Neurokinin Research Articles

English

BACKGROUND Chemotherapy-induced nausea and vomiting (CINV) is a frequent and feared adverse effect of cancer chemotherapy. International guidelines recommend combinations of 5-hydroxytryptamine type 3 (5-HT3) receptor antagonists, dexamethasone, and/or neurokinin-1 (NK1) receptor antagonists for the control of CINV in patients receiving highly emetogenic chemotherapy (HEC) as a part of their treatment. Even though, nausea in delayed period is less controlled and poses a major concern for these patients. METHODS This open label, prospective study was conducted in a rural medical college in Etawah District in Uttar Pradesh, India from November 2017 to November 2018 over a period of 1 year to observe the efficacy of low dose (5 mg OD) olanzapine in combination with standard anti-emetic regimen for the prevention of CINV. Olanzapine is a food and drug administration (FDA) approved antipsychotic drug that has anti-emetic activity and has shown to improve CINV. Low dose olanzapine along with a standard combination of ondansetron, dexamethasone and aprepitant was given to patients receiving highly emetogenic chemotherapy (Cisplatin >70 mg/m2 or doxorubicin-cyclophosphamide combination). CINV was assessed using common toxicity criteria of adverse events (CTCAE) version 5.0. RESULTS Complete response to nausea was observed in 90.90 %, 60.60 % and 54.54 % in acute, delayed and overall period respectively. Complete response to vomiting was observed in 96.96 %, 69.69 % and 66.66 % in acute, delayed and overall period respectively. Complete response to Grade-2 (or above) nausea was observed in 96.96 %, 93.93 % and 90.90 % in acute, delayed and overall period, respectively. Daytime Grade -3 somnolence which was seen in 2/33 patients (6.06 %) was attributable to olanzapine. Patients receiving olanzapine were more likely to have complete response of nausea and emesis in the early, late, and overall assessment periods especially of higher grade (G2 and G3). CONCLUSIONS The authors concluded that low dose olanzapine 5 mg OD combined with an NK1- receptor antagonist, a 5-HT3–receptor antagonist, and dexamethasone is safe and efficacious in the prevention of CINV in patients receiving HEC. KEYWORDS Olanzapine, Low Dose, CINV, HEC

A Pragmatic Study Evaluating NEPA Versus Aprepitant for Prevention of Chemotherapy-Induced Nausea and Vomiting in Patients Receiving Moderately Emetogenic Chemotherapy.

BackgroundNeurokinin (NK) 1 receptor antagonists (RAs), administered in combination with a 5‐hydroxytryptamine‐3 (5‐HT3) RA and dexamethasone (DEX), have demonstrated clear improvements in chemotherapy‐induced nausea and vomiting (CINV) prevention over a 5‐HT3RA plus DEX. However, studies comparing the NK1RAs in the class are lacking. A fixed combination of a highly selective NK1RA, netupitant, and the 5‐HT3RA, palonosetron (NEPA), simultaneously targets two critical antiemetic pathways, thereby offering a simple convenient antiemetic with long‐lasting protection from CINV. This study is the first head‐to‐head NK1RA comparative study in patients receiving anthracycline cyclophosphamide (AC) and non‐AC moderately emetogenic chemotherapy (MEC).Materials and MethodsThis was a pragmatic, multicenter, randomized, single‐cycle, open‐label, prospective study designed to demonstrate noninferiority of single‐dose NEPA to a 3‐day aprepitant regimen in preventing CINV in chemotherapy‐naive patients receiving AC/non‐AC MEC in a real‐life setting. The primary efficacy endpoint was complete response (no emesis/no rescue) during the overall (0–120 hour) phase. Noninferiority was achieved if the lower limit of the 95% confidence interval (CI) of the difference between NEPA and the aprepitant group was greater than the noninferiority margin set at −10%.ResultsNoninferiority of NEPA versus aprepitant was demonstrated (risk difference 9.2%; 95% CI, −2.3% to 20.7%); the overall complete response rate was numerically higher for NEPA (64.9%) than aprepitant (54.1%). Secondary endpoints also revealed numerically higher rates for NEPA than aprepitant.ConclusionThis pragmatic study in patients with cancer receiving AC and non‐AC MEC revealed that a single dose of oral NEPA plus DEX was at least as effective as a 3‐day aprepitant regimen, with indication of a potential efficacy benefit for NEPA.Implications for PracticeIn the absence of comparative neurokinin 1 (NK1) receptor antagonist (RA) studies, guideline committees and clinicians consider NK1RA agents to be interchangeable and equivalent. This is the first head‐to‐head study comparing one NK1RA (oral netupitant/palonosetron [NEPA]) versus another (aprepitant) in patients receiving anthracycline cyclophosphamide (AC) and non‐AC moderately emetogenic chemotherapy. Noninferiority of NEPA versus the aprepitant regimen was demonstrated; the overall complete response (no emesis and no rescue use) rate was numerically higher for NEPA (65%) than aprepitant (54%). As a single‐dose combination antiemetic, NEPA not only simplifies dosing but may offer a potential efficacy benefit over the current standard‐of‐care.

