Transient receptor potential ankyrin 1 (TRPA1) and transient receptor potential melastatin 8 (TRPM8) in human odontoblast-like cells participate in lipopolysaccharide-induced immune response.

OBJECTIVES: To investigate whether transient receptor potential ankyrin 1 (TRPA1) and transient receptor potential melastatin 8 (TRPM8) have a function in responding to environmental stimuli in human odontoblast-like cells (hOLCs). Additionally, to explore whether activation of TRPA1 and TRPM8 in hOLCs participates in the regulation of the inflammatory process. DESIGN: Changes in gene and protein expression levels of TRPA1 and TRPM8 in cultured hOLCs following lipopolysaccharide (LPS) stimulation, which mimics inflammation, were examined using quantitative reverse transcription-polymerase chain reaction and western blot analysis. Furthermore, we compared the expression profiles of 80 cytokines between LPS- and vehicle-treated hOLCs and investigated how the production of highly increased cytokines in LPS-treated hOLCs was affected by the pharmacological inhibition of TRPA1 and TRPM8. RESULTS: The expression of TRPA1 and TRPM8 in hOLCs was observed and their mRNAs and proteins were upregulated in hOLCs after LPS treatment. Moreover, cytokine antibody assays revealed that monocyte chemoattractant protein-1 (MCP-1, CCL2), growth-regulated protein α (GROα, CXCL1), interleukin-6 (IL-6), and IL-8 (CXCL8) were significantly upregulated by LPS. The pharmacological inhibition of TRPA1 (HC-030031) during LPS treatment attenuated the expression of CCL2, CXCL1, and IL-8, whereas the pharmacological inhibition of TRPM8 (PF05105679) suppressed the expression of CCL2, CXCL1, and IL-8 as well as IL-6. CONCLUSIONS: These results indicate that hOLCs express TRPA1 and TRPM8, which are upregulated during inflammation. In addition to being sensors of potentially harmful stimuli, TRPA1 and TRPM8 in hOLCs play important roles in regulating inflammatory responses.

A case report of two pelviscopic resections of fibrothecomas originating from the left ovary with recurrence after ten years.

RATIONALE: Fibrothecomas are benign ovarians tumors. These are solid sex-cord-stromal tumors, accounting for 1% to 4.7% of all ovarian neoplasms. Their recurrence rate is known to be only 2% following ovarian sparing local mass excision. We report an uncommon case of 2 pelviscopic resections of fibrothecomas originating from the left ovary with recurrence after 10 years in a 34-year-old woman. PATIENT CONCERNS: A 34-year-old married woman was diagnosed with 41 mm sized left ovarian recurrent fibrothecoma. We performed mass excision pelviscopically the first time 10 years ago. She gave birth to her second baby at 7 years after the first surgery. Ten years after the first surgery, fibrothecoma recurred on the same ovary with size larger than before. DIAGNOSES: At the time of its first occurrence 10 years ago, the ultrasound scan revealed a 34 × 23 mm-sized solid hypoechoic mass with well-demarcated margins and minimal Doppler flows. Ultrasound findings at the time of recurrence 10 years later showed the same findings, with its size increased to 41 × 40 mm. Final pathologic findings showed left ovarian fibrothecoma. INTERVENTIONS: After her admission to the hospital, we performed pelviscopic removal of left ovarian fibroma. Microscopic examination revealed predominantly bland spindle cells with collagenous stroma, showing fascicular and storiform growth. OUTCOMES: Surgeries were successful. The patient had been followed-up regularly for 3 years after last surgery. She did not experience any complications. She remained disease-free. LESSONS: Repetitive local mass excision appears to be an effective surgical option in women of reproductive age. Although there is a sufficient possibility of recurrence several years to decades after only mass excision, mass excision is more appropriate than total oophorectomy in women of childbearing age. Pelviscopic surgery is recommended.

Synaptic connectivity of the TRPV1-positive trigeminal afferents in the rat lateral parabrachial nucleus.

