Chemotherapy-induced peripheral neuropathy (CIPN) considerably impairs cancer patients’ QOL, and may lead to discontinuation of drug treatment of cancer. Currently, there is no effective strategy against CIPN. Therefore, it is an urgent issue to develop clinically available drugs that prevent or treat CIPN. We have shown that high mobility group box 1 (HMGB1), a damage-associated molecular pattern (DAMP) molecule, plays an essential role in the development of CIPN. Most interestingly, thrombomodulin α, approved as a medicine for treatment of disseminated intravascular coagulation (DIC) in Japan, causes thrombin-dependent degradation of extracellular HMGB1 that is released in response to chemotherapeutics, and prevents CIPN. Thus, we expect that targeting HMGB1 or its receptors would lead to prevention of CIPN in cancer patients in near future.

Chemotherapy-induced peripheral neuropathy (CIPN) is a side effect frequently caused by taxanes. Because the mechanisms underlying CIPN pathogenesis remain to be fully elucidated, there is no indicator for objective diagnosis like a biomarker. In addition, treatment options for CIPN is still unsatisfactory. We have previously demonstrated that paclitaxel preferentially impair myelin-forming Schwann cells, and consequently induce dedifferentiation and demyelination of Schwann cells. Recently, in a paclitaxel CIPN model mouse, we found that an inflammatory factor is released from dedifferentiated Schwann cells in the mouse sciatic nerve into the blood, highly correlated with the on-set of mechanical hypersensitivity. On the other hand, considering our previous findings, it seems that some drugs, which supply newly formed mature Schwann cells at the sites of demyelinated lesions, may be a new beneficial therapy for taxane-induced peripheral neuropathy. In this review, we will introduce our findings about new therapeutic drug candidate for taxane-related CIPN based on this concept, and plasma biomarker to detect CIPN on-set and progression.

Chemotherapy induced peripheral neuropathy (CIPN) is a numbness or tingling of the hands and feet that occur as a side effect of anticancer drugs including taxanes and platinum drugs. The effective treatments or preventive strategy are not established. Once it develops, symptoms persist for a long time and cause impairment in activity of daily living. Topical cooling is a preventive strategy for side effects of chemotherapy such as hair loss, oral microsites, and skin and nail disorder of the hands and feet. We conducted a clinical trial in breast cancer patients who received paclitaxel treatment to assess the effectiveness of cooling for CIPN prevention. In this study, the individual background factor was standardized using an intra-individual comparison design. In 40 subjects, frozen gloves and socks were applied on the dominant hand and foot from 15 minutes before the anti-cancer drug administration to 15 minutes after the end of administration (total 90 minutes) and compared with non-dominant hand and foot. As a result, clinically and statistically significant differences were observed for changes in tactile threshold evaluated by the monofilament test, subjective symptoms, and changes in dexterity evaluated by functional test. The current cooling system has not been well implemented in oncology field due to the lack of facility and human resources. To deliver this therapy broadly, it will be urgent to develop a medical cooling device that can provide safe and effective cryotherapy.

Benign prostatic hyperplasia/benign prostatic enlargement (BPH/BPE) is a common proliferative disease, and giving rise to associate with lower urinary tract symptoms (LUTS). However, the pathogenesis is not well clarified, and thought to be multifactorial. There are some lines of evidence that impairment in the blood supply of the lower urinary tract causes development of BPH/BPE. Clinical data showed an association between the development of BPH/BPE and atherosclerotic disease such as hypertension, diabetes and hyperlipidemia. The spontaneously hypertensive rat (SHR) has been used as model of genetic hypertension. SHR also shows decreased blood flow and hyperplastic morphological abnormalities in the ventral prostate. Our previous studies demonstrated that chronic treatment with vasodilative drugs nicorandil (ATP sensitive potassium channel opener) and silodosin (alpha1 adrenoceptor antagonist) increased blood flow and suppressed the growth factor and morphological abnormalities in the SHR ventral prostate. These data suggested that prostatic blood flow could be therapeutic targets for BPH/LUTS.

Bladder afferent nerves are composed by myelinated Aδ- and unmyelinated C-fibers. During the storage phase of urine, distention of the bladder has long been considered to evoke afferent activity via Aδ-fibers connected in series with the smooth muscle fibers. In contrast, a previous study in cats revealed that more than 90% of C-fibers do not respond to normal bladder distension, being so called 〝silent〟 fibers. However, at least in rats, C-fibers can respond to normal bladder distension like Aδ-fibers, although they may also fulfill a potentially different role in the bladder sensory function in response to abnormal stimuli. The symptoms of overactive bladder (OAB) or interstitial cystitis (IC) are believed to be commonly related to the sensory (afferent) function. In addition, it has been suggested that bladder myogenic microcontractions or micromotions may partly contribute to the development of urgency in OAB related to bladder outlet obstruction (BOO), which is one of cause of benign prostatic hyperplasia (BPH). We have investigated the direct effects of drugs (anticholinergics, β3-adrenoceptor agonists, α1-adrenoceptor antagonists, PDE type5 inhibitors, etc.) on the bladder afferent function in rodents. In our results, almost all drugs may act on the bladder afferent function, and some of drug (e.g. mirabegron) inhibits the afferent activities through the suppression of the bladder myogenic microcontractions in normal or pathophysiological conditions.

