Mediolateral intercalation in planarians revealed by grafting experiments.

We investigated how planarians organize their left-right axis by using ectopic grafting. Planarians have three body axes: anteroposterior (A-P), dorsoventral (D-V), and left-right (L-R). When a small piece is implanted into an ectopic region along the A-P and D-V axes, intercalary structures are always formed to compensate for positional gaps. There are two hypotheses regarding L-R axis formation in this organism: first, that the left and right sides of the animal may be recognized as different parts, and L-R intercalation can induce midline structures (asymmetry hypothesis); second, that both sides may have symmetrical positional values, and mediolateral (M-L) intercalation creates positional values along the L-R axis (symmetry hypothesis). We performed ectopic grafting experiments in the head region of the planarian, Dugesia japonica, to examine these hypotheses. A left lateral fragment containing a left auricle was implanted into the medial region of the host. Ectopic structures were always formed only on the left side of the graft, where lateral tissues abutted onto the medial tissues. However, no morphologic change was induced on the right side of the graft, where left-sided tissues faced onto right-sided tissues. Molecular marker analyses indicated that ectopic structures formed on the left side of the graft were induced by M-L intercalation, supporting the "symmetry hypothesis." When the midline tissues were implanted into a lateral region, they induced a complete ectopic head, demonstrating that M-L intercalation may be sufficient to establish the L-R axis in planarians.     

Assessment of donor liver steatosis: pathologist or automated software?

Steatosis in donor liver biopsy specimens has been shown to correlate with graft dysfunction after orthotopic liver transplantation. This 2-part (laboratory pilot, clinical retrospective) study compared the traditional interpretation of steatosis by a pathologist with an automated measurement determined by an image analysis system. In our pilot study, Sprague-Dawley rats were studied prospectively by feeding them a choline-deficient diet for up to 7 days. In our clinical group, data from 49 consecutive recipients of cadaveric liver transplantation were reviewed retrospectively. In both studies, the percentages of microvesicular fat, macrovesicular fat, and total fat content within liver biopsy specimens were determined by an automated image analysis software program and a pathologist using the same set of slides. The association between fat content of the donor liver and patient survival and graft survival, along with levels of aspartate aminotransferase, alanine aminotransferase, prothrombin time, and total bilirubin after transplantation, were also examined in the clinical study. A direct correlation was observed between levels of macrovesicular fat determined by a pathologist and the automated software using livers from rats fed a choline-deficient diet and livers from deceased donors. A significant association was observed between macrovesicular fat content in the donor liver biopsy and graft survival by both techniques. We conclude that an image analysis system can be used to automate the determination of fat content in liver biopsy specimens, and that its findings correlate with both the visual interpretation by a pathologist and graft survival. Further study is needed to determine the role of an automated technique in the evaluation of donor livers for transplantation.     

Comparison of various bone marrow fractions in the ability to participate in vascular remodeling after mechanical injury

In contrast to conventional assumption, recent reports propose the possibility that hematopoietic stem cells (HSCs) may have broader potential to differentiate into various cell types. Here, we tested the pluripotency of HSCs by comparing vascular lesions induced by mechanical injury after bone marrow reconstitution with total bone marrow (TBM) cells, c-Kit+ Sca-1+ Lin- (KSL) cells, or a single HSC cell (Tip-SP CD34-KSL cell, CD34- c-Kit+ Sca-1+ Lin- cell with the strongest dye-efflux activity) harboring green fluorescent protein (GFP). The lesions contained a significant number of GFP-positive cells in the TBM and KSL groups, whereas GFP-positive cells were rarely detected in the HSC group. These results suggest that transdifferentiation of a highly purified HSC seems to be a rare event, if it occurs at all, whereas bone marrow cells including the KSL fraction can give rise to vascular cells that substantially contribute to repair or lesion formation after mechanical injury.     

