Evaluation of hepatitis C virus as a risk factor for HIV-associated neuroretinal disorder.

BACKGROUND: Both hepatitis C virus (HCV) and human immunodeficiency virus (HIV) penetrate the central nervous system. HIV-associated neuroretinal disorder (HIV-NRD), a visual impairment of reduced contrast sensitivity and reading ability, is associated with cytokine dysregulation and genetic polymorphisms in the anti-inflammatory interleukin 10 (IL-10) signaling pathway. We investigated associations between HCV and HIV-NRD and between HCV and single-nucleotide polymorphisms (SNPs) in the IL-10 receptor 1 (IL10R1) gene. METHODS: Logistic and Cox regression analysis were used to analyze risk factors for HIV-NRD in 1576 HIV-positive patients who did not have an ocular opportunistic infection at enrollment. Median follow-up was 4.9 years (interquartile range, 2.4-8.8 years). Four IL10R1 SNPs were examined in a subset of 902 patients. RESULTS: The group included 290 patients with chronic HCV infection, 74 with prior infection, and 1212 with no HCV markers. There were 244 prevalent cases of HIV-NRD and 263 incident cases (rate = 3.9/100 person-years). In models adjusted for demographics, HIV treatment and status, liver function, and immune status, both the prevalence and incidence of HIV-NRD were significantly higher in patients with chronic HCV infection (odds ratio = 1.54; 95% confidence interval [CI], 1.03-2.31 and hazard ratio = 1.62; 95% CI, 1.13-2.34, respectively), compared to patients with no HCV markers. Chronic HCV was associated with rs2228055 and 2 additional IL-10R1 SNPs expected to reduce IL-10 signaling. HIV-NRD was not significantly associated with these SNPs. CONCLUSIONS: HCV is a possible risk factor for HIV-NRD. Genetic analysis suggests that alterations in the IL-10 signaling pathway may increase susceptibility to HIV-NRD and HCV infection. Inflammation may link HCV and HIV-NRD.

Methemoglobinemia in the Era of COVID-19: A Potential Confounder of Glycemic Control.

Glycated hemoglobin A1c (HbA1c) is frequently used as a measure of glycemic control but can be inaccurate in certain clinical scenarios leading to poor estimates of insulin requirements. We present the case of a 76-year-old man with diabetes and COVID infection. HbA1c was measured at 5.7%, though the patient reported home glucose readings of 200 to 300 mg/dL (11.1-16.65 mmol/L). Pulse oximetry on presentation was 50% to 60%, which initially improved to 93% with supplemental oxygen of 15 L via nonrebreather face mask. Treatment with remdesivir and dexamethasone was initiated, but the patient was again found to have low oxygen saturations requiring bilevel positive airway pressure and transfer to the intensive care unit. The patient was started on 1.1 U/kg of insulin daily in a basal-bolus regimen. The patient developed severe hyperglycemia requiring 2.4 U/kg to achieve glycemic control. Co-oximeter analysis of an arterial blood gas sample revealed methemoglobinemia. Exchange transfusion was performed with clinical improvement. Subsequent measurement of fructosamine was 360 umol/L (360 000 µmol/L), correlating with reported home glucose measurements. Methemoglobinemia may impair glycation of hemoglobin or interfere with measurement of HbA1c, thereby compromising the use of this molecule as a marker for glycemic control in patients with this condition.

Internal initiation stimulates production of p8 minicore, a member of a newly discovered family of hepatitis C virus core protein isoforms.

The hepatitis C virus (HCV) core gene is more conserved at the nucleic acid level than is necessary to preserve the sequence of the core protein, suggesting that it contains information for additional functions. We used a battery of anticore antibodies to test the hypothesis that the core gene directs the synthesis of core protein isoforms. Infectious viruses, replicons, and RNA transcripts expressed a p8 minicore containing the C-terminal portion of the p21 core protein and lacking the N-terminal portion. An interferon resistance mutation, U271A, which creates an AUG at codon 91, upregulated p8 expression in Con1 replicons, suggesting that p8 is produced by an internal initiation event and that 91-AUG is the preferred, but not the required, initiation codon. Synthesis of p8 was independent of p21, as shown by the abundant production of p8 from transcripts containing an UAG stop codon that blocked p21 production. Three infectious viruses, JFH-1 (2a core), J6/JFH (2a core), and H77/JFH (1a core), and a bicistronic construct, Bi-H77/JFH, all expressed both p8 and larger isoforms. The family of minicores ranges in size from 8 to 14 kDa. All lack the N-terminal portion of the p21 core. In conclusion, the core gene contains an internal signal that stimulates the initiation of protein synthesis at or near codon 91, leading to the production of p8. