Multiplexed analysis of macrophage polarisation in pulmonary metastases of microsatellite stable colorectal cancer.

Tumour-associated macrophages (TAMs) express a continuum of phenotypes ranging from an anti-tumoural M1-like phenotype to a pro-tumoural M2-like phenotype. During cancer progression, TAMs may shift to a more M2-like polarisation state, but the role of TAMs in CRC metastases is unclear. We conducted a comprehensive spatial and prognostic analysis of TAMs in CRC pulmonary metastases and corresponding primary tumours using multiplexed immunohistochemistry and machine learning-based image analysis. We obtained data from 106 resected pulmonary metastases and 74 corresponding primary tumours. TAMs in the resected pulmonary metastases were located closer to the cancer cells and presented a more M2-like polarised state in comparison to the primary tumours. Higher stromal M2-like macrophage densities in the invasive margin of pulmonary metastases were associated with worse 5-year overall survival (HR 3.19, 95% CI 1.35-7.55, p = 0.008). The results of this study highlight the value of multiplexed analysis of macrophage polarisation in cancer metastases and might have clinical implications in future cancer therapy.

Results of video-assisted thoracoscopic surgery versus thoracotomy for lung cancer in a mixed practice medium-volume hospital: a propensity-matched study.

OBJECTIVES: The aim of this study was to compare the short- and long-term results of video-assisted thoracoscopic surgery (VATS) and thoracotomy for non-small-cell lung cancer in a medium-volume centre, where cardiothoracic surgeons perform both cardiac and general thoracic surgery. The primary outcome of interest was 5-year overall survival and disease-specific survival. Secondary outcomes were short-term postoperative complications, length of hospital stay and lymph node yield. METHODS: This was a retrospective cohort study including 670 lung cancer patients undergoing VATS (n = 207) or open surgery (n = 463) with a curative intent in Oulu University Hospital between the years 2000-2020. Propensity score matching was implemented with surgical technique as the dependent and age, sex, Charlson comorbidity index, pulmonary function, pathological stage, histological type and the year of the operation as covariates resulting in 127 pairs. RESULTS: In the propensity-matched cohort, 5-year overall survival was 64.3% after VATS and 63.2% after thoracotomy (P = 0.969). Five-year disease-specific survival was 71.6% vs 76.2% (P = 0.559). There were no differences in overall (34.6% vs 44.9%, p = 0.096) or major postoperative complications (8.7% vs 14.2%, P = 0.167) between the study groups. The average length of hospital stay was shorter (5.8 vs 6.6 days, P = 0.012) and the median lymph node yield was lower (4.0 vs 7.0, P < 0.001) in the VATS group compared to the thoracotomy group. CONCLUSIONS: According to this study, the long-term results of lung cancer surgery in a mixed practice are comparable between VATS and open surgery.

Results of intention-to-treat pulmonary metastasectomies in northern Finland revealing significant number of new lung primary carcinomas: time to move on from wedge resections?

Background: A considerable proportion of intended pulmonary metastasectomies is known to turn out as new incidental primary lung cancers in final pathology. We aimed to analyse the trends and results of pulmonary metastasectomies using the intention-to-treat approach with an emphasis on final histopathological findings. Methods: All intention-to-treat pulmonary metastasectomies performed in Oulu University Hospital between 2000 and 2020 were included in the study. Long term survival was analysed with the Kaplan-Meier method and log-rank tests. A binary logistic regression analysis was performed to calculate odds ratios for incidental primary lung cancer in final histology. Results: A total of 154 intended pulmonary metastasectomies were performed to 127 individual patients. There was an increasing trend in pulmonary metastasectomies during the study period. Despite the increasing trend in comorbidities of the operated patients, the length of hospital stays decreased, and the postoperative complication rates remained stable. In final pathology reports, 9.7% were new primary lung cancers and 13.0% were benign nodules. A long disease-free interval (≥24 months) and smoking history were associated with incidental primary lung cancer in final histology. The short-term 30- and 90-day mortalities after pulmonary metastasectomy were 0.7%. The 5-year survival after pulmonary metastasectomy from all histologies was 52.8%, and from colorectal cancer metastasectomies (n=34) it was 73.5%. Conclusions: The significant amount of new primary lung cancer lesions in pulmonary metastasectomy specimens highlight the diagnostic importance of pulmonary metastasectomy. A segmentectomy could be considered as a primary procedure in pulmonary metastasectomy in patients with a long disease-free interval and a heavy smoking history.

