Fadolmidine - Favourable adverse effects profile for spinal analgesia suggested by in vitro and in vivo models

Modulation of spinal morphine pharmacokinetics and antinociception by α2-adrenergic agonists in the male rat

The synergistic antinociceptive effects of α2-adrenergic agonists and intrathecal (i.t.) opioids were initially linked to pharmacodynamics. However, the α2-agonist dexmedetomidine also enhances brain delivery of CSF-administered drugs by increasing glymphatic influx. Here, fadolmidine, a hydrophilic α2-agonist designed for spinal analgesia, was studied for its sedative, antinociceptive, and pharmacokinetic effects with co-administered lumbar intrathecal morphine. Subcutaneous and i.t. dexmedetomidine served as comparators. Forty-eight male Sprague-Dawley rats received i.t. lumbar catheters. Sedative effects of i.t. fadolmidine (1-10 μg) and i.t. dexmedetomidine (1-10 μg) were assessed by open field and rotarod tests. The antinociceptive effects of morphine alone (1.5 μg i.t.) and co-administered with i.t. fadolmidine (3 and 10 μg) were evaluated using the tail-flick test. Effects of i.t. fadolmidine and subcutaneous dexmedetomidine (0.2 mg/kg) on morphine concentration within CNS were assessed by liquid chromatography-tandem mass spectrometry at 60 min. While i.t. dexmedetomidine was sedating, i.t fadolmidine was not. The antinociceptive effects of other treatment regimens weaned at latest after 90 min, whereas the combination of fadolmidine 10 μg i.t. and morphine 1.5 μg i.t. provided antinociception until the end of the measurement period (%maximum possible effect of 77.5 ± 11.5 vs saline 10.6 ± 11.1, p = 0.0002 at 120 min). Subcutaneous dexmedetomidine effectively targeted lumbar morphine towards the injection site resulting in a 3335-fold (95% CI: 929-11978) lower brain-to-injection site ratio, versus a 355-fold (95% CI: 196-641) difference with saline. By improving spinal opioid targeting, α2-adrenergic agonists dexmedetomidine and fadolmidine may reduce supraspinal side effects, enabling safe and efficacious intrathecal analgesia.

Macrophage Polarization Towards M2 Phenotype by Curcuminoids Through NF-κB Pathway Inhibition in Adjuvant-Induced Arthritis

Macrophage polarization is decisive for homeostasis maintenance and tissue repair. Anti-inflammatory properties of curcumin (CUR) have been demonstrated in several studies. It used in the treatment of bone disorders includingrheumatoid arthritis. The present study aims to explore the potential mechanisms of curcumin on macrophage polarization, expression, activation, and cytokine secretion in adjuvant-induced arthritis as well as its possible role in enhancing the therapeutic action of methotrexate (MTX) together with minimizing MTX initiated side-effects. Rats were divided into eight groups as follows; Control group, MTX group: was weekly injected with MTX, CUR group: was treated with a daily oral dose of curcumin, MTX + CUR group: was treated with both methotrexate and curcumin, Adjuvant arthritis group (AIA): was injected with complete Freund's adjuvant for arthritis induction, AIA/MTX group: arthritic rats treated with methotrexate, AIA/CUR group: arthritic rats treated with curcumin and AIA/MTX + CUR: arthritic rats treated with both methotrexate and curcumin. Paw swelling, haematological analysis, immunological studies, histological observations and quantitative immunohistochemical investigations were performed. The present results showed that treating arthritic rats with curcumin either alone or in combination with methotrexate resulted in amelioration in paws inflammation, growth rate, absolute and relative spleen weights, and haematological analyses. Antinuclear antibodies, IL-1β, IL-8, IL-10, NF-kB levels, and CD68 + joint expression were also ameliorated. The microscopic examination of joint and spleen showed more improvement as apparently normal tissues in treated groups. It can be concluded that curcumin seems to be most promising in regulating macrophage expression, activation, cytokine secretion, and polarization, thus providing a novel insight in the application of curcumin-based treatments.

Anesthetic protocols for urodynamic studies of the lower urinary tract in small rodents-A systematic review

Urodynamic studies in rats and mice are broadly used to examine pathomechnisms of disease and identify and test therapeutic targets. This review aims to highlight the effects of the anesthetics on the lower urinary tract function and seeks to identify protocols that allow recovery from anesthesia and repeated measurements while preserving the function which is being studied. All studies published in English language, which compared the data obtained under various types of anesthesia and the urodynamics performed in awake animals were included. It appears that urethane, an anesthetic recommended extensively for the investigation of lower urinary tract function, is appropriate for acute urodynamic studies only. Major advantages of urethane are its stability and ability to preserve the micturition reflex. Due to its toxicity and carcinogenicity, urethane anesthesia should not be used for recovery procedures. This review evaluated available alternatives including propofol, isoflurane and combinations of urethane, ketamine/xylazine, ketamine/medetomidine, and/or fentanyl/fluanisone/midazolam. Different effects have been demonstrated among these drugs on the urinary bladder, the urethral sphincter, as well as on their neuroregulation. The lowest incidence of adverse effects was observed with the use of a combination of ketamine and xylazine. Although the variations in the reviewed study protocols represent a limitation, we believe that this summary will help in standardizing and optimizing future experiments.