Effects of seasonal differences in testosterone and cortisol levels on pain responses under resting and anxiety conditions

Effects of physical activity levels on characteristic pain in temporomandibular dysfunctions: a cross-sectional study

BACKGROUND

Physical activity is known to influence the symptoms of a variety of pain disorders including fibromyalgia and osteoarthritis although the underlying mechanism is not fully understood. In spite of the high prevalence of temporomandibular disorders (TMD), no previous study has objectively evaluated the relationship between TMD and general physical activity. This study aims to investigate the influence of physical activity on pain and disability from TMD, considering various confounders including sleep, systemic inflammation, psychosocial disturbances, and widespread pain.

METHODS

This observational cross-sectional study is based on consecutive samples of 100 TMD patients (22 with high pain disability and 78 with low pain disability level). Physical activity levels were assessed with actigraph. Level of pain and disability were evaluated using the Graded Chronic Pain Scale. Hematologic examinations including inflammatory biomarkers were assessed and comorbidities were investigated with validated questionnaires. Differences were analyzed according to disability level.

RESULTS

Patients with high disability level spent significantly more time doing both moderate (p = 0.033) and vigorous (p = 0.039) level physical activity. Light physical activity, on the other hand, was associated with low disability but the difference did not reach statistical significance. Time spent in light physical activity was significantly associated with high levels of pain and disability (p = 0.026, β = -0.001) and time spent in vigorous physical activity had significant predictive power (cutoff value 2.5 min per week, AUC 0.643, p = 0.041). Scores of the Jaw Function Limitation Score-20 (p = 0.001), present McGill Pain Score (p = 0.010), and number of people potentially diagnosed with fibromyalgia (p = 0.033) were significantly higher in the high disability group.

CONCLUSIONS

Moderate or vigorous physical activity is associated with worse TMD symptoms while light physical activity may be beneficial. Further research related to the amount and frequency of physical activity is necessary to establish clinical guidelines for TMD.

TRIAL REGISTRATION

clinical trial registration of the Clinical Research Information Service of Republic of Korea (number KCT0007107).

Exploring Non-Invasive Salivary Biomarkers for Acute Pain Diagnostics: A Comprehensive Review

Pain is one of the most common complaints leading to a pediatric emergency department visit and is associated with various painful procedures, leading to increased anxiety and stress. Assessing and treating pain in children can be challenging, so it is crucial to investigate new methods for pain diagnosis. The review aims to summarize the literature on non-invasive salivary biomarkers, such as proteins and hormones, for pain assessment in urgent pediatric care settings. Eligible studies were those that included novel protein and hormone biomarkers in acute pain diagnostics and were not older than 10 years. Chronic pain studies were excluded. Further, articles were divided into two groups: studies in adults and studies in children (<18 years). The following characteristics were extracted and summarized: study author, enrollment date, study location, patient age, study type, number of cases and groups, as well as tested biomarkers. Salivary biomarkers, such as cortisol, salivary α-amylase, and immunoglobulins, among others, could be appropriate for children as saliva collection is painless. However, hormonal levels can differ among children in different developmental stages and with various health conditions, with no predetermined levels of saliva. Thus, further exploration of biomarkers in pain diagnostics is still necessary.

Testosterone protects against the development of widespread muscle pain in mice

Chronic widespread pain conditions are more prevalent in women than men, suggesting a role for gonadal hormones in the observed differences. Previously, we showed that female mice, compared to male, develop widespread, more severe, and longer-duration hyperalgesia in a model of activity-induced muscle pain. We hypothesized testosterone protects males from developing the female pain phenotype. We tested whether orchiectomy of males before induction of an activity-induced pain model produced a female phenotype and whether testosterone administration produced a male phenotype in females. Orchiectomy produced longer-lasting, more widespread hyperalgesia, similar to females. Administration of testosterone to females or orchiectomized males produced unilateral, shorter-lasting hyperalgesia. Prior studies show that the serotonin transporter (SERT) is increased in the nucleus raphe magnus (NRM) in models of chronic pain, and that blockade of SERT in the NRM reduces hyperalgesia. We examined potential sex differences in the distribution of SERT across brain sites involved in nociceptive processing using immunohistochemistry. A sex difference in SERT was found in the NRM in the activity-induced pain model; females had greater SERT immunoreactivity than males. This suggests that testosterone protects against development of widespread, long-lasting muscle pain and that alterations in SERT may underlie the sex differences.

