Noncirrhotic portal hypertension in HIV infection. Curr Opin Infect Dis. 2011;24:12-18. [PMID: 21157331 DOI: 10.1097/qco.0b013e3283420f08]

[Portosinusoidal vascular disorder: A paradigm shift]

The term portosinusoidal vascular disorder (PSVD) refers to a clinical-pathological entity that encompasses those patients with intrahepatic vascular damage without cirrhosis at risk of developing severe complications of portal hypertension. Numerous systemic diseases, genetic disorders, and toxic agents have been associated with this pathology, making its diagnosis an important clinical challenge. The recent description of uniform diagnostic criteria and a better understanding of its pathophysiology will allow for better identification of patients, even in early stages of the disease. Although there is currently no effective etiological treatment available, early diagnosis allows for the development of preventive strategies for some severe complications of portal hypertension.

A Case of Non-cirrhotic Portal Hypertension With Antiphospholipid Syndrome

Nodular regenerative hyperplasia (NRH) and obliterative portal venopathy (OPV) are two causes of non-cirrhotic portal hypertension (NCPH), which is a vascular liver disease wherein clinical signs of portal hypertension (PHT), such as esophageal varices, ascites, and splenomegaly develop in the absence of cirrhosis and portal vein thrombosis. The etiology often remains unidentified, but herein we present the case of a 56-year-old male with NCPH and refractory ascites who underwent liver biopsy confirming NRH and OPV. Etiological workup revealed beta-2 glycoprotein-1 and anticardiolipin antibodies, concerning antiphospholipid syndrome (APS) despite no prior history of thrombosis. The patient underwent a transjugular intrahepatic portosystemic shunt (TIPS) procedure for his refractory ascites and was started on prophylactic anticoagulation owing to a concern for APS with clinical improvement in his ascites and shortness of breath. Pursuing TIPS earlier in the setting of refractory ascites, as well as offering anticoagulation therapy for patients with possible APS to prevent the development of potential thromboses, could be appropriate recommendations to prevent complications in the disease course. This case report highlights the need for further investigations on the etiologies, diagnosis pathways, and treatment options for NCPH.

Porto-sinusoidal vascular disorder

It is well established that portal hypertension can occur in the absence of cirrhosis, as reported in patients with immune disorders, infections and thrombophilia. However, similar histological abnormalities primarily affecting the hepatic sinusoidal and (peri)portal vasculature have also been observed in patients without portal hypertension. Thus, the term porto-sinusoidal vascular disorder (PSVD) has recently been introduced to describe a group of vascular diseases of the liver featuring lesions encompassing the portal venules and sinusoids, irrespective of the presence/absence of portal hypertension. Liver biopsy is fundamental for PSVD diagnosis. Specific histology findings include nodular regenerative hyperplasia, obliterative portal venopathy/portal vein stenosis and incomplete septal fibrosis/cirrhosis. Since other conditions including alcohol-related and non-alcoholic fatty liver disease, or viral hepatitis, or the presence of portal vein thrombosis may occur in patients with PSVD, their relative contribution to liver damage should be carefully assessed. In addition to histology and clinical diagnostic criteria, imaging and non-invasive tests such as liver and spleen stiffness measurements could aid in the diagnostic workup. The introduction of PSVD as a novel clinical entity will facilitate collaborative studies and investigations into the underlying molecular pathomechanisms encompassed by this term.

Trends in hospitalizations and deaths in HIV-infected patients in Spain over two decades

BACKGROUND

The prognosis of HIV infection dramatically improved after the introduction of triple antiretroviral therapy 25 years ago. Herein, we report the impact of further improvements in HIV management since then, looking at all hospitalizations in persons with HIV (PWH) in Spain.

METHODS

A retrospective study using the Spanish National Registry of Hospital Discharges. Information was retrieved since 1997-2018.

