Mechanisms involved in the antinociceptive and anti-inflammatory effects of xanthotoxin.

Xanthotoxin (XAT) is a natural furanocoumarin clinically used in the treatment of skin diseases such as vitiligo and psoriasis. Recent studies have also investigated its effects on anti-inflammatory, anti-cognitive dysfunction, and anti-amnesia as a guideline for clinic application. However, little is known about its effects on pain relief. Here, we tested the analgesic effects of XAT in serious acute pain and chronic pain models. For acute pain, we used hot-, capsaicin- and formalin-induced paw licking. Nociceptive threshold was measured by mechanical stimuli with von Frey filaments. For chronic pain, we injected complete Freund's adjuvant (CFA) into the mice's plantar surface of the hind paw to induce inflammatory pain. Heat and mechanical hyperalgesia were evaluated by radiant heat and von Frey filament tests, respectively. To investigate the mechanisms underlying the analgesic effect of XAT, we used calcium imaging and western blot to assess transient receptor potential vanilloid 1 (TRPV1) activity and expression in isolated L4-L6 dorsal root ganglion (DRG) neurons. Haematoxylin and eosin (HE) staining, reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and enzyme-linked immunosorbent assay (ELISA) were used to examine immune cell recruitment and proinflammatory factor release from skin tissue from paw injection sites. Our results demonstrated that XAT not only reduced acute pain behaviors generated by hot, capsaicin, and formalin but also attenuated CFA-induced heat and mechanical hyperalgesia. The analgesic activity of XAT may be achieved by controlling peripheral inflammation, lowering immune cell infiltration at the site of inflammatory tissue, reducing inflammatory factor production, and therefore inhibiting TRPV1 channel sensitization and expression.

Few X-ray and PUVA treatments accelerate photocarcinogenesis in hairless mice.

PUVA is a treatment that combines oral methoxypsoralen (8-MOP) with ultraviolet radiation A (UVA). It is used for severe psoriasis and the early stages of T-cell lymphoma. X-rays are an effective treatment for skin cancers. Both treatments are in higher doses used to treat skin malignancies and simultaneously increase the risk of keratinocyte cancer. The main objective of this study was to test whether a few PUVA or X-ray treatments could delay the development of ultraviolet radiation (UVR)-induced skin tumors in a well-established hairless mouse model. Three groups of immunocompetent mice (total, N = 75) were included in the study. All groups were UVR-exposed during the study period. In addition, one group was treated with PUVA and another group was treated with X-rays at days 45, 52, 90 and 97. A control group was treated with UVR only. We recorded when the first, second and third skin tumors were induced in each mouse. Skin tumors developed significantly earlier in both the PUVA and X-ray groups (median, 188 days) than in the control mice (median, 215 days; p < 0.001). Therefore, a few X-ray and PUVA treatments both significantly accelerated the development of skin tumors in hairless mice, compared to UVR controls. Neither treatment showed a delay of UVR-induced skin tumors and caution should be exercised before applying these treatments to sun-damaged skin.

Assessment of phototoxicity in pigmented Long-Evans rat: sparfloxacin and 8-methoxypsoralen.

The aim of the present work was to evaluate the effects of photo-activated toxicity induced after administration of two known melanin-binding phototoxic compounds, sparfloxacin (SPX) and 8-methoxypsoralen (8-MOP), followed or not by UVA/Vis exposure, in pigmented rats (Long Evans: LE) and albino rats (Sprague Dawley: SD). Groups of three rats were treated with SPX or 8-MOP by oral gavage for six consecutive days. Irradiated animals were submitted to a UVA/Vis light dose standardized to 10 J/cm2 UVA daily. Clinical signs, cutaneous reactions and body weight were monitored throughout the study period. Ear biopsy weight, lymph node weight and lymph node cell count were determined at necropsy. Ophthalmologic examinations were performed before the first treatment and on the day of sacrifice. Microscopic examinations were performed on skin biopsies and eyes. Phototoxicity was demonstrated for both SPX and 8-MOP in the pigmented and albino strains, in terms of auricular irritation, lymph node weight and proliferation index, cutaneous reactions and ocular histopathology. LE rats were less sensitive than SD rats, especially at the ocular level, supporting the notion that pigmentation may provide protection against photo-activation. The pigmented rat may be a more relevant model than the albino rat for human safety evaluation.

Non-steroidal anti-inflammatory drugs (NSAIDs) for chronic non-cancer pain in children and adolescents.

