Successful Treatment of Lithium-Induced Nephrogenic Diabetes Insipidus with Celecoxib: A Promising Therapeutic Option.

BACKGROUND Nephrogenic diabetic insipidus (NDI) poses a challenge in clinical management, particularly when associated with lithium ingestion. Non-selective non-steroidal anti-inflammatory drugs (NSAIDs) have been widely used for the treatment of numerous diseases worldwide, including NDI. However, many studies have reported the diverse adverse effects of long-term use of non-selective NSAIDs. Celecoxib, a selective cyclooxygenase-2 (COX-2) inhibitor, is a better drug to relieve pain and inflammation in terms of long-term safety and efficacy than non-selective NSAIDs. Nevertheless, there are few reports describing the effectiveness of celecoxib in treating NDI. CASE REPORT We report a case of a 46-year-old woman with schizophrenia who presented with severe hypernatremia and refractory polyuria due to lithium-induced NDI. Cessation of lithium ingestion and traditional treatments, including trichlormethiazide and desmopressin, yielded minimal improvement in her hypernatremia and polyuria. Her sodium level needed to be strictly controlled with the infusion of dextrose 5% in water. Given the safety of celecoxib, we decided to initiate celecoxib as the treatment of lithium-induced NDI instead of indomethacin. Notably, the introduction of celecoxib led to a substantial and sustained amelioration of polyuria and hypernatremia without any celecoxib-associated adverse effects. Even after transfer to another hospital, stability in serum sodium levels persisted with celecoxib. CONCLUSIONS We presented a case of lithium-induced NDI successfully treated with celecoxib, a selective COX-2 inhibitor. To the best of our knowledge, this is the first reported case of successful treatment of lithium-induced NDI with celecoxib, and suggests celecoxib is a viable therapeutic option warranting further exploration. Physicians should consider its use when faced with the challenging management of lithium-induced NDI.

A Case Report of Diabetes in a Patient with Glycogen Storage Disease Type 1a.

Glycogen storage disease type 1a (GSD-1a) is a rare congenital disease. Recently, life expectancy with GSD-1a has been improved by its early diagnosis and management. Complications of diabetes with GSD-1a are extremely rare. The optimal treatment for glucose control using this disease combination remains unclear. The existence of GSD-1a and diabetes can cause both hypoglycemia and hyperglycemia, making glucose control especially problematic. In the present report, α-glucosidase inhibitor (α-GI) and dipeptidyl peptidase-4 (DPP-4) inhibitors improved hyperglycemia without symptoms of hypoglycemia in a patient with diabetes and GSD-1a using intermittent continuous glucose monitoring (isCGM).

Prediction-based prompt levothyroxine replacement to prevent a hypothyroid state after immune-related adverse events involving the thyroid gland.

Immune checkpoint inhibitors (ICIs) are used for various malignancies, although they frequently cause immune-related adverse events involving the thyroid gland (thyroid irAEs). We conducted a retrospective cohort study to elucidate thyroid function outcomes. Fifty of 639 patients who received PD-1 blockade therapy met criteria and were divided into the following groups: thyrotoxicosis with subsequent hypothyroidism (Toxic-Hypo, n = 21); thyrotoxicosis without subsequent hypothyroidism (Toxic, n = 9); and hypothyroidism without prior thyrotoxicosis (Hypo, n = 20). The Toxic-Hypo group developed thyroid irAEs earlier than the Toxic group (26 vs. 91 days; p < 0.001), and had higher serum free T4 levels (3.210 vs. 1.880 ng/dL; p = 0.011). In addition, positive anti-thyroglobulin antibodies (TgAbs) at thyroid irAE onset were more common in the Toxic-Hypo group (93.3%) than in the Toxic group (0.0%; p = 0.005) and Hypo group (44.4%; p = 0.007). The Toxic-Hypo group developed severe hypothyroidism and required larger levothyroxine (LT4) doses than the Hypo group (75 vs. 25 µg/day; p = 0.007). We predicted that patients with positive TgAbs who developed severe thyrotoxicosis within 4 weeks after the first ICI administration would develop subsequent hypothyroidism. We treated 4 such patients with prompt LT4 replacement, characterized by LT4 initiation after thyrotoxicosis improvement and quick dose titration. Their euthyroid state was successfully maintained, in contrast with patients receiving conventional replacement. In conclusion, rapid-onset severe thyrotoxicosis in patients with TgAbs correlated with a high likelihood of subsequent hypothyroidism. Accordingly, prompt LT4 replacement is suggested to prevent a severely hypothyroid state.

