Serum thrombopoietin level and thrombocytopenia during the neonatal period in infants with Down's syndrome

Proteomic profiles for Alzheimer's disease and mild cognitive impairment among adults with Down syndrome spanning serum and plasma: An Alzheimer's Biomarker Consortium-Down Syndrome (ABC-DS) study

INTRODUCTION

Previously generated serum and plasma proteomic profiles were examined among adults with Down syndrome (DS) to determine whether these profiles could discriminate those with mild cognitive impairment (MCI-DS) and Alzheimer's disease (DS-AD) from those cognitively stable (CS).

METHODS

Data were analyzed on n = 305 (n = 225 CS; n = 44 MCI-DS; n = 36 DS-AD) enrolled in the Alzheimer's Biomarker Consortium-Down Syndrome (ABC-DS).

RESULTS

Distinguishing MCI-DS from CS, the serum profile produced an area under the curve (AUC) = 0.95 (sensitivity [SN] = 0.91; specificity [SP] = 0.99) and an AUC = 0.98 (SN = 0.96; SP = 0.97) for plasma when using an optimized cut-off score. Distinguishing DS-AD from CS, the serum profile produced an AUC = 0.93 (SN = 0.81; SP = 0.99) and an AUC = 0.95 (SN = 0.86; SP = 1.0) for plasma when using an optimized cut-off score. AUC remained unchanged to slightly improved when age and sex were included. Eotaxin3, interleukin (IL)-10, C-reactive protein, IL-18, serum amyloid A , and FABP3 correlated fractions at r2 > = 0.90.

DISCUSSION

Proteomic profiles showed excellent detection accuracy for MCI-DS and DS-AD.

Incidence and consequences of neonatal alloimmune thrombocytopenia: a systematic review

BACKGROUND

Neonatal alloimmune thrombocytopenia (NAIT) is a potentially devastating disease that may lead to intracranial hemorrhage in the fetus or neonate, often with death or major neurologic damage. There are no routine screening programs for NAIT, preventive measures are taken only in a subsequent pregnancy. To estimate the population incidence of NAIT and its consequences, we conducted a review of the literature. Our results may aid in the design of a screening program.

METHODS

An electronic literature search included Medline, Embase, Cochrane database and references of retrieved articles. Eligible for inclusion were all prospective studies aimed at diagnosing NAIT in a general, nonselected newborn population, with sufficient information on platelet count at birth, bleeding complications, and treatment. Titles and abstracts were reviewed, followed by review of full text publications. Studies were independently assessed by 2 reviewers for methodologic quality. Disagreements were resolved by consensus, including a third reviewer.

RESULTS

From the initial 768 studies, 21 remained for full text analysis, 6 of which met the inclusion criteria. In total, 59,425 newborns were screened, with severe thrombocytopenia in 89 cases (0.15%). NAIT was diagnosed in 24 of these 89 newborns (27%). In 6 (25%) of these cases, an intracranial hemorrhage was found, all likely of antenatal origin.

CONCLUSIONS

NAIT is among the most important causes of neonatal thrombocytopenia. Intracranial hemorrhage due to NAIT occurs in 10 per 100 000 neonates, commonly before birth. Screening for NAIT might be effective but should be done antenatally.

Alterations of ectonucleotidases and acetylcholinesterase activities in lymphocytes of Down syndrome subjects: relation with inflammatory parameters

BACKGROUND

Subjects with Down syndrome (DS) have an increased susceptibility to infections and autoimmune disorders. ATP, adenosine, and acetylcholine contribute to the immune response regulation, and NTPDase, adenosine deaminase (ADA) and acetylcholinesterase (AChE) are important enzymes in the control of the extracellular levels of these molecules. We evaluated the activities of these enzymes and the cytokine levels in samples of DS individuals.

METHODS

The population consisted of 23 subjects with DS and 23 healthy subjects. Twelve milliliters of blood was obtained from each subject and used for lymphocyte and serum preparation. Lymphocytes were separated on Ficoll density gradients. After isolation, NTPDase and AChE activities were determined.

RESULTS

The NTPDase activity using ADP as substrate was increased in lymphocytes of DS patients compared to control (P<0.05); however, no alterations were observed in the ATP hydrolysis. An increase was observed in the AChE activity in lymphocytes and in ADA activity in serum of DS patients when compared to healthy subjects (P<0.05). In DS subjects, an increase in the levels of IL-1β, IL-6, TNF-α and IFN-γ and a decrease in the IL-10 levels were also observed (P<0.05).

CONCLUSIONS

Alterations in the NTPDase, ADA and AChE activities as well changes in the cytokine levels may contribute to immunological alterations observed in DS.

The calcineurin-NFAT pathway negatively regulates megakaryopoiesis

The calcium regulated calcineurin-nuclear factor of activated T cells (NFAT) pathway modulates the physiology of numerous cell types, including hematopoietic. Upon activation, calcineurin dephosphorylates NFAT family transcription factors, triggering their nuclear entry and activation or repression of target genes. NFATc1 and c2 isoforms are expressed in megakaryocytes. Moreover, human chromosome 21 (Hsa21) encodes several negative regulators of calcineurin-NFAT, candidates in the pathogenesis of Down syndrome (trisomy 21)-associated transient myeloproliferative disorder and acute megakaryoblastic leukemia. To investigate the role of calcineurin-NFAT in megakaryopoiesis, we examined wild-type mice treated with the calcineurin inhibitor cyclosporin A and transgenic mice expressing a targeted single extra copy of Dscr1, an Hsa21-encoded calcineurin inhibitor. Both murine models exhibited thrombocytosis with increased megakaryocytes and megakaryocyte progenitors. Pharmacological or genetic inhibition of calcineurin in mice caused accumulation of megakaryocytes exhibiting enhanced 5-bromo-2'-deoxyuridine uptake and increased expression of messenger RNAs encoding CDK4 and G1 cyclins, which promote cell division. Additionally, human megakaryocytes with trisomy 21 show increased proliferation and decreased NFAT activation compared with euploid controls. Our data indicate that inhibition of calcineurin-NFAT drives proliferation of megakaryocyte precursors by de-repressing genes that drive cell division, providing insights into mechanisms of normal megakaryopoiesis and megakaryocytic abnormalities that accompany Down syndrome.