Dysesthesia is an unpleasant abnormal sensation, often accompanied by pain, paresthesia (abnormal sensation), and numbness (decrease or loss of sensation). Dysesthesia has been associated with various conditions, although its underlying mechanisms are largely unknown. This study assessed the roles of transient receptor potential ankyrin 1 (TRPA1) in dysesthesia by utilizing three animal models of dysesthesia characterized by reductions in blood flow to the skin: a transient hindlimb ischemia/reperfusion model, characterized by spontaneous licking and tactile hypoesthesia of the ischemic hindpaw; a streptozotocin-induced diabetic neuropathy model in mice, characterized by cold hypersensitivity, which is likely parallel to the reduced skin blood flow of the hindpaw; and a hindlimb ischemia model. TRPA1 inhibition or deficiency blocked spontaneous licking in the transient hindlimb ischemia/reperfusion model and cold hypersensitivity in the diabetic mouse model mice. Consistent with these results, the nocifensive behaviors induced by intraplantar injection of a TRPA1 agonist were enhanced in the diabetic neuropathy and hindlimb ischemia models. Hypoxia enhanced H2O2-induced TRPA1 responses in human TRPA1-expressing cells and cultured mouse dorsal root ganglion neurons, with this hypoxia-induced TRPA1 sensitization to H2O2 being associated with hypoxia-induced inhibition of the hydroxylation of prolyl hydroxylases. These results suggest that dysesthesia following blood flow reduction is caused by the activation of TRPA1 sensitized by hypoxia and that hypoxia-induced TRPA1 sensitization plays a pivotal role in painful dysesthesia induced by peripheral blood flow reduction.
Matrix metalloproteinases (MMPs) regulate various cellular functions, such as motility, invasion, differentiation, and apoptosis. Precise in vivo quantification of MMPs in disease can provide beneficial information for both basic and clinical research studies. To this end, various types of probes have been developed for imaging MMPs in vivo. In this review, representative MMP-targeted probes, such as binding probes and activatable probes, are outlined, including highlights of our own research. In addition, strategies for the development of probes that apply “theranostics,” a concept that integrates therapy and diagnostics, are elucidated with reference to [18F]IPFP, a new probe developed in our laboratory. [18F]IPFP was prepared by iodination of a known MMP inhibitor to enhance its affinity and labeled with the compact prosthetic agent 4-nitrophenyl 2-[18F]fluoropropionate ([18F]NFP) for MMP-targeted positron-emission tomography (PET) and other therapeutic properties. IPFP demonstrated high inhibitory activity toward MMP-12 (IC50 value=1.5 nM). Radioactivity accumulation in the lungs 90 min after administration of [18F]IPFP was 4-fold higher in chronic obstructive pulmonary disease (COPD) mice overexpressing MMPs compared with normal mice. Ex vivo PET confirmed the radioactivity distribution in tissues, and autoradiography analysis demonstrated accumulation differences between COPD and normal mice. Consequently, [18F]IPFP showed potent inhibitory activities against MMPs and suitable pharmacokinetics for imaging pulmonary disease. Thus, [18F]IPFP is a promising theranostic probe for pulmonary disease and is expected to be applied to various other MMP-related diseases. Strategies for MMP probe development introduced in this review are anticipated to lead to the development of superior imaging probes in the future.
The development of serious lung diseases, such as pulmonary fibrosis, is associated with several drugs. A recent study has shown that the epithelial-mesenchymal transition (EMT) plays an essential role in the development of pulmonary fibrosis. However, the mechanisms underlying drug-induced EMT in alveolar epithelial cells have not been characterized. The present study showed that methotrexate (MTX), a drug known to cause lung injury, induced EMT-like phenotypic changes in an A549 cell model of the alveolar epithelium. We also found that the transforming growth factor (TGF)-β1-mediated signaling pathway was associated with MTX-induced EMT. In addition, our results showed that certain secreted factors and microRNAs, a class of small noncoding RNAs, may be involved in MTX-induced EMT. The effects of COA-Cl, a novel synthetic small molecule, on TGF-β1-induced EMT were evaluated to determine the therapeutic potential of COA-Cl against drug-induced lung injury. COA-Cl significantly suppressed TGF-β1-induced EMT-like phenotypic changes, as evidenced by the inhibition of EMT-related transcription factors. Furthermore, MTX-induced EMT was completely suppressed by co-treatment with folic acid. Thus, these compounds may be promising therapeutic agents against drug-induced lung injury. In conclusion, the present study elucidated mechanisms underlying drug-induced EMT and highlighted a potential novel therapeutic approach to drug-induced lung diseases.
