Regulatory Aspects of Cell and Gene Therapy Products: The Japanese Perspective

Regulations for regenerative medicine for human use, such as cell and gene therapy (CGT), have evolved in accordance with advancements in clinical experience, scientific knowledge, and social acceptance of these technologies. In November 2014, two acts, "The Act on the Safety of Regenerative Medicine" (ASRM) and the "Pharmaceuticals, Medical Devices, and Other Therapeutic Products Act" (PMD Act), came into effect in Japan. The responsibilities of medical institutions in ensuring the safety and transparency of such medical technologies are described under ASRM. The PMD Act provides the option of a new scheme for obtaining conditional and time-limited approval for CGT products. Overall, research and development on CGT products, especially gene therapy products, is progressing. New legislative frameworks have been designed to promote the timely development of new technologies and safe and effective CGT products for Japanese patients.

[Points to Consider for Continuous Manufacturing of Biotechnological Drug Products]

Continuous Manufacturing is a manufacturing method in which raw materials enter the manufacturing process continuously, and products are discharged continuously throughout the duration of the process including multiple unit operations. Continuous Manufacturing includes various options: Those with all stages of processing from charging raw materials to discharging final products that are continuous, and those with only certain parts of the manufacturing process that are continuous. It can be introduced in an appropriate range in consideration of the characteristics of products, manufacturing processes, robustness of processes, etc. Continuous Manufacturing is expected to have the following advantages: A wide range of manufacturing scales are available by adjusting the continuous operation time of the process; it is possible to use the same manufacturing equipment from the development stage to commercial production, eliminating the need to change to large scale manufacturing equipment; and it is possible to reduce the equipment installation area (footprint). While Continuous Manufacturing can be a major manufacturing technique of the pharmaceutical industry in the future, official documents such as guidelines for Continuous Manufacturing are limited. In particular, no official documents such as guidelines specialized in manufacturing of biotechnological drug products have been issued yet. In Japan Agency for Medical Research and Development (AMED) research project, we summarized the key points to consider for investigation of the control strategy for Continuous Manufacturing of biotechnological products as a document. In this paper, we introduce the document.

WHO informal consultation on revision of guidelines on evaluation of similar biotherapeutic products, virtual meeting, 30 June – 2 July 2021

The WHO informal consultation was held to promote the revision of WHO guidelines on evaluation of similar biotherapeutic products (SBPs) adopted by the Expert Committee on Biological Standardization (ECBS) in 2009. It was agreed in the past consultations that the evaluation principles in the guidelines are still valid, but a review was recommended to provide more clarity and case-by-case flexibility. The opportunity was therefore taken to review the experience and identify areas where the current guidance could be more permissive without compromising its basic principles, and where additional explanation could be provided regarding the possibility of reducing the amount of data needed for regulatory approval. The meeting participants applauded the leading role taken by the WHO in providing a much-needed streamlined approach for development and evaluation of SBPs which will provide efficient and cost-effective product development and increase patient access to treatments. It was recognized that the principles as currently described in the draft WHO guidelines are based on sound science and experience gained over the last fifteen years of biosimilar approvals. However, since these guidelines when finalised will constitute the global standard for biosimilar evaluation and assist national regulatory authorities in establishing revised guidance and regulatory practice in this complex area, it was felt that further revision and clarity on certain perspectives in specific areas was necessary to dispel uncertainties arising in the current revised version. This report describes the principles in the draft guidelines, including topics discussed and consensus reached.

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WHO guidelines serve as a basis for the development of national regulatory framework for biosimilars.

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Revision of guidelines is to provide more flexibility and clarification on data required for regulatory approval.

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Revised guidelines would contribute to improving consistency on regulatory decision and patient access to treatments.

Identification of Potent In Vivo Autotaxin Inhibitors that Bind to Both Hydrophobic Pockets and Channels in the Catalytic Domain

Autotaxin (ATX, also known as ENPP2) is a predominant lysophosphatidic acid (LPA)-producing enzyme in the body, and LPA regulates various physiological functions, such as angiogenesis and wound healing, as well as pathological functions, including proliferation, metastasis, and fibrosis, via specific LPA receptors. Therefore, the ATX-LPA axis is a promising therapeutic target for dozens of diseases, including cancers, pulmonary and liver fibroses, and neuropathic pain. Previous structural studies revealed that the catalytic domain of ATX has a hydrophobic pocket and a hydrophobic channel; these serve to recognize the substrate, lysophosphatidylcholine (LPC), and deliver generated LPA to LPA receptors on the plasma membrane. Most reported ATX inhibitors bind to either the hydrophobic pocket or the hydrophobic channel. Herein, we present a unique ATX inhibitor that binds mainly to the hydrophobic pocket and also partly to the hydrophobic channel, inhibiting ATX activity with high potency and selectivity in vitro and in vivo. Notably, our inhibitor can rescue the cardia bifida (two hearts) phenotype in ATX-overexpressing zebrafish embryos.

ENPP2 contributes to adipose tissue expansion and insulin resistance in diet-induced obesity

Body weight is tightly regulated by food intake and energy dissipation, and obesity is related to decreased energy expenditure (EE). Herein, we show that nucleotide pyrophosphatase/phosphodiesterase 2 (ENPP2, autotaxin) is an adipose-derived, secreted enzyme that controls adipose expansion, brown adipose tissue (BAT) function, and EE. In mice, Enpp2 was highly expressed in visceral white adipose tissue and BAT and is downregulated in hypertrophied adipocytes/adipose tissue. Enpp2(+/-) mice and adipocyte-specific Enpp2 knockout mice fed a high-fat diet showed smaller body weight gains and less insulin resistance than control mice fed the same diet. BAT was functionally more active and EE was increased in Enpp2-deficient mice. In humans, ENPP2 expression in subcutaneous fat and ENPP2 levels in serum were reduced in obese subjects. Taken together, our results establish ENPP2 as an adipose-derived, secreted enzyme that regulates adipose obesity and systemic metabolism. They also suggest ENPP2 could be a useful therapeutic target for the treatment of metabolic disease.