Tertiary lymphoid structures in pulmonary metastases of microsatellite stable colorectal cancer.

Tertiary lymphoid structures (TLSs) are ectopic lymphoid aggregates located at sites of chronic inflammation and recognized as prognosticators in several cancers. We aimed to analyse the prognostic effect of TLSs in colorectal cancer (CRC) pulmonary metastases and primary tumours, with a comparison to the CD3+ and CD8+ cell density-based immune cell score (ICS). For TLS density and TLS maximum diameter analysis, 67 pulmonary metastases and 63 primary tumours were stained with haematoxylin and eosin. For ICS scoring and analysis, CD3 and CD8 immunohistochemistry was performed. Excellent interobserver agreement was achieved in all TLS measurements. Of all patients, 36 patients had low TLS density (< 0.222 follicles/mm) and 31 patients had high TLS density (≥ 0.222 follicles/mm) in the first resected pulmonary metastases. TLS density (adjusted HR 0.91, 0.48-1.73) or maximum diameter (adjusted HR 0.78, 0.40-1.51) did not have prognostic value in pulmonary metastases. In primary tumours, higher TLS density (adjusted HR 0.39, 0.18-0.87) and maximum diameter (adjusted HR 0.28, 0.11-0.73) were associated with lower mortality. In the pulmonary metastases, ICS had superior prognostic value to TLSs; however, TLSs and ICS were significantly associated. In conclusion, TLSs in CRC pulmonary metastases had no prognostic value but correlated with the ICS. TLSs in primary tumours associated with favourable prognosis.

The prognostic role of tumor budding and tumor-stroma ratio in pulmonary metastasis of colorectal carcinoma.

OBJECTIVE: To evaluate the prognostic value of tumor budding and tumor-stroma ratio (TSR) in resected pulmonary metastases of colorectal carcinoma (CRC). METHODS: In total, 106 pulmonary metastasectomies were performed to 74 patients in two study hospitals during 2000-2020. All relevant clinical data were retrospectively collected. Tumor budding based on the International Tumor Budding Consensus Conference recommendations and TSR in the first resected pulmonary metastases and primary tumors were evaluated from diagnostic hematoxylin-eosin-stained histopathological slides. RESULTS: 60 patients (85.7%) had low tumor budding (≤5 buds/field) and 10 patients (14.3%) had high tumor budding (>5 buds/field) in their first pulmonary metastases of CRC. 5-year overall survival rates of pulmonary metastasectomy in low and high total tumor budding were 28.3% and 37.3% (p = 0.387), respectively. 19 patients (27.1%) had low TSR and 51 patients (72.9%) had high TSR. The 5-year overall survival rates were 32.9% in low and 28.6% in high TSR of first pulmonary metastases (p = 0.746). Tumor budding and TSR did not provide prognostic value in Cox multivariate analysis. Tumor budding and TSR in resected pulmonary metastases were not associated with those of the primary tumor. CONCLUSION: Tumor budding and TSR in the resected pulmonary metastases of CRC showed no statistically significant prognostic value, however, additional well-powered confirmatory studies are needed.

Increasing Use of PET-CT, Neoadjuvant Treatment, Minimally Invasive Approach and Surgical Radicality in Esophageal Cancer Surgery are Associated with Improved Short- and Long-term Outcomes in Real-World Setting.

