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Biomedical subjects

Takaaki Abe

Publications and source records attributed to Takaaki Abe.

At least 19 recordsLinked to original sources

Genetic Testing Unveils a Novel Thrombospondin-1 Domain Containing Protein 1 Gene Variant as the Cause of Chronic Edema in a 79-Year-Old Woman.

Edema requires management tailored to its underlying etiology; however, in some cases the cause remains elusive. We describe a 79-year-old woman with lifelong unexplained peripheral edema. Comprehensive evaluation excluded common etiologies such as heart failure, renal dysfunction, and venous thrombosis. Whole-genome sequencing identified a novel homozygous splice-site variant (NM_018676.4:c.58+2T>G) in the thrombospondin-1 domain-containing protein 1 (THSD1) gene, which has previously been associated with non-immune hydrops fetalis (NIHF). This report describes, to our knowledge, the first elderly patient with chronic peripheral edema harboring a likely pathogenic THSD1 variant, suggesting that THSD1-related disease may, in rare instances, persist beyond the perinatal period and present into late adulthood. Although causality cannot be established definitively from a single case, the findings highlight the potential utility of genetic testing in adults with chronic unexplained edema.

chronic edema↗

An oral tyrosine challenge test for functional phenotyping of microbiota-derived phenyl sulfate production.

Phenyl sulfate (PS), a gut microbiota-derived metabolite implicated in the pathogenesis of diabetic kidney disease, is generated through microbial conversion of dietary tyrosine to phenol, followed by hepatic sulfation via SULT1A1. We developed an oral tyrosine challenge test (OTyCT) to phenotype individual PS-producing capacity. Forty-eight healthy adults underwent a standardized tyrosine load with serial plasma PS levels measured over 48 h using LC-MS. OTyCT revealed substantial interindividual variability of PS production independent of baseline PS levels, highlighting marked heterogeneity in host-microbiome metabolic interactions. Sixteen participants in the highest tertile of the incremental area under the curve of PS were defined as high-PS producers. High PS producers exhibited distinct gut microbial signatures despite comparable abundances of known phenol-biosynthetic genes and host SULT1A1 genotypes. These findings suggest that susceptibility to PS-related complications may vary according to gut microbial profiles, supporting OTyCT as a practical tool for metabolic phenotyping and microbiome-informed precision nutrition. Clinical Trial registry name and registration number: Identification of P-Cresyl Sulfate Producer Phenotype by Oral Tyrosine Challenge Test: Interactions Among Diet, Gut Microbiota, and Host Genome, NCT04204174.

Journal Article↗

Expression of organic cation transporter SLC22A16 in human endometria.

SLC22A16 is one of newly isolated organic cation transporters, which is responsible for uptake and transport of adriamycin into cells. Adriamycin is one of the key drugs for treatment of endometrial cancer. Therefore, we examined expression of SLC22A16 in human endometrium and its disorders. Protein and mRNA expression levels of SLC22A16 were examined in 124 endometrial cancer specimens, 25 normal endometrial tissue samples (15 in proliferative phase, 10 in secretory phase), and 7 endometrial cancer cell lines using immunohistochemical analysis and reverse transcription-polymerase chain reaction. Changes in SLC22A16 mRNA expression level after progesterone exposure were also examined. Immunohistochemical analysis showed that SLC22A16 protein was highly expressed in endometrium during the normal secretory phase, but its level was significantly reduced in the proliferative phase. SLC22A16 protein was detected in 59 of 124 (48%) endometrial cancer specimens and 3 of 7 (43%) endometrial cancer cell lines. The mRNA levels measured by quantitative reverse transcription-polymerase chain reaction were comparable with levels of protein expression. Furthermore, SLC22A16 mRNA levels were increased in endometrial cancer cell lines in the presence of progesterone. In conclusion, SLC22A16 is expressed in various endometrial tissues. Its expression level is high during the secretory phase and may be regulated by progesterone. Our findings also suggest that it may be possible to use progestins to increase the response of endometrioid endometrial carcinoma with SLC22A16 expression to adriamycin-based chemotherapeutic regimens.

Cell Line, Tumor↗

A case surviving for over a year of renal tubular dysgenesis with compound heterozygous angiotensinogen gene mutations.