Delayed-onset immune-related adverse events involving the thyroid gland by immune checkpoint inhibitors in combination with chemotherapy: a case report and retrospective cohort study.

Immune checkpoint inhibitors (ICIs) frequently cause immune-related adverse events (irAEs) that often involve endocrine organs. Pembrolizumab and atezolizumab are currently administered in combination with chemotherapy for several malignancies. Although transient thyrotoxicosis within 6 weeks after the first ICI dose is the typical course of thyroid irAEs with ICI monotherapy, we encountered a unique course of a thyroid irAE in a patient who received combination therapy consisting of pembrolizumab plus pemetrexed and carboplatin. Delayed onset of thyrotoxicosis occurred at 22 weeks after the first dose of pembrolizumab. To understand more about this curious event, we conducted a retrospective cohort study of the following groups: pembrolizumab monotherapy (Pem-mono), pembrolizumab plus chemotherapy (Pem-combi), atezolizumab monotherapy (Atezo-mono), and atezolizumab plus chemotherapy (Atezo-combi). There were no differences in the incidence of overt thyroid irAEs: Pem-mono, 12 of 151 patients (7.9%) versus Pem-combi, 4 of 56 patients (7.1%) (p = 0.85) and Atezo-mono, 5 of 27 patients (18.5%) versus Atezo-combi, 5 of 57 patients (8.8%) (p = 0.20). Through detailed analyses of patients with thyrotoxicosis, we found some patients with delayed-onset thyroid irAE, defined as development at 16 weeks or more after the first ICI dose. Delayed-onset thyroid irAEs were only observed in the combination therapy groups: Pem-combi or Atezo-combi, 3 of 8 patients versus Pem-mono or Atezo-mono, 0 of 10 patients. Our observation that thyroid irAE development can be delayed with ICIs when used in combination with chemotherapy suggests longer monitoring of thyroid function is needed to avoid missing irAEs.

Circulatory C-type natriuretic peptide reduces mucopolysaccharidosis-associated craniofacial hypoplasia in vivo.

Skeletal alterations in the head and neck region, such as midfacial hypoplasia, foramen magnum stenosis and spinal canal stenosis, are commonly observed in patients with mucopolysaccharidosis (MPS). However, enzyme replacement therapy (ERT), one of the major treatment approaches for MPS, shows limited efficacy for skeletal conditions. In this study, we analysed the craniofacial morphology of mice with MPS type VII, and investigated the underlying mechanisms promoting jaw deformities in these animals. Furthermore, we investigated the effects of C-type natriuretic peptide (CNP), a potent endochondral ossification promoter, on growth impairment of the craniofacial region in MPS VII mice when administered alone or in combination with ERT. MPS VII mice exhibited midfacial hypoplasia caused by impaired endochondral ossification, and histological analysis revealed increased number of swelling cells in the resting zone of the spheno-occipital synchondrosis (SOS), an important growth centre for craniomaxillofacial skeletogenesis. We crossed MPS VII mice with transgenic mice in which CNP was expressed in the liver under the control of the human serum amyloid-P component promoter, resulting in elevated levels of circulatory CNP. The maxillofacial morphological abnormalities associated with MPS VII were ameliorated by CNP expression, and further prevented by a combination of CNP and ERT. Histological analysis showed that ERT decreased the swelling cell number, and CNP treatment increased the width of the proliferative and hypertrophic zones of the SOS. Furthermore, the foramen magnum and spinal stenoses observed in MPS VII mice were significantly alleviated by CNP and ERT combination. These results demonstrate the therapeutic potential of CNP, which can be used to enhance ERT outcome for MPS VII-associated head and neck abnormalities.

