Respiratory depression and somnolence in children receiving dimethylsulfoxide and morphine during hematopoietic stem cells transplantation

Endocannabinoid agonist 2-arachidonoylglycerol differentially alters diurnal activity and sleep during fentanyl withdrawal in male and female mice

Fentanyl has become the leading driver of opioid overdoses in the United States. Cessation of opioid use represents a challenge as the experience of withdrawal drives subsequent relapse. One of the most prominent withdrawal symptoms that can contribute to opioid craving and vulnerability to relapse is sleep disruption. The endocannabinoid agonist, 2-Arachidonoylglycerol (2-AG), may promote sleep and reduce withdrawal severity; however, the effects of 2-AG on sleep disruption during opioid withdrawal have yet to be assessed. Here, we investigated the effects of 2-AG administration on sleep-wake behavior and diurnal activity in mice during withdrawal from fentanyl. Sleep-wake activity measured via actigraphy was continuously recorded before and after chronic fentanyl administration in both male and female C57BL/6 J mice. Immediately following cessation of fentanyl administration, 2-AG was administered intraperitoneally to investigate the impact of endocannabinoid agonism on opioid-induced sleep disruption. We found that female mice maintained higher activity levels in response to chronic fentanyl than male mice. Furthermore, fentanyl administration increased wake and decreased sleep during the light period and inversely increased sleep and decreased wake in the dark period in both sexes. 2-AG treatment increased arousal and decreased sleep in both sexes during first 24-h of withdrawal. On withdrawal day 2, only females showed increased wakefulness with no changes in males, but by withdrawal day 3 male mice displayed decreased rapid-eye movement sleep during the dark period with no changes in female mice. Overall, repeated administration of fentanyl altered sleep and diurnal activity and administration of the endocannabinoid agonist, 2-AG, had sex-specific effects on fentanyl-induced sleep and diurnal changes.

Sex-specific Effects of the Endocannabinoid Agonist 2-Arachidonoylglycerol on Sleep and Circadian Disruptions during Fentanyl Withdrawal

Fentanyl has become the leading driver of opioid overdoses. Cessation of opioid use represents a challenge as the experience of withdrawal drives subsequent relapse. One of the most prominent withdrawal symptoms that can contribute to opioid craving and vulnerability to relapse is sleep disruption. The endocannabinoid agonist, 2-Arachidonoylglycerol (2-AG), may promote sleep and reduce withdrawal severity; however, the effects of 2-AG on sleep disruption during opioid withdrawal have yet to be assessed. Here, we investigate the effects of 2-AG administration on sleep-wake behavior and diurnal activity in mice during withdrawal from fentanyl. Sleep-wake activity was continuously recorded before and after chronic fentanyl administration in both male and female C57BL/6J mice. Immediately following cessation of fentanyl administration, 2-AG was administered intraperitoneally to investigate the impact of endocannabinoid agonism on opioid-induced sleep disruption. Female mice maintained higher activity levels in response to chronic fentanyl than male mice. Furthermore, fentanyl increased wake and decreased sleep during the light period and inversely increased sleep and decreased wake in the dark period in both sexes. 2-AG treatment increased arousal and decreased sleep in both sexes during first 24 hrs of withdrawal. On withdrawal day 2, only female showed increased wakefulness with no changes in males, but by withdrawal day 3 male mice displayed decreased rapid-eye movement sleep during the dark period with no changes in female mice. Overall, repeated administration of fentanyl altered sleep and diurnal activity and administration of the endocannabinoid agonist, 2-AG, had sex-specific effects on fentanyl-induced sleep and diurnal changes.

Thermal Sensitivity and Dimethyl Sulfoxide (DMSO)

Dimethyl sulfoxide (DMSO) is commonly used as a solvent for hydrophobic substances, but the compound's innate bioactivity is an area of limited understanding. In this investigation we seek to determine the analgesic potential of DMSO. We addressed the issue by assessing the perception of thermal pain stimulus, using a 55 °C hotplate design, in conscious mice. The latency of withdrawal behaviors over a range of incremental accumulative intraperitoneal DMSO doses (0.5-15.5 g/kg) in the same mouse was taken as a measure of thermal endurance. The findings were that the latency, on average, amounted to 15-30 s and it differed inappreciably between the sequential DMSO conditions. Nor was it different from the pre-DMSO control conditions. Thus, DMSO did not influence the cutaneous thermal pain perception. The findings do not lend support to those literature reports that point to the plausible antinociceptive potential of DMSO as one of a plethora of its innate bioactivities. However, the findings concern the mouse's footpad nociceptors which have specific morphology and stimulus transduction pathways, which cannot exclude DMSO's antinociceptive influence on other types of pain or in other types of skin. Complex and as yet unresolved neural mechanisms of perception of cutaneous noxious heat stimulus should be further explored with alternative experimental designs.

