Cells sorted off hiPSC-derived kidney organoids coupled with immortalized cells reliably model the proximal tubule.

Of late, numerous microphysiological systems have been employed to model the renal proximal tubule. Yet there is lack of research on refining the functions of the proximal tubule epithelial layer-selective filtration and reabsorption. In this report, pseudo proximal tubule cells extracted from human-induced pluripotent stem cell-derived kidney organoids are combined and cultured with immortalized proximal tubule cells. It is shown that the cocultured tissue is an impervious epithelium that offers improved levels of certain transporters, extracellular matrix proteins collagen and laminin, and superior glucose transport and P-glycoprotein activity. mRNA expression levels higher than those obtained from each cell type were detected, suggesting an anomalous synergistic crosstalk between the two. Alongside, the improvements in morphological characteristics and performance of the immortalized proximal tubule tissue layer exposed, upon maturation, to human umbilical vein endothelial cells are thoroughly quantified and compared. Glucose and albumin reabsorption, as well as xenobiotic efflux rates through P-glycoprotein were all improved. The data presented abreast highlight the advantages of the cocultured epithelial layer and the non-iPSC-based bilayer. The in vitro models presented herein can be helpful in personalized nephrotoxicity studies.

The actual status of drug prices and adjustment factors for drug price calculation: an analysis of ultra-orphan drug development in Japan.

BACKGROUND: Extremely high prices facilitate drug development for ultra-rare diseases (ultra-orphan drugs). However, various problems arise in terms of healthcare financing and fairness, and the status of ultra-orphan drug pricing remains ambiguous. In this study, we investigated ultra-orphan drug prices in Japan relative to that of other drugs. We examined the relationship between annual expected drug prices and expected sales, and the expected number of patients, for 393 drugs containing new active ingredients for therapeutic use that were listed on the National Health Insurance drug price list in Japan between April 16, 2010 and August 26, 2020. In addition, we compared prices, the drug price calculation method, and price calculation adjustment factors for ultra-orphan and other drugs. RESULTS: Drug prices tended to increase as the expected number of patients to whom the drug was administered decreased; however, this trend diminished when the expected number of patients was less than 1000. On the other hand, the expected sales tended to decrease as the number of expected patients decreased, and this tendency was reinforced when the expected number of patients was less than 1000. The cost accounting method tended to be used for the price calculation of ultra-orphan drugs, but there were no price differences based on the drug price calculation method. Regarding the price calculation adjustment factors, the premium for usefulness tended to be higher for ultra-orphan drugs. The premium for marketability was higher for non-orphan drugs but did not differ from that for orphan drugs, except for ultra-orphan drugs. CONCLUSIONS: The status of drug prices and expected sales differed beyond a threshold of 1000 expected patients, indicating that recovering the development cost for ultra-orphan drugs is difficult. In addition, the higher premium for usefulness for ultra-orphan drugs reflects the largely unmet need of the associated diseases. Scarcity among orphan drugs is not considered for marketability, highlighting the need for a new framework to promote the development of ultra-orphan drugs.

Evaluation of Macaca radiata as a non-human primate model of Dengue virus infection.

Dengue virus (DENV) causes a wide range of illnesses in humans, including dengue fever and dengue haemorrhagic fever. Current animal models of DENV infection are limited for understanding infectious diseases in humans. Bonnet monkeys (Macaca radiata), a type of Old World monkey, have been used to study experimental and natural infections by flaviviruses, but Old World monkeys have not yet been used as DENV infection models. In this study, the replication levels of several DENV strains were evaluated using peripheral blood mononuclear cells. Our findings indicated that DENV-4 09-48 strain, isolated from a traveller returning from India in 2009, was a highly replicative virus. Three bonnet monkeys were infected with 09-48 strain and antibody responses were assessed. DENV nonstructural protein 1 antigen was detected and high viraemia was observed. These results indicated that bonnet monkeys and 09-48 strain could be used as a reliable primate model for the study of DENV.

Association between reflux esophagitis and/or hiatus hernia and gastric mucosal atrophy level in Japan.

BACKGROUND AND AIMS: The mechanisms involved in reflux esophagitis (RE) are mainly esophageal motor dysfunction and abnormal esophageal acid exposure. Therefore the extent of gastric mucosal atrophy (GMA), which is related to gastric acid secretion, is an important factor in the development of RE. The aim of this study was to evaluate the prevalence of RE and hiatus hernia (HH) according to level of GMA. METHODS: A total of 1897 prospective, consecutive endoscopic examinations were performed by the same endoscopist to investigate the prevalence of RE and HH in patients with closed or open-type GMA. The patients were divided into four age groups: under 44, 45-54, 55-64 and over 65 years. RESULTS: The prevalence of RE and HH in patients with closed-type GMA was significantly higher than that of open-type GMA in the 45-54, 55-64 and over 65 age groups. In patients with open-type GMA, the prevalence of RE in each age group was similar at 5.0-7.4%, and the prevalence of HH in the over 65 age group was significantly higher than that of the 55-64 age group. In patients with closed-type GMA, the prevalence of RE and HH in the over 65 age group was significantly higher than that of other age groups. CONCLUSIONS: The existence of closed-type GMA and age over 65 years were important factors in the development of RE and HH.

Transient lower esophageal sphincter relaxations (TLESRs) are the major mechanism of gastroesophageal reflux but are not the cause of reflux disease.