BACKGROUND: Guideline adherence has improved outcomes in several cancers. Our aim was to evaluate whether the rate of PET-CT, neoadjuvant treatment, minimally invasive approach, and surgical radicality, suggested also by recent guidelines, would improve short- and long-term operative outcomes in esophageal cancer in real-world setting. METHODS: This retrospective study in two Finnish Hospitals between 2010 and 2020 included 296 esophageal cancer patients. Grouping factors based on four factors with annual cut-offs by center were 90% rate in PET-CT-based staging, 70% in neoadjuvant therapy usage, 80% in minimally invasive approach, and 20 in annual mean lymph node yield. If none of factors were reached, all patients operated in that year were classified into group 1. With one to three cut-offs reached, grouping was into group 2. If all annual cut-offs were reached, patients were classified into group 3. Primary end points were major complication rate and overall 1-, 3-, and 5-year survival. RESULTS: Major complication rate decreased significantly from 38.2% in group 1 (p < 0.001) and 34.2% in group 2 (p < 0.001) to 10.2% in group 3. Overall 1-, 3-, and 5-year survival rates between groups 1-3 were 77.9% vs. 80.3% vs. 94.2% (p = 0.004), 51.5% vs. 51.1% vs. 67.3% (p = 0.022), and 44.1% vs. 47.4% vs. 55.5% (p = 0.065), respectively. Adjusted 5-year overall mortality was reduced significantly in group 3 compared to group 1 (HR 0.46, 95% CI 0.28-0.75). CONCLUSION: This study suggests that increasing rate of PET-CT, neoadjuvant treatment, minimally invasive surgery, and surgical radicality improves short- and long-term outcomes in operated esophageal cancer patients.

CD3+ and CD8+ T-Cell-Based Immune Cell Score and PD-(L)1 Expression in Pulmonary Metastases of Microsatellite Stable Colorectal Cancer.

The objective of this study was to evaluate the prognostic value of CD3+ and CD8+ based immune cell score (ICS), programmed death -1 (PD-1) and programmed death ligand -1 (PD-L1) in pulmonary metastases of proficient mismatch repair colorectal cancer (CRC) patients. A total of 101 pulmonary metastases and 62 primary CRC tumours were stained for CD3+, CD8+, PD-1 and PD-L1 expression. The prognostic value of ICS, PD-1/PD-L1 expression in 67 first pulmonary metastases and 61 primary CRC tumour was analysed. Comparative analysis was also performed between primary tumours and pulmonary metastases, as well as between T-cell densities and PD-1/PD-L1 expression. The 5-year overall survival rates of low, intermediate, and high ICS in pulmonary metastases were 10.0%, 25.5% and 47.0% (p = 0.046), respectively. Patients with high vs. low ICS in pulmonary metastases had a significantly better 5-year survival (adjusted HR 0.25, 95% CI 0.09-0.75, p = 0.013). High tumour cell PD-L1 expression in the pulmonary metastases was associated with improved survival (p = 0.024). Primary tumour CD8+ expression was significantly correlated with all T-cell densities in pulmonary metastases. Conclusion: The ICS evaluated from the resected pulmonary metastases of CRC showed significant prognostic value. High PD-L1 expression in pulmonary metastases is associated with favourable prognosis.

Late incidence and recurrence of new-onset atrial fibrillation after isolated surgical aortic valve replacement.

OBJECTIVES: Atrial fibrillation (AF) is a common complication after cardiac surgery. More knowledge is needed about long-term AF recurrence and adverse outcomes related to new-onset AF (NOAF) during the index hospitalization. METHODS: A total of 1073 patients underwent isolated surgical aortic valve replacement at the 4 participating hospitals (2002-2014). After the exclusion of patients with a history of any preoperative AF, the final study population included 529 patients in the bioprosthetic and 253 patients in the mechanical valve prosthesis cohort. Median follow-up time was 5.4 (interquartile range, 3.4-8.2) years in the combined cohort. RESULTS: Altogether 333 (42.6%) patients had in-hospital NOAF and 250 (32.0%) AF after hospital discharge. In the mechanical cohort, 64 (25.3%) experienced in-hospital NOAF and 74 (29.2%) AF after hospital discharge, whereas in the bioprosthetic cohort, 269 (50.9%) patients had in-hospital NOAF and 176 (33.3%) AF after hospital discharge. Patients with NOAF during the index hospital stay had a multifold risk of AF after hospital discharge in the combined cohort (hazard ratio [HR], 3.68; 95% confidence interval [CI], 2.82-4.81; P < .0001) as well as in both cohorts separately (bioprosthetic: HR, 4.35; 95% CI, 3.05-6.22; P < .001; mechanical: HR, 2.54; 95% CI, 1.59-4.03; P < .001). Patients with an in-hospital NOAF also had a significantly higher adjusted risk of death during the follow-up in the mechanical (HR, 2.05; 95% CI, 1.10-3.82; P = .025) and bioprosthetic (HR, 1.63; 95% CI, 1.17-2.28; P = .004) valve prosthesis cohorts. CONCLUSIONS: NOAF during the index hospitalization is associated with a 2- to 4-fold risk of later AF and 1.6- to 2.0-fold risk of all-cause mortality after mechanical and bioprosthetic surgical aortic valve replacement.

