of Interests

None declared

OP0062 EFFICACY AND SAFETY OF ADALIMUMAB WITH LOW AND HIGH DOSE-METHOTREXATE IN PATIENTS WITH RHEUMATOID ARTHRITIS WITH INADEQUATE RESPONSE TO METHOTREXATE: THE RANDOMISED CONTROLLED MIRACLE STUDY

Background

Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease that causes not only joint pain but also bone destruction resulting in impairment of quality of life. Tumor necrosis factor inhibitors have improved prognosis of patients with rheumatoid arthritis dramatically, especially in combination with methotrexate, however, the optimal dose of the concomitant methotrexate is unclear.

Objectives

To evaluate the efficacy and safety of adalimumab in combination with reduced dose of methotrexate in patients with early RA with inadequate response to methotrexate.

Methods

The MIRACLE study was a multinational, randomized, open-label study in patients with RA with inadequate response to methotrexate conducted in Asia. It compared low dose and high dose methotrexate upon starting adalimumab. Methotrexate-naive patients with RA with a disease duration of less than two years started methotrexate at 6 to 8 mg/week and increased it to the maximum tolerable dose by week 12. Patients who have not achieved remission according to simplified disease activity index (SDAI) despite methotrexate ≥ 10 mg/week at week 24 were randomised to the maximum tolerable dose of methotrexate group (10 to 25 mg/week) or the reduced dose group (6 to 8 mg/week) and started to receive subcutaneous adalimumab 40 mg every other week. The primary endpoint was non-inferiority in the achievement of SDAI remission at week 48 in the reduced dose group compared with the maximum tolerable dose group with a non-inferiority margin of -15% based on two-sided 90% confidence interval. (NCT03505008)

Results

A total of 300 patients were enrolled in the study. Among them, 291 started methotrexate and were included in the analysis. The mean age was 57.7±15.2 years, female was 74.6%, and the mean disease duration from the diagnosis of RA was 21.1±56.2 days. Anti-CCP antibody was positive in 211 (73.0%) and the mean SDAI at study enrollment was 26.5±12.4. At week 24, with the mean dose of methotrexate of 12.6±2.9 mg/week, 108 patients (37.1%) achieved remission according to SDAI and continued MTX monotherapy. 134 patients (46.0%) were randomised and started adalimumab with 68 patients in the maximum tolerable dose group and 66 patients in the reduced dose group. At week 48, the remission achievement rates were 38.4 % and 44.8 %, respectively, with the adjusted risk difference of the reduced dose group to the maximum tolerable dose group of 6.4% (-7.0% to 19.8%, 90% CI), which met the criterion for noninferiority. No significant difference was found in health assessment questionnaire disability index ≤0.5 (59.1% vs 62.0%, respectively, p=0.72) and in radiological remission rates (Δmodified total Sharp score ≤0.5, 66.3% vs 62.0 %, respectively, p=0.59). Adverse drug reactions tended to be more frequent in the maximum tolerable dose group than in the reduced dose group (22.1% vs 9.1%, respectively, p=0.06).

Conclusion

The MIRACLE randomised study demonstrated that, in patients with inadequate response to methotrexate, the efficacy of adalimumab with reduced dose of concomitant methotrexate was not inferior to that with maximum tolerable dose of methotrexate with better safety profile.