Dexmedetomidine combined with suprascapular nerve block and axillary nerve block has a synergistic effect on relieving postoperative pain after arthroscopic rotator cuff repair

PURPOSE

Suprascapular nerve block (SSNB) is the most commonly used block for the relief of postoperative pain from arthroscopic rotator cuff repair and can be used in combination with axillary nerve block (ANB). Dexmedetomidine (DEX) is a type of alpha agonist that can elongate the duration of regional block. The aim of this study was to compare the effects of the use of dexmedetomidine combined with SSNB and ANB with those of the use of SSNB and ANB alone on postoperative pain, satisfaction, and pain-related cytokines within the first 48 h after arthroscopic rotator cuff repair.

METHODS

Forty patients with rotator cuff tears who had undergone arthroscopic rotator cuff repair were enrolled in this single-center, double-blinded randomized controlled trial study. Twenty patients were randomly allocated to group 1 and received ultrasound-guided SSNB and ANB using a mixture of 0.5 ml (50 μg) of DEX and 9.5 ml of 0.75% ropivacaine preemptively. The other 20 patients were allocated to group 2 and underwent ultrasound-guided SSNB and ANB alone using a mixture of 0.5 ml of normal saline and 9.5 ml of ropivacaine. The visual analog scale (VAS) for pain and patient satisfaction (SAT) scores were postoperatively checked within 48 h. The plasma interleukin (IL)-6, IL-8, IL-1β, cortisol, and serotonin levels were also postoperatively measured within 48 h.

RESULTS

Group 1 showed a significantly lower mean VAS (visual analog scale of pain) score 1, 3, 6, 12, 18 and 24 h after operation, and a significantly higher mean SAT (patient satisfaction) score 1, 3, 6, 12, 18, 24 and 36 h after the operation than group 2. Group 1 showed a significantly lower mean plasma IL-8 level 1 and 48 h after the operation, and a significantly lower mean IL-1β level 48 h after the operation than group 2. Group 1 showed a significantly lower mean plasma serotonin level 12 h after the operation than group 2. The mean timing of rebound pain in group 1 was significantly later than that in group 2 (36 h > 23 h, p = 0.007). Six patients each in groups 1 and 2 showed rebound pain. The others did not show rebound pain.

CONCLUSIONS

Ultrasound-guided SSNA and ANB with DEX during arthroscopic rotator cuff repair resulted in a significantly lower mean VAS score and a significantly higher mean SAT score within 48 h after the operation than SSNB and ANB alone. Additionally, SSNB and ANB with DEX tended to result in a later mean timing of rebound pain accompanied by significant changes in IL-8, IL-1β, and serotonin levels within 48 h after the operation. The present study could provide the basis for selecting objective parameters of postoperative pain in deciding the optimal use of medication for relieving pain.

LEVEL OF EVIDENCE

Level I.

TRIAL REGISTRATION

2015-20, ClinicalTrials.gov Identifier: NCT04398589.

IRB NUMBER

2015-20, Hallym University Chuncheon Sacred Heart Hospital.

Dexmedetomidine combined with interscalene brachial plexus block has a synergistic effect on relieving postoperative pain after arthroscopic rotator cuff repair

PURPOSE

Interscalene brachial plexus block (ISB) is one of the most commonly used regional blocks in relieving postoperative pain after arthroscopic rotator cuff repair. Dexmedetomidine (DEX) is an alpha 2 agonist that can enhance the effect of regional blocks. The aim of this study was to compare the effects of DEX combined with ISB with ISB alone on postoperative pain, satisfaction, and pain-related cytokines within the first 48 h after arthroscopic rotator cuff repair.

METHODS

Fifty patients with rotator cuff tears who had undergone arthroscopic rotator cuff repair were enrolled in this single center, double-blinded randomized controlled trial study. Twenty-five patients were randomly allocated to group 1 and received ultrasound-guided ISB using a mixture of 1 ml (100 μg) of DEX and 8 ml of 0.75% ropivacaine preemptively. The other 25 patients were allocated to group 2 and underwent ultrasound-guided ISB alone using a mixture of 1 ml of normal saline and 8 ml of ropivacaine. The visual analog scale (VAS) for pain and patient satisfaction (SAT) scores were checked within 48 h postoperatively. The plasma interleukin (IL)-6, -8, -1β, cortisol, and substance P levels were also measured within 48 h, postoperatively.