High-throughput Screening in Combination With a Cohort Study for Iodothyronine Deiodinases.

Regulatory mechanisms of iodothyronine deiodinases (DIOs) require further elucidation, and conventional methods for evaluating DIOs are unsuitable for high-throughput screening (HTS). Here we explored factors of transcriptional regulation of 3 types of DIOs (DIO1, DIO2, and DIO3) from a chemical library using our designed HTS. We constructed HTS based on a promoter assay and performed a screen of 2480 bioactive compounds. For compounds that were clinically approved, we validated hit compounds through a retrospective cohort study in our department that evaluated changes in thyroid function in patients using the compounds as drug therapy. Furthermore, we verified the involvement of DIOs using mice treated with the compounds. Of the hit compounds, 6 and 7 compounds transcriptionally up- and downregulated DIO1, respectively; 34 transcriptionally upregulated DIO2; and 5 and 2 compounds transcriptionally up- and downregulated DIO3, respectively. The cohort study clarified the clinical effects of some hit compounds: ritodrine increased free triiodothyronine (fT3)/free thyroxine (fT4) ratio and decreased serum thyroid-stimulating hormone (TSH) levels, tadalafil increased serum fT3 levels, and tyrosine kinase inhibitors (TKIs) decreased serum fT3 and fT4 levels and increased serum TSH levels. Following in vivo experiments using treated mice, consistent results were observed in ritodrine, which upregulated DIO2 in the thyroid gland. In conclusion, we completed HTS for DIOs and obtained attractive hit compounds. Our cohort study revealed the clinical significance of ritodrine, sildenafil, and TKIs. We hope our unique method will contribute to analyzing various targets and lists of hit compounds will promote understanding of DIOs.

Molecular Mechanism of Induction of Bone Growth by the C-Type Natriuretic Peptide.

The skeletal development process in the body occurs through sequential cellular and molecular processes called endochondral ossification. Endochondral ossification occurs in the growth plate where chondrocytes differentiate from resting, proliferative, hypertrophic to calcified zones. Natriuretic peptides (NPTs) are peptide hormones with multiple functions, including regulation of blood pressure, water-mineral balance, and many metabolic processes. NPTs secreted from the heart activate different tissues and organs, working in a paracrine or autocrine manner. One of the natriuretic peptides, C-type natriuretic peptide-, induces bone growth through several mechanisms. This review will summarize the knowledge, including the newest discoveries, of the mechanism of CNP activation in bone growth.

Effect of C-type natriuretic peptide on craniofacial skeletogenesis in mice during the pubertal growth spurt.

OBJECTIVE: This study aimed to determine the effect of C-type natriuretic peptide (CNP) overexpression on craniofacial growth during the pubertal growth period in mice. DESIGN: Six-week-old C57BL/6 mice were injected with pLIVE-Empty vectors (Control mice) and pLIVE-NPPC vectors (CNP mice) using the hydrodynamic method. Morphological analyses were performed at the age of 12 weeks. RESULTS: Micro-computed tomography (µCT) images showed significant (p < 0.05) hyperplasia in the maxilla along the sagittal plane (CNP mice: 13.754 mm, Control mice: 13.215 mm). Further, the images revealed significant bone overgrowth in the sagittal direction in the sphenoid (CNP mice: 6.936 mm, Control mice: 6.411 mm) and occipital (CNP mice: 4.051 mm, Control mice: 3.784 mm) bones in the CNP mice compared with that in the Control mice. Compared with SAP-Nppc-Tg mice in previous studies, although there was no effect on nose length and nasal bone length, the effect was sufficient to improve craniofacial hypogrowth. Furthermore, CNP promoted sagittal cranial growth by increasing the thickness of the spheno-occipital synchondrosis in organ cultures and nasal septal cartilage in micromass cultures, which were derived from 6-week-old mice. CONCLUSIONS: We have previously shown that the elevated blood levels of CNP from the neonatal period affect midfacial skeletogenesis by promoting endochondral ossification using mice (SAP-Nppc-Tg mice). The overexpression of CNP, even in 6-weeks-old mice, promoted growth in the sagittal direction within the maxillary region. These findings indicate the therapeutic potential of CNP for the treatment of midfacial hypoplasia during the pubertal growth spurt.

