Release of pig leukocytes and reduced human NK cell recruitment during ex vivo perfusion of HLA‐E/human CD46 double‐transgenic pig limbs with human blood

Background

In pig‐to‐human xenotransplantation, interactions between human natural killer (NK) cells and porcine endothelial cells (pEC) are characterized by recruitment and cytotoxicity. Protection from xenogeneic NK cytotoxicity can be achieved in vitro by the expression of the non‐classical human leukocyte antigen‐E (HLA‐E) on pEC. Thus, the aim of this study was to analyze NK cell responses to vascularized xenografts using an ex vivo perfusion system of pig limbs with human blood.

Methods

Six pig forelimbs per group, respectively, stemming from either wild‐type (wt) or HLA‐E/hCD46 double‐transgenic (tg) animals, were perfused ex vivo with heparinized human blood for 12 hours. Blood samples were collected at defined time intervals, cell numbers counted, and peripheral blood mononuclear cells analyzed for phenotype by flow cytometry. Muscle biopsies were analyzed for NK cell infiltration. In vitro NK cytotoxicity assays were performed using pEC derived from wt and tg animals as target cells.

Results

Ex vivo, a strong reduction in circulating human CD45 leukocytes was observed after 60 minutes of xenoperfusion in both wt and tg limb groups. NK cell numbers dropped significantly. Within the first 10 minutes, the decrease in NK cells was more significant in the wt limb perfusions as compared to tg limbs. Immunohistology of biopsies taken after 12 hours showed less NK cell tissue infiltration in the tg limbs. In vitro, NK cytotoxicity against hCD46 single tg pEC and wt pEC was similar, while lysis of double tg HLA‐E/hCD46 pEC was significantly reduced. Finally, circulating cells of pig origin were observed during the ex vivo xenoperfusions. These cells expressed phenotypes mainly of monocytes, B and T lymphocytes, NK cells, as well as some activated endothelial cells.

Conclusions

Ex vivo perfusion of pig forelimbs using whole human blood represents a powerful tool to study humoral and early cell‐mediated rejection mechanisms of vascularized pig‐to‐human xenotransplantation, although there are several limitations of the model. Here, we show that (i) transgenic expression of HLA‐E/hCD46 in pig limbs provides partial protection from human NK cell‐mediated xeno responses and (ii) the emergence of a pig cell population during xenoperfusions with implications for the immunogenicity of xenografts.     

Comparison of Somatostatin Receptor 2-Targeting PET Tracers in the Detection of Mouse Atherosclerotic Plaques

Purpose

Rupture-prone atherosclerotic plaques are characterized by accumulation of macrophages, which have shown to express somatostatin type 2 receptors. We aimed to investigate whether somatostatin receptor-targeting positron emission tomography (PET) tracers, [⁶⁸Ga]DOTANOC, [¹⁸F]FDR-NOC, and [⁶⁸Ga]DOTATATE, can detect inflamed atherosclerotic plaques.

Procedures

Atherosclerotic IGF-II/LDLR^?/?ApoB^100/100 mice were studied in vivo and ex vivo for tracer uptake into atherosclerotic plaques. Furthermore, [⁶⁸Ga]DOTANOC and [⁶⁸Ga]DOTATATE were compared in a head-to-head setting for in vivo PET/X-ray computed tomography (CT) imaging characteristics.

Results

Ex vivo uptake of [⁶⁸Ga]DOTANOC and [⁶⁸Ga]DOTATATE in the aorta was higher in atherosclerotic mice compared to control C57Bl/6N mice, while the aortic uptake of [¹⁸F]FDR-NOC showed no genotype difference. Unlike [¹⁸F]FDR-NOC, [⁶⁸Ga]DOTANOC and [⁶⁸Ga]DOTATATE showed preferential binding to atherosclerotic plaques with plaque-to-wall ratio of 1.7?±?0.3 and 2.1?±?0.5, respectively. However, the aortic uptake and aorta-to-blood ratio of [⁶⁸Ga]DOTANOC were higher compared to [⁶⁸Ga]DOTATATE in in vivo PET/CT imaging.

