Marked Enteropathy in an Accelerated Macaque Model of AIDS.

Enteropathy in HIV infection is not eliminated with combination antiretroviral therapy and is possibly linked to microbial translocation. We used a rapidly progressing SIV/pigtailed macaque model of HIV to examine enteropathy and microbial translocation. Histologic evidence of intestinal disease was observed in only half of infected macaques during late-stage infection (LSI). Combination antiretroviral therapy initiated during acute infection prevented intestinal disease. In the ileum and colon, enteropathy was associated with increased caspase-3 staining, decreased CD3+ T cells, and increased SIV-infected cells. CD3+ T cells were preserved in LSI animals without intestinal disease, and levels of CD3 staining in all LSI animals strongly correlated with the number of infected cells in the intestine and plasma viral load. Unexpectedly, there was little evidence of microbial translocation as measured by soluble CD14, soluble CD163, lipopolysaccharide binding protein, and microbial 16s ribosomal DNA. Loss of epithelial integrity indicated by loss of the tight junction protein claudin-3 was not observed during acute infection despite significantly fewer T cells. Claudin-3 was reduced in LSI animals with severe intestinal disease but did not correlate with increased microbial translocation. LSI animals that did not develop intestinal disease had increased T-cell intracytoplasmic antigen 1-positive cytotoxic T lymphocytes, suggesting a robust adaptive cytotoxic T-lymphocyte response may, in part, confer resilience to SIV-induced intestinal damage.

Molecular detection of Enteropathogens from diarrheic stool of HIV positive patients in Gondar, Ethiopia.

BACKGROUND: Infectious diarrhea is a common problem in the developing world, especially among people living with HIV/AIDS. Traditional diagnostic methods such as stool culture and microscopic examination are limited by resources and poor sensitivity. The use of molecular diagnostics for enteropathogen detection in this region of sub-Saharan Africa has not been fully explored. We sought to identify risk factors and characterize enteropathogens from diarrheic stools of HIV-positive patients in Gondar, Ethiopia using multiplex molecular panels targeting key infectious agents. METHODS: A cross-sectional study of 100 stool samples was performed. Samples were collected consecutively from HIV- positive patients presenting with diarrhea at University of Gondar Hospital clinic, a major center in NW Ethiopia. Genomic DNA was extracted from stool and processed using a multiplex molecular panel Allplex™ [Seegene, Canada]. Correlations between patient characteristics, symptoms, public health risk factors, and enteropathogen type (s) were studied. Eighty-six samples were successfully analyzed by molecular methods. RESULTS: The mean age was 35 with 43% male. Eighty percent lived in an urban area, 18% had access to well water only, and 81% practiced proper hand hygiene. The majority of patients (72%) were receiving HAART with a median CD4 cell count of 362/µL. Multiple pathogens were detected in 94% of specimens, with an average of 5 enteropathogens per sample. Common bacteria, viruses, and parasites detected were Shigella spp./enteroinvasive E. coli (80%), enterotoxigenic E. coli (73%), Norovirus (16%) and B. hominis (62%). CD4 cell count < 500/ µL was associated with the presence of viruses (p = 0.004) and the absence of STEC (p = 0.010). The use of HAART or CD4 levels was not associated with the number of enteropathogens detected. CONCLUSIONS: Diarrheic stool from HIV-positive outpatients in Gondar, Ethiopia had on average 5 enteropathogens present in their stool. Shigellaspp./enteroinvasive E. coli and enterotoxigenic E. coli are the major pathogens, not dissimilar to immunocompetent individuals in low income countries.

Seroepidemiology of hepatitis E virus infection in an urban population in Zambia: strong association with HIV and environmental enteropathy.

BACKGROUND: Hepatitis E virus (HEV) infection causes major epidemics of infectious hepatitis, with high mortality rates in pregnant women. Recent reports indicate that HEV coinfections with human immunodeficiency virus (HIV) may have a more protracted course. However, the impact of HEV infections in communities heavily affected by HIV remains poorly studied. We set out to examine age-related seroprevalence in a community where we have previously carried out studies on environmental enteropathy. METHODS: Blood samples from 194 children and 106 adults were examined for immunoglobulin G and immunoglobulin M antibodies for HEV. HEV data were correlated with HIV status and morphometric analysis of small intestinal biopsies. RESULTS: Seroprevalence rose throughout childhood, from 8% in children aged 1-4 years, to 36% in children aged 10-14 years. In adults, the overall prevalence was 42%, with 28% in HIV-seronegative adults and 71% in HIV-seropositive adults (odds ratio, 6.2; 95% confidence interval, 2.2-18; P = .0001). In adults, villous height and crypt depth measurements showed that HEV seropositivity was associated with worse enteropathy (P = .05 and P = .005, respectively). CONCLUSIONS: HEV infection is common in Zambia. In adults it is strongly associated with HIV status, and also with environmental enteropathy.