RESULTS

From 79 647 783 nationwide hospital admissions recorded during the study period, 532 668 (0.67%) included HIV as diagnosis. The mean age of PWH hospitalized increased from 33 to 51 years (P < 0.001). The rate of HIV hospitalizations significantly declined after 2008. Comparing hospitalizations during the first (1997-2007) and last (2008-2018) decades, the rate of non-AIDS illnesses increased, mostly due to liver disease (from 35.9 to 38.3%), cardiovascular diseases (from 12.4 to 28.2%), non-AIDS cancers (from 6.4 to 15.5%), and kidney insufficiency (from 5.4 to 13%). In-hospital deaths occurred in 5.5% of PWH, declining significantly over time. Although most deaths were the result from AIDS conditions (34.8%), the most frequent non-AIDS deaths were liver disease (47.1%), cardiovascular events (29.2%), non-AIDS cancers (24.2%), and kidney insufficiency (20.7%).

CONCLUSION

Hospital admissions in PWH significantly declined after 2008, following improvements in HIV management and antiretroviral therapy. Non-AIDS cancers, cardiovascular events and liver disease represent a growing proportion of hospital admissions and deaths in PWH.

Spleen stiffness measurements using point shear wave elastography detects noncirrhotic portal hypertension in human immunodeficiency virus

To assess the utility of spleen stiffness as a diagnostic tool in individuals with human immunodeficiency virus (HIV) and non-cirrhotic portal hypertension (NCPH).The Philips EPIQ7, a new point shearwave elastography (pSWE) technique, was used to assess liver and spleen stiffness in 3 patient groups. Group 1: HIV and NCPH (n = 11); Group 2: HIV with past didanosine (ddI) exposure without known liver disease or NCPH (n = 5); Group 3: HIV without known liver disease or ddI exposure (n = 9).Groups were matched for age, HIV chronicity, and antiretroviral treatment (including cumulative ddI exposure in Groups 1 and 2). Differences in liver and spleen stiffness (in kPa) between groups were analyzed using the Mann-Whiney U test.Liver and spleen stiffness were both significantly higher in NCPH versus ddI-exposed (P = .019 and P = .006) and ddI-unexposed controls (P = .038 and P < .001). Spleen stiffness was more effective than liver stiffness at predicting NCPH, area under receiver operating characteristic (AUROC) 0.812 versus 0.948. Combining the 2 variables improved the diagnostic performance, AUROC 0.961. The optimal cut-off for predicting NCPH using splenic stiffness was 25.4 kPa, with sensitivity 91%, specificity 93%, positive predictive value (PPV) 91%, negative predictive value (NPV) 93%, positive likelihood ratio 12.73, negative likelihood ratio 0.10. Spleen and liver stiffness scores were strongly correlated (P = .0004, 95% confidence interval [CI] 18, 59).Elevated spleen stiffness is observed in HIV with NCPH and can be quantified easily using pSWE with high diagnostic accuracy. Novel strategies such as pSWE for longitudinal monitoring of patients with HIV and NCPH should be considered.

Can we differentiate HIV-associated obliterative portopathy from liver cirrhosis using MRI?

AIM

To describe the magnetic resonance imaging (MRI) features of HIV-associated obliterative portopathy (HIV-OP) and determine the most indicative appearance of this condition on MRI by using a retrospective case-control study.

METHODS

MRI examinations of 24 patients with HIV-OP (16 men, 8 women; mean age = 48 ± 6.6 [SD] years; age range, 35-71 years) were analyzed by two blinded observers and compared with those obtained in 18 HIV-infected patients with hepatic cirrhosis (14 men, 4 women; mean age = 51 ± 3.4 [SD] years; age range, 35-60 years). Images were qualitatively and quantitatively analyzed with respect to imaging presentation. Comparisons were performed using uni- and multivariate analyses.

RESULTS

Regular liver contours had the highest accuracy for the diagnosis of HIV-OP (83%, 35 of 42; 95% confidence interval [CI], 69-93%) and was the most discriminating independent variable for the diagnosis of HIV-OP (odds ratio, 51; 95%CI, 4.96-1272%) (p < 0.0001). At multivariate analysis, the width of segment 4 in millimeters (OR = 1.23 [95%CI, 1.05-1.44%]; p = 0.011) and the presence of regular liver contours (OR = 7.69 [95%CI, 1.48-39.92%]; p = 0.015) were the variables independently associated with the diagnosis of HIV-OP.

