VTA µ-opioidergic neurons facilitate low sociability in protracted opioid withdrawal.

Opioids initiate dynamic maladaptation in brain reward and affect circuits that occur throughout chronic exposure and withdrawal that persist beyond cessation. Protracted withdrawal is characterized by negative affective behaviors such as heightened anxiety, irritability, dysphoria, and anhedonia, which pose a significant risk factor for relapse. While the ventral tegmental area (VTA) and mu-opioid receptors (MORs) are critical for opioid reinforcement, the specific contributions of VTAMOR neurons in mediating protracted withdrawal-induced negative affect is not fully understood. In our study, we elucidate the role of VTAMOR neurons in mediating negative affect and altered brain-wide neuronal activities following opioid exposure and withdrawal in male and female mice. Utilizing a chronic oral morphine administration model, we observe increased social deficit, anxiety-related, and despair-like behaviors during protracted withdrawal. VTAMOR neurons show heightened neuronal FOS activation at the onset of withdrawal and connect to an array of brain regions that mediate reward and affective processes. Viral re-expression of MORs selectively within the VTA of MOR knockout mice demonstrates that the disrupted social interaction observed during protracted withdrawal is facilitated by this neural population, without affecting other protracted withdrawal behaviors. Lastly, VTAMORs contribute to heightened neuronal FOS activation in the anterior cingulate cortex (ACC) in response to an acute morphine challenge, suggesting their unique role in modulating ACC-specific neuronal activity. These findings identify VTAMOR neurons as critical modulators of low sociability during protracted withdrawal and highlight their potential as a mechanistic target to alleviate negative affective behaviors associated with opioid withdrawal.

Neural Network Connectivity Following Opioid Dependence is Altered by a Common Genetic Variant in the µ-Opioid Receptor, OPRM1 A118G.

Opioid use disorder is a chronic, relapsing disease associated with persistent changes in brain plasticity. A common single nucleotide polymorphism (SNP) in the µ-opioid receptor gene, OPRM1 A118G, is associated with altered vulnerability to opioid addiction. Reconfiguration of neuronal connectivity may explain dependence risk in individuals with this SNP. Mice with the equivalent Oprm1 variant, A112G, demonstrate sex-specific alterations in the rewarding properties of morphine and heroin. To determine whether this SNP influences network-level changes in neuronal activity, we compared FOS expression in male and female mice that were opioid-naive or opioid-dependent. Network analyses identified significant differences between the AA and GG Oprm1 genotypes. Based on several graph theory metrics, including small-world analysis and degree centrality, we show that GG females in the opioid-dependent state exhibit distinct patterns of connectivity compared to other groups of the same genotype. Using a network control theory approach, we identified key cortical brain regions that drive the transition between opioid-naive and opioid-dependent brain states; however, these regions are less influential in GG females leading to sixfold higher average minimum energy needed to transition from the acute to the dependent state. In addition, we found that the opioid-dependent brain state is significantly less stable in GG females compared to other groups. Collectively, our findings demonstrate sex- and genotype-specific modifications in local, mesoscale, and global properties of functional brain networks following opioid exposure and provide a framework for identifying genotype differences in specific brain regions that play a role in opioid dependence.

Point-of-Care Blood Coagulation Assay Based on Dynamic Monitoring of Blood Viscosity Using Droplet Microfluidics.

Monitoring of the coagulation function has applications in many clinical settings. Routine coagulation assays in the clinic are sample-consuming and slow in turnaround. Microfluidics provides the opportunity to develop coagulation assays that are applicable in point-of-care settings, but reported works required bulky sample pumping units or costly data acquisition instruments. In this work, we developed a microfluidic coagulation assay with a simple setup and easy operation. The device continuously generated droplets of blood sample and buffer mixture and reported the temporal development of blood viscosity during coagulation based on the color appearance of the resultant droplets. We characterized the relationship between blood viscosity and color appearance of the droplets and performed experiments to validate the assay results. In addition, we developed a prototype analyzer equipped with simple fluid pumping and economical imaging module and obtained similar assay measurements. This assay showed great potential to be developed into a point-of-care coagulation test with practical impact.