Disclosure of Interests

Hiroya Tamai Speakers bureau: Eisai, Grant/research support from: Eisai, Kei Ikeda Speakers bureau: AbbVie, Eisai, Eli Lilly, Novartis, Gilead, Asahi-Kasei, Grant/research support from: Mitsubishi-Tanabe, Toshiaki Miyamoto: None declared, Hiroaki Taguchi: None declared, Chang-Fu Kuo: None declared, Kichul Shin: None declared, Shintaro Hirata Speakers bureau: AbbVie, Asahi-Kasei, Astellas, Ayumi, Bristol Myers Squibb, Celgene, Chugai, Eisai, Eli Lilly, Gilead, Glaxo SmithKline, Janssen, Kyorin, Novartis, Pfizer, Sanofi, Tanabe-Mitsubishi, UCB, Paid instructor for: AbbVie, Mitsubishi-Tanabe, Consultant of: AbbVie, Astellas, Bristol Myers Squibb, Eisai, Gilead, Ily Lilly, Grant/research support from: AbbVie, Asahi-Kasei, Eisai, Otsuka, Sanofi, Shionogi, Chugai, Pfizer, Tanabe-Mitsubishi, Eli Lilly, UCB, yutaka okano: None declared, Shinji Sato Speakers bureau: AbbVie, Eisai, Grant/research support from: AbbVie, Eisai, Hidekata Yasuoka Speakers bureau: AbbVie, Asahi Kasei Pharma, Astellas, Daiichi-Sankyo, Eisai, Kissei, Takeda, Mitsubishi-Tanabe, Chugai, Novartis, Eli Lilly, Pfizer, Janssen, Sanofi, Teijin, Boehringer-Ingelheim, Bayer, Glaxo Smith Kline, Paid instructor for: AbbVie, Consultant of: AbbVie, Asahi Kasei, Grant/research support from: Mitsubishi-Tanabe, Takeda, Daiichi-Sankyo, Chugai, Bristol-Myers, MSD, Astellas, In Ah Choi Speakers bureau: Abbvie, Eisai, Sung-Hwan Park: None declared, Meng-Yu Weng Paid instructor for: Novartis, Eli Lilly, ChuGai, Abbvie, Consultant of: Abbvie, Masataka Kuwana Speakers bureau: Astellas, Asahi Kasei Pharma, Boehringer-Ingelheim, Chugai, Eisai, Janssen, Mochida, Nippon Shinyaku, Ono Pharmaceuticals, Pfizer, Mitsubishi-Tanabe, Consultant of: Boehringer-Ingelheim, Kissei, Mochida, Grant/research support from: AbbVie, Asahi Kasei Pharma, Boehringer-Ingelheim, Chugai, Eisai, MBL, Nippon Shinyaku, Ono Pharmaceuticals, Mitsubishi-Tanabe, Yun Jong Lee Grant/research support from: Yuhan, Tomonori Ishii Speakers bureau: Chugai, Mitsubishi-Tanabe, Glaxo Smith Kline, Pfizer, Eli Lilly, Janssen, AbbVie, Eisai, Astellas, Jinhyun Kim: None declared, Hideto Kameda Speakers bureau: AbbVie, Pfizer, Consultant of: AbbVie, Grant/research support from: AbbVie, Eisai, Toshihisa Kojima Speakers bureau: AbbVie, Pfizer, Eisai, Grant/research support from: AbbVie, Han Joo Baek: None declared, Ping-Ning Hsu: None declared, Chun-Ming Huang Paid instructor for: Abbvie, Pfizer, Tien-Tsai Cheng Paid instructor for: Abbvie, Grant/research support from: Abbvie, Wan-Yu Sung: None declared, Takehiro Taninaga Shareholder of: Eisai.co.,Ltd., Employee of: Eisai.co.,Ltd., Masahiko Mori Shareholder of: Eisai.co.,Ltd., Employee of: Eisai.co.,Ltd., Hideaki Miyagishi Shareholder of: Eisai.co.,Ltd., Employee of: Eisai.co.,Ltd., Yasunori Sato Speakers bureau: Eisai Co., Ltd. Kowa Company, Ltd., Consultant of: MOCHIDA PHARMACEUTICAL CO., LTD, Tsutomu Takeuchi Speakers bureau: Astellas, AbbVie, Ayumi, Bristol Myers Squibb, Chugai, Daiichi-Sankyo, Eisai, Eli Lilly, Gilead, Glaxo Smith Kline, Janssen, Mitsubishi-Tanabe, Nippon-kayaku, Novartis, Pfizer, Sanofi, UCB, Grant/research support from: Asahi Kasei, AbbVie, Ayumi, Boehringer-Ingelheim, Chugai, Eisai, Eli Lilly, Mitsubishi-Tanabe, Sanofi, UCB, Yuko Kaneko Speakers bureau: Asahi Kasei, Astellas, Ayumi, Bristol Myers Squibb, Chugai, Eisai, Elli Lilly, Mitsubishi-Tanabe, Novartis, UCB, Grant/research support from: AbbVie, Chugai, Eisai, Mitsubishi-Tanabe, UCB.