CONCLUSIONS

Regular liver contours are the most discriminating independent variable for the diagnosis of HIV-OP but have limited accuracy. Familiarity with this finding may help differentiate HIV-OP from cirrhosis in HIV-infected patients.

KEY POINTS

• Regular liver contour is the most discriminating independent variable for the diagnosis of HIV-OP (odds ratio = 51) with 83% accuracy. • At multivariate analysis, the width of segment 4 in millimeters and the presence of regular liver contours are the variables independently associated with the diagnosis of HIV-OP. • MRI helps diagnose HIV-OP in the presence of several categorical findings, which are more frequently observed in HIV-OP patients than in HIV patients with cirrhosis.

Human Immunodeficiency Virus Infection, Antiretroviral Therapy, and Liver Pathology

The improvement in antiretroviral therapy has significantly impacted the lives of people living with human immunodeficiency virus (HIV). In high-income countries, HIV deaths are predominated by liver disease consequent to viral hepatitis coinfection, alcohol, and nonalcoholic fatty liver disease. Published liver pathology findings have shifted from being predominated by opportunistic infections to the metabolic effects of HIV and antiretroviral therapy as well as drug-induced liver injuries. Differences remain between high-income and low-income countries, where opportunistic infections and immune reconstitution syndromes, dominate findings.

Noncirrhotic Portal Hypertension in Perinatally HIV-infected Adolescents Treated With Didanosine-containing Antiretroviral Regimens in Childhood

BACKGROUND

Noncirrhotic portal hypertension (NCPH) has been reported in HIV-infected adults. Antiretroviral drugs, as well as genetic and thrombophilic predisposition, have been suggested as possible etiologic factors.

METHODS

Clinical data were collected from 6 HIV-infected patients attending the Infectious Diseases Departments at respectively Emma Children's Hospital Academic Medical Centre in Amsterdam, The Thai Red Cross AIDS Research Centre, Bangkok, Imperial College Healthcare NHS Trust, London who were diagnosed with NCPH. All underwent extensive blood analysis, liver ultrasound, liver elastography, esophagogastroduodenoscopy and percutaneous needle liver biopsy for histological evaluation.

RESULTS

We describe 6 perinatally HIV-infected adolescents, all female, who developed NCPH after prolonged exposure during childhood to a didanosine-containing antiretroviral regimen. Histology and electron microscopy showed periportal fibrosis and mitochondrial damage as key findings in their liver biopsies. One of these 6 patients required surgical intervention, the remainder have been managed conservatively to date.

CONCLUSIONS

Thus, symptomatic NCPH may present in adolescence after perinatally acquired HIV-1 infection. In this case series, risk factors included female sex and prolonged exposure to antiretroviral regimens that included the nucleoside-analogue didanosine in childhood.

Idiopathic noncirrhotic portal hypertension: current perspectives

The term idiopathic noncirrhotic portal hypertension (INCPH) has been recently proposed to replace terms, such as hepatoportal sclerosis, idiopathic portal hypertension, incomplete septal cirrhosis, and nodular regenerative hyperplasia, used to describe patients with a hepatic presinusoidal cause of portal hypertension of unknown etiology, characterized by features of portal hypertension (esophageal varices, nonmalignant ascites, porto-venous collaterals), splenomegaly, patent portal, and hepatic veins and no clinical and histological signs of cirrhosis. Physicians should learn to look for this condition in a number of clinical settings, including cryptogenic cirrhosis, a disease known to be associated with INCPH, drug administration, and even chronic alterations in liver function tests. Once INCPH is clinically suspected, liver histology becomes mandatory for the correct diagnosis. However, pathologists should be familiar with the histological features of INCPH, especially in cases in which histology is not only requested to exclude liver cirrhosis.