Point-of-care blood coagulation assay enabled by printed circuit board-based digital microfluidics.

The monitoring of coagulation function has great implications in many clinical settings. However, existing coagulation assays are simplex, sample-consuming, and slow in turnaround, making them less suitable for point-of-care testing. In this work, we developed a novel blood coagulation assay that simultaneously assesses both the tendency of clotting and the stiffness of the resultant clot using printed circuit board (PCB)-based digital microfluidics. A drop of blood was actuated to move back and forth on the PCB electrode array, until the motion winded down as the blood coagulated and became thicker. The velocity tracing and the deformation of the clot were calculated via image analysis to reflect the coagulation progression and the clot stiffness, respectively. We investigated the effect of different hardware and biochemical settings on the assay results. To validate the assay, we performed assays on blood samples with hypo- and hyper-coagulability, and the results confirmed the assay's capability in distinguishing different blood samples. We then examined the correlation between the measured metrics in our assays and standard coagulation assays, namely prothrombin time and fibrinogen level, and the high correlation supported the clinical relevance of our assay. We envision that this method would serve as a powerful point-of-care coagulation testing method.

Anaerobic fermentation of peanut meal to produce even-chain volatile fatty acids using Saccharomyces cerevisiae inoculum.

In this study, the effects of inoculating Saccharomyces cerevisiae (S. cerevisiae) on the production of volatile fatty acids (VFAs) via anaerobic fermentation of organic solid waste peanut meal were investigated. At 35°C (temperature of the medium), inoculums consisting of six different S. cerevisiae-peanut meal ratios were used in sequencing batch anaerobic fermentation, and the changes in VFA, protein, glycogen, pH, NH4+, and soluble chemical oxygen demand (SCOD) levels during the fermentation process were studied. Results showed that after inoculation with S. cerevisiae, the anaerobic fermentation of peanut meal mainly produced even-chain VFAs (acetic acid and n-butyric acid); in the early stage of fermentation, inoculation of S. cerevisiae enhanced protein dissolution efficiency and degradation rate, and completely degraded soluble glycogen. The utilization ratio of the protein and soluble glycogen improved. Analysis of significant difference showed that compared to the peanut meal control, the experimental group correlated significantly with the VFAs. The VFA obtained with the inoculum: peanut meal ratio of 0.15 g g-1 was mainly acetic acid, with peak concentration of 10,797.09 mg L-1, which was 1.82 times higher than that obtained with only the peanut meal fermentation. Response surface methodology predicted that the inoculation ratio was 0.15 g g-1, and the effect of producing VFAs was the best when the fermentation time was 8.63d. The results showed that S. cerevisiae inoculation may improve VFA production and increase the proportion of even acids.

Micro-oxygen Process Improved Synthesis of PHAs with Undomesticated Excess Sludge.

Polyhydroxyalkanoates (PHAs) are a potential substitute for traditional plastics. Synthesis of PHAs using excess sludge without additional domestication as a mixed microbial culture can reduce production costs. PHAs were synthesized using excess sludge (R1) from a continuous flow system performing simultaneous nitrification/denitrification and phosphorus removal. Excess sludge (R2) from a A2O wastewater treatment plant was used as a mixed microflora culture (MMC) and the waste fermentation liquid was used as a carbon source. Results showed that with volatile fatty acid (VFA) concentrations of 430-520 mg/L (COD of 650-750 mg/L), when R1 and R2 were reacted under anaerobic conditions, the maximum generated concentrations of PHAs were 84.41 mg/g and 30.8 mg/g, respectively. When aeration volumes were 5, 10, 15, and 20 L/h, the amounts of PHAs synthesized from R1 and R2 increased by varying degrees, with the highest amount generated at 10 L/h (108.6 mg/g and 58.58 mg/g, respectively). In the process of PHA formation, ORP shows a decreasing trend. When the concentration of PHAs reaches a maximum level, ORP drops to a "valley point." Lower ORP valley points indicate a higher potential for synthesis of PHAs. Therefore, ORP can be used as a control parameter to reflect the reaction process in the micro-oxygen synthesis of PHAs.