Thyroid hormone economy in mice overexpressing iodothyronine deiodinases.

In peripheral tissues, triiodothyronine (T3) production and consequent thyroid hormone actions are mainly regulated by iodothyronine deiodinases (DIOs) classified into 3 types: D1, D2, and D3. We aimed to investigate the effects of peripheral DIOs on thyroid hormone economy independent of the hypothalamus-pituitary-thyroid axis. We cloned coding sequences of human DIOs with FLAG-tag and HiBiT-tag sequences into a pcDNA3.1 vector. To obtain full-length proteins, we modified these vectors by cloning the selenocysteine insertion sequence of each DIO (SECIS vectors). Western blot analyses and HiBiT lytic assay using HEK293T cells revealed that SECIS vectors expressed full-length proteins with substantial activity. Subsequently, in vivo transfections of pLIVE-based SECIS vectors into male C57BL/6J mice were performed by hydrodynamic gene delivery to generate mice overexpressing DIOs predominantly in the liver (D1, D2, and D3 mice). After 7 days from transfections, mice were analyzed to clarify phenotypes. To summarize, serum thyroid hormone levels did not change in D1 mice but D2 mice had higher serum free T3 levels. D3 mice developed hypothyroidism with higher serum reverse T3 (rT3) levels. Transfections with levothyroxine administration suggested that thyroid hormone action was upregulated in D2 mice. Our DIO-overexpressing mice provided insights on the physiological properties of upregulated DIOs: D2 augments local thyroid hormone action and recruits T3 into the circulation: D3 decreases circulating T3 and T4 levels with elevated rT3, leading to consumptive hypothyroidism. As D3 mice are expected to be a novel hypothyroidism model, they can contribute to progress in the field of thyroid hormone economy and action.

Bezafibrate induces hypothyroidism in a patient with resistance to thyroid hormone ß due to a G347R variant.

OBJECTIVE: A unique clinical course was observed in a patient with resistance to thyroid hormone ß (RTHß) caused by a variant of the THRB gene leading to the replacement of glycine with arginine in codon 347 (p.G347R). He presented with the syndrome of inappropriate secretion of thyrotropin (TSH) (free T4 [fT4]: 32.43 pmol/L, TSH: 4.67 mIU/L), but slowly developed progressive hypothyroidism (fT4: 8.37 pmol/L, TSH: 100.90 mIU/L) that resolved after suspending bezafibrate (BZ) treatment (fT4: 32.18 pmol/L, TSH: 7.14 mIU/L). This study clinically and experimentally evaluated this interesting phenomenon. METHODS: A retrospective cohort analysis of non-RTHß patients was performed at Kyoto University Hospital. Data before BZ treatment were compared to the first data after treatment. Using reporter assays of iodothyronine deiodinases (DIO1, DIO2, DIO3) in HEK293T cells, we performed functional analyses of mutant thyroid hormone receptor ß with p.G347R (G347R TRß). Mice with G347R TRß were generated by hydrodynamic gene delivery. RESULTS: In non-RTHß patients (n = 7), BZ treatment did not change serum free T3 and TSH but significantly increased fT4 (p = .008). BZ administration increased DIO3 reporter activity in the context of G347R TRß, whereas did not change DIO1 and DIO2 reporter activity. In the livers of mice with G347R TRß, BZ administration increased reverse T3 content, which corresponded to an increase in Dio3 messenger RNA. CONCLUSIONS: While hypothyroidism associated with BZ treatment did not occur in non-RTHß patients, it was observed in a patient with RTHß due to the p.G347R variant. Liver DIO3 upregulation might involve this hypothyroidism.

Opioid-induced adrenal insufficiency in transdermal fentanyl treatment: a revisited diagnosis in clinical setting.

