Unkeito promotes follicle development by restoring reduced follicle-stimulating hormone responsiveness in rats with polycystic ovary syndrome.

Background: Polycystic ovary syndrome (PCOS) is a common disorder resulting in irregular menstruation and infertility due to improper follicular development and ovulation. PCOS pathogenesis is mediated by downregulated follicle-stimulating hormone receptor (FSHR) expression in granulosa cells (GCs); however, the underlying mechanism remains elusive. Unkeito (UKT) is a traditional Japanese medicine used to treat irregular menstruation in patients with PCOS. In this study, we aimed to confirm the effectiveness of UKT in PCOS by focusing on follicle-stimulating hormone (FSH) responsiveness. Methods: A rat model of PCOS was generated by prenatal treatment with 5α-dihydrotestosterone. Female offspring (3-week-old) rats were fed a UKT mixed diet or a normal diet daily. To compare the PCOS phenotype in rats, the estrous cycle, hormone profiles, and ovarian morphology were evaluated. To further examine the role of FSH, molecular, genetic, and immunohistological analyses were performed using ovarian tissues and primary cultured GCs from normal and PCOS model rats. Results: UKT increased the number of antral and preovulatory follicles and restored the irregular estrous cycle in PCOS rats. The gene expression levels of FSHR and bone morphogenetic protein (BMP)-2 and BMP-6 were significantly decreased in the ovarian GCs of PCOS rats compared to those in normal rats. UKT treatment increased FSHR staining in the small antral follicles and upregulated Fshr and Bmps expression in the ovary and GCs of PCOS rats. There was no change in serum gonadotropin levels. In primary cultured GCs stimulated by FSH, UKT enhanced estradiol production, accompanied by increased intracellular cyclic adenosine monophosphate levels, and upregulated the expression of genes encoding the enzymes involved in local estradiol synthesis, namely Cyp19a1 and Hsd17b. Furthermore, UKT elevated the expression of Star and Cyp11a1, involved in progesterone production in cultured GCs in the presence of FSH. Conclusions: UKT stimulates ovarian follicle development by potentiating FSH responsiveness by upregulating BMP-2 and BMP-6 expression, resulting in the recovery of estrous cycle abnormalities in PCOS rats. Restoring the FSHR dysfunction in the small antral follicles may alleviate the PCOS phenotype.

Role of p53 in Cisplatin-Induced Myotube Atrophy.

Chemotherapy-induced sarcopenia is an unfavorable prognostic factor implicated in the development of postoperative complications and reduces the quality of life of patients with cancer. Skeletal muscle loss due to cisplatin use is caused by mitochondrial dysfunction and activation of muscle-specific ubiquitin ligases Atrogin-1 and muscle RING finger 1 (MuRF1). Although animal studies suggest the involvement of p53 in age-, immobility-, and denervation-related muscle atrophy, the association between cisplatin-induced atrophy and p53 remains unknown. Herein, we investigated the effect of a p53-specific inhibitor, pifithrin-alpha (PFT-α), on cisplatin-induced atrophy in C2C12 myotubes. Cisplatin increased the protein levels of p53, phosphorylated p53, and upregulated the mRNA expression of p53 target genes PUMA and p21 in C2C12 myotubes. PFT-α ameliorated the increase in intracellular reactive oxygen species production and mitochondrial dysfunction, and also reduced the cisplatin-induced increase in the Bax/Bcl-2 ratio. Although PFT-α also reduced the cisplatin-induced increase in MuRF1 and Atrogin-1 gene expression, it did not ameliorate the decrease in myosin heavy chain mRNA and protein levels and muscle-specific actin and myoglobin protein levels. We conclude that cisplatin increases muscle degradation in C2C12 myotubes in a p53-dependent manner, but p53 has minimal involvement in the reduction of muscle protein synthesis.

Role of Mitochondrial Dysfunction in the Pathogenesis of Cisplatin-Induced Myotube Atrophy.

