Outcome of Infants Born to Women with Chronic Hepatitis B: A Local Risk-Based Strategy in a Low Prevalence Country

BACKGROUND

Chronic hepatitis-B virus (HBV) infection due to mother-to-child transmission (MTCT) during the perinatal period is an important global health concern. Chile is a low-prevalence country with an increasing migratory inflow from Latin- American countries, with intermediate to high endemic rates of HBV infection, and until 2021, there is no universal maternal screening. This study aimed to evaluate infant outcomes using a risk-based strategy of maternal screening to prevent MTCT of hepatitis B virus (HBV) in a low-prevalence country.

METHODS

This prospective study included infants born to HBsAg-positive women detected using a local risk-based strategy. The exposed infants received immunoprophylaxis (IP) and follow-up to evaluate their clinical outcomes and immune responses through post-serological vaccine testing (PSVT) after completing the three- dose schedule of the HBV vaccine.

RESULTS

A total of 99 HBsAg-positive mothers were detected. Seventy-six (82%) infants completed the follow-up and had PSVT between 9 and 12 months of age. 55.2% female, the median gestational age was 39 weeks (25-41) and the median birth weight was 3,130g (816-4,400 g). All patients received IP with recombinant HBV vaccine plus hepatitis-B virus immunoglobulin (HBIG) and three doses of the HBV vaccine. There were no cases of HBV infection, and 96% (72) responded to immunization with HBsAg antibodies (anti-HBsAg) >10 UI/ml, with a median level of 799 IU/ml.

CONCLUSIONS

A high-risk strategy can be implemented in countries with non-universal screening for VHB. Timely IP plus high-uptake VHB vaccination in infants born to HBsAg-positive mothers was associated with a high immunogenic response and absence of MTCT.

Modifying internal organization and surface morphology of siRNA lipoplexes by sodium alginate addition for efficient siRNA delivery

Vectorized small interfering RNAs (siRNAs) are widely used to induce specific mRNA degradation in the intracellular compartment of eukaryotic cells. Recently, we developed efficient cationic lipid-based siRNA vectors (siRNA lipoplexes or siLex) containing sodium alginate (Nalg-siLex) with superior efficiency and stability properties than siLex. In this study, we assessed the physicochemical and some biological properties of Nalg-siLex compared to siLex. While no significant differences in size, ζ potential and siRNA compaction were detected, the addition of sodium alginate modified the particle morphology, producing smoother and heterogeneous particles characterized by transmission electron microscopy. We also noted that Nalg-siLex have surface differences observed by X-ray photoelectron spectroscopy. These differences could arise from an internal reorganization of components induced by the addition of sodium alginate, that is indicated by Small-Angle X-ray Scattering results. Moreover, Nalg-siLex did not trigger significant hepatotoxicity nor inflammatory cytokine secretion compared to siLex. Taken together these results suggest that sodium alginate played a key role by structuring and reinforcing siRNA lipoplexes, leading to more stable and efficient delivery vector.

Pro-inflammatory M1 macrophages promote Osteogenesis by mesenchymal stem cells via the COX-2-prostaglandin E2 pathway

Bone fractures are among the most common orthopaedic problems that affect individuals of all ages. Immediately after injury, activated macrophages dynamically contribute to and regulate an acute inflammatory response that involves other cells at the injury site, including mesenchymal stem cells (MSCs). These macrophages and MSCs work in concert to modulate bone healing. In this study, we co-cultured undifferentiated M0, pro-inflammatory M1, and anti-inflammatory M2 macrophages with primary murine MSCs in vitro to determine the cross-talk between polarized macrophages and MSCs and their effects on osteogenesis. After 4 weeks of co-culture, MSCs grown with macrophages, especially M1 macrophages, had enhanced bone mineralization compared to MSCs grown alone. The level of bone formation after 4 weeks of culture was closely associated with prostaglandin E2 (PGE2) secretion early in osteogenesis. Treatment with celecoxib, a cyclooxygenase-2 (COX-2) selective inhibitor, significantly reduced bone mineralization in all co-cultures but most dramatically in the M1-MSC co-culture. We also found that the presence of macrophages reduced the secretion of osteoprotegerin (OPG), the decoy RANKL receptor, suggesting that macrophages may indirectly modulate osteoclast activity in addition to enhancing bone formation. Taken together, these findings suggest that an initial pro-inflammatory phase modulated by M1 macrophages promotes osteogenesis in MSCs via the COX-2-PGE2 pathway. Understanding the complex interactions between macrophages and MSCs provide opportunities to optimize bone healing and other regenerative processes via modulation of the inflammatory response. This study provides one possible biological mechanism for the adverse effects of non-steroidal anti-inflammatory drugs on fracture healing and bone regeneration. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:2378-2385, 2017.

