Daily Anesthesiology Research Analysis
Analyzed 29 papers and selected 3 impactful papers.
Summary
Today's most impactful anesthesiology-related papers span perioperative pathophysiology and critical care: a mechanistic study identifies glial connexin-43 as a druggable driver of postoperative ileus, a prospective ICU study links paradoxical breathing and respiratory muscle remodeling to early weaning failure after spinal trauma, and preclinical work details how dexmedetomidine activates AMPK/PGC-1α/CPT1A to mitigate renal ischemia-reperfusion injury.
Research Themes
- Perioperative pathophysiology and organ protection
- Ventilator weaning and respiratory muscle dynamics after spinal trauma
- Translational targets to prevent postoperative ileus
Selected Articles
1. Glial Connexin-43 is a pathogenic mechanism promoting gut inflammation after postsurgical intestinal manipulation with potential relevance to humans.
This mechanistic study shows that enteric glial connexin-43 is upregulated after surgical intestinal manipulation and drives inflammation, immune activation, and neuropathy underlying postoperative ileus. Genetic deletion or peptide inhibition (43Gap26) of glial Cx43 dampened pro-inflammatory signaling and protected against POI features, with supportive signals observed in human surgical tissue and human enteric glial cells.
Impact: Identifies a tractable, glia-specific signaling node (Cx43 hemichannels) that links surgical trauma to postoperative ileus with cross-species validation, opening a new therapeutic avenue in perioperative care.
Clinical Implications: Blocking glial Cx43 signaling could prevent or mitigate postoperative ileus; perioperative trials of Cx43 modulators or repurposed gap junction inhibitors may be warranted, alongside biomarker development for enteric gliosis.
Key Findings
- Cx43 is the highest-expressed connexin in enteric glia in mice and humans and is upregulated after surgical trauma and in POI-related models.
- Glial Cx43 deletion reduced glial reactivity, pro-inflammatory signaling, immune cell activation, and prevented enteric neuropathy in a mouse POI model.
- IL-1β opened Cx43 hemichannels in human enteric glial cells, increasing IL-6 and CCL2 release; the peptide inhibitor 43Gap26 blocked these responses.
- Patient intestinal trauma samples showed Cx43 upregulation paralleling mouse POI inflammation and enteric gliosis.
Methodological Strengths
- Multi-system validation: mouse POI model, human enteric glial cells, and patient surgical tissues
- Both genetic (glial Cx43 conditional knockout) and pharmacologic (43Gap26) loss-of-function approaches
Limitations
- Predominantly preclinical evidence; clinical efficacy of Cx43 inhibitors for POI remains untested
- Quantitative human sample sizes and longitudinal clinical outcomes were not detailed
Future Directions: Develop selective, clinically viable Cx43 hemichannel modulators; test efficacy and safety in large animal models and early-phase perioperative trials with gliosis/inflammation biomarkers.
BACKGROUND & AIMS: Abdominal surgery often precipitates postoperative ileus (POI), a frequent and severe GI motility disorder, through mechanisms that involve intestinal inflammation. Emerging data show that enteric glia acquire a reactive phenotype and that aggravates POI but how glia exert this effect remains unclear. Enteric glia express connexin-43 hemichannels (gCx43), which are implicated in neurological and inflammatory disorders. Thus, we aimed to decipher contributions of glial Cx43 in the pathophysiology of POI. METHODS: We induced POI in mice using in vivo intestinal manipulation and used glial Cx43cKO (Sox10 RESULTS: Cx43 is the highest expressed connexin in enteric glia in mice and humans. Up-regulation of Cx43 occurs in various disease models linked to POI, GI surgical trauma, inflammation, immune cell activation, and enteric gliosis. In the mouse POI model, glial Cx43-deletion reduces glial reactivity, pro-inflammatory signals, upregulates host protection genes, regulates immune cell activation and prevents enteric neuropathy. In hEGCs, IL-1β induction opens Cx43 and stimulates release of IL-6 and CCL2. The Cx43 peptide inhibitor, 43Gap26, inhibits glial Cx43 activation, reduces IL-6 release, blocks up-regulation of macrophage activation factors, and immune cell regulation factors. Surgical intestinal trauma in patients up-regulates Cx43 during inflammation and enteric gliosis in mouse POI. CONCLUSIONS: Glial Cx43 signaling promotes enteric gliosis, and immune cell activation, inflammation, enteric neuropathy in mice with potential translatability to humans after intestinal surgical trauma and mechanical stress in POI. Interventions that block glial Cx43 activation may be protective against POI development.
2. Respiratory Muscle Activity and Weaning from Mechanical Ventilation after Spinal Trauma: The ACCESSIT Study.
In a prospective ICU cohort of 30 spinal trauma patients, paradoxical breathing patterns and remodeling of respiratory muscles (thinner internal oblique, thicker parasternal intercostal) strongly predicted early weaning failure, independent of SCI status. Noninvasive Konno-Mead loop metrics yielded an AUC of 0.95 for early failure, highlighting actionable physiology.
Impact: Introduces a practical, multimodal physiologic framework to risk-stratify weaning attempts after spinal trauma, with high discriminative accuracy using noninvasive signals.
Clinical Implications: Bedside assessment of paradoxical breathing and targeted ultrasound of respiratory muscles can guide timing of weaning trials and early rehabilitation strategies, potentially reducing failed attempts and ICU morbidity.
Key Findings
- Paradoxical breathing (larger Konno-Mead loop areas) strongly associated with early weaning failure (AUC 0.95; 95% CI 0.80–1.00).
- Inward rib cage motion was more frequent in failures (70%) vs successes (27%) with P = .05.
- Failure patients had reduced internal oblique thickness (4.0 ± 0.7 vs 5.2 ± 1.3 mm; P = .03) and increased parasternal intercostal thickness (3.2 ± 1.2 vs 2.3 ± 0.6 mm; P = .07), with ORs of 0.88 and 1.16 respectively.
- Findings were independent of the presence of spinal cord injury; 60% weaned on first attempt; 13.3% ICU mortality.
Methodological Strengths
- Prospective design with pre-specified physiologic assessments and trial registration (NCT05207046)
- Multimodal noninvasive measurements (RIP, ultrasound, surface EMG) with robust statistical modeling (logistic and time-dependent Cox)
Limitations
- Single-center study with small sample size (N = 30) limits generalizability
- Some associations were borderline (e.g., parasternal intercostal thickness P = .07) and outcomes limited to first weaning attempt
Future Directions: Validate thresholds in multicenter cohorts, integrate into ventilator weaning protocols, and test targeted interventions (e.g., respiratory muscle training) in RCTs guided by these physiologic markers.
RATIONALE: Spinal trauma, especially when associated with spinal cord injury (SCI), can impair respiratory muscle function and complicate early weaning from mechanical ventilation (MV). OBJECTIVES: In patients admitted for spinal trauma requiring MV, to prospectively assess and monitor the coordination, structure, and activity of non-invasively accessible respiratory muscles, in relation to weaning outcomes up to the first weaning attempt. METHODS: We enrolled adult patients with traumatic spine injury, requiring MV in the Trauma-Neuro intensive care unit (ICU) at St. Micheal's Hospital in Toronto. Rib cage-abdomen synchrony was assessed with respiratory inductive plethysmography, while respiratory muscle thickness and activity were measured with ultrasound and surface electromyography. Patients not expected to survive the first 48 hours were not included. The relationship between muscle parameters and weaning outcome was assessed through logistic regression and time dependent Cox proportional hazards models. RESULTS: We enrolled 30 trauma patients: 67% male, median age 48 (35-64); half had confirmed SCI. Four (13.3%) died in ICU and 18 (60%) were weaned at first attempt, with no difference between SCI and non-SCI. Konno-Mead plots suggested strong association between paradoxical breathing and early weaning failure, with larger total and inspiratory loop area (normalized to tidal volume) in patients who failed weaning (Area Under the Curve = 0.95 [95%CI 0.80-1.00]), regardless of the SCI status. Paradoxical inward rib cage movement was observed in 70% of failure patients vs. 27% in success, P = .05). Failure patients had progressive reduced internal oblique thickness (4.0 ± 0.7 vs 5.2 ± 1.3 mm, P = .03) and increased parasternal intercostal thickness (3.2 ± 1.2 vs 2.3 ± 0.6 mm, P = .07), both being associated with probability of early weaning failure (OR = 0.88 and OR = 1.16, respectively). CONCLUSIONS: Paradoxical breathing, inward thoracic inspiratory motion and changes in respiratory muscle thickness characterize early weaning failure after spinal trauma, independently of SCI presence. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT05207046. PRIMARY SOURCE OF FUNDING: St. Michael's Hospital Medical Services Association (2022-23 Innovation Funds).
3. Dexmedetomidine regulates fatty acid oxidation through the AMPK/PGC-1α/CPT1A pathway to mitigate renal ischaemia-reperfusion injury.
Dexmedetomidine improved renal function and reduced oxidative stress and lipid accumulation after ischemia-reperfusion, while activating AMPK/PGC-1α/CPT1A to enhance fatty acid oxidation and preserve mitochondria. Molecular docking suggested direct AMPK interaction, and pharmacologic inhibition with Compound C abrogated protection, supporting pathway causality.
Impact: Provides a mechanistic basis for the renoprotective effects of a widely used anesthetic adjunct, guiding biomarker selection and dosing hypotheses for perioperative AKI prevention trials.
Clinical Implications: Supports testing perioperative dexmedetomidine strategies for AKI mitigation with mechanistic biomarkers (e.g., phospho-AMPK, FAO markers), while acknowledging the need for dose-response and safety evaluation in humans.
Key Findings
- Dex improved renal function and histopathology after I/R and reduced oxidative stress (↓MDA, ↑SOD) and lipid accumulation (↓FFA, ↓TG).
- Activated AMPKα phosphorylation and increased PGC-1α and CPT1A expression at protein and mRNA levels in vivo and in vitro.
- TEM showed preserved mitochondrial ultrastructure and fewer lipid droplets with Dex.
- Molecular docking indicated strong Dex–AMPK binding; AMPK inhibition with Compound C reversed protective effects.
Methodological Strengths
- Convergent in vivo and in vitro models with multimodal endpoints (biochemistry, gene/protein expression, TEM)
- Mechanistic validation using pathway inhibition (Compound C) and in silico docking
Limitations
- Preclinical models without clinical outcome data; species/dose translation uncertain
- Docking suggests but does not prove direct binding; off-target effects not fully excluded
Future Directions: Define dose–response and timing in large-animal models; conduct early-phase perioperative AKI trials incorporating FAO/AMPK biomarkers and mitochondrial endpoints.
OBJECTIVE: This study aimed to investigate whether dexmedetomidine (Dex) attenuates renal ischaemia-reperfusion injury (RIRI) by regulating fatty acid oxidation and to explore its underlying mechanisms. METHODS: A renal ischaemia-reperfusion (I/R) model was established in Sprague-Dawley rats, and a hypoxia/reoxygenation model was established using human proximal renal tubule epithelial cells. Renal function was evaluated by measuring serum creatinine and blood urea nitrogen. Oxidative stress markers malondialdehyde (MDA) and superoxide dismutase (SOD), lipid accumulation free fatty acids (FFA), triglycerides (TG) and apoptosis were assessed. Protein and mRNA expression levels of adenosine monophosphate-activated protein kinase (AMPK), peroxisome proliferator-activated receptor γ coactivator 1 alpha (PGC-1α) and carnitine palmitoyl transferase 1 A (CPT1A) were analysed by Western blot, quantitative real-time polymerase chain reaction and immunohistochemistry. Mitochondrial ultrastructure and intracellular lipid droplets were examined by transmission electron microscopy (TEM). Molecular docking was performed to predict the interaction between Dex and AMPK, and functional validation was performed using the AMPK inhibitor Compound C. RESULTS: Dexmedetomidine significantly improved renal function and ameliorated histopathological damage in rats with I/R. It reduced oxidative stress (decreased MDA, increased SOD activity) and attenuated lipid accumulation (reduced FFA and TG levels)， enhancing adenosine triphosphate production in both in vivo and in vitro models. Furthermore, Dex upregulated the phosphorylation of AMPKα, the expression of PGC-1α and CPT1A at both protein and mRNA levels. The TEM revealed that Dex preserved mitochondrial integrity and reduced lipid droplet accumulation in renal tubular cells. Molecular docking indicated a strong binding affinity between Dex and AMPK, and the protective effects of Dex were reversed by Compound C. CONCLUSION: Dexmedetomidine alleviates RIRI by reducing oxidative stress and promoting fatty acid oxidation through the AMPK/PGC-1α/CPT1A pathway. This study provides a potential therapeutic mechanism for the use of Dex in mitigating RIRI.