Mobile Mindfulness Meditation for Cancer-Related Anxiety and Neuropathy: Protocol for a Randomized Controlled Trial.

BACKGROUND: Anxiety- and cancer-related neuropathy are two persistent effects related to treatment for cancer. Mindfulness meditation has been used with substantial impact as a nonpharmacologic intervention to mitigate side and late effects of treatment. Mobile apps are ubiquitous for most of the general population, yet have a particular relevance for cancer survivors, given that physical and geographic limitations can be present. OBJECTIVE: This study aims to describe an ongoing trial of the Mindfulness Coach mobile app for cancer survivors. METHODS: In this randomized waitlist controlled trial, cancer survivors experiencing anxiety- or cancer-related neuropathy (200 for neuropathy and 200 for anxiety) and who had finished primary cancer treatment were invited to participate. Data were collected at 3 time points regardless of randomization condition: baseline, 8 weeks, and 16 weeks. Both face-to-face and web-based recruitment strategies were used. The trial was opened for 2 separate primary outcomes (anxiety- or cancer-related neuropathy). The goal was not to compare these groups but to compare treatment and waitlist groups for each condition. In addition to evaluating the impact of mobile mindfulness on reported anxiety- or cancer-related neuropathy, other pain, fatigue, trauma, sleep, and satisfaction with the Mindfulness Coach app will also be assessed. RESULTS: Outcomes of the study are expected in early 2024. CONCLUSIONS: Mindfulness meditation has become widely practiced, and the use of mobile technology has become ubiquitous. Finding ways to deliver mindfulness meditation to people who have been treated for cancer allows for the intervention to be accessible to a larger number of survivors. The results of this intervention could have implications for further understanding the impact of mindfulness meditation on 2 persistent side and late effects of treatment of cancer, namely anxiety- and cancer-related neuropathy. TRIAL REGISTRATION: ClinicalTrials.gov NCT03581357; https://ClinicalTrials.gov/study/NCT03581357. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/47745.

Recruiting Cancer Survivors to a Mobile Mindfulness Intervention in the United States: Exploring Online and Face-to-Face Recruitment Strategies.

Cancer survivorship research faces several recruitment challenges, such as accrual of a representative sample, as well as participant retention. Our study explores patterns in recruited demographics, patient-reported outcomes (PROs), and retention rates for a randomized controlled trial (RCT) utilizing a mobile mindfulness intervention for the well-being of cancer survivors. In total, 123 participants were recruited using traditional and online strategies. Using the chi-square test of independence, recruitment type was compared with demographic and clinical variables, PROs, and retention at Time 2 and Time 3. Online recruitment resulted in almost double the yield compared to traditional recruitment. Online-recruited participants were more often younger, from the continental U.S., Caucasian, diagnosed and treated less recently, at a later stage of diagnosis, diagnosed with blood cancer, without high blood pressure, and with less reported pain. The recruitment method was not significantly associated with retention. Online recruitment may capture a larger, broader survivor sample, but, similar to traditional recruitment, may also lead to selection biases depending on where efforts are focused. Future research should assess the reasons underlying the higher yield and retention rates of online recruitment and should evaluate how to apply a mix of traditional and online recruitment strategies to efficiently accrue samples that are representative of the survivor population.

Further characterization of the synergistic activation mechanism of cationic channels by M2 and M3 muscarinic receptors in mouse intestinal smooth muscle cells.

In mouse ileal myocytes, muscarinic receptor-mediated cationic current (mIcat) occurs mainly through synergism of M2 and M3 subtypes involving Gi/o-type GTP-binding proteins and phospholipase C (PLC). We have further studied the M2/M3 synergistic pathway. Carbachol-induced mIcat was markedly depressed by YM-254890, a Gq/11 protein inhibitor. However, the mIcat was unaffected by heparin, calphostin C, or chelerythrine, suggesting that mIcat activation does not involve signaling molecules downstream of phosphatidylinositol 4,5-bisphosphate (PIP2) breakdown. M2-knockout (KO) mice displayed a reduced mIcat (~10% of wild-type mIcat) because of the lack of M2-Gi/o signaling. The impaired mIcat was insensitive to neuropeptide Y possessing a Gi/o-stimulating activity. M3-KO mice also displayed a reduced mIcat (~6% of wild-type mIcat) because of the lack of M3-Gq/11 signaling, and the mIcat was insensitive to prostaglandin F2α possessing a Gq/11-stimulating activity. These results suggest the importance of Gq/11/PLC-hydrolyzed PIP2 breakdown itself in mIcat activation and also support the idea that the M2/M3 synergistic pathway represents a signaling complex consisting of M2-Gi/o and M3-Gq/11-PLC systems in which both G proteins are special for this pathway but not general in receptor coupling.