Netupitant/Palonosetron: A Review in Chemotherapy-Induced Nausea and Vomiting.

Netupitant/palonosetron (NEPA; Akynzeo®), available in oral and intravenous (IV) formulations, is a fixed-dose combination of the neurokinin 1 (NK1) receptor antagonist netupitant (or the prodrug, fosnetupitant, in the IV formulation) and the second-generation serotonin 3 (5-HT3) receptor antagonist palonosetron. Administered as a single dose, (fos)netupitant/palonosetron (in combination with dexamethasone) is indicated for the prevention of acute and delayed chemotherapy-induced nausea and vomiting (CINV) in adults. In clinical trials, (fos)netupitant/palonosetron plus dexamethasone was associated with high complete response rates (no emesis and no rescue medication) in the acute, delayed and overall phases in patients receiving highly or moderately emetogenic chemotherapy, with efficacy maintained over multiple cycles. Further, oral netupitant/palonosetron was found to be superior to palonosetron and non-inferior to aprepitant plus granisetron in preventing CINV in individual trials. Both the oral and IV formulations of the drug combination are well tolerated. The fixed-dose combination is concordant with guideline recommendations and provides a simple and convenient option for prophylaxis against acute and delayed CINV in patients receiving highly or moderately emetogenic chemotherapy.Supplementary InformationThe online version contains supplementary material available at 10.1007/s40265-021-01558-2.

Neurokinin-1 Antagonists for Postoperative Nausea and Vomiting.

Postoperative nausea and vomiting (PONV) are the second most frequent adverse events after surgery second only to postoperative pain. Despite the advances in antiemetics and implementation of multimodal prophylactic interventions, the clinical management of PONV remains problematic. Neurokinin-1 (NK-1) receptor is a tachykinin receptor found throughout the central and peripheral nervous systems, with a particular affinity towards substance P. NK-1 receptors interact with several parts of the neuronal pathway for nausea and vomiting. This includes the chemoreceptor trigger zone, the gastrointestinal tract, and dorsal motor nucleus of the vagus. NK-1 antagonists are thought to prevent nausea and vomiting by downregulating the emetogenic signals at those points. As more head-to-head trials are conducted between the various anti-emetics, there is emerging evidence that NK-1 antagonists may be more effective in preventing PONV than several other antiemetics currently in use. In this review, we will discuss the pharmacology of NK-1 antagonists, their efficacy in clinical practice, and how they could fit into the framework of PONV management.

Increased expression of transient receptor potential channels and neurogenic factors associates with cough severity in a guinea pig model

BackgroundPrevious studies suggest that transient receptor potential (TRP) channels and neurogenic inflammation may be involved in idiopathic pulmonary fibrosis (IPF)-related high cough sensitivity, although the details of mechanism are largely unknown. Here, we aimed to further explore the potential mechanism involved in IPF-related high cough sensitivity to capsaicin challenge in a guinea pig model of pulmonary fibrosis induced by bleomycin.MethodsWestern blotting and real-time quantitative polymerase chain reaction (RT-qPCR) were employed to measure the expression of TRP channel subfamily A, member 1 (TRPA1) and TRP vanilloid 1 (TRPV1), which may be involved in the cough reflex pathway. Immunohistochemical analysis and RT-qPCR were used to detect the expression of neuropeptides substance P (SP), Neurokinin-1 receptor (NK1R), and calcitonin gene-related peptide (CGRP) in lung tissues. Concentrations of nerve growth factor (NGF), SP, neurokinin A (NKA), neurokinin B (NKB), and brain-derived neurotrophic factor (BDNF) in lung tissue homogenates were measured by ELISA.ResultsCough sensitivity to capsaicin was significantly higher in the model group than that of the sham group. RT-qPCR and immunohistochemical analysis showed that the expression of TRPA1 and TRPV1 in the jugular ganglion and nodal ganglion, and SP, NK1R, and CGRP in lung tissue was significantly higher in the model group than the control group. In addition, expression of TRP and neurogenic factors was positively correlated with cough sensitivity of the experimental animals.ConclusionUp-regulated expression of TRPA1 and TRPV1 in the cough reflex pathway and neurogenic inflammation might contribute to the IPF-related high cough sensitivity in guinea pig model.

The expanded effects of sevoflurane on the nervous system: the harmful effect of residual concentration of sevoflurane on the respiratory system through neurogenic inflammation.