Opioids are widely used for treatment of acute and chronic pain. However, opioids have several well-known clinical adverse effects such as constipation, nausea, respiratory depression and drowsiness. Endocrine dysfunctions are also opioid-induced adverse effects but remain under-diagnosed in clinical settings, especially opioid-induced adrenal insufficiency (OIAI). A 46-year-old woman was treated with transdermal fentanyl at a dose of 90-120 mg daily morphine milligram equivalent for non-malignant chronic pain for four years. Fatigue, loss of appetite and decrease in vitality began about two years after starting fentanyl. Subsequently, constipation and abdominal pain appeared and became worse, which led to suspicion of adrenal insufficiency. Clinical diagnosis of OIAI was established based on laboratory findings of secondary adrenal insufficiency, including corticotropin-releasing hormone stimulation test, clinical history of long-term fentanyl use, and exclusion of other hypothalamic-pituitary diseases. Oral corticosteroid replacement therapy was unable to relieve her abdominal pain and constipation; opioid-rotation and dose-reduction of fentanyl were not feasible because of her persistent pain and severe anxiety. While her clinical course clearly suggested that long-term, relatively high-dose transdermal fentanyl treatment may have contributed to the development of secondary adrenal insufficiency, the symptoms associated with OIAI are generally non-specific and complex. Together with under-recognition of OIAI as a clinical entity, the non-specific, wide range of symptoms can impede prompt diagnosis. Thus, vigilance for early symptoms enabling treatments including corticosteroid replacement therapy is necessary for patients taking long-term and/or high dose opioid treatment.

Clinical features and thyroid dysfunction in adverse events involving the pituitary gland during PD-1 blockade therapy.

OBJECTIVE: Programmed cell death-1 (PD-1) blockade therapy, an immune checkpoint treatment, can induce hypophysitis or hypopituitarism as an immune-related adverse event (pituitary irAE). We aimed to clarify the clinical features of pituitary irAEs during PD-1 blockade therapy. DESIGN, PATIENTS AND MEASUREMENTS: This retrospective study investigated consecutive patients treated with nivolumab, an anti-PD-1 antibody, at Kyoto University Hospital between 1 September 2014 and 31 August 2019. We examined patients' baseline characteristics and analysed the clinical data of those who developed pituitary irAEs. RESULTS: Of the 374 recruited patients, 7 (1.9%) developed pituitary irAEs, and each presented with isolated secondary adrenal insufficiency. In 4 patients, changes in ACTH were delayed relative to those in cortisol: when serum cortisol levels fell below the reference range, plasma ACTH levels were still normal. Pituitary irAEs were accompanied by elevated serum-free T3 (fT3) levels, which resolved with glucocorticoid replacement. Serum TSH levels were not suppressed despite elevated serum fT3 levels and 1 patient even presented with high fT3 level above the reference range (fT3, 7.1 pmol/L; free T4 (fT4), 13.9 pmol/L; and TSH, 5.1 mIU/L). CONCLUSIONS: Isolated secondary adrenal insufficiency was a common pituitary irAE during PD-1 blockade therapy. This condition was accompanied by thyroid dysfunction, including elevation of fT3 without TSH suppression.

Is C-type natriuretic peptide regulated by a feedback loop? A study on systemic and local autoregulatory effect.

C-type natriuretic peptide (CNP) is a pivotal enhancer of endochondral bone growth and is expected to be a therapeutic reagent for impaired skeletal growth. Although we showed that CNP stimulates bone growth as a local regulator in the growth plate via the autocrine/paracrine system, CNP is abundantly produced in other various tissues and its blood concentration is reported to correlate positively with growth velocity. Therefore we investigated the systemic regulation of CNP levels using rodent models. In order to examine whether CNP undergoes systemic feedback regulation, we investigated blood CNP levels and local CNP expression in various tissues, including cartilage, of 4-week-old rats after systemic administration of sufficient amounts of exogenous CNP (0.5 mg/kg/day) for 3 days. This CNP administration did not alter blood NT-proCNP levels in male rats but decreased mRNA expression only in tissue that included cartilage. Decrease in expression and blood NT-proCNP were greater in female rats. To analyze the existence of direct autoregulation of CNP in the periphery as an autocrine/paracrine system, we estimated the effect of exogenous supplementation of CNP on the expression of endogenous CNP itself in the growth plate cartilage of extracted fetal murine tibias and in ATDC5, a chondrogenic cell line. We found no alteration of endogenous CNP expression after incubation with adequate concentrations of exogenous CNP for 4 and 24 hours, which were chosen to observe primary and later transcriptional effects, respectively. These results indicate that CNP is not directly autoregulated but indirectly autoregulated in cartilage tissue. A feedback system is crucial for homeostatic regulation and further studies are needed to elucidate the regulatory system of CNP production and function.

