ABSTRACT
Peritoneal fibrosis (PF) is an irreversible complication of peritoneal dialysis (PD) that leads to loss of peritoneal membrane function. We investigated PD effluent and serum levels and the tissue expression of chemokine (C-C motif) ligand 8 (CCL8) in patients with PD. Additionally, we investigated their association with PF in a mouse model. Eighty-two end-stage renal disease (ESRD) patients with PD were examined. CCL8 levels were measured via enzyme-linked immunosorbent assays in PD effluents and serum and analyzed with peritoneal transport parameters. Human peritoneal mesothelial cells (hPMCs) were obtained from the PD effluents of 20 patients. Primary cultured hPMCs were treated with recombinant (r) transforming growth factor (TGF)-ß, and CCL8 expression was assessed via western blotting. As the duration of PD increased, the concentration of CCL8 in PD effluents significantly increased. Correlations between peritoneal transport parameters and dialysate CCL8 levels were observed. Western blotting analysis showed that CCL8 was upregulated via rTGF-ß treatment, accompanied by increases in markers of inflammation, fibrosis, senescence, and apoptosis in hPMCs after induction of fibrosis with rTGF-ß. Anti-CCL8 monoclonal antibody (mAb) treatment suppressed the rTGF-ß-induced increase in all analyzed markers. Immunohistochemical analysis revealed that CCL8 along with fibrosis- and inflammation-related markers were significantly increased in the PF mouse model. Functional blockade of CCL8 using a CCR8 inhibitor (R243) abrogated peritoneal inflammation and fibrosis in vivo. In conclusion, high CCL8 levels in PD effluents may be associated with an increased risk of PD failure, and the CCL8 pathway is associated with PF. CCL8 blockade can ameliorate peritoneal inflammation and fibrosis.
Subject(s)
Peritoneal Fibrosis , Peritonitis , Animals , Mice , Humans , Peritoneal Fibrosis/prevention & control , Chemokine CCL8 , Peritoneum , Chemokines , Ligands , Inflammation , Disease Models, AnimalABSTRACT
Transcriptome profiling of tubulointerstitial tissue in glomerulonephritis may reveal a potential tubulointerstitial injury-related biomarker. We profiled manually microdissected tubulointerstitial tissue from biopsy cores of 65 glomerulonephritis cases, including 43 patients with IgA nephropathy, 3 with diabetes mellitus nephropathy, 3 with focal segmental glomerulosclerosis, 3 with lupus nephritis, 4 with membranous nephropathy and 9 with minimal change disease, and additional 22 nephrectomy controls by RNA sequencing. A potential biomarker was selected based on the false discovery rate, and experiments were performed in TNF-α-stimulated primary cultured human tubular epithelial cells (hTECs). We identified 3037 genes with low expression and 2852 genes with high expression in the disease samples compared to the controls. Dual-specificity phosphatase 1 (DUSP1) exhibited universal low expression in various diseases (log2 fold change, -3.87), with the lowest false discovery rate (7.03E-132). In further experimental validation study, DUSP1 overexpression ameliorated inflammatory markers related to MAP kinase pathways in hTECs, while pharmacologic inhibition of DUSP1 increased these markers. The combination of DUSP1 overexpression with low-concentration corticosteroid treatment resulted in more potent suppression of inflammation than high-concentration corticosteroid treatment alone. The profiled transcriptomes provide insights into the pathophysiology of tubulointerstitial injury in kidney diseases and may reveal a potential therapeutic biomarker.
Subject(s)
Glomerulonephritis, IGA , Glomerulonephritis , Biomarkers , Biopsy , Glomerulonephritis/drug therapy , Glomerulonephritis/genetics , Glomerulonephritis, IGA/drug therapy , Glomerulonephritis, IGA/genetics , Glomerulonephritis, IGA/metabolism , Humans , Phosphoric Monoester Hydrolases , RNA-SeqABSTRACT
Identification of a urinary metabolite biomarker with diagnostic or prognostic significance for early immunoglobulin A nephropathy (IgAN) is needed. We performed nuclear magnetic resonance-based metabolomic profiling and identified 26 metabolites in urine samples. We collected urine samples from 201, 77, 47, 36 and 136 patients with IgAN, patients with membranous nephropathy, patients with minimal change disease, patients with lupus nephritis and healthy controls, respectively. We determined whether a metabolite level is associated with the prognosis of IgAN through Cox regression and continuous net reclassification improvement (cNRI). Finally, in vitro experiments with human kidney tubular epithelial cells (hTECs) were performed for experimental validation. As the results, the urinary glycine level was higher in the IgAN group than the control groups. A higher urinary glycine level was associated with lower risk of eGFR 30% decline in IgAN patients. The addition of glycine to a predictive model including clinicopathologic information significantly improved the predictive power for the prognosis of IgAN [cNRI 0.72 (0.28-0.82)]. In hTECs, the addition of glycine ameliorated inflammatory signals induced by tumour necrosis factor-α. Our study demonstrates that urinary glycine may have diagnostic and prognostic value for IgAN and indicates that urinary glycine is a protective biomarker for IgAN.
