Fluorescent Imaging of Antigen Released by a Skin-Invading Helminth Reveals Differential Uptake and Activation Profiles by Antigen Presenting Cells

Infection of the mammalian host by the parasitic helminth Schistosoma mansoni is accompanied by the release of excretory/secretory molecules (ES) from cercariae which aid penetration of the skin. These ES molecules are potent stimulants of innate immune cells leading to activation of acquired immunity. At present however, it is not known which cells take up parasite antigen, nor its intracellular fate. Here, we develop a technique to label live infectious cercariae which permits the imaging of released antigens into macrophages (MΦ) and dendritic cells (DCs) both in vitro and in vivo. The amine reactive tracer CFDA-SE was used to efficiently label the acetabular gland contents of cercariae which are released upon skin penetration. These ES products, termed ‘0-3hRP’, were phagocytosed by MHC-II+ cells in a Ca+ and actin-dependent manner. Imaging of a labelled cercaria as it penetrates the host skin over 2 hours reveals the progressive release of ES material. Recovery of cells from the skin shows that CFDA-SE labelled ES was initially (3 hrs) taken up by Gr1+MHC-II− neutrophils, followed (24 hrs) by skin-derived F4/80+MHC-IIlo MΦ and CD11c+ MHC-IIhi DC. Subsequently (48 hrs), MΦ and DC positive for CFDA-SE were detected in the skin-draining lymph nodes reflecting the time taken for antigen-laden cells to reach sites of immune priming. Comparison of in vitro-derived MΦ and DC revealed that MΦ were slower to process 0-3hRP, released higher quantities of IL-10, and expressed a greater quantity of arginase-1 transcript. Combined, our observations on differential uptake of cercarial ES by MΦ and DC suggest the development of a dynamic but ultimately balanced response that can be potentially pushed towards immune priming (via DC) or immune regulation (via MΦ)

The Mannose Receptor (CD206) is an important pattern recognition receptor (PRR) in the detection of the infective stage of the helminth Schistosoma mansoni and modulates IFNγ production.

In this study, infective larvae of the parasitic helminth Schistosoma mansoni were shown to contain a large number of glycosylated components specific for the Mannose Receptor (MR; CD206), which is an important pattern recognition receptor (PRR) of the innate immune system. MR ligands were particularly rich in excretory/secretory (E/S) material released during transformation of cercariae into schistosomula, a process critical for infection of the host. E/S material from carboxyfluorescein diacetate succinimidyl ester (CFDA-SE)-labelled cercariae showed enhanced binding by cells lines that over-express the MR. Conversely, uptake was significantly lower by bone marrow-derived macrophages (MΦ) from MR(-/-) mice, although they were more active as judged by enhanced pro-inflammatory cytokine production and CD40 expression. After natural percutaneous infection of MR(-/-) mice with CFDA-SE-labelled parasites, there were fewer cells in the skin and draining lymph nodes that were CFDA-SE(+) compared with wild-type mice, implying reduced uptake and presentation of larval parasite antigen. However, antigen-specific proliferation of skin draining lymph node cells was significantly enhanced and they secreted markedly elevated levels of IFNγ but decreased levels of IL-4. In conclusion, we show that the MR on mononuclear phagocytic cells, which are plentiful in the skin, plays a significant role in internalising E/S material released by the invasive stages of the parasite which in turn modulates their production of pro-inflammatory cytokines. In the absence of the MR, antigen-specific CD4(+) cells are Th1 biased, suggesting that ligation of the MR by glycosylated E/S material released by schistosome larvae modulates the production of CD4(+) cell specific IFNγ

Case Reports1. A Late Presentation of Loeys-Dietz Syndrome: Beware of TGFβ Receptor Mutations in Benign Joint Hypermobility