Neurogenic inflammation caused by sevoflurane may not only limite to the nervous system, but also expand to the respiratory system. The purpose of this study was to investigate the expression changes of transient receptor potential vanilloid 1 (TRPV1), neurokinin A (NKA), neurokinin B (NKB), calcitonin gene related peptide (CGRP) and substance P (SP) in 14, 21 and 42-day-old rats after inhaling 0.4% sevoflurane, in order to evaluate whether the residual sevoflurane be harmful to the respiratory system through neurogenic inflammation. The anesthetic inhalation device was designed to allow 14, 21 and 42-day-old rats inhale 0.4% sevoflurane, while rats in the control group inhaled 40% O2 for 1h. Rats in the antagonist group inhaled 0.4% sevoflurane or 40% O2 for 1h after Capsazepine (CPZ) pretreatment. The expression of TRPV1 in lung tissue was detected by western blot, and the expression of NKA, NKB, CGRP and SP in trachea was detected by immunohistochemistry. After inhaling 0.4% sevoflurane, the expression of TRPV1 in lung tissue of 14 and 21-day-old rats was significantly higher than that of the control group, as well as increased the expression of CGRP and SP in the trachea of 14-day-old rats and NKA, NKB, CGRP and SP in the trachea of 21-day-old rats. CPZ pretreatment could antagonize these effects. Residual sevoflurane during resuscitation of inhalation anesthesia could induce neurogenic inflammation by activating TRPV1, which damaged to the developing respiratory system, but has no significant effect on the respiratory system in adulthood.

Effects of neurokinin 3 receptor antagonist fezolinetant on hot flash-like symptoms in ovariectomized rats

The majority of women experience vasomotor symptoms (VMS), such as hot flashes and night sweats, during the menopausal transition. Recent evidence strongly suggests a connection between neurokinin 3 (NK3) receptor signaling and VMS associated with menopause. The NK3 receptor antagonist fezolinetant is currently in phase 3 development for treatment of moderate to severe VMS associated with menopause. We investigated the pharmacological effects of repeated administration of fezolinetant on levels of sex hormones and gonadotropins, neuronal activity in the hypothalamus, and skin temperature as an index of hot flash-like symptoms in ovariectomized rats as a model of menopause. Ovariectomized rats exhibited several typical menopausal symptoms: hyperphagia, increased body weight, significantly decreased plasma estradiol levels, increased luteinizing hormone (LH) and follicle-stimulating hormone (FSH) levels, and significantly increased skin temperature. Increased c-Fos expression (an indirect marker of neuronal activity) in median preoptic nucleus (MnPO) hypothalamic neurons was also observed in ovariectomized rats. Repeated oral administration of fezolinetant (1–10 mg/kg, twice daily) for 1 week dose-dependently reduced plasma LH levels without affecting estradiol or FSH levels, inhibited the activation of MnPO neurons, and attenuated hot flash-like symptoms. In addition, fezolinetant dose-dependently reduced hyperphagia and weight gain in ovariectomized rats. These preclinical findings suggest that fezolinetant attenuates hot flash-like symptoms via inhibition of neuronal activity in the MnPO of ovariectomized rats and provides further support for the ongoing clinical development of fezolinetant for the treatment of VMS associated with menopause.

Impact of the Oncology Care Model on use of bone supportive medications, antiemetics, and growth factors.

1517 Background: The Oncology Care Model (OCM) is a voluntary, episode-based alternative payment model for cancer care launched by the Centers for Medicare & Medicaid Services in July 2016. OCM incentivizes participating practices to reduce spending during chemotherapy treatment while maintaining quality of care. We evaluated the impact of OCM on the use of costly supportive care medications. Methods: Using 100% Medicare claims (2013-2019), we evaluated use of outpatient supportive care medications during chemotherapy episodes assigned to OCM practices (n = 186) or propensity-matched comparison practices (n = 534). For bone supportive medications, we evaluated use of bisphosphonates and/or denosumab in beneficiaries with bone metastases from breast, lung, or prostate cancer. For anti-emetic drugs, we evaluated prophylactic use of neurokinin-1 (NK1) antagonists and long-acting (LA) serotonin antagonists. For white blood cell growth factors (GCSFs), we evaluated prophylactic use in beneficiaries starting chemotherapy for breast, lung, or colorectal cancer; we separately evaluated use of biosimilar (vs originator) filgrastim. Analyses employed the difference-in-differences (DID) approach, excepting the filgrastim biosimilar analysis where we assessed the adoption trend. Results: There was no OCM impact on receipt of any bone supportive medication (denosumab or bisphosphonate) among beneficiaries with bone metastases; however, OCM led to a relative decrease in use of denosumab for breast cancer (DID = -5.0 percentage points [90% CI -7.1, -2.8]), prostate cancer (-4.0 percentage points [90% CI -5.9, -2.2]), and lung cancer (-4.1 percentage points [90% CI -7.4, -0.9]). In beneficiaries starting chemotherapy regimens with high or moderate emetic risk, OCM led to reductions in prophylactic use of NK1 antagonists and LA serotonin antagonists (e.g. 6.0 percentage point reduction in use of NK1 antagonists during high emetic risk chemotherapy [90% CI -9.0, -3.1]); there was no impact on antiemetic use during low emetic risk chemotherapy. There was no OCM impact on use of prophylactic WBC growth factors among beneficiaries receiving chemotherapy with high risk for febrile neutropenia (FN). Among beneficiaries receiving chemotherapy with intermediate risk for FN, OCM led to a 7.6 percentage point reduction in prophylactic GCSF use for patients with breast cancer (90% CI -12.6, -2.7); however, there was no OCM impact on prophylactic GCSF use in patients with lung or colorectal cancer. Among beneficiaries receiving filgrastim, OCM led to faster adoption of biosimilar vs. originator filgrastim (differential trend estimate 2.6%, 90% CI 1.0, 4.4). Conclusions: OCM led to reduced use of some high cost supportive care medications, with patterns suggesting more value-conscious care. Alternative payment models have potential to drive value-based changes in medication use during cancer care.

