Palmitoyl-glucosamine co-micronized with curcumin for maintenance of meloxicam-induced pain relief in dogs with osteoarthritis pain.

BACKGROUND: Osteoarthritis (OA) pain is the number one cause of chronic pain in dogs. Multimodal treatment, including combining safe and effective nutritional interventions with non-steroidal anti-inflammatory drugs (NSAIDs), is currently considered one of the most appropriate choices for managing OA pain. Palmitoyl-glucosamine is a feed material belonging to the ALIAmide family, whose parent molecule is the prohomeostatic lipid amide N-palmitoyl-ethanolamine. Curcumin is a promising plant antioxidant. The present study aimed at investigating whether 18-week dietary integration with palmitoyl-glucosamine co-micronized with curcumin was able to maintain pain relief in dogs with OA-associated chronic pain receiving meloxicam (1.5 mg/ml oral suspension) on a tapering regimen (progressive 25% decrease of the original 0.1 mg/kg/day dose, on a biweekly basis) during the first 8 weeks of treatment. Pain was assessed both by the owners and veterinary surgeons, with the first using both subjective evaluation and validated metrology instruments-i.e., Helsinki Chronic Pain Index (HCPI) and Canine Brief Pain Inventory (CBPI)-while the second rating the severity of lameness and pain on palpation on two previously used 5-point scales. RESULTS: A total of fifty-eight dogs with OA chronic pain entered the uncontrolled study. Pain on HCPI was considered severe at baseline (range 18-39). Based on owner's assessment, 90% of dogs who responded to meloxicam at the full-dose regimen could reduce meloxicam up to 25% of the original dose without experiencing pain worsening. Moreover, 75% of dogs was assessed as having no pain increase ten weeks after meloxicam withdrawal. A statistically significant decrease of pain severity as scored by HCPI (P < 0.0001) was observed two and ten weeks after meloxicam withdrawal compared to study entry (17.0 ± 1.05 and 15.1 ± 1.02, respectively, vs 29.0 ± 0.74; mean ± SEM). After meloxicam withdrawal, no statistically significant change in the CBPI scores was recorded. Pain on palpation and lameness significantly changed to less severe distributions along the study period (P < 0.0001). CONCLUSION: The findings appear to suggest that dietary integration with palmitoyl-glucosamine co-micronized with curcumin was able to maintain meloxicam-induced pain relief in dogs with severe OA chronic pain.

Effect of dietary supplementation with ultramicronized palmitoylethanolamide in maintaining remission in cats with nonflea hypersensitivity dermatitis: a double-blind, multicentre, randomized, placebo-controlled study.

BACKGROUND: Feline nonflea hypersensitivity dermatitis (NFHD) is a frequent cause of over-grooming, scratching and skin lesions. Multimodal therapy often is necessary. HYPOTHESIS/OBJECTIVES: To investigate the efficacy of ultramicronized palmitoylethanolamide (PEA-um) in maintaining methylprednisolone-induced remission in NFHD cats. ANIMALS: Fifty-seven NFHD cats with nonseasonal pruritus were enrolled originally, of which 25 completed all study requirements to be eligible for analysis. METHODS AND MATERIALS: Cats were randomly assigned to PEA-um (15 mg/kg per os, once daily; n = 29) or placebo (n = 28) while receiving a 28 day tapering methylprednisolone course. Cats responding favourably to methylprednisolone were then administered only PEA-um (n = 21) or placebo (n = 23) for another eight weeks, followed by a four week long treatment-free period. Cats were maintained in the study until relapse or study end, whichever came first. Primary outcome was time to relapse. Secondary outcomes were pruritus Visual Analog Scale (pVAS), SCORing Feline Allergic Dermatitis scale (SCORFAD) and owner Global Assessment Score (GAS). RESULTS: Mean relapse time was 40.5 days (±7.8 SE) in PEA-um treated cats (n = 13) and 22.2 days (±3.7 SE) for placebo (n = 12; P = 0.04). On Day 28, the severity of pruritus was lower in the PEA-um treated cats compared to placebo (P = 0.03). Mean worsening of pruritus at the final study day was lower in the PEA-um group compared to placebo (P = 0.04), whereas SCORFAD was not different between groups. Mean owner GAS at the final study day was better in the PEA-um than the placebo-treated group (P = 0.05). CONCLUSION AND CLINICAL IMPORTANCE: Ultramicronized palmitoylethanolamide could represent an effective and safe option to delay relapse in NFHD cats.