Screening and X-ray crystal structure-based optimization of autotaxin (ENPP2) inhibitors, using a newly developed fluorescence probe

Autotaxin (ATX), also known as ectonucleotide pyrophosphatase/phosphodiesterase 2 (ENPP2), was originally identified as a tumor cell autocrine motility factor and was found to be identical to plasma lysophospholipase D, which is the predominant contributor to lysophosphatidic acid (LPA) production from lysophospholipids. ATX is therefore considered to regulate the physiological and pathological roles of LPA, including angiogenesis, lymphocyte trafficking, tissue fibrosis, and cancer cell invasion and metastasis. Thus, it is a potential therapeutic target. Here, we first developed a sensitive and specific ATX fluorescence probe, TG-mTMP, and used it to screen ATX inhibitors in a large chemical library. This probe, which is superior to previously available probes FS-3 and CPF4 in terms of sensitivity or specificity, enabled us to identify several novel ATX inhibitor scaffolds. We solved the crystal structures of ATX complexes with the hit compounds at high resolution (1.75-1.95 Å) and used this information to guide optimization of the structure of a selected inhibitor. The optimized compounds, 3BoA and its derivatives, exhibited potent ATX-inhibitory activity both in vitro and in vivo. These inhibitors are expected to be useful tools to understand the roles of ATX in vitro and in vivo and may also be candidate anti-ATX therapeutic agents.

Gender difference in tooth autotransplantation with complete root formation: a retrospective survey

Gender-related risk factors in the survival of transplanted teeth with complete root formation have not yet been identified. The purpose of this study was to investigate gender differences in tooth autotransplantation at dental clinics. We asked participating dentists to provide information on transplantations they had undertaken from 1 January 1990 to 1931 December 2010. The data were screened to exclude patients who underwent more than one transplantation, smokers or those whose smoking habits were unknown, patients under 30 or who were 70 years old and over, cases where the transplanted teeth had incomplete root formation or multiple roots and those with fewer than 20 present teeth post-operation. We analysed 73 teeth of 73 males (mean age, 47.2 years) and 106 teeth of 106 females (mean age, 45.3 years) in this study. The cumulative survival rate and mean survival time were calculated using the Kaplan-Meier method. The cumulative survival rate for males was 88.3% at the 5-year mark, 64.8% at 10 years and 48.6% at 15 years; for females, it was 97.2% at the 5-year mark, 85.9% at 10 years and 85.9% at 15 years. A log-rank test indicated the difference between males and females to be significant (P = 0.011). There was also a significant difference in the main causes for the loss of transplanted teeth: males lost more transplanted teeth due to attachment loss than females (P < 0.05). These results indicate that males require more attention during the autotransplantation process, particularly at the stage of pre-operation evaluation and that of follow-up maintenance.

Constitutive lymphocyte transmigration across the basal lamina of high endothelial venules is regulated by the autotaxin/lysophosphatidic acid axis

Lymphocyte extravasation from the high endothelial venules (HEVs) of lymph nodes is crucial for the maintenance of immune homeostasis, but its molecular mechanism remains largely unknown. In this article, we report that lymphocyte transmigration across the basal lamina of the HEVs is regulated, at least in part, by autotaxin (ATX) and its end-product, lysophosphatidic acid (LPA). ATX is an HEV-associated ectoenzyme that produces LPA from lysophosphatidylcholine (LPC), which is abundant in the systemic circulation. In agreement with selective expression of ATX in HEVs, LPA was constitutively and specifically detected on HEVs. In vivo, inhibition of ATX impaired the lymphocyte extravasation from HEVs, inducing lymphocyte accumulation within the endothelial cells (ECs) and sub-EC compartment; this impairment was abrogated by LPA. In vitro, both LPA and LPC induced a marked increase in the motility of HEV ECs; LPC's effect was abrogated by ATX inhibition, whereas LPA's effect was abrogated by ATX/LPA receptor inhibition. In an in vitro transmigration assay, ATX inhibition impaired the release of lymphocytes that had migrated underneath HEV ECs, and these defects were abrogated by LPA. This effect of LPA was dependent on myosin II activity in the HEV ECs. Collectively, these results strongly suggest that HEV-associated ATX generates LPA locally; LPA, in turn, acts on HEV ECs to increase their motility, promoting dynamic lymphocyte-HEV interactions and subsequent lymphocyte transmigration across the basal lamina of HEVs at steady state.

Risk factors affecting third molar autotransplantation in males: a retrospective survey in dental clinics

The aim of this study was to investigate the risk factors affecting long-term prognosis of autotransplantation of third molars with complete root formation in males at dental clinics. Participating dentists were requested to provide information on transplantations they had undertaken from 1 January 1990 to 31 December 2010. Data on a total of 708 teeth from 637 patients were collected. After data screening and elimination, participants of this study consisted of 183 teeth of 171 males ranging from 20 to 72 years of age (mean age, 44·8 years). The cumulative survival rate was 86·0% at the 5-year mark, 59·1% at 10 years and 28·0% at 15 years. The mean survival time was 134·5 months, as calculated by the Kaplan-Meier method. Single factor analysis using the log-rank test showed that the following factors had significant influence (P < 0·05) on survival of transplanted teeth: periodontal disease as the reason for recipient site tooth extraction, fewer than 25 present teeth and Eichner index Groups B1 to C. Cox regression analysis examined five factors: age, smoking habit, recipient site extraction caused by periodontal disease, fewer than 25 present teeth and Eichner index. This analysis showed that two of these factors were significant: fewer than 25 present teeth was 2·63 (95% CI, 1·03-6·69) and recipient site extraction caused by periodontal disease was 3·80 (95% CI, 1·61-9·01). The results of this study suggest that long-term survival of transplanted teeth in males is influenced not only by oral bacterium but also by occlusal status.

Synthesis and biological evaluation of optically active Ki16425

An enantionselective synthesis of both enantiomers of Ki16425, which possesses selective LPA antagonistic activity, was achieved. The isoxazole core was constructed by a 1,3-dipolar cycloaddition of nitrile oxide with alkyne and condensation with the optically active α-phenethyl alcohol segment, which was prepared by an enantioselective reduction of arylmethylketone. Biological evaluation of both enantiomers of Ki16425 revealed that the (R)-isomer showed much higher antagonistic activity for LPA(1) and LPA(3) receptors.

