Objectives To investigate the possible role of Vitamin D (Vit D) deficiency via unregulated inflammation in COVID-19 complications and associated mortality. Design The time-adjusted case mortality ratio (T-CMR) was estimated as the number of deceased patients on day N divided by the number of confirmed cases on day N-8. The adaptive average of T-CMR (A-CMR) was further calculated as a metric of COVID-19 associated mortality in different countries. A model based on positivity change (PC) and an estimated prevalence of COVID-19 was developed to determine countries with similar screening strategies. Mean concentration of 25-hydroxyvitamin D (25(OH)D) in elderly individuals in countries with similar screening strategies were compared to investigate the potential impact of Vit D on A-CMR. We analyzed data showing a possible association between high C-Reactive Protein (CRP) concentration (CRP greater than or equal to 1 mg/dL) and severe COVID-19. We estimated a link between Vit D status and high CRP in healthy subjects (CRP greater than or equal to 0.2 mg/dL) with an adjustment for age and income to explore the possible role of Vit D in reducing complications attributed to unregulated inflammation and cytokine production. Data Sources Daily admission, recovery, and deceased rate data for patients with COVID-19 were collected from Kaggle as of April 20, 2020. Screening data were collected from Our World in Data and official statements from public authorities. The mean concentration of 25(OH)D among the elderly for comparison with A-CMR was collected from previously published studies from different countries. Chronic factor data used in regression analysis was obtained from published articles. The correlation between Vit D and CRP was calculated based on 9,212 subject-level data from NHANES, 2009-2010. Results A link between 25(OH)D and A-CMR in the US, France, Iran and the UK (countries with similar screening status) may exist. We observed an inverse correlation (correlation coefficient ranging from -0.84 to -1) between high CRP and 25(OH)D. Age and the family income status also correlated to high CRP and subjects with higher age and lower family income presented more incidences of high CRP. Our analysis determined a possible link between high CRP and Vit D deficiency and calculated an OR of 1.8 with 95%CI (1.2 to 2.6) among the elderly (age greater than or equal to 60 yo) in low-income families and an OR of 1.9 with 95%CI (1.4 to 2.7) among the elderly (age greater than or equal to 60 yo) in high-income families. COVID-19 patient-level data shows a notable OR of 3.4 with 95%CI (2.15 to 5.4) for high CRP in severe COVID-19 patients. Conclusion Given that CRP is a surrogate marker for cytokine storm and is associated with Vit D deficiency, based on retrospective data and indirect evidence we see a possible role of Vit D in reducing complications attributed to unregulated inflammation and cytokine storm. Further research is needed to account for other factors through direct measurement of Vit D levels in COVID-19 patients.

Objectives We present evidence for a possible role of Vitamin D (VitD) deficiency in unregulated cytokine production and inflammation leading to complications in COVID-19 patients. Design The time-adjusted case mortality ratio (T-CMR) was estimated as the ratio of deceased patients on day N to the confirmed cases on day N-8. The adaptive average of T-CMR (A-CMR) was calculated as a metric of COVID-19 associated mortality. A model based on positivity change (PC) and an estimated prevalence of COVID-19 was used to determine countries with similar screening strategies. A possible association of A-CMR with the mean concentration of 25-hydroxyvitamin D (25(OH)D) in elderly individuals in countries with similar screening strategy was investigated. We considered high C-reactive protein (CRP) in severe COVID-19 patients (CRP ≥ 1 mg/dL) as a surrogate of a cytokine storm. We considered high-sensitivity CRP (hs-CRP) in healthy subjects as hs-CRP ≥ 0.2 mg/dL. Results A link between 25(OH)D and A-CMR in countries with similar screening strategy is evidence for VitD’s possible role in reducing unregulated cytokine production and inflammation among patients with severe COVID-19. We observed an odds ratio (OR) of 1.8 with 95% confidence interval (95% CI) (1.2 to 2.6) and an OR of 1.9 with 95% CI (1.4 to 2.7) for hs-CRP in VitD deficient elderly from low-income families and high-income families, respectively. COVID-19 patient-level data show an OR of 3.4 with 95% CI (2.15 to 5.4) for high CRP in severe COVID-19 patients. Conclusion We conclude that future studies on VitD’s role in reducing cytokine storm and COVID-19 mortality are warranted.

Extending across multiple length scales, dynamic chromatin structure is linked to transcription through the regulation of genome organization. However, no individual technique can fully elucidate this structure and its relation to molecular function at all length and time scales at both a single-cell level and a population level. Here, we present a multitechnique nanoscale chromatin imaging and analysis (nano-ChIA) platform that consolidates electron tomography of the primary chromatin fiber, optical super-resolution imaging of transcription processes, and label-free nano-sensing of chromatin packing and its dynamics in live cells. Using nano-ChIA, we observed that chromatin is localized into spatially separable packing domains, with an average diameter of around 200 nanometers, sub-megabase genomic size, and an internal fractal structure. The chromatin packing behavior of these domains exhibits a complex bidirectional relationship with active gene transcription. Furthermore, we found that properties of PDs are correlated among progenitor and progeny cells across cell division.

Chromatin organization over multiple length scales plays a critical role in the regulation of transcription. Deciphering the interplay of these processes requires high-resolution, three-dimensional, quantitative imaging of chromatin structure in vitro. Herein, we introduce ChromSTEM, a method that utilizes high-angle annular dark-field imaging and tomography in scanning transmission electron microscopy combined with DNA-specific staining for electron microscopy. We utilized ChromSTEM for an in-depth quantification of 3D chromatin conformation with high spatial resolution and contrast, allowing for characterization of higher-order chromatin structure almost down to the level of the DNA base pair. Employing mass scaling analysis on ChromSTEM mass density tomograms, we observed that chromatin forms spatially well-defined higher-order domains, around 80 nm in radius. Within domains, chromatin exhibits a polymeric fractal-like behavior and a radially decreasing mass-density from the center to the periphery. Unlike other nanoimaging and analysis techniques, we demonstrate that our unique combination of this high-resolution imaging technique with polymer physics-based analysis enables us to (i) investigate the chromatin conformation within packing domains and (ii) quantify statistical descriptors of chromatin structure that are relevant to transcription. We observe that packing domains have heterogeneous morphological properties even within the same cell line, underlying the potential role of statistical chromatin packing in regulating gene expression within eukaryotic nuclei.

With the textbook view of chromatin folding based on the 30-nm fiber being challenged, it has been proposed that interphase DNA has an irregular 10-nm nucleosome polymer structure whose folding philosophy is unknown. Nevertheless, experimental advances suggest that this irregular packing is associated with many nontrivial physical properties that are puzzling from a polymer physics point of view. Here, we show that the reconciliation of these exotic properties necessitates modularizing three-dimensional genome into tree data structures on top of, and in striking contrast to, the linear topology of DNA double helix. These functional modules need to be connected and isolated by an open backbone that results in porous and heterogeneous packing in a quasi-self-similar manner, as revealed by our electron and optical imaging. Our multiscale theoretical and experimental results suggest the existence of higher-order universal folding principles for a disordered chromatin fiber to avoid entanglement and fulfill its biological functions.