Background: Thoracic aortic aneurysms (TAA) and dissections are not uncommon causes of sudden death in young adults. Loeys-Dietz syndrome (LDS) is a rare, recently described, autosomal dominant, connective tissue disease characterized by aggressive arterial aneurysms, resulting from mutations in the transforming growth factor beta (TGFβ) receptor genes TGFBR1 and TGFBR2. Mean age at death is 26.1 years, most often due to aortic dissection. We report an unusually late presentation of LDS, diagnosed following elective surgery in a female with a long history of joint hypermobility. Methods: A 51-year-old Caucasian lady complained of chest pain and headache following a dural leak from spinal anaesthesia for an elective ankle arthroscopy. CT scan and echocardiography demonstrated a dilated aortic root and significant aortic regurgitation. MRA demonstrated aortic tortuosity, an infrarenal aortic aneurysm and aneurysms in the left renal and right internal mammary arteries. She underwent aortic root repair and aortic valve replacement. She had a background of long-standing joint pains secondary to hypermobility, easy bruising, unusual fracture susceptibility and mild bronchiectasis. She had one healthy child age 32, after which she suffered a uterine prolapse. Examination revealed mild Marfanoid features. Uvula, skin and ophthalmological examination was normal. Results: Fibrillin-1 testing for Marfan syndrome (MFS) was negative. Detection of a c.1270G > C (p.Gly424Arg) TGFBR2 mutation confirmed the diagnosis of LDS. Losartan was started for vascular protection. Conclusions: LDS is a severe inherited vasculopathy that usually presents in childhood. It is characterized by aortic root dilatation and ascending aneurysms. There is a higher risk of aortic dissection compared with MFS. Clinical features overlap with MFS and Ehlers Danlos syndrome Type IV, but differentiating dysmorphogenic features include ocular hypertelorism, bifid uvula and cleft palate. Echocardiography and MRA or CT scanning from head to pelvis is recommended to establish the extent of vascular involvement. Management involves early surgical intervention, including early valve-sparing aortic root replacement, genetic counselling and close monitoring in pregnancy. Despite being caused by loss of function mutations in either TGFβ receptor, paradoxical activation of TGFβ signalling is seen, suggesting that TGFβ antagonism may confer disease modifying effects similar to those observed in MFS. TGFβ antagonism can be achieved with angiotensin antagonists, such as Losartan, which is able to delay aortic aneurysm development in preclinical models and in patients with MFS. Our case emphasizes the importance of timely recognition of vasculopathy syndromes in patients with hypermobility and the need for early surgical intervention. It also highlights their heterogeneity and the potential for late presentation. Disclosures: The authors have declared no conflicts of interes

CD4CD25 Regulatory Cells Contribute to the Regulation of Colonic Th2 Granulomatous Pathology Caused by Schistosome Infection

Eggs of the helminth Schistosoma mansoni accumulate in the colon following infection and generate Th2-biassed inflammatory granulomas which become down- modulated in size as the infection proceeds to chronicity. However, although CD4(+)CD25(+)FoxP3(+)regulatory T cells (T(regs)) are known to suppress Th1-mediated colitis, it is not clear whether they control Th2 -associated pathologies of the large intestine which characterise several helminth infections. Here we used a novel 3D-multiphoton confocal microscopy approach to visualise and quantify changes in the size and composition of colonic granulomas at the acute and chronic phases of S. mansoni infection. We observed decreased granuloma size, as well as reductions in the abundance of DsRed(+) T cells and collagen deposition at 14 weeks (chronic) compared to 8 weeks (acute) post-infection. Th2 cytokine production (i.e. IL-4, IL-5) in the colonic tissue and draining mesenteric lymph node (mLN) decreased during the chronic phase of infection, whilst levels of TGF-ß1 increased, co-incident with reduced mLN proliferative responses, granuloma size and fibrosis. The proportion of CD4(+)CD25(+)FoxP3(+)T(regs): CD4(+) cells in the mLN increased during chronic disease, while within colonic granulomas there was an approximate 4-fold increase. The proportion of CD4(+)CD25(+)FoxP3(+)T(regs) in the mLN that were CD103(+) and CCR5(+) also increased indicating an enhanced potential to home to intestinal sites. CD4(+)CD25(+) cells suppressed antigen-specific Th2 mLN cell proliferation in vitro, while their removal during chronic disease resulted in significantly larger granulomas, partial reversal of Th2 hypo-responsiveness and an increase in the number of eosinophils in colonic granulomas. Finally, transfer of schistosome infection-expanded CD4(+)CD25(+)T(regs) down-modulated the development of colonic granulomas, including collagen deposition. Therefore, CD4(+)CD25(+)FoxP3(+)T(regs) appear to control Th2 colonic granulomas during chronic infection, and are likely to play a role in containing pathology during intestinal schistosomiasis