Identification and biochemical characterization of a novel autotaxin isoform, ATXδ, with a four-amino acid deletion

Autotaxin (ATX) is lysophospholipase D, which converts lysophospholipids such as lysophosphatidylcholine (LPC) to lysophosphatidic acid (LPA), a bioactive lipid mediator with multiple biological roles. ATX is present in high concentrations in various biological fluids and is responsible for LPA production in these fluids. The plasma ATX level is altered in some patho-physiological conditions. Three splicing isoforms of ATX have been reported so far (ATXα, β and γ). In this study, we identified and characterized ATXδ, a novel alternative splice variant of ATX, which has a four-amino acid deletion in the L2 linker region of ATXβ. ATXδ was found to be the second major isoform following ATXβ and fully active. ATXβ and ATXδ showed similar divalent cation sensitivity and cell motility-stimulating activity. ATXβ and ATXδ are present in wide range of organism from fish to mammals. Among them, only ATXδ was found in Gallus gallus and Xenopus laevis, suggesting the indispensable role of the isoform. ATXδ was expressed in various human tissues with different expression patterns from that of ATXβ. These results show that ATXδ is a second major ATX isoform sharing similar biochemical characters with the major isoform, ATXβ, and is a potential biomarker.

Autotaxin regulates vascular development via multiple lysophosphatidic acid (LPA) receptors in zebrafish

Autotaxin (ATX) is a multifunctional ecto-type phosphodiesterase that converts lysophospholipids, such as lysophosphatidylcholine, to lysophosphatidic acid (LPA) by its lysophospholipase D activity. LPA is a lipid mediator with diverse biological functions, most of which are mediated by G protein-coupled receptors specific to LPA (LPA1-6). Recent studies on ATX knock-out mice revealed that ATX has an essential role in embryonic blood vessel formation. However, the underlying molecular mechanisms remain to be solved. A data base search revealed that ATX and LPA receptors are conserved in wide range of vertebrates from fishes to mammals. Here we analyzed zebrafish ATX (zATX) and LPA receptors both biochemically and functionally. zATX, like mammalian ATX, showed lysophospholipase D activity to produce LPA. In addition, all zebrafish LPA receptors except for LPA5a and LPA5b were found to respond to LPA. Knockdown of zATX in zebrafish embryos by injecting morpholino antisense oligonucleotides (MOs) specific to zATX caused abnormal blood vessel formation, which has not been observed in other morphant embryos or mutants with vascular defects reported previously. In ATX morphant embryos, the segmental arteries sprouted normally from the dorsal aorta but stalled in midcourse, resulting in aberrant vascular connection around the horizontal myoseptum. Similar vascular defects were not observed in embryos in which each single LPA receptor was attenuated by using MOs. Interestingly, similar vascular defects were observed when both LPA1 and LPA4 functions were attenuated by using MOs and/or a selective LPA receptor antagonist, Ki16425. These results demonstrate that the ATX-LPA-LPAR axis is a critical regulator of embryonic vascular development that is conserved in vertebrates.

Fluorescence probe for lysophospholipase C/NPP6 activity and a potent NPP6 inhibitor

Nucleotide pyrophosphatases/phosphodiesterases (NPPs) are ubiquitous membrane-associated or secreted ectoenzymes that have a role in regulating extracellular nucleotide and phospholipid metabolism. Among the members of the NPP family, NPP1 and -3 act on nucleotides such as ATP, while NPP2, -6, and -7 act on phospholipids such as lysophosphatidylcholine and sphingomyelin. NPP6, a recently characterized NPP family member, is a choline-specific glycerophosphodiester phosphodiesterase, but its functions remain to be analyzed, partly due to the lack of highly sensitive activity assay systems and practical inhibitors. Here we report synthesis of novel NPP6 fluorescence probes, TG-mPC and its analogues TG-mPC(3)C, TG-mPC(5)C, TG-mPENE, TG-mPEA, TG-mPhos, TG-mPA, TG-mPMe, and TG-mPPr. Among the seven NPPs, only NPP6 hydrolyzed TG-mPC, TG-mPC(3)C, and TG-mPENE. TG-mPC was hydrolyzed in the cell lysate from NPP6-transfected cells, but not control cells, showing that it is suitable for use in cell-based NPP6 assays. We also examined the usefulness of TG-mPC as a fluorescence imaging probe. We further applied TG-mPC to carry out high-throughput NPP6 inhibitor screening and found several NPP6-selective inhibitors in a library of about 80,000 compounds. Through structure-activity relationship (SAR) analysis, we identified a potent and selective NPP6 inhibitor with an IC(50) value of 0.21 μM. Our NPP6-selective fluorescence probe, TG-mPC, and the inhibitor are expected to be useful to elucidate the biological function of NPP6.

Serum autotaxin measurements in pregnant women: application for the differentiation of normal pregnancy and pregnancy-induced hypertension

BACKGROUND

The bioactive lipid lysophosphatidic acid (LPA) exerts multiple effects in the female reproductive system. Serum/plasma LPA is mainly produced by the lysophospholipase D activity of autotaxin (ATX). Previous studies have suggested that ATX has critical roles in cancer, reproduction, and vascular development. In the present study, we evaluated the usefulness of serum ATX measurements in pregnant women.

METHODS

We measured the serum ATX antigen levels in 32 normal pregnant women, 15 patients with pregnancy-induced hypertension (PIH), and 7 patients with preterm delivery using a recently developed automated enzyme immunoassay.

RESULTS

The serum ATX antigen levels in normal pregnant women were significantly higher than those in non-pregnant women (P<0.001). The serum ATX antigen levels in normal pregnant women were significantly and positively correlated with the gestational week (r=0.809, P<0.001). During the third trimester, the serum ATX antigen levels of the patients with PIH (3.299 ± 1.720 mg/l) were significantly lower than those of the normal pregnant women (4.915 ± 2.323 mg/l) (P=0.04).

