Evaluation of HIV protease and nucleoside reverse transcriptase inhibitors on proliferation, necrosis, apoptosis in intestinal epithelial cells and electrolyte and water transport and epithelial barrier function in mice

Adults on pre-exposure prophylaxis (tenofovir-emtricitabine) have faster clearance of anti-HIV monoclonal antibody VRC01

Broadly neutralizing monoclonal antibodies (mAbs) are being developed for HIV-1 prevention. Hence, these mAbs and licensed oral pre-exposure prophylaxis (PrEP) (tenofovir-emtricitabine) can be concomitantly administered in clinical trials. In 48 US participants (men and transgender persons who have sex with men) who received the HIV-1 mAb VRC01 and remained HIV-free in an antibody-mediated-prevention trial (ClinicalTrials.gov #NCT02716675), we conduct a post-hoc analysis and find that VRC01 clearance is 0.08 L/day faster (p = 0.005), and dose-normalized area-under-the-curve of VRC01 serum concentration over-time is 0.29 day/mL lower (p < 0.001) in PrEP users (n = 24) vs. non-PrEP users (n = 24). Consequently, PrEP users are predicted to have 14% lower VRC01 neutralization-mediated prevention efficacy against circulating HIV-1 strains. VRC01 clearance is positively associated (r = 0.33, p = 0.03) with levels of serum intestinal Fatty Acid Binding protein (I-FABP), a marker of epithelial intestinal permeability, which is elevated upon starting PrEP (p = 0.04) and after months of self-reported use (p = 0.001). These findings have implications for the evaluation of future HIV-1 mAbs and postulate a potential mechanism for mAb clearance in the context of PrEP.

Viral infections in inflammatory bowel disease: Tips and tricks for correct management

Over the past decades, the treatment of inflammatory bowel diseases (IBD) has become more targeted, anticipating the use of immune-modifying therapies at an earlier stage. This top-down approach has been correlated with favorable short and long-term outcomes, but it has also brought with it concerns regarding potential infectious complications. This large IBD population treated with immune-modifying therapies, especially if combined, has an increased risk of severe infections, including opportunistic infections that are sustained by viral, bacterial, parasitic, and fungal agents. Viral infections have emerged as a focal safety concern in patients with IBD, representing a challenge for the clinician: they are often difficult to diagnose and are associated with significant morbidity and mortality. The first step is to improve effective preventive strategies, such as applying vaccination protocols, adopt adequate prophylaxis and educate patients about potential risk factors. Since viral infections in immunosuppressed patients may present atypical signs and symptoms, the challenges for the gastroenterologist are to suspect, recognize and diagnose such complications. Appropriate treatment of common viral infections allows us to minimize their impact on disease outcomes and patients’ lives. This practical review supports this standard of care to improve knowledge in this subject area.

Antiretroviral Therapy Administration in Healthy Rhesus Macaques Is Associated with Transient Shifts in Intestinal Bacterial Diversity and Modest Immunological Perturbations

Gastrointestinal (GI) immune system competency is dependent upon interactions with commensal microbiota, which can be influenced by wide-ranging pharmacologic interventions. In simian immunodeficiency virus (SIV)-infected Asian macaque models of human immunodeficiency virus (HIV) infection, we previously noted that initiation of antiretroviral therapy (ART) is associated with a specific imbalance (dysbiosis) of the composition of the intestinal bacteriome. To determine if ART itself might contribute to dysbiosis or immune dysfunction, we treated healthy rhesus macaques with protease, integrase, or reverse transcriptase inhibitors for 1 to 2 or for 5 to 6 weeks and evaluated intestinal immune function and the composition of the fecal bacterial microbiome. We observed that individual antiretrovirals (ARVs) modestly altered intestinal T-cell proinflammatory responses without disturbing total or activated T-cell frequencies. Moreover, we observed transient disruptions in bacterial diversity coupled with perturbations in the relative frequencies of bacterial communities. Shifts in specific bacterial frequencies were not persistent posttreatment, however, with individual taxa showing only isolated associations with T-cell proinflammatory responses. Our findings suggest that intestinal bacterial instability and modest immunological alterations can result from ART itself. These data could lead to therapeutic interventions which stabilize the microbiome in individuals prescribed ART.IMPORTANCE Dysbiosis of the fecal microbiome is a common feature observed in ARV-treated people living with HIV. The degree to which HIV infection itself causes this dysbiosis remains unclear. Here, we demonstrate that medications used to treat HIV infection can influence the composition of the GI tract immune responses and its microbiome in the nonhuman primate SIV model.

