Editorial: Mechanisms of Orofacial Pain and Sex Differences

Oral behaviors and anxiety are significant predictors of jaw function limitation in patients with anterior disc displacement without reduction

OBJECTIVE

We aimed to describe jaw function characteristics in patients with anterior disc displacement without reduction (ADDWoR) using the jaw function limitation scale (JFLS), and to investigate the effects of biopsychosocial risk factors on limited jaw function.

DESIGN

In this cross-sectional study of 636 patients with ADDWoR (females, 568; males, 68), we used the JFLS to assess jaw function. Behavioral, psychological, sociodemographic, and biomedical data were collected. Multivariate logistic regression analysis was used to determine risk factors affecting limited jaw function. A receiver operating characteristic curve was used to evaluate the predictive effect of these risk factors.

RESULTS

ADDWoR-associated limitations included restricted jaw mobility and mastication, which exceeded median global functional limitations scale scores, especially mouth opening to bite an apple and chewing tough food. Females had greater limitations in jaw mobility, verbal and emotional communication, and overall. Multivariate logistic regression analysis findings indicated that oral behaviors, anxiety, sex, pain intensity, and maximal mouth opening (MMO) were predictive of limited jaw function (area under the curve, 72 %).

CONCLUSION

Patients with ADDWoR reported mastication and jaw mobility restrictions, with females having more pronounced limitations, and specific risk factors identified as significant predictors of jaw function limitations. Along with pain relief and improvement in MMO, appropriate psychological counseling and oral behavioral correction facilitates recovery of jaw function in such patients.

Predictors of Non-Rhinogenic Facial Pain or Pressure in Otolaryngology Clinic

OBJECTIVES

Identify demographic and clinical characteristics that may help differentiate non-rhinogenic facial pain or pressure (NRFP) from sinusitis.

STUDY DESIGN

Retrospective single-institution study.

SETTING

Tertiary Care Center Rhinology Clinic.

METHODS

All patients presenting with a complaint of facial pain or pressure over a 3-year period were included. Patients were categorized into either NRFP or sinusitis groups based on computed tomography imaging and nasal endoscopy. Data pertaining to demographics, history, and SNOT-22 questionnaire domains were compared via univariate analysis as well as logistic regression with backwards variable selection.

RESULTS

A total of 296 patients met inclusion criteria, of which 128 had NRFP and 168 had sinusitis. A significantly greater percentage of patients in the NRFP group were women of childbearing age (40.6% vs 28.0%, P = .02). Backwards variable selection resulted in a model with four variables predicting a diagnosis of NRFP-female sex (odds ratio [OR] = 2.998, P < .0001), no history of prior sinonasal surgery (OR = 0.340 for history vs no history, P < .01), low nasal domain score (OR = 0.551, P < .0001), and high ear/facial domain score (OR = 1.453, P < .01).

CONCLUSION

Accurately identifying patients with NRFP at initial presentation based on history would help direct patients to the appropriate care pathway and prevent ineffective treatments such as antibiotics and sinus procedures. Our findings suggest that the suspicion for NRFP should be higher in women of child-bearing age as well as patients with greater ear/facial symptoms or lesser nasal symptoms.

Sex-dependent differences in the genomic profile of lingual sensory neurons in naïve and tongue-tumor bearing mice

Mechanisms of sex-dependent orofacial pain are widely understudied. A significant gap in knowledge exists about comprehensive regulation of tissue-specific trigeminal sensory neurons in diseased state of both sexes. Using RNA sequencing of FACS sorted retro-labeled sensory neurons innervating tongue tissue, we determined changes in transcriptomic profiles in males and female mice under naïve as well as tongue-tumor bearing conditions Our data revealed the following interesting findings: (1) FACS sorting obtained higher number of neurons from female trigeminal ganglia (TG) compared to males; (2) Naïve female neurons innervating the tongue expressed immune cell markers such as Csf1R, C1qa and others, that weren't expressed in males. This was validated by Immunohistochemistry. (3) Accordingly, immune cell markers such as Csf1 exclusively sensitized TRPV1 responses in female TG neurons. (4) Male neurons were more tightly regulated than female neurons upon tumor growth and very few differentially expressed genes (DEGs) overlapped between the sexes, (5) Male DEGs contained higher number of transcription factors whereas female DEGs contained higher number of enzymes, cytokines and chemokines. Collectively, this is the first study to characterize the effect of sex as well as of tongue-tumor on global gene expression, pathways and molecular function of tongue-innervating sensory neurons.

Sex-dependent Differences in the Genomic Profile of Lingual Sensory Neurons in Naïve and Tongue-Tumor Bearing Mice

Mechanisms of sex-dependent orofacial pain are widely understudied. A significant gap in knowledge exists about comprehensive regulation of tissue-specific trigeminal sensory neurons in diseased state of both sexes. Using RNA sequencing of FACS sorted retro-labeled sensory neurons innervating tongue tissue, we determined changes in transcriptomic profiles in males and female mice under naïve as well as tongue-tumor bearing conditions Our data revealed the following interesting findings: 1) Tongue tissue of female mice was innervated with higher number of trigeminal neurons compared to males; 2) Naïve female neurons innervating the tongue exclusively expressed immune cell markers such as Csf1R, C1qa and others, that weren't expressed in males. This was validated by Immunohistochemistry. 4) Accordingly, immune cell markers such as Csf1 exclusively sensitized TRPV1 responses in female TG neurons. 3) Male neurons were more tightly regulated than female neurons upon tumor growth and very few differentially expressed genes (DEGs) overlapped between the sexes, 5) Male DEGs contained higher number of transcription factors whereas female DEGs contained higher number of enzymes, cytokines and chemokines. Collectively, this is the first study to characterize the effect of sex as well as of tongue-tumor on global gene expression, pathways and molecular function of tongue-innervating sensory neurons.

Cannabis Bioactive Compound-Based Formulations: New Perspectives for the Management of Orofacial Pain

The management of orofacial pain to alleviate the quality of life of affected patients is becoming increasingly challenging for scientific research and healthcare professionals. From this perspective, in addition to conventional therapies, new alternatives are being sought, increasingly looking at the use of both natural and synthetic products. Cannabis sativa L. represents an interesting source of bioactive compounds, including non-psychoactive cannabinoids, flavonoids, and terpenes, many of which are effective in improving pain intensity. Here, we aim to analyze the possible mechanisms of action of the bioactive natural and synthetic hemp-derived compounds responsible for the modulatory effects on pain-related pathways. The ability of these compounds to act on multiple mechanisms through a synergistic effect, reducing both the release of inflammatory mediators and regulating the response of the endocannabinoid system, makes them interesting agents for alternative formulations to be used in orofacial pain.