Effectiveness of interventions to address obesity and health risk behaviours among people with severe mental illness in low- and middle-income countries (LMICs): a systematic review and meta analysis

Abstract Introduction People with severe mental illness (SMI) are more likely to have obesity and engage in health risk behaviours than the general population. The aims of this study are (1) evaluate the effectiveness of interventions that focus on body weight, smoking cessation, improving sleeping patterns, and alcohol and illicit substance abuse; (2) Compare the number of interventions addressing body weight and health risk behaviours in low- and middle-income countries (LMICs) v. those reported in published systematic reviews focusing on high-income countries (HICs). Methods Intervention studies published up to December 2020 were identified through a structured search in the following database; OVID MEDLINE (1946–December 2020), EMBASE (1974–December 2020), CINAHL (1975–2020), APA PsychoINFO (1806–2020). Two authors independently selected studies, extracted study characteristics and data and assessed the risk of bias. and risk of bias was assessed using the Cochrane risk of bias tool V2. We conducted a narrative synthesis and, in the studies evaluating the effectiveness of interventions to address body weight, we conducted random-effects meta-analysis of mean differences in weight gain. We did a systematic search of systematic reviews looking at cardiometabolic and health risk behaviours in people with SMI. We compared the number of available studies of LMICs with those of HICs. Results We assessed 15 657 records, of which 9 met the study inclusion criteria. Six focused on healthy weight management, one on sleeping patterns and two tested a physical activity intervention to improve quality of life. Interventions to reduce weight in people with SMI are effective, with a pooled mean difference of −4.2 kg (95% CI −6.25 to −2.18, 9 studies, 459 participants, I2 = 37.8%). The quality and sample size of the studies was not optimal, most were small studies, with inadequate power to evaluate the primary outcome. Only two were assessed as high quality (i.e. scored ‘low’ in the overall risk of bias assessment). We found 5 reviews assessing the effectiveness of interventions to reduce weight, perform physical activity and address smoking in people with SMI. From the five systematic reviews, we identified 84 unique studies, of which only 6 were performed in LMICs. Conclusion Pharmacological and activity-based interventions are effective to maintain and reduce body weight in people with SMI. There was a very limited number of interventions addressing sleep and physical activity and no interventions addressing smoking, alcohol or harmful drug use. There is a need to test the feasibility and cost-effectiveness of context-appropriate interventions to address health risk behaviours that might help reduce the mortality gap in people with SMI in LMICs

Phosphatidylinositol-3 Phosphatase Myotubularin-Related Protein 6 Negatively Regulates CD4 T Cells

Intracellular Ca(2+) levels rapidly rise following cross-linking of the T-cell receptor (TCR) and function as a critical intracellular second messenger in T-cell activation. It has been relatively under appreciated that K(+) channels play an important role in Ca(2+) influx into T lymphocytes by helping to maintain a negative membrane potential which provides an electrochemical gradient to drive Ca(2+) influx. Here we show that the Ca(2+)-activated K(+) channel, KCa3.1, which is critical for Ca(2+) influx in reactivated naive T cells and central memory T cells, requires phosphatidylinositol-3 phosphatase [PI(3)P] for activation and is inhibited by the PI(3)P phosphatase myotubularin-related protein 6 (MTMR6). Moreover, by inhibiting KCa3.1, MTMR6 functions as a negative regulator of Ca(2+) influx and proliferation of reactivated human CD4 T cells. These findings point to a new and unexpected role for PI(3)P and the PI(3)P phosphatase MTMR6 in the regulation of Ca(2+) influx in activated CD4 T cells and suggest that MTMR6 plays a critical role in setting a minimum threshold for a stimulus to activate a T cell

Selective posttranslational inhibition of CaVβ1-associated voltage-dependent calcium channels with a functionalized nanobody

Ca2+ influx through high-voltage-activated calcium channels (HVACCs) controls diverse cellular functions. A critical feature enabling a singular signal, Ca2+ influx, to mediate disparate functions is diversity of HVACC pore-forming α1 and auxiliary CaVβ1-CaVβ4 subunits. Selective CaVα1 blockers have enabled deciphering their unique physiological roles. By contrast, the capacity to post-translationally inhibit HVACCs based on CaVβ isoform is non-existent. Conventional gene knockout/shRNA approaches do not adequately address this deficit owing to subunit reshuffling and partially overlapping functions of CaVβ isoforms. Here, we identify a nanobody (nb.E8) that selectively binds CaVβ1 SH3 domain and inhibits CaVβ1-associated HVACCs by reducing channel surface density, decreasing open probability, and speeding inactivation. Functionalizing nb.E8 with Nedd4L HECT domain yielded Chisel-1 which eliminated current through CaVβ1-reconstituted CaV1/CaV2 and native CaV1.1 channels in skeletal muscle, strongly suppressed depolarization-evoked Ca2+ influx and excitation-transcription coupling in hippocampal neurons, but was inert against CaVβ2-associated CaV1.2 in cardiomyocytes. The results introduce an original method for probing distinctive functions of ion channel auxiliary subunit isoforms, reveal additional dimensions of CaVβ1 signaling in neurons, and describe a genetically-encoded HVACC inhibitor with unique properties

Delta Opioid Receptors Presynaptically Regulate Cutaneous Mechanosensory Neuron Input to the Spinal Cord Dorsal Horn.

SummaryCutaneous mechanosensory neurons detect mechanical stimuli that generate touch and pain sensation. Although opioids are generally associated only with the control of pain, here we report that the opioid system in fact broadly regulates cutaneous mechanosensation, including touch. This function is predominantly subserved by the delta opioid receptor (DOR), which is expressed by myelinated mechanoreceptors that form Meissner corpuscles, Merkel cell-neurite complexes, and circumferential hair follicle endings. These afferents also include a small population of CGRP-expressing myelinated nociceptors that we now identify as the somatosensory neurons that coexpress mu and delta opioid receptors. We further demonstrate that DOR activation at the central terminals of myelinated mechanoreceptors depresses synaptic input to the spinal dorsal horn, via the inhibition of voltage-gated calcium channels. Collectively our results uncover a molecular mechanism by which opioids modulate cutaneous mechanosensation and provide a rationale for targeting DOR to alleviate injury-induced mechanical hypersensitivity

Article Delta Opioid Receptors Presynaptically Regulate Cutaneous Mechanosensory Neuron Input to the Spinal Cord Dorsal Horn

International audienceCutaneous mechanosensory neurons detect mechanical stimuli that generate touch and pain sensation. Although opioids are generally associated only with the control of pain, here we report that the opioid system in fact broadly regulates cutaneous mecha-nosensation, including touch. This function is predominantly subserved by the delta opioid receptor (DOR), which is expressed by myelinated mecha-noreceptors that form Meissner corpuscles, Merkel cell-neurite complexes, and circumferential hair follicle endings. These afferents also include a small population of CGRP-expressing myelinated noci-ceptors that we now identify as the somatosensory neurons that coexpress mu and delta opioid receptors. We further demonstrate that DOR activation at the central terminals of myelinated mechanorecep-tors depresses synaptic input to the spinal dorsal horn, via the inhibition of voltage-gated calcium channels. Collectively our results uncover a molecular mechanism by which opioids modulate cuta-neous mechanosensation and provide a rationale for targeting DOR to alleviate injury-induced mechanical hypersensitivity