CC Chemokine Receptor 4 (CCR4) as a Possible New Target for Therapy.

Chemokines and their receptors participate in many biological processes, including the modulation of neuroimmune interactions. Approximately fifty chemokines are distinguished in humans, which are classified into four subfamilies based on the N-terminal conserved cysteine motifs: CXC, CC, C, and CX3C. Chemokines activate specific receptors localized on the surface of various immune and nervous cells. Approximately twenty chemokine receptors have been identified, and each of these receptors is a seven-transmembrane G-protein coupled receptor. Recent studies provide new evidence that CC chemokine receptor 4 (CCR4) is important in the pathogenesis of many diseases, such as diabetes, multiple sclerosis, asthma, dermatitis, and cancer. This review briefly characterizes CCR4 and its ligands (CCL17, CCL22, and CCL2), and their contributions to immunological and neoplastic diseases. The review notes a significant role of CCR4 in nociceptive transmission, especially in painful neuropathy, which accompanies many diseases. The pharmacological blockade of CCR4 seems beneficial because of its pain-relieving effects and its influence on opioid efficacy. The possibilities of using the CCL2/CCL17/CCL22/CCR4 axis as a target in new therapies for many diseases are also discussed.

CCR4 Antagonist (C021) Administration Diminishes Hypersensitivity and Enhances the Analgesic Potency of Morphine and Buprenorphine in a Mouse Model of Neuropathic Pain.

Neuropathic pain is a chronic condition that remains a major clinical problem owing to high resistance to available therapy. Recent studies have indicated that chemokine signaling pathways are crucial in the development of painful neuropathy; however, the involvement of CC chemokine receptor 4 (CCR4) has not been fully elucidated thus far. Therefore, the aim of our research was to investigate the role of CCR4 in the development of tactile and thermal hypersensitivity, the effectiveness of morphine/buprenorphine, and opioid-induced tolerance in mice exposed to chronic constriction injury (CCI) of the sciatic nerve. The results of our research demonstrated that a single intrathecal or intraperitoneal administration of C021, a CCR4 antagonist, dose dependently diminished neuropathic pain-related behaviors in CCI-exposed mice. After sciatic nerve injury, the spinal expression of CCL17 and CCL22 remained unchanged in contrast to that of CCL2, which was significantly upregulated until day 14 after CCI. Importantly, our results provide evidence that in naive mice, CCL2 may evoke pain-related behaviors through CCR4 because its pronociceptive effects are diminished by C021. In CCI-exposed mice, the pharmacological blockade of CCR4 enhanced the analgesic properties of morphine/buprenorphine and delayed the development of morphine-induced tolerance, which was associated with the silencing of IBA-1 activation in cells and decrease in CCL2 production. The obtained data suggest that the pharmacological blockade of CCR4 may be a new potential therapeutic target for neuropathic pain polytherapy.

Novel hybrid compounds, opioid agonist+melanocortin 4 receptor antagonist, as efficient analgesics in mouse chronic constriction injury model of neuropathic pain.

When the nerve tissue is injured, endogenous agonist of melanocortin type 4 (MC4) receptor, α-MSH, exerts tonic pronociceptive action in the central nervous system, contributing to sustaining the neuropathic pain state and counteracting the analgesic effects of exogenous opioids. With the intent of enhancing opioid analgesia in neuropathy by blocking the MC4 activation, so-called parent compounds (opioid agonist, MC4 antagonist) were joined together using various linkers to create novel bifunctional hybrid compounds. Analgesic action of four hybrids was tested after intrathecal (i.t.) administration in mouse models of acute and neuropathic pain (chronic constriction injury model, CCI). Under nerve injury conditions, one of the hybrids, UW3, induced analgesia in 1500 times lower i.t. dose than the opioid parent (ED50: 0.0002 nmol for the hybrid, 0.3 nmol for the opioid parent) and in an over 16000 times lower dose than the MC4 parent (ED50: 3.33 nmol) as measured by the von Frey test. Two selected hybrids were tested for analgesic properties in CCI mice after intravenous (i.v.) and intraperitoneal (i.p.) administration. Opioid receptor antagonists and MC4 receptor agonists diminished the analgesic action of these two hybrids studied, though the extent of this effect differed between the hybrids; this suggests that linker is of key importance here. Further results indicate a significant advantage of hybrid compounds over the physical mixture of individual pharmacophores in their analgesic effect. All this evidence justifies the idea of synthesizing a bifunctional opioid agonist-linker-MC4 antagonist compound, as such structure may bring important benefits in neuropathic pain treatment.

Blockade of CCR4 Diminishes Hypersensitivity and Enhances Opioid Analgesia - Evidence from a Mouse Model of Diabetic Neuropathy.

Chemokine signaling has been implicated in the pathogenesis of diabetic neuropathy; however, the role of chemokine CC motif receptor 4 (CCR4) remains unknown. The goal was to examine the function of CCR4 in hypersensitivity development and opioid effectiveness in diabetic neuropathy. Streptozotocin (STZ; 200 mg/kg, intraperitoneally administered)-induced mouse model of diabetic neuropathy were used. An analysis of the mRNA/protein expression of CCR4 and its ligands was performed by qRT-PCR, microarray and/or Western blot methods. C021 (CCR4 antagonist), morphine and buprenorphine were injected intrathecally or intraperitoneally, and pain-related behavior was evaluated by the von Frey, cold plate and rotarod tests. We observed that on day 7 after STZ administration, the blood glucose level was increased, and as a consequence, hypersensitivity to tactile and thermal stimuli developed. In addition, we observed an increase in the mRNA level of CCL2 but not CCL17/CCL22. The microarray technique showed that the CCL2 protein level was also upregulated. In naive mice, the pronociceptive effect of intrathecally injected CCL2 was blocked by C021, suggesting that this chemokine acts through CCR4. Importantly, our results provide the first evidence that in a mouse model of diabetic neuropathy, single intrathecal and intraperitoneal injections of C021 diminished neuropathic pain-related behavior in a dose-dependent manner and improved motor functions. Moreover, both single intrathecal and intraperitoneal injections of C021 enhanced morphine and buprenorphine effectiveness. These results reveal that pharmacological modulation of CCR4 may be a good potential therapeutic target for the treatment of diabetic neuropathy and may enhance the effectiveness of opioids.