C-Type Natriuretic Peptide Restores Growth Impairment Under Enzyme Replacement in Mice With Mucopolysaccharidosis VII.

Growth impairment in mucopolysaccharidoses (MPSs) is an unresolved issue as it is resistant to enzyme replacement therapy (ERT) and growth hormone therapy. C-type natriuretic peptide (CNP) is a promising agent that has growth-promoting effects. Here we investigate the effects of CNP on growth impairment of MPSs using Gusbmps-2J mice, a model for MPS type VII, with combination therapy of CNP and ERT by hydrodynamic gene delivery. Although monotherapies were not sufficient to restore short statures of treated mice, combination therapy resulted in successful restoration. The synergistic effects of CNP and ERT were not only observed in skeletal growth but also in growth plates. ERT reduced cell swelling in the resting zone and increased cell number by accelerating proliferation or inhibiting apoptosis. CNP thickened the proliferative and hypertrophic zones. Regarding changes in the bone, ERT restored bone sclerosis through decreased bone formation and increased bone resorption, and CNP did not adversely affect this process. In addition, improvement of joint deformation by ERT was suggested by analyses of joint spaces and articular cartilage. CNP additively provided restoration of the short stature of MPS VII mice in combination with ERT, which improved abnormalities of growth plates and bone metabolism.

Evaluation of image quality of pituitary dynamic contrast-enhanced MRI using time-resolved angiography with interleaved stochastic trajectories (TWIST) and iterative reconstruction TWIST (IT-TWIST).

BACKGROUND: Time-resolved angiography with interleaved stochastic trajectories (TWIST) is a keyhole imaging with frequent sampling of central k-space data and view-sharing for the peripheral k-space of dynamic phases. IT-TWIST is a technique to reconstruct images with a smaller temporal footprint using the same raw data obtained with TWIST by iterative reconstruction. PURPOSE: To compare image quality between TWIST and IT-TWIST in 3D pituitary DCE-MRI. STUDY TYPE: Retrospective observation study. POPULATION: Fifty-one patients (23 men, 28 women) who underwent 3D pituitary DCE-MRI using TWIST between July 2016 and April 2017. FIELD STRENGTH/SEQUENCE: 3T/TWIST and IT-TWIST. ASSESSMENT: Visual evaluation was conducted for image quality of delineation of the pituitary stalk and posterior lobe during the early arterial phase, cerebral white matter near the sella turcica, and the mass lesion. Bolus sharpness of the pituitary stalk, posterior lobe, and bilateral cavernous sinus was evaluated on the enhancement slope map calculated from TWIST and IT-TWIST. Temporal stability of intensity of the nonenhanced area was evaluated on temporal standard deviation (SD) maps calculated from TWIST and IT-TWIST. STATISTICAL TESTS: Paired t-test or Wilcoxon rank-sum test was used to test the differences between TWIST and IT-TWIST in both visual evaluation and region of interest evaluation. RESULTS: Scores of visual evaluations for IT-TWIST were significantly better than those for TWIST (P < 0.001) in all items. Enhancement slope for IT-TWIST was significantly higher than that for TWIST in posterior lobe, and right and left cavernous sinus (P < 0.001). Temporal SD for IT-TWIST was significantly lower than that for TWIST in all items, with statistical significance (P < 0.001). DATA CONCLUSION: IT-TWIST yielded better visualization, and better enhancement slope, and less temporal SD compared with TWIST in 3D pituitary DCE-MRI. Evidence Level: 4 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2020;51:1497-1506.