Renal tubular dysgenesis (RTD) is a developmental abnormality of the renal proximal tubules found in patients with Potter syndrome. We report a female newborn with RTD who has survived for more than 18 months. Infusions of fresh frozen plasma (FFP) in the early neonatal period were effective in raising and maintaining her blood pressure. Peritoneal dialysis was required until the appearance of spontaneous urination at 29 days after birth. Histopathological examinations of the kidney revealed dilated renal tubular lumina and foamy columnar epithelial cells in the renal tubules. Endocrinological studies showed a discrepancy between low plasma renin activity (<0.1 ng/ml/hr) and high active renin concentration (135,000 pg/ml), suggesting an aberration in the renin substrate, angiotensinogen. Direct sequencing analysis revealed two novel mutations in the coding region of the angiotensinogen gene (AGT): a nonsense mutation in exon 2 (c.604C > T) and a frameshift deletion at nucleotide 1290 in exon 5 (c.1290delT). The mutations were in the compound heterozygous state, because each parent had each mutation. These findings suggest that angiotensinogen deficiency is one of the causes of RTD. A treatment of the condition with FFP may help to promote long survival.

Angiotensinogen↗

Transport of fluorescent chenodeoxycholic acid via the human organic anion transporters OATP1B1 and OATP1B3.

This study sought to clarify the contributions of organic anion-transporting polypeptide (OATP) 1B1 and 1B3 to the liver uptake of chenodeoxycholic acid (CDCA). We synthesized a fluorescent version of CDCA, chenodeoxychilyl-(Nepsilon-NBD)-lysine (CDCA-NBD), to characterize transporter-mediated uptake. CDCA-NBD is efficiently transported by OATP1B1 and OATP1B3 with high affinities. The Michaelis-Menten constants for CDCA-NBD uptake by OATP1B1 and OATP1B3 were 1.45 +/- 0.39 microM and 0.54 +/- 0.09 microM, respectively. By confocal laser scanning microscopy, CDCA-NBD, which is taken up by OATP1B1 and OATP1B3, was observed to localize to the cytosol. We also examined the transport of newly synthesized fluorescent bile acids. NBD-labeled bile acids, including cholic acid, deoxycholic acid, lithocholic acid, and ursodeoxycholic acid, were all transported by OATP1B1 and OATP1B3. CDCA-NBD exhibited the highest rate of transport of the five NBD-labeled bile acids examined in OATP1B1- and OATP1B3-expressing cells. Our results suggest that OATP1B1 and OATP1B3 play important roles in CDCA uptake into the liver. Fluorescent bile acids are useful tools to characterize the uptake properties of membrane transporters.

Bile Acids and Salts↗

OATP1B1, OATP1B3, and mrp2 are involved in hepatobiliary transport of olmesartan, a novel angiotensin II blocker.

Hepatic uptake and biliary excretion of olmesartan, a new angiotensin II blocker, were investigated in vitro using human hepatocytes, cells expressing uptake transporters and canalicular membrane vesicles, and in vivo using Eisai hyperbilirubinemic rats (EHBR), inherited multidrug resistance-associated protein (mrp2)-deficient rats. The uptake by human hepatocytes reached saturation with a Michaelis constant (K(m)) of 29.3 +/- 9.9 microM. Both Na(+)-dependent and Na(+)-independent uptake of olmesartan by human hepatocytes were observed. The uptake by Na(+)-independent human liver-specific organic anion transporters OATP1B1 and OATP1B3 expressed in Xenopus laevis oocytes was also saturable, with K(m) values of 42.6 +/- 28.6 and 71.8 +/- 21.6 microM, respectively. The Na(+)-dependent taurocholate-cotransporting polypeptide expressed in HEK 293 cells did not transport olmesartan. The cumulative biliary excretion in EHBR was one-sixth compared with that in Sprague-Dawley rats. ATP-dependent uptake of olmesartan was observed in both human canalicular membrane vesicles (hCMVs) and MRP2-expressing vesicles. An MRP inhibitor, MK-571 ([[[3-[2-(7-chloro-2-quinolinyl)ethenyl]phenyl][3-(dimethylamino)-3-oxopropyl]thio]methyl]thio]-propanoic acid) completely inhibited the uptake of olmesartan by hCMVs. In conclusion, the hepatic uptake and biliary excretion of olmesartan are mediated by transporters in humans. OATP1B1 and OATP1B3 are involved in hepatic uptake, at least in part, and MRP2 plays a dominant role in the biliary excretion.

Angiotensin II↗

Farnesoid X receptor, hepatocyte nuclear factors 1alpha and 3beta are essential for transcriptional activation of the liver-specific organic anion transporter-2 gene.

