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Grafting has been widely used to improve horticultural traits. It has also served increasingly as a tool to investigate the long-distance transport of molecules that is an essential part for key biological processes. Many studies have revealed the molecular mechanisms of graft-induced phenotypic variation in anatomy, morphology and production. Here, we review the phenomena and their underlying mechanisms by which macromolecules, including RNA, protein, and even DNA, are transported between scions and rootstocks via vascular tissues. We further propose a conceptual framework that characterizes and quantifies the driving mechanisms of scion–rootstock interactions toward vascular reconnection and regeneration.

Grafting is an ancient cloning method that has been used widely for thousands of years in agricultural practices. Graft-union development is also an intricate process that involves substantial changes such as organ regeneration and genetic material exchange. However, the molecular mechanisms for graft-union development are still largely unknown. Here, a micrografting method that has been used widely in Arabidopsis was improved to adapt it a smooth procedure to facilitate sample analysis and to allow it to easily be applied to various dicotyledonous plants. The developmental stage of the graft union was characterized based on this method. Histological analysis suggested that the transport activities of vasculature were recovered at 3 days after grafting (dag) and that auxin modulated the vascular reconnection at 2 dag. Microarray data revealed a signal-exchange process between cells of the scion and stock at 1 dag, which re-established the communication network in the graft union. This process was concomitant with the clearing of cell debris, and both processes were initiated by a wound-induced programme. The results demonstrate the feasibility and potential power of investigating various plant developmental processes by this method, and represent a primary and significant step in interpretation of the molecular mechanisms underlying graft-union development.

Grafting has been practiced for millennia to combine the best characteristics of two plants. Despite recent molecular discoveries that gain insight into plant grafting, the systematic characterization of its underlying mechanisms is still lacking. Here, we take a step toward filling this gap by developing a generalized statistical mechanics model to decode genomic crosstalk between the scion and rootstock. Instead of traditional objectives of identifying individual genes that are differentially expressed between the two organs, our model codes thousands of interactive genes into informative, dynamic, omnidirectional, and personalized networks (idopNetworks) that program and rewire scion‐rootstock crosstalk. We design an experiment of reciprocally micrografting young tissues to validate the application of idopNetworks to the genomic characterization of graft formation between two distantly related Populus species. Given its capacity to reveal the most comprehensive genomic underpinnings for proper interactions of the scion with rootstock to develop new plants, the idopNetworks model can be extended for the mechanistic exploration of a wide range of biological, evolutionary, and medical phenomena. We introduce a statistical mechanics framework to decode the genomic crosstalk governing plant grafting. By integrating evolutionary game theory with transcriptomics, we reconstruct idopNetworks (informative, dynamic, omnidirectional, and personalized networks) that map scion–rootstock interactions. This framework identifies hub genes driving vascular reconnection and compatibility, offering a unified computational strategy for dissecting complex tissue communication mechanisms.

Background: Cephalosomatic anastomosis (CSA) has never been attempted before in man as the transected spinal cords of the body donor and body recipient could not be \"fused\" back together. Recent advances made this possible. Here, we report on the surgical steps necessary to reconnect a head to a body at the cervical level. Methods: Full rehearsal of a CSA on two recently deceased human cadavers was performed at Harbin Medical University, Harbin, China. Results: The surgery took 18 hours to complete within the time frame planned for this surgery. Several advances resulted from this rehearsal, including optimization of the surgical steps, sparing of the main nerves (phrenics, recurrent laryngeal nerves), and assessment of vertebral stabilization. Conclusion: Several specialties are involved in a full-scale CSA, including neck surgery, vascular surgery, orthopedic surgery, plastic surgery, gastrointestinal surgery, and neurosurgery, as well as the operating staff. This rehearsal confirmed the surgical feasibility of a human CSA and further validated the surgical plan. Education and coordination of all the operating teams and coordination of the operative staff was achieved in preparation for the live human CSA.

Auxin is important in the development of plant vascular tissues. Reconnection of vascular bundles between scion and stock is a primary aim of grafting, and polar auxin transport greatly affects the formation of a continuous vascular model. The role of auxin in the process of graft-union development was studied by grafting the seedlings of Arabidopsis thaliana (L.) Heynh. DR5:GUS marker plants, which exert the auxinspecific responses. Auxin induced the DR5:GUS expression in the vascular bundles around graft surface and stimulated the formation of multiple vascular bundle reconnections on the third day after grafting (DAG). DR5:GUS expression was delayed for one day in both scion and stock and dramatically declined by the auxin transport inhibitor N-1-naphthylphthalamic acid (NPA). Vascular bundle reconnection was observed only on the 4th DAG. These results suggest that auxin stimulates the reconnection of the vascular bundles, whereas NPA inhibits it. We studied the role of PIN proteins in graft development by grafting seedlings of PIN:GUS plants. PIN had different expression patterns in the graft process. Expression levels of PIN genes were analyzed by real-time PCR. All PIN genes had the higher expression level at the third DAG. We conclude that auxin stimulates the development of graft unions, and the patterns of expressions of PIN family genes can affect the development of graft-union by controlling the auxin flow.