Muscle atrophy is commonly observed during cisplatin chemotherapy, leading to a reduced QOL in cancer patients. Reduced skeletal muscle mass caused by cisplatin treatment results from the activation of ubiquitin ligases-Atrogin-1 and MuRF1, but the precise mechanisms are poorly understood. In this study, we investigated the possible involvement of mitochondrial dysfunction, including reactive oxygen species (ROS) generation and ATP production, in cisplatin-induced muscle atrophy. Skeletal C2C12 myotubes were treated with cisplatin, and gene and protein expression were evaluated. Mitochondrial mass, membrane potential, and ROS levels were measured using fluorescent dyes. Mitochondrial respiratory function, ATP production rates, and glycolytic capacity were also analyzed using an extracellular flux analyzer. Metabolomic analyses were performed using gas chromatography-tandem mass spectrometry. Cisplatin treatment reduced myosin heavy chain expression by activating the ubiquitin-proteasome system. Increased ROS production was observed after cisplatin treatment, followed by significant changes in apoptosis-related gene expression and decrease in mitochondrial mass, membrane potential, respiration, and ATP production. Glycolytic capacity and tricarboxylic acid (TCA) cycle metabolite levels were reduced with cisplatin treatment. Mitochondria-targeted antioxidant mitoquinone mesylate prevented up-regulation of Atrogin-1 gene expression and restored myosin heavy chain levels, accompanied by a decrease in ROS generation, but not mitochondrial ATP production. We concluded that cisplatin-induced myotube atrophy was associated with mitochondrial dysfunction. Reducing ROS generation, rather than promoting ATP production, could be a useful therapeutic strategy for preventing cisplatin-induced muscle atrophy.

Tokishakuyakusan ameliorates lowered body temperature after immersion in cold water through the early recovery of blood flow in rats.

ETHNOPHARMACOLOGICAL RELEVANCE: 'Cold feeling' is a subjective feeling of unusual coldness that aggravates fatigue, stiffness, and other symptoms, thereby reducing quality of life. Tokishakuyakusan (TSS) is a Kampo medicine reported to improve cold feeling and is used to treat symptoms aggravated by cold feeling. However, the mechanism of action of TSS is unclear. Cold feeling may involve reduced blood flow and subsequent inhibition of heat transport. Therefore, elucidating the effects of TSS on blood flow is one of the most important research topics for clarifying the mechanism of action of TSS. AIM OF THE STUDY: We aimed to evaluate the effect of TSS on recovery from lowered body temperature by the immersion of rats in cold water and to clarify the involvement of blood flow in the action of TSS. MATERIALS AND METHODS: After female Wistar rats underwent 9 days of low room temperature stress loading (i.e. room temperature of 18 °C), they were subjected to immersion in cold water (15 °C) for 15 min. Body surface temperature, rectal temperature, and plantar temperature were measured before and after immersion in cold water. Blood flow was measured before and after immersion in cold water without low room temperature stress loading. TSS (0.5 g/kg or 1 g/kg) or the vehicle (i.e. distilled water) was orally administered once daily for 10 days for the measurement of body temperature or once 30 min before immersion in cold water for the measurement of blood flow. In addition, we examined the effect of TSS on calcitonin gene-related peptide (CGRP) release from dorsal root ganglion (DRG) cells, the effect of TSS ingredients on transient receptor potential (TRP) channels, and the effect of TSS ingredients on the membrane potential of vascular smooth muscle cells and evaluated the mechanism of the effects of TSS on blood flow. RESULTS: Body temperature and blood flow decreased after immersion in cold water and then recovered over time. A comparison of body temperature at each timepoint or area under the curve showed that TSS (1 g/kg) accelerated the recovery of body surface temperature, rectal temperature, and blood flow. TSS significantly increased CGRP release from DRG cells, which disappeared after pretreatment with HC-030031 (a transient receptor potential ankyrin 1 [TRPA1] antagonist). The effects of seven TSS ingredients on TRP channels were examined. The agonistic effect on TRPA1 was observed for atractylodin, atractylodin carboxylic acid and levistolide A. Among the TSS ingredients, atractylodin carboxylic acid had significant hyperpolarising effects. CONCLUSIONS: The mechanism by which TSS accelerates the recovery of lowered body temperature in rats after immersion in cold water may involve the acceleration of the recovery of lowered blood flow. Increased CGRP release from DRG cells by TSS, TRPA1 activation by TSS ingredients, and membrane potential changes in vascular smooth muscle cells caused by TSS ingredients are part of the mechanism of action of TSS. These findings may partly contribute to the interpretation of the beneficial effects of TSS on cold feeling.

The ameliorating effects of tokishakuyakusan in a rat model of implantation failure involves endometrial gland leukemia inhibitory factor and decidualization.