BACKGROUND: We isolated the human liver-specific organic anion transporter gene, LST-2 (OATP8/SLCO1B3), which is exclusively expressed in the basolateral membrane of the hepatocytes. In this study, we analyzed the transcriptional regulation of the LST-2 gene in hepatocyte-derived cells and the effect of bile acid. METHODS: Transcriptional activity of the LST-2 gene was measured using a human LST-2 promoter-luciferase reporter plasmid under various concentrations of bile acids. Electrophoresis mobility shift assays of farnesoid X receptor (FXR), hepatocyte nuclear factor (HNF) 1alpha, and HNF3beta were performed. RESULTS: Luciferase analysis showed that the 5'-flanking region from -180 to -20 bp is responsible for LST-2 transcriptional activity. By site-directed mutation analysis, it was revealed that the consensus binding sites for FXR, HNF1alpha, and HNF3beta play important roles in the transcriptional activity of the LST-2 gene. By electrophoresis mobility shift assay, we observed specific protein-DNA complexes of FXR, HNF1alpha, and HNF-3beta. Luciferase activity was increased fivefold when chenodeoxycholate or deoxycholate were added. Northern blot analyses revealed that the expression of LST-2 was increased by addition of chenodeoxycholate or deoxycholate in a dose-dependent manner. CONCLUSIONS: This study demonstrated that the transcription of the LST-2 gene is regulated by three transcription factors, FXR, HNF1alpha, and HNF3beta. HNF1alpha and HNF3beta might contribute to its liver-specific expression, and FXR might play a role in its transcriptional activation by bile acids.

Bile Acids and Salts↗

Long-term clinical course of patients with acute polymorphic psychotic disorder without symptoms of schizophrenia.

Few studies have investigated the long-term course of patients with acute polymorphic psychotic disorder, despite the clinical relevance. The present study focused on the frequency of acute polymorphic psychotic disorder without symptoms of schizophrenia (F23.0) and the prognosis of patients with the disorder over a long period. A total of 388 inpatients with nonaffective psychosis were examined and cases with F23.0 were retrospectively investigated regarding clinical course over 12 years with reference to clinical charts. A total of 16 cases were diagnosed with F23.0 according to first episode. After 12 years, five cases were rediagnosed with schizophrenia, and one case with borderline-type emotionally unstable personality disorder, although the diagnosis of F23.0 was not changed in 10 older patients. Of the four cases with >2 repeated episodes of F23.0, the same clinical picture as in the first episode was observed in three, while one case showed continuous residual symptoms. F23.0 does not represent a homogeneous clinical entity. In some cases, diagnosis changes to schizophrenia, but others display repeated episodes of F23.0.

Adolescent↗

[Nosological status of the intermediate area between schizophrenia and affective disorder].

Non-organic psychoses diagnosed with neither schizophrenia nor affective disorder are an aggregation of heterogeneous psychotic disorders including major groups such as acute polymorphic psychotic disorders and schizoaffective disorders. Historically, similar psychotic pictures have been reported in various cultures. However, their slightly different definition hindered comparative studies. Even after the establishment of an operational diagnostic guideline such as ICD-10, epidemiological studies on this intermediate area between schizophrenia and affective disorder have brought different findings, making the reliability of diagnosis of this area questionable. Moreover, the situation is further complicated that there exists not only cases which have repeated the same episode as the first, but also cases whereby the diagnosis has been changed to schizophrenia or affective disorder over a long-term course. K. Schneider, who suggested not differential diagnosis but differential typology in the area of endogenous psychoses, is right in thinking of the existence of this intermediate area. We should be satisfied with making a provisional diagnosis, should take a flexible attitude towards changes in diagnosis between episodes. And during diagnosis, we should not differentiate schizophrenia from affective disorders rigidly, nor define the intermediate area strictly.

Diagnosis, Differential↗

Characterization of the organic cation transporter SLC22A16: a doxorubicin importer.

Specific efflux transporters, such as P-glycoprotein, have been shown to confer drug resistance by decreasing the intracellular accumulation of anticancer drugs. Understanding influx transporters, as well as efflux transporters, is essential to overcome this resistance. We report the expression profile and pharmacological characterization of an organic cation transporter, SLC22A16. The results of our experiments indicate that SLC22A16 is a mediator of doxorubicin uptake in cancer cells. Quantitative real-time RT-PCR analyses show that SLC22A16 is expressed in primary samples taken from patients with acute leukemia. Xenopus oocytes injected with SLC22A16 cRNA import doxorubicin, a widely used anticancer drug for hematological malignancies, in a saturable and dose-dependent manner. The apparent Km value for doxorubicin import was 5.2+/-0.4 microM. In cytotoxic assays, stable transfectants of leukemic Jurkat cells overexpressing SLC22A16 cells became significantly more sensitive to doxorubicin (2 microM) treatment. Characterization of SLC22A16 will help in designing novel therapies targeting hematological malignancies.

Antibiotics, Antineoplastic↗

PDZ-binding and di-hydrophobic motifs regulate distribution of Kir4.1 channels in renal cells.