Despite a continuous increase in R&D spending on potential new medicines, the success rate of drug development has not improved. The pharmaceutical industry is now facing a major challenge. As a college student who was studying pharmaceutical sciences in Japan, I became passionate about developing a new technology that would allow us to efficiently discover novel drug targets and selective chemical ligands for these targets. This realization encouraged me to join the PhD program at The Scripps Research Institute (TSRI) in 2013, where I carried out thesis research focusing on ligand discovery for poorly characterized metabolic enzymes for lipid signaling under the guidance of Prof. Benjamin Cravatt. TSRI is a unique place where researchers with different backgrounds collaborate frequently to conduct highly interdisciplinary research with the goal of translating cutting-edge research into clinical use. In this column, I am sharing my experiences as a PhD student at TSRI. I hope this column will be a useful source of information for younger students considering going abroad for a PhD degree.
After completing my doctoral training, I joined the Ronald Davis Laboratory at The Scripps Research Institute, Florida. At Scripps, I extended my research and worked to understand the mechanisms of age-related memory impairment. Three and a half years in Florida passed very quickly while I worked with a multi-national multi-cultural team of scientists. Since returning to Japan, I now lead my own research team. My research experience abroad helped me to expand my scope of research, and allowed me to combine the fields of aging and neurosciences to discover solutions for many newly emerging challenges to human health. Beyond the experience I gained from my research, working with researchers from different cultures and with different values broadened my horizons. One of my best memories while working in the USA was to enjoy going to the beach near my laboratory while waiting in between my experiments. Looking back, it was great to have so much time to myself to reflect on my challenging research topic, while also having a chance to make so many new friends. Having friends to share in and cherish each other's successes, or to discuss our research or a wide range of topics—even after returning to Japan—is indeed a great wealth I now possess as a result of having studied abroad.
Studying abroad may prove an attractive opportunity for young Japanese scientists, as it would allow them to broaden their perspectives regarding occupational diversity as a scientist. This is the first observation I made after studying abroad at the University of Oxford for two and a half years as a postdoctoral fellow. Many young scientists in the UK have got occupations not only in academia or in manufacturing industries, but also in various other business fields. Their occupational diversity seems to be considerably wider than that found among young Japanese scientists. The second feature I observed was related to my new lifestyle in the UK, which included the practice of research. It was notably different from my experiences in Japan, and it made me reconsider how to conduct my research in a more efficient manner. During my stay in the UK, I was able to identify the significance of spending time in a different culture by avoiding contact with Japanese culture as much as I could. In this essay, I introduce the details of my process of departing for the UK and my life in Oxford; it is my hope that this information will be useful for young Japanese scientists in contemplating their life plans.
After finishing my Ph.D., I had the opportunity to work as a postdoc in the Division of Redox Regulation (laboratory of Tobias Dick) at the German Cancer Research Center in Heidelberg for almost three years. Although cultural differences between Japan and Germany made my time in Germany hectic, the experience expanded my worldview as well as my research expertise. Here I would like to share my experience in conducting research abroad and give my opinion about its significance. I hope that this symposium review will be helpful to students interested in researching abroad and will give them a positive impression and encouragement.
My dream was to study abroad someday. Just after earning my Ph.D., I married and soon had children. I have had a busy life since then, balancing work with childcare, and thus had almost given up on my dream. How lucky—a chance suddenly came to me! I had an opportunity to study at the University of Geneva. In my case, the issue to overcome for this study abroad was how my family would be dealt with. After consulting with my family, I decided to take two daughters with me to Switzerland. Although I had a bit of a hard time, I managed to lead a fruitful life thanks to a good environment for bringing up children, as well as the support I received from a number of people. I realize that had I been alone, I would have finished my research faster. On the other hand, life with my children gave me the opportunity to gain some precious experiences, for example, the chance to interact with other parents at school as well as with neighbors and my local community. These experiences would not have been possible if my daughters had not been with me. Their presence, and the added interactions this brought, not only forced me to better understand the local and traditional cultures, but also enhanced my communication skills beyond the academic setting. I think there are many benefits to studying abroad with children. In this paper, I would like to describe my experiences for female researchers.
