鈴木 敦詞

OBJECTIVES: Phosphate (Pi) induces differentiation of arterial smooth muscle cells to the osteoblastic phenotype by inducing the type III Na-dependent Pi transporter Pit-1/solute carrier family member 1. This induction can contribute to arterial calcification, but precisely how Pi stress acts on the vascular wall remains unclear. We investigated the role of extracellular Pi in inducing microstructural changes in the arterial wall. METHODS: Aortae of Pit-1-overexpressing transgenic (TG) rats and their wild-type (WT) littermates were obtained at 8 weeks after birth. The thoracic descending aorta from WT and TG rats was used for the measurement of wall thickness and uniaxial tensile testing. Structural and ultrastructural analyses were performed using light microscopy and transmission electron microscopy. Gene expression of connective tissue components in the aorta was quantified by quantitative real-time polymerase chain reaction. RESULTS: Aortic wall thickness in TG rats was the same as that in WT rats. Uniaxial tensile testing showed that the circumferential breaking stress in TG rats was significantly lower than that in WT rats (p<0.05), although the longitudinal breaking stress, breaking strain, and elastic moduli in both directions in TG rats were unchanged. Transmission electron microscopy analysis of the aorta from TG rats showed damaged formation of elastic fibers in the aortic wall. Fibrillin-1 gene expression levels in the aorta were significantly lower in TG rats than in WT rats (p<0.05). CONCLUSIONS: Pi overload acting via the arterial wall Pit-1 transporter weakens circumferential strength by causing elastic fiber malformation, probably via decreased fibrillin-1 expression.

Coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2, and various complications have been reported. Furthermore, there have been increasing reports of endocrinopathy related to COVID-19 following the pandemic. We report a 49-year-old healthy woman who developed rapid onset of polydipsia and polyuria three weeks after COVID-19. Laboratory tests indicated low urine osmolarity and increased serum osmolarity, and antidiuretic hormone (ADH) was undetectable. Urine osmolality remained low with water deprivation. Similarly, plasma ADH responses to hypertonic-saline infusion were blunted and urine osmolality increased in response to desmopressin. There was no clear evidence of anterior pituitary dysfunction. T1-weighted magnetic resonance imaging (MRI) showed pituitary stalk thickening and absence of posterior pituitary bright signal spots, suggesting the presence of hypophysitis. Based on these results, we made a probable diagnosis of lymphocytic infundibulo-neurohypophysitis (LINH) which have caused central diabetes insipidus. Positive findings for serum anti-rabphilin-3A antibodies, reported as a potential diagnostic marker for LINH, were also noted. Following oral desmopressin administration, polydipsia and polyuria were quickly improved, though treatment with desmopressin was still required over four months. This is the first report of a patient with a probable diagnosis of LINH after COVID-19 who tested positive for anti-rabphilin-3A antibodies. Positive findings for those antibodies suggest that pituitary dysfunction associated with COVID-19 is hypophysitis involving an abnormal immune mechanism. The presence of anti-rabphilin-3A antibodies may be useful as a non-invasive diagnostic marker of LINH and potentially serve as a valuable diagnostic aid in cases of LINH associated with COVID-19.

Hyponatremia is the most common clinical electrolyte disorder. Chronic hyponatremia has been recently reported to be associated with falls, fracture, osteoporosis, neurocognitive impairment, and mental manifestations. In the treatment of chronic hyponatremia, overly rapid correction of hyponatremia can cause osmotic demyelination syndrome (ODS), a central demyelinating disease that is also associated with neurological morbidity and mortality. Using a rat model, we have previously shown that microglia play a critical role in the pathogenesis of ODS. However, the direct effect of rapid correction of hyponatremia on microglia is unknown. Furthermore, the effect of chronic hyponatremia on microglia remains elusive. Using microglial cell lines BV-2 and 6-3, we show here that low extracellular sodium concentrations (36 mmol/L decrease; LS) suppress Nos2 mRNA expression and nitric oxide (NO) production of microglia. On rapid correction of low sodium concentrations, NO production was significantly increased in both cells, suggesting that acute correction of hyponatremia partly directly contributes to increased Nos2 mRNA expression and NO release in ODS pathophysiology. LS also suppressed expression and nuclear translocation of nuclear factor of activated T cells-5 (NFAT5), a transcription factor that regulates the expression of genes involved in osmotic stress. Furthermore, overexpression of NFAT5 significantly increased Nos2 mRNA expression and NO production in BV-2 cells. Expressions of Nos2 and Nfat5 mRNA were also modulated in microglia isolated from cerebral cortex in chronic hyponatremia model mice. These data indicate that LS modulates microglial NO production dependent on NFAT5 and suggest that microglia contribute to hyponatremia-induced neuronal dysfunctions.