Subject(s)
Biomarkers/metabolism , Glomerulonephritis, IGA/pathology , Glycine/urine , Metabolome , Adult , Case-Control Studies , Female , Glomerular Filtration Rate , Glomerulonephritis, IGA/metabolism , Humans , Male , Middle Aged , PrognosisABSTRACT
We have attempted to reduce blood use during the perioperative period to avoid complications associated with blood transfusions in pediatric patients undergoing open-heart surgery. We retrospectively reviewed clinical data of patients who underwent open-heart surgery (age < 15 years, body weight ≤ 30 kg) from January 2012 to October 2013. Our strategy to reduce transfusion volume included: (1) shortening the length of cardiopulmonary bypass (CPB) circuit, and adding red blood cells (RBC) to CPB circuit priming solution when preoperative hematocrit was ≤30%; (2) routine modified ultrafiltration in all patients; and (3) restricting RBC transfusions during postoperative period, given when hematocrit was ≤25%. In total, 349 cases were enrolled. The median age of patients was 7 months (1 day-168 months), and body weight was 7 kg (2.3-30 kg). We did not use blood products in 81 (23.2%) cases and did not add RBCs to CPB priming solution in 119 (34.1%) cases. Patients who did not require a transfusion showed a shorter intensive care unit (ICU) stays (0.97 ± 0.5 days) than patients who required a transfusion (4.1 ± 5.5 days, p = 0.003). Larger volume transfusion correlated with longer intubation durations, ICU and hospital stays, higher peak C-reactive protein levels, and an increased blood urea nitrogen/creatinine ratio. No significant problems were observed in patients with relatively lower hematocrit levels. Our strategy to reduce transfusion volume resulted in shorter ventilator support, ICU stay, hospitalization, reduced inflammatory reaction, and less kidney insult during the postoperative course in pediatric patients.
Subject(s)
Blood Transfusion/statistics & numerical data , Cardiac Surgical Procedures/methods , Cardiopulmonary Bypass/methods , Adolescent , Blood Transfusion/methods , Child , Child, Preschool , Critical Care , Humans , Infant , Infant, Newborn , Length of Stay , Perioperative Period , Retrospective Studies , Transfusion ReactionABSTRACT
Scytosiphon lomentaria (SL) is a brown seaweed with antioxidant and anti-inflammatory properties; however, its effects on obesity are unknown. In this research, we investigated the anti-obesity properties and underlying mechanisms of the SL extract in vitro and in vivo. In 3T3-L1 preadipocytes, SL extract inhibited lipid accumulation, decreased the expression of Acc1, C/ebpa, Pparg mRNA and p-ACC1, and increased the expression of Ucp1 mRNA, UCP1 and p-AMPK. In animal experiments, mice were fed a chow diet, a high-fat diet (HF; 60% of calories as fat), and high-fat diet with SL extract (150 and 300 mg/kg body weight) for eight weeks (n = 10/group). SL extract reduced HF-induced weight gain, epididymal fat weight, fat cell size, LDL-C, leptin, fasting glucose, and glucose tolerance. In addition, SL extract had comparable effects on mRNA expression in WAT and liver to those observed in vitro, thereby inhibiting p-ACC1/ACC1 and increasing p-AMPK/AMPK and UCP1 expression. Furthermore, SL extract decreased HF-induced Firmicutes/Bacteroidetes ratio and reversed HF-reduced Bacteroides spp., Bacteroides vulgatus, and Faecalibacterium prausnitzii. These findings suggest that SL extract can aid in weight loss in mice fed a high-fat diet by altering adipogenic and thermogenic pathways, as well as gut microbiota composition.
