Substance P Antagonist Research Articles

Substance P aggravates ligature-induced periodontitis in mice.

Periodontitis is one of the most common oral diseases in humans, affecting over 40% of adult Americans. Pain-sensing nerves, or nociceptors, sense local environmental changes and often contain neuropeptides. Recent studies have suggested that nociceptors magnify host response and regulate bone loss in the periodontium. A subset of nociceptors projected to periodontium contains neuropeptides, such as calcitonin gene-related peptide (CGRP) or substance P (SP). However, the specific roles of neuropeptides from nociceptive neural terminals in periodontitis remain to be determined. In this study, we investigated the roles of neuropeptides on host responses and bone loss in ligature-induced periodontitis. Deletion of tachykinin precursor 1 (Tac1), a gene that encodes SP, or treatment of gingiva with SP antagonist significantly reduced bone loss in ligature-induced periodontitis, whereas deletion of calcitonin related polypeptide alpha (Calca), a gene that encodes CGRP, showed a marginal role on bone loss. Ligature-induced recruitment of leukocytes, including neutrophils, and increase in cytokines leading to bone loss in periodontium was significantly less in Tac1 knockout mice. Furthermore, intra-gingival injection of SP, but not neurokinin A, induced a vigorous inflammatory response and osteoclast activation in alveolar bone and facilitated bone loss in ligature-induced periodontitis. Altogether, our data suggest that SP plays significant roles in regulating host responses and bone resorption in ligature-induced periodontitis.

LB1017 A novel link between human hair follicle neuroimmunology and mitochondrial biology: Substance P increases intrafollicular oxidative stress and mitochondrial biogenesis

Substance P (SP) is the prototypic neuropeptide associated with emotional stress and neurogenic perifollicular inflammation and is released by sensory nerve fibers. It also promotes human hair follicle (HF) immune privilege collapse and catagen development ex vivo, and has thus been implicated in stress-related hair loss, ranging from telogen effluvium to alopecia areata. Since SP stimulates the mitochondrial release of reactive oxygen species, we have asked how SP impacts on human HF mitochondrial biology. When organ-cultured anagen scalp HFs were treated with SP (10-10 and 10-12M), this showed that the mitochondrial-encoded subunit 1 of cytochrome c oxidase (MTCO1), a key enzymatic marker of oxidative phosphorylation, and mitochondrial activity and biogenesis, was significantly upregulated. This was coupled with significantly increased expression of the mitochondrial mass and biogenesis marker, VDAC1/porin, a channel found in the mitochondrial membrane. SP also significantly increased mTORC1 activity (measured by p-S6 immunofluorescence), a known promoter of ROS production. Since we had previously shown that stress-induced HF greying is associated with VDAC1/porin upregulation, these SP effects suggest a hitherto unknown strong mitochondrial response of human scalp HFs to this stress- and sensory nerve fiber-associated neuropeptide. This invites therapeutic interventions with SP antagonists that target this novel link between mitochondrial biology and neuroimmunology of the HF under conditions of perceived stress in the future management of stress-associated human hair greying and hair loss.

The substance P/ neurokinin-1 receptor signaling pathway mediates metastasis in human colorectal SW480 cancer cells

The substance P (SP)/neurokinin-1 receptor (NK1R) system, a critical metastatic signaling pathway, can be targeted by substance P antagonists to prevent its cancer-progressive impacts. In the current study, we aimed to investigate the carcinogenic activity of the SP/NK1R system in human SW480 colorectal cancer cells and study the antagonistic impact of aprepitant (AP) by measuring MMP-2 and MMP-9 enzymatic activity. Different concentrations of SP, alone or mixed by AP, were utilized to treat SW480 cells to investigate the cells' viability and metastasis by applying Resazurin and Gelatin Zymography methods, respectively. The cells' metastatic response was analyzed by measuring the MMP-2 and MMP-9 in transcriptional and translational levels. Finally, the Scratch assay was carried out to evaluate the cells' metastatic response following the SP/AP treatment. A significant metastatic activity was observed in SW480 cells following incubation with the increasing SP doses by detecting MMP-2/MMP-9 enzyme activity, genes overexpression, and enhanced cell migration. This is while the AP treatment meaningfully diminished all the SP-mediated metastatic effects (p-Value < 0.001). According to the results, the SP/NKR1 signaling pathway can be considered one of the main metastatic effectors in human colorectal cancer. Therefore, AP might be suggested to be used as the SP antagonist and an efficient anti-metastatic drug.