BACKGROUND: Arginine vasopressin deficiency (AVP-D) can occur due to various conditions, so clarifying its cause is important for deciding treatment strategy. Although several cases of AVP-D following coronavirus disease 2019(COVID-19) infection or COVID-19 vaccination have been reported, the diagnosis of the underlying disease has not been reported in most cases. CASE PRESENTATION: A 75-year-old woman who presented with polydipsia and polyuria 9 weeks after contracting COVID-19 and 5 weeks after receiving the SARS-CoV-2 vaccination, leading to the final diagnosis of AVP-D 8 months after the first appearance of symptoms. Interestingly, pituitary magnetic resonance imaging (MRI) still revealed stalk enlargement frequently observed in patients with SARS-CoV-2 vaccination-induced AVP-D. Although this finding could not rule out any malignancies, we additionally measured anti-rabphilin-3A antibodies, a known marker for lymphocytic infundibulo-neurohypophysitis (LINH), and found that the results were positive, strongly suggesting LINH as the cause of this disease. Thus, we avoided pituitary biopsy. At the follow-up MRI conducted 12 months after the initial consultation, enlargement of the pituitary stalk was still observed. CONCLUSION: We experienced a case with LINH probably induced by SARS-CoV-2 vaccination. In SARS-CoV-2 vaccination-related LINH, unlike typical LINH, there is a possibility of persistent pituitary stalk enlargement on MRI images for an extended period, posing challenges in differential diagnosis from other conditions. Pituitary stalk enlargement and positive anti-rabphilin-3A antibodies may help in the diagnosis of AVP-D induced by SARS-CoV-2 vaccination.

Signs and symptoms of hypernatremia largely indicate central nervous system dysfunction. Acute hypernatremia can cause demyelinating lesions similar to that observed in osmotic demyelination syndrome (ODS). We have previously demonstrated that microglia accumulate in ODS lesions and minocycline protects against ODS by inhibiting microglial activation. However, the direct effect of rapid rise in the sodium concentrations on microglia is largely unknown. In addition, the effect of chronic hypernatremia on microglia also remains elusive. Here, we investigated the effects of acute (6 or 24 h) and chronic (the extracellular sodium concentration was increased gradually for at least 7 days) high sodium concentrations on microglia using the microglial cell line, BV-2. We found that both acute and chronic high sodium concentrations increase NOS2 expression and nitric oxide (NO) production. We also demonstrated that the expression of nuclear factor of activated T-cells-5 (NFAT5) is increased by high sodium concentrations. Furthermore, NFAT5 knockdown suppressed NOS2 expression and NO production. We also demonstrated that high sodium concentrations decreased intracellular Ca2+ concentration and an inhibitor of Na+/Ca2+ exchanger, NCX, suppressed a decrease in intracellular Ca2+ concentrations and NOS2 expression and NO production induced by high sodium concentrations. Furthermore, minocycline inhibited NOS2 expression and NO production induced by high sodium concentrations. These in vitro data suggest that microglial activity in response to high sodium concentrations is regulated by NFAT5 and Ca2+ efflux through NCX and is suppressed by minocycline.