Persistent diarrhoea: current knowledge and novel concepts

BACKGROUND

Persistent diarrhoea (PD), defined as diarrhoeal symptoms for longer than 2 weeks, still forms a substantial disease burden in children under 5 years of age. This article provides an overview of the current knowledge of PD and discusses novel concepts.

METHODS

A literature search on PD was performed which focused on evidence on epidemiology, pathophysiology and management of the disease.

RESULTS

The prevalence of PD has potentially decreased over the last decades. Debate remains around the role of specific bacterial, viral and parasitic infections with PD. PD is associated with malnutrition and a compromised immune system, including that caused by HIV infection. Management includes fluid resuscitation and improving nutritional status. There is a lack of evidence on the use of antibiotic therapy for PD. There is increasing interest in nutrient-based interventions, including pre- and/or probiotics that can modify the microbiome and thereby potentially prevent or improve the outcome of PD in children.

CONCLUSION

As PD remains a significant health burden, multicentre clinical trials are needed to inform future treatment guidelines.

ABBREVIATIONS

PD, persistent diarrhoea; EED, environmental enteric dysfunction; IBD, inflammatory bowel disease; WHO, World Health Organization.

Common Gastrointestinal Complications Associated with Human Immunodeficiency Virus/AIDS: An Overview

Highly active antiretroviral therapy (HAART) has transformed human immunodeficiency virus (HIV)/AIDS into a manageable chronic illness. People living with HIV/AIDS (PLWHA) can experience multiple physical symptoms or problems related to HIV infection and treatment. A common problem for PLWHA continues to be diarrhea and nausea and vomiting (NV). Diarrhea and NV can negatively impact the quality of life and adherence to medication therapy among PLWHA and are common reasons to change or discontinue HAART regimens. Because diarrhea and NV can have substantial negative health outcomes for PLWHA, it is important to understand the causes of these conditions.

HIV and diarrhoea: what is new?

PURPOSE OF REVIEW

The review examines the changing causes and the investigation of infectious and noninfectious diarrhoea in individuals with HIV.

RECENT FINDINGS

Despite the excellent prognosis conferred by combination antiretroviral therapy, diarrhoea is still common in HIV-positive individuals and is associated with reduced quality of life and survival. There is increasing interest in the importance of Th17 and Th22 T cells in the maintenance of mucosal immunity within the gut, and in the role of the gut microbiome in gut homeostasis. Bacterial causes of HIV-associated diarrhoea continue to be important in resource-poor settings. In other settings, sexually transmitted enteric infections such as lymphogranuloma venereum and shigellosis are increasingly reported in men who have sex with men. HIV increases the risk of such infections and the presence of antimicrobial resistance. Parasitic causes of diarrhoea are more common in individuals with uncontrolled HIV and low CD4 counts. Noninfectious causes of diarrhoea include all classes of antiretroviral therapy, which is under-recognised as a cause of poor treatment adherence. Pancreatic dysfunction is remediable and the diagnostic workup of HIV-related diarrhoea should include faecal elastase measurements. New antimotility agents such as crofelemer may be useful in managing secretory diarrhoea symptoms.

SUMMARY

Clinicians looking after patients with HIV should ask about diarrhoeal symptoms, which are under-reported and may have a remediable infectious or noninfectious cause.

