Publications

INTRODUCTION

GeneXpert® MTB/RIF (Xpert) is now widely distributed in high human immunodeficiency virus (HIV)/tuberculosis (TB)-burden countries. Yet, whether the test improves patient-important outcomes within HIV treatment programs in limited resource settings is unknown.

METHODS

To investigate whether use of Xpert for TB screening prior to initiation of antiretroviral treatment (ART) improves patient-important outcomes, in a pragmatic randomized controlled trial we assigned 424 patients to Xpert or fluorescence sputum smear microscopy (FM) at ART initiation. The primary endpoint was a composite of 3-month mortality and ART-associated TB.

RESULTS

There was no difference in overall TB diagnosis at ART initiation (20% [n = 43] Xpert vs 21% [n = 45] FM; P = .80), with most patients in both groups treated empirically. There was no difference in time to TB treatment initiation {5 days (interquartile range [IQR], 3-13) vs 8 days [IQR, 3-23; P = .26]} or loss to follow-up (32 [15%] vs 38 [18%]; P = 0.38). Although a nonsignificant reduction in mortality occurred in the Xpert group (11 [6%] vs 17 [10%]; 95% CI, -9% to 2%; P = .19), there was no difference in the composite outcome (9% [n = 17] Xpert vs 12% [n = 21] FM; difference -3%; 95% CI, -9% to 4%).

CONCLUSIONS

Among HIV-infected initiating ART, centralized TB screening with Xpert did not reduce the rate of ART-associated TB and mortality, compared with fluorescence microscopy.

Highly potent broadly neutralizing human monoclonal antibodies hold promise for HIV prophylaxis and treatment. We used the SCID-hu Thy/Liv and BLT humanized mouse models to study the efficacy of these antibodies, primarily PG16, against HIV-1 clades A, B, and C. PG16 targets a conserved epitope in the V1/V2 region of gp120 common to 70-80% of HIV-1 isolates from multiple clades and has extremely potent in vitro activity against HIVJR-CSF. PG16 was highly efficacious in SCID-hu mice as a single intraperitoneal administration the day before inoculation of R5-tropic HIV directly into their Thy/Liv implants and demonstrated even greater efficacy if PG16 administration was continued after Thy/Liv implant HIV inoculation. However, PG16 as monotherapy had no activity in humanized mice with established R5-tropic HIV infection. These results provide evidence of tissue penetration of the antibodies, which could aid in their ability to prevent infection if virus crosses the mucosal barrier.

Organic cation transporter 1, OCT1 (SLC22A1), is the major hepatic uptake transporter for metformin, the most prescribed antidiabetic drug. However, its endogenous role is poorly understood. Here we show that similar to metformin treatment, loss of Oct1 caused an increase in the ratio of AMP to ATP, activated the energy sensor AMP-activated kinase (AMPK), and substantially reduced triglyceride (TG) levels in livers from healthy and leptin-deficient mice. Conversely, livers of human OCT1 transgenic mice fed high-fat diets were enlarged with high TG levels. Metabolomic and isotopic uptake methods identified thiamine as a principal endogenous substrate of OCT1. Thiamine deficiency enhanced the phosphorylation of AMPK and its downstream target, acetyl-CoA carboxylase. Metformin and the biguanide analog, phenformin, competitively inhibited OCT1-mediated thiamine uptake. Acute administration of metformin to wild-type mice reduced intestinal accumulation of thiamine. These findings suggest that OCT1 plays a role in hepatic steatosis through modulation of energy status. The studies implicate OCT1 as well as metformin in thiamine disposition, suggesting an intriguing and parallel mechanism for metformin and its major hepatic transporter in metabolic function.

Development of the vascular disease pulmonary hypertension (PH) involves disparate molecular pathways that span multiple cell types. MicroRNAs (miRNAs) may coordinately regulate PH progression, but the integrative functions of miRNAs in this process have been challenging to define with conventional approaches. Here, analysis of the molecular network architecture specific to PH predicted that the miR-130/301 family is a master regulator of cellular proliferation in PH via regulation of subordinate miRNA pathways with unexpected connections to one another. In validation of this model, diseased pulmonary vessels and plasma from mammalian models and human PH subjects exhibited upregulation of miR-130/301 expression. Evaluation of pulmonary arterial endothelial cells and smooth muscle cells revealed that miR-130/301 targeted PPARγ with distinct consequences. In endothelial cells, miR-130/301 modulated apelin-miR-424/503-FGF2 signaling, while in smooth muscle cells, miR-130/301 modulated STAT3-miR-204 signaling to promote PH-associated phenotypes. In murine models, induction of miR-130/301 promoted pathogenic PH-associated effects, while miR-130/301 inhibition prevented PH pathogenesis. Together, these results provide insight into the systems-level regulation of miRNA-disease gene networks in PH with broad implications for miRNA-based therapeutics in this disease. Furthermore, these findings provide critical validation for the evolving application of network theory to the discovery of the miRNA-based origins of PH and other diseases.

Preventing mucosal transmission of HIV is critical to halting the HIV epidemic. Novel approaches to preventing mucosal transmission are needed. Hyaluronic acid (HA) is a major extracellular component of mucosa and the primary ligand for the cell surface receptor CD44. CD44 enhances HIV infection of CD4(+) T cells, but the role of HA in this process is not clear. To study this, virions were generated with CD44 (HIVCD44) or without CD44 (HIVmock). Exogenous HA reduced HIV infection of unstimulated CD4(+) T cells in a CD44-dependent manner. Conversely, hyaluronidase-mediated reduction of endogenous HA on the cell surface enhanced HIV binding to and infection of unstimulated CD4(+) T cells. Exogenous HA treatment reduced activation of protein kinase C alpha via CD44 on CD4(+) T cells during infection with HIVCD44. These results reveal new roles for HA during the interaction of HIV with CD4(+) T cells that may be relevant to mucosal HIV transmission and could be exploitable as a future strategy to prevent HIV infection.

BACKGROUND

The T594M variant of the β-subunit of the sodium epithelial channel (ENaC) gene may contribute to hypertension in individuals of Indo-Aryan origin.

METHODS

Present study was performed to assess the role of the ENaC gene variant as an independent risk factor for hypertension in subjects of Indo-Aryan ancestry. A total of 150 patients of recently detected essential hypertension and 150 matched controls were genotyped for the T594M polymorphism of the ENaC gene by PCR-RFLP method.

RESULTS

β-T594M mutation was found to be non-polymorphic. There was major genotype call in both the groups i.e. cases and controls. Other phenotypic parameters like age, sex and body mass index were also similar among hypertensive patients and controls (P > 0.05). Hypertensive patients had significantly higher total cholesterol and triglycerides compared with controls (P < 0.0001).

CONCLUSION

These results do not suggest an important role for the T594M variant of the ENaC gene contributing to either the development or severity of hypertension in subjects of Indo-Aryan ancestry.