Characterization of muscarinic receptor-mediated cationic currents in longitudinal smooth muscle cells of mouse small intestine.

In mouse intestinal smooth muscle cells held at -50 mV, carbachol evoked an atropine-sensitive inward current in the intracellular presence of Cs(+). The current response consisted of an initial peak followed by a smaller plateau component on which oscillatory currents frequently arose. Results from various experimental procedures indicated that the inward current is a muscarinic receptor-operated cationic current (mI(cat)) sensitive to cytosolic Ca(2+) concentration ([Ca(2+)](i)) and that the initial peak and oscillatory components are contaminated by Ca(2+)-activated Cl(-) currents. Under conditions of [Ca(2+)](i) buffered to 100 nM, the mI(cat) response to cumulative carbachol applications was inhibited competitively by an M(2)-selective antagonist but non-competitively by an M(3)-selective one. Also it was severely reduced by pertussis toxin (PTX) treatment or a phospholipase C (PLC) inhibitor. Comparative analysis of mI(cat) in mouse and guinea-pig intestinal myocytes indicated that the underlying channels resemble between those myocytes in agonist sensitivity, current-voltage relationship, and unitary conductance. The results suggest that in mouse intestinal myocytes, mI(cat) arises mainly via an M(2)/M(3) synergistic mechanism involving PTX-sensitive G-proteins and PLC activity in the absence of current modulation by [Ca(2+)](i) changes, as described for guinea-pig ileal mI(cat). The channels underlying mI(cat) are also indistinguishable in gating properties between both types of myocytes.

M(2) and M(3) muscarinic receptor-mediated contractions in longitudinal smooth muscle of the ileum studied with receptor knockout mice.

Isometric contractile responses to carbachol were studied in ileal longitudinal smooth muscle strips from wild-type mice and mice genetically lacking M(2) or M(3) muscarinic receptors, in order to characterize the mechanisms involved in M(2) and M(3) receptor-mediated contractile responses. Single applications of carbachol (0.1-100 microM) produced concentration-dependent contractions in preparations from M(2)-knockout (KO) and M(3)-KO mice, mediated via M(3) and M(2) receptors, respectively, as judged by the sensitivity of contractile responses to blockade by the M(2)-preferring antagonist methoctramine (300 nM) or the M(3)-preferring antagonist 4-DAMP (30 nM). The M(2)-mediated contractions were mimicked in shape by submaximal stimulation with high K(+) concentrations (up to 35 mM), almost abolished by voltage-dependent Ca(2+) channel (VDCC) antagonists or depolarization with 140 mM K(+) medium, and greatly reduced by pertussis toxin (PTX) treatment. The M(3)-mediated contractions were only partially inhibited by VDCC antagonists or 140 mM K(+)-depolarization medium, and remained unaffected by PTX treatment. The contractions observed during high K(+) depolarization consisted of different components, either sensitive or insensitive to extracellular Ca(2+). The carbachol contractions observed with wild-type preparations consisted of PTX-sensitive and -insensitive components. The PTX-sensitive component was functionally significant only at low carbachol concentrations. The results suggest that the M(2) receptor, through PTX-sensitive mechanisms, induces ileal contractions that depend on voltage-dependent Ca(2+) entry, especially associated with action potential discharge, and that the M(3) receptor, through PTX-insensitive mechanisms, induces contractions that depend on voltage-dependent and -independent Ca(2+) entry and intracellular Ca(2+) release. In intact tissues coexpressing M(2) and M(3) receptors, M(2) receptor activity appears functionally relevant only when fractional receptor occupation is relatively small.