Recent studies have shown a direct projection of nociceptive trigeminal afferents into the lateral parabrachial nucleus (LPBN). Information about the synaptic connectivity of these afferents may help understand how orofacial nociception is processed in the LPBN, which is known to be involved primarily in the affective aspect of pain. To address this issue, we investigated the synapses of the transient receptor potential vanilloid 1-positive (TRPV1+) trigeminal afferent terminals in the LPBN by immunostaining and serial section electron microscopy. TRPV1 + afferents arising from the ascending trigeminal tract issued axons and terminals (boutons) in the LPBN. TRPV1+ boutons formed synapses of asymmetric type with dendritic shafts and spines. Almost all (98.3%) TRPV1+ boutons formed synapses with one (82.6%) or two postsynaptic dendrites, suggesting that, at a single bouton level, the orofacial nociceptive information is predominantly transmitted to a single postsynaptic neuron with a small degree of synaptic divergence. A small fraction (14.9%) of the TRPV1+ boutons formed synapses with dendritic spines. None of the TRPV1+ boutons were involved in axoaxonic synapses. Conversely, in the trigeminal caudal nucleus (Vc), TRPV1+ boutons often formed synapses with multiple postsynaptic dendrites and were involved in axoaxonic synapses. Number of dendritic spine and total number of postsynaptic dendrites per TRPV1+ bouton were significantly fewer in the LPBN than Vc. Thus, the synaptic connectivity of the TRPV1+ boutons in the LPBN differed significantly from that in the Vc, suggesting that the TRPV1-mediated orofacial nociception is relayed to the LPBN in a distinctively different manner than in the Vc.

Increase of glutamate in satellite glial cells of the trigeminal ganglion in a rat model of craniofacial neuropathic pain.

Introduction: Satellite glial cells (SGCs) that envelop the cell bodies of neurons in sensory ganglia have been shown to both release glutamate, and be activated by glutamate in the context of nociceptive signaling. However, little is known about the subpopulations of SGCs that are activated following nerve injury and whether glutamate mechanisms in the SGCs are involved in the pathologic pain. Methods: To address this issue, we used light and electron microscopic immunohistochemistry to examine the change in the glutamate levels in the SGCs and the structural relationship between neighboring neurons in the trigeminal ganglion (TG) in a rat model of craniofacial neuropathic pain, CCI-ION. Results: Administration of ionomycin, ATP and Bz-ATP induced an increase of extracellular glutamate concentration in cultured trigeminal SGCs, indicating a release of glutamate from SGCs. The level of glutamate immunostaining in the SGCs that envelop neurons of all sizes in the TG was significantly higher in rats with CCI-ION than in control rats, suggesting that SGCs enveloping nociceptive as well as non-nociceptive mechanosensitive neurons are activated following nerve injury, and that the glutamate release from SGCs increases in pathologic pain state. Close appositions between substance-P (SP)-immunopositive (+) or calcitonin gene-related peptide (CGRP)+, likely nociceptive neurons, between Piezo1+, likely non-nociceptive, mechanosensitive neurons and SP+ or CGRP+ neurons, and between SGCs of neighboring neurons were frequently observed. Discussion: These findings suggest that glutamate in the trigeminal SGCs that envelop all types of neurons may play a role in the mechanisms of neuropathic pain, possibly via paracrine signaling.

A case report of pelviscopic resection of lipoleiomyoma originating from the uterine cervix in a postmenopausal woman.