Recurrent recessive mutation in deoxyguanosine kinase causes idiopathic noncirrhotic portal hypertension

Despite advances in the diagnosis and management of idiopathic noncirrhotic portal hypertension, its pathogenesis remains elusive. Insight may be gained from study of early-onset familial idiopathic noncirrhotic portal hypertension, in which Mendelian mutations may account for disease. We performed exome sequencing of eight subjects from six kindreds with onset of portal hypertension of indeterminate etiology during infancy or childhood. Three subjects from two consanguineous families shared the identical rare homozygous p.N46S mutation in DGUOK, a deoxyguanosine kinase required for mitochondrial DNA replication; haplotype sharing demonstrated that the mutation in the two families was inherited from a remote common ancestor. All three affected subjects had stable portal hypertension with noncirrhotic liver disease for 6-16 years of follow-up. This mutation impairs adenosine triphosphate binding and reduces catalytic activity. Loss-of-function mutations in DGUOK have previously been implicated in cirrhosis and liver failure but not in isolated portal hypertension. Interestingly, treatment of patients with human immunodeficiency viral infection with the nucleoside analogue didanosine is known to cause portal hypertension in a subset of patients and lowers deoxyguanosine kinase levels in vitro; the current findings implicate these effects on deoxyguanosine kinase in the causal mechanism.

CONCLUSION

Our findings provide new insight into the mechanisms mediating inherited and acquired noncirrhotic portal hypertension, expand the phenotypic spectrum of DGUOK deficiency, and provide a new genetic test for a specific cause of idiopathic noncirrhotic portal hypertension. (Hepatology 2016;63:1977-1986).

Associations between lipodystrophy or antiretroviral medications and cirrhosis in patients with HIV infection or HIV/HCV coinfection

BACKGROUND

Many HIV antiretroviral medications have been associated with chronic liver injury. HIV-infected patients frequently develop HIV and highly active antiretroviral treatment-associated lipodystrophy syndrome (HALS), characterized by accumulation of intra-abdominal fat, insulin resistance, and hepatic steatosis. We sought to determine whether long-term exposure to specific antiretroviral medications or the presence of HALS predispose HIV-infected patients to the development of cirrhosis.

METHODS

HIV-infected patients with cirrhosis who received care in the Veterans Affairs Healthcare System nationally in 2009 were matched by hepatitis C virus (HCV) coinfection status and year of first visit for HIV to the Veterans Affairs Healthcare System with HIV-infected patients without cirrhosis in a 1 : 3 ratio.

RESULTS

Among HIV/HCV coinfected patients (593 with cirrhosis and 1591 matched controls), HALS was associated with a significantly increased risk for cirrhosis (adjusted odds ratio 1.6, 95% confidence interval 1.1-2.3), especially among Black patients (adjusted odds ratio 2.9, 95% confidence interval 1.6-5.2). In addition, among HIV/HCV coinfected patients, longer cumulative exposures to all antiretroviral medications, all nucleoside reverse transcriptase inhibitors, all protease inhibitors, and selected individual medications (didanosine, stavudine, and nelfinavir) were found to be significantly associated with cirrhosis. In contrast, among HIV-infected patients not coinfected with HCV (245 with cirrhosis and 658 matched controls), HALS or exposure to antiretroviral medications was found not to be significantly associated with cirrhosis, with the exception of didanosine.

CONCLUSION

HALS and cumulative exposure to nucleoside reverse transcriptase inhibitors and protease inhibitors, especially stavudine, didanosine, and nelfinavir, were found to be associated with the development of cirrhosis in HIV/HCV coinfected patients, but not in HIV-monoinfected patients.

HBV and HIV co-infection: Impact on liver pathobiology and therapeutic approaches

The consequences of hepatitis B virus (HBV) and human immunodeficiency virus (HIV) co-infection on progression of severe liver diseases is a serious public health issue, worldwide. In the co-infection cases, about 90% of HIV-infected population is seropositive for HBV where approximately 5%-40% individuals are chronically infected. In HIV co-infected individuals, liver-related mortality is estimated over 17 times higher than those with HBV mono-infection. The spectrum of HIV-induced liver diseases includes hepatitis, steatohepatitis, endothelialitis, necrosis, granulomatosis, cirrhosis and carcinoma. Moreover, HIV co-infection significantly alters the natural history of hepatitis B, and therefore complicates the disease management. Though several studies have demonstrated impact of HIV proteins on hepatocyte biology, only a few data is available on interactions between HBV and HIV proteins. Thus, the clinical spectrum as well as the complexity of the co-infection offers challenging fronts to study the underlying molecular mechanisms, and to design effective therapeutic strategies.