The Control of Pathogenic Fungi with Trichoderma in Banjar Pinge, Tabanan of Bali Province

Pinge is one of the traditional sub-village (banjar) in Baru Village, Marga Sub district, Tabanan Regency of Bali Province. There are 36% of villagers living below the poverty line where 85% of them are farmers who cultivate fruit and flowers. They have many problems with fruit and flower production as the yields is low due to natural disasters and poor agricultural practice and support. Some flower growers often complain of low flower production, especially Marigold flowers due to the attack of pathogenic fungi that cause flower blight. The solution to solve the problems faced by partners is: by providing Appropriate Technology in the processing of cow dung into compost fertilizer plus trichoderma sp antagonist microorganisms. External targets to be achieved are the use of appropriate technology in the processing technology of cow dung into compost plus Trichoderma sp. Based on the results of activities as much as 70% understand and are able to apply pest and disease control to flowers by utilizing biological agents. Trichoderma can reduce the intensity of disease above the ground by 50.00% and suppress the intensity in the soil by 34.48%. In addition, giving Trichoderma sp. can increase the fresh weight of the plant by up to 30.75%.

Pathogenic role of the SP/ NK1R system in GBM cells through inhibiting the thioredoxin system.

Objective(s):Glioblastoma multiforme (GBM), a highly aggressive Grade IV brain tumor, is a significant public health issue due to its poor prognosis and incurability. Neuropeptide substance P (SP) plays a critical role in GBM tumor growth and development via activation of neurokinin-1receptor (NK1R). Moreover, SP is a pro-oxidant factor contributing to oxidative stress in various cell types. However, the link between SP and oxidative stress in cancer cells is not fully investigated. Here, we aimed to identify the effects of SP and NK1R antagonist, aprepitant, on the redox status of GBM cells.Materials and Methods:Resazurin assay was employed to determine the effect of aprepitant on viability of U87 glioblastoma cells. 2’,7’-dichlorodihydrofluorescein diacetate (H2DCFDA) assay was employed to measure the levels of intracellular reactive oxygen species (ROS). A quantitative real-time polymerase chain reaction was applied to measure the expression of proteins of the thioredoxin system. Commercial kits (ZellBio GmbH) were also used to measure the enzymatic activity of these proteins.Results:We found that SP increased ROS level in U87 GBM cells, and aprepitant significantly reduced this effect. Furthermore, we found that SP could also affect the thioredoxin system, a central antioxidant enzyme defense system. SP reduced both expression and enzymatic activity of the thioredoxin system’s proteins, Trx and thioredoxin reductase (TrxR) and these effects were significantly reduced by aprepitant. Conclusion:Our results indicated that SP activation of NK1R represented a link between oxidative stress and GBM and highlighted the need for further validations in future studies.

The Neurokinin-1 Receptor Antagonist Aprepitant, a New Drug for the Treatment of Hematological Malignancies: Focus on Acute Myeloid Leukemia.