RESULTS

Group 1 showed a significantly lower mean VAS score and a significantly higher mean SAT score than group 2 at 1, 3, 6, 12, and 18 h postoperatively. Compared with group 2, group 1 showed a significantly lower mean plasma IL-6 level at 1, 6, 12, and 48 h postoperatively and a significantly lower mean IL-8 level at 1, 6, 12, 24, and 48 h postoperatively. The mean timing of rebound pain in group 1 was significantly later than that in group 2 (12.7 h > 9.4 h, p = 0.006).

CONCLUSIONS

Ultrasound-guided ISB with DEX in arthroscopic rotator cuff repair led to a significantly lower mean VAS score and a significantly higher mean SAT score within 48 h postoperatively than ISB alone. In addition, ISB with DEX showed lower mean plasma IL-6 and IL-8 levels than ISB alone within 48 h postoperatively, with delayed rebound pain.

LEVEL OF EVIDENCE

I.

TRIAL REGISTRATION

2013-112, ClinicalTrials.gov Identifier: NCT02766556.

Testosterone-cortisol dissociation in children exposed to prenatal maternal stress, and relationship with aggression: Project Ice Storm

Prenatal maternal stress (PNMS) has been associated with postnatal behavioral alterations that may be partly explained by interactions between the hypothalamic-pituitary-adrenal (HPA) and hypothalamic-pituitary-gonadal (HPG) axes. Yet it remains unclear whether PNMS leads to enduring HPA-HPG alterations in the offspring, and whether HPA-HPG interactions can impact behavior during development, in particular levels of aggression in childhood. Here we investigated the relationship between a marker for HPG axis function (baseline testosterone) and a marker for HPA axis response (cortisol area under the curve) in 11½-year-olds whose mothers were exposed to the 1998 Quebec ice storm during pregnancy (n = 59 children; 31 boys, 28 girls). We examined (a) whether the degree of objective or subjective PNMS regulates the testosterone-cortisol relationship at age 11½, and (b) whether this testosterone-cortisol relationship is associated with differences in aggressive behavior. We found that, at lower levels of subjective PNMS, baseline testosterone and cortisol reactivity were positively correlated; in contrast, there was no relationship between these hormones at higher levels of subjective PNMS. Cortisol response moderated the relationship between testosterone and aggression. These results support the notion PNMS may explain variance in fetal HPA-HPG interactions, and that these interactions may be associated with aggressive behavior in late childhood.

Testosterone effects on pain and brain activation patterns

BACKGROUND

This study investigated whether pain and pain-related unpleasantness ratings were altered by blood testosterone levels. We also investigated whether activation of brain regions that represent pain intensity [primary somatosensory cortex (S1)] and pain-related unpleasantness [perigenual ACC (pACC) and orbitofrontal cortex (OFC)] were affected by blood testosterone levels.

METHODS

Twenty-six healthy men were recruited. Blood testosterone levels were measured before fMRI scanning. The participants were classified into two groups (high vs. low testosterone) according to their blood testosterone level (each group n = 13). The middle finger was immersed in a 50°C water bath (50°C, 30 s, five times) to induce identical noxious stimulation in all participants.

RESULTS

The low testosterone group showed statistically significantly higher pain (P = 0.047), unpleasantness (P = 0.047), anxiety (P = 0.015), and fear ratings (P = 0.01) than the high testosterone group. Fear rating increased as pain rating rose and as testosterone level decreased (P < 0.001). When participants received noxious stimulation, the pACC and OFC were more highly activated in the low testosterone group compared to the high testosterone group. Activation of S1, a region related to pain intensity, did not differ between both groups.

CONCLUSION

Compared to the high testosterone group, the low testosterone group had significant activation in the pACC and OFC, regions that represent pain-related unpleasantness, but not in S1 that represents pain intensity, leading to higher pain ratings. These findings emphasize the importance of considering the effects of testosterone levels when treating patients.

Step-down vs. step-up noxious stimulation: differential effects on pain perception and patterns of brain activation

BACKGROUND

We hypothesize that pain and brain responses are affected by changes in the presentation sequence of noxious stimuli that are, overall, identical in intensity and duration.

METHODS

During functional magnetic resonance imaging (fMRI) scanning, 21 participants experienced three patterns of noxious stimulation: Up-type (step-up noxious stimulation, 15 s), Down-type (step-down noxious stimulation, 15 s), and Down-up-type (decreasing and increasing pattern of noxious stimulation, 15 s). The total intensity and duration of the three noxious stimulation patterns were identical, but the stimulation sequences were different.