A case of non-cirrhotic portal hypertension associated with anti-retroviral therapy in a Japanese patient with human immunodeficiency virus infection

The diagnosis of non-cirrhotic portal hypertension (NCPH), a rare but potentially life-threatening complication in human immunodeficiency virus (HIV)-positive individuals, often occurs only after the emergence of fatal manifestations such as bleeding of esophageal varices. We herein report a female Japanese HIV patient who developed NCPH approximately 4 years after discontinuation of 65 months of didanosine (ddI) administration. The patient presented with severe ascites, bloody bowel discharge, extreme abdominal swelling, and symptoms of portal hypertension but no sign of liver cirrhosis. Examination revealed esophageal varices, oozing-like bleeding from a wide part of the colon, significant atrophy of the right lobe of the liver, and arterio-portal shunting and recanalization from the left medial segment branch of the portal vein to a paraumbilical vein, but no visible obstruction of the main trunk of the portal vein. Treatment for esophageal varices consisted of coagulation therapy with argon plasma after enforcement by endoscopic sclerotherapy and oral administration of β-blockers for elevated portal blood pressure. The patient has not experienced gastrointestinal bleeding in the approximately 5 years since the diagnosis of NCPH. Reviewing this case suggests the importance of suspecting NCPH in HIV patients with liver dysfunction of unknown etiology with a history of ddI and other purine analogs use, as well as the importance of controlling portal hypertension and esophageal varices in the treatment of NCPH.

Human immunodeficiency virus and nodular regenerative hyperplasia of liver: A systematic review

AIM: To investigate the diagnosis, pathogenesis, natural history, and management of nodular regenerative hyperplasia (NRH) in patients with human immunodeficiency virus (HIV).

METHODS: We performed a systematic review of the medical literature regarding NRH in patients with HIV. Inclusion criteria include reports with biopsy proven NRH. We studied the clinical features of NRH, in particular, related to its presenting manifestation and laboratory values. Combinations of the following keywords were implemented: “nodular regenerative hyperplasia”, “human immunodeficiency virus”, “noncirrhotic portal hypertension”, “idiopathic portal hypertension”, “cryptogenic liver disease”, “highly active antiretroviral therapy” and “didanosine”. The bibliographies of these studies were subsequently searched for any additional relevant publications.

RESULTS: The clinical presentation of patients with NRH varies from patients being completely asymptomatic to the development of portal hypertension – namely esophageal variceal bleeding and ascites. Liver associated enzymes are generally normal and synthetic function well preserved. There is a strong association between the occurrence of NRH and the use of antiviral therapies such as didanosine. The management of NRH revolves around treating the manifestations of portal hypertension. The prognosis of NRH is generally good since liver function is preserved. A high index of suspicion is required to make a identify NRH.

CONCLUSION: The appropriate management of HIV-infected persons with suspected NRH is yet to be outlined. However, NRH is a clinically subtle condition that is difficult to diagnose, and it is important to be able to manage it according to the best available evidence.

Antiretroviral and anti-hepatitis C virus direct-acting antiviral-related hepatotoxicity

Antiretroviral-related hepatotoxicity occurs commonly in patients with human immunodeficiency virus (HIV). Liver injury ranges from unconjugated hyperbilirubinemia and nodular regenerative hyperplasia to lactic acidosis and toxic hepatitis. Effective antiretroviral therapy has changed coinfected patients' primary morbidities and mortality to chronic liver disease rather than complications from HIV. Treatment for hepatitis C virus (HCV) is strongly encouraged early in all coinfected patients. However, drug-drug interactions must be considered to ensure safe and tolerable use alone or in combination with antiretroviral therapies. The first-generation and newer HCV direct-acting antivirals are promising in coinfected patients, with minimal side effects and hepatotoxicity.