Acute myeloid leukemia (AML) is a heterogeneous hematological malignancy. To treat the disease successfully, new therapeutic strategies are urgently needed. One of these strategies can be the use of neurokinin-1 receptor (NK-1R) antagonists (e.g., aprepitant), because the substance P (SP)/NK-1R system is involved in cancer progression, including AML. AML patients show an up-regulation of the NK-1R mRNA expression; human AML cell lines show immunoreactivity for both SP and the NK-1R (it is overexpressed: the truncated isoform is more expressed than the full-length form) and, via this receptor, SP and NK-1R antagonists (aprepitant, in a concentration-dependent manner) respectively exert a proliferative action or an antileukemic effect (apoptotic mechanisms are triggered by promoting oxidative stress via mitochondrial Ca++ overload). Aprepitant inhibits the formation of AML cell colonies and, in combination with chemotherapeutic drugs, is more effective in inducing cytotoxic effects and AML cell growth blockade. NK-1R antagonists also exert an antinociceptive effect in myeloid leukemia-induced bone pain. The antitumor effect of aprepitant is diminished when the NF-κB pathway is overactivated and the damage induced by aprepitant in cancer cells is higher than that exerted in non-cancer cells. Thus, the SP/NK-1R system is involved in AML, and aprepitant is a promising antitumor strategy against this hematological malignancy. In this review, the involvement of this system in solid and non-solid tumors (in particular in AML) is updated and the use of aprepitant as an anti-leukemic strategy for the treatment of AML is also mentioned (a dose of aprepitant (>20 mg/kg/day) for a period of time according to the response to treatment is suggested). Aprepitant is currently used in clinical practice as an anti-nausea medication.

Evaluation of Serum Substance P Level in Chronic Urticaria and Correlation with Disease Severity.

Substance P (SP) is a neurotransmitter emitted from neurons that plays a role in the pathogenesis of itching conditions including chronic urticarial (CU). The present research aims to investigate the serum level of S.P among CU patients and compare them with healthy subjects and explore how it correlates with the severity of urticaria. The present research was conducted on 87 CU patients who visited the allergy clinic of Ghaem Hospital, Mashhad, Iran from October 2017 to June 2018. Besides, 86 healthy subjects were recruited as the control group. Background information of patient was collected including age, sex, duration of the disease and the co-occurrence of angioedema. S.P serum level was measured in two groups by ELISA method. In the patients group, the autologous serum skin test (ASST) was performed along with the urticaria evaluation questionnaire include Urticaria Activity Score 7 (UAS7), Urticaria Control Test (UCT) and Chronic Urticaria Quality of Life (CU-Q2OL). Among the patients, the SP serum level showed to be about two times higher than the healthy subjects (p˂0.001). SP showed to be increased as patients' age grew (p=0.010). In patients with a positive ASST, SP level was higher (p=0.012). No correlation was found between SP and the presence of angioedema among patients. There was no correlation between the SP serum level and the scores obtained from urticaria evaluation questionnaires. SP among CU patients was higher than healthy subjects. SP was also higher among female, older and positive ASST patients. The SP value was not correlated with the severity of urticaria, angioedema. In conclusion, Using SP antagonist drugs could be a potential treatment for chronic urticaria.

Tachykinin NK1 receptor antagonist L-733,060 and substance P deletion exert neuroprotection through inhibiting oxidative stress and cell death after traumatic brain injury in mice.

Substance P (SP) is believed to play a role in traumatic brain injury (TBI), and the inhibition of binding of SP to the tachykinin neurokinin-1 receptor (NK1R) using NK1R antagonists had made favorable effects on TBI. Our current study addresses the functional roles and underlying mechanisms of SP and NK1R antagonist L-733,060 following TBI. Adult male wild type C57BL/6 J and SP knock out (SPKO) mice received a controlled cortical impact and outcome parameters were assessed. The results showed that TBI-induced motor and spatial memory deficits, lesion volume, brain water content and blood-brain barrier disruption were alleviated both in L-733,060-treated C57BL/6 J mice and vehicle-treated SPKO mice. L-733,060 treatment and SP deletion inhibited TBI-induced the release of cytochrome c from mitochondria to cytoplasm, activation of caspase-3, oxidative stress and neuroinflammation. Higher SP levels in serum and cortex were observed in wild type mice undergoing TBI relative to wild type sham group, but very little expression of cortical SP was detected in the SP-/- mice either TBI or not. Upregulation of NK1R expression after TBI was observed, and there was no significant difference between wild type and SPKO groups. in vitro, L-733,060 and SP deletion inhibited scratch injury-induced cell death, loss of mitochondrial membrane potential and reactive oxygen species (ROS) production following TBI. Together, the results of this study implicate a functional role for NK1-R antagonist L-733,060 and deletion of SP in TBI-induced neurological outcome, oxidative damage, neuroinflammation and cell death. Upregulation of NK1R maybe a consequence of TBI, independent of the levels of substance P. This study raises the possibility that targeting SP through its receptor NK1R or genetic deletion may have therapeutic efficacy in TBI.