Subject(s)
Biological Products , Diet, High-Fat , Gastrointestinal Microbiome , Obesity , Animals , Mice , AMP-Activated Protein Kinases , Glucose , Mice, Inbred C57BL , Obesity/metabolism , RNA, Messenger/metabolism , Seaweed/chemistry , Biological Products/pharmacology , Phaeophyceae/chemistryABSTRACT
The present study examined the underlying mechanisms of mechanical allodynia and thermal hyperalgesia induced by the intracisternal injection of angiotensin (Ang) II. Intracisternal Ang II injection decreased the air puff threshold and head withdrawal latency. To determine the operative receptors for each distinct type of pain behavior, we intracisternally injected Ang II receptor antagonists 2 h after Ang II injection. Losartan, an Ang II type 1 receptor (AT1R) antagonist, alleviated mechanical allodynia. Conversely, PD123319, an Ang II type 1 receptor (AT2R) antagonist, blocked only thermal hyperalgesia. Immunofluorescence analyses revealed the co-localization of AT1R with the astrocyte marker GFAP in the trigeminal subnucleus caudalis and co-localization of AT2R with CGRP-positive neurons in the trigeminal ganglion. Intracisternal pretreatment with minocycline, a microglial inhibitor, did not affect Ang II-induced mechanical allodynia, whereas L-α-aminoadipate, an astrocyte inhibitor, significantly inhibited Ang II-induced mechanical allodynia. Furthermore, subcutaneous pretreatment with botulinum toxin type A significantly alleviated Ang II-induced thermal hyperalgesia, but not Ang II-induced mechanical allodynia. These results indicate that central Ang II-induced nociception is differentially regulated by AT1R and AT2R. Thus, distinct therapeutic targets must be regulated to overcome pain symptoms caused by multiple underlying mechanisms.
ABSTRACT
Ionizing radiation has become an inevitable health concern emanating from natural sources like space travel and from artificial sources like medical therapies. In general, exposure to ionizing radiation such as γ-rays is one of the methods currently used to stress specific model systems. In this study, we elucidated the long-term effect of acute and fractionated irradiation on DCX-positive cells in hippocampal neurogenesis. Groups of two-month-old C57BL/6 female mice were exposed to whole-body irradiation at acute dose (5 Gy) or fractional doses (1 Gy × 5 times and 0.5 Gy × 10 times). Six months after exposure to γ-irradiation, the hippocampus was analyzed. Doublecortin (DCX) immunohistochemistry was used to measure changes of neurogenesis in the subgranular zone (SGZ) of the hippocampal dentate gyrus (DG). The number of DCX-positive cells was significantly decreased in all acute and fractionally irradiation groups. The long-term changes in DCX-positive cells triggered by radiation exposure showed a very different pattern to the short-term changes which tended to return to the control level in previous studies. Furthermore, the number of DCX-positive cells was relatively lower in the acute irradiation group than the fractional irradiation groups (approximately 3.6-fold), suggesting the biological change on hippocampal neurogenesis was more susceptible to being damaged by acute than fractional irradiation. These results suggest that the exposure to γ-irradiation as a long-term effect can trigger biological responses resulting in the inhibition of hippocampal neurogenesis.
Subject(s)
Dentate Gyrus/radiation effects , Gamma Rays , Neurogenesis/radiation effects , Animals , Dentate Gyrus/cytology , Dentate Gyrus/metabolism , Dose-Response Relationship, Radiation , Doublecortin Domain Proteins , Doublecortin Protein , Female , Mice , Mice, Inbred C57BL , Microtubule-Associated Proteins/metabolism , Neuropeptides/metabolism , Whole-Body IrradiationABSTRACT
Obesity is a global health problem. It is also known to be a risk factor for the development of metabolic disorders, type 2 diabetes, systemic hypertension, cardiovascular disease, dyslipidemia, and atherosclerosis. In this study, we elucidated that Buddleja officinalis Maximowicz extract significantly inhibited lipid accumulation during 3T3-L1 adipocyte differentiation. Furthermore, Buddleja officinalis Maximowicz extract reduced the body weight gain induced through feeding a high-fat diet to C57BL/6 mice. The treatment of Buddleja officinalis Maximowicz extract significantly reduced the adipose tissue weight to 2.7/100 g of body weight in high-fat mice. When their adipose tissue morphology was investigated for histochemical staining, the distribution of cell size in the high-fat diet groups was hypertrophied compared with those from Buddleja officinalis Maximowicz extract-treated mice. In addition, in Buddleja officinalis Maximowicz extract-treated mice, a significant reduction of serum triglyceride and T-cholesterol was observed at to 21% and 17%, respectively. The discovery of bioactive compounds from diet or dietary supplementation is one of possible ways to control obesity and to prevent or reduce the risks of various obesity-related diseases. These results support that Buddleja officinalis Maximowicz extract is expected to create the therapeutic interest with respect to the treatment of obesity.