Expression of functional TRPV1 receptor in primary culture of canine keratinocytes.

The interest for the endovanilloid system and for transient receptor potential vanilloid 1 (TRPV1) is continuously increasing, due to their involvement in inflammation, nociception and pruritus. Even if TRPV1 enrolment was highlighted in both physiological and pathological conditions, some aspects remain unclear, mostly in veterinary medicine. This study aimed to verify the expression and functionality of TRPV1 in canine keratinocytes to investigate in vitro the role of TRPV1 in these cells that are involved in different cutaneous pathologies. Keratinocytes primary cultures were isolated from bioptical samples and cultivated. Binding assay (using 3 [H]-resiniferatoxin), displacement assay (in the presence of 1.2 nM 3 [H]-resiniferatoxin) and functional assays (in the presence of 1 µCi/45 Ca2+ ) with vanilloid agonists and antagonists, specifically addressed to TRPV1 receptor, were performed. Binding assay demonstrated the presence of measurable concentrations of TRPV1 (Bmax  = 1,240 ± 120 fmol/mg protein; Kd  = 0.01 ± 0.004 nM). Displacement assay highlighted the highest affinity for resiniferatoxin (RTX) and 5-iodo-resiniferatoxin (5-I-RTX), among agonists and antagonists, respectively. The same compounds results as the most potent in the functional assays. This study demonstrated the identification and the characterization of TRPV1 receptor in primary canine keratinocytes cultures. The results are promising for a clinical use, but further in vivo investigations are required.

Reply to: "Palmitoylethanolamide: problems regarding micronization, ultra-micronization and additives" Inflammopharmacology DOI:10.1007/s10787-014-0202-3.

This is a reply to a recently published Commentary: "Palmitoylethanolamide: problems regarding micronization, ultra-micronization and additives" Inflammopharmacology DOI: 10.1007/s10787-014-0202-3 , written in relation to our review article: Skaper SD, Facci L, Fusco M, della Valle MF, Zusso M, Costa B, Giusti P (2014) "Palmitoylethanolamide, a naturally occurring disease-modifying agent in neuropathic pain" Inflammopharmacology 22:79-94 DOI: 10.1007/s10787-013-0191-7 . We believe that the Commentary by Kriek contains a number of erroneous statements and misinterpretations of the published scientific/medical literature which our reply shall elaborate on. Further, the writer of the Commentary has a direct connection to a company, JP Russell Science Ltd that sells palmitoylethanolamide. The take-home message of our review remains as originally stated: "Collectively, the findings presented here propose that palmitoylethanolamide merits further consideration as a disease-modifying agent for controlling inflammatory responses and related chronic and neuropathic pain".

Increased levels of palmitoylethanolamide and other bioactive lipid mediators and enhanced local mast cell proliferation in canine atopic dermatitis.

