Increase in peripheral benzodiazepine receptors on monocytes in fibromyalgia

Multitargeting the sleep-pain interaction with pharmacological approaches: A narrative review with suggestions on new avenues of investigation

The multimorbidity formed by sleep disturbances and pain conditions is highly prevalent and has a significant impact in global health and in the socioeconomic system. Although different approaches have been directed toward its management, evidence regarding an optimal treatment is lacking, and pharmacological options are often preferred. Health professionals (e.g., pain and sleep clinicians) tend to focus on their respective expertise, targeting a single symptom with a single drug. This may increase polypharmacy and the risk of drug interactions, adverse events, and mortality. Hence, the use of medications that can directly or indirectly improve sleep, pain, and other possible accompanying conditions without exacerbating them becomes especially relevant. The objectives of this comprehensive review are to: a) describe the beneficial or deleterious effects that some commonly used medications to manage pain have on sleep and sleep disorders; and b) describe the beneficial or deleterious effects that frequently prescribed medications for sleep may have on pain. Moreover, medications targeting some specific sleep-pain interactions will be suggested and future directions for improving sleep and alleviating pain of these patients will be provided with clinical and research perspectives.

Pain perception, blood pressure levels, and peripheral benzodiazepine receptors in patients followed for differentiated thyroid carcinoma: a longitudinal study in hypothyroidism and during hormone treatment

BACKGROUND

Elevated blood pressure levels that are associated with hypalgesia and hypothyroidism have major influences on the cardiovascular system. The potential modulation of pain sensitivity by thyroid hormones is largely undetermined. Moreover, a few experimental studies show that peripheral benzodiazepine receptors (PBRs), which may be altered in hypothyroidism, seem to be related with pain perception.

METHODS

Dental pain threshold and tolerance were evaluated in 19 patients followed for differentiated thyroid carcinoma (1) in severe short-term hypothyroidism (phase 1) and (2) during thyroid stimulating hormone-suppressive LT4 treatment (phase 2). PBR expression (cytofluorimetric evaluation) on peripheral blood mononuclear cells was also investigated in the 2 phases.

RESULTS

Pain perception differed throughout the study, the dental pain threshold was higher in phase 1 (P<0.05) whereas pain tolerance was higher but not significantly (P=0.07). Although the systolic blood pressure was higher during hypothyroidism (P<0.01), no relationship was found between blood pressure changes and pain sensitivity variations. Moreover, the multiple regression analysis showed an independent association of the clinical phase with pain sensitivity (r=-2.61, P=0.029), while accounting for systolic blood pressure. The intensity of PBRs was significantly higher in the first phase of the study (P=0.047) whereas the ratio did not significantly differ. However, no relationship was observed between pain sensitivity and PBRs.

DISCUSSION

In conclusion, in athyreotic patients, the pain sensitivity is related to the thyroid status and is independent of the increase in blood pressure induced by thyroid hormone deprivation. The PBRs do not seem to have major influence on pain sensitivity changes in hypothyroidism.

Peripheral benzodiazepine receptors on platelets of fibromyalgic patients

OBJECTIVE

The aim of the present study was to analyze if alterations of peripheral-type benzodiazepine receptor (PBR) characteristics occurred in platelet membranes of patients affected by primary fibromyalgia (FM).

DESIGN AND METHODS

Platelets were obtained from 30 patients with FM. Evaluation of kinetic parameters of PBR was performed using [(3)H] PK11195 as specific radioligand compared with 16 healthy volunteers.

RESULTS

The results showed a significant increase of PBR binding sites value in platelet membranes from FM patients (B(max) was 5366+/-188 fmol/mg vs. controls, 4193+/-341 fmol/mg, mean+/-SEM) (**p<0.01) but not for affinity value (K(d) was 4.90+/-0.39 nM vs. controls, 4.74+/-0.39 nM, mean+/-SEM) (p>0.05). Symptom severity scores (pain and tiredness) were positively correlated with B(max).

CONCLUSIONS

Our results showed an up-regulation of PBR in platelets of FM patients, and this seems to be related to the severity of fibromyalgic symptoms.

ADOA3R as a therapeutic target in experimental colitis: proof by validated high-density oligonucleotide microarray analysis

Adenosine A3 receptors (ADOA3Rs) are emerging as novel purinergic targets for treatment of inflammatory diseases. Our goal was to assess the protective effect of the ADOA3R agonist N(6)-(3-iodobenzyl)-adenosine-5-N-methyluronamide (IB-MECA) on gene dysregulation and injury in a rat chronic model of 2,4,6-trinitrobenzene sulfonic acid (TNBS)--induced colitis. It was necessary to develop and validate a microarray technique for testing the protective effects of purine-based drugs in experimental inflammatory bowel disease. High-density oligonucleotide microarray analysis of gene dysregulation was assessed in colons from normal, TNBS-treated (7 days), and oral IB-MECA-treated rats (1.5 mg/kg b.i.d.) using a rat RNU34 neural GeneChip of 724 genes and SYBR green polymerase chain reaction. Analysis included clinical evaluation, weight loss assessment, and electron paramagnetic resonance imaging/spin-trap monitoring of free radicals. Remarkable colitis-induced gene dysregulation occurs in the most exceptional cluster of 5.4% of the gene pool, revealing 2 modes of colitis-related dysregulation. Downregulation occurs in membrane transporter, mitogen-activated protein (MAP) kinase, and channel genes. Upregulation occurs in chemokine, cytokine/inflammatory, stress, growth factor, intracellular signaling, receptor, heat shock protein, retinoid metabolism, neural, remodeling, and redox-sensitive genes. Oral IB-MECA prevented dysregulation in 92% of these genes, histopathology, gut injury, and weight loss. IB-MECA or adenosine suppressed elevated free radicals in ex vivo inflamed gut. Oral IB-MECA blocked the colitis-induced upregulation (<or=20-fold) of Bzrp, P2X1R, P2X4R, P2X7R, P2Y2R, P2Y6R, and A2aR/A2bR but not A1R or A3R genes or downregulated P2X2R, P2Y1R, and P2Y4R. Real-time SYBR green polymerase chain reaction validated gene chip data for both induction of colitis and treatment with IB-MECA for >90% of genes tested (33 of 37 genes). We conclude that our validated high-density oligonucleotide microarray analysis is a powerful technique for molecular gene dysregulation studies to assess the beneficial effects of purine-based or other drugs in experimental colitis. ADOA3R is new potential therapeutic target for inflammatory bowel disease.