RATIONALE: Lipoleiomyoma is a rare neoplasm of the uterus. It is considered a variant of uterine myomas. Its reported incidence varies from 0.03% to 0.2%. Lipoleiomyoma consists of variable proportions of mature lipocytes and smooth muscle cells. These tumors generally occur in asymptomatic obese perimenopausal or postmenopausal women. About 90.7% of lipoleiomyomas arise from the uterine corpus, with only 6.5% arising from the cervix. When it occurs in the cervix, it is difficult to diagnose and treat it. We report an uncommon case of pelviscopic resection of uterine cervical lipoleiomyoma showing continuous growth after menopause. PATIENT CONCERNS: A 55-year-old postmenopausal woman was diagnosed with 40 mm-sized uterine myoma 4 years ago. The size of the mass increased to 58 mm in the last year. DIAGNOSES: An ultrasound scan revealed a 58 × 34-mm-sized round hyperechogenic and barely vascularity mass that appeared to have originated on the left side of the uterine cervix. Final pathologic findings showed lipoleiomyoma. INTERVENTIONS: After admission to the hospital, we performed pelviscopic removal of uterine lipoleiomyoma and both tubes. Microscopic examination revealed a significant amount of fat cells between muscle cells. OUTCOMES: Surgeries were successful. The patient had been followed up regularly for three years after surgery. She did not experience any complications. She remained disease-free. LESSONS: Although lipoleiomyomas mainly occur in postmenopausal women, they can also occur in the uterine cervix. They can increase in size after menopause. They can be removed laparoscopically. If a hyperechoic mass occurred in the uterus after menopause that keeps growing without symptoms, a differential diagnosis of lipoleiomyomas must be performed.

Expression of Piezo1 in the Trigeminal Neurons and in the Axons That Innervate the Dental Pulp.

Information on the neurons and axons that express the mechanosensitive channel Piezo1 and its expression in axons innervating the dental pulp may help understand the nature of the Piezo1-mediated mechanosensation and the underlying mechanism of dentin sensitivity elicited by mechanical stimuli. For this, we here investigated the neurochemical properties of the neurons in the rat trigeminal ganglion (TG) and their axons in its sensory root that express Piezo1 and the expression of Piezo1 in the rat and human dental pulp by light and electron microscopic immunohistochemistry and quantitative analysis. Piezo1 was expressed mainly in medium-sized and large TG neurons. Piezo1-immunopositive (+) neurons frequently coexpressed the marker for neurons with myelinated axons, NF200, but rarely the markers for neurons with unmyelinated axons, CGRP or IB4. In the sensory root of TG, Piezo1 was expressed primarily in small myelinated axons (Aδ, 60.2%) but also in large myelinated (Aß, 24.3%) and unmyelinated (C, 15.5%) axons. In the human dental pulp, Piezo1 was expressed in numerous NF200+ axons, which formed a network in the peripheral pulp and often "ascended" toward the dentin. Most Piezo1+ myelinated axons in the radicular pulp became unmyelinated in the peripheral pulp, where Piezo1 immunoreaction product was associated with the axonal plasma membrane, suggesting a functional role of Piezo1 in the peripheral pulp. These findings suggest that Piezo1 is involved primarily in mediating the acute pain elicited by high-threshold mechanical stimuli, and that the Piezo1-mediated dental mechanotransduction occurs primarily in the axons in the peripheral pulp.

Ultrastructure of Rat Rostral Nucleus of the Solitary Tract Terminals in the Parabrachial Nucleus and Medullary Reticular Formation.

Neurons in the rostral nucleus of the solitary tract (rNST) receive taste information from the tongue and relay it mainly to the parabrachial nucleus (PBN) and the medullary reticular formation (RF) through two functionally different neural circuits. To help understand how the information from the rNST neurons is transmitted within these brainstem relay nuclei in the taste pathway, we examined the terminals of the rNST neurons in the PBN and RF by use of anterograde horseradish peroxidase (HRP) labeling, postembedding immunogold staining for glutamate, serial section electron microscopy, and quantitative analysis. Most of the anterogradely labeled, glutamate-immunopositive axon terminals made a synaptic contact with only a single postsynaptic element in PBN and RF, suggesting that the sensory information from rNST neurons, at the individual terminal level, is not passed to multiple target cells. Labeled terminals were usually presynaptic to distal dendritic shafts in both target nuclei. However, the frequency of labeled terminals that contacted dendritic spines was significantly higher in the PBN than in the RF, and the frequency of labeled terminals that contacted somata or proximal dendrites was significantly higher in the RF than in the PBN. Labeled terminals receiving axoaxonic synapses, which are a morphological substrate for presynaptic modulation frequently found in primary sensory afferents, were not observed. These findings suggest that the sensory information from rNST neurons is processed in a relatively simple manner in both PBN and RF, but in a distinctly different manner in the PBN as opposed to the RF.