Exogenous C-type natriuretic peptide therapy for impaired skeletal growth in a murine model of glucocorticoid treatment.

Growth retardation is an important side effect of glucocorticoid (GC)-based drugs, which are widely used in various preparations to treat many pediatric diseases. We investigated the therapeutic effect of exogenous CNP-53, a stable molecular form of intrinsic CNP, on a mouse model of GC-induced growth retardation. We found that CNP-53 successfully restored GC-induced growth retardation when both dexamethasone (DEX) and CNP-53 were injected from 4 to 8 weeks old. Notably, CNP-53 was not effective during the first week. From 4 to 5 weeks old, neither CNP-53 in advance of DEX, nor high-dose CNP-53 improved the effect of CNP. Conversely, when CNP-53 was started at 5 weeks old, final body length at 8 weeks old was comparable to that when CNP-53 was started at 4 weeks old. As for the mechanism of resistance to the CNP effect, DEX did not impair the production of cGMP induced by CNP. CNP reduced Erk phosphorylation even under treatment with DEX, while CNP did not changed that of p38 or GSK3ß. Collectively, the effect of CNP-53 on GC-induced growth retardation is dependent on age in a mouse model, suggesting adequate and deliberate use of CNP would be effective for GC-induced growth retardation in clinical settings.

Foramen magnum stenosis and midface hypoplasia in C-type natriuretic peptide-deficient rats and restoration by the administration of human C-type natriuretic peptide with 53 amino acids.

C-type natriuretic peptide (CNP)-knockout (KO) rats exhibit impaired skeletal growth, with long bones shorter than those in wild-type (WT) rats. This study compared craniofacial morphology in the CNP-KO rat with that in the Spontaneous Dwarf Rat (SDR), a growth hormone (GH)-deficient model. The effects of subcutaneous administration of human CNP with 53 amino acids (CNP-53) from 5 weeks of age for 4 weeks on craniofacial morphology in CNP-KO rats were also investigated. Skulls of CNP-KO rats at 9 weeks of age were longitudinally shorter and the foramen magnum was smaller than WT rats. There were no differences in foramen magnum stenosis and midface hypoplasia between CNP-KO rats at 9 and 33 weeks of age. These morphological features were the same as those observed in CNP-KO mice and activated fibroblast growth factor receptor 3 achondroplasia-phenotype mice. In contrast, SDR did not exhibit foramen magnum stenosis and midface hypoplasia, despite shorter stature than in control rats. After administration of exogenous CNP-53, the longitudinal skull length and foramen magnum size in CNP-KO rats were significantly greater, and full or partial rescue was confirmed. The synchondrosis at the cranial base in CNP-KO rats is closed at 9 weeks, but not at 4 weeks of age. In contrast, synchondrosis closure in CNP-KO rats treated with CNP-53 was incomplete at 9 weeks of age. Administration of exogenous CNP-53 accelerated craniofacial skeletogenesis, leading to improvement in craniofacial morphology. As these findings in CNP-KO rats are similar to those in patients with achondroplasia, treatment with CNP-53 or a CNP analog may be able to restore craniofacial morphology and foramen magnum size as well as short stature.

Incidence, features, and prognosis of immune-related adverse events involving the thyroid gland induced by nivolumab.