CONCLUSIONS

The serum ATX antigen level increases with the progression of pregnancy. The serum ATX level may be a serological marker for the prediction of PIH.

Crystal structure of autotaxin and insight into GPCR activation by lipid mediators

Autotaxin (ATX, also known as Enpp2) is a secreted lysophospholipase D that hydrolyzes lysophosphatidylcholine to generate lysophosphatidic acid (LPA), a lipid mediator that activates G protein-coupled receptors to evoke various cellular responses. Here, we report the crystal structures of mouse ATX alone and in complex with LPAs with different acyl-chain lengths and saturations. These structures reveal that the multidomain architecture helps to maintain the structural rigidity of the lipid-binding pocket, which accommodates the respective LPA molecules in distinct conformations. They indicate that a loop region in the catalytic domain is a major determinant for the substrate specificity of the Enpp family enzymes. Furthermore, along with biochemical and biological data, these structures suggest that the produced LPAs are delivered from the active site to cognate G protein-coupled receptors through a hydrophobic channel.

Adiponectin suppresses tumorigenesis in Apc(Min)(/+) mice

Recent reports have shown that adiponectin has a suppressive effect on various types of malignancy. In order to clarify the role of adiponectin in colorectal carcinogenesis, we examined the effect of exogenous administration of adiponectin on intestinal polyp formation in C57BL/6J-Apc(Min)(/+) mice, which possess a point mutation in the Apc gene. And we found that adiponectin treatment significantly decreased the number of adenomatous polyps, especially polyps larger than 2mm in diameter, in the small intestine. Two major receptors for adiponectin, AdipoR1 and AdipoR2, were expressed in adenomatous polyps, and their expression levels were not altered by adiponectin injection. In conclusion, adiponectin suppresses the growth of intestinal adenomas in the Apc(Min)(/+) mice. Increasing the adiponectin level may be a new strategy for the prevention of colorectal cancer at an early step of carcinogenesis.

Involvement of the lysophosphatidic acid-generating enzyme autotaxin in lymphocyte-endothelial cell interactions

Autotaxin (ATX) is a secreted protein with lysophospholipase D activity that generates lysophosphatidic acid (LPA) from lysophosphatidylcholine. Here we report that functional ATX is selectively expressed in high endothelial venules (HEVs) of both lymph nodes and Peyer's patches. ATX expression was developmentally regulated and coincided with lymphocyte recruitment to the lymph nodes. In adults, ATX expression was independent of HEV-expressed chemokines such as CCL21 and CXCL13, innate immunity signals including those via TLR4 or MyD88, and of the extent of lymphocyte trafficking across the HEVs. ATX expression was induced in venules at sites of chronic inflammation. Receptors for the ATX enzyme product LPA were constitutively expressed in HEV endothelial cells (ECs). In vitro, LPA induced strong morphological changes in HEV ECs. Forced ATX expression caused cultured ECs to respond to lysophosphatidylcholine, up-regulating lymphocyte binding to the ECs in a LPA receptor-dependent manner under both static and flow conditions. Although in vivo depletion of circulating ATX did not affect lymphocyte trafficking into the lymph nodes, we surmise, based on the above data, that ATX expressed by HEVs acts on HEVs in situ to facilitate lymphocyte binding to ECs and that ATX in the general circulation does not play a major role in this process. Tissue-specific inactivation of ATX will verify this hypothesis in future studies of its mechanism of action.

Serum autotaxin measurement in haematological malignancies: a promising marker for follicular lymphoma

Autotaxin (ATX) is a tumour cell motility-stimulating factor originally isolated from melanoma cell supernatants. ATX is identical to lysophospholipase D, which produces a bioactive lipid mediator, lysophosphatidic acid (LPA), from lysophosphatidylcholine. ATX is overexpressed in various malignancies, including Hodgkin lymphoma, and ATX may stimulate tumour progression via LPA production. The present study measured the serum ATX antigen levels in patients with haematological malignancies using a recently developed automated enzyme immunoassay. The serum ATX antigen levels in patients with B-cell neoplasms, especially follicular lymphoma (FL), were higher than those in healthy subjects. Serum ATX antigen levels in FL patients were associated with tumour burden and changed in parallel with the patients' clinical courses. The serum ATX antigen levels were little affected by inflammation, unlike the soluble interleukin-2 receptor and beta2-microglobulin levels. As expected, the plasma LPA levels in FL patients were correlated with the serum ATX antigen levels. Given that leukaemic tumour cells from FL patients expressed ATX, the shedding of ATX from lymphoma cells probably leads to the elevation of serum ATX antigen levels. Our results suggest that the serum ATX antigen level may be a promising and novel marker for FL.

Two pathways for lysophosphatidic acid production

Lysophosphatidic acid (LPA, 1- or 2-acyl-sn-glycerol 3-phosphate) is a simple phospholipid but displays an intriguing cell biology that is mediated via interactions with G protein-coupled seven transmembrane receptors (GPCRs). So far, five GPCRs, designated LPA1-5, and, more recently, two additional GPCRs, GPR87 and P2Y5, have been identified as receptors for LPA. These LPA receptors can be classified into two families, the EDG and P2Y families, depending on their primary structures. Recent studies on gene targeting mice and family diseases of these receptors revealed that LPA is involved in both pathological and physiological states including brain development (LPA1), neuropathy pain (LPA1), lung fibrosis (LPA1), renal fibrosis (LPA1) protection against radiation-induced intestinal injury (LPA2), implantation (LPA3) and hair growth (P2Y5). LPA is produced both in cells and biological fluids, where multiple synthetic reactions occur. There are at least two pathways for LPA production. In serum or plasma, LPA is predominantly produced by a plasma enzyme called autotaxin (ATX). ATX is a multifunctional ectoenzyme and is involved in many patho-physiological conditions such as cancer, neuropathy pain, lymphocyte tracking in lymph nodes, obesity, diabetes and embryonic blood vessel formation. LPA is also produced from phosphatidic acid (PA) by its deacylation catalyzed by phospholipase A (PLA)-type enzymes. However, the physiological roles of this pathway as well as the enzymes involved remained to be solved. A number of phospholipase A1 and A2 isozymes could be involved in this pathway. One PA-selective PLA1 called mPA-PLA1alpha/LIPH is specifically expressed in hair follicles, where it has a critical role in hair growth by producing LPA through a novel LPA receptor called P2Y5.