RESULTS

Pain and unpleasantness ratings in the Down- and Down-up-type noxious stimulations were lower than in the Up-type noxious stimulation. The left prefrontal cortex [(PFC, BA (Brodmann area) 10, (-45, 50, 1)] was more highly activated in the Down- and Down-up-type noxious stimulations than in the Up-type noxious stimulation. The S1, S2, insula, bilateral PFC (BA 46), and midcingulate cortex were more highly activated in the Up-type noxious stimulation than in the Down-type noxious stimulation. PFC BA 10 was located at an inferior level compared to the bilateral PFC BA 46 (Z axis = 1 for BA 10, compared to 22 and 25 for the right and left BA 46, respectively). When cortisol level was increased, the left hippocampal cortex, along with the left parahippocampal cortex, was greatly activated for the Up-type noxious stimulation.

CONCLUSION

When pain cannot be avoided in clinical practice, noxious stimuli should be applied to patients in a step-down pattern that delivers the most intense pain first and the least intense pain last.

Fibromyalgia symptoms and cirrhosis

BACKGROUND

An association between fibromyalgia and hepatitis C virus (HCV) has been previously described. However, the relationship between nonalcoholic steatohepatitis (NASH) and fibromyalgia symptoms has not been assessed, though they share several risk factors.

AIM

We aimed to assess the factors associated with fibromyalgia symptoms across etiologies of liver disease.

METHODS

Patients with cirrhosis due to HCV, NASH, or alcohol were recruited from an outpatient hepatology clinic and administered the Hospital Anxiety and Depression Score, Pittsburgh Sleep Quality Index, and the modified 2010 American College of Rheumatology Diagnostic Criteria for Fibromyalgia. Serum inflammatory markers were measured with standard luminex assays.

RESULTS

Of 193 participants, 53 (27 %) met criteria for fibromyalgia. Fibromyalgia symptoms were significantly associated with etiology of liver disease (HCV: 35 %, NASH: 30 %, alcohol-related liver disease: 12 %, p < 0.01). Using logistic regression, mood symptoms (OR 1.14, 95 % CI 1.06, 1.22), sleep disturbance (OR 1.32, 95 % CI 1.16, 1.52), and etiology of liver disease (NASH vs. HCV not different, alcohol vs. HCV OR 0.19, 95 % CI 0.05, 0.63) were associated with fibromyalgia symptoms. If abdominal pain was included in the model, etiology became nonsignificant, indicating that it may be central sensitization due to abdominal pain in patients with chronic liver disease that explains fibromyalgia symptoms rather than the etiology of liver disease or inflammation.

CONCLUSIONS

Fibromyalgia symptoms were significantly associated with HCV and NASH cirrhosis and with psychiatric symptoms. Future work should focus on the underlying pathophysiology and management of widespread pain in patients with cirrhosis.

Brain mechanisms of pain relief by transcutaneous electrical nerve stimulation: A functional magnetic resonance imaging study

BACKGROUND

Although the exact mechanism of TENS pain relief is unknown, it is believed that TENS impulses interrupt nociceptive signals at the dorsal horn of the spinal cord.

AIMS

To evaluate the hypotheses that during pain caused by noxious stimuli, brain responses, temporal summation and brain functional connectivity are modulated by TENS, and that mechanisms of pain relief by TENS differ between men and women.

METHODS

During fMRI scanning, the same noxious stimuli were delivered to each participant in pain-only and pain+TENS conditions. In the pain-only condition, noxious stimuli were presented without TENS. In the pain+TENS condition, participants received noxious stimuli and TENS concurrently. Participants were initially presented with TENS at an intensity that was just below that causing discomfort. TENS intensity was presented in a step-wise fashion to prevent temporal summation from repetitive noxious stimuli.

RESULTS

Pain and unpleasantness ratings were significantly higher in the pain-only than the pain+TENS condition. With non-painful TENS, primary and secondary somatosensory and parietal cortices were activated, and temporal summation from repetitive noxious stimuli was prevented. Periaqueductal gray (PAG) and lateral prefrontal cortex functional connectivity was increased by TENS, and modulated by testosterone and cortisol. Women reported greater pain during TENS than men, and showed greater activation in the temporoparietal junction cortex and increased PAG functional connectivity with the orbitofrontal cortex.

CONCLUSION

TENS led to pain reduction, probably due to activation of the descending pain-inhibitory pathway, indicating that this TENS method may be applied in clinical practice.