Relationships among Bone Quality, Implant Osseointegration, and Wnt Signaling

A variety of clinical classification schemes have been proposed as a means to identify sites in the oral cavity where implant osseointegration is likely to be successful. Most schemes are based on structural characteristics of the bone, for example, the relative proportion of densely compact, homogenous (type I) bone versus more trabeculated, cancellous (type III) bone. None of these schemes, however, consider potential biological characteristics of the bone. Here, we employed multiscale analyses to identify and characterize type I and type III bones in murine jaws. We then combined these analytical tools with in vivo models of osteotomy healing and implant osseointegration to determine if one type of bone healed faster and supported osseointegration better than another. Collectively, these studies revealed a strong positive correlation between bone remodeling rates, mitotic activity, and osteotomy site healing in type III bone and high endogenous Wnt signaling. This positive correlation was strengthened by observations showing that the osteoid matrix that is responsible for implant osseointegration originates from Wnt-responsive cells and their progeny. The potential application of this knowledge to clinical practice is discussed, along with a theory unifying the role that biology and mechanics play in implant osseointegration.

Osteocalcin, under-carboxylated osteocalcin and osteopontin are not associated with gestational diabetes mellitus but are inversely associated with leptin in non-diabetic women

OBJECTIVE

To measure serum osteocalcin (OC), under-carboxylated osteocalcin (ucOC), osteopontin (OPN), and leptin in pregnant women with gestational diabetes mellitus (GDM) and in healthy pregnant women during pregnancy and after birth and relate these markers to glucose metabolism.

METHODS

This was a prospective study including 60 women with GDM and 60 subjects with normal gestation who were evaluated at gestational week 30 and 6 weeks postpartum. Serum OC, ucOC, OPN, leptin, insulin and insulin resistance were evaluated during the study.

RESULTS

Bone biomarkers and leptin were similar between GDM and normal pregnancy. After delivery, OC, ucOC and OPN increased in both groups, while leptin decreased only in healthy controls. Bone markers did not correlate with insulin and insulin resistance in the two groups, but leptin was positively correlated with insulin and insulin resistance and negatively correlated with bone biomarkers only in healthy women. Furthermore, the women who developed diabetes postpartum had lower levels of OC than women with normal glucose tolerance.

CONCLUSION

GDM is not associated with OC, ucOC, OPN, and leptin and does not correlate with insulin resistance. At postpartum, women who develop diabetes have lower osteocalcin concentrations. Leptin correlates with insulin resistance and bone biomarkers in non-diabetic women.

Image reconstruction using electron micrographs of insect flight muscle. Use of thick transverse sections to supplement data from tilted thin longitudinal sections

Three-dimensional reconstruction using electron micrographs of thin sections is a powerful technique for determining cross-bridge structure. Tilt restrictions in the electron microscope prevent data collection beyond tilt angles of 60 degrees, giving rise to a "missing cone" of transform data. We show here how much of this data can be obtained using micrographs of thick transverse sections, and the effect this data has on reconstructed images of the insect flight muscle MYAC layer. As a byproduct, the analysis showed that section thinning resulting from prolonged electron irradiation had occurred in the thin longitudinal section used for the previously published MYAC layer reconstruction (Taylor et al., 1984). Comparison of projection density maps calculated from the thin longitudinal section reconstruction and the thick section data show that the data within the missing cone that is not accessible by tilting sharpens the boundaries of the components, flattens the density profile across the thick filament, and enlarges the molecular envelope of the thin filament. We conclude that the reconstructed images of the MYAC layer provide a picture of the structural principles underlying the system but that transform data within the missing cone are necessary to describe accurately the envelopes and profiles of these structural elements.