Characteristics of Vaginal Microbiome in Women with Pelvic Inflammatory Disease in Korea.

Human vaginal microorganisms play an important role in maintaining good health throughout the human life cycle. An imbalance in the vaginal microbiota is associated with an increased risk of pelvic inflammatory disease (PID). This study aimed to characterize and compare vaginal microbial profiles of premenopausal Korean women with and without PID. 74 Korean premenopausal female vaginal samples were obtained; 33 were from healthy women (a control group) and 41 from PID patients. Vaginal fluid samples were collected from the vaginal wall and posterior cervix and then analyzed by 16S ribosomal ribonucleic acid (rRNA) gene-based amplicon sequencing. Results showed a significant difference between the vaginal microbial communities of the two groups (Jensen-Shannon, p = 0.014; Bray-Curtis, p = 0.009; Generalized UniFrac, p = 0.007; UniFrac, p = 0.008). Lactobacillus accounted for the highest percentage (61.0%) of the control group but was significantly decreased (34.9%) in PID patients; this was the most significant difference among all bacterial communities (p = 0.028, LDA effect size = 5.129). In addition, in the PID patient group, species diversity significantly increased (Simpson, p = 0.07) as the proportion of various pathogens increased evenly, resulting in a polymicrobial infection. Similarly, lactate, which constituted the highest percentage of the organic acids in the control group, was significantly decreased in the PID patient group (p = 0.04). The present study's findings will help understand PID from the microbiome perspective and are expected to contribute to the development of more efficient PID diagnosis and treatment modalities.

Changes in the Microbiome of Vaginal Fluid after Menopause in Korean Women.

Various microorganisms reside in the human vagina; the vaginal microbiome is closely linked to both vaginal and general health, and for this reason, microbiome studies of the vagina are an area of research. In this study, we analyzed the vaginal microbiome of women before and after menopause to further increase our understanding of the vaginal microbiome and its contribution to general health. We did a 16s rRNA gene-based metagenomic analysis on the vaginal fluids of 11 premenopausal and 19 postmenopausal women in Korea. We confirmed that the taxonomic composition was significantly different between the two groups. In postmenopausal women, species richness was significantly decreased, but species diversity was significantly increased. In particular, among the taxonomic components corresponding to all taxon ranks of the vaginal microbiome, a reduction in Lactobacillus taxa after menopause contributed the most to the difference between the two groups. In addition, we confirmed through metabolic analysis that the lactic-acid concentration was also decreased in the vaginal fluid of women after menopause. Our findings on the correlation between menopause and the microbiome could help diagnose menopause and enhance the prevention and treatment diseases related to menopause.

Safety and Effectiveness of Dienogest (Visanne®) for Treatment of Endometriosis: A Large Prospective Cohort Study.