A phase III, randomized, double-blind, multicenter, active control study of fosnetupitant for the prevention of chemotherapy-induced nausea and vomiting (CINV) in patients receiving cisplatin-based highly emetogenic chemotherapy (HEC): CONSOLE.

12099 Background: Fosnetupitant (FN) is a phosphorylated pro-drug of netupitant that has high binding affinity for the neurokinin-1 (NK-1) receptor and a long half-life of 70 h. This phase 3 study is the first head-to-head study to compare two NK-1 receptor antagonists, FN and fosaprepitant (FA), in combination with palonosetron and dexamethasone for the prevention of chemotherapy-induced nausea and vomiting (CINV) in patients receiving highly emetogenic chemotherapy (JapicCTI-194611). Methods: Patients scheduled to receive cisplatin (≥70 mg/m2) -based chemotherapy were randomly assigned 1:1 to receive FN 235 mg or FA 150 mg, in combination with palonosetron 0.75 mg and dexamethasone (9.9 mg on day 1, 6.6 mg on days 2-4). The stratification factors were sex, age category (<55 vs. ≥55 years), and site. The primary endpoint was the complete response (CR; no emetic events and no rescue medication) rate, stratified by sex and age category, during the overall phase (0-120 h) to show the non-inferiority (margin, -10%) of FN to FA. The secondary endpoints were: CR rate, complete protection rate, total control rate, no nausea rate, no emetic events rate in each period [i.e., acute (0-24 h), delayed (24-120 h), overall, 0-168 h and 120-168 h], time to treatment failure, and safety, including injection site reactions (ISRs). Assessment of efficacy was continued until 168 h after the initiation of cisplatin. Some eligible patients were evaluated for safety and efficacy of FN for up to four cycles. Results: Between February 2019 and March 2020, total 795 patients were enrolled in the study. The study drug was administered to 785 patients (n=392 in FN vs. n=393 in FA), and all of them were evaluated for efficacy and safety. Baseline characteristics were generally balanced between the two groups. The adjusted overall CR rate was 75.2% in FN vs. 71.0% in FA [MH common risk difference, 4.1%; 95% CI, -2.1% to 10.3%), thus demonstrating non-inferiority of FN to FA. Regarding the other secondary endpoints of efficacy until 168 h, FN was favorable against FA, especially the CR rate during 0-168 h (73.2% in FN vs. 66.9% in FA) (Table). The incidence rates of treatment-related adverse events were 22.2% in FN vs. 25.4% in FA, whereas those of ISRs with any cause or with treatment-related were 11.0% or 0.3% in FN vs 20.6% or 3.6% in FA, respectively ( p<0.001). Conclusions: FN demonstrated non-inferiority to FA, with a favorable safety profile and lower risk for ISRs. For the period beyond 120 h after initiation of chemotherapy, FN may have the potential to improve the prevention of “beyond delayed” CINV. Clinical trial information: JapicCTI-194611. [Table: see text]

Randomized Controlled Trial of Neurokinin 3 Receptor Antagonist Fezolinetant for Treatment of Polycystic Ovary Syndrome.