Conclusion

Our results demonstrate superior applicability for [⁶⁸Ga]DOTANOC and [⁶⁸Ga]DOTATATE in the detection of atherosclerotic plaques compared to [¹⁸F]FDR-NOC.

     

Strength training can be enjoyable and beneficial for adults with cerebral palsy

Purpose: To explore the positive and negative perceptions of participating in a strength- training programme for adults with cerebral palsy.

Method: Ten adults aged over 40 years with cerebral palsy participated in a group-based 10-week progressive resistance strength-training programme in a community gymnasium. After the programme, each participant was interviewed using an in-depth semi-structured format and the results coded thematically.

Results: Participants perceived that their strength, and ability to perform everyday activities had improved. However, the main benefit for participants was enjoyment and social interaction. The only negative perceptions related to fatigue, short-term muscle soreness and a feeling that they had not improved as much as they had expected.

Conclusions: Enjoyment, a factor that can promote adherence and sustainability, was a key benefit of this strength-training programme for adults with cerebral palsy that led to perceptions of increased strength and physical functioning. These findings suggest that exercise programmes for adults with cerebral palsy should be conducted in a group in the community, thereby promoting community inclusion. In addition, it is important to provide education to participants about the normal responses and expectations of an exercise programme.     

Heart valve disease in women in the reproductive age

About 1% of pregnant women have concomitant cardiac disease. An understanding of the impact of the physiologic changes associated with pregnancy upon structural cardiac disease is essential for proper counseling and management of these complex patients, which should be treated in a specialized team with experience in congenital as well adult disease. The availability of echocardiography provides information about disease aetiology, accurate and non invasive assessment of severity and means of monitoring progression. Contraindication for pregnancies still remain severe pulmonary artery hypertension and Eisenmenger-syndrome and severe surgical non corrected cyanotic disease as well. Postrheumatic stenosis, even when previously asymptomatic, can lead to pulmonary edema. Although pregnancies with asymptomatic regurgitant lesions are better tolerated. The best procedure in severe aortic insufficiency still remains controversial. Patients with Marfan syndrome and aortic root dilatation are at risk for aortic dissection and are difficult to manage. In patients with artificial valves continuing anticoagulation with warfarin is proposed in Europe. Due to accelerated valve deterioration during pregnancy the use of bioprotheses in women who need valvular heart surgery before pregnancy necessitate later valve replacement again and perhaps an autograft or homograft could be an alternate approach. Bacterial endocarditis in pregnancy shows a low incidence and is often associated with prior history of rheumatic or congenital heart disease. Therefore prophylaxis is recommended. There is an increase in the incidence of congenital heart disease among the offsprings of affected parents. Fetal echocardiography, in combination with a multidisciplinary postnatal approach, can be used in the successful treatment of severe form of congenital heart disease.     

Posttraumatic nightmares and psychopathology in children after road traffic accidents

Posttraumatic nightmares are considered as a reexperiencing symptom of the DSM‐IV posttraumatic stress disorder (PTSD) diagnosis. Different types of posttraumatic nightmares, however, may differ in their relation to psychopathology. Thirty‐two children were longitudinally assessed 10 days, 2 months, and 6 months after traffic accidents. Occurrence and characteristics of nightmares were examined and their relation to psychopathology assessed. Thirty‐four percent of children reported posttraumatic nightmares during at least one assessment. Exact replicative nightmares at baseline assessment predicted PTSD symptoms 2 and 6 months postaccident, but not depressive symptoms. Exact replicative nightmares revealed the strongest cross‐sectional association with trauma‐specific psychopathology but not with depression. The authors conclude that posttraumatic nightmares—especially exact replicative ones—may be closely related to psychopathological mechanisms of posttraumatic stress in children.