Update on HIV/HCV coinfection

Liver disease is currently one of the leading causes of hospitalization and death in HIV-positive individuals. Coinfection with the hepatitis C virus (HCV) is a major contributor to this trend. Besides hepatic damage, which is enhanced in the presence of HIV-associated immunosuppression, HCV may contribute to disease in coinfected individuals by potentiating immune activation and chronic inflammation, which ultimately account for an increased risk of cardiovascular events, kidney disease, and cancers in this population. Fortunately, hepatitis C therapeutics has entered a revolutionary era in which we hope that most patients treated with the new oral direct-acting antivirals (DAA) will be cured. However, many challenges preclude envisioning a prompt elimination of HCV from the coinfected population. Issues that should be addressed include the following: (1) rising incidence of acute hepatitis C in men who have sex with men, and expansion/recrudescence of injection drug use in some settings/regions; (2) adverse drug interactions between antiretrovirals and DAA; and (3) high cost of DAA, which may lead many to defer or fail to access appropriate therapy.

Metabolomics discloses potential biomarkers for the noninvasive diagnosis of idiopathic portal hypertension

OBJECTIVES

Idiopathic portal hypertension (IPH) is a rare cause of portal hypertension that lacks a specific diagnostic test. Requiring ruling-out other causes of portal hypertension it is frequently misdiagnosed. This study evaluates whether using high-throughput techniques there is a metabolomic profile allowing a noninvasive diagnosis of IPH.

METHODS

Thirty-three IPH patients were included. Matched patients with cirrhosis (CH) and healthy volunteers (HV) were included as controls. Metabolomic analysis of plasma samples was performed using UPLC-time-of-flight-mass spectrometry. We computed Student's P-values, corrected by multiple comparison and VIP score (Variable Importance in the Projection). The metabolites were selected with an adjusted Benjamini Hochberg P value <0.05. We use markers with a greater VIP score, to build partial least squares projection to latent structures regression with discriminant analysis (PLS-DA) representative models to discriminate IPH from CH and from HV. The performance of the PLS-DA model was evaluated using R(2) and Q(2) parameter. An additional internal cross-validation was done.

RESULTS

PLS-DA analysis showed a clear separation of IPH from CH with a model involving 28 metabolites (Q(2)=0.67, area under the curve (AUC)=0.99) and a clear separation of IPH from healthy subjects with a model including 31 metabolites (Q(2)=0.75, AUC=0.98). After cross-validation, both models showed high rates of sensitivity (94.8 and 97.5), specificity (89.1 and 89.7), and AUC (0.98 and 0.98), reinforcing the strength of our findings.

CONCLUSIONS

A metabolomic profile clearly differentiating patients with IPH from CH and healthy subjects has been identified using subsets of 28 and 31 metabolites, respectively. Therefore, metabolomic analysis appears to be a valuable tool for the noninvasive diagnosis of IPH.

Genetic determinants of idiopathic noncirrhotic portal hypertension in HIV-infected patients

BACKGROUND

Noncirrhotic portal hypertension (NCPH) is a rare but potentially life-threatening complication in patients with human immunodeficiency virus (HIV). Cases of NCPH have been reported in HIV-negative individuals as result of treatment with thiopurines for leukemia or inflammatory bowel disease. Exposure to didanosine, which is also a purine analogue, predisposes to NCPH in the HIV setting. However, it is unclear why NCPH only develops in a small subset of didanosine-treated patients.

METHODS

A multicenter, case-control study was conducted to investigate the role of pharmacogenomics in NCPH in HIV patients with prior didanosine exposure. Three controls were chosen for each case, adjusted for sex, age, CD4 counts, plasma HIV-RNA, and site. Tagging 36 single-nucleotide polymorphisms (SNPs) at enzymes involved in the purine metabolism (inosine triphosphatase, 5'-nucleotidase cytosolic-II, purine nucleoside phosphorylase and xanthine oxidase) was performed using SNPlex microarray technology.