Dienogest (DNG) is a progestin with highly selective progesterone activity and known to be effective in the treatment of endometriosis. This prospective cohort study in patients who had been treated with DNG 2 mg (Visanne®) for endometriosis was conducted to assess the safety and effectiveness of DNG in a large Korean cohort. This study included 3356 patients with endometriosis from 73 centers in Korea. All patients were treated with DNG 2 mg daily and were followed up for at least 6 months after initial visit. Any adverse events were recorded including severity, onset/closing date, outcomes, treatments, and the causality with DNG. Effectiveness of DNG was measured by changes in visual analogue scale (VAS) from baseline at the end of follow-up. The mean age of the subjects was 34.96 years, and the mean duration of treatment was 285.44 days. Incidence of adverse drug reaction (ADR) was 13.27% (413/3113). The most frequently reported ADR were "abnormal uterine bleeding" 4.14% (129/3113), "increased weight" 2.57% (80/3113), and "headache" 1.22% (38/3113). The number of patients (%) with favorable bleeding patterns was observed to increase as the duration of treatment increases. Amenorrhea was observed in 29.63%, 41.25%, 46.26%, and 53.20% of patients at 3 months, 6 months, 12 months, and more than 12 months follow-up period, respectively. The mean (±SD) VAS change from baseline at the last follow-up visit was -28.19 ± 28.39 mm (P value < 0.0001). This large cohort study confirms, in routine clinical practice, that DNG is safe and effective for treatment of endometriosis.

A case report of pelviscopic resection of invasive hydatidiform mole.

RATIONALE: Invasive moles occur in the fertile period, with about 95% occurring after previous mole removal and the remaining 5% occurring after several other pregnancies. PATIENT CONCERNS: A 27-year-old patient developed a rare invasive mole two months after a missed abortion. DIAGNOSES: A transvaginal ultrasound scan revealed a 3.6 × 2.9 × 2.4 cm sized lesion with cystic vascular areas within it, within the myometrium of the right fundal posterior region of the uterus. There was no metastasis to other organs. INTERVENTIONS: After administration of methotrexate, the level of beta-human chorionic gonadotropin (ß-hCG) was elevated and liver enzymes were also markedly elevated. She wanted to retain fertility for future pregnancies. After laparoscopic removal of the myometrial invasive mole, the incision site was sutured with a 3-0 V-Loc. OUTCOMES: One year later, a natural pregnancy occurred and a cesarean section was performed at 36 weeks. LESSONS: This is the first reported case of its type. Our case demonstrated that pelviscopic removal of an invasive mole is possible if there are no other metastases, and that future pregnancy and childbirth are still feasible in women of reproductive age.

Predictive value of serum uric acid levels for adverse perinatal outcomes in preeclampsia.

Preeclampsia is a multisystem disorder associated with pregnancy and is a common cause of perinatal morbidity. The aim of this study was to determine whether elevated serum uric acid levels, alone or in combination with other laboratory factors could predict preeclampsia in women with adverse perinatal outcomes.We conducted a prospective observational study of women who were admitted to Soonchunhyang University Cheonan Hospital from January 2016 to December 2016. Demographic, clinical and laboratory data were collected for each pregnancy at the time of delivery. Women were grouped according to status (preeclampsia or normotensive), and a logistic regression analysis was used to determine the relationship between serum uric acid levels and adverse outcomes.The mean age of the study participants was 31.3 ±â€Š5.0 years. In patients with preeclampsia, serum uric acid level was associated with the severity of preeclampsia, including blood pressure (R = 0.321, P = .014), serum creatinine levels (R = 0.505, P < .001), and proteinuria (P = .014), as well as adverse fetal outcomes, including preterm labor (P = .027) and low birth weight delivery (P = .001). The optimal maternal serum uric acid threshold that predicted low birth weight at delivery was 6.35 mg/dL (sensitivity, 0.58; specificity, 0.95). The multivariable logistic regression model that was used to predict low birth weight at delivery displayed an area under the receiver-operating characteristic curve of 0.902 (95% confidence interval, 0.817-0.986).In women with preeclampsia, maternal serum uric acid level is an important parameter for predicting low birth weight. Additionally, the combination of uric acid, hemoglobin, and bilirubin levels appear to be optimal for predicting low birth weight in women with preeclampsia.

Positive culture rate and antimicrobial susceptibilities of Mycoplasma hominis and Ureaplasma urealyticum.