Subject(s)
Adipocytes/drug effects , Anti-Obesity Agents/administration & dosage , Buddleja , Obesity/drug therapy , Plant Extracts , 3T3-L1 Cells , Animals , Body Weight/drug effects , Buddleja/chemistry , Cell Differentiation/drug effects , Diet, High-Fat , Lipid Metabolism/drug effects , Mice , Mice, Inbred C57BL , Plant Extracts/administration & dosage , Plant Extracts/chemistry , Triglycerides/blood , Weight Gain/drug effectsABSTRACT
Objective: In this study, the sleep time and efficiency of recipients of hematopoietic stem cell transplantation (HSCT) were investigated throughout treatment and compared objective measurements with subjective self-reported data. Methods: Sleep time and efficiency were measured using both objective and subjective methods throughout the treatment period in inpatients receiving HSCT. The participants were recruited among HSCT inpatients at a tertiary hospital in Seoul, South Korea, between August 2019 and August 2020. Actigraphy was used to measure objective sleep time and efficiency. Subjective sleep time and quality were measured using the sleep diary and Insomnia Severity Index. Measurement data from 40 patients were analyzed. Repeated-measures analysis of variance was used to compare the differences between objective and subjective values in total sleep time and sleep efficiency. Results: The total sleep time was the lowest during the administration of anticancer drugs before stem cell transplantation. The total sleep time of patients with HSCT differed significantly over time when offsetting the difference in the measurement method. There were no significant differences between subjective and objective results for sleep time, and the interaction between the two methods over time was not significant. However, meaningful differences were found among the groups in sleep efficiency throughout the treatment period and between objective and subjective methods, as well as a statistically significant interaction between the two methods over time. Conclusions: Actigraphy misclassified patients' low-energy state with little movement due to immune system impairment during treatment as sleep, resulting in high measured sleep efficiency, whereas their self-reported sleep efficiency was very low. Therefore, subjective measures might be more accurate for measuring sleep efficiency in HSCT patients.
ABSTRACT
In this study, we elucidated the inhibitory effect of fucoidan from marine brown algae on the lipid accumulation in differentiated 3T3-L1 adipocytes and its mechanism. The treatment of fucoidan in a dose-dependent manner was examined on lipid inhibition in 3T3-L1 cells by using Oil Red O staining. Fucoidan showed high lipid inhibition activity at 200 µg/mL concentration (P < 0.001). Lipolytic activity in adipocytes is highly dependent on hormone sensitive lipase (HSL), which is one of the most important targets of lipolytic regulation. Here, we examined the biological response of fucoidan on the protein level of lipolysis pathway. The expressed protein levels of total hormone sensitive lipase (HSL) and its activated form, phosphorylated-HSL were significantly increased at concentration of 200 µg/mL fucoidan. Furthermore, insulin-induced 2-deoxy-D-[³H] glucose uptake was decreased up to 51% in fucoidan-treated cells as compared to control. Since increase of HSL and p-HSL expression and decrease of glucose uptake into adipocytes are known to lead to stimulation of lipolysis, our results suggest that fucoidan reduces lipid accumulation by stimulating lipolysis. Therefore, these results suggest that fucoidan can be useful for the prevention or treatment of obesity due to its stimulatory lipolysis.
Subject(s)
Lipid Metabolism/drug effects , Lipolysis/drug effects , Phaeophyceae/chemistry , Polysaccharides/pharmacology , 3T3-L1 Cells , Adipocytes/drug effects , Adipocytes/metabolism , Animals , Cell Differentiation/drug effects , Cell Line , Cell Survival/drug effects , Glucose/metabolism , Insulin/metabolism , Lipolysis/genetics , Mice , Obesity/metabolism , Polysaccharides/isolation & purification , Sterol Esterase/metabolismABSTRACT
This study aimed inhibition mechanisms of auditory processing in the group with autistic features. Thirty-two children (autistic group = 16, typically developing [TD] group = 16) received neuropsychological tests, IQ test and experimental tasks. Both groups showed similar performances except the processing speed index. The results showed that the group with autistic features had less inhibition of return (IOR) than the TD group. However, we did not get a statistically significant group difference in the auditory Go-NoGo task. These results might be attributed to a ceiling effect due to an adjustment failure of a difficulty level instead of showing that the group with autistic features would have intact inhibitory or pitch discriminative function problems. In conclusion, this study showed that the group with autistic features could have an inhibitory processing difficulty in both auditory and visual IOR tasks even when their general cognitive functions are relatively intact. This study presented a possibility that the group with autistic features might have a basic inhibitory function problem, but these findings should be investigated in the further study with enough samples. In addition, we are going to revise the auditory Go-NoGo task and verify the feasibility as a tool to detect ASD in an early stage in the following study.