Mucin secreting cells in the stomach and colon are altered by combination antiretroviral treatment in an obese rat model

Mucins, secreted by intestinal goblet cells, form an integral part of the intestinal biofilm, which is important for the functioning of a healthy gastrointestinal tract (GIT). This mucous layer is sensitive to factors such as diet, drugs and inflammation. Histochemically, mucins can be classified as neutral or acidic, where acidic mucins can contain sulphate groups (sulphomucins) or sialic acid (sialomucins). The aim of the present study was to determine the composition of various mucin secreting cells using histochemical stains in rats fed on a high calorie diet (HCD) treated with antiretroviral therapy (ART). Wistar rats (N=24) were divided into a lean control group (C/ART-), high calorie diet group (C/HCD+), ART group (C/ART+) and HCD and ART group (HCD+/ART+). The body of the stomach as well as the colon were stained with Alcian Blue Periodic Schiff (ABPAS) to distinguish between neutral and acidic mucins and Alcian Blue Aldehyde Fuschin (ABAF) to distinguish between sialo-and sulphomucins. An increase of the total gastric mucous cells was observed in the HCD+/ART+ group compared to the C/ART- group using both ABPAS and ABAF. A decrease of neutral cells in the distal part of the colonic crypts in the C/HCD+ and C/ART+ groups compared to the C/ART- group were observed. Mixed goblet cells in the colonic crypts of the C/ART- and HCD+/ART+ groups were decreased in comparison to the C/ART+ group. The study showed that the total mean percentage of mucous cells in the stomach as well as the total amount of neutral goblet cells in the colon were most affected by ART and a HCD. These changes in a rat model suggest that the quality of the biofilm may be altered and should be considered when ART is prescribed to obese patients.

Assessment of the Intestinal Barrier with Five Different Permeability Tests in Healthy C57BL/6J and BALB/cJ Mice

BACKGROUND

Intestinal permeability is thought to be of major relevance for digestive and nutrition-related diseases, and therefore has been studied in numerous mouse models of disease. However, it is unclear which tools are the preferable ones, and how normal values should be defined.

AIMS

To compare different in vivo permeability tests in healthy mice of commonly used genetic backgrounds.

METHODS

We assessed the intestinal barrier in male and female C57BL/6J and BALB/cJ mice of different ages, using four orally administered permeability markers, FITC-dextran 4000 (FITC-D4000) and ovalbumin (OVA) measured in plasma, and polyethylene glycol (PEG) and lactulose/mannitol (Lac/Man) measured in urine, and by assessing lipopolysaccharide (LPS) in portal vein plasma.

RESULTS

After gavage, FITC-D4000, OVA, Lac/Man, and PEG400, but not PEG4000, were detectable in plasma or urine. Female mice tended to have a higher permeability according to the FITC-D4000, OVA, and PEG400 tests, but the Lac/Man ratio was higher in males. No significant differences between the two mouse strains of young and old mice were observed except for mannitol recovery, which was higher in BALB/cJ mice compared to C57BL/6J mice (p < 0.05). Virtually no LPS was detected in healthy mice. For all markers, normal values have been defined based on 5th-95th percentile ranges of our data.

CONCLUSION

Selected oral permeability tests, such as FITC-D4000, OVA, PEG400, and Lac/Man, as well as LPS measurements in portal vein plasma, could be suitable for the evaluation of the intestinal barrier in mice, if used in a standardized way.

Crofelemer for the symptomatic relief of non-infectious diarrhea in adult patients with HIV/AIDS on anti-retroviral therapy

Chronic diarrhea remains a common condition that affects people infected with human immunodeficiency virus (HIV) despite the widespread use of potent antiretroviral therapy. It is important that providers control this condition, as the persistence of diarrhea affects the quality of life of patients and may contribute to decreased adherence to antiretroviral therapy. Strategies to control diarrhea in patients with HIV infection include switching to a new antiretroviral regimen and/or the use of specific medications to control the diarrhea. This review aims to provide a concise evaluation of a newly approved medication (crofelemer) that has a novel mechanism of action and has received approval for the symptomatic relief of non-infectious diarrhea in adult patients with HIV on anti-retroviral therapy.

