Diabetic retinopathy in Down's syndrome

Moyamoya Disease Associated with Graves' Disease and Down Syndrome: A Case Report and Literature Review

BACKGROUND

Moyamoya vessels are cerebral vasculopathies characterized by net-like collateral vessel formation at the cerebral basal area and stenosis of the terminal internal carotid artery, proximal middle cerebral artery, and anterior cerebral artery. A diagnosis of Moyamoya disease depends on the bilateral presence of Moyamoya vessels. Moyamoya disease associated with Graves' disease has rarely been reported to be a cause of ischemic events due to hyperthyroidism. However, there are extremely rare cases of Moyamoya disease with concurrent Graves' disease and Down syndrome. We aimed to report such a case, and to compare these cases' clinical features, pathogenesis, and treatment effects to those of the cases of concurrent Moyamoya disease and Graves' disease alone.

METHODS

We performed an English literature search using the PubMed database and the keywords Moyamoya, quasi-Moyamoya, Graves' disease, thyrotoxicosis, Down syndrome, and trisomy 21.

RESULTS

Only five cases of Moyamoya disease with Graves' disease and Down syndrome have been reported, including our own. Four patients were female (80%), and all underwent antithyroid therapy and experienced ischemic episodes, including transient ischemic attacks. At the time of their vascular accident, two patients were in a thyrotoxic state; only our patient was in a euthyroid state. The mean age was 15.6 years (standard deviation: 6.1), which was younger than the mean age of 31.4 years (standard deviation: 13) in patients with Moyamoya disease and Graves' disease alone. Down syndrome is commonly associated with abnormal vascular networks due to increased endostatin concentrations or immunological abnormalities such as those that occur in Graves' disease. Graves' disease accelerates the progression of Moyamoya disease and ischemic attacks due to atherosclerosis, enhances sympathetic nervous system activity and immunological changes. As compared to Moyamoya disease patients, patients with concurrent Graves' disease only and Moyamoya disease patients with concurrent Graves' disease and Down syndrome may experience accelerated disease progression or more frequent ischemic attacks.

CONCLUSION

Early imaging follow-ups and strict control of thyroid function are necessary in such cases; if ischemic attacks have already occurred, revascularization surgery may be effective.

Co-occurring medical conditions in adults with Down syndrome: A systematic review toward the development of health care guidelines. Part II

Adults with Down syndrome (DS) represent a unique population who are in need of clinical guidelines to address their medical care. Many of these conditions are of public health importance with the potential to develop screening recommendations to improve clinical care for this population. Our workgroup previously identified and prioritized co-occurring medical conditions in adults with DS. In this study, we again performed detailed literature searches on an additional six medical conditions of clinical importance. A series of key questions (KQ) were formulated a priori to guide the literature search strategy. Our KQs focused on disease prevalence, severity, risk-factors, methodologies for screening/evaluation, impact on morbidity, and potential costs/benefits. The available evidence was extracted, evaluated and graded on quality. The number of participants and the design of clinical studies varied by condition and were often inadequate for answering most of the KQ. Based upon our review, we provide a summary of the findings on hip dysplasia, menopause, acquired cardiac valve disease, type 2 diabetes mellitus, hematologic disorders, and dysphagia. Minimal evidence demonstrates significant gaps in our clinical knowledge that compromises clinical decision-making and management of these medically complex individuals. The creation of evidence-based clinical guidance for this population will not be possible until these gaps are addressed.