Inflammation and epithelial cell injury in AIDS enteropathy: involvement of endoplasmic reticulum stress.

Immunosuppressive lentivirus infections, including human, simian, and feline immunodeficiency viruses (HIV, SIV, and FIV, respectively), cause the acquired immunodeficiency syndrome (AIDS), frequently associated with AIDS enteropathy. Herein, we investigated the extent to which lentivirus infections affected mucosal integrity and intestinal permeability in conjunction with immune responses and activation of endoplasmic reticulum (ER) stress pathways. Duodenal biopsies from individuals with HIV/AIDS exhibited induction of IL-1ß, CD3ε, HLA-DRA, spliced XBP-1(Xbp-1s), and CHOP expression compared to uninfected persons (P<0.05). Gut epithelial cells exposed to HIV-1 Vpr demonstrated elevated TNF-α, IL-1ß, spliced Xbp-1s, and CHOP expression (P<0.05) together with calcium activation and disruption of epithelial cell monolayer permeability. In addition to reduced blood CD4(+) T lymphocyte levels, viral loads in the gut and plasma were high in FIV-infected animals (P<0.05). FIV-infected animals also exhibited a failure to gain weight and increased lactulose/mannitol ratios compared with uninfected animals (P<0.05). Proinflammatory and ER stress gene expression were activated in the ileum of FIV-infected animals (P<0.05), accompanied by intestinal epithelial damage with loss of epithelial cells and leukocyte infiltration of the lamina propria. Lentivirus infections cause gut inflammation and ensuing damage to intestinal epithelial cells, likely through induction of ER stress pathways, resulting in disruption of gut functional integrity.

Small intestine CD4+ cell reduction and enteropathy in simian/human immunodeficiency virus KS661-infected rhesus macaques in the presence of low viral load.

Human immunodeficiency virus type 1, simian immunodeficiency virus and simian/human immunodeficiency virus (SHIV) infection generally lead to death of the host accompanied by high viraemia and profound CD4(+) T-cell depletion. SHIV clone KS661-infected rhesus macaques with a high viral load set point (HVL) ultimately experience diarrhoea and wasting at 6-12 months after infection. In contrast, infected macaques with a low viral load set point (LVL) usually live asymptomatically throughout the observation period, and are therefore referred to as asymptomatic LVL (Asym LVL) macaques. Interestingly, some LVL macaques exhibit diarrhoea and wasting similar to the symptoms of HVL macaques and are termed symptomatic LVL (Sym LVL) macaques. This study tested the hypothesis that Sym LVL macaques have the same degree of intestinal abnormalities as HVL macaques. The proviral DNA loads in lymphoid tissue and the intestines of Sym LVL and Asym LVL macaques were comparable and all infected monkeys showed villous atrophy. Notably, the CD4(+) cell frequencies of lymphoid tissues and intestines in Sym LVL macaques were remarkably lower than those in Asym LVL and uninfected macaques. Furthermore, Sym LVL and HVL macaques exhibited an increased number of activated macrophages. In conclusion, intestinal disorders including CD4(+) cell reduction and abnormal immune activation can be observed in SHIV-KS661-infected macaques independent of virus replication levels.

Special histologic stains are rarely beneficial for the evaluation of HIV-related gastrointestinal infections.

During a 28-month period, endoscopic mucosal biopsy specimens from all HIV-infected patients were submitted for routine histologic evaluation. Immunoperoxidase staining for cytomegalovirus and herpesvirus antigens (esophagus), mycobacterial and fungal staining, and Gram staining of mucosal biopsy specimens were done. Special fungal and acid-fast stains were selectively performed in patients with absolute CD4 cell counts of less than 200 cells per microliter (200 x 10(6)/L) and/or with diarrhea and or wasting syndrome. Treatment was based on the endoscopic and histologic findings, and long-term follow-up was performed. The 121 symptomatic HIV-infected patients underwent 221 upper and/or lower endoscopies with 285 biopsy sites. The sensitivity and specificity of H&E staining for the diagnosis of gastrointestinal cytomegalovirus were 97% and 100%, respectively. The results of fungal and mycobacterial stains neither altered therapy nor identified previously undiagnosed infections in any patient. Long-term follow-up revealed no patient in whom an infection was missed on routine H&E, which affected outcome. Routine H&E staining is accurate for the diagnosis of gastrointestinal opportunistic infections in HIV-infected patients. Special histologic stains for fungal, mycobacterial, and viral infections did not increase the diagnostic yield or alter medical therapy but doubled the costs.

