Objectives: This study examined the plasma concentration of pro-inflammatory cytokine, interleukin 6 (IL-6), and anti-inflammatory cytokine, interleukin 10 (IL-10), in short-, and long-term opioid users with noncancer pain.
Materials and Methods: Adult patients with opioid therapy for noncancer pain were recruited from pain clinics at two tertiary hospital settings in Malaysia between February 2016 and March 2017. They were stratified into short- or long-term users based on opioid prescriptions ≥ 90 days per year. A 10mL blood sample was taken for the analysis of plasma concentrations of IL-6 and IL-10 and were quantified using a highly sensitive multiplex assay.
Results: Of 38 patients recruited, 24% (n = 9/38) and 76% (n = 29/38) were respectively short- and long-term opioid users. Short-term use of opioid was associated with higher levels of IL-6 (mean ± SD, 173.9 ± 13.7 pg/mL) and IL-10 (50 ± 5.8 pg/mL), whereas long-term use of opioids was associated with lower levels (no significant difference) of both cytokines IL6 (125 ± 16.1 pg/mL) and IL10 (41.3 ± 6.7 pg/mL). There was strong correlation between IL-6 and IL-10 within the same group (r² = 0.72, P < 0.05) and (r² = 0.76, P < 0.05) for short- and long-term users, respectively.
Conclusion: The duration of opioid use may modulate the level of pro-inflammatory cytokines in which it was higher in short-term use and lower in long-term use, but the effect of pain relief was similar as both cytokines were well correlated.
METHODS: Study samples were collected from 22 participants; 9 from patients with AKU, 9 from individuals who were AKU carriers, and 4 people served as control. Confirmation of AKU diagnosis was established by the ferric chloride test and quantitative determination of urinary homogentisic acid (HGA) levels.
RESULTS: In the ferric chloride test, the urine samples of AKU patients showed a characteristic black ring upon addition of few drops of ferric chloride solution. During urinary HGA determination, patients with AKU had increased levels of urinary HGA as compared to carriers and controls. The following 10 bacterial species were isolated from the urinary tract of AKU patients, carriers and controls: Sphingomonas paucimobilis, Escherichia coli, Francisella tularensis, Staphylococcus hominis, Staphylococcus haemolyticus, Leuconostoc mesenteroides, Dermacoccus nishinomiyaensis, Kytococcus sedentarius, Serratia fonticola and Granulicatella adiacens. The presence of S. paucimobilis was found in three male patients, and one female each from the carrier and control groups. Almost all study samples were positive for D. nishinomiyaensis and K. sedentarius. S. fonticola and G. adiacens were found only in AKU carrier females.
CONCLUSIONS: The results deduced that males show symptoms of arthritis early and more severely than females and by this it appears that there is an association between these symptoms and the percentage of bacterial infection in males that requires more accurate diagnosis and treatment to clarify such relationship. In the current study, males (patients, carriers, and controls) were more likely to have bacterial infections than females (64% vs. 36%). The 16 and 2 bacterial isolates, detected in 7 males and 2 females AKU patients, respectively, revealed that male AKU patients had a 2.3-fold greater rate of bacterial infection than female AKU patients. Therefore, further studies are warranted to investigate if there's any relationship between higher incidence of bacterial infections and development of AKU-related clinical symptoms in the male population.