Thirty years of esophageal cancer surgery in Oulu University Hospital.

BACKGROUND: Esophagectomy is the mainstay of surgical treatment of esophageal cancer, but involves high operative risk. The aim of this study was to review the evolution surgical treatment of esophageal cancer in Northern Finland, with introduction of minimally invasive techniques. METHODS: All elective esophagectomies performed in Oulu University Hospital between years 1987 and 2020 were included. Treatment strategies were compared to current guidelines including staging and use of neoadjuvant therapy, and benchmark values including postoperative morbidity, hospital stay, readmissions and 90-day mortality. Long-term survival was compared to previous national studies. RESULTS: Between years 1987 and 2020 a total of 341 underwent an esophagectomy. Transhiatal resection was performed to 167 (49.3%), Ivor Lewis to 129 (38.1%) and McKeown to 42 (12.4%) patients. MIE was performed to 49 (14.5%) patients. During the past four years 83.7% of locally advanced diseases received neoadjuvant treatment. Since 1987, gradual improvements have occurred especially in incidence of pleural effusion requiring additional drainage procedure (highest in 2011-2013 and in last four years 14.0%), recurrent nerve injuries (highest in 2008-2010 29.4% and lowest in 2017-2020 1.8%) and in 1-year survival rate (1987-1998 68.4% vs. 2017-2020 82.1%). No major changes in comorbidity, complication rate, anastomosis leaks, hospital stay or postoperative mortality were seen. CONCLUSIONS: Esophageal cancer surgery has gone through major changes over three decades. Current guideline-based treatment has resulted with progressive improvement in mid- and long-term survival. However, despite modern protocol, no major improvement has occurred for example in major complications, anastomosis leak rates or hospital stay.

Minimally invasive esophagectomy learning curves with different types of background experience.

BACKGROUND: Minimally invasive esophagectomy (MIE) is a complex procedure with learning associated morbidity. The aim was to evaluate the learning curve for MIE focusing on short-term outcomes in two settings: (I) experienced MIE surgeon in new hospital (Hospital 1); (II) surgeons experienced with open esophagectomy and minimally invasive surrogate surgery (Hospital 2). METHODS: In Hospital 1 and Hospital 2, on intent-to-treat basis number of MIEs were 132 and 57, respectively. The primary outcomes were major complications and anastomosis leaks. Secondary outcomes were operative time, blood loss, lymph node yield, hospital stay and 1-year mortality. Length of learning curves were analyzed with risk-adjusted cumulative sum (RA-CUSUM) method. RESULTS: In Hospital 1, major complication and anastomosis leak rates were 9.8% and 4.5%, 22.8% and 12.3% in Hospital 2, respectively. In Hospital 1, complication and leak rates remained stable. In Hospital 2, improvement occurred after 34 cases in major complications and 29 cases in leaks. Of secondary outcomes, improvements were seen in Hospital 1 in operative time after 61, blood loss after 86, lymph node yield after 52, hospital stay after 19 and 1-year mortality after 24 cases. In Hospital 2, improvement occurred in operative time after 30, blood loss after 15, lymph node yield after 45, hospital stay after 50 and 1-year mortality after 15 cases. CONCLUSIONS: According to this study, learning phase of the individual surgeon determines the outcomes of MIE, not the institutional learning phase.

Indications and predictors for pacemaker implantation after isolated aortic valve replacement with bioprostheses: the CAREAVR study.