OBJECTIVE: To assess positive culture rate and antimicrobial susceptibilities of Mycoplasma hominis (MH) and Ureaplasma urealyticum (UU) in symptomatic general population and pregnant women admitted with preterm labor and premature rupture of membranes. METHODS: We retrospectively reviewed medical records of patients who have undergone culture test and antimicrobial susceptibilities at our center from January 2017 to April 2018. Patients with positive culture for MH, UU, or both were included in this study. RESULTS: There were 200 patients who were eligible for enrollment. Of these patients, 34 (17%) were pregnant women and 166 (83%) were non-pregnant women. Of these 200 patients, positive culture results were as follows: MH only, n=10 (5%); UU only, n=58 (29%); and both MH and UU, n=36 (18%). Susceptibilities of MH only to doxycycline, erythromycin, ciprofloxacin, and azithromycin were 100%, 10%, 40%, and 0%, respectively. Susceptibilities of UU only to doxycycline, erythromycin, ciprofloxacin, and azithromycin were 94.8%, 87.9%, 5.2%, and 81%, respectively. Susceptibilities of both MH and UU to doxycycline, erythromycin, ciprofloxacin, and azithromycin were 97.2%, 5.6%, 11.1%, and 11.1%, respectively. CONCLUSION: UU only was the leading causative pathogen for genitourinary infection in our study. MH only accounted for about one sixth of UU only infections. Doxycycline was still the best antibiotics as most patients with MH only, UU only, or both MH and UU positive culture showed susceptibility. For ciprofloxacin, less than 12% of those with UU only and both MH and UU culture positive results showed susceptibility.

Natural Killer Cells Degenerate Intact Sensory Afferents following Nerve Injury.

Sensory axons degenerate following separation from their cell body, but partial injury to peripheral nerves may leave the integrity of damaged axons preserved. We show that an endogenous ligand for the natural killer (NK) cell receptor NKG2D, Retinoic Acid Early 1 (RAE1), is re-expressed in adult dorsal root ganglion neurons following peripheral nerve injury, triggering selective degeneration of injured axons. Infiltration of cytotoxic NK cells into the sciatic nerve by extravasation occurs within 3 days following crush injury. Using a combination of genetic cell ablation and cytokine-antibody complex stimulation, we show that NK cell function correlates with loss of sensation due to degeneration of injured afferents and reduced incidence of post-injury hypersensitivity. This neuro-immune mechanism of selective NK cell-mediated degeneration of damaged but intact sensory axons complements Wallerian degeneration and suggests the therapeutic potential of modulating NK cell function to resolve painful neuropathy through the clearance of partially damaged nerves.

The full-length mitochondrial genome of the Fernholm's hagfish, Myxine fernholmi (Myxini; Myxiniformes; Myxinidae).

The full-length mitochondrial genome of the Fernholm's hagfish, Myxine fernholmi (Myxini; Myxiniformes; Myxinidae) was analyzed by the primer walking method. Its mitogenome was 18,862 bp in total length and was composed of 13 protein-coding genes, two ribosomal RNA genes, and 22 transfer RNA genes. The gene content and order were congruent with those of typical vertebrates. In the phylogenetic tree, M. fernholmi showed the closest relationship to M. glutinosa in the same genus and subfamily and well separated from the other hagfish in the subfamily Eptatretinae.

Women with Endometriosis, Especially Those Who Conceived with Assisted Reproductive Technology, Have Increased Risk of Placenta Previa: Meta-analyses.