ETHNOPHARMACOLOGICAL RELEVANCE: Tokishakuyakusan (TSS) is a Kampo medicine that is prescribed for the treatment of infertility in Japan. However, its precise mechanism of action remains unclear. AIM OF THE STUDY: Leukemia inhibitory factor (LIF) in the endometrium plays an indispensable role in embryo implantation and is linked to infertility or implantation failure. Previously, we demonstrated that TSS ameliorated implantation failure induced by mifepristone (RU-486), an antagonist of progesterone, in rats. Herein, we aimed to clarify whether the ameliorating effect of TSS on implantation failure in the rat model involves endometrial LIF. Additionally, we determined whether decidualization, the dysfunction of which is linked to infertility or implantation failure similar to LIF, progesterone, and other implantation-related factors, are involved in the effect of TSS. MATERIALS AND METHODS: The implantation failure rat model was developed via the subcutaneous administration of RU-486 (7 mg/kg) on day 3 post-coitus. Sesame oil was administered as the vehicle control. Rats were fed a diet containing 1% or 3% TSS or a control diet from day 13 pre-coitus. Subsequently, the implantation sites were assessed, and plasma progesterone levels were analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) on day 8 post-coitus. The LIF mRNA of the endometrial gland, which was segmented via laser-microdissection from the endometrial tissue, was measured, and endometrial LIF immunostaining was carried out on day 5. The gene expression of different factors related to implantation, including decidualization and progesterone-responsiveness on days 5 and 6, were measured. The human endometrial Ishikawa cell line derived from human adenocarcinoma was treated with TSS (30-300 µg/mL) for 24 h, and the LIF concentrations in the cell culture supernatants were measured. RESULTS: RU-486 decreased the number of implantation sites in the uterus of rats; however, the decrease was significantly alleviated by TSS (3%-diet), which tended to increase plasma progesterone. In rats with RU-486-induced implantation failure, endometrial gland LIF mRNA and endometrial LIF protein were markedly decreased while the gene expression of both decidualization-related factors such as interleukin-11, insulin-like growth factor binding protein-1, and cyclooxygenase-2, and progesterone responsive-related factors such as FK506 binding protein 5, were significantly decreased. These changes in the uterus of rats with implantation failure were significantly alleviated by TSS (3%-diet). Additionally, TSS significantly enhanced LIF protein production and LIF mRNA in Ishikawa cells. CONCLUSIONS: The mechanism whereby TSS ameliorates RU-486-induced implantation failure in rats may involve the alleviation of decreased LIF production derived from the endometrial gland, and a dysfunction of decidualization, including lower progesterone responsiveness in the model. These findings may partly contribute to the interpretation of the beneficial effects of TSS on infertility.

Psychological stress in aged female mice causes acute hypophagia independent of central serotonin 2C receptor activation.

Sex differences exist in the activation of the hypothalamic-pituitary-adrenal axis following exposure to stress, and the stress response is further affected by aging. This study was conducted to elucidate the mechanism of hypophagia in aged female mice exposed to stress. Immediately after a stress load, aged female mice exhibited acute hypophagia and a rise in plasma corticosterone levels. The administration of a serotonin 2C receptor (5-HT2CR) antagonist suppressed plasma corticosterone but did not affect the reduction in food intake. In contrast, an endogenous ghrelin enhancer, rikkunshito (RKT), significantly inhibited the reduction in food intake. An increase in peripheral acylated ghrelin levels during fasting, which occurs in young mice, was not observed in aged female mice. Moreover, in these mice, significantly increased levels of ghrelin and gastric preproghrelin mRNA expression were observed in the fed status. Moreover, plasma ghrelin levels were elevated by RKT and not by the 5-HT2CR antagonist. In female mice, the hypothalamic non-edited (INI) and partially edited mRNA 5-HT2CR isoforms (VNV, VNI, VSV or VSI) decreased with age, while in male mice, the editing isoform was unchanged by aging or stress. Estrogen receptor α (ERα)-positive cell counts in the arcuate nucleus of young male mice exposed to stress and control aged male mice were increased compared with those in young control mice. In aged male mice exposed to stress, the number of ERα-expressing cells in the paraventricular nucleus were significantly increased compared with those in aged control mice; in female mice, there was no increase in the number of ERα-positive cells. Hypophagia in aged female mice exposed to stress may be independent of 5-HT2CR activation. It seems likely that the mechanisms may be caused by sex dependent, differential regulation in 5-HT2CR mRNA expression, peripheral acylated ghrelin secretion and/or hypothalamic ERα expression.

[6]-gingerol and [6]-shogaol, active ingredients of the traditional Japanese medicine hangeshashinto, relief oral ulcerative mucositis-induced pain via action on Na+ channels.