OBJECTIVES: We sought to study the indications, long-term occurrence, and predictors of permanent pacemaker implantation (PPI) after isolated surgical aortic valve replacement with bioprostheses. METHODS: The CAREAVR study included 704 patients (385 females, 54.7%) without a preoperative PPI (mean ± standard deviation age 75 ± 7 years) undergoing isolated surgical aortic valve replacement at 4 Finnish hospitals between 2002 and 2014. Data were extracted from electronic patient records. RESULTS: The follow-up was median 4.7 years (range 1 day to 12.3 years). Altogether 56 patients received PPI postoperatively, with the median 507 days from the operation (range 6 days to 10.0 years). The PPI indications were atrioventricular block (31 patients, 55%) and sick sinus syndrome (21 patients, 37.5%). For 4 patients, the PPI indication remained unknown. A competing risks regression analysis (Fine-Gray method), adjusted with age, sex, diabetes, coronary artery disease, preoperative atrial fibrillation (AF), left ventricular ejection fraction, New York Heart Association class, AF at discharge and urgency of operation, was used to assess risk factors for PPI. Only AF at discharge (subdistribution hazard ratio 4.34, 95% confidence interval 2.34-8.03) was a predictor for a PPI. CONCLUSIONS: Though atrioventricular block is the major indication for PPI after surgical aortic valve replacement, >30% of PPIs are implanted due to sick sinus syndrome during both short-term follow-up and long-term follow-up. Postoperative AF versus sinus rhythm conveys >4-fold risk of PPI. CLINICAL TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT02626871.

Remote ischaemic preconditioning may prolong permissible period of hypothermic circulatory arrest in a porcine model.

Objectives. The hypothermic circulatory arrest (HCA) is still of paramount importance in aortic arch surgery, but the safe period of the arrest is limited. Remote ischaemic preconditioning (RIPC) prepares the cerebral tissue for ischaemic insult. Prolongation of the permissible period of HCA with RIPC may have a major impact on the outcome of aortic operations requiring cessation of blood flow by decreasing the rate of neurological deficits. Design. Twenty pigs were randomised into the RIPC group (n = 10) and the control group (n = 10). The RIPC group underwent four cycles of transient hind limb ischaemia. Both groups underwent cooling with cardiopulmonary bypass to 11 °C followed by a 45-minute HCA and re-warming to 36 °C. Cerebral blood flow was measured with a transit time ultrasonic flowmeter from the right common carotid artery, and the arteriovenous oxygen difference was calculated from sagittal sinus and arterial blood samples. Measurements were taken at several time points during cooling and warming. Temperature coefficient (Q10) was calculated to determine estimated permissible periods of HCA. Results. The Q10 was 2.27 (1.98-2.58) for the RIPC group and 1.87 (1.61-2.25) for the control group. The permissible period of HCA at 18 °C was 26 minutes (20-33) in the RIPC group and 17 minutes (13-25) in the control group (p = .063)(Data expressed in medians and interquartile ranges). Conclusions. RIPC tends to suppress cerebral metabolism during cooling with cardiopulmonary bypass and may prolong estimated permissible period of HCA.

Safety of direct true lumen cannulation after venous exsanguination: a study in a surviving porcine model†.

OBJECTIVES: Type A aortic dissection requires immediate surgery. Traditional cannulation methods such as the central aortic cannulation with the Seldinger technique and axillary cannulation are primary choices. Yet in the presence of tamponade or severe cardiogenic shock, these can be too time-consuming to complete. Direct true lumen cannulation after venous exsanguination not only avoids this issue but also leads to transient global ischaemia. We studied the safety of direct true lumen cannulation from the aspect of global ischaemia in a surviving porcine model. METHODS: Twelve pigs were randomized to either control or intervention groups (6 + 6). The intervention group underwent simulated direct true lumen cannulation by exsanguination and circulatory arrest for 5 min at 35°C before cardiopulmonary bypass (CPB). Both groups underwent CPB cooling to 25°C followed by a 25-min arrest period and subsequent warming to 36°C. Neuron-specific enolase levels were measured at 6 time-points from blood samples. Near-infrared spectroscopy was used to determine brain oxygenation. The neurological recovery was evaluated daily during a 7-day follow-up, and the brain was harvested for a histopathological analysis after euthanization. RESULTS: All pigs recovered their normal neurological behaviour. The neurobehavioural total score on postoperative day 2 reached borderline statistical significance, thus favouring the intervention group [(9 (8.75-9) vs 6.5 (5.5-9), P = 0.06]. Near-infrared spectroscopy values and neuron-specific enolase levels slightly favoured the control group during the cooling period, but the difference was not clinically significant. The histopathological analysis showed no difference between the groups. CONCLUSIONS: A 5-min period of normothermic global ischaemia before CPB does not impair the neurological outcome following hypothermic circulatory arrest in a surviving porcine model.