ContextPolycystic ovary syndrome (PCOS), a highly prevalent endocrine disorder characterized by hyperandrogenism, is the leading cause of anovulatory infertility.ObjectiveThis proof-of-concept study evaluated clinical efficacy and safety of the neurokinin 3 (NK3) receptor antagonist fezolinetant in PCOS.MethodsThis was a phase 2a, randomized, double-blind, placebo-controlled, multicenter study (EudraCT 2014-004409-34). The study was conducted at 5 European clinical centers. Women with PCOS participated in the study. Interventions included fezolinetant 60 or 180 mg/day or placebo for 12 weeks. The primary efficacy end point was change in total testosterone. Gonadotropins, ovarian hormones, safety and tolerability were also assessed.ResultsSeventy-three women were randomly assigned, and 64 participants completed the study. Adjusted mean (SE) changes in total testosterone from baseline to week 12 for fezolinetant 180 and 60 mg/day were −0.80 (0.13) and −0.39 (0.12) nmol/L vs −0.05 (0.10) nmol/L with placebo (P < .001 and P < .05, respectively). Adjusted mean (SE) changes from baseline in luteinizing hormone (LH) for fezolinetant 180 and 60 mg/d were −10.17 (1.28) and −8.21 (1.18) vs −3.16 (1.04) IU/L with placebo (P < .001 and P = .002); corresponding changes in follicle-stimulating hormone (FSH) were −1.46 (0.32) and −0.92 (0.30) vs −0.57 (0.26) IU/L (P = .03 and P = .38), underpinning a dose-dependent decrease in the LH-to-FSH ratio vs placebo (P < .001). Circulating levels of progesterone and estradiol did not change significantly vs placebo (P > .10). Fezolinetant was well tolerated.ConclusionFezolinetant had a sustained effect to suppress hyperandrogenism and reduce the LH-to-FSH ratio in women with PCOS.

Immunohistochemical Expression of Neurokinin-A and Interleukin-8 in the Bronchial Epithelium of Horses with Severe Equine Asthma Syndrome during Asymptomatic, Exacerbation, and Remission Phase.

Simple SummarySevere equine asthma (EA) syndrome, formerly termed Recurrent Airway Obstruction (RAO) or heaves, is one of the most common respiratory diseases in adult horses and a frequent cause of poor equine performance. The affected animals may show periods of clinical remission followed by periods of exacerbation over months to years. Therefore, the aim of the present study was to investigate the histological features, and the Neurokinin-A (NKA) and Interleukin-8 (IL-8) immunoreactivity on bronchoscopic biopsies in horses, obtained during different phases of the disease (asymptomatic, exacerbation and remission). Histological samples of EA-affected horses appeared significantly different from those of non-EA-affected horses (control group) throughout the experimental phase, from inclusion to exacerbation and remission, and intensity of NKA immunopositivity of horses with severe EA was significantly higher than that of control horses in late exacerbation and in remission phase. No significant difference between horses with severe EA in each phase and control horses was noticed for IL-8 immunoreactivity. Moreover, no influence of bronchial sampling position on histological and immunohistochemistry results was found, and it suggests that bronchial structural and functional modification during severe equine asthma tends to be distributed homogeneously throughout the respiratory tree.Severe equine asthma (EA) syndrome is a chronic obstructive disease characterized by exaggerated contraction, inflammation, and structural alteration of the airways in adult horses, when exposed to airborne molds and particulate material. However, little is known about the relationship between the degree and type of inflammation on one hand, and the severity of the disease and the response to treatment on the other. Furthermore, to date, very few studies evaluate the diagnostic value of histology and immunohistochemical features of endoscopic biopsies on subjects with severe equine asthma. To investigate the expression of two inflammatory markers (NKA and IL-8) before, during, and after the exacerbation of severe EA, a histological and immunohistochemical study was carried out on a series of biopsy samples collected by bronchoscopy from six EA-affected horses subjected to process exacerbation through environmental stimuli and then to pharmacological treatment. The application of a histological biopsy scoring system revealed a significant difference between control cases and the EA-affected horses in all experimental phases (asymptomatic, early exacerbation phase, late exacerbation phase, and remission phase). For immunohistochemistry (IHC), only the intensity of NKA positivity increases significantly between control horses and the EA horses at late exacerbation and remission phases. In EA-affected horses, a difference was detected by comparing histology between asymptomatic and remission phase, meanwhile, NKA and IL-8 showed no differences between the experimental phases. Based on these results we can assert that: (1) The endoscopic biopsies generate reliable and homogeneous samples in the entire bronchial tree; (2) the clinical improvement associated with treatment is characterized by a significant worsening of the histological findings; and (3) the NKA immunopositivity seems to increase significantly rather than decrease, as one would have expected, after pharmacological treatment. Further studies are necessary both to implement the number of samples and to use other markers of inflammation to characterize the potential role of cytokines in the diagnosis and therapeutic approach of severe equine asthma.

