Whole-protein enteral nutrition formula supplementation reduces Escherichia and improves intestinal barrier function in HIV-infected immunological nonresponders.

People living with human immunodeficiency virus (PLWH) have persistent malnutrition, intestinal barrier dysfunction, and gut microbial imbalance. The interplay between gut microbiota and nutrients is involved in the immune reconstitution of PLWH. To evaluate the effects of whole-protein enteral nutrition formula supplementation on T-cell levels, intestinal barrier function, nutritional status, and gut microbiota composition in human immunodeficiency virus (HIV)-infected immunological nonresponders (INRs) who failed to normalize CD4+ T-cell counts, with a number <350 cells/µL, a pilot study was carried out in 13 HIV-infected INRs undergoing antiretroviral therapy who received a 3-month phase supplementation of 200 mL/200 kcal/45 g whole-protein enteral nutrition formula once daily. Our primary endpoint was increased CD4+ T-cell counts. Secondary outcome parameters were changes in intestinal barrier function, nutritional status, and gut microbiota composition. We showed that CD4+ T-cell counts of HIV-infected INRs increased significantly after the 3-month supplementation. Dietary supplementation for 3 months improved the intestinal barrier function and nutritional status of HIV-infected INRs. Furthermore, the enteral nutrition formula significantly decreased the relative abundance of Escherichia at the genus level and increased the alpha diversity of gut microbiota in HIV-infected INRs. The findings demonstrated that the whole-protein enteral nutrition formula aids in reducing Escherichia and improving intestinal barrier function in HIV-infected INRs. This study provides insight into the role of nutrients in the improvement of immune reconstitution in HIV-infected INRs. This study is registered in the Chinese Clinical Trial Registry (Document No. ChiCTR2000037839; http://www.chictr.org.cn/index.aspx).

Association between CD4+ T cell counts and gut microbiota and serum cytokines levels in HIV-infected immunological non-responders.

BACKGROUND: CD4+ T cell counts in certain human immunodeficiency virus (HIV)-infected patients called immunological non-responders (INRs) could not return to a normal level even with sustained antiretroviral therapy (ART) because of persistent immune activation, which is associated with pro-inflammatory cytokines production and an altered intestinal microbiome profile. Changes in gut bacterial composition have been linked to low CD4+ T cell counts in HIV-infected individuals. However, the association between CD4+ T cell counts and gut microbiota community composition and cytokines levels in INRs (CD4+ T cell counts < 500 cells/µL) from Yunnan Province, China, has not been previously investigated. METHODS: To address this issue, we carried out a cross-sectional study of 34 HIV-infected INRs. The patients were divided into CD4 count > 200 cells/µL group and CD4 count < 200 cells/µL group. The gut microbiota composition of each subject was analyzed by 16S rRNA gene sequencing. We also compared CD8+ T cell counts, pro-inflammatory cytokines levels, and nutritional status between the two groups. RESULTS: Compared to INRs with CD4 count > 200 cells/µL, those with CD4 count < 200 cells/µL had a lower CD4/CD8 ratio, lower nutritional status and higher serum levels of tumor necrosis factor (TNF)-α, interferon-γ-inducible protein (IP)-10 and interleukin (IL)-1α. Ruminococcaceae was less abundant in the CD4 count < 200 cells/µL group than in the CD4 count > 200 cells/µL group, and difference in alpha diversity was observed between the two groups. Moreover, CD4+ T cell counts were negatively associated with TNF-α and IL-1α levels and positively associated with the relative abundance of Ruminococcaceae. CONCLUSIONS: Our study demonstrated that lower CD4+ T cell counts in INRs are associated with a reduced abundance of Ruminococcaceae in the gut and elevated serum pro-inflammatory cytokines levels. Thus, interventions targeting gut microbiota to increase CD4+ T cell counts are a potential strategy for promoting immune reconstitution in HIV-infected INRs.

Effect of co­culture with amniotic epithelial cells on the biological characteristics of amniotic mesenchymal stem cells.

The aim of the present study was to investigate the effect of co­culture with amniotic epithelial cells (AECs) on the biological characteristics of amniotic mesenchymal stem cells (AMSCs), to compare the expression of C­X­C motif chemokine receptor 4 (CXCR4) in co­cultured AMSCs and to investigate the roles of the stromal cell­derived factor­1 (SDF­1)/CXCR4 axis in the homing and migration of AMSCs. AMSCs were isolated from human amniotic membranes, purified and then differentiated into osteoblasts and adipocytes in vitro, which was verified by von Kossa Staining and Oil Red O staining. Cell viability was measured by Cell Counting kit­8 and trypan blue assays at 24, 48 and 72 h, the expression of CXCR4 was analyzed by immunofluorescence­based flow cytometry and reverse transcription­quantitative polymerase chain reaction, and the migration ability of AMSCs in vitro was observed by a migration assay. The results demonstrated that cell viability (at 48 and 72 h) and survival (at 24, 48 and 72 h) in the co­culture and serum groups were higher compared with the serum­free group. Furthermore, CXCR4 mRNA and protein expression, and migration along the SDF­1 gradient, in the co­culture and serum­free groups were higher compared with the serum group. Overall, the results indicated that AMSCs co­cultured with AECs exhibited enhanced proliferation activity and survival rate. In conclusion, the present study demonstrated that co­culture of AMSCs with AECs upregulated CXCR4 on the surface of AMSCs and enhanced the migration ability of AMSCs in vitro. This result may improve the directional migration and homing ability of AMSCs, as well as provide a theoretical basis for the application of AMSCs in clinical practice as a novel strategy to increase the success of hematopoietic stem cell transplantation.