BACKGROUND: Pain is a common feature of childhood and adolescence around the world, and for many young people, that pain is chronic. The World Health Organization guidelines for pharmacological treatments for children's persisting pain acknowledge that pain in children is a major public health concern of high significance in most parts of the world. While in the past pain was largely dismissed and was frequently left untreated, views on children's pain have changed over time, and relief of pain is now seen as important.We designed a suite of seven reviews on chronic non-cancer pain and cancer pain (looking at antidepressants, antiepileptic drugs, non-steroidal anti-inflammatory drugs, opioids, and paracetamol) in order to review the evidence for children's pain utilising pharmacological interventions.As the leading cause of morbidity in the world today, chronic disease (and its associated pain) is a major health concern. Chronic pain (that is pain lasting three months or longer) can arise in the paediatric population in a variety of pathophysiological classifications (nociceptive, neuropathic, or idiopathic) from genetic conditions, nerve damage pain, chronic musculoskeletal pain, and chronic abdominal pain, as well as for other unknown reasons.Non-steroidal anti-inflammatory drugs (NSAIDs) are used to treat pain, reduce fever, and for their anti-inflammation properties. They are commonly used within paediatric pain management. Non-steroidal anti-inflammatory drugs are currently licensed for use in Western countries, however they are not approved for infants under three months old. The main adverse effects include renal impairment and gastrointestinal issues. Common side effects in children include diarrhoea, headache, nausea, constipation, rash, dizziness, and abdominal pain. OBJECTIVES: To assess the analgesic efficacy and adverse events of NSAIDs used to treat chronic non-cancer pain in children and adolescents aged between birth and 17 years, in any setting. SEARCH METHODS: We searched the Cochrane Central Register of Controlled Trials (CENTRAL) via the Cochrane Register of Studies Online, MEDLINE via Ovid, and Embase via Ovid from inception to 6 September 2016. We also searched the reference lists of retrieved studies and reviews, as well as online clinical trial registries. SELECTION CRITERIA: Randomised controlled trials, with or without blinding, of any dose and any route, treating chronic non-cancer pain in children and adolescents, comparing any NSAID with placebo or an active comparator. DATA COLLECTION AND ANALYSIS: Two review authors independently assessed studies for eligibility. We planned to use dichotomous data to calculate risk ratio and number needed to treat for one additional event, using standard methods. We assessed GRADE and created three 'Summary of findings' tables. MAIN RESULTS: We included seven studies with a total of 1074 participants (aged 2 to 18 years) with chronic juvenile polyarthritis or chronic juvenile rheumatoid arthritis. All seven studies compared an NSAID with an active comparator. None of the studies were placebo controlled. No two studies investigated the same type of NSAID compared with another. We were unable to perform a meta-analysis.Risk of bias varied. For randomisation and allocation concealment, one study was low risk and six studies were unclear risk. For blinding of participants and personnel, three studies were low risk and four studies were unclear to high risk. For blinding of outcome assessors, all studies were unclear risk. For attrition, four studies were low risk and three studies were unclear risk. For selective reporting, four studies were low risk, two studies were unclear risk, and one study was high risk. For size, three studies were unclear risk and four studies were high risk. For other potential sources of bias, seven studies were low risk. Primary outcomesThree studies reported participant-reported pain relief of 30% or greater, showing no statistically significant difference in pain scores between meloxicam and naproxen, celecoxib and naproxen, or rofecoxib and naproxen (P > 0.05) (low-quality evidence).One study reported participant-reported pain relief of 50% or greater, showing no statistically significant difference in pain scores between low-dose meloxicam (0.125 mg/kg) and high-dose meloxicam (0.25 mg/kg) when compared to naproxen 10 mg/kg (P > 0.05) (low-quality evidence).One study reported Patient Global Impression of Change, showing 'very much improved' in 85% of ibuprofen and 90% of aspirin participants (low-quality evidence). Secondary outcomesAll seven studies reported adverse events. Participants reporting an adverse event (one or more per person) by drug were: aspirin 85/202; fenoprofen 28/49; ibuprofen 40/45; indomethacin 9/30; ketoprofen 9/30; meloxicam 18/47; naproxen 44/202; and rofecoxib 47/209 (very low-quality evidence).All seven studies reported withdrawals due to adverse events. Participants withdrawn due to an adverse event by drug were: aspirin 16/120; celecoxib 10/159; fenoprofen 0/49; ibuprofen 0/45; indomethacin 0/30; ketoprofen 0/30; meloxicam 10/147; naproxen 17/285; and rofecoxib 3/209 (very low-quality evidence).All seven studies reported serious adverse events. Participants experiencing a serious adverse event by drug were: aspirin 13/120; celecoxib 5/159; fenoprofen 0/79; ketoprofen 0/30; ibuprofen 4/45; indomethacin 0/30; meloxicam 11/147; naproxen 10/285; and rofecoxib 0/209 (very low-quality evidence).There were few or no data for our remaining secondary outcomes: Carer Global Impression of Change; requirement for rescue analgesia; sleep duration and quality; acceptability of treatment; physical functioning as defined by validated scales; and quality of life as defined by validated scales (very low-quality evidence).We rated the overall quality of the evidence (GRADE rating) for our primary and secondary outcomes as very low because there were limited data from studies and no opportunity for a meta-analysis. AUTHORS' CONCLUSIONS: We identified only a small number of studies, with insufficient data for analysis.As we could undertake no meta-analysis, we are unable to comment about efficacy or harm from the use of NSAIDs to treat chronic non-cancer pain in children and adolescents. Similarly, we cannot comment on our remaining secondary outcomes: Carer Global Impression of Change; requirement for rescue analgesia; sleep duration and quality; acceptability of treatment; physical functioning; and quality of life.We know from adult randomised controlled trials that some NSAIDs, such as ibuprofen, naproxen, and aspirin, can be effective in certain chronic pain conditions.

