Cardioprotection by remote ischemic conditioning is transferable by plasma and mediated by exosomes

Background

Remote ischemic conditioning (RIC) by brief periods of limb ischemia and reperfusion protects against ischemia-reperfusion injury. However, the mechanism is unknown.

Purpose

We studied the role of exosomes for mediating the cardioprotective signal and whether they accumulate in injured myocardium.

Methods

Blood samples from 12 healthy male volunteers were obtained prior to and one hour after RIC. Plasma obtained before and after RIC (n=4) (P-Pre and P-Post) was used to evaluate the transferability of RIC. Pre- and Post-RIC plasma (n=8) was separated into an exosome rich fraction (Exo-Pre and Exo-Post) and an exosome depleted fraction (Prot-Pre and Prot-Post) by size exclusion chromatography. All studies were carried out in duplicate samples from each volunteer. Infarct size was compared in Sprague-Dawley rat hearts perfused with plasma, exosomes and exosome depleted fractions in a Langendorff model. We investigated changes in the miRNA content of the exosomes after RIC by a human miRNA panel. Additionally, fluorescently labeled exosomes isolated from C2C12 cells were used to assess accumulation in injured myocardium in an in vivo rat model. Rats were divided into an infarct group (n=6) (left anterior descending artery ligation) and a sham group (n=6) (without ligation). Labelled exosomes were injected in the femoral vein prior to reperfusion. Exosome-accumulation in infarcted or sham myocardium was evaluated.

Results

P-Post reduced infarct size by 15% points compared with P-Pre (55±4% vs 70±6%, p=0.03) (Fig. 1a). Exo-Post reduced infarct size by 16% points compared with Exo-Pre (53±15% vs 68±12%, p=0.03) (Fig. 1b). Prot-Post did not affect infarct size compared to Prot-Pre (64±3% and 68±10%, p>0.99). We found miRNA-16, miRNA-144 and miRNA-451 to be upregulated in exosomes after RIC and the mTOR-pathway as a potential target for these miRNAs. In the in vivo model, labelled exosomes accumulated more intensively in the infarct area than in remote areas and sham hearts (Fig. 1c).

Conclusion

Cardioprotection by RIC is mediated by exosomes with a changed miRNA profile and exosomes accumulate in injured myocardium.

Figure 1

Funding Acknowledgement

Type of funding source: Private company. Main funding source(s): Novo synergy

Local recurrence rate in a national Danish patient cohort after curative treatment for rectal cancer

AIM

Several trials have shown that preoperative (chemo)radiotherapy (CRT) reduces local recurrence rates (LRRs) in rectal cancer (RC). The use of CRT varies greatly between countries. It is unknown whether the restrictive use of CRT in Denmark results in a higher LRR relative to other countries. The aim was to evaluate the LRR in a national Danish consecutive cohort of patients with RC.

METHODS

All data from patients with RC in Denmark in 2009-2010 who were operated on with curative intent were retrieved from the Danish Colorectal Cancer Group database. Patients with metastases at the time of diagnosis, patients with synchronous colon cancer, and patients, in whom only local surgical procedures were performed, were excluded. In total, 1633 patients met the inclusion criteria. Clinical follow-up was at least five years with a cut-off date of 31 December 2015.

RESULTS

Clinical follow-up was 5.4 years (median) with an interquartile range of 4.5-6.1 years. Of all included patients, 479 (29%) were treated with preoperative long-course CRT. Local recurrence was found in 68 patients, resulting in an LRR of 4.2%, and 182 (11%) patients developed distant metastases. Five-year overall survival was 74% (95% CI: 71.64-75.91).

CONCLUSIONS

Five-year follow-up of curatively treated patients with RC in Denmark revealed a low LRR. This figure is identical to those reported in other Nordic countries, despite Denmark's considerably stricter guidelines for CRT. The obtained results justify the currently adopted restrictive use of preoperative CRT in Denmark.

Colo-Colonic Intussusception Caused by Lipoma

Intussusception is primarily seen among children, most often as idiopathic ileocolic intussusception (1, 4), and only 5 to 16% of all intussusceptions are seen in adults (1, 8). In contrast to childhood invagination, in adults underlying pathologic processes are identified in 18 to 90% (1, 8).

This report presents 2 cases of colo-colonic intussusception caused by a colonic lipoma. The ultrasonic features of this benign tumour are rather characteristic. A definitive diagnosis can be provided by CT.

Colo-colonic intussusception caused by lipoma. Case reports

Intussusception is primarily seen among children, most often as idiopathic ileocolic intussusception (1, 4), and only 5 to 16% of all intussusceptions are seen in adults (1, 8). In contrast to childhood invagination, in adults underlying pathologic processes are identified in 18 to 90% (1, 8). This report presents 2 cases of colo-colonic intussusception caused by a colonic lipoma. The ultrasonic features of this benign tumour are rather characteristic. A definitive diagnosis can be provided by CT.

Colo-colonic intussusception caused by lipoma. Case reports

Intussusception is primarily seen among children, most often as idiopathic ileocolic intussusception (1, 4), and only 5 to 16% of all intussusceptions are seen in adults (1, 8). In contrast to childhood invagination, in adults underlying pathologic processes are identified in 18 to 90% (1, 8). This report presents 2 cases of colo-colonic intussusception caused by a colonic lipoma. The ultrasonic features of this benign tumour are rather characteristic. A definitive diagnosis can be provided by CT.

Thyroid volume and morphology and urinary iodine excretion in a Danish municipality

In order to throw light upon the eventual need for iodine supplementation in Denmark, four age groups of women (15, 30, 45 and 60 years) from the Holbaek municipality were invited for a clinical and ultrasound study of thyroid volume, structure and function. Of the 570 women invited, 391 accepted and were divided into the following groups: group I: 15 years, N = 113; group II: 30 years, N = 100; group III: 45 years, N = 98; group IV: 60 years, N = 80. The results were as follows the thyroid gland was palpable in 39% and visible in 16% of the entire group; 19% had a family history of thyroid disorders and 7.6% had a previous thyroid disorder. Thyroid volumes (median (range)) as measured by ultrasound were 12 ml (4-29 ml), 18 ml (5-47 ml), 18 ml (7-64 ml) and 18 ml (9-51 ml) in groups I-IV, respectively. The calculated 24-h iodine excretion was 65 micrograms (19-365 micrograms), 88 micrograms (15-274 micrograms), 97 micrograms (40-737 micrograms) and 83 micrograms (50-999 micrograms) in groups I-IV, respectively. An abnormal echo structure was present in 3, 10, 21 and 30%, respectively. Defining a goitre as a thyroid volume above 28 ml indicated a goitre prevalence of 17% in females aged 30-60 years in the Holbaek area of Denmark. Among the 60-year-old women, 3% had a clinically significant goitre (WHO grade III). Thyroid volume did not correlate with iodine excretion. The benefit of iodine supplementation is discussed.