The National Health Plan 2030: Its Purpose and Directions of Development

The National Health Plan 2030 (HP2030) started to be prepared in 2017 and was completed and announced in December 2020. This study presents an overview of how it was established, the major changes in policies, its purpose, and future directions. This study analyzed the steps taken in the past 4 years to establish HP2030 and reviewed major issues at the international and governmental levels based on an evaluation of HP2020 and its content. HP2030 establishes 6 divisions and 28 topic areas, and it will continue to expand investments in health with a total budget of 2.5 trillion Korean won. It also established goals to enhance health equity for the first time, with the goal of calculating healthy life expectancy in a way that reflects the circumstances of Korea and reducing the gap in income and healthy life expectancy between regions. The establishment of HP2030 is significant in that it constitutes a sustainable long-term plan with sufficient preparation, contains policy measures that everyone participates in and makes together, and works towards improvements in universal health standards and health equity. With the announcement of HP2030, which includes goals and directions of the national health policy for the next 10 years, it will be necessary to further strengthen collaboration with relevant ministries, local governments, and agencies in various fields to concretize support for prevention-centered health management as a national task and to develop a health-friendly environment that considers health in all policy areas.     

Intercellular Interactions of an Adipogenic CXCL12-Expressing Stromal Cell Subset in Murine Bone Marrow

Bone marrow houses a multifunctional stromal cell population expressing C-X-C motif chemokine ligand 12 (CXCL12), termed CXCL12-abundant reticular (CAR) cells, that regulates osteogenesis and adipogenesis. The quiescent pre-adipocyte-like subset of CXCL12⁺ stromal cells (“Adipo-CAR” cells) is localized to sinusoidal surfaces and particularly enriched for hematopoiesis-supporting cytokines. However, detailed characteristics of these CXCL12⁺ pre-adipocyte-like stromal cells and how they contribute to marrow adipogenesis remain largely unknown. Here we highlight CXCL12-dependent physical coupling with hematopoietic cells as a potential mechanism regulating the adipogenic potential of CXCL12⁺ stromal cells. Single-cell computational analyses of RNA velocity and cell signaling reveal that Adipo-CAR cells exuberantly communicate with hematopoietic cells through CXCL12-CXCR4 ligand-receptor interactions but do not interconvert with Osteo-CAR cells. Consistent with this computational prediction, a substantial fraction of Cxcl12-creER⁺ pre-adipocyte-like cells intertwines with hematopoietic cells in vivo and in single-cell preparation in a protease-sensitive manner. Deletion of CXCL12 in these cells using Col2a1-cre leads to a reduction of stromal-hematopoietic coupling and extensive marrow adipogenesis in adult bone marrow, which appears to involve direct conversion of CXCL12⁺ cells to lipid-laden marrow adipocytes without altering mesenchymal progenitor cell fates. Therefore, these findings suggest that CXCL12⁺ pre-adipocyte-like marrow stromal cells prevent their premature differentiation by maintaining physical coupling with hematopoietic cells in a CXCL12-dependent manner, highlighting a possible cell-non-autonomous mechanism that regulates marrow adipogenesis. © 2021 American Society for Bone and Mineral Research (ASBMR).     

Metabolism and distribution in the rat of peak E substance,a constituent inl-tryptophan product implicated in eosinophilia-myalgia syndrome

Peak E substance, 1,1-ethylidenebis[tryptophan], a contaminant found inl-tryptophan tablets, has been suggested as a causative agent for eosinophilia-myalgia syndrome (EMS). Peak E substance (50 mg/kg) was administered perorally to Wistar rats to determine its metabolism and distribution. A purification procedure using Bond Elut C₈ cartridges followed by HPLC was developed for the determination of peak E substance. The plasma concentration of peak E substance was 136 ng/ml at 1 h, and urinary excretion was 717 ng at 5 h and 10342 ng for 5–24 h, showing slow excretion of peak E substance into urine. The amount of peak E substance in the contents of the large intestine at 5 h, however, was 3136 g, much greater than urinary excretion for 24 h, indicating considerable transfer of peak E substance to large intestine without decomposition by gastric fluid in the stomach. We have detected for the first time not only the occurrence of peak E substance in plasma and urine, but also 1-methyl-tetrahydro--carboline-3-carboxylic acid (MTCA) in blood and organs of rats treated with peak E substance, thereby suggesting MTCA as one of the the metabolites of peak E substance. The amount of MTCA in the contents of the large intestine as well as in urine of rats treated with peak E substance was significantly greater than inl-tryptophantreated rats (50 mg/kg p.o.), demonstrating that MTCA was more readily produced from peak E substance than froml-tryptophan. Finally, we propose acetaldehydeinduced production of MTCA from peak E substance.     