In healthy subjects, the rate of acid reflux during transient lower esophageal sphincter relaxations (TLESRs) is more frequent at the proximal margin of the LES. In this study, we investigated the hypothesis that the rate of acid reflux at the proximal margin of LES during TLESRs is similar in reflux disease to that in healthy subjects. Concurrent esophageal manometry and pH monitoring were performed in the sitting position for 3 hr after a standard meal in 10 patients with reflux disease and 10 age-matched healthy controls. The rate of TLESRs in patients with reflux disease (5.0/hr [3.3-6.7]; median [interquartile range]) was similar to that of controls (4.5/hr [3.7-5.7]). The incidence of acid reflux 7 cm above the LES during TLESRs in patients (48.1% [27.2-71.4%]) was significantly higher than that in controls (10.9% [0.0-18.8%]) but there was no difference 2 cm above the LES (75.0 [69.2-87.5] vs. 74.3 [55.5-90.0%]). The rate of TLESRs and the incidence of acid reflux during TLESRs are not increased in reflux disease. These findings, therefore, indicate that reflux disease is not a disorder of TLESRs and relates more to the proximal extent of the refluxate.

[Pathophysiology of GERD: mechanisms of gastroesophageal reflux and prolonged esophageal acid exposure time].

GERD is characterized by excessive esophageal acid exposure time. This suggests that either the rate of gastroesophageal reflux (GER) is higher and/or that the esophageal acid clearance time is longer. Transient LES relaxation (TLESR) is the single most common mechanism underlying GER in both normal subjects and patients with GERD. Whether or not the rate of TLESRs is higher in patients with GERD remains unclear. It is in the sitting or upright position that acid reflux mainly occurs, however, there seems to be no difference in the rate of TLESRs between both groups. The rate of TLESRs accompanied by acid reflux has been consistently shown to be significantly greater in patients with GERD than in normal subjects. Other mechanisms of reflux in patients with severe GERD are a hypotensive LES and ineffective esophageal motility which is found in severe GERD and which impairs bolus clearance of acid and thus increases acid contact time with the esophageal mucosa.

The minimum pressure of the lower esophageal sphincter, determined by the rapid pull-through method, is an index of severe reflux esophagitis.

BACKGROUND: Because of the wide overlap between the groups, patients with reflux esophagitis (RE) cannot be distinguished from healthy subjects by basal lower esophageal sphincter (LES) pressure. The LES has radial asymmetry, with maximum pressure on the left side. It has been noted that one directional LES pressure, determined using the rapid pull-through (RPT) method, in most patients with severe RE is very low, compared with that in healthy subjects. The aim of this study was to examine whether or not the minimum value of four directional LES pressures could become an index of RE by the RPT method. METHODS: Thirty patients with severe RE (grade C or D of the Los Angeles classification) were compared with 30 patients with mild RE (grade A or B) and 30 healthy subjects of comparable age and sex. LES pressure was measured by the RPT method, with the subject in the supine position. The catheter was withdrawn manually at a rate of 10 mm/s during suspended respiration at the end-expiratory phase after 5-min rest accommodation. LES pressure, with reference to the intragastric fundic pressure, was recorded by three consecutive RPTs, and 12 LES pressures were obtained for each subject. RESULTS: Minimum LES pressure, mean LES pressure, and maximum LES pressure were calculated from the 12 LES pressures. Wide overlaps in the mean and maximum LES pressures between healthy subjects and patients with mild or severe RE occurred; however, the overlap of minimum LES pressure between these groups was clearly less than that for the mean and maximum LES pressures. If it is accepted that more than the tenth percentile of the minimum LES pressure in healthy subjects is the cutoff value for healthy subjects, the sensitivity was 93.3% and the specificity for severe RE was 93.3%. CONCLUSIONS: This finding would suggest that the minimum LES pressure determined by the RPT method is an index of severe RE.

Esophageal motility in Japanese patients with Barrett's esophagus.

BACKGROUND: The prevalence of gastroesophageal reflux disease has been increasing in Japan as it has in Western countries, but Barrett's esophagus (BE) is less common in Japan than in Western countries. The aim of this study, therefore, was to investigate esophageal motility and clinical characteristics in Japanese patients with BE. METHODS: Ten patients with BE were compared with ten patients with mild reflux esophagitis (RE), ten patients with severe RE, and ten healthy subjects of comparable age and sex. The prevalence of Helicobacter pylori was investigated in the patients with BE. The intraluminal microtransducer method was used to test for esophageal motility. Basal lower esophageal sphincter (LES) pressure was assessed by the rapid pull-through method. The esophageal wave after ten repeated 5-ml water swallowings at 30-s intervals was measured at 3, 8, 13, and 18 cm above the LES. RESULTS: The basal LES pressure, the amplitude of the esophageal wave at 3 and 8 cm above the LES, and the frequency of primary peristalsis in the severe RE group and BE group were significantly lower than the values in the healthy subjects and the mild RE group. The amplitude of the esophageal wave 13 cm above the LES in the BE group was significantly lower than that in the healthy subjects and the mild RE group. There was no difference between the severe RE group and the BE group in the basal LES pressure and the amplitude of the esophageal wave. The frequency of primary peristalsis in the BE group, however, was significantly lower than that in the severe RE group. Nine of the ten patients with BE were H. pylori-negative. CONCLUSIONS: Our conclusions are that esophageal dysmotility in Japanese patients with BE represents an advanced stage of severe RE, and that most Japanese patients with BE are H. pylori-negative.