Central Injection of Substance P Antagonizes the RF Amide-Related Peptide-3 Impacts on Hypothalamic KISS-1 and GnRH Gene Expressions in Male Wistar Rats

Background: Gonadotropin-inhibitory hormone and its mammalian orthologues (RFRP: RF amid related peptide) are known to inhibit the secretion of gonadotropins. In addition, substance P (SP) a member of tachykinin’s family is demonstrated that can increase the firing rate of kisspeptin/neurokinin B/dynorphin (KNDy) neurons and provokes the of secretion gonadotropins. In this experimental study we investigated the effects of co-administration of RFRP-3 and SP on the expression of KISS-1 and GnRH genes in male rats. Methods: forty-two mature Wistar rats were randomly allocated in 7 groups (n=6 in each group). Animals in each group intracerebroventricularly received either saline+DMSO, 1nmol SP, 5 nmol RFRP-3, 1nmol SP plus 5 nmol RFRP-3, 1 nmol SP plus10 nmol RF9 (RFRP-3 receptor antagonist), 1 nmol SP plus 1 nmol P234 (kisspeptin receptor antagonist) plus 5 nmol RFRP-3 or 1 nmol SP plus 5 nmol CP-96,345 (SP receptor antagonist) plus 5 nmol RFRP-3 in final volume of 3 µl. After two hours following injections hypothalamic samples were collected for evaluating the expression of target genes by real-time PCR technique. Results: Injections in SP and SP plus RF9 groups increase the expression of the both GnRH and KISS-1 genes (P&lt;0.05). Injections in RFRP-3 group and SP plus RFRP-3 plus SP antagonist group significantly decrease the expression of both GnRH and KISS-1 genes (P&lt;0.05). Injections of SP plus RFRP-3 group and SP plus RFRP-3 plus P234 group did not significantly change the expression of GnRH and KISS-1 genes. Conclusion: The results indicate that SP antagonizes the effects of RFRP-3 on the expression of Hypothalamic KISS-1 and GnRH genes.

Pemanfaatan Jamur Trichoderma sp Sebagai Antagonis Patogen Busuk Sulur Tanaman Buah Naga Merah (Hylocereus polyrhizus) Secara In Vitro

Utilization of Trichoderma sp fungi as pathogenic fungi antagonists in red dragon fruit plants (Hylocereus polyrhizus) in vitro. The purpose of this study was to identify foul pathogens of dragon fruit plants and then test the ability of Trichoderma sp antagonists to deciduous pathogens of red dragon fruit plants in vitro. The study was conducted from August to October 2016, The research was conducted at the Laboratory of Pest and Plant Disease Sciences, Faculty of Agriculture, Mulawarman University, Samarinda. Sampling of plants exposed to foul tendrils was carried out in Bukit Merdeka Village, Samboja District, Kutai Kartanegara Regency. There are two data observed in this study, primary data and secondary data. Primary data is data obtained directly from the source through direct field observations and laboratory observations and secondary data data obtained from interviews with farmers. The results showed that the pathogen that causes tendon rot in dragon fruit plants is the fungus Colletotrichum gloesporioides (penz. Ssaac). Trichoderma sp can inhibit the development of pathogens Colletotrichum gloesporioides (Penz.) Ssaac., With the highest average resistance of 71.85%.

Intra-articular injection of a substance P inhibitor affects gene expression in a joint contracture model.