Neurokinin A blocks the ABCA1 channel to promote IL-10-dependent mast cell regulation

Abstract Cutaneous mast cells (MCs) reside in close proximity to peripheral sensory nerve fibers and are susceptible to regulation by neuropeptides. The tachykinin family member, Neurokinin A (NKA) binds with highest affinity to the Neurokinin 2 Receptor, expressed on MCs. MCs are poised to respond to NKA, but its role in the MC biology is, to our knowledge, under-explored. The objective of this study was to evaluate the effects of NKA on bone marrow (BM) MCs and peritoneal (P)MCs in vitro and in the murine model of passive cutaneous anaphylaxis (PCA) in vivo. Neurokinin A inhibited FceRI-initiated phosphorylation and nuclear localization of STAT5, and release of TNF and IL-13 in an IL-10-dependent manner. NKA affected the MC secretome, abrogating ABCA1-dependent release of the cysteine protease, calpain. Extracellular calpain, in turn, degraded IL-10. In vivo, NKA administration reduced PCA, inhibiting edema, and induction of inflammatory cytokines and in a manner that relied on MC derived-IL-10. Likewise, direct inhibition of the ABCA1 phenocopied the effects of NKA, reducing IgE-initiated MC responses in vitro and in vivo. In conclusion, NKA minimizes IgE-initiated inflammation though an IL-10-dependent mechanism and inhibits ABCA1-dependent release of the IL-10 degrading enzyme, calpain. This study illuminates a novel tier of neuropeptide mediated MC regulation through the ABCA1. Strategies interfering with the ABCA1 may be promising therapeutics for targeting MCs in cutaneous inflammatory diseases.

Angiotensin (1-7) Attenuates the Nociceptive Behavior Induced by Substance P and NMDA via Spinal MAS1.

The intrathecal (i.t.) injection of substance P (SP) and N-methyl-D-aspartate (NMDA) induce transient nociceptive response by activating neurokinin (NK) 1 and NMDA receptors, respectively. We have recently reported that angiotensin (Ang) (1-7), an N-terminal fragment of Ang II, could alleviate several types of pain including neuropathic and inflammatory pain by activating spinal MAS1. Here, we investigated whether Ang (1-7) can inhibit the SP- and NMDA-induced nociceptive response. The nociceptive response induced by an i.t. injection of SP or NMDA was assessed by measuring the duration of hindlimb scratching directed toward the flank, biting and/or licking of the hindpaw or the tail for 5 min. Localization of MAS1 and either NK1 or NMDA receptors in the lumbar superficial dorsal horn was determined by immunohistochemical observation. The nociceptive response induced by SP and NMDA was attenuated by the i.t. co-administration of Ang (1-7) (0.03-3 pmol) in a dose-dependent manner. The inhibitory effects of Ang (1-7) (3 pmol) were attenuated by A779 (100 pmol), a MAS1 antagonist. Moreover, immunohistochemical analysis showed that spinal MAS1 co-localized with NK1 receptors and NMDA receptors on cells in the dorsal horn. Taken together, the i.t. injection of Ang (1-7) attenuated the nociceptive response induced by SP and NMDA via spinal MAS1, which co-localized with NK1 and NMDA receptors. Thus, the spinal Ang (1-7)/MAS1 pathway could represent a therapeutic target to effectively attenuate spinal pain transmission caused by the activation of NK1 or NMDA receptors.

Substance P, a Neuropeptide, Promotes Wound Healing via Neurokinin-1 Receptor.

Substance P (SP), an endogenous neuropeptide, mediates intracellular signaling, mainly through a tachykinin receptor. The tachykinin receptors family consists of neurokinin-1 (NK-1), neurokinin-2 (NK-2), and neurokinin-3 receptors. Our previous studies on SP have shown its wound healing potentials. But the exact mechanism of wound healing by SP is not exactly known. In view of this, the present study was aimed at evaluating the in vitro wound healing effect of SP alone and in the presence of NK-1, NK-2, and both receptor antagonists. Scratch assay, transwell assay, and tumor growth factor-beta 1 (TGF-β1) assay were performed on buffalo fetal fibroblast culture. The cotreatment of fibroblast cultures with SP alone during the 24 h caused the significant proliferation and migrations of cells in both horizontal and vertical directions. The SP in the presence of spantide II (NK-1 antagonist) failed to stimulate this migration. The treatment of cells with SP in the presence of NK-2 antagonist treatment also showed a significant reduction of migration of cells with respect to SP treatment alone. The SP in the presence of both NK-1 and NK-2 antagonists failed to stimulate the horizontal migration of cells and most of the ineffectiveness of SP was observed in this combination. The TGF-β1 levels were significantly higher in the supernatants of cells that were exposed to SP alone. All other treatments have significantly lower TGF-β1 levels than SP alone treatment. It is concluded that different actions on fibroblast cells by SP were mainly mediated through the NK-1 receptor.

Characterization of the Action of Tachykinin Signaling on Pulsatile LH Secretion in Male Mice.