The author has described two new functions of endothelial cells for efficient delivery of drugs to tissues. First, it was indicated that tight junction (TJ)-associated protein, claudin-1, exerts potent paracellular barrier function in cultured mouse lung microvascular endothelial cells (LMECs). This barrier was instantly and reversibly opened by reduction of TJ proteins expression via histamine H1 and H2 receptors. Histamine was biosynthesized by l-histidine decarboxylase from uptaken l-histidine, and biotransformed by type B of monoamine oxidase, suggesting that histamine concentration is controlled in rat brain MECs (BMECs) and LMECs. Moreover, uptake of l-histidine into BMECs and LMECs markedly increased with addition of ZnSO4. Second, it was suggested that drug-metabolizing enzymes such as CYP and flavin-containing monooxygenase exist in vascular endothelial cells exposed to blood and to aerobic conditions. These cells have the same ability to metabolize drugs as hepatocytes, demonstrating that vascular endothelial cells are a metabolic barrier against tissue transfer of drugs. From these results, it was suggested that reversible opening of TJ and selective inhibition of drug metabolism in vascular endothelial cells may be efficient delivery strategies of drugs to tissues. Finally, I hope that this research will lead to development of new drugs and possible re-evaluation of discontinued drugs.
Since the first report in 2003, bisphosphonate-related osteonecrosis of the jaw (BRONJ) has been increasing, without effective clinical strategies. Osteoporosis is common in elderly women, and bisphosphonates (BPs) are typical and widely used anti-osteoporotic or anti-bone-resorptive drugs. BRONJ is now a serious concern in dentistry. As BPs are pyrophosphate analogues and bind strongly to bone hydroxyapatite, and the P-C-P structure of BPs is non-hydrolysable, they accumulate in bones upon repeated administration. During bone-resorption, BPs are taken into osteoclasts and exhibit cytotoxicity, producing a long-lasting anti-bone-resorptive effect. BPs are divided into nitrogen-containing BPs (N-BPs) and non-nitrogen-containing BPs (non-N-BPs). N-BPs have far stronger anti-bone-resorptive effects than non-N-BPs, and BRONJ is caused by N-BPs. Our murine experiments have revealed the following. N-BPs, but not non-N-BPs, exhibit direct and potent inflammatory/necrotic effects on soft-tissues. These effects are augmented by lipopolysaccharide (the inflammatory component of bacterial cell-walls) and the accumulation of N-BPs in jawbones is augmented by inflammation. N-BPs are taken into soft-tissue cells via phosphate-transporters, while the non-N-BPs etidronate and clodronate inhibit this transportation. Etidronate, but not clodronate, has the effect of expelling N-BPs that have accumulated in bones. Moreover, etidronate and clodronate each have an analgesic effect, while clodronate has an anti-inflammatory effect via inhibition of phosphate-transporters. These findings suggest that BRONJ may be induced by phosphate-transporter-mediated and infection-promoted mechanisms, and that etidronate and clodronate may be useful for preventing and treating BRONJ. Our clinical trials support etidronate being useful for treating BRONJ, although additional clinical trials of etidronate and clodronate are needed.
In patients being treated with bisphosphonates (anti-bone-resorptive drugs), bisphosphonate-related osteonecrosis of the jaw (BRONJ) is a serious concern. The authors demonstrate that nitrogen-containing bisphosphonates (N-BPs) are transported into soft-tissue cells via phosphate transporters and therein exhibit cytotoxicity, while non-nitrogen-containing bisphosphonates (non-N-BPs) inhibit this transportation. Based on results from animal and clinical studies, they propose that the non-N-BPs etidronate and clodronate may be useful for preventing and/or treating BRONJ. They also demonstrate that N-BP-induced toxicity is augmented by infection.