BACKGROUND: Blocking the PD-1 pathway induces immune-related adverse events (irAEs) which often involve the thyroid gland (thyroid irAEs). Clinical features of a thyroid irAE including its predictability and relationship to prognosis remain to be elucidated. METHODS: Two hundred consecutive patients treated with nivolumab at Kyoto University Hospital between September 1, 2014 and August 31, 2017 were included in a retrospective cohort study. We systematically determined and classified subclinical and overt thyroid irAEs based on data collected of serum free T4 and TSH levels. Baseline characteristics and detailed clinical data were analyzed, and analyses of overall survival (OS) excluded patients censored within 1 month from the first administration of nivolumab. RESULTS: Sixty-seven patients (33.5%) developed thyroid irAEs and these were divided into a subclinical thyroid irAE group (n = 40, 20.0%) and an overt thyroid irAE group (n = 27, 13.5%). Patients with thyroid uptake of FDG-PET before treatment showed high incidences of overt thyroid irAE (adjusted odds ratio 14.48; 95% confidence interval [CI] 3.12-67.19), while the same relationship was not seen with subclinical thyroid irAE. Regarding the total cohort, the thyroid irAE (+) group had a significantly longer median OS than the thyroid irAE (-) group (16.1 versus 13.6 months, hazard ratio [HR] 0.61; 95% CI 0.39-0.93). In 112 non-excluded patients with lung cancer, the thyroid irAE (+) group similarly had a longer median OS than the thyroid irAE (-) group (not reached versus 14.2 months, HR 0.51; 95% CI 0.27-0.92). However, this observation was not seen in 41 non-excluded patients with malignant melanoma (12.0 versus 18.3 months, HR 1.54; 95% CI 0.67-3.43). CONCLUSIONS: By thyroid uptake of FDG-PET, overt thyroid irAEs could be predicted before nivolumab therapy. Thyroid irAEs related to good prognosis in lung cancer but might be inconclusive in malignant melanoma.

Exogenous C-type natriuretic peptide restores normal growth and prevents early growth plate closure in its deficient rats.

Signaling by C-type natriuretic peptide (CNP) and its receptor, natriuretic peptide receptor-B, is a pivotal stimulator of endochondral bone growth. We recently developed CNP knockout (KO) rats that exhibit impaired skeletal growth with early growth plate closure. In the current study, we further characterized the phenotype and growth plate morphology in CNP-KO rats, and the effects of exogenous CNP in rats. We used CNP-53, an endogenous form of CNP consisting of 53 amino acids, and administered it for four weeks by continuous subcutaneous infusion at 0.15 or 0.5 mg/kg/day to four-week old CNP-KO and littermate wild type (WT) rats. We demonstrated that CNP-KO rats were useful as a reproducible animal model for skeletal dysplasia, due to their impairment in endochondral bone growth. There was no significant difference in plasma bone-turnover markers between the CNP-KO and WT rats. At eight weeks of age, growth plate closure was observed in the distal end of the tibia and the calcaneus of CNP-KO rats. Continuous subcutaneous infusion of CNP-53 significantly, and in a dose-dependent manner, stimulated skeletal growth in CNP-KO and WT rats, with CNP-KO rats being more sensitive to the treatment. CNP-53 also normalized the length of long bones and the growth plate thickness, and prevented growth plate closure in the CNP-KO rats. Using organ culture experiment of fetal rat tibia, gene set enrichment analysis indicated that CNP might have a negative influence on mitogen activated protein kinase signaling cascades in chondrocyte. Our results indicated that CNP-KO rats might be a valuable animal model for investigating growth plate physiology and the mechanism of growth plate closure, and that CNP-53, or its analog, may have the potential to promote growth and to prevent early growth plate closure in the short stature.

Live imaging analysis of the growth plate in a murine long bone explanted culture system.

Skeletal growth in mammals, which owes the growth of an individual, occurs at the growth plate and to observe and analyze its dynamic growth is of high interest. Here we performed live imaging analysis of the growth plate of a fetal murine long bone organ culture using two-photon excitation microscopy. We could observe a dynamic growth of the growth plate of explanted fetal murine ulna, as well as the resultant linear elongation of the explants. As for the factors contributing to the elongation of the growth plate, the displacement length of each chondrocyte was larger in the prehypertrophic or hypertrophic zone than in the proliferative zone. The segmented area and its extracellular component were increased in both the proliferative and prehypertrophic-hypertrophic zones, whereas an increase in cellular components was only seen in the prehypertrophic-hypertrophic zone. C-type natriuretic peptide, a known positive stimulator of endochondral bone growth mainly targeting prehypertrophic-hypertrophic zone, augmented all of the factors affecting growth plate elongation, whereas it had little effect on the proliferation of chondrocytes. Collectively, the axial trajectory of each chondrocyte mainly owes cellular or extracellular expansion especially in prehypertrophic-hypertrophic zone and results in growth plate elongation, which might finally result in endochondral bone elongation.