Chronic prostatitis / chronic pelvic pain syndrome (CP/CPPS) is commonly diagnosed in men younger than 50 years old. It is characterized by pelvic pain, voiding symptoms and sexual dysfunction. The considerable discomfort or pain experienced has a negative impact on the quality of life of patients and is a huge economic burden because of the high recurrence rate and the low cure rate. Appropriate animal models are essential for the development of new drugs for the treatment of CP/CPPS, and several rodent models induced by different methods and over different time frames have been established. This article reviews studies of three in vivo rodent models of prostatitis, namely, chemical-induced, autoimmune-induced and hormone-associated models reported by us and other investigators. Recent clinical investigation has suggested that tadalafil improves the International Prostatic Symptom Score and the total National Institutes of Health Chronic Prostatitis Symptom Index score of patients with benign prostatic hyperplasia with CP/CPPS, which enables us to investigate the effect of tadalafil on the pelvic-pain-related behavior and prostatic inflammation in two of these prostatitis model types, experimental autoimmune prostatitis (EAP) and hormone/castration-induced prostatitis (HCP). Both models showed the pelvic-pain-related behavior and prostatic inflammation that are characteristic of chronic prostatitis. In EAP, tadalafil suppressed both the pelvic-pain-related behavior and the prostatic inflammation. In HCP, tadalafil suppressed the pelvic-pain-related behavior. These results mimic the clinical findings. Therefore EAP and HCP are suitable for the evaluation of the potency of drugs for the treatment of CP/CPPS.

As Japan enters into an aging society, aged patients with chief complaint of lower urinary tract symptoms (LUTS) have increased. The most common cause of LUTS in men older than 50 years is benign prostatic hyperplasia (BPH). In particular, LUTS associated with overactive bladder (OAB) symptoms was reported to have a significant negative impact on patient quality of life (QOL). In clinical practice, monotherapy with α1-blockers or PDE5 inhibitors is widely employed for the initial management of BPH accompanied by OAB (BPH/OAB). However, storage symptoms may persist in some patients. In patients with residual OAB symptoms despite α1-blocker or PDE5 inhibitor monotherapy, the addition of an anticholinergic agent or a β3-adrenergic receptor (β3-AR) agonist is recommended by the BPH guidelines. Although both agents have been shown to effectively improve OAB symptoms and bladder storage functions, it remains unclear which type of add-on therapy, anticholinergic agents or β3-AR agonists, is most effective for alleviating OAB symptoms and storage functions. Recently, detrusor underactivity (DU) is also considered to be a common cause of non-neurogenic LUTS in men. DU has been reported to be present in 9%–48% of men undergoing urodynamic evaluation for non-neurogenic LUTS. DU can lead to adverse health effects, in addition to significant burden and decreased QOL. Thus, development of a safe and effective treatment for patients with LUTS induced by DU is an urgent issue at present. In this paper, we will introduce most recent findings of curative drugs for LUTS, especially BPH/OAB and DU in clinical practice.

In the 18^th century, Edward Jenner proposed the vaccine for smallpox as a first vaccine therapy based on the legend that a vaccinia prevents the infection with smallpox. Recently, the therapeutic target of vaccine will expand from infectious diseases to various diseases, such as amyloid β or tau vaccine for Alzheimer’s disease. We are now going to develop a therapeutic vaccine to lifestyle-related diseases (i.e. high blood pressure), and aim to realize a novel therapy which will be injected once or twice per year from a daily medication. For this purpose, the appropriate choice of an antigen, carrier and adjuvants should be required to activate hormonal immunity by the vaccine, leading to efficient antibody production without toxicity, because the therapeutic target of our vaccine is an endogenous protein (i.e. hormone). The clinical advantage of this therapeutic vaccine is to improve the medical adherence and drug management because the multiple drug users are increased in particular old patients, so called polypharmacy. If the vaccine will take place of a part of medicine in future, it may give us a novel therapeutic option with several social benefits.

Brexpiprazole (Rexulti^®) is the second antipsychotic agent in the world with dopamine D2 receptor partial agonist which was developed by Otsuka Pharmaceutical Co. Ltd. It is categorized as 〝Serotonin- dopamine Activity Modulator (SDAM)〟 that regulates both serotoninergic and dopaminergic systems by acting as a partial agonist for serotonin 5-HT1A receptors and D2 receptors and as an antagonist for 5-HT2A receptors. In preclinical pharmacological studies, brexpiprazole showed the equivalent antipsychotic-like effects to those of other atypical antipsychotics. And it was suggested that brexpiprazole has the low potentials to induce extrapyramidal symptoms, hyperprolactinemia and tardive dyskinesia, with improvement effects on cognitive dysfunction. Furthermore, brexpiprazole has the weak effects on histamine H1 receptors which are associated with sedation and weight gain in clinical. In the clinical trials in patients with schizophrenia in both acute and maintenance phase, brexpiprazole showed improvement of antipsychotic effects against placebo, and low incidence of adverse events, e.g., extrapyramidal symptoms, hyperprolactinemia, and weight gain, as suggested in preclinical studies. Furthermore, brexpiprazole showed low incidence of metabolic abnormalities. In particular, brexpiprazole showed relatively low incidences of akathisia, insomnia and agitation which has been commonly reported with aripiprazole. This would be based on the pharmacological features of brexpiprazole that is more potent antagonism at 5-HT2A receptors and D2 receptors partial agonism with lower intrinsic activity compared to those of aripiprazole. In conclusion, brexpiprazole could be one of the antipsychotics with the most rational mechanism of action, and the better efficacy and safety/tolerability profiles would contribute to the treatment of patients with schizophrenia.