Mechanical loading of intraluminal pressure mediates wound angiogenesis by regulating the TOCA family of F-BAR proteins

Angiogenesis is regulated in coordinated fashion by chemical and mechanical cues acting on endothelial cells (ECs). However, the mechanobiological mechanisms of angiogenesis remain unknown. Herein, we demonstrate a crucial role of blood flow-driven intraluminal pressure (IP) in regulating wound angiogenesis. During wound angiogenesis, blood flow-driven IP loading inhibits elongation of injured blood vessels located at sites upstream from blood flow, while downstream injured vessels actively elongate. In downstream injured vessels, F-BAR proteins, TOCA1 and CIP4, localize at leading edge of ECs to promote N-WASP-dependent Arp2/3 complex-mediated actin polymerization and front-rear polarization for vessel elongation. In contrast, IP loading expands upstream injured vessels and stretches ECs, preventing leading edge localization of TOCA1 and CIP4 to inhibit directed EC migration and vessel elongation. These data indicate that the TOCA family of F-BAR proteins are key actin regulatory proteins required for directed EC migration and sense mechanical cell stretching to regulate wound angiogenesis.

Chemical and mechanical cues coordinately regulate angiogenesis. Here, the authors show that blood flow-driven intraluminal pressure regulates wound angiogenesis. Findings indicate that TOCA family of F-BAR proteins act as actin regulators required for endothelial cell migration and sense mechanical cell stretching to regulate wound angiogenesis.

GWAS of thyroid dysgenesis identifies a risk locus at 2q33.3 linked to regulation of Wnt signaling

Congenital hypothyroidism due to thyroid dysgenesis (TD), presented as thyroid aplasia, hypoplasia or ectopia, is one of the most prevalent rare diseases with an isolated organ malformation. The pathogenesis of TD is largely unknown, although a genetic predisposition has been suggested. We performed a genome-wide association study (GWAS) with 142 Japanese TD cases and 8380 controls, and found a significant locus at 2q33.3 (top SNP, rs9789446: P = 4.4 × 10-12), which was replicated in a German patient cohort (P = 0.0056). A subgroup analysis showed that rs9789446 confers a risk for thyroid aplasia (per allele odds ratio = 3.17) and ectopia (3.12) but not for hypoplasia. Comprehensive epigenomic characterization of the 72-kb disease-associated region revealed that it was enriched for active enhancer signatures in human thyroid. Analysis of chromosome conformation capture data showed long-range chromatin interactions of this region with promoters of two genes, FZD5 and CCNYL, mediating Wnt signaling. Moreover, the finding that rs9789446 is a thyroid-specific expression quantitative trait loci, adding further evidence for a cis-regulatory function of this region in thyroid tissue. Specifically, because the risk rs9789446 allele is associated with increased thyroidal expression of FDZ5 and CCNYL1 and given the recent demonstration of perturbed early thyroid development following over-activation of Wnt signaling in zebrafish embryos, an enhanced Wnt signaling in risk allele carriers provide a biologically plausible TD mechanism. In conclusion, our work found the first risk locus for TD, exemplifying that in rare diseases with relatively low biological complexity, GWAS may provide mechanistic insights even with a small sample size.

Blood Flow Regulates Glomerular Capillary Formation in Zebrafish Pronephros

BACKGROUND

The renal glomerulus is a tuft of capillaries in Bowman's capsule and functions as a blood-filtration unit in the kidney. The unique glomerular capillary tuft structure is relatively conserved through vertebrate species. However, the morphogenetic mechanism governing glomerular capillary tuft formation remains elusive.

METHODS

To clarify how glomerular capillaries develop, we analyzed glomerular capillary formation in the zebrafish pronephros by exploiting fluorescence-based bio-imaging technology.

RESULTS

During glomerular capillary formation in the zebrafish pronephros, endothelial cells initially sprouted from the dorsal aorta and formed the capillaries surrounding the bilateral glomerular primordia in response to podocyte progenitor-derived vascular endothelial growth factor-A. After formation, blood flow immediately occurred in the glomerular primordia-associated capillaries, while in the absence of blood flow, they were transformed into sheet-like structures enveloping the glomerular primordia. Subsequently, blood flow induced formation of Bowman's space at the lateral sides of the bilateral glomerular primordia. Concomitantly, podocyte progenitors enveloped their surrounding capillaries while moving toward and coalescing at the midline. These capillaries then underwent extensive expansion and remodeling to establish a functional glomerular capillary tuft. However, stopping blood flow inhibited the remodeling of bilateral glomerular primordia, which therefore remained unvascularized but covered by the vascular sheets.

CONCLUSIONS

We delineated the morphogenetic processes governing glomerular capillary tuft formation in the zebrafish pronephros and demonstrated crucial roles of blood flow in its formation. Blood flow maintains tubular structures of the capillaries surrounding the glomerular primordia and promotes glomerular incorporation of these vessels by inducing the remodeling of glomerular primordia.