Renewal of embryonic and neonatal-derived cardiac-resident macrophages in response to environmental cues abrogated their potential to promote cardiomyocyte proliferation via Jagged-1-Notch1

Cardiac-resident macrophages (CRMs) play important roles in homeostasis, cardiac function, and remodeling. Although CRMs play critical roles in cardiac regeneration of neonatal mice, their roles are yet to be fully elucidated. Therefore, this study aimed to investigate the dynamic changes of CRMs during cardiac ontogeny and analyze the phenotypic and functional properties of CRMs in the promotion of cardiac regeneration. During mouse cardiac ontogeny, four CRM subsets exist successively: CX3CR1+CCR2-Ly6C-MHCII- (MP1), CX3CR1lowCCR2lowLy6C-MHCII- (MP2), CX3CR1-CCR2+Ly6C+MHCII- (MP3), and CX3CR1+CCR2-Ly6C-MHCII+ (MP4). MP1 cluster has different derivations (yolk sac, fetal liver, and bone marrow) and multiple functions population. Embryonic and neonatal-derived-MP1 directly promoted cardiomyocyte proliferation through Jagged-1-Notch1 axis and significantly ameliorated cardiac injury following myocardial infarction. MP2/3 subsets could survive throughout adulthood. MP4, the main population in adult mouse hearts, contributed to inflammation. During ontogeny, MP1 can convert into MP4 triggered by changes in the cellular redox state. These findings delineate the evolutionary dynamics of CRMs under physiological conditions and found direct evidence that embryonic and neonatal-derived CRMs regulate cardiomyocyte proliferation. Our findings also shed light on cardiac repair following injury.

First presentation of systemic lupus erythematosus as interstitial lung disease: a unique scenario

Interstitial lung disease [ILD] is regarded as an unusual manifestation of systemic lupus erythematosus [SLE]. ILD in SLE patients usually develop in long-standing disease course and follows a chronic course. Isolated presentation of ILD in SLE without another involvement is quite striking. We report such a unique case where patient's first presentation in SLE was ILD

Shedding light on a painful rash

We present a case of a rare inherited disorder - erythropoietic protoporphyria - with typical clinical manifestations. The diagnosis was suspected on the basis of a history of a light-sensitive rash and characteristic liver biopsy, and confirmed with genetic testing. The patient was followed up for more than 20 years, and ultimately developed the uncommon associated complication of liver cirrhosis. The clinical features, pathogenesis and management of erythropoietic protoporphyria are discussed herein