Illustration of tessellation in Down syndrome

Background: Tessellated fundus refers to a specific change in the appearance of the internal layers of the eye in which the choroidal large vessels became visible through polygonal hypopigmented areas. Such hypopigmented areas alternate with hyperpigmented zones in a tigroid pattern. Fundus tessellation is often associated with myopia and choroidal thinning.Materials and Methods: We analyzed fundus images from 50 children with Down syndrome and 52 controls.Results: Tessellation was present in 64% of children with Down syndrome, compared with only 13.5% of controls (p < .0001). In most cases, tessellation was located peripapillary, and no difference was observed in tessellation localization between children with Down syndrome and controls (p = .60). Although more prevalent in myopic children with and without Down syndrome, tessellation was present in almost half (48%) of children with Down syndrome with hyperopia versus only 5% of controls with the same refractive status.Conclusions: Mechanical stretching of the choroid could explain the high rate of tessellation in myopes. Other factors must contribute to the higher prevalence of tessellated fundus in children with Down syndrome without myopia. We discuss potentially relevant factors and propose vascular involvement as a contributor to tessellation in our population with Down syndrome. Further studies assessing choroidal vasculature in individuals with Down syndrome are needed to confirm this theory.

Understanding the Multifaceted Role of Human Down Syndrome Kinase DYRK1A

The dual-specificity tyrosine (Y) phosphorylation-regulated kinase DYRK1A, also known as Down syndrome (DS) kinase, is a dosage-dependent signaling kinase that was originally shown to be highly expressed in DS patients as a consequence of trisomy 21. Although this was evident some time ago, it is only in recent investigations that the molecular roles of DYRK1A in a wide range of cellular processes are becoming increasingly apparent. Since initial knowledge on DYRK1A became evident through minibrain mnb, the Drosophila homolog of DYRK1A, this review will first summarize the scientific reports on minibrain and further expand on the well-established neuronal functions of mammalian and human DYRK1A. Recent investigations across the current decade have provided rather interesting and compelling evidence in establishing nonneuronal functions for DYRK1A, including its role in infection, immunity, cardiomyocyte biology, cancer, and cell cycle control. The latter part of this review will therefore focus in detail on the emerging nonneuronal functions of DYRK1A and summarize the regulatory role of DYRK1A in controlling Tau and α-synuclein. Finally, the emerging role of DYRK1A in Parkinson's disease will be outlined.

Trisomy 21 and Risk of Retinopathy of Prematurity

BACKGROUND AND OBJECTIVES

Trisomy 21 is known to decrease the risk of several (nonocular) angiogenic-mediated diseases. The objective of this study was to determine whether trisomy 21 can also be shown to be significantly protective against ocular angiogenic-mediated disorders such as retinopathy of prematurity (ROP).

METHODS

A retrospective analysis of deidentified data from the Pediatrix BabySteps Clinical Warehouse. This large repository of neonatal data is approved for use in research studies by the Western Institutional Review Board. The study population consisted of 99,080 infants with very low birth weights (BWs; BW <1500 g), born between 1996 and 2013, cared for at >300 US NICUs, and who had been discharged alive from hospital. Statistical significance for unadjusted comparisons between groups was determined with Pearson's χ(2) test or Student's t test. Logistic regression models were used to calculate the odds of ROP (of any stage) and advanced ROP (stage 3 or greater) for infants with trisomy 21 compared with all other infants.

RESULTS

The prevalence of trisomy 21 was 0.3% in the study population (321 of 99,080). After adjustment for BW, gestational age, oxygen exposure, and other potential confounders, there was an odds ratio of 0.6 (95% confidence interval: 0.5-0.8) for ROP in infants with trisomy 21compared with other infants and an odds ratio of 0.4 (95% confidence interval: 0.1-0.9) for advanced-stage ROP.

CONCLUSIONS

Trisomy 21 significantly decreases the odds for ROP in very low BW infant survivors. This study unmasks a potentially identifiable genetic component to ROP risk, paving the way for the development of a laboratory-based ROP screening tool.