Performance of CHA2DS2-VASc score for stroke prediction after surgical aortic valve replacement.

OBJECTIVE: Stroke is a frequent complication occurring early and late after surgical aortic valve replacement. There is an unmet clinical need for simple tools to assess postoperative stroke risk. We sought to assess the predictive performance of Congestive heart failure; Hypertension; Age ≥75 (doubled); Diabetes mellitus; prior Stroke, transient ischemic attack or thromboembolism (doubled); Vascular disease; Age 65 to 74; Sex category (female) (CHA2DS2-VASc) score in patients undergoing surgical aortic valve replacement with a bioprosthesis. METHODS: Seven hundred fourteen patients undergoing isolated surgical aortic valve replacement with a bioprosthesis at 4 university hospitals were included. Data were collected retrospectively from patient records and monitored by an independent party. RESULTS: Median follow-up time was 4.8 years. Mean CHA2DS2-VASc score was 4.1 ± 1.6. Low (scores, 0-1), high (scores, 2-4), and very high (scores, 5-9) CHA2DS2-VASc scores were observed in 39 (5.5%), 400 (56.0%), and 262 (38.5%) patients, respectively. Incidences of stroke or transient ischemic attack at 1 year were 2.6%, 4.8%, and 10.7%; at 5 years incidences were 5.2%, 14.0%, and 21.9%; and at 10 years incidence were 5.2%, 20.7%, and 37.9% for patients in low, high, and very high scores, respectively. Incidences of major bleeds at 1 year were 0%, 1.8%, and 2.7%; at 5 years incidences were 0%, 5.4%, and 8.7%; and at 10 years incidences were 0%, 9.0%, and 27.1%, respectively. Competing risk analysis showed that patients with CHA2DS2-VASc score of 5 through 9 had a significantly increased risk of stroke or transient ischemic attack (hazard ratio, 4.75; 95% confidence interval, 1.09-20.6; P = .037) irrespective of preoperative or new-onset in-hospital atrial fibrillation compared with low-risk patients. CONCLUSIONS: CHA2DS2-VASc is a valuable tool to identify patients with increased risk of stroke and major bleeding, and for whom alternative strategies for prevention of late neurologic complications should be adopted.

Thromboembolisms related to post-operative electrical cardioversions for atrial fibrillation in patients with surgical aortic valve replacement.

Aims: Post-operative atrial fibrillation (POAF) is a frequent complication after open-heart surgery, and cardioversions (CV) are commonly performed to restore sinus rhythm. However, little data exists on thrombo-embolic risk related to early post-operative CV and on the recurrence of POAF after CV. CAREAVR study sought to assess the rate of strokes, transient ischaemic attacks (TIA), and mortality shortly after POAF-triggered CV in patients who underwent isolated surgical aortic valve replacement (SAVR) with a bioprosthesis. Methods and results: Altogether 721 patients underwent isolated SAVR with a bioprosthesis at four Finnish university hospitals. During post-operative hospitalization, after patients with prior chronic AF were excluded, 309/634 (48.7%) of patients had at least one episode of POAF [median time (interquartile range) 3 (3) days], and an electrical CV was performed in 113/309 (36.6%) of them. The length of hospital stay was not affected by CV. At 30 days follow-up, the rate of stroke, TIA or mortality was higher in those AF patients who underwent CV vs. those who did not (9.7% vs. 3.6%, P = 0.04, respectively; adjusted hazard ratio 2.63, 95% confidence interval 1.00-6.92, P = 0.05). Similar proportion of patients in both groups were in AF rhythm at discharge (32.7% vs. 35.7%, P = 0.18); and at 3 months (25.0% vs. 23.6%, P = 0.40), respectively. Conclusion: In this real-world population of patients undergoing isolated SAVR, the rate of POAF was nearly 50%. One-third of these patients underwent an electrical CV, and they exhibited over two-fold risk for thromboembolisms and mortality. Cardioversion did not affect the short-term prevalence of AF.