Substance P (SP), a neurotransmitter released after injury, has been linked to deregulated tissue repair and fibrosis in musculoskeletal tissues and other organs. Although SP inhibition is an effective treatment for nausea, it has not been previously considered as an anti-fibrotic therapy. Although there are extensive medical records of individuals who have used SP antagonists, our analysis of human registry data revealed that patients receiving these antagonists and arthroplasty are exceedingly rare, thus precluding a clinical evaluation of their potential effects in the context of arthrofibrosis. Therefore, we pursued in vivo studies to assess the effect of SP inhibition early after injury on pro-fibrotic gene expression and contractures in an animal model of post-traumatic joint stiffening. Skeletally mature rabbits (n = 24) underwent surgically induced severe joint contracture, while injected with either fosaprepitant (a selective SP antagonist) or saline (control) early after surgery (3, 6, 12, and 24 h). Biomechanical testing revealed that differences in mean contracture angles between the groups were not statistically significant (P = 0.27), suggesting that the drug neither mitigates nor exacerbates joint contracture. However, microarray gene expression analysis revealed that mRNA levels for proteins related to cell signaling, pro-angiogenic, pro-inflammatory, and collagen matrix production were significantly different between control and fosaprepitant treated rabbits (P < 0.05). Hence, our study demonstrates that inhibition of SP alters expression of pro-fibrotic genes in vivo. This finding will motivate future studies to optimize interventions that target SP to reduce the formation of post-traumatic joint contractures.

The association between substance P and white matter integrity in medication-naive patients with major depressive disorder

Substance P (SP) has been implicated in major depressive disorder (MDD), with SP antagonists being studied as potential antidepressants. Although impaired neural plasticity is considered a key mechanism in MDD pathophysiology, the association between SP and brain structural changes in depression has not been investigated. We investigated the correlations between SP levels and white matter (WM) integrity in 42 medication-naive patients with MDD and 57 healthy controls (HCs). Plasma levels of SP were determined, and diffusion tensor imaging (DTI) was performed to investigate microstructural changes in WM tracts. In patients, negative correlations between SP levels and fractional anisotropy (FA) values of the forceps minor of the corpus callosum, and positive correlations between SP levels and radial diffusivity (RD) and mean diffusivity (MD) values of the right corticospinal tract (CST) were observed, with no significant correlations in HCs. Linear regression analyses showed SP levels to significantly predict FA values of the forceps minor, and RD and MD values of the right CST in patients, but not in HCs. We consider our findings to contribute to the neurobiological evidence on the association between SP and brain structural changes in depression, which may be related with the pathophysiology and treatment of MDD.

Capsaicin-induced rapid neutrophil leukocyte activation in the rat urinary bladder microcirculatory bed.

This study was initiated to investigate the involvement of neutrophil leukocyte activation in neurogenic inflammation, a process also involved in human urinary pathologies, elicited in the rat urinary bladder by the local administration of capsaicin, the archetypal TRPV1 agonist. The contribution of afferent nerves and sensory neuropeptides to leukocyte activation in the urinary bladder microcirculatory bed was examined. Following a 15-min topical application of capsaicin (50 μM), leukocyte-endothelial interactions were examined for an observation period of 45 min with intravital microscopy. Expression of adhesion molecules E-selectin and ICAM-1 implicated in these interactions was assessed by immunohistochemistry. Selective sensory denervation was performed by neonatal treatment with capsaicin. The role of the TRPV1 receptor and two sensory neuropeptides (CGRP and substance P [SP]) were studied using the selective antagonists capsazepine, CGRP8-37 and RP67580, respectively. Capsaicin induced rapid increases in leukocyte rolling and adhesion and increased the expression of E-selectin and ICAM-1 in the postcapillary venules. Sensory chemodenervation via capsaicin and also TRPV1 receptor antagonism effectively prevented these changes. A similar reduction was observed in leukocyte adhesion after topical application of CGRP8-34 or RP67580, but only CGRP8-34 reduced the capsaicin-evoked leukocyte rolling. Topical application of capsaicin induces early neurogenically mediated cellular microcirculatory inflammatory reactions via the activation of the TRPV1 receptor and the release of CGRP and SP from sensory nerves in the bladder. Co-administration of SP and CGRP receptor antagonists may ameliorate microcirculatory inflammatory changes elicited by capsaicin in the urinary bladder.