Validation of an autotaxin enzyme immunoassay in human serum samples and its application to hypoalbuminemia differentiation

BACKGROUND

Autotaxin (ATX), a tumor cell motility-stimulating factor, regulates the blood concentrations of lysophosphatidic acid (LPA), an important and multi-functional bioactive lipid, through its lysophospholipase D activity (lysoPLD). The introduction of ATX measurements into clinical laboratory testing is urgently needed.

METHODS

Anti-human ATX monoclonal antibodies were produced by immunization of recombinant human ATX expressed in a baculovirus system. An immunoassay for the quantitative determination of ATX was established, and human serum samples were assayed.

RESULTS

The within-run and between-run precision, interference, detection limit, and linearity studies were satisfactory. The central 95 percentile reference interval for the serum ATX antigen concentration in healthy subjects was 0.468-1.134 mg/l (n=120) and was strongly correlated with the serum lysoPLD activity. The ATX concentration was significantly (p<0.001) higher in women (0.625-1.323 mg/l) than in men (0.438-0.914 mg/l). The serum ATX concentrations were increased in patients with chronic liver diseases and decreased in postoperative prostate cancer patients but were not altered in nephrosis patients. Thus, serum ATX antigen concentrations could be used to discriminate these hypoalbuminemia conditions.

CONCLUSIONS

The present ATX antigen assay may be useful for clinical laboratory testing.

Both plasma lysophosphatidic acid and serum autotaxin levels are increased in chronic hepatitis C

OBJECTIVES

Recent accumulating evidence indicates that lysophosphatidic acid (LPA) is a lipid mediator, abundantly present in blood, with a wide range of biologic actions including the regulation of proliferation and contraction in liver cells. Although it is speculated that LPA might play a role in pathophysiologic processes in vivo, not only its role but also even a possible alteration in its blood concentration under specific diseases is essentially unknown. Autotaxin (ATX), originally purified as an autocrine motility factor for melanoma cells, was revealed to be a key enzyme in LPA synthesis. We determined LPA and ATX levels in the blood of patients with liver disease.

METHODS

ATX activity was measured by determining choline with the substrate of lysophosphatidylcholine, and the LPA level by an enzymatic cycling method in 41 patients with chronic hepatitis C.

RESULTS

The serum ATX activity and plasma LPA level were significantly increased in patients, and were correlated positively with serum hyaluronic acid, and negatively with platelets, albumin, and prothrombin time. The plasma LPA level was strongly correlated with serum ATX activity. There were significant correlations between the histologic stage of fibrosis and both the serum ATX activity and plasma LPA level.

CONCLUSIONS

The serum ATX activity and plasma LPA level are increased in chronic hepatitis C in association with liver fibrosis. Our study may provide the first evidence showing a significant increase of both ATX and LPA in the blood under a specific disease.

Cyclic phosphatidic acid is produced by autotaxin in blood

Cyclic phosphatidic acid (cPA), an analog of lysophosphatidic acid (LPA), was previously identified in human serum. Although cPA possesses distinct physiological activities not elicited by LPA, its biochemical origins have scarcely been studied. In the present study, we assayed cPA formation from lysophosphatidylcholine in fetal bovine serum and found significant activity of transphosphatidylation that generated cPA. The cPA-producing enzyme was purified from fetal bovine serum using five chromatographic steps yielding a 100-kDa protein with cPA biosynthetic activity. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry of its tryptic peptides revealed that the enzyme shared identical fragments with human autotaxin, a serum lysophospholipase D that produces LPA. Western blot analysis demonstrated that the 100-kDa protein was specifically recognized by an anti-human autotaxin antibody. Moreover, recombinant rat autotaxin was found to generate cPA in addition to LPA. No significant cPA- or LPA-producing activity was detected in autotaxin-depleted serum from bovine or human prepared by immunoprecipitation with an anti-autotaxin monoclonal antibody. These results indicate that the generation of cPA and LPA in serum is mainly attributed to autotaxin.

Autotaxin stabilizes blood vessels and is required for embryonic vasculature by producing lysophosphatidic acid

Autotaxin (ATX) is a cancer-associated motogen that has multiple biological activities in vitro through the production of bioactive small lipids, lysophosphatidic acid (LPA). ATX and LPA are abundantly present in circulating blood. However, their roles in circulation remain to be solved. To uncover the physiological role of ATX we analyzed ATX knock-out mice. In ATX-null embryos, early blood vessels appeared to form properly, but they failed to develop into mature vessels. As a result ATX-null mice are lethal around embryonic day 10.5. The phenotype is much more severe than those of LPA receptor knock-out mice reported so far. In cultured allantois explants, neither ATX nor LPA was angiogenic. However, both of them helped to maintain preformed vessels by preventing disassembly of the vessels that was not antagonized by Ki16425, an LPA receptor antagonist. In serum from heterozygous mice both lysophospholipase D activity and LPA level were about half of those from wild-type mice, showing that ATX is responsible for the bulk of LPA production in serum. The present study revealed a previously unassigned role of ATX in stabilizing vessels through novel LPA signaling pathways.

Autotaxin is overexpressed in glioblastoma multiforme and contributes to cell motility of glioblastoma by converting lysophosphatidylcholine to lysophosphatidic acid

Autotaxin (ATX) is a multifunctional phosphodiesterase originally isolated from melanoma cells as a potent cell motility-stimulating factor. ATX is identical to lysophospholipase D, which produces a bioactive phospholipid, lysophosphatidic acid (LPA), from lysophosphatidylcholine (LPC). Although enhanced expression of ATX in various tumor tissues has been repeatedly demonstrated, and thus, ATX is implicated in progression of tumor, the precise role of ATX expressed by tumor cells was unclear. In this study, we found that ATX is highly expressed in glioblastoma multiforme (GBM), the most malignant glioma due to its high infiltration into the normal brain parenchyma, but not in tissues from other brain tumors. In addition, LPA1, an LPA receptor responsible for LPA-driven cell motility, is predominantly expressed in GBM. One of the glioblastomas that showed the highest ATX expression (SNB-78), as well as ATX-stable transfectants, showed LPA1-dependent cell migration in response to LPA in both Boyden chamber and wound healing assays. Interestingly these ATX-expressing cells also showed chemotactic response to LPC. In addition, knockdown of the ATX level using small interfering RNA technique in SNB-78 cells suppressed their migratory response to LPC. These results suggest that the autocrine production of LPA by cancer cell-derived ATX and exogenously supplied LPC contribute to the invasiveness of cancer cells and that LPA1, ATX, and LPC-producing enzymes are potential targets for cancer therapy, including GBM.

Influence of serum from rats with fulminant hepatic failure on hepatocytes in a bioartificial liver system

Fulminant hepatic failure (FHF) is a life-threatening condition marked by many excessively increased unmetabolized toxins and growth factors. Recently developed bioartificial liver (BAL) systems containing hepatocytes can be used to treat patients with FHF However, the behavior of these hepatocytes on exposure to FHF serum in vitro remains unclear. In the present study, we used FHF rat models and the sera from these rats (i.e., FHF serum) contained elevated inflammatory cytokines (TNF-alpha, IL-1beta, and IL-6), HGF, and TGF-beta1. In addition, 1x10(8) hepatocytes were harvested from the livers of inbred rats and incubated with microcarrier beads. Four hours later, the hepatocyte-coated beads were inoculated into a hollow-fiber module (=BAL system). FHF serum or normal control serum circulated for 6 hours through the BAL system. Expressions of mRNA for albumin, GST A1, CYP 1A2, OTC and c-fos were investigated by RT-PCR, and PCNA staining was performed before and after perfusion. The expressions of albumin, GST A1, and CYP 1A2 mRNAs were markedly decreased, whereas those of OTC and c-fos were modestly decreased. PCNA positive cells were low and showed no difference between FHF and normal serum-exposed hepatocytes. In conclusion, the exposure of hepatocytes to hypercytokinemia, including inflammatory cytokines and positive and negative growth factors, caused a loss in liver specific functions. This environment also failed to facilitate hepatocyte regeneration.

Influence of the duration of the second stage of labor on fetal pH levels and oxidative status in uncomplicated pregnancies

OBJECTIVE

We examined the influence of the duration of the second stage of labor on fetal pH levels and oxidative status in uncomplicated pregnancies.

METHODS

Blood gases in the umbilical artery and serum uric acid and plasma malondialdehyde levels in the umbilical venous blood were measured at delivery in uncomplicated nulliparous women whose second stage of labor was 0-60 min (n = 38), 61-120 min (n = 14) and 121-180 min (n = 6).

RESULTS

There were no significant differences in the measured variables between the three groups.

CONCLUSION

The duration of the second stage of labor up to 3 h does not influence lipid peroxidation in the fetoplacental circulation in uncomplicated pregnancies.

Identification of extracapsular invasion of the metastatic lymph nodes as a useful prognostic sign in patients with resectable colorectal cancer

PURPOSE

The present study was undertaken to evaluate whether the microscopic patterns of distribution and extracapsular invasion of cancer cells in the regional lymph nodes were linked to the survival rates for patients with advanced colorectal cancer who undergo a curative surgical resection.

METHODS

Two hundred ninety-six surgically resected metastatic lymph nodes from 84 patients with node-positive colorectal cancer were microscopically examined. The distribution of cancer cells in the lymph nodes were grouped into two types: type A (> or =50 percent cancer) and type B (<50 percent cancer). The extracapsular invasion of cancer cells in the nodes were divided into three subgroups: pattern X (no evidence of cancer cell invasion into the adjacent tissue); pattern Y (less than five cancer cells were seen in the adjacent tissue); and pattern Z (more than five cancer cells invaded the adjacent tissue). The patients, based on these microscopic manifestations of metastatic patterns in the nodes, were divided into three groups: Group 1, patients with pattern X nodal metastases only; Group 2, patients with pattern Y and pattern (X + Y) nodal metastases; and Group 3, patients with pattern Z, pattern (X + Z), pattern (Y + Z), and pattern (X + Y + Z) nodal metastases.

RESULTS

The survival rates and disease-free survival rates for patients with metastatic lymph nodes showing an extracapsular invasion pattern (Groups 2 and 3) were significantly worse than those for patients with metastatic nodes showing no extracapsular invasion pattern only (Group 1; P < 0.01). There was no significant difference for the above-cited survival rates among the groups classified according to the Dukes and TNM systems.

CONCLUSIONS

It is the thesis of this article that the identification of extracapsular invasion of the metastatic lymph nodes can be taken as a useful prognostic sign in patients with resectable colorectal cancer.

A second primary esophageal cancer developing 7 years after chemoradiotherapy for advanced esophageal cancer

We report a rare case of advanced carcinoma and a second primary carcinoma of the esophagus, both of which were successfully cured by chemotherapy and operation at different times. In 1991, a 38-year-old Japanese man was diagnosed with advanced esophageal cancer, which was unresectable because of the bronchial invasion of the tumor. He was given chemotherapy with cisplatin (CDDP), combined with radiotherapy. During a 4-year follow-up, neither regrowth of the primary tumor nor distant metastasis occurred. In 1995, esophagoscopy demonstrated a lugol-unstained region located 3 cm distal from the area of radiation to the primary lesion shown by esophagography. Histological examination of a biopsy specimen showed the mucosa to be normal. Nevertheless, yearly surveillance by endoscopy and histological examinations showed that the mucosa of the esophagus gradually began to demonstrate mild dysplasia, followed by severe dysplasia; in 1998, a diagnosis of squamous cell carcinoma was made. Esophagectomy with lymph node dissection was performed. Microscopic examination revealed that there had been pathologic complete response for the original advanced esophageal cancer.

Changes in liver regenerative factors in a case of living-related liver transplantation

Liver regeneration in a patient with fulminant hepatic failure (FHF) who underwent living-related partial liver transplantation (LRLT) was investigated regarding hepatic growth factors. The patient was a 16-yr-old Japanese male who developed severe subacute FHF. LRLT was performed using an extended left lobe of the ABO matched patient's mother. In the recipient, the pre-transplant levels of both plasma hepatocyte growth factor (HGF) and transforming growth factor (TGF)-beta were extremely high and rapidly decreased following the liver replacement. The liver volume evaluated using a CAT scan increased 195% after 2 wk in graft liver and 110% after 2 wk in the hepatectomized donor. The explanted liver (FHF liver), the liver from donor (normal liver), and the graft liver [the 3rd post-transplant day (POD 3)] were all investigated immunohistochemically. FHF liver: No liver regeneration was observed [proliferative cell nuclear antigen (PCNA) labeling index (L.I.): 0%]. In the liver, both HGF in the hepatocytes and c-met on the membrane of the hepatocytes were positive. TGF-beta was positive in the hepatocytes and no apoptosis was detected by the TUNEL method. Donor liver (POD 0): Few PCNA stained hepatocytes were detected. No HGF was detected but c-met was clearly detected on the cell membrane of the hepatocytes. Neither TGF-beta nor apoptosis was detected. Graft liver (POD 3): The PCNA L.I. was conspicuous at 40%. HGF was positive in non-parenchymal cells and c-met was positive in the cytoplasm of the hepatocytes. TGF-beta was negative while apoptosis was positive in the zone 3 hepatocytes. In conclusion, these findings suggested that the liver of the patient with FHF did not respond to liver regenerative stimulus, in part, through involvement of inhibitor TGF-beta. On POD 3, the transplanted graft was in a vigorous regenerative status in comparison to that in the hepatectomized donor. The HGF/c-met system is thought to be involved in the mechanism of regeneration. Intrahepatic apoptosis was detected in the graft on the 3rd post-transplant day probably due to transient ischemia in the liver, which was not related to the Fas/Fas-ligand system.

Characteristics of monochorionic-diamniotic growth-retarded twins during the third trimester

The goal of this study was to assess the characteristics of monochorionic-diamniotic (MD) growth-retarded twin infants with twin-twin transfusion syndrome (TTTS) compared with those without TTTS during the third trimester. Retrospective analyses of the growth patterns and amniotic fluid volumes were performed on 5 MD twin pregnancies in which one or both twins showed growth retardation with TTTS, and the results weve compared with those without TTTS. Eighty-three percent of growth-retarded twin infants without TTTS in MD twin gestation showed an asymmetric growth pattern, while all TTTS cases showed a symmetric pattern (p < 0.05). Polyhydramnios of the co-twin was found in 80% of TTTS cases, while no polyhydramnios was found in patients without TTTS (p < 0.05). Assessment of growth patterns and amniotic fluid volume may be useful to exclude the possibility of TTTS in MD growth-retarded twin pregnancies during the third trimester.

Tetanus after a resection for a gangrenous perforated small intestine: report of a case

We report herein the case of a 75-year-old man who developed severe tetanus 24 h after the resection of a gangrenous perforated small intestine. It seemed that the tetanus was caused by a spillage of the intestinal contents harboring Clostridium tetani; however, this was not identified by a culture. The diagnosis of tetanus was made only when opisthotonus in this patient became evident and normal tetanus treatment proved to be successful.

[A case of partial Addison's disease activated with the administration of rifampicin (RFP)]

The patient was a 76 year-old female with tuberculous tendonitis, treated with anti-tuberculous drugs including rifampicin (RFP). About two weeks after the start of RFP, she noticed general malaise and started vomiting, and the laboratory data showed severe hyponatremia. Because of mild liver dysfunction, RFP was discontinued and her symptoms gradually improved. Abdominal X-ray and CT showed swellings and calcifications of adrenal glands bilaterally. Serum ACTH level was high and cortisole, 17-OHCS, and 17-KS levels were normal. Her response to rapid ACTH stimulation was blunted significantly. After another trial of RFP, she started to vomit and complain general malaise again. We diagnosed her as partial Addison's disease and administered hydrocortisone with RFP. After this treatment her improvement was rapid. It has been known that RFP causes induction of enzymes in hepatic microsomes which increase the catabolism of glucocorticoids. To avoid the risk of adrenal insufficiency, patients with insufficient adrenal hormone reserve should receive compensatory hydrocortisone while they are taking RFP.

Successful surgical treatment of gastric cancer with a tumor thrombus in the portal and splenic veins: report of a case

We report herein the case of a 70-year-old woman with histologically confirmed gastric Borrmann type 3 cancer in the posterior wall of the fundus in whom computed tomography demonstrated a dilated portal trunk and splenic vein containing a low-density mass, but no evidence of liver metastases. The venous phase of a superior mesenteric arteriogram subsequently showed occlusion of the main portal vein with venous collaterals. At surgery, a tumor thrombus was noted to extend from the short gastric vein to the portal vein via the splenic vein. Thus, an extensive gastric resection together with removal of the tumor thrombus from the veins was performed, and successful results were achieved.

[Diffuse aspiration bronchiolitis in an elderly woman]

A 74-year-old woman was admitted to the hospital because of persistent nocturnal coughing and abnormal shadows on chest x-ray films. The films showed cavities in the right upper lobe and small nodular shadows in the right upper, lower, and left upper lung fields. Examination of a specimen obtained by transbronchial lung biopsy showed nonspecific inflammatory changes. An open-lung biopsy was done. Histopathological examination showed evidence of diffuse aspiration bronchiolitis and actinomyces. Actinomyces is a member of the endogenous flora of the oral mucous membranes. Our diagnosis was diffuse aspiration bronchiolitis caused by micro-aspiration of oro-pharyngeal secretions during sleep.

CT of neural plexus invasion in common bile duct carcinoma

PURPOSE

Our purpose was to analyze the CT findings of neural plexus invasion in common bile duct carcinoma.

METHOD

We studied 16 patients with common bile duct carcinoma who underwent surgery. Of these, neural invasion was seen in 10 patients. CT findings were retrospectively reviewed and correlated with the surgical and pathological findings.

RESULTS

Irregular masses adjacent to the medial aspect of the uncinate process were observed in 4 of 14 patients with distal common bile duct carcinoma. These lesions extended medially and showed contiguity with the superior mesenteric artery and/or celiac axis, corresponding to neural plexus invasion with desmoplastic change. Increased attenuation of the fat between the common bile duct and the proper hepatic artery was seen in two of two patients with proximal common bile duct carcinoma, associated with neural plexus invasion in the hepatoduodenal ligament.

CONCLUSION

The location and spread of neural plexus invasion in common bile duct carcinoma are characteristic and can be diagnosed by CT.

Gastric cancer: evaluation of triphasic spiral CT and radiologic-pathologic correlation

PURPOSE

The purpose of this study was to evaluate the utility of triphasic spiral CT with water-filling method in the preoperative T staging of gastric cancer.

METHOD

We performed triphasic spiral CT in 108 patients with gastric cancer (53 with early and 55 with advanced gastric cancer). The CT findings were prospectively analyzed and correlated with the histopathologic findings. Spiral CT scans were assessed for the layered pattern of the normal gastric wall, the detectability of tumor, the enhancing pattern of the tumor, and the depth of tumor invasion.

RESULTS

The layered pattern of the normal gastric wall was clearly demonstrated in the arterial-dominant or parenchymal phase. All 12 early cancers detected with spiral CT were most clearly depicted in the arterial-dominant or parenchymal phase. On the other hand, 15 (28%) of 54 advanced cancers were most clearly depicted in the equilibrium phase due to the gradual enhancement from the inner mucosal side of the tumor. Most of these tumors were scirrhous type tumor containing abundant fibrous tissue stroma. The accuracy of spiral CT for tumor detection and T staging was 98 and 82%, respectively, in advanced gastric cancer and 23 and 15%, respectively, in early gastric cancer.

CONCLUSION

Spiral CT with triphasic scan technique improved the accuracy of estimating the depth of tumor invasion in advanced gastric cancer.

Seasonal variation in sweating responses of older and younger men

Eight older (60-65 years) and six younger (20-25 years) men were exposed to a standard heat stress for 60 min in summer, autumn, winter, and spring. The test consisted of placing the lower legs and feet in a 42 degrees C water bath while sitting in constant environmental conditions (30 degrees C and 45% relative humidity). The increase of rectal temperature (delta Tre) was significantly greater (P < 0.05) in autumn, winter, and spring than in summer for the older group, but significantly greater only in winter than in summer for the younger group (P < 0.05). The delta Tre was greater for the older group in all seasons, but of significance only in autumn and spring (P < 0.01). There were no significant season-related differences for metabolic heat production (M) and mean skin temperature (Tsk) during the heat test in the respective groups, although the M and Tsk were lower for the older group in all seasons (P < 0.01). In the older group total body sweating rate (msw) divided by delta Tre (total msw/delta Tre) decreased from summer to winter (P < 0.02) and did not differ between winter and spring, whereas total msw/delta Tre in the younger group increased in spring after decreasing from autumn to winter (P < 0.03). The variations of the value, local sweating rate on the back and thigh divided by delta Tre (back msw/delta Tre and thigh msw/delta Tre), were similar to those of the total msw/delta Tre in each group, except for back msw/delta Tre in the younger group, which did not increase from winter to spring.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenomatous hyperplasia in the vicinity of small hepatocellular carcinoma

The nodular lesions seen in the noncancerous areas of the 80 consecutively resected small hepatocellular carcinoma associated with cirrhosis were pathomorphologically studied. A total of 51 nodular lesions were found, and they were classified into the following four groups: large regenerative nodule (30 nodules), adenomatous hyperplasia (12 nodules), atypical adenomatous hyperplasia (4 nodules) and adenomatous hyperplasia containing cancerous foci (5 nodules). Grossly, all large regenerative nodules were well demarcated, but some of the adenomatous hyperplasia group were vaguely nodular. Atypical adenomatous hyperplasia and adenomatous hyperplasia containing cancerous foci accounted for 43% of the adenomatous hyperplasia group found in the vicinity of the 16 resected hepatocellular carcinoma (20%) out of 80 cases. The mean size (+/- S.D.) of the adenomatous hyperplasias containing cancerous foci, 15.8 +/- 2.2 mm, was significantly larger than 10.1 +/- 2.6 mm of the adenomatous hyperplasias p less than 0.01). All adenomatous hyperplasias containing cancerous foci and 75% of the atypical adenomatous hyperplasias demonstrated a marked fatty change, but none of the large regenerative nodules were accompanied by any fatty changes. This study demonstrated the morphological transition from adenomatous hyperplasia to hepatocellular carcinoma that was suggestive of multistep hepatocarcinogenesis. As a result, it is predicted that approximately 20% of all hepatocellular carcinomas may have the potential for being of multicentric origin and that approximately 40% of adenomatous hyperplasias may undergo malignant transformation, but it is difficult to estimate the exact number of incidences. The presence of varying degrees of fatty change may be one of the significant morphological markers for a malignant transformation from adenomatous hyperplasia to hepatocellular carcinoma.(ABSTRACT TRUNCATED AT 250 WORDS)

Studies on thromboplastic and fibrinolytic activities of valvular tissue in rheumatic valvular disease

While rheumatic valvular disease (RVD) is known to develop subsequent to rheumatic carditis, we examined whether in addition to the inflammatory and repair process, thromboplastic and fibrinolytic activities of the valvular tissue play a contributory role in the pathogenesis of RVD. Both activities were higher in resected valves from RVD cases than in the controls. Tissue thromboplastin was localized in the valvular endothelium and the subendothelial connective tissue. Tissue fibrinolytic activity was prevalent in the small blood vessels of RVD valves, while it was lower on the surface of RVD valves than in the controls. High thromboplastic and low fibrinolytic activity in the surface layer of RVD valves may accelerate the deposition of thrombi, thereby inducing valvular thickening.