Human Immunodeficiency Virus-Associated Diarrhea: Still an Issue in the Era of Antiretroviral Therapy

Over half of patients with human immunodeficiency virus (HIV) experience diarrhea that contributes negatively to quality of life and adherence to antiretroviral therapy (ART). Opportunistic infectious agents that cause diarrhea in patients with HIV span the array of protozoa, fungi, viruses, and bacteria. With global use of ART, the incidence of diarrhea because of opportunistic infections has decreased; however, the incidence of noninfectious diarrhea has increased. The etiology of noninfectious diarrhea in patients with HIV is multifactorial and includes ART-associated diarrhea and gastrointestinal damage related to HIV infection (i.e., HIV enteropathy). A basic algorithm for the diagnosis of diarrhea in patients with HIV includes physical examination, a review of medical history, assessment of HIV viral load and CD4+ T cell count, stool microbiologic assessment, and endoscopic evaluation, if needed. For patients with negative diagnostic results, the diagnosis of noninfectious diarrhea may be considered. Pharmacologic options for the treatment of noninfectious diarrhea are primarily supportive; however, the use of many unapproved agents is based on unstudied and anecdotal information. In addition, these agents can be associated with treatment-limiting adverse events (AEs), such as drug-drug interactions with ART regimens, abuse liability, and additional gastrointestinal AEs. Currently, crofelemer, an antisecretory agent, is the only therapy approved in the USA for the symptomatic relief of noninfectious diarrhea in patients with HIV on ART.

Association of circulating cytochrome c with clinical manifestations of antiretroviral-induced toxicity

Diagnosis of antiretroviral therapy (ART) toxicity is complicated. Apoptosis has been implicated in ART toxicity. Cytochrome c (Cyt-C) is a mitochondrial protein found in plasma during pro-apoptotic states. We conducted a study of HIV-infected individuals on ART with (cases, n=21) and without (controls, n=21) clinical evidence of toxicity to determine if elevated plasma Cyt-C is associated with ART toxicity. When corrected for CD4 count, viral load, and duration of HIV infection, cases are 7.86 times more likely than controls to have plasma Cyt-C>0.216 ng/mL. Cyt-C could be a useful clinical tool to guide treatment decisions in this population.

Noninfectious Diarrhea in HIV Seropositive Individuals: a Review of Prevalence Rates, Etiology, and Management in the Era of Combination Antiretroviral Therapy

Introduction

Diarrhea poses a substantial burden for patients with human immunodeficiency virus (HIV), negatively impacting quality-of-life (QoL) and adherence to antiretroviral therapy. During the combination antiretroviral therapy (cART) era, as incidence of opportunistic infection as a cause of diarrhea decreased, incidence of noninfectious diarrhea (including diarrhea as an adverse event [AE] of cART and HIV enteropathy) increased proportionately. A literature search was conducted for information on prevalence, etiology, and treatment options for noninfectious diarrhea in patients with HIV.

Results

For marketed antiretroviral therapies, up to 28% of patients live with >4 loose or watery stools per day. The US Food and Drug Administration (FDA) does not require pharmaceutical manufacturers to include, within approved prescribing information, prevalence rates for all grades of diarrhea. Traditionally, noninfectious diarrhea management focused on avoiding use of diarrhea-associated cART; symptom management (nonpharmacologic and/or pharmacologic); and, as a last resort, changing cART. Examining the evidence upon which this approach is based reveals that most strategies rely upon anecdotal information and case reports. This review summarizes the literature and updates clinicians on the most recent options for management of noninfectious diarrhea in patients with HIV.

Conclusion

Diarrhea in patients with HIV is a significant unmet clinical need that contributes to worsening QoL and complicates medical management. Approaching management using a stepwise method of nonpharmacologic (diet), nonprescription (over-the-counter) and, finally, prescription agent changes (modification of cART or addition of an evidence-based antidiarrheal) appears reasonable, despite a lack of clear scientific evidence to support the initial two steps of this approach. If diet modifications, including psyllium and fiber introduction, fail to resolve noninfectious diarrhea in patients with HIV, loperamide followed by crofelemer should be considered. Clinicians are encouraged to review the most recent literature, not rely upon prescribing information. Continued vigilance by HIV providers to the presence of gastrointestinal AEs, even in patients taking the most recently approved antiretroviral agents, is warranted. Additional research is justified in identifying the etiology and management of HIV-associated diarrhea in patients on successful cART regimens.