Home-based versus centre-based cardiac rehabilitation

Background Cardiovascular disease is the most common cause of death globally. Traditionally, centre‐based cardiac rehabilitation programmes are offered to individuals after cardiac events to aid recovery and prevent further cardiac illness. Home‐based cardiac rehabilitation programmes have been introduced in an attempt to widen access and participation. This is an update of a review previously published in 2009 and 2015. Objectives: To compare the effect of home‐based and supervised centre‐based cardiac rehabilitation on mortality and morbidity, exercise‐capacity, health‐related quality of life, and modifiable cardiac risk factors in patients with heart disease. Search methods: We updated searches from the previous Cochrane Review by searching the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (Ovid), Embase (Ovid), PsycINFO (Ovid) and CINAHL (EBSCO) on 21 September 2016. We also searched two clinical trials registers as well as previous systematic reviews and reference lists of included studies. No language restrictions were applied. Selection criteria: We included randomised controlled trials, including parallel group, cross‐over or quasi‐randomised designs) that compared centre‐based cardiac rehabilitation (e.g. hospital, gymnasium, sports centre) with home‐based programmes in adults with myocardial infarction, angina, heart failure or who had undergone revascularisation. Data collection and analysis: Two review authors independently screened all identified references for inclusion based on pre‐defined inclusion criteria. Disagreements were resolved through discussion or by involving a third review author. Two authors independently extracted outcome data and study characteristics and assessed risk of bias. Quality of evidence was assessed using GRADE principles and a Summary of findings table was created. Main results: We included six new studies (624 participants) for this update, which now includes a total of 23 trials that randomised a total of 2890 participants undergoing cardiac rehabilitation. Participants had an acute myocardial infarction, revascularisation or heart failure. A number of studies provided insufficient detail to enable assessment of potential risk of bias, in particular, details of generation and concealment of random allocation sequencing and blinding of outcome assessment were poorly reported. No evidence of a difference was seen between home‐ and centre‐based cardiac rehabilitation in clinical primary outcomes up to 12 months of follow up: total mortality (relative risk (RR) = 1.19, 95% CI 0.65 to 2.16; participants = 1505; studies = 11/comparisons = 13; very low quality evidence), exercise capacity (standardised mean difference (SMD) = ‐0.13, 95% CI ‐0.28 to 0.02; participants = 2255; studies = 22/comparisons = 26; low quality evidence), or health‐related quality of life up to 24 months (not estimable). Trials were generally of short duration, with only three studies reporting outcomes beyond 12 months (exercise capacity: SMD 0.11, 95% CI ‐0.01 to 0.23; participants = 1074; studies = 3; moderate quality evidence). However, there was evidence of marginally higher levels of programme completion (RR 1.04, 95% CI 1.00 to 1.08; participants = 2615; studies = 22/comparisons = 26; low quality evidence) by home‐based participants. Authors' conclusions: This update supports previous conclusions that home‐ and centre‐based forms of cardiac rehabilitation seem to be similarly effective in improving clinical and health‐related quality of life outcomes in patients after myocardial infarction or revascularisation, or with heart failure. This finding supports the continued expansion of evidence‐based, home‐based cardiac rehabilitation programmes. The choice of participating in a more traditional and supervised centre‐based programme or a home‐based programme may reflect local availability and consider the preference of the individual patient. Further data are needed to determine whether the effects of home‐ and centre‐based cardiac rehabilitation reported in the included short‐term trials can be confirmed in the longer term and need to consider adequately powered non‐inferiority or equivalence study designs

Genotype and phenotype correlations in Iranian patients with hyperinsulinaemic hypoglycaemia.

Hyperinsulinaemic hypoglycaemia (HH) is a group of clinically and genetically heterogeneous disorders characterized by unregulated insulin secretion. Abnormalities in nine different genes (ABCC8, KCNJ11, GLUD1, GCK, HADH, SLC16A1, HNF4A, UCP2 and HNF1A) have been reported in HH, the most common being ABCC8 and KCNJ11. We describe the genetic aetiology and phenotype of Iranian patients with HH.This article is freely available via Open Access. Click on the 'Additional Link' above to access the full text