Dynamics and functions of CD4⁺CD25 (high) regulatory T lymphocytes in Chinese rhesus macaques during the early stage of infection with SIVmac239.

CD4(+)CD25(high) regulatory T cells (Treg), which are a specialized subset of T cells, play an important role in the prevention of autoimmune diseases, maintenance of immune system homeostasis and tolerance to self-antigens. Chinese rhesus macaques (CRMs) are widely used in preclinical research on potential therapeutic drugs, vaccines and mechanisms of human diseases. However, the basic immunological characterization of Treg cells of CRMs has not been well established. To characterize Treg cells, peripheral blood of 43 adult CRMs was analyzed for CD4+ T lymphocytes by flow cytometry. It was found that Treg cells ranged from 1.52% to 11.1% of CD4+ T cells, and the average value was 5.7%. With our SIV-infected CRM model, through further studies, it was found that Treg cells in peripheral blood increased both in relative and absolute quantities. Moreover, Treg cells maintained their functions by suppressing Th1 cytokine secretion of their target cells. The results show that Treg cells might render cellular immunity against SIV viruses dysfunctional during the early stage after infection.

The ß2-microglobulin-free heterodimerization of rhesus monkey MHC class I A with its normally spliced variant reduces the ubiquitin-dependent degradation of MHC class I A.

The MHC class I (MHC I) molecules play a pivotal role in the regulation of immune responses by presenting antigenic peptides to CTLs and by regulating cytolytic activities of NK cells. In this article, we show that MHC I A in rhesus macaques can be alternatively spliced, generating a novel MHC I A isoform (termed "MHC I A-sv1") devoid of α(3) domain. Despite the absence of ß2-microglobulin (ß2m), the MHC I A-sv1 proteins reached the cell surface of K562-transfected cells as endoglycosidase H-sensitive glycoproteins that could form disulfide-bonded homodimers. Cycloheximide-based protein chase experiments showed that the MHC I A-sv1 proteins were more stable than the full-length MHC I A in transiently or stably transfected cell lines. Of particular interest, our studies demonstrated that MHC I A-sv1 could form ß2m-free heterodimers with its full-length protein in mammalian cells. The formation of heterodimers was accompanied by a reduction in full-length MHC I A ubiquitination and consequent stabilization of the protein. Taken together, these results demonstrated that MHC I A-sv1 and MHC I A can form a novel heterodimeric complex as a result of the displacement of ß2m and illustrated the relevance of regulated MHC I A protein degradation in the ß2m-free heterodimerization-dependent control, which may have some implications for the MHC I A splice variant in the fine tuning of classical MHC I A/TCR and MHC I A/killer cell Ig-like receptor interactions.

Dendritic cell subsets dynamics and cytokine production in SIVmac239-infected Chinese rhesus macaques.

BACKGROUND: Several studies have demonstrated that SIV infection progresses more slowly to experimental AIDS in Chinese rhesus macaques (Ch Rhs) than in Indian rhesus macaques (Ind Rhs). Here we investigated the dynamic and functional changes in dendritic cell (DC) subsets in SIVmac239-infected Ch Rhs. RESULTS: The numbers of both mDC and pDC strongly fluctuated but were not significantly changed during the acute and chronic phases of infection. However, the concentration of both poly (I:C)-induced IL-12 and HSV-1-induced IFN-α significantly increased in the acute phase of infection but returned to normal levels at the chronic phase of infection. The peak of IFN-α emerged earlier than that of IL-12, and it had a significantly positive correlation with IL-12, which indicated that IFN-α may initiate the immune activation. We also found that only the concentration of IFN-α was positively correlated with CD4+ T-cell counts, but it was negatively correlated with viral load. CONCLUSION: High levels of IFN-α in the early stage of infection may contribute to effective control of virus replication, and normal levels of IFN-α during chronic infection may help Ch Rhs resist the disease progression. The change in DC subsets dynamics and cytokine production may help further our understanding of why Ch Rhs are able to live longer without progressing to an AIDS-like illness.