The traditional Japanese herbal medicine hangeshashinto (HST) has beneficial effects for the treatment of oral ulcerative mucositis (OUM) in cancer patients. However, the ingredient-based mechanism that underlies its pain-relieving activity remains unknown. In the present study, to clarify the analgesic mechanism of HST on OUM-induced pain, we investigated putative HST ingredients showing antagonistic effects on Na+ channels in vitro and in vivo. A screen of 21 major ingredients using automated patch-clamp recordings in channel-expressing cells showed that [6]-gingerol and [6]-shogaol, two components of a Processed Ginger extract, considerably inhibited voltage-activated Na+ currents. These two ingredients inhibited the stimulant-induced release of substance P and action potential generation in cultured rat sensory neurons. A submucosal injection of a mixture of [6]-gingerol and [6]-shogaol increased the mechanical withdrawal threshold in healthy rats. In a rat OUM model, OUM-induced mechanical pain was alleviated 30min after the swab application of HST despite the absence of anti-bacterial and anti-inflammatory actions in the OUM area. A swab application of a mixture of [6]-gingerol and [6]-shogaol induced sufficient analgesia of OUM-induced mechanical or spontaneous pain when co-applied with a Ginseng extract containing abundant saponin. The Ginseng extract demonstrated an acceleration of substance permeability into the oral ulcer tissue without an analgesic effect. These findings suggest that Na+ channel blockage by gingerol/shogaol plays an essential role in HST-associated analgesia of OUM-induced pain. This pharmacological mechanism provides scientific evidence supporting the use of this herbal medicine in patients suffering from OUM-induced pain.

Effects of Hangeshashinto on Growth of Oral Microorganisms.

Oral mucositis (OM) in cancer patients induced by chemotherapy or radiotherapy has a significant impact on quality of life, and causes considerable morbidity. Oral microorganisms are likely to intensify the inflammatory process and aggravate the formation of ulcers. Hangeshashinto (HST), a Japanese kampo medicine, has been reported to be effective when used as a gargle for the treatment of OM. To clarify the effects of HST on oral microorganisms, we assessed its antimicrobial activity against 27 microbial species, including 19 oral bacteria and one fungus. HST extract inhibited the growth of Gram-negative bacteria, including Fusobacterium nucleatum, Porphyromonas gingivalis, Porphyromonas endodontalis, Prevotella intermedia, Prevotella melaninogenica, Tannerella forsythia, Treponema denticola, and Porphyromonas asaccharolytica, though inhibitory effects were less pronounced for Gram-positive bacteria and the fungal strain. We then investigated the effects of antibacterial activities on 15 purified ingredients of HST and determined that baicalein, berberine, coptisine, [6]-shogaol, and homogentisic acid actively inhibited the growth of these bacteria. These findings showed that HST inhibits the growth of specific Gram-negative periodontopathogenic bacteria, which are significant pathogens in OM, without disturbing the normal oral flora. Our data suggest that HST may be a useful treatment for OM in patients undergoing anticancer treatment.

Analysis of the antioxidative function of the radioprotective Japanese traditional (Kampo) medicine, hangeshashinto, in an aqueous phase.

Oral mucositis (OM) is a common and painful complication of radiotherapy for head and neck cancer. Hangeshashinto (HST), a Japanese traditional medicine, is known to alleviate radiotherapy- and/or chemotherapy-induced OM; however, the detailed mechanism has not yet been clarified. The aim of the present study was to clarify the details of the antioxidative functions of HST against reactive oxygen species (ROS) produced by radiation. The hydroxyl radical (•OH)-scavenging ability and the reduction ability was simultaneously measured using a modified electron paramagnetic resonance (EPR) spin-trapping method. The superoxide (O(2) (•-))-scavenging ability was estimated by an EPR redox probing method. Water suspensions of powdered HST and of its seven constitutive crude drugs were tested. In addition, some of the main water-soluble ingredients of the crude drugs were also tested. HST was found to scavenge both •OH and O(2) (•-). Furthermore, HST was observed to reduce relatively stable nitroxyl radicals. Glycyrrhizae Radix (kanzo), Ginseng Radix (ninjin), Zizyphi Fructus (taiso) and glycyrrhizin (an ingredient of kanzo) were all found to be relatively good •OH scavengers. Scutellariae Radix (ogon) and Coptidis Rhizoma (oren) demonstrated reducing ability. In addition, acteoside and berberine chloride, which are water-soluble ingredients of ogon and oren, respectively, also demonstrated reducing ability. Oren exhibited oxidative ability at higher concentrations, which may have a function in maintaining catalytic redox action. The antioxidative function of HST probably worked via a balance of scavenging ROS, reducing stable free radicals, and some minor oxidizing activities.