CONTEXT: The mortality rate in thyroid storm (TS) has been reported to be higher than 10%. OBJECTIVE: We aimed to evaluate the effectiveness of the 2016 guidelines for the management of TS proposed by the Japan Thyroid Association and Japan Endocrine Society. DESIGN: Prospective registry-based study through a secure web platform. SETTING: Prospective multicenter registry. PATIENTS AND MEASUREMENTS: Patients with new-onset TS were registered in the Research Electronic Data Capture (REDCap). On day 30 after admission, clinical information and prognosis of each patient were added to the platform. On day 180, the prognosis was described. RESULTS: This study included 110 patients with TS. The median of Acute Physiology and Chronic Health Evaluation (APACHE) II score was 13, higher than the score in the previous nationwide epidemiological study, 10 (p = 0.001). Nonetheless, the mortality rate at day 30 was 5.5%, approximately half compared with 10.7% in the previous nationwide survey. Lower body mass index, shock and lower left ventricular ejection fraction were positively associated with poor prognosis at day 30, while the lack of fever ≥ 38℃ was related to the outcome. The mortality rate in patients with an APACHE II score ≥12 for whom the guidelines were not followed was significantly higher than the rate in patients for whom the guidelines were followed (50% vs. 4.7%) (p = 0.01). CONCLUSIONS: Prognosis seemed better than in the previous nationwide survey, even though disease severity was higher. The mortality rate was lower when the guidelines were followed. Thus, the guidelines are useful for managing TS.

The condition of being underweight is a social problem in Japan among women. However, there is a lack of evidence for dietary guidance for underweight women because there has been no comparison of lipids or HbA1c among underweight, normal weight, and overweight women in different age groups. We analyzed the effect of body size and age on the serum lipid and hemoglobin A1c levels in Japanese women in a cross-sectional study. A total of 26,118 women aged >20-65 years underwent physical examinations between 2012 and 2022. Seventeen percent of women aged >20-29 years were underweight, and 8% of those aged 50-65 years were underweight. Total cholesterol and non-HDL-C concentrations increased with age, but the difference between underweight and overweight individuals was lowest among women aged 50-65 years. On the other hand, the differences in HDL-C, TG, and HbA1c levels between underweight and overweight subjects were greatest in the 50-65 age group, but the differences between underweight and normal weight subjects were much smaller. Considering that, unlike HDL-C, TG, and HbA1c, TC and non-HDL-C increase to levels comparable to overweight levels in underweight women in aged 50-65 years, educating people about a diet that lowers non-HDL-C is necessary even in young underweight women.

BACKGROUND: Gestational diabetes insipidus (DI) is a very rare complication of pregnancy. We present a case of gestational DI combining two different types of DI. Case Presentation. A 39-year-old pregnant woman suddenly presented with thirst, polydipsia, and polyuria after 31 gestation weeks (GWs). Based on laboratory findings of hypotonic urine (78 mOsm/kgH2O) with higher plasma osmolality (298 mOsm/kgH2O) and higher serum sodium levels (149 mEq/L), gestational DI was suspected, and the clinical course was monitored without therapy until the results of a measurement of plasma arginine vasopressin (AVP) levels were available. However, she subsequently developed acute prerenal failure and underwent an emergency cesarean section at 34 GWs. Her resected placenta weighed 920 g, nearly twice the normal weight. Immediately following delivery, intranasal 1-desamino-8-D-arginine vasopressin was administered, and her symptoms promptly disappeared. Afterward, her predelivery plasma AVP level was found to have been inappropriately low (0.7 pg/mL) given her serum sodium level. The patient's serum vasopressinase level just before delivery was 2,855 ng/mL, more than 1,000 times the upper limit of the normal range, suggesting excess vasopressinase-induced DI. The presence of anti-rabphilin-3A antibodies in the patient's blood, a hypertonic saline infusion test result, and loss of the high-intensity signal of the posterior pituitary on fat-suppressed T1-weighted magnetic resonance images without thickening of the stalk and enlargement of the neurohypophysis suggested concurrent central DI-like lymphocytic infundibulo-neurohypophysitis (LINH). CONCLUSION: In addition to the degradation of AVP by excess placental vasopressinase due to the enlarged placenta, an insufficient compensatory increase in AVP secretion from the posterior pituitary gland due to LINH-like pathogenesis might have led to DI symptoms.