Moyamoya Syndrome: A Window of Moyamoya Disease

Moyamoya-like vasculopathy develops in association with various systemic diseases and conditions, which is termed moyamoya syndrome. Relatively common diseases and conditions are related to moyamoya syndrome, including neurofibromatosis type 1, Down syndrome, thyroid disease, and cranial irradiation. Moyamoya syndrome shares phenotypical characteristics with idiopathic moyamoya disease. However, they differ in other details, including clinical presentations, natural history, and treatment considerations. The study of moyamoya syndrome can provide clinicians and researchers with valuable knowledge and insight. Although it is infrequently encountered in clinical practice, moyamoya-like vasculopathy can severely complicate outcomes for patients with various underlying diseases when the clinician fails to expect or diagnose moyamoya syndrome development. Furthermore, moyamoya syndrome could be used as a doorway to more enigmatic moyamoya disease in research. More comprehensive survey and investigation are required to uncover the secrets of all the moyamoya-like phenomena.

A single extra copy of Dscr1 improves survival of mice developing spontaneous lung tumors through suppression of tumor angiogenesis

The incidence of most solid tumors is remarkably reduced in individuals with Down syndrome. Using mouse models of Down syndrome, we have previously shown that this decrease in tumor incidence is due, in part, to suppression of tumor angiogenesis as a consequence of attenuated calcineurin signaling in endothelial cells. Our prior studies utilized xenografted tumors in a transgenic mouse model with three copies of the Down syndrome critical region-1 (Dscr1) gene, a chromosome 21-encoded endogenous calcineurin inhibitor. These data indicate that upregulated Dscr1 contributes to broad cancer protection by suppressing tumor angiogenesis through inhibiting the calcineurin pathway in the vascular endothelium. However, it still remains to be confirmed whether a single extra copy of Dscr1 is also sufficient to suppress tumor angiogenesis in slow growing spontaneous tumors that more accurately recapitulate molecular features of human malignancies. In this study, utilizing LSL-Kras(G12D) mice, an inducible and autochthonous model of human lung adenocarcinoma, on a Dscr1 transgenic mouse background, we show that a single extra transgenic copy of Dscr1 provides a survival advantage in these mice developing spontaneous lung tumors driven by oncogenic Kras(G12D) without affecting either initiation or progression of spontaneous lung tumors. Furthermore, we show that Dscr1 trisomy significantly reduces microvessel density in lung tumors and thus limits the growth of lung tumors through decreased proliferation and increased apoptosis of lung tumor cells. These data provide evidence that a single extra copy of Dscr1 is sufficient to suppress tumor angiogenesis during spontaneous lung tumorigenesis and further support our hypothesis that suppression of tumor angiogenesis by an additional copy of Dscr1 contributes to the reduced cancer incidence in individuals with Down syndrome and the calcineurin pathway in the tumor vasculature is a potential target for cancer treatment.

[Trisomy 21 and cancers]

Patients with trisomy 21, still called Down's syndrome (DS), present a particular tumoral profile compared to the general population with an increased incidence of leukaemia in the childhood and a low risk of solid cancer in the adulthood. DS children indeed present a 50-fold risk of developing a leukaemia compared to age-matched non-trisomic children and most of them develop a specific myelodysplasic disorder called transient myelodysplasic disorder. In spite of the low incidence of solid tumors, some are very rare as breast cancer, nephroblastoma, neuroblastoma and medulloblastoma, whereas the others remain more frequent as retinoblastoma, lymphoma and gonadal and extragonadal germ cell tumours. In this review, we present possible mechanisms which can favour, or on the contrary repress the formation and progression of tumours in DS patients, which are related to gene effect dosage of oncogenes or tumour repressors on chromosome 21, tumour angiogenesis, apoptosis and epithelial cell-stroma interactions.

Identification of novel candidate maternal serum protein markers for Down syndrome by integrated proteomic and bioinformatic analysis

OBJECTIVE

This study aimed to identify candidate protein biomarkers from maternal serum for Down syndrome (DS) by integrated proteomic and bioinformatics analysis.

METHODS

A pregnancy DS group of 18 women and a control group with the same number were prepared, and the maternal serum proteins were analyzed by isobaric tags for relative and absolute quantitation and mass spectrometry, to identify DS differentially expressed maternal serum proteins (DS-DEMSPs). Comprehensive bioinformatics analysis was then employed to analyze DS-DEMSPs both in this paper and seven related publications.