Pentapeptides for the treatment of small cell lung cancer: Optimisation by Nind-alkyl modification of the tryptophan side chain

The pentapeptide, tert-Prenyl4th-NH2 (DMePhe-DTrp-Phe-DTrp(N-tert-prenyl)-Leu-NH2), has recently been reported by our group to exhibit properties of substance P (SP) antagonist G against small cell lung cancer (SCLC). In this study, we undertook a systematic structure activity investigation to optimise this lead compound to improve its in vitro anti-tumour activity and biocompatibility. A series of d-tryptophan (D-Trp) derivatives were synthesised, with a range of aliphatic N-alkyl chains (methyl to pentyl) on the indole nitrogen (Nind). These were incorporated into the pentapeptide sequence by substitution of the Nind-tert-prenylated D-Trp 4th residue with the Nind-alkylated D-Trp derivatives. These pentapeptides were significantly more potent than tert-Prenyl4th-NH2, with the Nind-butyl modification generating the most cytotoxic peptides. Compared to tert-Prenyl4th-NH2, a single butyl modification on the 4th D-Trp residue (Butyl4th-NH2) showed a ∼3 fold enhancement in cytotoxicity in either the chemo-naive H69 or the DMS79 (originating from a patient treated with chemotherapeutics and radiation therapy) SCLC cell lines. In addition, the di-butylated sequence on the 2nd and 4th D-Trp residues (Butyl2nd,4th-NH2) gave ∼4.5 times higher cytotoxicity against the H69 cell line and a ∼2 fold increase against the DMS79 cell line, compared to tert-Prenyl4th-NH2. The favoured position for butyl modification was the 4th D-Trp residue, as the Butyl2nd-NH2 peptide gave lower cytotoxicity on both cell lines. Butylated peptide sequences, when exposed to neat mouse plasma for 24 h at 37 °C, were found to resist degradation with >80% remaining intact compared to ∼58% for tert-Prenyl4th-NH2. The degradation pathway in plasma occurs via de-amidation of the C-terminus, confirmed by mass spectrometry and RP-HPLC analysis. The butyl modification also conferred resistance to metabolism when tested using S9 liver fraction from mouse. The optimum analogue responsive against the DMS79 cell line was the Butyl4th-NH2 pentapeptide, which revealed a concentration dependent increase in apoptosis: the level of late apoptotic cells rose from ∼36% at 2 μM to ∼96% at 6 μM, as determined by flow cytometry, compared to the unmodified peptide that showed no such effect. Concluding, the butyl substitutions offered the best perspective for high cytotoxicity, induction of apoptosis and metabolic compatibility thereby comprising an improved broad spectrum SP antagonist candidate for treatment of SCLC.

Activation of NPFFR2 leads to hyperalgesia through the spinal inflammatory mediator CGRP in mice

Neuropeptide FF (NPFF) is recognized as an opioid modulating peptide that regulates morphine-induced analgesia. The aim of this study was to delineate the role of NPFFR2 in pain transmission. We found the expression levels of NPFF and NPFFR2 were increased in the lumbar dorsal horn of animals with CFA- and carrageenan-induced inflammation and both NPFFR2 over-expressing transgenic (NPFFR2-Tg) and NPFFR2 agonist-treated mice displayed hyperalgesia. BOLD signals from functional MRI showed that NPFFR2-Tg mice exhibited increased activation of pain-related brain regions after painful stimulation when compared to WT mice. Inflammatory mediators within the spinal cord, calcitonin gene-related peptide (CGRP) and substance P (SP), were up-regulated in NPFFR2-Tg and chronic NPFFR2 agonist-treated mice. In DRG cultures, treatment with an NPFFR2 agonist induced the expression and release of CGRP, an action which was blocked by NPFFR2 siRNA. Furthermore, treatment with a CGRP antagonist ameliorated the pain hyperalgesia in NPFFR2-Tg mice, returning the pain threshold to a control level. However, treatment with a SP antagonist reduced the pain responses in both WT and NPFFR2-Tg mice and did not suppress pain hypersensitivity in NPFFR2-Tg mice. Together, these results demonstrate that NPFFR2 activation modulates pain transmission by up-regulating the pain mediator CGRP, leading to hyperalgesia.