The alternation of the stimulatory action of the tachykinin neurokinin B (NKB) and the inhibitory action of dynorphin within arcuate (ARH) Kiss1 neurons has been proposed as the mechanism behind the generation of gonadotropin-releasing hormone (GnRH) pulses through the pulsatile release of kisspeptin. However, we have recently documented that GnRH pulses still exist in gonadectomized mice in the absence of tachykinin signaling. Here, we document an increase in basal frequency and amplitude of luteinizing hormone (LH) pulses in intact male mice deficient in substance P, neurokinin A (NKA) signaling (Tac1KO), and NKB signaling (Tac2KO and Tacr3KO). Moreover, we offer evidence that a single bolus of the NKB receptor agonist senktide to gonad-intact wild-type males increases the basal release of LH without changing its frequency. Altogether, these data support the dispensable role of the individual tachykinin systems in the generation of LH pulses. Moreover, the increased activity of the GnRH pulse generator in intact KO male mice suggests the existence of compensation by additional mechanisms in the generation of kisspeptin/GnRH pulses.

Sexual Dimorphic Distribution of Hypothalamic Tachykinin1 Cells and Their Innervations to GnRH Neurons in the Zebrafish

Substance P (SP) and neurokinin A (NKA), encoded by TAC1/Tac1 gene are members of the tachykinin family, which exert their neuromodulatory roles in vertebrate reproduction. In mammals, SP and NKA have been shown to regulate gonadotropin-releasing hormone (GnRH) and luteinizing hormone (LH) secretion via kisspeptin neurons. On the other hand, the role of SP/NKA in the regulation of reproduction in non-mammalian vertebrates is not well known. In the present study, we first localized expression of tac1 mRNA in the brain of male and female zebrafish, Danio rerio. Next, using an antibody against zebrafish tachykinin1 (Tac1), we examined the neural association of SP/NKA neural processes with GnRH3 neurons, and with kisspeptin (kiss2) neurons, in the brains of male and female zebrafish. In situ hybridization showed an apparent male-dominant tac1 expression in the ventral telencephalic area, the anterior and posterior parts of the parvocellular preoptic nucleus, and the suprachiasmatic nucleus. On the other hand, there was female-dominant tac1 expression in the ventral periventricular hypothalamus. Confocal images of double-labeled zebrafish Tac1 and GnRH3 showed associations between Tac1-immunoreactive processes and GnRH3 neurons in the ventral telencephalic area. In contrast, there was no apparent proximity of Tac1 processes to kiss2 mRNA-expressing neurons in the hypothalamus. Lastly, to elucidate possible direct action of SP/NKA on GnRH3 or Kiss2 neurons, expression of SP/NKA receptor, tacr1a mRNA was examined in regions containing GnRH3 or Kiss2 neurons by in situ hybridization. Expression of tacr1a mRNA was seen in several brain regions including the olfactory bulb, preoptic area and hypothalamus, where GnRH3 and Kiss2 cells are present. These results suggest that unlike in mammals, Tac1 may be involved in male reproductive functions via direct action on GnRH3 neurons but independent of kisspeptin in the zebrafish.

The SP-TLR axis, which locally primes the nasal mucosa, is impeded in patients with allergic rhinitis.

BackgroundSubstance P (SP) and toll‐like receptors (TLRs) contribute to airway disease, particularly during viral infection. We recently demonstrated that SP can act as an initial response to viral stimuli in the upper airway by upregulating TLRs in the nasal epithelia (the SP‐TLR axis). Patients with allergic rhinitis (AR) suffer from prolonged airway infections. The aim of the present study was to examine if patients with AR exhibit a disturbance in the SP‐TLR axis.MethodHuman nasal biopsies and human nasal epithelial cells (HNEC) from healthy volunteers and patients with AR were cultured in the presence of SP. Epithelial expression of TLR4, neutral endopeptidase (NEP) and neurokinin 1 (NK1) were evaluated with flow cytometry and/or quantitative polymerase chain reaction after 30 min to 24 h. The effect of SP on nasal lipopolysaccharide‐induced interleukin‐8 (IL‐8) release was investigated.ResultsSP stimulation of tissue from healthy volunteers resulted in a transient increase of the TLR4 expression, whereas stimulation of AR patient‐derived material led to a delayed and prolonged upregulation of TLR4. NEP expression in HNEC was lower in AR than healthy controls whereas NK1 receptor expression was increased. SP pretreatment increased TLR4‐dependent IL‐8 expression in healthy controls, but not in AR.ConclusionsSP‐induced regulation of TLR4 in the human nasal mucosa is disturbed in AR. An altered SP‐mediated innate immune response may contribute to the dysfunctional and often prolonged responses to infection in AR.

Elinzanetant (NT-814), a Neurokinin 1,3 Receptor Antagonist, Reduces Estradiol and Progesterone in Healthy Women.