Extracorporeal photopheresis as an immunomodulatory agent: Haematocrit-dependent effects on natural killer cells.

The GvHD is a major cause of morbidity and mortality after allogeneic hematopoietic stem cell transplantation (HSCT). Extracorporeal photopheresis (ECP) represents an alternative therapeutic strategy to immunosuppressive therapy. Although ECP is used since 1990s, the mechanism of action has not yet been completely clarified. We analyzed cells collected from 20 ECP procedures of 4 patients affected by chronic GvHD and, for comparison, Peripheral Blood Mononuclear Cells (PBMCs) of 10 healthy donors undergoing from same type of photochemiotherapy, evaluating by flow cytometry, the effects before and after photoactivation with 8-MOP. The analysis showed a significant increase in cell death after ECP in particular in CD4 T lymphocytes as described in literature correlated with haematocrit value. Most interesting data emerge from the analysis of cytotoxic activity of NK cells, using flow cytometry analysis of surface expression of CD107a in the presence of target cells (K562). In all analyzed samples it was possible to document a statistically significant reduction of the cytotoxic activity of NK cells after photoactivation. The decrease of the cytotoxic activity was related to hematocrit value of leukoapheresis: in fact, lower HCT values were associated with a more marked reduction of cytotoxic activity. The study confirms literature data about the increase of cellular mortality induce by ECP. Furthermore, for the first time it is demonstrated that the ECP exerts a marked and significant inhibitory effect on the cytotoxic activity of NK cells. Our study suggests that lower values of hematocrit are associated with better treatment outcome.

Erythema action spectrum of topical 8-methoxypsoralen-sensitized skin re-evaluated: implications for routine clinical practice.

BACKGROUND: Published methodology used to determine psoralen plus ultraviolet A (PUVA) erythemal action spectrum does not reflect current clinical practice for psoralen sensitization. We re-evaluated the PUVA action spectrum using aqueous 8-methoxypsoralen (8-MOP) 2·6 mg L(-1) as used routinely in current clinical practice. OBJECTIVES: To determine the UVA erythema action spectrum of topical 8-MOP-sensitized normal skin. METHODS: Twenty healthy volunteers with skin phototypes I-V were recruited. Forearms were psoralen-sensitized at 37 °C for 10 min. Six UVA irradiations at 10-nm intervals between 325 and 375 nm were randomly allocated to forearm sites and were applied using a 10-nm bandwidth irradiation monochromator. The visual minimal phototoxic dose (MPD) was recorded on each site at 96 h. RESULTS: Volunteer Boston phototypes were: I, n = 2; II, n = 6; III, n = 6; IV, n = 5 and V, n = 1. The mean MPD (J cm(-2) ) for all subjects at each wavelength was as follows: 325 nm, 0·64 (SD 0·37); 335 nm, 0·80 (SD 0·58); 345 nm, 0·96 (SD 0·55); 355 nm, 1·50 (SD 0·85); 365 nm, 2·19 (SD 0·90); and 375 nm, 2·89 (SD 1·06). Therefore, the relative sensitization at each wavelength (erythemal action spectrum) was: 1, 0·83, 0·67, 0·43, 0·29 and 0·22. There were significant differences between the PUVA erythemal effectiveness at different wavelengths but none between skin types. CONCLUSIONS: This study has established the erythemal action spectrum for bath/soak PUVA therapy as is currently performed. In all volunteers, the peak sensitivity was at 325 nm. All volunteers showed a similar trend across the wavelengths studied irrespective of skin type. The determination of the action spectrum for PUVA-induced erythema is important as it permits reliable estimates of erythemal efficacy of any UVA source where the emission spectrum of the lamp is known or can be measured.

