Browse by Audience
Pituitary adenylate cyclase-activating polypeptide (PACAP) has emerged as an important signaling peptide in migraine pathogenesis. Recently, we have shown that the less-abundant PACAP isoform, PACAP27, induced migraine and headache in patients equipotently to PACAP38. The present study examined the effect of PACAP27 on cerebral hemodynamics in healthy volunteers using high resolution magnetic resonance angiography (MRA). Eighteen healthy volunteers received infusion of PACAP27 (10 pmol/kg/min) or placebo over 20 min and were scanned repeatedly in fixed intervals for 5 hours in a double-blind, randomized, placebo-controlled study. The circumference of extra-intracerebral arteries was measured and compared with PACAP38 data. We found significant dilation of middle meningeal artery (MMA) (p = 0.019), superficial temporal artery (p = 0.001) and external carotid artery (p = 0.039) after PACAP27 infusion compared to placebo. Whereas the middle cerebral artery (MCA) (p = 0.011) and internal carotid artery (ICA) (p = 0.015, p = 0.019) were constricted. No effects on basilar artery (p = 0.708) and cavernous portion of ICA were found. Post hoc analyses revealed significant larger area under the curve for MMA after PACAP38 compared to PACAP27 (p = 0.033). We also found that PACAP27 induced headache in nine out of twelve (75%) volunteers and one (17%) after placebo. In conclusion, PACAP27 induced headache and dilated extracerebral arteries (>5 h) and slightly constricted MCA in healthy volunteers. Post hoc analysis of PACAP38 data compared with PACAP27 showed that PACAP isoforms dilates MMA with significantly different magnitude.
Learn More >Conditioned pain modulation (CPM) and offset analgesia are different features of descending pain inhibition. This study investigated CPM, offset analgesia and clinical pain measures in patients with knee osteoarthritis (KOA) before and after treatment with the combination of a non-steroidal anti-inflammatory drug (NSAIDs) plus acetaminophen.
Learn More >Throughout the world many people have both obesity and chronic pain, comorbidities that decrease Health-Related Quality of Life (HRQoL). It is uncertain whether patients with comorbid obesity can maintain improved HRQoL after Interdisciplinary Multimodal Pain Rehabilitation (IMMPR).
Learn More >Abnormal endogenous pain modulation (EPM) was suggested as a pathophysiological characteristic of chronic pain. EPM has been investigated using psychophysical tests for pain facilitation and inhibition such as temporal summation of pain and conditioned pain modulation, respectively. Another psychophysical test for pain inhibition is offset analgesia (OA), where small variations in noxious stimulus intensity over time elicit a disproportionately large analgesic response. OA has been investigated in patients with mixed pain conditions, but not in chronic temporomandibular disorders (TMD) patients.
Learn More >Cannabis is commonly used to manage chronic pain, but cannabis use patterns among individuals with chronic pain has not been well-characterized. We report cannabinoid, administration route, and product selection preferences among medical cannabis users with chronic pain from an ongoing, online survey. We also examined whether these preferences are affected by differences in sex, intentions behind use (medical only [MED] vs. medical + recreational [MEDREC]), and experience with cannabis (novice: <1 year vs. experienced: ≥1 year). 1,321 participants (59% female) completed the survey. 76.5% of participants used cannabis every day. 93.4% used 2 or more administration routes, with 72.5% using 3 or more. Female, MED, and novice users were less likely to smoke or vaporize (all p < 0.0001), but more likely to rank edibles, tinctures, and topicals as a first-choice administration route than their counterparts. Female and MED users also preferred low THC: high CBD ratios significantly more than their counterparts. Overall, only 2.6% of participants selected cannabis products with input from a medical professional, although 54.9% relied on advice from dispensary employees. More male, MEDREC, and experienced users selected products based on factors that reflected greater comfort with cannabis (e.g., smell, visual properties, cannabis variety). The wide variability in cannabis use among these different groups indicates the need for further research to investigate how specific use routines relate to clinical outcomes. Perspective: Medical cannabis users with chronic pain show distinct differences in cannabinoid preferences and administration associated with user sex, intentions behind use, and experience with cannabis. This article highlights the wide variability in cannabis preferences among medical cannabis users with chronic pain, which may be relevant for clinical outcomes.
Learn More >Patients with migraine frequently report ocular or visual symptoms including aura, photophobia, and eye pain. Using validated instruments, our group previously reported that due to these symptoms, patients have marked reductions in visual quality of life. In chronic migraine, these reductions can be as substantial as those reported for other neuro-ophthalmic diseases such as multiple sclerosis with optic neuritis and idiopathic intracranial hypertension. Because the instruments take several different dimensions into account, we were unable to determine which ocular symptom(s) contributed to reduced visual quality of life. The purpose of this investigation was to attempt to determine which ocular symptom(s) were driving the observed reduction in visual quality of life.
Learn More >Post-herpetic neuralgia (PHN) is a well-established clinical problem with potential severe personal and socioeconomic implications. GTP cyclohydrolase 1 (GCH1) gene, which encodes the rate-limiting enzyme in tetrahydrobiopterin synthesis, has been strongly implicated to be associated with neuropathic pain in previous animal and human studies. The rs3783641 (T > A) single-nucleotide polymorphism (SNP) in the GCH1 gene is functional. Here we examine the association between rs3783641 and PHN. A total of 292 subjects including 103 PHN patients, 87 herpes zoster (HZ) patients and 102 healthy controls were enrolled in this study. The rs3783641 polymorphisms were detected via the high-resolution melting curve (HRM) method. There were statistical differences between PHN group and the other two groups in genotype distribution (P = 0.029 and 0.017, respectively) and allele frequency (P = 0.032 and 0.005, respectively) of rs3783641. The proportion of subjects with AA genotype in the PHN group was significantly lower compared to HZ group and control group (P = 0.026 and 0.016, respectively). The frequency of A allele was lower in the PHN group than in control group (P = 0.005), and the frequency of T allele in the PHN group was higher than in HZ group and control group (P = 0.001 and 0.003, respectively). The results of this study suggest that the rs3783641 SNP in the GCH1 gene is associated with PHN, and the AA genotype showed a protective effect in PHN.
Learn More >Because of the pain and opioid epidemic in the United States, there is a need to update clinician's knowledge, attitudes, and beliefs regarding persistent pain across healthcare disciplines. The aim of this study was to determine if healthcare professionals can positively change their knowledge, attitudes, and beliefs regarding chronic pain, following a pain neuroscience education (PNE) lecture and one year follow-up.
Learn More >Efficacy of pain modulation is assessed as the difference in pain sensitivity during a painful conditioning, compared to before (conditioning pain modulation, CPM). Attention can be assessed with the Stroop-task, in which participants report the number of words on a screen; either congruent or incongruent with the value of the words. Attention away from painful stimuli during CPM enhances the CPM-effect. However, it is unknown if attention influences CPM-effects when the two are done in sequence.
Learn More >