Accumulation of 1-methyl-tetrahydro-Β-carboline-3-carboxylic acid in blood and organs of rat. A possible causative substance of eosinophilia-myalgia syndrome associated with ingestion ofl-tryptophan

1-Methyl-tetrahydro--carboline-3-carboxylic acid (MTCA) may cause eosinophilia-myalgia syndrome (EMS) associated with ingestion ofl-tryptophan. The distribution and excretion of MTCA were studied in rats which had received perorally a single 1.6 mg/kg dose of MTCA. MTCA concentrations in blood, kidney, liver, brain, heart, spleen, lung and gastrocnemius muscle were measured by HPLC combined with fluorometric detection. The concentration of MTCA in each organ reached a maximum at 1 h and then gradually declined. However, a significant level of MTCA still remained at 5 h, when 52% of ingested MTCA remained in the contents of the large intestine. Twenty-nine percent of the ingested MTCA was excreted in urine over the course of 24 h. A higher dose (10 mg/kg) of MTCA resulted in significant elevations in the concentrations and amounts of MTCA in the various organs. In addition, chronic treatment with a 10 mg/kg dose of MTCA for 6 weeks further increased the concentrations and amounts of MTCA in each organ. However, no histological changes were observed in any of the organs after chronic treatment. This is the first report which demonstrates accumulation of MTCA in the blood and various organs, including muscle, of rats.     

Opsonic function and concentration of human serum ficolin/P35.

Collectins, C-type (Ca2+-dependent) animal lectins with both collagenous and carbohydrate recognition domains, function as opsonins against pathogens. We previously described an N-acetylglucosamine (GlcNAc)-binding lectin (ficolin/P35) with a collagen- and a fibrinogen-like sequence present in human serum. In this report we show that ficolin/P35 can serve as an opsonin and enhance the clearance of pathogens having surface GlcNAc. Ficolin/P35 bound to an Ra chemotype strain of Salmonella typhimurium (TV119) which has an exposed GlcNAc at the non-reducing termini of the polysaccharide. On the other hand, ficolin/P35 did not bind to LT2, a smooth type strain of S. typhimurium with additional O-polysaccharides covering GlcNAc. Ficolin/P35 enhanced the uptake of TV119 by monocytes or polymorphonuclear leukocytes but had no opsonic activity towards LT2. These results suggest that, like collectins, ficolin/P35 is a collagenous lectin which has a role in innate immunity against certain pathogenic organisms by acting as an opsonin. We prepared monoclonal antibodies against ficolin/P35 and developed an enzyme-linked immunosorbent assay (ELISA) for measuring ficolin/P35 concentrations in humans. The mean serum concentration of ficolin/P35 from 130 normal individuals was estimated to be 13.7 microg/ml.     

Risk factors for hepatocellular carcinoma at baseline and 1 year after initiation of nucleos(t)ide analog therapy for chronic hepatitis B

Nucleos(t)ide analogs (NAs) cannot completely suppress the risk of hepatocellular carcinoma (HCC) in patients with chronic hepatitis B (CHB). This study aimed to identify the risk factors for HCC development in naïve CHB patients treated with current NA. Patients receiving NA (n = 905) were recruited retrospectively from the 17 hospitals of the Japanese Red Cross Liver Study Group. All treatment-naïve patients had been receiving current NA continuously for more than 1 year until the end of the follow-up. We analyzed the accuracy of predictive risk score using the area under receiver operating characteristic curve. The albumin–bilirubin (ALBI) score was significantly improved by NA therapy (−0.171 ± 0.396; p < 0.001 at Week 48). A total of 72 (8.0%) patients developed HCC over a median follow-up of 6.2 (1.03–15.7) years. An independent predictive factor of HCC development was older age, cirrhosis, lower platelet counts at baseline and ALBI score, and alpha-fetoprotein (AFP) at 1 year after NA therapy according to multivariate analysis. The accuracy was assessed using the PAGE-B, mPAGE-B, aMAP, APA-B, and REAL-B scores that included these factors. Discrimination was generally acceptable for these models. aMAP and REAL-B demonstrated high discrimination with 0.866/0.862 and 0.833/0.859 for 3- and 5-year prediction from the status of 1 year after NA therapy, respectively. Baseline age and platelet count, as well as ALBI and AFP one year after NA, were useful for stratifying carcinogenesis risk. The aMAP and REAL-B scores were validated with high accuracy in Japanese CHB patients.