Efficacy and safety of bexarotene combined with psoralen-ultraviolet A (PUVA) compared with PUVA treatment alone in stage IB-IIA mycosis fungoides: final results from the EORTC Cutaneous Lymphoma Task Force phase III randomized clinical trial (NCT00056056).

BACKGROUND: Psoralen plus ultraviolet A (PUVA) is the standard treatment for early stages of mycosis fungoides. There have been no adequate randomized controlled trials with sufficient power comparing this modality with other therapies. OBJECTIVE: To assess disease response and to compare the response rates of patients treated with PUVA alone or PUVA and bexarotene. METHODS: EORTC 21011 (NCT 00056056) was a randomized phase III study comparing combined bexarotene (Targretin(®) ) and PUVA vs. PUVA alone in patients with stage IB and IIA mycosis fungoides (MF). The primary endpoint was the overall response rate [complete clinical response (CCR) plus partial response (PR)]. RESULTS: The study was prematurely closed due to low accrual after 93 of 145 required patients (65%) were randomized. Of the 93 randomized patients, 87 started treatment, 41 received PUVA and 46 received PUVA + bexarotene. Total UVA doses received were 107 J cm(-2) (range 1·4-489·9) in the PUVA arm vs. 101·7 J cm(-2) (0·2-529·9) in the combination arm. The safety profile was acceptable with few grade 3-4 toxicities observed in either arm. More drop-outs due to toxicity were observed in the combination arm compared with the PUVA-alone arm. The best overall response (CCR + PR) rate was 71% for PUVA alone and 77% for the combination arm (P = 0·57). The median duration of response was 9·7 months for PUVA vs. 5·8 months for the combination arm (P = 0·33). CCR was seen in 25 patients of whom 10 received PUVA alone (CCR 22%) and 15 received combination therapy (CCR 31%) (P = 0·45). CCR was sustained in 25% of patients regardless of therapy. There was a trend towards fewer PUVA sessions needed to achieve CCR in the combination arm (median 22) compared with the PUVA arm (median 27·5) (P = 0·11). Similarly, a trend towards lower UVA dose required to achieve CCR in the combination arm (median 55·8 J cm(-2) ) compared with the PUVA arm alone (median 117·5 J cm(-2) ) (P = 0·5) was observed. CONCLUSIONS: No significant difference in response rate or response duration was observed in this study. However, there was a trend towards fewer PUVA sessions and lower UVA dose required to achieve CCR in the combination arm (PUVA + bexarotene) but this did not achieve statistical significance due to insufficient power.

Miniature swine model of phototoxicity testing.

BACKGROUND/PURPOSE: This study determined the threshold doses for 'solar erythema' and for phototoxic responses to 8-methoxypsoralen (8-MOP) in white skin Hanford and grey skin Yucatan miniature swine. METHODS: For threshold erythema determinations, the UVR exposures included both UVA (315-400 nm) and UVB (290-315 nm) radiation by positioning one fluorescent 'sunlamp' among 10 'PUVA' lamps. With this configuration the UVR exposures ranged from 0.5-2.8 times the 'instrumental MED' (MEDi) for Hanford and from 1.0-5.6 times the MEDi for Yucatan. For phototoxicity determinations (i.e., with and without topically-applied graduated concentrations of 8-MOP), the UVB component was minimized by extinguishing the sunlamp, thus permitting higher UVA exposures. RESULTS: The Hanford had the lower UV erythema dose threshold (1.0-1.4 times the MEDi) and the erythema that developed was readily observable. The exposure doses for the phototoxicity test were 5 J/cm(2) of UVA in 35 minutes or 10 J/cm(2) in 70 minutes. The phototoxic (vascular) response to 8-MOP was observed in the two highest concentrations (0.01% and 0.1%) in Hanford pigs, in a dose-related manner. Microscopic evidence of a dose-related response was also observed as the concentration of 8-MOP increased. CONCLUSION: This verified that the Hanford miniature swine is the preferable strain for phototoxic effects. In contrast, UVR exposure of the Yucatan pig skin produced tanning rather than erythema, confirming that the Yucatan is the more appropriate strain for studying the melanization response. Thus, Hanford and Yucatan miniature swine have cutaneous photobiological responses that reflect their respective strain differences.