RESULTS

Down syndrome differentially expressed maternal serum proteins from different studies are significantly enriched with common Gene Ontology functions, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways, transcription factor binding sites, and Pfam protein domains, However, the DS-DEMSPs are less functionally related to known DS-related genes. These evidences suggest that common molecular mechanisms induced by secondary effects may be present upon DS carrying. A simple scoring scheme revealed Alpha-2-macroglobulin, Apolipoprotein A1, Apolipoprotein E, Complement C1s subcomponent, Complement component 5, Complement component 8, alpha polypeptide, Complement component 8, beta polypeptide and Fibronectin as potential DS biomarkers.

CONCLUSION

The integration of proteomics and bioinformatics studies provides a novel approach to develop new prenatal screening methods for noninvasive yet accurate diagnosis of DS.

VEGF and nitric oxide synthase immunoexpression in Down's syndrome amniotic fluid stem cells

BACKGROUND

It has been previously observed that the amniotic fluid obtained from Down's syndrome (DS) pregnancies showed lower levels of vascular endothelial growth factor (VEGF) and higher levels of nitric oxide (NO) with respect to the controls, suggesting the presence of an imbalance between placental vascularization and altered endothelial function. The aim of our study was to evaluate the immunohistochemical expression and localization of VEGF and nitric oxide synthase (NOS) isoforms in cultured amniotic fluid mesenchymal stem cells (AF-MSCs) isolated from normal euploid pregnancies and pregnancies complicated by trisomy 21. In addition, we measured the VEGF and NO content in cell culture supernatants to analyse their production by AF-MSCs.

MATERIALS AND METHODS

AF-MSCs were obtained from women with foetal DS and controls matched for age and gestation, and expanded in culture. The cells were then evaluated for the immunohistochemical expression of VEGF and NOS isoforms, as well as for the release of VEGF and NO.

RESULTS

Our analyses showed that both the VEGF expression and production were significantly lower in DS-AF-MSCs with respect to the controls. As regards NOS, immunohistochemical expression of eNOS was significantly reduced in DS-AF-MSCs, whereas the nNOS and iNOS were similarly immunoexpressed in both groups of cells. Moreover, we observed that the NO content was significantly higher in medium derived by DS-AF-MSCs.

CONCLUSIONS

Our study shows, for the first time, the differences between AF-MSCs isolated from control and trisomy 21 pregnancies and suggest an involvement of NO and VEGF in the physiopathological mechanisms associated with DS pregnancy.

Survival and morbidity outcomes for very low birth weight infants with Down syndrome

OBJECTIVE

Our objective was to compare survival and neonatal morbidity rates between very low birth weight (VLBW) infants with Down syndrome (DS) and VLBW infants with non-DS chromosomal anomalies, nonchromosomal birth defects (BDs), and no chromosomal anomaly or major BD.

METHODS

Data were collected prospectively for infants weighing 401 to 1500 g who were born and/or cared for at one of the study centers participating in the Eunice Kennedy Shriver National Institute of Child Health and Human Development Neonatal Research Network in 1994-2008. Risk of death and morbidities, including patent ductus arteriosus (PDA), necrotizing enterocolitis (NEC), late-onset sepsis (LOS), retinopathy of prematurity, and bronchopulmonary dysplasia (BPD), were compared between VLBW infants with DS and infants in the other groups.

RESULTS

Infants with DS were at increased risk of death (adjusted relative risk: 2.47 [95% confidence interval: 2.00-3.07]), PDA, NEC, LOS, and BPD, relative to infants with no BDs. Decreased risk of death (relative risk: 0.40 [95% confidence interval: 0.31-0.52]) and increased risks of NEC and LOS were observed when infants with DS were compared with infants with other non-DS chromosomal anomalies. Relative to infants with nonchromosomal BDs, infants with DS were at increased risk of PDA and NEC.