Multitargeted effects of hangeshashinto for treatment of chemotherapy-induced oral mucositis on inducible prostaglandin E2 production in human oral keratinocytes.

OBJECTIVE: Chemotherapy-induced oral mucositis (COM) is characterized by painful inflammation with prolonged damage that involves the pathological pain-evoking prostaglandin E2 (PGE2). We previously found that gargling with hangeshashinto (HST), a traditional Japanese medicine, was effective for the treatment of COM. However, little is known regarding the mechanisms. Our aim was to identify the active ingredients and clarify the characteristic effects of HST on the PGE2 system. METHODS: Prostanoids produced by human oral keratinocytes (HOK) stimulated with IL-1ß were measured by enzyme immunoassay. Active ingredients that regulate PGE2 production were identified and quantified by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and a culture system of HOK cells. RESULTS: Inducible PGE2, PGD2, and PGF2α, metabolites of cyclooxygenase (COX) pathways, were reduced by HST (10-300 µg/mL) without inducing cytotoxicity. The active ingredients of HST were quantified by LC-MS/MS, and [6]-shogaol, [6]-gingerol, wogonin, baicalein, baicalin, and berberine were shown to reduce PGE2 production. A mixture of these 6 ingredients at concentrations equal to 300 µg/mL of HST strongly suppressed PGE2 production to the same level as HST. [6]-Shogaol and [6]-gingerol did not decrease COX-2 mRNA expression and mostly inhibited PGE2 metabolic activity in an assay using intact HOK cells, suggesting that they regulate PGE2 synthesis at the posttranscriptional level. Wogonin, baicalin, and berberine inhibited expression of COX-2 mRNA without affecting PGE2 metabolic activity. Moreover, wogonin, but not [6]-shogaol, suppressed phosphorylation of mitogen-activated protein kinases (p38s and JNKs). CONCLUSIONS: These lines show that HST includes several PGE2-regulating ingredients that have different mechanisms and can function as a multicomponent and multitarget agent for treatment of COM, indicating that HST may be beneficial in a new medical strategy for COM treatment.

Protective effect of the Japanese traditional medicine juzentaihoto on myelosuppression induced by the anticancer drug TS-1 and identification of a potential biomarker of this effect.

BACKGROUND: TS-1 is an oral anticancer drug containing a 5-fluorouracil derivative (Tegafur) that is widely used in Japan for the treatment of cancer, especially gastrointestinal tumors. Frequently, however, TS-1 therapy has to be discontinued because of leukopenia. If it were possible to predict the development of bone marrow suppression before the white blood cell (WBC) count had actually decreased, treatment could be improved by strict dosage control and/or the prophylactic administration of hematopoietic drugs. Juzentaihoto (JTT), a traditional Japanese medicine (Kampo), has been reported to activate hematopoiesis and reduce the side effects associated with chemotherapy and radiotherapy. Here, we 1) evaluate the efficacy of JTT in alleviating myelosuppression induced by TS-1 therapy in mice, and 2) explore biomarkers that reflect both induction by TS-1 and alleviation by JTT of bone marrow suppression using a proteomics approach. METHODS: Ten mg/kg of TS-1 was administered to Balb/c mice with or without 1 g/kg of oral JTT for 3, 5 and 7 days. WBC count and ratio of CD34+ bone marrow cells (BMCs) were estimated by flow cytometry. Plasma samples were analyzed using surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI TOF-MS). A biomarker candidate from SELDI profiling was identified using a combination of cation exchange spin column purification, SDS-PAGE, enzymatic digestion and LC-MS/MS. RESULTS: After administration of TS-1, a significant decrease in WBC count and CD34+ BMC ratio were observed at days 5 and 3, respectively. JTT treatment improved WBC count on day 7 and CD34+ BMC ratio on days 5 and 7. SELDI analysis highlighted three protein peaks that had increased on day 3 after treatment with TS-1 but remained unchanged in mice co-treated with JTT. One of the three peaks, m/z 4223.1, was further investigated and identified as a specific C-terminal fragment of albumin. CONCLUSION: This study indicates that bone marrow suppression by treatment with TS-1 in mice might be improved by coadministration of JTT. A C-terminal fragment of albumin was identified as a candidate biomarker for predicting TS-1-induced myelosuppression. However, the sensitivity and specificity of the biomarker candidate must be validated in future clinical studies.