Background Pulsed field ablation (PFA) is a novel method of cardiac ablation where there is insufficient knowledge on the durability and reconnection patterns after pulmonary vein isolation (PVI). The aim of this study was to characterize the electrophysiological findings at time of repeat procedure in real-world atrial fibrillation (AF) patients. Methods Patients who underwent a repeat procedure ( n =26) for symptomatic recurrent arrhythmias after index first-time treatment with single-shot PFA PVI ( n =266) from July 2021 to June 2023 were investigated with 3D high-density mapping and ad-hoc re-ablation by radiofrequency or focal PFA. Results Index indication for PVI was persistent AF in 17 (65%) patients. The mean time to repeat procedure was 292 ± 119 days. Of the 26 patients (104 veins), complete durable PVI was observed in 11/26 (42%) with a durable vein isolation rate of 72/104 (69%). Two patients (8%) had all four veins reconnected. The posterior wall was durably isolated in 4/5 (80%) of the cases. The predominant arrhythmia mechanism was AF in 17/26 (65%) patients and regular atrial tachycardia (AT) in 9/26 (35%). Reconnection was observed 9/26 (35%) in right superior, 11/26 (42%) in right inferior, 7/26 (27%) in left superior, 5/26 (19%) in left inferior, p =0.31 between veins. The gaps were significantly clustered in the right-sided anterior carina compared to other regions ( P =0.009). Conclusions Durable PVI was observed in less than half of the patients at time of repeat procedure. No significant difference in PV reconnection pattern was observed, but the gap location was preferentially located at the anterior aspects of the right-sided PVs. Predominant recurrence was AF. More data is needed to establish lesion formation and durability and AT circuits after PFA.

Background A novel multipolar pulsed-field ablation (PFA) catheter has recently been introduced for pulmonary vein isolation (PVI). Pre-market data showed high rates for PVI-durability during mandatory remapping studies. Objective : To present post-market data in patients with recurrent arrhythmias. Methods Consecutive patients undergoing a redo procedure after an index PFA PVI using a bipolar-biphasic PFA system were included. 3-D electro-anatomical maps (3D-EAM) on redo procedure were compared to the 3D-EAM acquired after ablation during the index procedure. PVI durability was assessed on a per-vein and per-patient level and the sites of reconnections were identified. Furthermore, lesion extent around veins with durable isolation was compared to study lesion regression. Results Of 341 patients treated with a PFA PVI, 29 (8.5%) underwent a left atrial redo ablation due to arrhythmia recurrence. At the end of the index procedure, 110/112 veins (98%, four common ostia) were isolated. On redo procedures performed a median of 6 months after the first ablation, 3D-EAM identified 69/110 (63%) PVs with durable isolation. In 6 (21%) patients, all PVs were durably isolated. Reconnections were more often found on the right-sided veins and on the anterior aspects of the upper veins. Only minor lesion regression was observed between the index and redo procedure (a median of 3 mm (0 – 9.5) on the posterior wall). Conclusion In patients with arrhythmia recurrence after PFA PVI using a first-generation PFA device, durable isolation was observed in 63% of the veins and 21% of the patients showed durable isolation of all previously isolated veins. Graphical abstract

Background Pulmonary vein isolation (PVI) is the cornerstone of atrial fibrillation (AF) ablation. Despite promising success rates, redo ablation is sometimes required. At redo, PVs may be found to be isolated (silent) or reconnected. We studied patients with silent vs reconnected PVs at redo and analysed associations with adverse outcomes. Methods Patients undergoing redo AF ablations between 2013 and 2019 at our institution were included and stratified into silent PVs or reconnected PVs. The primary outcome was a composite of further redo ablation, non-AF ablation, atrioventricular nodal ablation, and death. Secondary outcomes included arrhythmia recurrence. Results A total of 467 patients were included with mean 4.6 ± 1.7 years follow-up, of whom 48 (10.3%) had silent PVs. The silent PV group had had more often undergone >1 prior ablation (45.8% vs 9.8%; p <0.001), had more persistent AF (62.5% vs 41.1%; p =0.005) and had more non-PV ablation performed both at prior ablation procedures and at the analysed redo ablation. The primary outcome occurred more frequently in those with silent PVs (25% vs 13.8%; p =0.053). Arrhythmia recurrence was also more common in the silent PV group (66.7% vs 50.6%; p =0.047). After multivariable adjustment, female sex (aHR 2.35 [95% CI 2.35–3.96]; p =0.001) and ischaemic heart disease (aHR 3.21 [95% CI 1.56–6.62]; p =0.002) were independently associated with the primary outcome, and left atrial enlargement (aHR 1.58 [95% CI 1.20–2.08]; p =0.001) and >1 prior ablation (aHR 1.88 [95% CI 1.30–2.72]; p <0.001) were independently associated with arrhythmia recurrence. Whilst a finding of silent PVs was not itself significant after multivariable adjustment, this provides an easily assessable parameter at clinically indicated redo ablation which informs the clinician of the likelihood of a worse future prognosis. Conclusions Patients with silent PVs at redo AF ablation have worse clinical outcomes.

In patients with atrial fibrillation (AF) recurrence after pulmonary vein (PV) isolation, noninvasive markers predicting PV reconnection or PV reconnection sites have not been fully elucidated. This study investigated the relationship between the P-wave terminal force in lead V1 (PTFV1) and the PV reconnection or reconnection site in patients with AF recurrence. We retrospectively studied consecutive patients who underwent second AF ablation between April 1, 2018, and June 1, 2023. PTFV1 was investigated before the first AF ablation (pre-ablation PTFV1) and before the second AF ablation (post-ablation PTFV1). In addition, we examined the ratio of the post-ablation to pre-ablation PTFV1 (PTFV1 ratio). These values were compared between patients with and without PV reconnection, with and without left PV (LPV) reconnection, and with and without right PV (RPV) reconnection. The analysis included 56 patients. PTFV1 was reduced because of the first AF ablation. In addition, the values were more decreased in patients without PV reconnection than with PV reconnection. The PTFV1 ratio was significantly smaller in the patients without LPV reconnection than with LPV reconnection; no significant difference was observed between the patients with and without RPV reconnection. Receiver operating characteristic curve analysis showed that a PTFV1 ratio > 0.69 predicted LPV reconnection with 70.0% sensitivity and 66.7% specificity. In conclusion, the PTFV1 ratio may be a noninvasive marker predicting LPV reconnection in patients with AF recurrence.

Background Cryoballoon ablation (CBA) is an established approach for rhythm management of atrial fibrillation (AF). We sought to assess balloon temperature (BT) parameters as predictors of pulmonary vein (PV) reconnection within the index procedure and AF recurrence following CBA. Methods BT was monitored in 119 AF patients undergoing CBA. PVs were assessed for reconnection during the procedure and patients were followed for arrhythmia recurrence. Results PV reconnection was identified in 39 (8.3%) of 471 PVs. BT was significantly colder in the absence of PV reconnection (30 s: − 33.5 °C [− 36; − 30] vs − 29.5 °C [− 35; − 25.5], p  = 0.001; 60 s: − 41 °C [− 44; − 37] vs − 36.5 °C [− 42; − 33.5], p  < 0.001; nadir: − 47 °C [− 52; − 43] vs − 41.5 °C [− 47; − 38], p  < 0.001). PV reconnection was associated with significantly longer time to reach − 15 °C and – 40 °C (14.5 s [11.5–18.5] vs 12 s [10–15.5], p  = 0.023; and 75 s [40–95.5] vs 46 s [37–66.75], p  = 0.005) and shorter rewarming time (5.75 s [4.75–8.5] vs 7 s [6–9], p  = 0.012). ROC analysis of these procedural parameters had an AUC = 0.71 in predicting PV reconnection. AF recurrence occurred in 51 (42.8%) patients. Kaplan–Meier analysis showed better arrhythmia-free survival for patients in whom BT decreased below – 40 °C in all PVs and patients who had no early PV reconnections, compared to patients in whom BT below – 40 °C was not achieved in at least one PV (log rank = 6.3, p  = 0.012) and patients who had PV reconnections (log rank = 4.1, p  = 0.043). Conclusions Slower BT decline, warmer BT nadir, and faster rewarming time predict early PV reconnection. Absence of early PV reconnections and BT dropping below – 40 °C in all PVs during CBA are associated with lower rates of AF recurrence.