CONCLUSION

The increased risk of morbidities among VLBW infants with DS provides useful information for counseling parents and for anticipating the need for enhanced surveillance for prevention of these morbidities.

Impairment of circulating endothelial progenitors in Down syndrome

BACKGROUND

Pathological angiogenesis represents a critical issue in the progression of many diseases. Down syndrome is postulated to be a systemic anti-angiogenesis disease model, possibly due to increased expression of anti-angiogenic regulators on chromosome 21. The aim of our study was to elucidate some features of circulating endothelial progenitor cells in the context of this syndrome.

METHODS

Circulating endothelial progenitors of Down syndrome affected individuals were isolated, in vitro cultured and analyzed by confocal and transmission electron microscopy. ELISA was performed to measure SDF-1α plasma levels in Down syndrome and euploid individuals. Moreover, qRT-PCR was used to quantify expression levels of CXCL12 gene and of its receptor in progenitor cells. The functional impairment of Down progenitors was evaluated through their susceptibility to hydroperoxide-induced oxidative stress with BODIPY assay and the major vulnerability to the infection with human pathogens. The differential expression of crucial genes in Down progenitor cells was evaluated by microarray analysis.

RESULTS

We detected a marked decrease of progenitors' number in young Down individuals compared to euploid, cell size increase and some major detrimental morphological changes. Moreover, Down syndrome patients also exhibited decreased SDF-1α plasma levels and their progenitors had a reduced expression of SDF-1α encoding gene and of its membrane receptor. We further demonstrated that their progenitor cells are more susceptible to hydroperoxide-induced oxidative stress and infection with Bartonella henselae. Further, we observed that most of the differentially expressed genes belong to angiogenesis, immune response and inflammation pathways, and that infected progenitors with trisomy 21 have a more pronounced perturbation of immune response genes than infected euploid cells.

CONCLUSIONS

Our data provide evidences for a reduced number and altered morphology of endothelial progenitor cells in Down syndrome, also showing the higher susceptibility to oxidative stress and to pathogen infection compared to euploid cells, thereby confirming the angiogenesis and immune response deficit observed in Down syndrome individuals.

Down's syndrome in diabetic patients aged <20 years: an analysis of metabolic status, glycaemic control and autoimmunity in comparison with type 1 diabetes

AIMS/HYPOTHESIS

Intellectual impairment in individuals with Down's syndrome and diabetes mellitus potentially limits the quality of diabetic control. In addition, these patients are at risk of having immunological abnormalities. The present study compared metabolic status and concomitant diseases in young (<20 years old) Down's syndrome patients with diabetes vs young type 1 diabetic patients.

METHODS

The Diabetes-Patienten-Verlaufsdaten is a longitudinal follow-up database, which collects data from 298 German and Austrian diabetes centres. Data available on diabetic patients aged <20 years were analysed statistically.

RESULTS

We compared data for 159 Down's syndrome patients with diabetes and 41,983 type 1 diabetic patients. The former used less insulin, but showed better glycaemic control (HbA1c). Diabetes onset during the first 3 years of life occurred in 18.9% of Down's syndrome patients with diabetes and in 6.4% of type 1 diabetic patients. Antibody titres indicative of coeliac disease and thyroid peroxidase antibodies were more frequent in Down's syndrome patients with diabetes. No significant differences were found regarding the beta cell autoantibodies studied.

CONCLUSIONS/INTERPRETATION

The age-of-onset distribution showed a shift towards younger ages and was bimodal in the Down's syndrome group. The better metabolic control found, despite intellectual impairment, in young Down's syndrome patients with diabetes cannot be conclusively explained by our data, but is likely to be due to a less complex lifestyle. Our data provide further confirmation that coeliac and thyroid antibodies are more prevalent in Down's syndrome. The presence of beta cell autoantibodies supports an autoimmune cause of diabetes in some children with Down's syndrome.