Subject(s)
Auditory Perception/physiology , Autism Spectrum Disorder/physiopathology , Inhibition, Psychological , Child , Female , Humans , Intelligence Tests , Male , Neuropsychological Tests , Problem BehaviorABSTRACT
Despite the increasing prevalence of overweight or obesity in the global population, most of the approved drugs for obesity are still not ideal for long-term use due to severe cardiovascular and/or neurological side effects. Therefore, we designed a library-implemented virtual screening (VS) approach to discover new anti-obesity agents without significant toxicity. The Bayesian classification and 3D pharmacophore model for the VS process were built by using the screening results of our in-house library of natural piper amide-like compounds, which possess a wide range of biological activities and relatively low toxicities. The VS process identified six compounds of different classes with enhanced inhibitory activities against lipid accumulation and without toxicity. Moreover, the most active compound with an oxadiazole scaffold resulted in weight loss and improved the fatty liver condition of mice with overnutrition in animal experiments.
ABSTRACT
INTRODUCTION: This study compared the stemness and differentiation potential of stem cells derived from the apical complex (apical complex cells [ACCs]) and coronal pulp (dental pulp stem cells [DPSCs]) of human immature permanent teeth with the aim of determining a more suitable source of stem cells for regeneration of the dentin-pulp complex. METHODS: ACC and DPSC cultures were established from 13 human immature permanent teeth using the outgrowth method. The proliferation capacity and colony-forming ability of ACCs and DPSCs were evaluated. ACCs and DPSCs were analyzed for mesenchymal stem cell markers using flow cytometry. The adipogenic and osteogenic differentiation potential of ACCs and DPSCs were evaluated using the quantitative real-time polymerase chain reaction and histochemical staining. ACCs and DPSCs were transplanted subcutaneously in immunocompromised mice using macroporous biphasic calcium phosphate as a carrier. The histomorphologic characteristics of the newly formed tissues were verified using hematoxylin-eosin staining and immunohistochemical staining. Quantitative alkaline phosphatase analysis and quantitative real-time polymerase chain reaction using BSP, DSPP, POSTN, and ColXII were performed. RESULTS: ACCs and DPSCs showed similar cell proliferation potential and colony-forming ability. The percentage of mesenchymal stem cell markers was similar between ACCs and DPSCs. In the in vitro study, ACCs and DPSCs showed adipogenic and osteogenic differentiation potential. In the in vivo study, ACCs and DPSCs formed amorphous hard tissue using macroporous biphasic calcium phosphate particles. The quantity and histomorphologic characteristics of the amorphous hard tissue were similar in the ACC and DPSC groups. Formation of periodontal ligament-like tissue, positive to Col XII, was observed in ACC transplants, which was absent in DPSC transplants. CONCLUSIONS: ACCs and DPSCs showed similar stemness, proliferation rate, and hard tissue-forming capacity. The notable difference was the periodontal ligament-like fiber-forming capacity of ACCs, which indicates the presence of various lineages of stem cells in the apical complex compared with the coronal pulp. Regarding regeneration of the dentin-pulp complex, the coronal pulp can be a suitable source of stem cells considering its homogenous lineages of cells and favorable osteo/odontogenic differentiation potential.
Subject(s)
Cell Differentiation , Dental Pulp , Osteogenesis , Stem Cells , Animals , Cell Adhesion Molecules , Cell Proliferation , Cells, Cultured , Dentin , Humans , Mice , Proteins/metabolism , RegenerationABSTRACT
The authors in this article explore the experiences of eight South Korean nurses during an outbreak of the Middle East Respiratory Syndrome (MERS), which took place in the fall of 2015. These nurses were mandated to remain in isolation in an intensive care unit (ICU) dedicated to the treatment of the patients with the MERS virus for 7 days. Parse's humanbecoming theory was used to frame the discussion. Three themes found in the nurse's stories are discussed: feeling hopeless and cut off, feeling shame and overworked, and feeling pride in fulfilling a duty. The nurses discuss how they overcame the difficulties of their situation, which ultimately reinforced their identities as nurses.
