Methotrexate toxicity complicating a case of rheumatoid arthritis associated Interstitial Lung Disease: Lessons to learn

Rheumatoid arthritis (RA) is one of the most common types of autoimmune arthritis. It can also involve other organs, including vascular structures, and lungs which are affected in 60% to 80% of cases. Other complications may present as airway infections and drug related pulmonary toxicity. We present the case of 75-year-old male patient of North African decent that was hospitalized initially for chronic dyspnea associated with other systemic manifestations, and in whom we confirmed the diagnosis of Rheumatoid arthritis associated interstitial lung disease. The patient was treated with methotrexate (MTX) and later on, he developed a fatal case of methotrexate related pulmonary toxicity.

Single nucleus RNA sequencing reveals glial cell type-specific responses to ischemic stroke

Reactive neuroglia critically shape the braińs response to ischemic stroke. However, their phenotypic heterogeneity impedes a holistic understanding of the cellular composition and microenvironment of the early ischemic lesion. Here we generated a single cell resolution transcriptomics dataset of the injured brain during the acute recovery from permanent middle cerebral artery occlusion. This approach unveiled infarction and subtype specific molecular signatures in oligodendrocyte lineage cells and astrocytes, which ranged among the most transcriptionally perturbed cell types in our dataset. Specifically, we characterized and compared infarction restricted proliferating oligodendrocyte precursor cells (OPCs), mature oligodendrocytes and heterogeneous reactive astrocyte populations. Our analyses unveiled unexpected commonalities in the transcriptional response of oligodendrocyte lineage cells and astrocytes to ischemic injury. Moreover, OPCs and reactive astrocytes were involved in a shared immuno-glial cross talk with stroke specific myeloid cells. In situ, osteopontin positive myeloid cells accumulated in close proximity to proliferating OPCs and reactive astrocytes, which expressed the osteopontin receptor CD44, within the perilesional zone specifically. In vitro, osteopontin increased the migratory capacity of OPCs. Collectively, our study highlights molecular cross talk events which might govern the cellular composition and microenvironment of infarcted brain tissue in the early stages of recovery.

Exploring the heterogeneous transcriptional response of the CNS to systemic LPS and Poly(I:C)

Peripheral contact to pathogen-associated molecular patterns (PAMPs) evokes a systemic innate immune response which is rapidly relayed to the central nervous system (CNS). The remarkable cellular heterogeneity of the CNS poses a significant challenge to the study of cell type and stimulus dependent responses of neural cells during acute inflammation. Here we utilized single nuclei RNA sequencing (snRNAseq), serum proteome profiling and primary cell culture methods to systematically compare the acute response of the mammalian brain to the bacterial PAMP lipopolysaccharide (LPS) and the viral PAMP polyinosinic:polycytidylic acid (Poly(I:C)), at single cell resolution. Our study unveiled convergent transcriptional cytokine and cellular stress responses in brain vascular and ependymal cells and a downregulation of several key mediators of directed blood brain barrier (BBB) transport. In contrast the neuronal response to PAMPs was limited in acute neuroinflammation. Moreover, our study highlighted the dominant role of IFN signalling upon Poly(I:C) challenge, particularly in cells of the oligodendrocyte lineage. Collectively our study unveils heterogeneous, shared and distinct cell type and stimulus dependent acute responses of the CNS to bacterial and viral PAMP challenges. Our findings highlight inflammation induced dysregulations of BBB-transporter gene expression, suggesting potential translational implications on drug pharmacokinetics variability during acute neuroinflammation. The pronounced dependency of oligodendrocytes on IFN stimulation during viral PAMP challenges, emphasizes their limited molecular viral response repertoire.

Parental consanguinity among parents of neonates with congenital hypothyroidism in Isfahan

We determined the prevalence of congenital hypothyroidism and the rate of consanguin-ity among parents of hypothyroid neonates among 93 381 neonates born in 17 hospitals in Isfahan from May 2002 to April 2005. Serum thyroxine (T4) and thyroid stimulating hormone (TSH) levels were measured on the 3rd-7th day of birth and neonates with abnormal levels were recalled and the levels reassessed. Those with TSH > or = 10 mlU/L and T4 < 6.5 microg/dL on the second assay were considered hypothyroid. In all, 1038 neonates were recalled and 274 were diagnosed as hypothyroid. There was a significant association between parental consanguinity and congenital hypothyroidism (P = 0.006); congenital hypothyroidism was commoner in neonates with 1st cousin parental consanguinity than 2nd cousin parental consanguinity (P = 0.008).