Human laboratory models of reward in substance use disorder.

Human laboratory models in substance use disorder provide a key intermediary step between highly controlled and mechanistically informative non-human preclinical methods and clinical trials conducted in human populations. Much like preclinical models, the variety of human laboratory methods provide insights into specific features of substance use disorder rather than modelling the diverse causes and consequences simultaneously in a single model. This narrative review provides a discussion of popular models of reward used in human laboratory research on substance use disorder with a focus on the specific contributions that each model has towards informing clinical outcomes (forward translation) and analogs within preclinical models (backward translation). Four core areas of human laboratory research are discussed: drug self-administration, subjective effects, behavioral economics, and cognitive and executive function. Discussion of common measures and models used, the features of substance use disorder that these methods are purported to evaluate, unique issues for measure validity and application, and translational links to preclinical models and special considerations for studies wishing to evaluate homology across species is provided.

Effects of exercise or metformin on myokine concentrations in patients with breast and colorectal cancer: A phase II multi-centre factorial randomized trial.

BACKGROUND: Physical activity and metformin pharmacotherapy are associated with improved clinical outcomes in breast and colorectal cancer survivors. Myokines are cytokines secreted from skeletal muscle that may mediate these associations. METHODS: This hypothesis-generating analysis used biospecimens collected from a multi-centre 2 × 2 factorial randomized design of 116 patients with stage I-III breast and colorectal cancer who were randomized to 12 weeks of (1) aerobic exercise (moderate intensity titrated to 220 min/week); (2) metformin (850 mg daily for 2 weeks and then titrated to 850 mg twice per day); (3) aerobic exercise and metformin; or (4) control. Fourteen myokines were quantified using a multiplex panel. Myokine concentrations were log-transformed, and main effects analyses were conducted using linear mixed-effects regression models. The type I error rate was controlled with the Holm sequential testing procedure. RESULTS: Randomization to exercise increased leukaemia inhibitory factor (1.26 pg/mL, 95% confidence interval [CI]: 0.69, 1.84; adjusted P = 0.001) and interleukin-15 (2.23 pg/mL, 95% CI: 0.87, 3.60; adjusted P = 0.013) compared with randomization to no exercise. Randomization to metformin decreased apelin (-2.69 pg/mL, 95% CI: -4.31, -1.07; adjusted P = 0.014) and interleukin-15 (-1.74 pg/mL, 95% CI: -2.79, -0.69; adjusted P = 0.013) compared with randomization to no metformin. Metformin decreased myostatin, irisin, oncostatin M, fibroblast growth factor 21 and osteocrin; however, these changes were not statistically significant after correction for multiple comparisons. CONCLUSIONS: This pilot study demonstrates that randomization to exercise and metformin elicit unique effects on myokine concentrations in cancer patients. This hypothesis-generating observation warrants further basic, translational and clinical investigation and replication.

Prospects and challenges of tissue-derived extracellular vesicles (Ti-EVs).

Extracellular vesicles (EVs) are considered a vital component of cell-to-cell communication and represent a new frontier in diagnostics and a means to identify pathways for therapeutic intervention. Recently, studies have revealed the importance of tissue-derived EVs (Ti-EVs), which are EVs present in the interstitial spaces between cells, as they better represent the underlying physiology of complex, multicellular tissue microenvironments in biology and disease. EVs are native, lipid bilayer membrane nano-sized particles produced by all cells that are packaged with varied functional biomolecules including proteins, lipids, and nucleic acids. They are implicated in short- and long-range cellular communication and may elicit functional responses in recipient cells. To date, studies have often utilized cultured cells or biological fluids as a source for EVs that do not capture local molecular signatures of the tissue microenvironment. Recent work utilizing Ti-EVs has elucidated novel biomarkers for disease and provided insights into disease mechanisms that may lead to the development of novel therapeutic agents. Still, there are considerable challenges facing current studies. This review explores the vast potential and unique challenges for Ti-EV research and provides considerations for future studies that seek to advance this exciting field.

Botensilimab plus balstilimab in relapsed/refractory microsatellite stable metastatic colorectal cancer: a phase 1 trial.

Microsatellite stable metastatic colorectal cancer (MSS mCRC; mismatch repair proficient) has previously responded poorly to immune checkpoint blockade. Botensilimab (BOT) is an Fc-enhanced multifunctional anti-cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) antibody designed to expand therapy to cold/poorly immunogenic solid tumors, such as MSS mCRC. BOT with or without balstilimab (BAL; anti-PD-1 antibody) is being evaluated in an ongoing expanded phase 1 study. The primary endpoint is safety and tolerability, which was evaluated separately in the dose-escalation portion of the study and in patients with MSS mCRC (using combined dose-escalation/dose-expansion data). Secondary endpoints include investigator-assessed RECIST version 1.1-confirmed objective response rate (ORR), disease control rate (DCR), duration of response (DOR) and progression-free survival (PFS). Here we present outcomes in 148 heavily pre-treated patients with MSS mCRC (six from the dose-escalation cohort; 142 from the dose-expansion cohort) treated with BOT and BAL, 101 of whom were considered response evaluable with at least 6 months of follow-up. Treatment-related adverse events (TRAEs) occurred in 89% of patients with MSS mCRC (131/148), most commonly fatigue (35%, 52/148), diarrhea (32%, 47/148) and pyrexia (24%, 36/148), with no grade 5 TRAEs reported and a 12% discontinuation rate due to a TRAE (18/148; data fully mature). In the response-evaluable population (n = 101), ORR was 17% (17/101; 95% confidence interval (CI), 10-26%), and DCR was 61% (62/101; 95% CI, 51-71%). Median DOR was not reached (NR; 95% CI, 5.7 months-NR), and median PFS was 3.5 months (95% CI, 2.7-4.1 months), at a median follow-up of 10.3 months (range, 0.5-42.6 months; data continuing to mature). The combination of BOT plus BAL demonstrated a manageable safety profile with no new immune-mediated safety signals and encouraging clinical activity with durable responses. ClinicalTrials.gov identifier: NCT03860272 .

Collaboration matters: A randomized controlled trial of patient-clinician collaboration in suicide risk assessment and intervention.

BACKGROUND: Clinician collaboration can help high-risk individuals to manage their suicidal crises. However, limited research has directly examined how higher patient-clinician collaboration during assessment and intervention can effectively reduce suicidal ideation. This novel randomized clinical trial compared a high vs. low level of patient-clinician collaboration by pairing commonly used assessment (Structured Interview vs. Narrative Assessment) and intervention approaches (Safety Planning Intervention vs. Crisis Response Planning). We hypothesized that the interventions involving higher (than lower) patient-clinician collaboration during assessment (Narrative Assessment) or intervention (Crisis Response Planning) would lead to larger reductions in suicidal ideation. METHODS: Eighty-two participants with a history of suicide ideation and/or attempts were randomly assigned to one of the four interventions varying in patient-clinician collaboration. After attrition, sixty-six participants completed the study. Suicidal ideation via ecological momentary assessment was measured 14 days before and 14 days after treatment. RESULTS: Although the severity of suicidal ideation decreased in all groups, the two groups that included highly collaborative assessment had larger pre-post reductions in suicidal ideation (Narrative Assessment+Safety Plan; dwithin = 0.26, and Narrative Assessment+Crisis Response Plan; dwithin = 0.19) than the groups that included a checklist-based assessment (Structured Interview). LIMITATIONS: Longer follow-up periods with a larger sample would have provided an understanding of the durability of intervention effects. CONCLUSION: Results suggest that the inclusion of higher patient-clinician collaboration techniques during suicide risk assessment can effectively reduce suicidal thoughts. Thus, clinician-led collaborative risk assessment approaches can enhance the effects of safety planning-type interventions among patients with elevated risk for suicide versus checklist-based assessment approaches.

Relapsing Anti-GAD65-Associated Encephalitis Responsive to Thymoma Resection, Radiation, and Immunomodulatory Therapy.

Herein we describe a case of relapsing anti-GAD65-associated encephalitis which was responsive to the combination of thymoma resection, external beam radiotherapy, and immunomodulatory therapy. The case illustrates the value of remaining vigilant for the possibility of paraneoplastic syndromes in the context of anti-GAD65 antibodies and thymoma. It also illustrates that tumor-directed therapies may offer additional benefit beyond immunomodulatory therapy alone.

The distribution of beneficial mutational effects between two sister yeast species poorly explains natural outcomes of vineyard adaptation.

Domesticated strains of Saccharomyces cerevisiae have adapted to resist copper and sulfite, two chemical stressors commonly used in winemaking. S. paradoxus , has not adapted to these chemicals despite being consistently present in sympatry with S. cerevisiae in vineyards. This contrast represents a case of apparent evolutionary constraints favoring greater adaptive capacity in S. cerevisiae . In this study, we used a comparative mutagenesis approach to test whether S. paradoxus is mutationally constrained with respect to acquiring greater copper and sulfite resistance. For both species, we assayed the rate, effect size, and pleiotropic costs of resistance mutations and sequenced a subset of 150 mutants isolated from our screen. We found that the distributions of mutational effects displayed by the two species were very similar and poorly explained the natural pattern. We also found that chromosome VIII aneuploidy and loss of function mutations in PMA1 confer copper resistance in both species, whereas loss of function mutations in REG1 were only a viable route to copper resistance in S. cerevisiae . We also observed a single de novo duplication of the CUP1 gene in S. paradoxus but none in S. cerevisiae . For sulfite, loss of function mutations in RTS1 and KSP1 confer resistance in both species, but mutations in RTS1 have larger average effects in S. paradoxus . Our results show that even when the distributions of mutational effects are largely similar, species can differ in the adaptive paths available to them. They also demonstrate that assays of the distribution of mutational effects may lack predictive insight concerning adaptive outcomes.

Contextual and psychosocial factors influencing drug reward in humans: The importance of non-drug reinforcement.

The reinforcing efficacy, or behavior-strengthening effect, of a substance is a critical determinant of substance use typically quantified by measuring behavioral allocation to the substance under schedules of reinforcement with escalating response requirements. Although responses on these tasks are often used to indicate stable reinforcing effects or trait-level abuse potential for an individual, task designs often demonstrate within-person variability across varying degrees of a constraint within experimental procedures. As a result, quantifying behavioral allocation is an effective approach for measuring the impact of contextual and psychosocial factors on substance reward. We review studies using laboratory self-administration, behavioral economic purchase tasks, and ambulatory assessments to quantify the impact of various contextual and psychosocial factors on behavioral allocation toward consumption of a substance. We selected these assessment approaches because they cover the translational spectrum from experimental control to ecological relevance, with consistent support across these approaches representing greater confidence in the effect. Conceptually, we organized factors that influence substance value into two broad categories: factors that influence the cost/benefit ratio of the substance (social context, stress and affect, cue exposure), and factors that influence the cost/benefit ratio of an alternative (alternative non-drug reinforcers, alternative drug reinforcers, and opportunity costs). We conclude with an overview of future research directions and considerations for clinical application.

Toxin for Treating Raynaud Conditions in Hands (The TORCH Study): A Systematic Review and Meta-analysis.

Background: Raynaud disease of the hands is a complex disorder resulting in inappropriate constriction and/or insufficient dilation in microcirculation. There is an emerging role for botulinum toxin type A (BTX-A) in the treatment armamentarium for refractory Raynaud disease. The aim of this systematic review was to critically evaluate the management of primary and secondary Raynaud disease treated with BTX-A intervention. Methods: We performed a Preferred Reporting Items for Systematic Reviews and Meta-Analyses-compliant systematic review of clinical studies assessing treatment of primary or secondary Raynaud disease with BTX-A by searching Ovid MEDLINE and Embase databases from inception to first August 2023. The review protocol was prospectively registered on the PROSPERO database (CRD42022312253). Results: Our search strategy identified 288 research articles, of which 18 studies [four randomized controlled trials (RCTs), two non-RCTs, five case series, and seven retrospective cohort studies] were eligible for analysis. Meta-analysis demonstrated that the probability of pain visual analog scale score improvement with BTX-A intervention was 81.95% [95% confidence interval (74.12-87.81) P = 0.19, heterogeneity I 2 = 26%] and probability of digital ulcer healing was 79.37% [95% confidence interval (62.45-89.9) P = 0.02, heterogeneity I 2 = 56%]. Conclusions: Delivery of BTX-A to digital vessels in the hand may be an effective management strategy for primary and secondary Raynaud disease. A definitive, appropriately-powered RCT with objective functional and patient-reported outcome measures is required to accurately assess and quantify the efficacy of BTX-A in Raynaud disease of the hands.

Restoring adiponectin via rosiglitazone ameliorates tissue wasting in mice with lung cancer.

AIM: To investigate systemic regulators of the cancer-associated cachexia syndrome (CACS) in a pre-clinical model for lung cancer with the goal to identify therapeutic targets for tissue wasting. METHODS: Using the Kras/Lkb1 (KL) mouse model, we found that CACS is associated with white adipose tissue (WAT) dysfunction that directly affects skeletal muscle homeostasis. WAT transcriptomes showed evidence of reduced adipogenesis, and, in agreement, we found low levels of circulating adiponectin. To preserve adipogenesis and restore adiponectin levels, we treated mice with the PPAR-γ agonist, rosiglitazone. RESULTS: Rosiglitazone treatment increased serum adiponectin levels, delayed weight loss, and preserved skeletal muscle and adipose tissue mass, as compared to vehicle-treated mice. The preservation of muscle mass with rosiglitazone was associated with increases in AMPK and AKT activity. Similarly, activation of the adiponectin receptors in muscle cells increased AMPK activity, anabolic signaling, and protein synthesis. CONCLUSION: Our data suggest that PPAR-γ agonists may be a useful adjuvant therapy to preserve tissue mass in lung cancer.

Bruegel's Landscape with the Fall of Icarus.

Ovid's Metamorphoses tells the story of Icarus - his tragic flight with man-made wings, the melting of the wax that bound them, and the ensuing fall to his death. This moment has been immortalized across the arts and through several mediums, but none are more notable than Bruegel's Landscape with the Fall of Icarus. Described as a "painter for poets," Bruegel's work served as inspiration for several writers, with this piece in particular providing the basis for ekphrastic poems by W.H. Auden and William Carlos Williams. Though each of these works has a different focus, the unifying theme is that human tragedy is too often placed on the periphery of notice. They are effective reminders to physicians and other healthcare providers about the human aspect of suffering and pain in medicine.

Revealing the Singlet Fission Mechanism for a Silane-Bridged Thienotetracene Dimer.

Tetraceno[2,3-b]thiophene is regarded as a strong candidate for singlet fission-based solar cell applications due to its mixed characteristics of tetracene and pentacene that balance exothermicity and triplet energy. An electronically weakly coupled tetraceno[2,3-b]thiophene dimer (Et2Si(TIPSTT)2) with a single silicon atom bridge has been synthesized, providing a new platform to investigate the singlet fission mechanism involving the two acene chromophores. We study the excited state dynamics of Et2Si(TIPSTT)2 by monitoring the evolution of multiexciton coupled triplet states, 1TT to 5TT to 3TT to T1 + S0, upon photoexcitation with transient absorption, temperature-dependent transient absorption, and transient/pulsed electron paramagnetic resonance spectroscopies. We find that the photoexcited singlet lifetime is 107 ps, with 90% evolving to form the TT state, and the complicated evolution between the multiexciton states is unraveled, which can be an important reference for future efforts toward tetraceno[2,3-b]thiophene-based singlet fission solar cells.

The subjective value of social context in people who use cannabis.

Disordered cannabis use is linked to social problems, which could be explained by a subjective devaluation of nondrug social contexts and/or an overvaluation of cannabis-paired options relative to nondrug alternatives. To examine these hypotheses, measures to assess the subjective value of social- and/or cannabis-paired contexts were collected in people who use cannabis (n = 85) and controls (n = 98) using crowdsourcing methods. Measures included a cued concurrent choice task that presented two images (cannabis, social, social cannabis, and neutral images) paired with monetary options, hypothetical purchase tasks that included access to social parties with and without a cannabis "open bar," and the Social Anhedonia Scale (SAS). Little evidence was found to suggest that the cannabis group undervalued social contexts. People who used cannabis demonstrated a preference for social- versus neutral-cued options, and no preference for cannabis- versus social cannabis-cued options on the choice task. In addition, social party demand and SAS scores did not differ between groups. In contrast, we observed evidence for an overvaluation of cannabis context in people who use cannabis, including preference for social cannabis- versus social-cued options, and more disadvantageous choices for cannabis-cued options on the choice task, as well as more intense and inelastic demand for the social cannabis party compared to the social party. These results suggest that social problems associated with cannabis use could be at least partially explained by an overvaluation of cannabis-paired options, rather than devaluation of nondrug social-paired options, in the value calculations underlying drug use decisions. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Helical sulfonyl-γ-AApeptides for the inhibition of HIV-1 fusion and HIF-1α signaling.

Synthetic helical peptidic foldamers show promising applications in chemical biology and biomedical sciences by mimicking protein helical segments. Sulfonyl-γ-AApeptide helices developed by our group exhibit good chemodiversity, predictable folding structures, proteolytic resistance, favorable cell permeability, and enhanced bioavailability. Herein, in this minireview, we highlight two recent examples of homogeneous left-handed sulfonyl-γ-AApeptide helices to modulate protein-protein interactions (PPIs). One is sulfonyl-γ-AApeptides as anti-HIV-1 fusion inhibitors mimicking the helical C-terminal heptad repeat (CHR), which show excellent anti-HIV-1 activities through tight binding with the N-terminal heptad repeat (NHR) and inhibiting the formation of the 6-helical bundle (HB) structure. Another example is helical sulfonyl-γ-AApeptides disrupting hypoxia-inducible factor 1α (HIF-1α) and p300 PPI, thus selectively inhibiting the relevant signaling cascade. We hope these findings could help to elucidate the principles of the structural design of sulfonyl-γ-AApeptides and inspire their future applications in PPI modulations.

NKCC1 in Neonatal Cochlear Support Cells Reloads Ions Necessary for Cochlear Spontaneous Activity.

In the auditory system, the spontaneous activity of cochlear inner hair cells (IHCs) is initiated by the release of ATP from inner supporting cells (ISCs). This ATP release sets off a cascade, activating purinergic autoreceptors, opening of Ca2+-activated Cl- channel TMEM16A, Cl- efflux and osmotic cell shrinkage. Then, the shrunken ISCs efficiently regain their original volume, suggesting the existence of mechanisms for refilling Cland K+, priming them for subsequent activity. This study explores the potential involvement of NKCCs (Na+-K+-Cl- cotransporters) and KCCs (K+-Cl- cotransporters) in ISC spontaneous activity, considering their capability to transport both Cl- and K+ ions across the cell membrane. Employing a combination of immunohistochemistry, pharmacological interventions, and shRNA experiment, we unveiled the pivotal role of NKCC1 in cochlear spontaneous activity. Immunohistochemistry revealed robust NKCC1 expression in ISCs, persisting until the 2nd postnatal week. Intriguingly, we observed a developmental shift in NKCC1 expression from ISCs to synaptophysin-positive efferent terminals at postnatal day 18, hinting at its potential involvement in modulating synaptic transmission during the post-hearing period. Experiments using bumetanide, a well-known NKCC inhibitor, supported the functional significance of NKCC1 in ISC spontaneous activity. Bumetanide significantly reduced the frequency of spontaneous extracellular potentials (sEP) and spontaneous optical changes (sOCs) in ISCs. NKCC1-shRNA experiments conducted in cultured cochlear tissues further supported these findings, demonstrating a substantial decrease in event frequency and area. Taken together, we revealed the role of NKCC1 in shaping the ISC spontaneous activity that govern auditory pathway development.

Efficiently Quantifying Egocentric Social Network Cannabis Use: Initial Psychometric Validation of the Brief Cannabis Social Density Assessment.

OBJECTIVE: Social environment is a key determinant of substance use, but cannabis-related social network analysis is not common, in part due to the assessment burden of comprehensive egocentric social network analysis. METHOD: The current pre-registered secondary analysis assessed the psychometric properties (i.e., convergent, criterion-related, incremental validity) of the Brief Cannabis Social Density Assessment (B-CaSDA) in a cross-sectional sample of adults who use cannabis (N = 310) using a survey-based design. The B-CaSDA assesses the quantity and frequency of cannabis use for the respondent's four closest (non-parent) relationships. RESULTS: Cannabis use severity was elevated for each additional person who used cannabis at all or daily in the individual's social network. B-CaSDA indices (i.e., frequency, quantity, total score) were positively correlated with cannabis consumption, cannabis use severity indicators, and established risk factors for harmful cannabis use. B-CaSDA indices also discriminated between those above and below a clinical cutoff on the Cannabis Use Disorder Identification Test - Revised (CUDIT-R). Finally, in omnibus models that included common risk factors for cannabis use severity, the B-CaSDA quantity index contributed additional variance when predicting CUDIT-R total score, and B-CaSDA frequency contributed additional variance in predicting the CUDIT-R quantity-frequency subscale. CONCLUSIONS: The results suggest that the B-CaSDA has the potential to expand social network research on cannabis use and misuse by increasing its assessment feasibility in diverse designs.

Micro-Coring: A Novel Approach to Perioral Rejuvenation.

BACKGROUND: A long philtrum and poor perioral skin quality are stigmata of the aging face. Micro-coring is a novel technology that allows for scarless skin removal. OBJECTIVES: This study aimed to determine if micro-coring can shorten the philtrum and improve perioral skin quality. METHODS: A retrospective cohort study was performed on subjects who underwent facelift with perioral micro-coring and age/BMI-matched control patients who underwent facelift alone. Preoperative and postoperative three-dimensional facial imaging was performed. Standard perioral distances and percent change were calculated. Perioral skin quality was evaluated by blinded raters using the Scientific Assessment Scale of Skin Quality (SASSQ) and Global Aesthetic Improvement Scale (GAIS). RESULTS: Thirteen subjects and thirteen controls were included with a mean follow-up of 8.9 months (range 3.0-21.5). Subjects had significantly shorter mean philtral length postoperatively as compared to preoperatively, with an average decrease of 6.18% (±2.25%) (p<0.05). Controls did not experience significant changes in philtrum length (p>0.05). Postoperative philtrum length was significantly shorter in subjects as compared to controls (p<0.05). There were no significant changes in other perioral measurements. Perioral skin elasticity and wrinkles significantly improved in subjects as compared to controls and subjects had significantly greater GAIS scores (p<0.05). CONCLUSIONS: Micro-coring can achieve perioral rejuvenation through measurable shortening of the philtrum and observable improvement in skin quality. Non-surgical techniques continue to find new ways to achieve aesthetic goals without significant recovery or scarring and offer value to patients and clinicians.

Clinical outcomes of adjuvant nivolumab in resected stage III melanoma: comparison of CheckMate 238 trial and real-world data.

OBJECTIVES: Nivolumab is approved as adjuvant therapy for resected stage III/IV melanoma based on the phase 3 CheckMate 238 trial. This analysis compared outcomes from CheckMate 238 with those from the real-world Flatiron Health electronic health record-derived de-identified database in patients with resected stage III melanoma (per AJCC-8) treated with adjuvant nivolumab. MATERIALS: Outcomes included baseline characteristics, overall survival (OS) in the CheckMate 238 cohort (randomization until death or last known alive), and real-world overall survival (rwOS) in the Flatiron Health cohort (nivolumab initiation until death or data cutoff). rwOS was compared with OS using unadjusted and adjusted Cox proportional hazards models. Inverse probability of treatment weighting (IPTW) was combined with the adjusted model to reduce baseline discrepancies. RESULTS: The CheckMate 238 and real-world cohorts included 369 and 452 patients, respectively (median age, 56.0 and 63.0 years; median follow-up, 61.4 vs. 25.5 months). rwOS was not different from OS in the unadjusted (hazard ratio [HR] 1.27; 95% CI 0.92-1.74), adjusted (HR 1.01; 95% CI 0.67-1.54), and adjusted IPTW (HR 1.07; 95% CI 0.70-1.63) analyses. In the adjusted analysis, 2-year OS and rwOS rates were 84%. Median OS and rwOS were not reached. After IPTW, OS and rwOS were not different (HR 1.07; 95% CI 0.70-1.64). CONCLUSIONS: In this comparative analysis, OS in the CheckMate 238 trial was similar to rwOS in the Flatiron Health database after adjustments in patients with resected stage III melanoma (per AJCC-8) treated with adjuvant nivolumab, validating the trial results.

Impact of proton PBS machine operating parameters on the effectiveness of layer rescanning for interplay effect mitigation in lung SBRT treatment.

BACKGROUND: Rescanning is a common technique used in proton pencil beam scanning to mitigate the interplay effect. Advances in machine operating parameters across different generations of particle therapy systems have led to improvements in beam delivery time (BDT). However, the potential impact of these improvements on the effectiveness of rescanning remains an underexplored area in the existing research. METHODS: We systematically investigated the impact of proton machine operating parameters on the effectiveness of layer rescanning in mitigating interplay effect during lung SBRT treatment, using the CIRS phantom. Focused on the Hitachi synchrotron particle therapy system, we explored machine operating parameters from our institution's current (2015) and upcoming systems (2025A and 2025B). Accumulated dynamic 4D dose were reconstructed to assess the interplay effect and layer rescanning effectiveness. RESULTS: Achieving target coverage and dose homogeneity within 2% deviation required 6, 6, and 20 times layer rescanning for the 2015, 2025A, and 2025B machine parameters, respectively. Beyond this point, further increasing the number of layer rescanning did not further improve the dose distribution. BDTs without rescanning were 50.4, 24.4, and 11.4 s for 2015, 2025A, and 2025B, respectively. However, after incorporating proper number of layer rescanning (six for 2015 and 2025A, 20 for 2025B), BDTs increased to 67.0, 39.6, and 42.3 s for 2015, 2025A, and 2025B machine parameters. Our data also demonstrated the potential problem of false negative and false positive if the randomness of the respiratory phase at which the beam is initiated is not considered in the evaluation of interplay effect. CONCLUSION: The effectiveness of layer rescanning for mitigating interplay effect is affected by machine operating parameters. Therefore, past clinical experiences may not be applicable to modern machines.