Exploring Spinal Cord Protection by Remote Ischemic Preconditioning: An Experimental Study.

BACKGROUND: Paraplegia is one of the most severe complications occurring after the repair of thoracic and thoracoabdominal aortic aneurysms. Remote ischemic preconditioning (RIPC) has been shown to mitigate neurologic damage, and this study assessed its efficacy in preventing spinal cord ischemia. METHODS: The study randomized 16 female pigs into an RIPC group (n = 8) and a control group (n = 8). The RIPC group underwent four cycles of 5-minute ischemia-reperfusion episodes by intermittent occlusion of the left iliac artery. All animals underwent systematic closure of the left subclavian artery and segmental arteries of the descending thoracic aorta to the level of diaphragm. Motor-evoked potential monitoring was performed in both hind limbs. Continuous electrocardiogram and hemodynamics were monitored, and pulmonary artery blood samples were collected. A neurologic assessment was performed 6 hours after the procedure. The thoracic and lumbar portions of the spinal cord were collected for histologic and immunohistochemical analysis. RESULTS: The bilateral motor-evoked potential amplitude responses were higher in the RIPC group (p < 0.05) than in the control group; the difference was detected already before spinal cord ischemia. Paraplegia occurred in 1 control animal. Immunohistochemical total scores of antioxidant response regulator nuclear factor erythroid 2-related factor 2 were better in the RIPC group (11.0; range, 8.5 to 14.0) than in the control group (5.2; range, 1.0 to 9.0; p = 0.023). CONCLUSIONS: RIPC induces electrophysiologic changes in the central nervous system that may confer spinal cord protection extending the resistance to ischemia. The significantly higher nuclear factor erythroid 2-related factor 2 scores suggest better neuronal cell protection against oxidative stress in the RIPC group.

Review of remote ischemic preconditioning: from laboratory studies to clinical trials.

In remote ischemic preconditioning (RIPC) short periods of non-lethal ischemia followed by reperfusion of tissue or organ prepare remote tissue or organ to resist a subsequent more severe ischemia-reperfusion injury. The signaling mechanism of RIPC can be humoral communication, neuronal stimulation, systemic modification of circulating immune cells, and activation of hypoxia inducible genes. Despite promising evidence from experimental studies, the clinical effects of RIPC have been controversial. Heterogeneity of inclusion and exclusion criteria and confounding factors such as comedication, anesthesia, comorbidities, and other risk factors may have influenced the efficacy of RIPC. Although the cardioprotective pathways of RIPC are more widely studied, there is also evidence of benefits in CNS, kidney and liver protection. Future research should explore the potential of RIPC, not only in cardiac protection, but also in patients with threatening ischemia of the brain, organ transplantation of the heart, liver and kidney and extensive cardiovascular surgery. RIPC is generally well-tolerated, safe, effective, and easily feasible. It has a great prospect for ischemic protection of the heart and other organs.

High number of transplanted stem cells improves myocardial recovery after AMI in a porcine model.

OBJECTIVE: The clinical data considering the bone marrow mononuclear cell (BMMNC) therapy in treatment for acute myocardial infarction (AMI) are controversial and the mechanisms remain unknown. Our objective was to study the cardiac function and changes in cytokine levels after administration of BMMNC in experimental AMI model. DESIGN: Unlabeled or Super-Paramagnetic-Iron-Oxide-labeled BMMNCs or saline was injected into myocardium of 31 pigs after circumflex artery occlusion. Ejection fraction (EF) was measured preoperatively, postoperatively and at 21 days by echocardiography. Cardiac MRI was performed postoperatively and after 21 days in 7 BMMNC animals. Serum cytokine levels were measured at baseline, 24 h and 21 days. Cellular homing was evaluated comparing MRI and histology. RESULTS: From baseline to 21 days EF decreased less in BMMNC group (EF mean control -19 SD 12 vs. BMMNC -4 SD 15 percentage points p = 0.02). Cytokine concentrations showed high variability between the animals. MRI correlated with histology in cell detection and revealed BMMNCs in the infarction area. By MRI, EF improved 11 percentage points. The improvement in EF was associated with the number of transplanted BMMNCs detected in the myocardium. CONCLUSION: BMMNC injection after AMI improved cardiac function. Quantity of transplanted BMMNCs correlated with the improvement in cardiac function after AMI.