It was shown previously that the carboxyl-terminal cytoplasmic portion of Kir4.1 determines the localization of basolateral K+ channel in renal distal tubules, which is composed from the assembly of Kir4.1 and Kir5.1. For clarifying the signals for this localization, specific sequence motifs of Kir4.1 were sought. In HEK293T cells, where Kir4.1 showed linear expression on the cell surface, disruption of the carboxyl-terminal PDZ-binding motif induced mostly clustered distribution but did not reduce whole-cell channel activity. Point mutation analysis revealed that serine377 in this motif was responsible for the surface vicinity expression. Disruption of the di-hydrophobic array of valine333/valine334 induced diffuse cytoplasmic distribution and diminished channel activity. Both valine333 and valine334 contributed to this effect. In contrast to the di-hydrophobic motifs of other membrane proteins that facilitate the sorting, valine333/valine334 supported the cell-surface retention. Because both the PDZ-binding and di-hydrophobic motifs participated in the basolateral expression of both Kir4.1 homomer and Kir5.1/Kir4.1 heteromer in MDCK cells, they are thought to be responsible for the localization of basolateral K+ channel in renal distal tubules.

Amino Acid Motifs↗

Cutting balloon angioplasty of resistant renal artery stenosis caused by fibromuscular dysplasia.

Balloon angioplasty is an established intervention to treat renovascular hypertension. Conventional balloon angioplasty is usually effective in cases of renovascular hypertension caused by fibromuscular dysplasia. In the present report, we describe two cases of renovascular hypertension caused by fibromuscular dysplasia in which stenotic lesions were resistant to conventional balloon angioplasty but were successfully managed by a cutting balloon. After cutting balloon angioplasty, systemic blood pressure was normalized in both patients, without the use of antihypertensive agents. Angioplasty by using a cutting balloon is a new therapeutic choice against renal artery stenosis that is resistant to dilation by a conventional balloon.

Adolescent↗

Plasma renin activity revealed renal artery stenosis concealed by aneurysms.

We describe a case of renovascular hypertension with renal artery stenosis concealed by aneurysms. Arteriography demonstrated no apparent renal artery stenosis, but did reveal aneurysms on the left renal artery. Captopril-loaded renoscintigraphy could not detect disturbed renal perfusion. High basal and exaggerated plasma renin activity after captopril administration were the only clues indicating renovascular hypertension. A reduction of the systemic blood pressure and normalized plasma renin activity after resection of the aneurysms confirmed preoperative renovascular hypertension. Fibromuscular dysplasia was an underlying cause of the arterial deformity. In cases of hypertension accompanied by renal artery aneurysms, the captopril-challenge test can be a useful tool to detect renal artery stenosis concealed by the aneurysms.

Adult↗

Predictors of undiagnosed renal artery stenosis among Japanese patients with risk factors of atherosclerosis.

Atherosclerotic renal artery stenosis (ARAS) is a significant cause of end stage renal dysfunction (ESRD) among the elderly. Although early detection of ARAS and induction of adequate treatment could reduce the incidence of ESRD, there have been few reports about parameters predictive of ARAS among Japanese. In this study, we investigated the clinical indicators that predict ARAS among Japanese with risk factors of atherosclerosis (> 40 years of age plus hypertension, dyslipidemia or diabetes mellitus). After eliminating the patients who had already been diagnosed with renal artery stenosis, 202 patients were enrolled. The renal arteries of all 202 patients were evaluated by magnetic resonance arteriography (MRA), and the stenoses with > 50% reduction in diameter at the ostium of the renal artery were defined as ARAS. MRA detected ARAS in 42 patients (31 hemilateral and 11 bilateral). Between the patients with and without ARAS there was no significant difference in gender distribution, detection of abdominal vascular bruits or smoking habit. The prevalences of diabetic, hypertensive and cerebrovascular comorbidity were also not significantly different. The mean blood pressure, body mass index and total serum cholesterol values were similar between the two groups. However, age, pulse pressure, serum uric acid, serum creatinine, amount of urinary protein, and coronary artery comorbidity were significantly higher, while estimated creatinine clearance was significantly lower in the patients with ARAS than in those without ARAS. A high prevalence of hypertensive retinopathy was also noted among patients with ARAS. Multivariate analysis revealed that older age and renal impairment were independent predictors of ARAS in Japanese patients with atherosclerotic risk factors.

Aged↗

Renal artery dissection after angiographic evaluation of lower extremities.

We describe a case of renovascular hypertension that was caused by renal artery dissection after an angiographic evaluation of the lower extremities. Retention of contrast medium in the affected kidney even 1 day after the procedure caused us to suspect renal artery dissection. Magnetic resonance angiography revealed irregular streaks in the lumen of the affected artery, a sign of dissection. Treatment by a transluminal angioplasty with stent insertion improved renal function and reduced systemic blood pressure with normalization of plasma renin activity. In patients whose systemic blood pressure increases suddenly after any conceivable physical traction on the abdominal aorta, evaluation of the renal arteries should be considered. Appropriate endovascular treatment can preserve renal function and reduce systemic blood pressure.

Aged↗