CCR4 antagonist (C021) influences the level of nociceptive factors and enhances the analgesic potency of morphine in a rat model of neuropathic pain.

Neuropathic pain is a chronic condition which significantly reduces the quality of life and serious clinical issue that is in general resistant to available therapies. Therefore looking for new analgesics is still critical issue. Recent, studies have indicated that chemokine signaling pathways are crucial for the development of neuropathy; however, the role of CC chemokine receptor 4 (CCR4) in this process has not yet been studied. Therefore, the aim of our research was to investigate the influence of C021 (a CCR4 antagonist) and CCR4 CC chemokine ligands 17 and 22 (CCL17 and CCL22) on the development of hypersensitivity and the effectiveness of morphine induced analgesia in naive animals and/or animals exposed to chronic constriction injury (CCI) of the sciatic nerve. Firstly, we demonstrated that the intrathecal administration of CCL17 and CCL22 induced pain-related behavior in naive mice. Secondly, we revealed that the intrathecal injection of C021 significantly reduced CCI-induced hypersensitivity after nerve injury. In parallel, C021 reduced microglia/macrophages activation and the level of some pronociceptive interleukins (IL-1beta; IL-18) in the spinal cord 8 days after CCI. Moreover, C021 not only attenuated mechanical and thermal hypersensitivity but also enhanced the analgesic properties of morphine. Our research indicates that CCR4 ligands might be important factors in the early stages of neuropathy, when we observe intense microglia/macrophages activation. Moreover, pharmacological blockade of CCR4 may serve as a potential new target for better understanding the mechanisms of neuropathic pain development.

Improvement in Gait Pattern After Knee Arthroplasty Followed by Proprioceptive Neuromuscular Facilitation Physiotherapy.

The aim of the study was to assess the influence of a physiotherapy program based on proprioceptive neuromuscular facilitation (PNF) on kinematic gait pattern after total knee arthroplasty. This comparative study included two groups of patients qualified for total surgical knee joint replacement due to osteoarthritis: a study group and a control group, either consisting of 28 patients of a matched age range of 55-90 years. Following surgery, 4 days after standard postoperative rehabilitation, the study patients were subjected to a 3-week-long therapist-assisted rehabilitation based on PNF principles (10 sessions of 75 min each), whereas control patients were discharged with instructions on how to exercise in the home setting. The outcome consisted of spatial-temporal gait parameters that were assessed at three time points: a day before surgery and then 1 month and 6 months after. The findings were that PNF caused substantial, sustained improvements in gait kinematics, shortening the stance phases, gait cycle duration, and double support phase and prolonging swing phase velocity, gait velocity, cadence, step length, and gait cycle length. Also, postsurgical pain was evidently less. We conclude that the individually tailored PNF rehabilitation program is superior compared to a standard recommendation of home-based physiotherapy in terms of improving gait kinematic pattern as well as psychological aspects related to pain perception in patients after knee arthroplasty.

Effectiveness of Proprioceptive Neuromuscular Facilitation (PNF) in Improving Shoulder Range of Motion. A Pilot Study.

[b]Background.[/b] Subacromial impingement syndrome is a condition of the shoulder girdle which limits daily activities. It is worth seeking fast and effective treatment options. The aim of this study was to assess the impact of single-session proprioceptive neuromuscular facilitation (PNF) therapy on the shoulder range of motion and pain level in patients with subacromial impingement syndrome.[b]Materials and methods. [/b]The experimental group consisted of 11 patients with subacromial impingement syndrome who had undergone therapy based on the PNF concept. A control group consisted of 12 patients with subacromial impingement syndrome who had undergone laser therapy, magnetic field therapy and local cryotherapy. Both before and after the therapeutic interventions, the painless passive and active ranges of abduction, flexion, and external and internal rotation of the shoulder joint were measured on the same day with the use of a goniometer and measuring tape. Patients also evaluated their pain levels. They were asked to fill in DASH questionnaires in order to evaluate their baseline functional status. Nonparametric tests were used for the statistical analysis.[b]Results:[/b] After single-session PNF therapy, the mean shoulder range of motion increased by 15° (active) and 14° (passive). Active abduction improved by 13° and passive abduction by 18°. The ranges of active and passive external rotation increased by 8° and 7°, respectively. Active and passive internal rotation increased by 4°. 73% of patients who underwent the therapy stated that their pain had decreased. The magnetic field therapy, laser therapy and cryotherapy alone did not contribute to increased ranges of motion.[b]Conclusions.[/b] 1. Subacromial impingement syndrome significantly limits function in daily life. 2. Single-session therapy with the use of the techniques and patterns of proprioceptive neuromuscular facilitation can improve both the active and passive range of shoulder movement. 3. Physiotherapy based on the PNF concept is positively perceived by patients. 4. Single sessions of magnetic field therapy, laser therapy and local cryotherapy do not improve the range of motion or diminish pain just after an intervention. 5. In the present study, the measuring tools were rather subjective. In the future, it is advisable to support the research claim in studies employing more objective research tools.