BACKGROUND: Many women with endometriosis have become pregnant through assisted reproductive technology (ART), and have often experienced placenta previa (PP) during pregnancy. The objective of this study was to assess the association between women with endometriosis, especially those who conceived with ART, and the risk of PP. METHODS: Two reviewers independently determined studies that were considered suitable for meta-analyses published in various medicine-related databases from March 1, 2004 through July 31, 2017 without language restrictions. Eight studies met the inclusion criteria, with a combined sample size of 21,930 women. Of these 21,930 pregnancies, 6,256 had endometriosis (endometriosis) and 15,674 had no endometriosis. Four of these studies included 8,161 women who conceived with ART, 1,640 of whom had endometriosis (endometriosis + ART), and 6,521 of whom did not have endometriosis. Meta-analyses were estimated with odds ratios (ORs) and 95% confidence intervals (CIs) using random effect analysis according to heterogeneity of studies. RESULTS: These meta-analyses showed women with endometriosis (endometriosis) have an increased risk of PP (OR, 4.038; 95% CI, 2.291-7.116; P = 0.000). These results showed women who conceived with ART (endometriosis + ART), have a substantially increased risk of PP (OR, 5.543; 95% CI, 1.659-18.523; P = 0.005). CONCLUSION: These meta-analyses demonstrate women with endometriosis have an increased risk of PP.

A case report of successful pregnancy and delivery after peritoneal dialysis in a patient misdiagnosed with primary infertility.

RATIONALE: Currently, 15% of women in fertility age are infertile and the frequency is increasing. Among the various causes of infertility, end-stage renal disease (ESRD) has been shown to decrease the frequency of pregnancies compared with normal females. However, dialysis of patients with ESRD increases the likelihood of pregnancy.Herein, we report successful pregnancy and delivery after peritoneal dialysis in a patient who was misdiagnosed as primary infertility. PATIENT CONCERNS: A 37-year-old female who was unaware of her ESRD was misdiagnosed with primary infertility. After undergoing artificial insemination, she was referred to department of internal medicine because of generalized edema, dyspnea, nausea, vomiting, and poor oral intake. After evaluation, she was diagnosed with ESRD and initiated peritoneal dialysis. DIAGNOSES: The patients was on peritoneal dialysis for a year and discovered that she was pregnant. INTERVENTIONS: During pregnancy, the patient maintained a residual urine output, BUN levels below 50 mg/dL, controlled blood pressure and a targeted hemoglobin range. She obtained adequate calories and protein and was managed by a multidisciplinary team. OUTCOMES: The patient delivered a preterm male baby with no anomalies. LESSONS: ESRD should also be considered among the several causes of infertility in fertile women. If ESRD is the cause of infertility, the frequency of pregnancy increases following dialysis. If pregnancy is diagnosed early, intensive renal replacement therapy, adequate nutritional intake and regular fetal monitoring during pregnancy increase the chances of successful delivery while maintaining PD.

Quantitative ultrastructural analysis of fibers expressing parvalbumin, calretinin, calbindin D-28k, stage specific embryonic antigen-4, and phosphorylated neurofilament 200 in the peripheral sensory root of the rat trigeminal ganglion.

Parvalbumin (PV), calretinin (CR), calbindin D-28k (CB), stage specific embryonic antigen-4 (SSEA4), and phosphorylated neurofilament 200 (pNF200) have been commonly used as markers for primary afferent neurons with large myelinated (A) fibers but detailed information on the expression of these markers in specific primary afferent fiber types is still lacking. We here examined the fibers that express PV, CR, CB, SSEA4, and pNF200 in the trigeminal ganglion and its peripheral sensory root by light- and electron-microscopic immunohistochemistry and quantitative analysis. We found that all CR-immunopositive (+), CB+, and SSEA4+ fibers and virtually all (98.8%) PV+ fibers were myelinated, most CR+ fibers were large myelinated, whereas most CB+ and SSEA4+ fibers were small myelinated. One half of the PV+ fibers were small myelinated and the other half were large myelinated. Of all pNF200+ fibers, about a third each were small myelinated, large myelinated, and unmyelinated. These findings suggest that PV, CR, CB, and SSEA4 can be used as specific markers for primary afferent neurons with myelinated fibers, but that pNF200 is not suitable as a specific marker for primary afferent neurons with myelinated fibers, and also raise the possibility that PV, CR, CB, and SSEA4 may be expressed in both mechanoreceptive and nociceptive neurons.