BACKGROUND: Intramuscular adipose tissue (IMAT) formation derived from muscle fibro-adipogenic progenitors (FAPs) has been recognized as a pathological feature of sarcopenia. This study aimed to explore whether genetic and pharmacological gastric inhibitory polypeptide (GIP) receptor antagonism suppresses IMAT accumulation and ameliorates sarcopenia in mice. METHODS: Whole body composition, grip strength, skeletal muscle weight, tibialis anterior (TA) muscle fibre cross-sectional area (CSA) and TA muscle IMAT area were measured in young and aged male C57BL/6 strain GIP receptor (Gipr)-knockout (Gipr-/- ) and wild-type (Gipr+/+ ) mice. FAPs isolated from lower limb muscles of 12-week-old Gipr+/+ mice were cultured with GIP, and their differentiation into mature adipocytes was examined. Furthermore, TA muscle IMAT area and fibre CSA were measured in untreated Gipr-/- mice and GIP receptor antagonist-treated Gipr+/+ mice after glycerol injection into the TA muscles. RESULTS: Body composition analysis revealed that 104-week-old Gipr-/- mice had a greater proportion of lean tissue mass (73.7 ± 1.2% vs. 66.5 ± 2.7%, P < 0.05 vs. 104-week-old Gipr+/+ mice) and less adipose tissue mass (13.1 ± 1.3% vs. 19.4 ± 2.6%, P < 0.05 vs. 104-week-old Gipr+/+ mice). Eighty-four-week-old Gipr-/- mice exhibited increases in grip strength (P < 0.05), weights of TA (P < 0.05), soleus (P < 0.01), gastrocnemius (P < 0.05) and quadriceps femoris (P < 0.01) muscles, and average TA muscle fibre CSA (P < 0.05) along with a reduction in TA muscle IMAT area assessed by the number of perilipin-positive cells (P < 0.0001) compared with 84-week-old Gipr+/+ mice. Oil Red O staining analysis revealed 1.6- and 1.7-fold increased adipogenesis in muscle FAPs cultured with 10 and 100 nM of GIP (P < 0.01 and P < 0.001 vs. 0 nM of GIP, respectively). Furthermore, both untreated Gipr-/- mice and GIP receptor antagonist-treated Gipr+/+ mice for 14 days after glycerol injection into the TA muscles at 12 weeks of age showed reduced TA muscle IMAT area (1.39 ± 0.38% and 2.65 ± 0.36% vs. 6.54 ± 1.30%, P < 0.001 and P < 0.01 vs. untreated Gipr+/+ mice, respectively) and increased average TA muscle fibre CSA (P < 0.01 and P < 0.05 vs. untreated Gipr+/+ mice, respectively). CONCLUSIONS: GIP promotes the differentiation of muscle FAPs into adipocytes and its receptor antagonism suppresses IMAT accumulation and promotes muscle regeneration. Pharmacological GIP receptor antagonism may serve as a novel therapeutic approach for sarcopenia.

Childhood-onset lymphocytic infundibuloneurohypophysitis (LINH) has rarely been reported. Pathological evaluation via pituitary biopsy is necessary for a definitive diagnosis of LINH. However, pituitary biopsy is a highly invasive procedure. Recently, anti-rabphilin-3A antibody (RPH3A-Ab) has been reported as a promising diagnostic marker for LINH in adults; however, there are few such reports in the pediatric population. We report the case of an 8-year-old boy with central diabetes insipidus (CDI) who was clinically diagnosed with LINH based on RPH3A-Ab positivity. He was diagnosed with CDI using a water deprivation test combined with desmopressin administration. Serum and cerebrospinal fluid tumor markers were negative, and T1-weighted magnetic resonance imaging (MRI) revealed the absence of high signal intensity in the posterior pituitary gland and an enlarged pituitary stalk. Anterior pituitary function tests revealed no abnormalities. No pituitary biopsy was performed because of its invasive nature, and desmopressin treatment was initiated. Three months after CDI onset, the patient tested positive for RPH3A-Ab. MRI performed 9 months after CDI onset revealed amelioration of the pituitary stalk enlargement, and the clinical course corroborated our diagnosis of LINH. RPH3A-Ab may be useful as an early diagnostic tool for LINH in the pediatric population.