Subject(s)
Coronavirus Infections/nursing , Nurses/psychology , Patient Isolation/psychology , Adult , Disease Outbreaks , Female , Humans , Intensive Care Units/organization & administration , Republic of KoreaABSTRACT
BACKGROUND: Based on the fact that B-cell activating factor (BAFF) and a proliferation-inducing ligand (APRIL) have a regulatory role in B cell biology, excessive levels of these cytokines can promote autoimmune pathogenesis. However, the expression and implication remain unresolved in cases of membranous nephropathy (MN). RESULTS: The plasma BAFF levels of the primary MN patients were higher than those of healthy controls but lower than those of secondary MN patients, whereas the APRIL levels were similar between the MN patients and healthy controls. The BAFF levels were higher in relapse cases, whereas the APRIL levels were higher in the patients who did not experience remission compared with the counterpart patients. The ectopic expression of BAFF and APRIL was observed in the glomeruli or circulating B cells of MN patients, and this high expression trend was similar to that of lupus patients. CONCLUSIONS: Expression profile of BAFF and APRIL in MN is similar to that of other autoimmune disease, which affects the kidney outcomes. METHODS: Plasma BAFF and APRIL levels were measured upon kidney biopsy in patients with primary (n = 89) and secondary MN (n = 13), and the results were compared with the levels in healthy controls (n = 111). The kidney outcomes (e.g., remission and relapse) were traced for the median of 3 years. Aberrant expression of the cytokines was evaluated in the kidney and circulating B cells using immunohistochemistry and flow cytometry analyses, respectively.
ABSTRACT
BACKGROUND: This study examined the degree of hemolysis during vacuum-assisted venous drainage at different negative pressures to identify an adequate negative pressure that provides effective venous drainage without significant hemolysis in open-heart surgery in children weighing less than 10 kg. METHODS: Patients weighing less than 10 kg who underwent surgery for ventricular septal defect or atrial septal defect from 2011 to 2014 were enrolled. We used one of four negative pressures (20, 30, 40, or 60 mm Hg) for each patient. We measured haptoglobin, plasma hemoglobin, aspartate aminotransferase, and lactate dehydrogenase levels in the patients' blood three times perioperatively and determined the potential correlation between the change in each parameter with the level of negative pressure. RESULTS: Forty-six patients were enrolled in this study (mean age: 7.1 ± 7.0 months, mean body weight: 6.1 ± 1.8 kg). There were no significant differences according to the degree of negative pressure with respect to patient age, body weight, cardiopulmonary bypass (CPB) time, aorta cross-clamping time, blood flow during CPB, or lowest body temperature. All parameters that we measured reflected progression of hemolysis during CPB; however, the degree of change in the parameters did not correlate with negative pressure. CONCLUSION: In pediatric patients weighing less than 10 kg, the change in the degree of hemolysis did not differ with the amount of negative pressure. We may apply negative pressures up to 60 mm Hg without increasing the risk of hemolysis, with almost same the level of hemolysis using negative pressures of 20, 30, and 40 mm Hg for effective venous drainage and an ideal operative field during open-heart surgery.
Subject(s)
Body Weight , Cardiac Surgical Procedures/methods , Cardiopulmonary Bypass/methods , Drainage/methods , Heart Septal Defects, Atrial/surgery , Hemolysis , Child, Preschool , Female , Femoral Vein , Humans , Infant , Infant, Newborn , Male , Vacuum , Vena Cava, SuperiorABSTRACT
Mechanical allodynia is a common symptom found in neuropathic patients. Hyperpolarization-activated cyclic nucleotide-gated channels and their current, I(h), have been suggested to play an important role in neuropathic pain, especially in mechanical allodynia and spontaneous pain, by involvement in spontaneous ectopic discharges after peripheral nerve injury. Thus, I(h) blockers may hold therapeutic potential for the intervention of mechanical allodynia under diverse neuropathic conditions. Here we show that eugenol blocks I(h) and abolishes mechanical allodynia in the trigeminal system. Eugenol produced robust inhibition of I(h) with IC(50) of 157 µM in trigeminal ganglion (TG) neurons, which is lower than the dose of eugenol that inhibits voltage-gated Na channels. Eugenol-induced I(h) inhibition was not mediated by G(i/o)-protein activation, but was gradually diminished by an increase in intracellular cAMP concentration. Eugenol also inhibited I(h) from injured TG neurons which were identified by retrograde labeling with DiI and reversed mechanical allodynia in the orofacial area after chronic constriction injury of infraorbital nerve. We propose that eugenol could be potentially useful for reversing mechanical allodynia in neuropathic pain patients.