ContextThe ideal therapy for endometriosis (EM) and uterine fibroids (UFs) would suppress estrogenic drive to the endometrium and myometrium, while minimizing vasomotor symptoms and bone loss associated with current treatments. An integrated neurokinin-kisspeptin system involving substance P and neurokinin B acting at the neurokinin (NK) receptors 1 and 3, respectively, modulates reproductive hormone secretion and represents a therapeutic target.ObjectiveThis work aimed to assess the effects of the novel NK1,3 antagonist elinzanetant on reproductive hormone levels in healthy women.MethodsA randomized, single-blinded, placebo-controlled study was conducted in 33 women who attended for 2 consecutive menstrual cycles. In each cycle blood samples were taken on days 3 or 4, 9 or 10, 15 or 16, and 21 or 22 to measure serum reproductive hormones. In cycle 2, women were randomly assigned to receive once-daily oral elinzanetant 40, 80, 120 mg, or placebo (N = 8 or 9 per group).ResultsElinzanetant dose-dependently lowered serum luteinizing hormone, estradiol (120 mg median change across cycle: –141.4 pmol/L, P = .038), and luteal-phase progesterone (120 mg change from baseline on day 21 or 22: –19.400 nmol/L, P = .046). Elinzanetant 120 mg prolonged the cycle length by median of 7.0 days (P = .023). Elinzanetant reduced the proportion of women with a luteal-phase serum progesterone concentration greater than 30 nmol/L (a concentration consistent with ovulation) in a dose-related manner in cycle 2 (P = .002). Treatment did not produce vasomotor symptoms.ConclusionNK1,3 receptor antagonism with elinzanetant dose-dependently suppressed the reproductive axis in healthy women, with the 120-mg dose lowering estradiol to potentially ideal levels for UFs and EM. As such, elinzanetant may represent a novel therapy to manipulate reproductive hormone levels in women with hormone-driven disorders.

Chemotherapy Remote Care Monitoring Program: Integration of SMS Text Patient-Reported Outcomes in the Electronic Health Record and Pharmacist Intervention for Chemotherapy-Induced Nausea and Vomiting.

Chemotherapy-induced nausea and vomiting (CINV) is a common cause of unplanned healthcare utilization. The University of Michigan Rogel Cancer Center initiated the chemotherapy remote care monitoring program (CRCMP) to proactively identify patients experiencing CINV and intervene before the need for urgent evaluation. High-risk patients for CINV are identified by neurokinin-1 (NK-1) antagonist administration, enrolled in the CRCMP, and received a daily text message survey for 7 days after chemotherapy administration to report symptoms. Responses above a set threshold trigger a message to the team pharmacist for intervention. The primary outcome of 14-day unplanned healthcare use was evaluated before and after CRCMP implementation. In 8 months, 652 patients received an NK-1 antagonist (2,244 cycles) and 387 patients were enrolled in the CRCMP (59%). Text message response rate was 94%. Clinical pharmacists provided 248 interventions in 121 patient episodes meeting threshold criteria. Fourteen-day unplanned healthcare use was decreased in the CRCMP-enrolled NK-1 episodes (6.68% v 4.53%, P = .02). Admissions were numerically lower for those enrolling in CRCMP when only admissions for nausea were considered (0.63% v 0.35%, P = .33). The CRCMP allowed for real-time management of patient-reported CINV symptom burden based on patient-reported outcomes (PROs) and an electronic medical record-integrated SMS text questionnaire. Clinical pharmacists were key team members to manage patient symptoms. Enrollment in CRCMP significantly reduced overall unplanned healthcare utilization. Although these changes were numerically small, any reduction in unnecessary care utilizing PROs can contribute to high-value care for patients with cancer.

Functional evaluation of NK1 antagonism on cue reactivity in opiate dependence; An fMRI study

BackgroundOpiate addiction is a major health challenge with substantial societal cost. Though harm minimisation strategies have been effective, there is a growing need for new treatments for detoxification and relapse prevention. Preclinical research has found neurokinin 1 (NK1) receptors have prominent effects on opiate reward and reinforcement, and human studies have found NK1 antagonism led to reductions in craving and withdrawal. However, its effect on brain mechanisms in opiate addiction has not yet been examined. MethodsThis study aims to assess the impact of NK1 antagonist aprepitant on heroin cue-elicited changes in blood-oxygenation level dependent (BOLD) signal in opiate dependent individuals undergoing detoxification. Participants will attend two scanning sessions and receive a single dose of aprepitant (320 mg) and a placebo in a randomised, cross-over design. During functional magnetic resonance imaging participants will undergo two runs of a cue reactivity task, which consists of passive viewing of drug cues or neutral cues in a block design fashion. We hypothesise that NK1 antagonism will attenuate the BOLD response to drug cues in the caudate nucleus and amygdala. Regions of interest were selected based on NK1 receptor density and their role in cue reactivity and craving.