RESULTS

Eighty individuals were examined; 22 with NCPH and 58 matched controls. Two SNPs at the 5'-nucleotidase gene were associated with NCPH: rs11191561 (48% CG/GG vs 17% CC; P=.003) and rs11598702 (40% CC/CT vs 9% TT; P=.003). SNPs at another 2 loci at the xanthine oxidase gene were also associated with NCPH: rs1429376 (71% AA vs 23% CC/AC; P=.015) and rs1594160 (71% AA vs 23% CC/AC; P=.015). There was a cumulative risk of NCPH for these 4 SNPs: 7%, 26%, 42%, 50%, and 100%, respectively, for 0, 1, 2, 3, or all SNPs (P=.001).

CONCLUSIONS

SNPs at the 5'-nucleotidase and xanthine oxidase genes influence the risk of NCPH in HIV patients treated with didanosine.

Splenomegaly and variceal bleeding in a ten-year-old HIV-infected girl with noncirrhotic portal hypertension

Noncirrhotic portal hypertension is an uncommon liver disease of unknown origin, increasingly described in HIV-infected adults. Prolonged antiretroviral exposure, in particular to didanosine, and thrombophilic predisposition have been suggested as potential pathogenic factors. Data are limited in children. We describe a 10-year-old HIV-infected girl with noncirrhotic portal hypertension who presented with progressive spleen enlargement and variceal bleeding.

Microbial translocation in HIV infection: causes, consequences and treatment opportunities

Systemic immune activation is increased in HIV-infected individuals, even in the setting of virus suppression with antiretroviral therapy. Although numerous factors may contribute, microbial products have recently emerged as potential drivers of this immune activation. In this Review, we describe the intestinal damage that occurs in HIV infection, the evidence for translocation of microbial products into the systemic circulation and the pathways by which these products activate the immune system. We also discuss novel therapies that disrupt the translocation of microbial products and the downstream effects of microbial translocation.

Histopathologic evaluation of liver biopsy for cirrhosis

In current medical practice, the clinical diagnosis of cirrhosis is rendered when a patient has suggestive imaging findings or features of portal hypertension (pHTN). Liver biopsy may be considered to assess potential underlying cause(s). Cirrhosis, however, is not the only etiology of pHTN; in fact, schistosomiasis remains a significant factor worldwide. pHTN results from obstruction of hepatic blood flow; it is classified clinically based on either the anatomic location of obstruction or hepatic venous pressure gradient measurements. The clinical categories carry clinicopathologic significances. Histopathologically, pHTN is manifest with either cirrhotic or noncirrhotic features. Noncirrhotic pHTN results from a heterogeneous group of disease processes, all of which result in vascular remodeling with variable parenchymal nodularity and fibrosis. This review summarizes liver biopsy findings of cirrhosis and possible etiologies and provides a stepwise approach for the histologic differential diagnosis of a liver biopsy done for "cirrhosis."

Combination nucleoside/nucleotide reverse transcriptase inhibitors for treatment of HIV infection

INTRODUCTION

The combination of two nucleoside/nucleotide reverse transcriptase inhibitors (N(t)RTIs) and a third agent from another antiretroviral class is currently recommended for initial antiretroviral therapy. In general, N(t)RTIs remain relevant in subsequent regimens. There are currently six nucleoside reverse transcriptase inhibitors and one nucleotide reverse transcriptase inhibitor drug entities available, and several formulations that include two or more N(t)RTIs in a fixed-dose combination. These entities have heterogeneous pharmacological and clinical properties. Accordingly, toxicity, pill burden, dosing frequency, potential drug-drug interaction, preexisting antiretroviral drug resistance and comorbid conditions should be considered when constructing a regimen. This approach is critical in order to optimize virologic efficacy and clinical outcomes.

AREAS COVERED

This article reviews N(t)RTI combinations used in the treatment of HIV-infected adults. The pharmacological properties of each N(t)RTI, and the clinical trials that have influenced treatment guidelines are discussed.

EXPERT OPINION

It is likely that N(t)RTIs will continue to dominate the global landscape of HIV treatment and prevention, despite emerging interest in N(t)RTI-free combination therapy. Clinical domains where only few alternatives to N(t)RTIs exist include treatment of HIV/HBV coinfection and HIV-2. There is a need for novel N(t)RTIs with enhanced safety and resistance profiles compared with current N(t)RTIs.