Faculty Bibliography

BACKGROUND AND IMPORTANCE/BACKGROUND:Pseudotumor cerebri and Chiari I malformation are found to coexist in a subset of patients. Surgical cranial decompression has been the mainstay of Chiari malformation management, whereas venous sinus stenting has emerged as an effective treatment modality for pseudotumor cerebri. Gaps in our current understanding of cerebrospinal fluid (CSF) circulation and the pathophysiology behind CSF-related disorders present difficulties in the simultaneous management of these conditions. A case is presented of the successful management of both conditions with venous sinus stenting, with sustained improvement in symptoms and structural abnormalities of the Chiari malformation and associated syrinxes. CLINICAL PRESENTATION/METHODS:An obese woman in her 20s with a history of occipital headaches who presented with progressively worsening intermittent visual obscurations was diagnosed with pseudotumor cerebri, Chiari I malformation, and associated spinal syrinxes. Magnetic resonance venography demonstrated right transverse sinus narrowing with an elevated pressure gradient. Successful endovascular intervention with venous sinus stenting achieved normalization of the venous sinus pressure gradient and symptomatic improvement. After stenting, the cervical syrinx was observed to have decreased in size, with a decrease in the extent of cerebellar tonsillar herniation and an increase in CSF signal around the cerebellar tonsils. CONCLUSION/CONCLUSIONS:Venous sinus stenting for treatment of concomitant pseudotumor cerebri and Chiari I malformation can be effective in patients demonstrating transverse sinus stenosis.

Effective antiretroviral therapy (ART) dramatically reduces AIDS-related complications, yet the life expectancy of long-term ART-treated HIV-infected patients remains shortened compared to that of uninfected controls, due to increased risk of non-AIDS related morbidities. Many propose that these complications result from translocated microbial products from the gut that stimulate systemic inflammation--a consequence of increased intestinal paracellular permeability that persists in this population. Concurrent intestinal immunodeficiency and structural barrier deterioration are postulated to drive microbial translocation, and direct evidence of intestinal epithelial breakdown has been reported in untreated pathogenic SIV infection of rhesus macaques. To assess and characterize the extent of epithelial cell damage in virally-suppressed HIV-infected patients, we analyzed intestinal biopsy tissues for changes in the epithelium at the cellular and molecular level. The intestinal epithelium in the HIV gut is grossly intact, exhibiting no decreases in the relative abundance and packing of intestinal epithelial cells. We found no evidence for structural and subcellular localization changes in intestinal epithelial tight junctions (TJ), but observed significant decreases in the colonic, but not terminal ileal, transcript levels of TJ components in the HIV+ cohort. This result is confirmed by a reduction in TJ proteins in the descending colon of HIV+ patients. In the HIV+ cohort, colonic TJ transcript levels progressively decreased along the proximal-to-distal axis. In contrast, expression levels of the same TJ transcripts stayed unchanged, or progressively increased, from the proximal-to-distal gut in the healthy controls. Non-TJ intestinal epithelial cell-specific mRNAs reveal differing patterns of HIV-associated transcriptional alteration, arguing for an overall change in intestinal epithelial transcriptional regulation in the HIV colon. These findings suggest that persistent intestinal epithelial dysregulation involving a reduction in TJ expression is a mechanism driving increases in colonic permeability and microbial translocation in the ART-treated HIV-infected patient, and a possible immunopathogenic factor for non-AIDS related complications.