HIV enteropathy: comparative morphometry of the jejunal mucosa of HIV infected patients resident in the United Kingdom and Uganda.

AIMS: To compare jejunal mucosal morphometry in HIV infected patients resident in London and Uganda. PATIENTS: Twenty HIV positive patients from London and 16 from Uganda were studied, and compared with HIV negative control subjects from both sites. METHODS: Stools and biopsy specimens were examined for enteropathogens. Surface area to volume (S:V) ratio was estimated morphometrically, mean crypt length of jejunal biopsy specimens was measured, and HIV infected cells detected immunohistochemically were quantified. RESULTS: Enteric pathogens were detected in none of the London patients, and in three Ugandan patients. S:V ratio was lower, and mean crypt length higher, in the specimens of London patients than in normal subjects, but there was no difference in S:V ratio or mean crypt length between Ugandan patients and controls. A negative correlation was present between S:V ratio and mean crypt length in all biopsy specimens analysed. HIV infected cells were detected only in lamina propria. CONCLUSION: Infection of cells in the lamina propria of the jejunum with HIV stimulates crypt cell proliferation, and a fall in villous surface area. The mucosal response to HIV is masked by other pathogens in the African environment.

Enteric viral infections as a cause of diarrhoea in the acquired immunodeficiency syndrome.

BACKGROUND AND AIMS: The role of non-cytomegalovirus (CMV) enteric viral infection in causing diarrhoea in patients with human immunodeficiency virus (HIV) is poorly understood. We aimed to investigate the prevalence of these infections in acute and chronic diarrhoea. METHODS: Stool specimens from 377 HIV-infected patients presenting with diarrhoea were studied prospectively for evidence of non-CMV enteric viral infection. Patients with diarrhoea underwent investigation for gastrointestinal pathogens, including electron microscopic examination of stool for enteric viruses. We collected data on patients in whom enteric virus was identified and examined the association of enteric virus infection with diarrhoeal symptomatology. RESULTS: Eighty-nine (10.3%) stool specimens from 60 (15.9%) HIV+ individuals were positive for coronavirus (n = 13, 22%), rotavirus (n = 11, 18%), adenovirus (n = 30, 50%) and small round structured viruses (n = 5, 8%) or dual infection (n = 2, 3%). Thirty-four of 52 (65%) patients available for analysis had acute diarrhoea, and 18/52 (35%) had chronic diarrhoea. Twenty-three of 52 (44%) patients had a concurrent gut pathogen. After exclusion of concurrent pathogens enteric viral infections were found to be significantly associated with acute as opposed to chronic diarrhoea (P = 0.004). The presence of adenovirus colitis was significantly more likely to be associated with chronic diarrhoea (15/21 cases) than adenovirus isolated from stool alone (9/23 cases) (P = 0.03). There was a trend towards an association between adenovirus colitis and colonic cytomegalovirus infection (P = 0.06). CONCLUSION: Enteric viral infection is strongly associated with acute diarrhoea in patients with HIV. Light microscopic examination of large bowel biopsies can identify adenovirus colitis which is significantly associated with chronic diarrhoea, and in addition may facilitate gastrointestinal co-infection with CMV.

Phenotypic variations and switches in HIV isolated from the blood and the gastrointestinal tissues of patients with HIV-1 infection. HIV/GI Research Study Group.

The objective of this study was to determine the initial and subsequent phenotypes of HIV-1 isolated from the blood, duodenal, and colonic biopsies of 51 HIV-1 positive patients followed prospectively over 2 years. Blood and tissues were cocultured with stimulated peripheral blood monocytes, and HIV was analyzed for phenotypic expression of syncytia-induction (SI). A total of 45/51 patients had HIV-1 isolated from the blood and 35/51 had HIV isolated from gastrointestinal tract. In 12/45 patients SI-HIV-1 was isolated from the blood. In 6/12 patients the blood phenotype reverted to the NSI phenotype. SI phenotypes were also isolated from the colon and duodenum of 8/35 patients and reversion from SI to NSI virus phenotype was again observed in gut tissue of 3/8 patients. These results show that gastrointestinal tissues can harbor SI HIV phenotype. Discordant phenotypes can be found in tissue and blood of late-stage patients. Reversion of phenotypic SI expression to NSI may occur in patients receiving monotherapy as antiretroviral treatment. These results suggest that gastrointestinal tissues may act as a separate and distinct site involved in HIV replication and its associated pathogenesis.