Abstract Background Central diabetes insipidus (CDI) is a rare condition caused by various underlying diseases, including neoplasms, autoimmune diseases, and infiltrative diseases. Differentiating between CDI etiologies is difficult. What has initially been classified as “idiopathic” central diabetes insipidus might in fact underlie various pathogenic mechanisms that are less understood to date and/or are not obvious at initial presentation. Therefore, even if idiopathic CDI is diagnosed at the time of onset, it is common for tumors such as germinoma to develop during surveillance. Crucially, a delayed diagnosis of germinoma may be associated with a worse prognosis. Recently, the presence of anti–rabphilin-3A antibodies has been found to be a highly sensitive and specific marker of lymphocytic infundibuloneurohypophysitis, an autoimmune-mediated CDI. Case presentation We herein present two cases, namely, a 13-year-old boy (patient 1) and a 19-year-old young man (patient 2) who were diagnosed with idiopathic CDI. In both patients, panhypopituitarism developed. Magnetic resonance imaging revealed pituitary stalk thickening and pituitary swelling approximately 1 1/2 years after the onset of CDI. Western blotting did not reveal the presence of anti-rabphilin-3A antibodies in serum in either patient, suggesting that autoimmune mechanisms might not be involved. Both patients were subsequently diagnosed with germinoma on pathological examination. They received chemotherapy, followed by radiation therapy. Notably, testosterone and insulin-like growth factor-1 levels normalized, and libido and beard growth recovered after chemoradiotherapy in patient 2. Conclusion Our data suggest that the absence of anti-rabphilin-3A antibodies in young patients clinically diagnosed with idiopathic CDI may increase the probability of the development of non-lymphocytic lesions, including germinoma. We thus recommend a more attentive approach at the onset of these diseases.

A 36-year-old female was pointed out to have liver enzyme elevation by routine health checkup. Subsequent contrast-enhanced CT scan identified gigantic uterine fibroids and retroperitoneal tumor. She was referred to the gynecologist at JA Toride Medical Center and planned to undergo a uterus enucleation and biopsy of the retroperitoneal tumor. The surgery was conducted without any troubles. After the surgery, the patient presented polyuria with urine volume 10-20 L a day and developed hypovolemic shock. Laboratory test revealed hypotonic urine and hypernatremia. Arginine vasopressin (AVP) loading test suggested shortage of endogenous vasopressin. Since the subcutaneous administration of AVP was not sufficient to control the urine volume, continuous intravenous infusion of AVP was initiated. After achieving hemodynamic stability, the treatment was switched to oral desmopressin. MRI finding indicated attenuation of high signal in posterior pituitary in T1 weighted image while neither enlargement of pituitary nor thickening of pituitary stalk was indicated by enhanced MRI. Hypertonic salt solution test indicated no responsive elevation of AVP, confirming the diagnosis of central diabetes insipidus (CDI). Her anterior pituitary function was preserved. Only anti-rabphilin-3A antibody was found positive in the serum of the patient, while other secondary causes for CDI were denied serologically and radiologically. Hence, lymphocytic infundibuloneurohypophysitis (LINH) was suspected as the final diagnosis. Hormonal replacement therapy by nasal desmopressin was continued and the patient managed to control her urine volume. In cases of CDI considered idiopathic with conventional examinations, anti-rabphilin-3A antibody may be a clue for determining the cause as LINH.

OBJECTIVES: Type 1 diabetes mellitus (T1DM) patients with diabetic kidney disease-induced kidney failure have a significantly impaired quality of life (QOL), resulting in a high level of physical, mental, and social anxiety. In this study, we evaluated the QOL of T1DM patients on the list for pancreas transplantation (PTx) at their registration, and determined whether PTx improved their QOL. METHODS: There were 58 patients (men/women, 22/36; mean age, 42.8±8.0 years) with T1DM and who were registered on the waiting list for PTx. Quantitative QOL assessment was performed using the Medical Health Survey Short Form (SF-36) version 2. Changes in the QOL before and after PTx were also examined in 24 of these patients. RESULTS: The mean value of each endpoint and the summary score of the SF-36 physical (PCS), mental (MCS), and role (RCS) components were all below the national normal level at PTx registration. No significant difference in QOL scores was observed in the intergroup comparison of 35 patients on dialysis, 13 patients without dialysis, and ten patients after kidney transplantation. The 24 patients who underwent PTx showed improvement in PCS, MCS, and most SF-36 scores. CONCLUSION: T1DM patients waiting for PTx had a decreased QOL, regardless of dialysis, and PTx improved their QOL.