We previously reported the association of the estimated glomerular filtration rate (eGFRcreat) calculated from the serum creatinine level (S-Cr) measured using the Jaffe method with the GFR (eGFRcys) estimated from the serum cystatin C level (CysC). However, few studies have compared the eGFRcreat using the enzymatic method with the eGFRcys. It is unclear whether there are differences in the results of renal function assessment. The purpose of this study was to compare the eGFRcreat calculated from the S-Cr with the eGFRcys calculated from the CysC in patients in whom the S-Cr and CysC were simultaneously measured using the enzymatic method, examine the correlations of respective parameters, and clarify physiological factors involved in differences among the parameters. The subjects were 1334 patients treated in 5 institutions. The mean values and correlation coefficient were statistically analyzed using Student's t-test and Pearson's test, respectively. Influential factors between formulae were analyzed using multiple regression analysis. The mean eGFRcreat was 67.0 mL/min/1.73 m2, being significantly higher than the mean eGFRcys (63.2). Multiple regression analysis showed that factors influencing differences in the S-Cr and CysC included the sex, age, serum albumin, and blood urea nitrogen BUN/S-Cr. Furthermore, factors involved in the overestimation of the eGFRcreat in comparison with the eGFRcys included the serum albumin and BUN/S-Cr. The differences between the eGFRcreat calculated from the S-Cr and eGFRcys were less marked than when adopting the Jaffe method in our previous study. However, the eGFRcreat were higher than the eGFRcys in patients with malnutrition or dehydration.
Non-steroidal anti-inflammatory drugs (NSAIDs) are widely known as painkillers. The analgesic action of NSAIDs is attributable to the inhibition of prostaglandin synthesis that occurs in response to blocking cyclooxygenase activity. The effective dose of NSAIDs can vary depending on pain intensity and administration timing; however, there are few studies on this. This study aimed to elucidate whether the analgesic effect of NSAIDs changes depending on the situation in which they are taken and we focused on the NSAID, aspirin (ASP). In a rat model of brewer's yeast-induced inflammation, pain caused by 20% (w/v) brewer's yeast-treatment was defined as “strong pain” and that caused by 2.5% (w/v) was defined as “weak pain”. The analgesic effect of ASP (low-dose; 44 mg/kg or high-dose; 66 mg/kg) against strong pain was dose-dependent, but that against weak pain was the same. Furthermore, we defined drug administration after 3 h of brewer's yeast-treatment as “late administration” and that after 20 min as “early administration”. In the case of strong pain, the analgesic effect of “late ASP administration” was dose-dependent, but that of “early ASP administration” was the same. These results suggest that low-dose NSAIDs have an analgesic effect against weak pain or when taken early.
In this study, we conducted a web-based survey of 800 elderly people to clarify sex and regional differences in the usefulness of individual health consultations in community pharmacies for improving the health of elderly people. The results demonstrated that the health consultations were more useful for those with high health consciousness than those with low health consciousness and men living alone had the greatest need for health consultations. Among residents of urban areas, “physical activity and exercise” affected the usefulness of the health consultations for both men and women. In contrast, among residents of rural areas, “nutrition and dietary habits” affected the usefulness of the health consultations for both men and women. These results demonstrate that individual health consultations with elderly people focus on problems other than the side effects of medications. Therefore, it is expected that such consultations will continue to contribute substantially to the health of residents in the future. It is necessary for pharmacies to provide consultations on a more diverse range of issues and to be recognized by residents as providers of medical advice in the community.
The purpose of this study was to examine how students prepare for the pharmaceutical technical English course “Yakugaku-Eigo Nyumon” by qualitative analysis. A sub-text, supplemental material was used to assist students with class preparation. Qualitative questionnaires on understanding and approaches for class preparation as well as review of class were analyzed in comparison with different academic performance levels on the final exam. The results of qualitative analysis of class preparation based on coding revealed that high-academic-performing students understood and adopted deep-processing approaches for the preparation of “English words” and “understanding of content” more often than low-academic-performing students. High-performing students attempted to not literally translate English sentences into Japanese while checking the English words with thinking and ingenuity, and to understand English sentences by drawing figures and thinking of relationships using previously learned knowledge. These approaches were not adopted by low-performing students. Furthermore, sub-text was one of the means for understanding by high-performing students, whereas it was essential for low-performing students to understand the content. Coding results on the review of class also showed that low-performing students were dependent mainly on sub-text for understanding. These results suggest that deep-processing approaches to both English and content of materials are necessary for deep understanding in “Yakugaku-Eigo Nyumon”.
Phellodendron amurense is a broad-leaved tree; its outer bark and cork layers are removed and used as a crude medicinal agent known as Phellodendri Cortex. These trees are cultivated for approximately 15 to 20 years, harvested by felling, and processed by separating the outer and inner bark. Conventionally, parts other than the inner bark (i.e., fruit, leaves, and heartwood) remain unused. However, the revenue earned from by-products could contribute to continued cultivation of Phellodendron amurense. Herein, we examined the extraction condition and investigated the content of chlorogenic acid in the leaves of domestic Phellodendron amurense, which possesses antioxidant activity.