Electronic supplementary material

The online version of this article (doi:10.1007/s40121-014-0047-5) contains supplementary material, which is available to authorized users.

HIV protease inhibitors in gut barrier dysfunction and liver injury

The development of HIV protease inhibitors (HIV PIs) has been one of the most significant advances of the past two decades in controlling HIV infection. HIV PIs have been used successfully in highly active anti-retroviral therapy (HAART) for HIV infection, which is currently the most effective treatment available. Incorporation of HIV PIs in HAART causes profound and sustained suppression of viral replication, significantly reduces the morbidity and mortality of HIV infection, and prolongs the lifespan of HIV patients. However, in the era of HAART, drug-induced gastrointestinal (GI) side effects and hepatotoxicity have emerged as important potential complications of HIV therapy, particularly those regimens containing HIV PIs. In this mini-review, we highlight the current understanding of the mechanisms of HIV PI-associated GI and liver injury.

Crofelemer, a novel agent for treatment of non-infectious diarrhea in HIV-infected persons

Crofelemer is the first US FDA-approved drug for symptomatic relief in HIV-infected persons on antiretroviral therapy (ART) who have non-infectious diarrhea. With the availability of ART, there is increased survival and decrease in gastrointestinal opportunistic infections. However, diarrhea secondary to ART and HIV enteropathy is common in HIV-infected persons. Crofelemer is manufactured from the red latex sap of the Croton lechleri tree in South America. It has a unique mechanism leading to inhibition of chloride ion secretion by blocking chloride channels in the gastrointestinal lumen. This reduces efflux of sodium and water, which in turn reduces the frequency and consistency of diarrhea. Crofelemer is well tolerated due to minimal systemic absorption and has a good safety profile. The availability of crofelemer will likely have a positive impact on the quality of life in HIV-infected persons and also increase compliance to ART.

Crofelemer for the treatment of chronic diarrhea in patients living with HIV/AIDS

Diarrhea is a common comorbidity present in patients with human immunodeficiency virus/acquired immune deficiency syndrome (HIV/AIDS) who are treated with highly active antiretroviral therapy. With a multifactorial etiology, this diarrhea often becomes difficult to manage. In addition, some antiretrovirals are associated with chronic diarrhea, which potentially creates an adherence barrier to antiretrovirals and may ultimately affect treatment outcomes and future therapeutic options for HIV. A predominant type of diarrhea that develops in HIV patients has secretory characteristics, including increased secretion of chloride ions and water into the intestinal lumen. One proposed mechanism that may lead to this type of secretory diarrhea is explained by the activation of the cystic fibrosis transmembrane conductance regulator and calcium-activated chloride channels. Crofelemer is a novel antidiarrheal agent that works by inhibiting both of these channels. The efficacy and safety of crofelemer has been evaluated in clinical trials for various types of secretory diarrhea, including cholera-related and acute infectious diarrhea. More recently, crofelemer was approved by the US Food and Drug Administration for the symptomatic relief of noninfectious diarrhea in adult patients with HIV/AIDS on antiretroviral therapy. Results from the ADVENT trial showed that crofelemer reduced symptoms of secretory diarrhea in HIV/AIDS patients. Because crofelemer is not systemically absorbed, this agent is well tolerated by patients, and in clinical trials it has been associated with minimal adverse events. Crofelemer has a unique mechanism of action, which may offer a more reliable treatment option for HIV patients who experience chronic secretory diarrhea from antiretroviral therapy.

Protective effects of alanyl-glutamine supplementation against nelfinavir-induced epithelial impairment in IEC-6 cells and in mouse intestinal mucosa

PURPOSE

Human Immunodeficiency Virus (HIV) protease inhibitors (PI) remain a crucial component of highly active therapy (HAART) and recently have been demonstrated to have potent antitumor effect on a wide variety of tumor cell lines. However, discontinuation of therapy is an important issue, which may be related to various side-effects, especially diarrhea. The aim of this study was to evaluate the effects of nelfinavir (NFV), an HIV PI, and of alanyl-glutamine (AQ) supplementation, on intestinal cell migration, proliferation, apoptosis and necrosis, using IEC-6 cells and on intestinal crypt depth, villus length, villus area, mitotic index and apoptosis in Swiss mice.