AIMS/INTRODUCTION: Glucagon is secreted from pancreatic α-cells and plays an important role in amino acid metabolism in liver. Various animal models deficient in glucagon action show hyper-amino acidemia and α-cell hyperplasia, indicating that glucagon contributes to feedback regulation between the liver and the α-cells. In addition, both insulin and various amino acids, including branched-chain amino acids and alanine, participate in protein synthesis in skeletal muscle. However, the effect of hyperaminoacidemia on skeletal muscle has not been investigated. In the present study, we examined the effect of blockade of glucagon action on skeletal muscle using mice deficient in proglucagon-derived peptides (GCGKO mice). MATERIALS AND METHODS: Muscles isolated from GCGKO and control mice were analyzed for their morphology, gene expression and metabolites. RESULTS: GCGKO mice showed muscle fiber hypertrophy, and a decreased ratio of type IIA and an increased ratio of type IIB fibers in the tibialis anterior. The expression levels of myosin heavy chain (Myh) 7, 2, 1 and myoglobin messenger ribonucleic acid were significantly lower in GCGKO mice than those in control mice in the tibialis anterior. GCGKO mice showed a significantly higher concentration of arginine, asparagine, serine and threonine in the quadriceps femoris muscles, and also alanine, aspartic acid, cysteine, glutamine, glycine and lysine, as well as four amino acids in gastrocnemius muscles. CONCLUSIONS: These results show that hyperaminoacidemia induced by blockade of glucagon action in mice increases skeletal muscle weight and stimulates slow-to-fast transition in type II fibers of skeletal muscle, mimicking the phenotype of a high-protein diet.

Undernutrition among young women at “Cinderella weight” is socially important in Japan. To determine the nutritional status of Cinderella-weight women, we conducted an exploratory cross-sectional study on the health examination results of employees aged 20 to 39 (n = 1457 and 643 for women and men, respectively). The percentage of underweight women was found to be much higher than that of men (16.8% vs. 4.5%, respectively). In underweight women (n = 245), handgrip strength (22.82 ± 5.55 vs. 25.73 ± 5.81 kg, p &lt; 0.001), cholesterol level (177.8 ± 25.2 vs. 194.7 ± 31.2 mg/dL, p &lt; 0.05), and lymphocyte count (1883 ± 503 vs. 2148 ± 765/μL, p &lt; 0.001) were significantly lower than in overweight women (n = 116). Then, the BMI &lt; 17.5 group (n = 44) was referred to the outpatient nutrition evaluation clinic. Lower prealbumin, cholesterol, and lymphocyte levels were also observed in 34%, 59%, and 32% of the patients, respectively. Regarding dietary characteristics, 32% of the underweight women in this study skipped breakfast, and 50% had low dietary diversity scores. Lower total energy intake, carbohydrate and fiber intake, and Ca and Fe intake were also observed in 90% of the patients. Deficiencies in vitamin B1, B12, D, and folate were diagnosed in 4.6%, 25%, 14%, and 98% of the patients, respectively. Thus, young underweight women may be prone to malnutrition.

症例は34歳男性で、倦怠感、多尿を主訴に、下垂体前葉機能低下、中枢性尿崩症を認め、汎下垂体機能低下症と診断した。診断後はヒドロコルチゾン、レボチロキシン、デスモプレシン点鼻薬の補充により倦怠感や多尿は改善した。頭部Gd造影MRIで下垂体から下垂体茎、視床下部にかけて腫大を認め、下垂体生検よりリンパ球性汎下垂体炎が考えられた。胚細胞腫の好発年齢であり、鑑別に血清抗rabphilin-3A抗体をウェスタンブロット法で測定したところ陽性で、リンパ球性汎下垂体炎と診断した。上記の補充療法とともにhCG投与を行い、現在も経過観察中である。