Hypovitaminosis D is associated with impaired neuromuscular function, bone loss, and fractures. If a person is not taking a vitamin supplement, sun exposure is often the greatest source of vitamin D. Thus, vitamin D deficiency is not uncommon in the winter, particularly in northern latitudes. Our goal was to establish the prevalence of vitamin D deficiency in south Florida (U.S.), a region of year-round sunny weather. At the end of the winter, 212 men and women attending an internal medicine clinic at a local county hospital were enrolled for measurements of 25-hydroxyvitamin D [25(OH)D], 1,25-dihydroxyvitamin D, and PTH; 99 participants returned at the end of summer. The mean (+/-sd) winter 25(OH)D concentration was 24.9 +/- 8.7 ng/ml (62.3 +/- 21.8 nmol/liter) in men and 22.4 +/- 8.2 ng/ml (56.0 +/- 20.5 nmol/liter) in women. In winter, the prevalence of hypovitaminosis D, defined as 25(OH)D less than 20 ng/ml (50 nmol/liter), was 38% and 40% in men and women, respectively. In the 99 subjects who returned for the end of summer visit, the mean 25(OH)D concentration was 31.0 +/- 11.0 ng/ml (77.5 +/- 27.5 nmol/liter) in men and 25.0 +/- 9.4 ng/ml (62.5 +/- 23.5 nmol/liter) in women. Seasonal variation represented a 14% summer increase in 25(OH)D concentrations in men and a 13% increase in women, both of which were statistically significant. The prevalence of hypovitaminosis D is considerable even in southern latitudes and should be taken into account in the evaluation of postmenopausal and male osteoporosis.

Schwann cell (SC) differentiation into a myelinating cell requires concurrent interactions with basal lamina and an axon destined for myelination. As SCs differentiate, they undergo progressive morphological changes and initiate myelin-specific gene expression. We find that disrupting actin polymerization with cytochalasin D (CD) inhibits myelination of SC/neuron co-cultures. Basal lamina is present, neurons are healthy, and the inhibition is reversible. Electron microscopic analysis reveals that actin plays a role at two stages of SC differentiation. At 0.75-1.0 microg/ml CD, SCs do not differentiate and appear as "rounded" cells in contact with axons. This morphology is consistent with disruption of actin filaments and cell shape changes. However, at 0.25 microg/ml CD, SCs partially differentiate; they elongate and segregate axons but generally fail to form one-to-one relationships and spiral around the axon. In situ hybridizations reveal that SCs in CD-treated cultures do not express mRNAs encoding the myelin-specific proteins 2',3'-cyclic nucleotide phosphodiesterase (CNP), myelin-associated glycoprotein (MAG), and P0. Our results suggest that at the lower CD dose, SCs commence differentiation as evidenced by changes in cell shape but are unable to elaborate myelin lamellae because of a lack of myelin-specific mRNAs. We propose that F-actin influences myelin-specific gene expression in SCs.

Highlights d IL-1b-driven increased intestinal permeability is observed in murine KD model d Blocking intestinal permeability or IgA production decreases murine KD vasculitis d IgA and IgA-C3 are observed in cardiovascular lesions of murine KD model d KD vasculitis may be a form of IgA vasculitis involving a gutvascular axis

Rationale: NLRP3 activation and IL-1β production are implicated in Kawasaki Disease (KD) pathogenesis, however a detailed and complete characterization of the molecular networks and cellular subsets involved in the development of cardiovascular lesions is still lacking. Objective: Here, in a murine model of KD vasculitis, we used single-cell RNA sequencing and spatial transcriptomics to determine the cellular landscape of inflamed vascular tissues. Methods and Results: We observe infiltrations of innate and adaptive immune cells in murine KD cardiovascular lesions, associated with increased expression of Nlrp3 and Il1b. Monocytes, macrophages and dendritic cells were the main sources of IL-1β, whereas fibroblasts and vascular smooth muscle cells (VSMCs) expressed high levels of IL-1 receptor. VSMCs type 1 surrounding the inflamed coronary artery undergo a phenotype switch to become VSMCs type 2, which are characterized by gene expression changes associated with decreased contraction, and enhanced migration and proliferation. Genetic inhibition of IL-1β signaling on VSMCs efficiently attenuated the VSMCs type 2 phenotypic switch and the development of cardiovascular lesions during murine KD vasculitis. In addition, pharmacological inhibition of NLRP3 prevented the development of cardiovascular inflammation. Conclusions: Our studies unravel the cellular diversity involved in IL-1β production and signaling in murine KD cardiovascular lesions and provide the rationale for therapeutic strategies targeting NLRP3 to inhibit cardiovascular lesions associated with KD.

Immature spinal cord, unlike adult, has an ability to repair itself following injury. Evidence for regeneration, structural repair and development of substantially normal locomotor behaviour comes from studies of marsupials due to their immaturity at birth. We have compared morphological, cellular and molecular changes in spinal cords transected at postnatal day (P)7 or P14, from 3 h to 2 weeks post-injury, in South American opossums (Monodelphis domestica). A bridge between severed ends of cords was apparent 5 days post-injury in P7 cords, compared to 2 weeks in P14. The volume of neurofilament (axonal) material in the bridge 2 weeks after injury was 30% of control in P7- but < 10% in P14-injured cords. Granulocytes accumulated at the site of injury earlier (3 h) in P7 than in P14 (24 h)-injured animals. Monocytes accumulated 24 h post-injury and accumulation was greater in P14 cords. Accumulation of GFAP-positive astrocytes at the lesion occurred earlier in P14-injured cords. Neurites and growth cones were identified ultrastructurally in contact with astrocytes forming the bridge. Results using mouse inflammatory gene arrays showed differences in levels of expression of many TGF, TNF, cytokine, chemokine and interleukin gene families. Most of the genes identified were up-regulated to a greater extent following injury at P7. Some changes were validated and quantified by RT-PCR. Overall, the results suggest that at least some of the greater ability to recover from spinal cord transection at P7 compared to P14 in opossums is due to differences in inflammatory cellular and molecular responses.