Tumor angiogenesis: insights and innovations

Angiogenesis is a vital process resulting in the formation of new blood vessels. It is normally a highly regulated process that occurs during human development, reproduction, and wound repair. However, angiogenesis can also become a fundamental pathogenic process found in cancer and several other diseases. To date, the inhibition of angiogenesis has been researched at both the bench and the bedside. While several studies have found moderate improvements when treating with angiogenesis inhibitors, greater success is being seen when the inhibition of angiogenesis is combined with other traditional forms of available therapy. This review summarizes several important angiogenic factors, examines new research and ongoing clinical trials for such factors, and attempts to explain how this new knowledge may be applied in the fight against cancer and other angiogenic-related diseases.

Down's syndrome suppression of tumour growth and the role of the calcineurin inhibitor DSCR1

The incidence of many cancer types is significantly reduced in individuals with Down's syndrome, and it is thought that this broad cancer protection is conferred by the increased expression of one or more of the 231 supernumerary genes on the extra copy of chromosome 21. One such gene is Down's syndrome candidate region-1 (DSCR1, also known as RCAN1), which encodes a protein that suppresses vascular endothelial growth factor (VEGF)-mediated angiogenic signalling by the calcineurin pathway. Here we show that DSCR1 is increased in Down's syndrome tissues and in a mouse model of Down's syndrome. Furthermore, we show that the modest increase in expression afforded by a single extra transgenic copy of Dscr1 is sufficient to confer significant suppression of tumour growth in mice, and that such resistance is a consequence of a deficit in tumour angiogenesis arising from suppression of the calcineurin pathway. We also provide evidence that attenuation of calcineurin activity by DSCR1, together with another chromosome 21 gene Dyrk1a, may be sufficient to markedly diminish angiogenesis. These data provide a mechanism for the reduced cancer incidence in Down's syndrome and identify the calcineurin signalling pathway, and its regulators DSCR1 and DYRK1A, as potential therapeutic targets in cancers arising in all individuals.

Angiogenesis

Angiogenesis inhibitors for the treatment of cancer have now been approved by the Food and Drug Administration in the United States, and in 28 other countries including China. Clinical application of this new class of drugs is informed by certain principles from angiogenesis research. Oncogenic mutations initiate tumorigenesis, but angiogenesis is necessary for expansion of tumor mass. Two angiogenesis inhibitors have been developed that have a broad spectrum of anticancer activity, yet virtually no side effects. Endogenous angiogenesis inhibitors act as tumor suppressor proteins. The angiogenic response in vivo is based on the genetic background of the host. Several types of angiogenesis inhibitors reveal a biphasic, U-shaped curve of efficacy. "Antiangiogenic chemotherapy" is a novel approach to the treatment of drug resistance.

Endogenous angiogenesis inhibitors

When the FDA commissioner announced in February 2004 the approval of Avastin for the treatment of patients with colon cancer, he called angiogenesis inhibitors a fourth modality of anti-cancer therapy. Because angiogenesis inhibitors are relatively less toxic than conventional chemotherapy and have a lower risk of drug resistance, they may also represent a new class of anti-cancer agents, some of which have sufficiently reduced toxicity that they may be safely used long term. These include immunotherapy, vaccines, telomerase inhibitors, apoptosis inducers, low dose metronomic chemotherapy, novel hormonal therapies, gene therapy and others. However, at least 16 endogenous angiogenesis inhibitors have been discovered in the circulation, and/or in the extracellular matrix. These may become the safest and least toxic of anti-cancer therapies. Four are already being administered by injection in clinical trials for cancer. Recently, it has been reported that at least two endogenous angiogenesis inhibitors can be significantly increased in humans (endostatin), and in mice (thrombospondin), by oral administration of small molecules which themselves are already FDA approved for other uses. This finding suggests several new clinical applications for the future, including the possibility of guiding the use of angiogenesis inhibitors by blood or urinary biomarkers, currently being developed, that may detect the presence of cancer before it is symptomatic, or before it can be located by conventional methods.