A Proteomic Approach for the Diagnosis of 'Oketsu' (blood stasis), a Pathophysiologic Concept of Japanese Traditional (Kampo) Medicine.

'Oketsu' is a pathophysiologic concept in Japanese traditional (Kampo) medicine, primarily denoting blood stasis/stagnant syndrome. Here we have explored plasma protein biomarkers and/or diagnostic algorithms for 'Oketsu'. Sixteen rheumatoid arthritis (RA) patients were treated with keishibukuryogan (KBG), a representative Kampo medicine for improving 'Oketsu'. Plasma samples were diagnosed as either having an 'Oketsu' (n = 19) or 'non-Oketsu' (n = 29) state according to Terasawa's 'Oketsu' scoring system. Protein profiles were obtained by surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF MS) and hierarchical clustering and decision tree analyses were performed. KBG treatment for 4 or 12 weeks decreased the 'Oketsu' scores significantly. SELDI protein profiles gave 266 protein peaks, whose expression was significantly different between the 'Oketsu' and 'non-Oketsu' states. Hierarchical clustering gave three major clusters (I, II, III). The majority (68.4%) of 'Oketsu' samples were clustered into one cluster as the principal component of cluster I. The remaining 'Oketsu' profiles constituted a minor component of cluster II and were all derived from patients cured of the 'Oketsu' state at 12 weeks. Construction of the decision tree addressed the possibility of developing a diagnostic algorithm for 'Oketsu'. A reduction in measurement/pre-processing conditions (from 55 to 16) gave a similar outcome in the clustering and decision tree analyses. The present study suggests that the pathophysiologic concept of Kampo medicine 'Oketsu' has a physical basis in terms of the profile of blood proteins. It may be possible to establish a set of objective criteria for diagnosing 'Oketsu' using a combination of proteomic and bioinformatics-based classification methods.

Identification of a predictive biomarker for the beneficial effect of a Kampo (Japanese traditional) medicine keishibukuryogan in rheumatoid arthritis patients.

OBJECTIVES: Kampo (Japanese traditional herbal) medicines are now ethically used in Japan as pharmaceutical grade prescription drugs. However, there are distinct groups of responders and non-responders to Kampo medicines. We searched for biomarker candidates to discriminate responders from non-responders to keishibukuryogan (KBG); one of the most frequently used Kampo medicines. DESIGN AND METHODS: A combination of SELDI technology and a decision tree analysis with proprietary developed bioinformatics tools was applied to 41 (32 for tree construction and 9 for validation test) plasma samples obtained from rheumatoid arthritis (RA) patients. A candidate biomarker protein was identified using LC-MS/MS. RESULTS: The constructed tree with measurable reliability contained only a single peak which was identified as haptoglobin alpha 1 chain (Hpalpha1). CONCLUSION: Hpalpha1 is a biomarker candidate for discriminating responders from non-responders to KBG treatment for RA. The present results may open the way to the establishment of "evidence-based" complementary and alternative medicine.

Administration of substance P during a primary immune response amplifies the secondary immune response via a long-lasting effect on CD8+ T lymphocytes.

Atopic dermatitis can be exacerbated or induced by scratching or psychological stress; both cause the release of substance P (SP) from sensory nerves. Therefore, SP may have an etiological role in mechanisms underlying AD. Here, we show that administration of SP during the primary immune response (PIR) imprinted long-lasting pro-inflammatory immunity, resulting in exacerbation of the secondary immune response (SIR) in the absence of further SP. Five days after sensitization with dinitrofluorobenzene (DNFB), challenge with DNFB together with SP ("SP-Group") resulted in an increased PIR (as evaluated by ear swelling and granulocyte infiltration) compared to DNFB only ("Control-Group"). On day 26, after inflammation completely subsided, a second challenge with DNFB only (without SP) caused an increased SIR in the "SP-Group" compared to controls. Pretreatment on day 5 with spantide, an SP receptor antagonist, prevented increased ear swelling in the "SP-Group" not only on day 5 (PIR) but also on day 26 (SIR). In contrast, spantide treatment on day 26 did not affect the SIR. Adoptive transfer experiments suggested that CD8(+) T cells were involved in mediating enhanced SIR in animals pretreated on day 5 with SP. The present study offers a novel experimental approach to an uninvestigated facet of the pro-inflammatory effect of SP, i.e., exacerbation of inflammation via a long-term and indirect influence on CD8(+) T lymphocytes.