The Effect of Substance P on an Intervertebral Disc Rat Organ Culture Model.

Laboratory study. Evaluate the effect of substance P (SP) on an intervertebral disc rat organ culture model. Monolayer cell experiments have demonstrated that exposure intervertebral disc tissue cells to SP leads to upregulation in inflammatory cytokine expression; however, this has not been evaluated in a more complex organ culture model. Forty-eight intervertebral discs from eight rats were used in an organ culture model. Intervertebral discs were divided into three groups: control, SP-treated group, and a group treated with an SP antagonist followed by SP. Cytokine antibody array was used to quantify expression patterns, which were confirmed using ELISA and real-time polymerase chain reaction. The cytokine array demonstrated a 3.40 ± 0.59-fold increase in interleukin 6 (IL-6) expression in the SP group (P = 0.004), and the effect of SP was mitigated by the SP antagonist (P = 0.03). These results were verified as ELISA demonstrated a significant difference in the IL-6 level between the control group and SP group (0.73 vs. 5.80 ng/mL, P < 0.001), and there was a significant difference in the IL-6 level between the SP and the SP antagonist group (5.80 vs. 4.02 ng/mL, P = 0.01). Similarly, the real-time polymerase chain reaction demonstrated that the discs treated with SP had a 4.77-fold increase in IL-6 levels (P = 0.01) compared to controls, and a significantly greater increase in IL-6 levels between the intervertebral discs in the SP group and those in the SP antagonist group versus control (4.77 vs. 1.57, P = 0.02). SP lead to the activation of an inflammatory pathway by increasing expression of IL-6 in an intervertebral disc organ culture model. These results provide evidence that SP may be an important factor in the link between intervertebral disc degeneration and low back pain. N/A.

Substance P Promotes the Proliferation, but Inhibits Differentiation and Mineralization of Osteoblasts from Rats with Spinal Cord Injury via RANKL/OPG System.

Spinal cord injury (SCI) causes a significant amount of bone loss, which results in osteoporosis (OP). The neuropeptide substance P (SP) and SP receptors may play important roles in the pathogenesis of OP after SCI. To identify the roles of SP in the bone marrow mesenchymal stem cell derived osteoblasts (BMSC-OB) in SCI rats, we investigated the expression of neurokinin-1 receptors (NK1R) in BMSC-OB and the effects of SP on bone formation by development of BMSC-OB cultures. Sixty young male Sprague-Dawley rats were randomized into two groups: SHAM and SCI. The expression of NK1R protein in BMSC-OB was observed using immunohistochemistry and Western blot analysis. The dose- and time-dependent effects of SP on the proliferation, differentiation and mineralization of BMSC-OB and the expression of osteoblastic markers by in vitro experiments. The expression of NK1R in BMSC-OB was observed on plasma membranes and in cytoplasm. One week after osteogenic differentiation, the expression of NK1R was significantly increased after SCI at mRNA and protein levels. However, this difference was gradually attenuated at 2 or 3 weeks later. SP have the function to enhance cell proliferation, inhibite cell differentiation and mineralization at a proper concentration and incubation time, and this effect would be inhibited by adding SP or NK1R antagonist. The expression of RANKL/OPG was significantly increased in tibiae after SCI. Similarly, the RANKL/OPG expression in SCI rats was significantly increased when treating with 10−8 M SP. SP plays a very important role in the pathogenesis of OP after SCI. The direct effect of SP may lead to increased bone resorption through the RANKL/OPG axis after SCI. In addition, high expression of SP also results in the suppression of osteogenesis in SCI rats. Then, the balance between bone resorption and bone formation was broken and finally osteoporosis occurred.