METHODS

Migration was evaluated at 12 and 24 h after injury using a wound healing assay. Cellular proliferation was measured indirectly at 24 and 48 h using tetrazolium salt WST-1. Apoptosis and necrosis were measured by flow cytometry using the Annexin V assay. Intestinal morphometry and mitotic index in vivo were assessed following a seven-day treatment with 100 mg/kg of NFV, given orally. In vivo proliferation and apoptosis were evaluated by intestinal crypt mitotic index and immunohistochemistry, respectively.

RESULTS

In vitro, AQ supplementation enhanced IEC-6 cell migration and proliferation, following challenge with NFV. In vivo, AQ increased intestinal villus length, villus area, crypt depth and cell proliferation and cell migration, following treatment with NFV. AQ did not decrease cell death induced by NFV both in vivo and in vitro.

CONCLUSIONS

AQ supplementation is potentially beneficial in preventing the effects of PIs, such as NFV, in the intestinal tract.

Etiology and pharmacologic management of noninfectious diarrhea in HIV-infected individuals in the highly active antiretroviral therapy era

Diarrhea remains a common problem for patients with human immunodeficiency virus (HIV) infection despite highly active antiretroviral therapies (HAART) and can negatively affect patient quality of life and lead to discontinuation or switching of HAART regimens. In the era of HAART, diarrhea from opportunistic infections is uncommon, and HIV-associated diarrhea often has noninfectious causes, including HAART-related adverse events and HIV enteropathy. Diarrhea associated with HAART is typically caused by protease inhibitors (eg, ritonavir), which may damage the intestinal epithelial barrier (leaky-flux diarrhea) and/or alter chloride ion secretion (secretory diarrhea). HIV enteropathy may result from direct effects of HIV on gastrointestinal tract cells and on the gastrointestinal immune system and gut-associated lymphoid tissue, which may be active sites of HIV infection and ongoing inflammation and mucosal damage. New therapies targeting the pathogenic mechanisms of noninfectious diarrheas are needed.

HIV exposure does not worsen outcome in stage III necrotizing enterocolitis with current treatment protocols

BACKGROUND/PURPOSE

The heavy burden of maternal HIV infection in developing countries such as South Africa has resulted in a high prevalence of premature birth and necrotizing enterocolitis (NEC). Uninfected infants born to HIV-infected mothers also demonstrate immune deficiencies. It is, therefore, essential to have a better understanding of how to mitigate HIV as an independent risk factor for surgically treated NEC and to evaluate the relevant contributing factors in the presence of an aggressive strategy of pasteurized breast milk feeding and antiretroviral prophylaxis.

METHODS

Infants with stage IIIb NEC presenting over a 4-year period were retrospectively reviewed. HIV-exposed infants were compared with non-HIV-exposed infants. Contributing factors were evaluated and studied by systematic statistical methods to evaluate risk.

RESULTS

Twenty percent (17/87) infants were HIV-exposed, and 80% (70/87), unexposed, whereas a further 10 (total, n = 97) had unknown HIV exposure status. Demographics and other perinatal risk factors between the 2 groups were not significantly different other than that HIV-exposed infants received pasteurized breast milk and nonexposed infants received unpasteurized breast milk. There were no statistically significant differences between the groups with respect to disease presentation or severity, surgical findings or type of surgery, postoperative complications, survival, or timing of death. Trends toward higher antenatal steroid exposure and increased postoperative sepsis in the HIV-exposed group (P = .03) were noted but were not related. All HIV-exposed infants received antiretrovirals; there were no significant differences on subanalysis between different antiretroviral regimens.

CONCLUSIONS

HIV-exposed infants do not have a more severe disease course nor more adverse outcomes in stage IIIb NEC than unexposed infants. Significant factors were antenatal steroids and post-NEC infective episodes.