BACKGROUND: Despite the precise pathogenesis of atopic dermatitis (AD) is unknown, an immune dysregulation that causes Th2-predominant inflammation and an intrinsic defect in skin barrier function are currently the two major hypotheses, according to the so-called outside-inside-outside model. Mast cells (MCs) are involved in AD both by releasing Th2 polarizing cytokines and generating pruritus symptoms through release of histamine and tryptase. A link between MCs and skin barrier defects was recently uncovered, with histamine being found to profoundly contribute to the skin barrier defects.Palmitoylethanolamide and related lipid mediators are endogenous bioactive compounds, considered to play a protective homeostatic role in many tissues: evidence collected so far shows that the anti-inflammatory effect of palmitoylethanolamide depends on the down-modulation of MC degranulation.Based on this background, the purpose of the present study was twofold: (a) to determine if the endogenous levels of palmitoylethanolamide and other bioactive lipid mediators are changed in the skin of AD dogs compared to healthy animals; (b) to examine if MC number is increased in the skin of AD dogs and, if so, whether it depends on MC in-situ proliferation. RESULTS: The amount of lipid extract expressed as percent of biopsy tissue weight was significantly reduced in AD skin while the levels of all analyzed bioactive lipid mediators were significantly elevated, with palmitoylethanolamide showing the highest increase.In dogs with AD, the number of MCs was significantly increased in both the subepidermal and the perifollicular compartments and their granule content was significantly decreased in the latter. Also, in situ proliferation of MCs was documented. CONCLUSIONS: The levels of palmitoylethanolamide and other bioactive lipid mediators were shown to increase in AD skin compared to healthy samples, leading to the hypothesis that they may be part of the body's innate mechanisms to maintain cellular homeostasis when faced with AD-related inflammation. In particular, the increase may be considered a temptative response to down-regulating the observed elevation in the number, functionality and proliferative state of MCs in the skin of AD dogs. Further studies are warranted to confirm the hypothesis.

Palmitoylethanolamide, a naturally occurring disease-modifying agent in neuropathic pain.

Persistent pain affects nearly half of all people seeking medical care in the US alone, and accounts for at least $80 billion worth of lost productivity each year. Among all types of chronic pain, neuropathic pain stands out: this is pain resulting from damage or disease of the somatosensory nervous system, and remains largely untreatable. With few available treatment options, neuropathic pain represents an area of significant and growing unmet medical need. Current treatment of peripheral neuropathic pain involves several drug classes, including opioids, gabapentinoids, antidepressants, antiepileptic drugs, local anesthetics and capsaicin. Even so, less than half of patients achieve partial relief. This review discusses a novel approach to neuropathic pain management, based on knowledge of: the role of glia and mast cells in pain and neuroinflammation; the body's innate mechanisms to maintain cellular homeostasis when faced with external stressors provoking, for example, inflammation. The discovery that palmitoylethanolamide, a member of the N-acylethanolamine family which is produced from the lipid bilayer on-demand, is capable of exerting anti-allodynic and anti-hyperalgesic effects by down-modulating both microglial and mast cell activity has led to the application of this fatty acid amide in several clinical studies of neuropathic pain, with beneficial outcome and no indication of adverse effects at pharmacological doses. Collectively, the findings presented here propose that palmitoylethanolamide merits further consideration as a disease-modifying agent for controlling inflammatory responses and related chronic and neuropathic pain.

Effects of a Protocol Combining a Non-Irritating Shampoo and an Adelmidrol-Based Adsorbent Mousse on Seborrhoea and Other Signs and Symptoms Secondary to Canine Atopic Dermatitis: A Multicenter, Open-Label Uncontrolled Clinical Trial.

The present study aimed at evaluating the effect of a gentle shampoo and a mousse containing Adelmidrol, tapioca starch and a non-prescription antimicrobial complex on seborrhoea and other clinical signs secondary to canine atopic dermatitis (cAD). Forty-six dogs with cAD-associated seborrhoea and/or pruritus > 4 cm on the pruritus visual analogue scale (P-VAS) and/or bacterial/Malassezia overgrowth were enrolled. The mousse was applied twice daily, and dogs were evaluated at days (D)0, 7, 14 and optionally 28, by means of a skin seborrheic index (SSI), P-VAS, cAD lesion index (CADLI), and a semiquantitative cytological score. The mean SSI value improved during the first two weeks (4.1 ± 0.37 to 1.9 ± 0.30; p < 0.0001). The mean P-VAS score (cm) decreased from 6.6 ± 0.19 at D0 to 3.8 ± 0.31 at D14 (p < 0.0001). The mean CADLI score dropped from 13.7 ± 1.24 to 8.5 ± 1.14 at D14 (p < 0.001). The cytological score for bacteria and Malassezia decreased from 3.2 ± 0.10 and 3.2 ± 0.11, respectively, to 1.2 ± 0.19 and 1.2 ± 0.24 (p < 0.0001). All the investigated signs further improved at D28. Altogether, these observations suggest that the tested protocol might be useful in managing cAD-associated signs.