Serum substance P levels are associated with severity and mortality in patients with severe traumatic brain injury.

IntroductionSubstance P (SP) is a member of the tachykinin family of neuropeptides, which are widely distributed throughout the central nervous system (CNS) and actively involved in inflammatory processes. SP is released early following acute injury to the CNS, promoting a neurogenic inflammatory response characterized by an increase in the permeability of the blood–brain barrier and the development of vasogenic edema. High levels of SP could lead to an exacerbated inflammatory response that could be fatal for patients with traumatic brain injury (TBI). Thus, the main goal of the present study was to determine whether serum SP levels are associated with injury severity and mortality in patients with severe TBI.MethodsThis multicenter, observational, prospective study was carried out in six Spanish intensive care units and included patients with Glasgow Coma Scale (GCS) scores ≤8. Patients with an Injury Severity Score ≥10 in non-cranial aspects were excluded. Blood samples were collected on day 1 of TBI to measure serum SP levels. The endpoint was 30-day mortality.ResultsWe found higher serum SP levels (P =0.002) in non-surviving patients (n =27) than in surviving patients (n =73). The area under the curve for serum SP levels with regard to predicting 30-day mortality was 0.70 (95% confidence interval (CI), 0.60 to 0.79; P <0.001). Survival analysis showed that patients with serum SP levels >299 pg/ml had higher 30-day mortality than patients with lower levels (hazard ratio =3.7; 95% CI, 1.75 to 7.94; P <0.001). Multiple binomial logistic regression analysis showed that serum SP levels >299 pg/ml were associated with 30-day mortality when we controlled for APACHE II score and Marshall computed tomography lesion classification (odds ratio (OR) =5.97; 95% CI, 1.432 to 24.851; P =0.01) and for GCS score and age (OR =5.71; 95% CI, 1.461 to 22.280; P =0.01). We found a negative association between serum SP levels and GCS score (Spearman’s ρ = −0.22; P =0.03).ConclusionsWe report, for the first time to our knowledge, that serum SP levels were associated with injury severity and mortality in patients with severe TBI. These results open the possibility that SP antagonists may be useful in the treatment of patients with severe TBI.

Severing Corneal Nerves in One Eye Induces Sympathetic Loss of Immune Privilege and Promotes Rejection of Future Corneal Allografts Placed in Either Eye

Less than 10% of corneal allografts undergo rejection even though HLA matching is not performed. However, second corneal transplants experience a threefold increase in rejection, which is not due to prior sensitization to histocompatibility antigens shared by the first and second transplants since corneal grafts are selected at random without histocompatibility matching. Using a mouse model of penetrating keratoplasty, we found that 50% of the initial corneal transplants survived, yet 100% of the subsequent corneal allografts (unrelated to the first graft) placed in the opposite eye underwent rejection. The severing of corneal nerves that occurs during surgery induced substance P (SP) secretion in both eyes, which disabled T regulatory cells that are required for allograft survival. Administration of an SP antagonist restored immune privilege and promoted graft survival. Thus, corneal surgery produces a sympathetic response that permanently abolishes immune privilege of subsequent corneal allografts, even those placed in the opposite eye and expressing a completely different array of foreign histocompatibility antigens from the first corneal graft.

NK-1 Antagonists and Itch.

Substance P (SP) is an important mediator of pro-inflammatory mechanisms in the skin. It targets multiple cells such as keratinocytes, mast cells, and fibroblasts which are involved in the cutaneous generation of pruritus. This suggests that SP is an interesting target for therapy. In fact, in recent case reports and case series, SP antagonists demonstrated a significant antipruritic effect in acute and chronic pruritus such as drug-induced pruritus, paraneoplastic pruritus, prurigo nodularis, cutaneous T-cell lymphoma, and brachioradial pruritus.