Successful Consecutive Expansion of Limbal Explants Using a Biosafe Culture Medium under Feeder Layer-Free Conditions

PURPOSE

Transplantation of in vitro cultured limbal epithelial stem cells (LESCs) is a treatment widely used for LESC deficiency. However, the number of limbal tissue donors is limited, and protocols for LESC cultivation often include compounds and/or feeder layers that can induce side effects and/or increase the cost of the culture procedure. We investigated the feasibility of obtaining more than one limbal primary culture (LPC) from the same biopsy using a culture medium in which several potentially harmful compounds were replaced at the same time by biosafe supplements, allowing the LESC cultivation without feeder layers.

MATERIALS AND METHODS

We established feeder layer-free LPCs with three culture media: (1) a modified supplemental hormonal epithelial medium, containing potential harmful components (cholera toxin, dimethylsulfoxide, and fetal bovine serum [FBS]), (2) IOBA-FBS, a medium with FBS but with no other harmful supplements, and (3) IOBA-HS, similar to IOBA-FBS but with human serum instead of FBS. Additionally, the same limbal explant was consecutively cultured with IOBA-HS producing three cultures. LPCs were characterized by real-time reverse transcription polymerase chain reaction and/or immunofluorescence.

RESULTS

LPCs cultured with the three media under feeder layer-free conditions showed cuboidal cells and no significant differences in the percentage of positive cells for limbal (ABCG2, p63, and K14) and corneal (K3, K12) proteins. Except for ABCG2, the relative mRNA expression of the LESC markers was significantly higher when IOBA-FBS or IOBA-HS was used. LPC1 showed characteristics similar to LPC0, while LPC2 cell morphology became elongated and the expression of some LESC markers was diminished.

CONCLUSION

IOBA-HS enables the culturing of up to two biosafe homologous LPCs from one limbal tissue under feeder layer-free conditions. The routine use of this culture medium could improve both the biosafety and the number of available LPCs for potential clinical transplantation, as well as decrease the expense of the culture procedure.

Morphine modulates doxorubicin uptake and improves efficacy of chemotherapy in an intracranial xenograft model of human glioblastoma

Morphine may alter the permeability of Blood-Brain Barrier (BBB), enhancing the access of molecules normally unable to cross it, as Doxorubicin (Dox). In addition, morphine seems to mediate the uptake of Dox into the brain by its reduced efflux mediated by P-glycoprotein (P-gp). We evaluated the antitumor efficacy of Dox plus morphine treatment by an orthotopic glioblastoma xenograft model. Foxn1 mice were injected with U87MG-luc cells in the left lobe of the brain and treated with Dox (5 mg/kg and 2.5 mg/kg, weekly) with or without morphine pretreatment (10 mg/kg, weekly). Bioluminescence imaging (BLI) was used to monitoring tumor growth and response to therapy. Additionally, we investigated the role of morphine on the uptake of Dox by MDCKII cells transfected with human MDR1 gene encoding for P-gp. The data demonstrate that only Dox 5 mg/kg determined a significant tumor regression while the lower dose (2.5 mg/kg) was not effective. However, if combined with morphine, the group treated with Dox 2.5 mg/kg showed a decreasing tumor growth. The average BLI for Dox 2.5 mg/kg plus morphine was 5 fold lower than Dox 2.5 mg/kg alone (P=0.0053) and 8 fold lower than vehicle (P=0.0004). Additionally, Dox increased in MDCKII-P-gp transfected cells only in the presence of morphine with a significantly higher level comparing control group (3.84) vs Dox plus morphine group (12.29, P<0.05). Our results indicate that Dox alone and in combination with morphine appear to be effective in controlling the growth of glioblastoma in a xenograft mouse model.

Detection of doxorubicin hydrochloride accumulation in the rat brain after morphine treatment by mass spectrometry

PURPOSE

The blood-brain barrier discriminates the access of several molecules to the brain. This hampers the use of some drugs, as doxorubicin, potentially active for treatment of brain tumors. We explored the feasibility of active modification of the blood-brain barrier protection, by using morphine pretreatment, to allow doxorubicin accumulation in the brain in an animal model.

METHODS

Rats were pretreated with different doses of intraperitoneal morphine before injection of doxorubicin (12 mg/kg). Quantitative analysis of doxorubicin was performed by mass spectrometry. Acute heart and kidney damage was analyzed by measuring doxorubicin accumulation, LDH activity and malondialdehyde plasma levels.

RESULTS

The concentration of doxorubicin was significantly higher in all brain areas of rats pretreated with morphine than in control tissues (P < 0.001). This was evident only at therapeutic morphine dose (10 mg/kg, three times over 24 h), while lower doses (2.5 and 5 mg/kg) were not associated with doxorubicin accumulation. Pretreatment with morphine did not induce an elevation of LDH activity or of lipid peroxidation compared to controls.

CONCLUSION

Our data suggest that morphine pretreatment is able to allow doxorubicin penetration inside the brain, by modulating the blood-brain barrier. This is not associated with acute cardiac or renal toxicity. These preliminary results will enable us to generate novel therapeutic approaches to refractory or recurrent brain tumors, and might be useful in other human diseases of the central nervous system in which molecules usually stopped by the blood-brain barrier may have a therapeutic impact.