Psychometric Testing and Validation of the Italian Version of the Helsinki Chronic Pain Index (I-HCPI) in Dogs with Pain Related to Osteoarthritis.

Pain assessment is of paramount importance for properly managing dogs with osteoarthritis (OA) pain. The aim of the present study was to develop and psychometrically validate the Italian version of the Helsinki Chronic Pain Index (I-HCPI). Owners of OA painful (n = 87) and healthy dogs (n = 40) were administered the I-HCPI once or twice after an eight-week meloxicam treatment. Sixty-nine owners of healthy and OA dogs also completed the Italian version of the Canine Brief Pain Inventory (I-CBPI). Pain on palpation on a 0-4 scale was assessed on all recruited dogs. Construct validity was tested both with hypothesis testing and principal component analysis, confirming the I-HCPI accurately measured chronic pain. Good convergent and criterion validity were shown through correlations with I-CBPI subscores and distribution among pain on palpation scores (p < 0.0001). The significant difference between the pre- and post-treatment I-HCPI scores (p < 0.0001) and Cohen's effect size (2.27) indicated excellent responsiveness. The I-HCPI was shown to be reliable through communalities (range 0.47-0.90) and Cronbach α (≥0.95). Discriminative ability and cut-off point, as tested through Receiver Operating Characteristic analysis, showed excellent diagnostic accuracy with a threshold value of 11 (specificity 0.98 and sensitivity 0.94). The I-HCPI was confirmed to be a valid, sensitive, reliable, and accurate tool to discriminate between dogs with and without pain.

Inhibitory effect of topical adelmidrol on antigen-induced skin wheal and mast cell behavior in a canine model of allergic dermatitis.

BACKGROUND: Adelmidrol is a semisynthetic derivative of azelaic acid and analogue of the anti-inflammatory compound palmitoylethanolamide (PEA). Based upon its physicochemical properties, adelmidrol is suitable for topical application. The main objective of the present study was to evaluate the efficacy of a topical adelmidrol emulsion on early and late inflammatory responses in hypersensitive dogs. Repeated intradermal injections of Ascaris suum extract were performed in both lateral thoracic areas of six conscious hypersensitive Beagle dogs, topically treated during 8 consecutive days. Adelmidrol (2%) was applied to one side and vehicle to the other. 24 hours after the last antigen challenge, two biopsies (adelmidrol- and vehicle-treated side) were obtained for each dog at the antigen injection site. RESULTS: A significant reduction in the antigen-induced wheal areas was observed on the 4th and 7th day of adelmidrol treatment. Moreover, cutaneous mast cell numbers were significantly decreased in biopsies obtained after 8 consecutive days of topical adelmidrol treatment. CONCLUSIONS: The results obtained in the present study show that topical treatment with adelmidrol might represent a new therapeutic tool in controlling the early and late allergic inflammatory skin responses in companion animals.

Initial Psychometric Testing and Validation of the Italian Version of the Canine Brief Pain Inventory in Dogs With Pain Related to Osteoarthritis.