Safety and biodistribution study of bone marrow-derived mesenchymal stromal cells and mononuclear cells and the impact of the administration route in an intact porcine model.

BACKGROUND AIMS: Bone marrow mononuclear cells (BM-MNCs) and bone marrow-derived mesenchymal stem stromal cells (BM-MSCs) could have therapeutic potential for numerous conditions, including ischemia-related injury. Cells transplanted intravascularly may become entrapped in the lungs, which potentially decreases their therapeutic effect and increases the risk for embolism. METHODS: Twelve pigs were divided into groups of 3 and received (99m)Tc- hydroxymethyl-propylene-amine-oxime-labeled autologous BM-MNCs or allogeneic BM-MSCs by either intravenous (IV) or intra-arterial (IA) transplantation. A whole body scan and single photon emission computed tomography/computed tomography (SPECT/CT) were performed 8 h later, and tissue biopsies were collected for gamma counting. A helical CT scan was also performed on 4 pigs to detect possible pulmonary embolism, 2 after IV BM-MSC injection and 2 after saline injection. RESULTS: The transplantation route had a greater impact on the biodistribution of the BM-MSCs than the BM-MNCs. The BM-MNCs accumulated in the spleen and bones, irrespective of the administration route. The BM-MSCs had relatively higher uptake in the kidneys. The IA transplantation decreased the deposition of BM-MSCs in the lungs and increased uptake in other organs, especially in the liver. Lung atelectases were frequent due to mechanical ventilation and attracted transplanted cells. CT did not reveal any pulmonary embolism. CONCLUSIONS: Both administration routes were found to be safe, but iatrogenic atelectasis might be an issue when cells accumulate in the lungs. The IA administration is effective in avoiding pulmonary entrapment of BM-MSCs. The cell type and administration method both have a major impact on the acute homing.

Leg ischaemia before circulatory arrest alters brain leucocyte count and respiratory chain redox state.

OBJECTIVES: Remote ischaemic preconditioning and its neuroprotective abilities are currently under investigation and the method has shown significant effects in several small and large animal studies. In our previous studies, leucocyte filtration during cardiopulmonary bypass reduced cerebrocortical adherent leucocyte count and mitigated cerebral damage after hypothermic circulatory arrest (HCA) in piglets. This study aimed to obtain and assess direct visual data of leucocyte behaviour in cerebral vessels after hypothermic circulatory arrest following remote ischaemic preconditioning. METHODS: Twelve native stock piglets were randomized into a remote ischaemic preconditioning group (n = 6) and a control group (n = 6). The intervention group underwent hind-leg ischaemia, whereas the control group received a sham-treatment before a 60-min period of hypothermic circulatory arrest. An intravital microscope was used to obtain measurements from the cerebrocortical vessel in vivo. It included three sets of filters: a violet filter to visualize microvascular perfusion and vessel diameter, a green filter for visualization of rhodamine-labelled leucocytes and an ultraviolet filter for reduced nicotinamide adenine dinucleotide (NADH) analysis. The final magnification on the microscope was 400. After the experiment, cerebral and cerebellar biopsies were collected and analysed with transmission electron microscope by a blinded analyst. RESULTS: In the transmission electron microscope analysis, the entire intervention group had normal, unaffected rough endoplasmic reticulum's in their cerebellar tissue, whereas the control group had a mean score of 1.06 (standard deviation 0.41) (P = 0.026). The measured amount of adherent leucocytes was lower in the remote ischaemic preconditioning group. The difference was statistically significant at 5, 15 and 45 min after circulatory arrest. Statistically significant differences were seen also in the recovery phase at 90 and 120 min after reperfusion. Nicotinamide adenine dinucleotide autofluorescence had statistically significant differences at 10 min after cooling and at 120 and 180 min after hypothermic circulatory arrest. CONCLUSIONS: Remote ischaemic preconditioning seems to provide better mitochondrial respiratory chain function as indicated by the higher NADH content. It simultaneously provides a reduction of adherent leucocytes in cerebral vessels after hypothermic circulatory arrest. Additionally, it might provide some degree of cellular organ preservation as implied by the electron microscopy results.