The Canine Brief Pain Inventory (CBPI) is an owner-administered questionnaire, originally developed and validated in English, used to assess canine chronic pain in terms of severity and interference with daily life activities. The aim of the present study was to perform a preliminary validation of an Italian version of the CBPI. Translation was performed and the resulting questionnaire was administered to 45 native Italian speaking owners of dogs suffering from chronic pain due to radiographically confirmed osteoarthritis. Psychometric properties of the Italian CBPI including construct validity, convergent validity and reliability were evaluated. Construct validity was assessed by factor analysis and confirmed a two-factor model (i.e., pain severity and interference factors). The respective scores, that is, the pain severity score (PSS) and pain interference score (PIS), exhibited a substantial negative correlation with overall quality of life score. Pain severity and interference items showed a mean inter-item correlation of 0.90 and 0.80, respectively. For each question, communality ranged from 0.84 to 0.97, highlighting strong internal consistency and suggesting that PSS and PIS can be calculated by averaging the items contained within each factor. Cronbach's α was 0.97 and 0.96 for PSS and PIS, respectively. The present findings confirmed the main psychometric properties of the Italian version of the CBPI, providing clinicians and researchers with a useful metrology instrument to evaluate the severity of chronic pain and its interference with daily life activities in dogs with osteoarthritis owned by Italian speaking people. Further properties of the questionnaire need to be evaluated in future research and larger studies are warranted.

Establishment of a 2-week canine skin organ culture model and its pharmacological modulation by epidermal growth factor and dexamethasone.

Although canine skin models are already available as either monocellular or organotypic cultures, they only partly recapitulate normal skin morphological features and function. The objective of this study was to establish a canine serum-free skin organ culture model and verify whether dexamethasone could rescue epidermal growth factor-induced changes. The study of morphological changes as a response to pharmacological substances may indeed help to investigate skin physiology and pathology. Normal skin was obtained from five client-owned dogs subjected to surgical procedures unrelated to dermatological conditions. Two experimental designs were performed: (i) two-week viability of the skin culture; (ii) dexamethasone (DMS) inhibition of epidermal growth factor (EGF)-induced effects. Serum-free submerged organ cultures were established in Williams' E medium supplemented with penicillin-streptomycin, insulin, hydrocortisone and l-glutamine. General morphological features of skin anatomical structures were well maintained up to day 14, scattered pyknotic nuclei were visible in the epidermis from day 7. Normal keratinocyte differentiation was confirmed by cytokeratin (K) 10, K14 and loricrin immunostaining. Epidermal thickness did not decrease throughout the study. A decrease in keratinocyte proliferation was observed at day 7 and 14. Treatment with EGF induced both keratinocyte proliferation and thickening of the epidermis; both responses were counteracted by DMS. Treatment with EGF increased the length of epithelial tongues at the edge of the skin explants; this effect was further enhanced by DMS supplementation. Our findings demonstrate the potential use of a full-thickness canine skin organ culture model for the study of skin physiology and pharmacological response to exogenous compounds, especially in the field of re-epithelialisation and keratinization disorders.

Effects of palmitoylethanolamide on the cutaneous allergic inflammatory response in Ascaris hypersensitive Beagle dogs.

Palmitoylethanolamide (PEA) is an endogenous lipid mediator with anti-inflammatory and anti-hyperalgesic properties. The main objective of the present study was to evaluate the effects of PEA on the cutaneous allergic inflammatory reaction induced by different immunological and non-immunological stimuli in hypersensitive dogs. Six spontaneously Ascaris hypersensitive Beagle dogs were challenged with intradermal injections of Ascaris suum extract, substance P and anti-canine IgE, before and after a single oral administration of PEA at doses of 3, 10 and 30 mg/kg. A significant reduction in wheal area induced by both antigen and anti-canine IgE challenge was observed after PEA administration. No significant differences were observed between the two higher doses studied, suggesting that the 10 mg/kg dose had exerted the maximum inhibitory effect. When blood levels of PEA were compared with the effects at different times, an evident correlation was obtained. However, the anti-inflammatory effects of PEA were more long-lasting than their plasma concentrations. The intradermal injection of substance P did not reveal any skin reaction (wheal or erythema formation) at any of the concentrations tested. In conclusion, PEA might constitute a new therapeutic strategy for the treatment of allergic inflammatory skin diseases in companion animals.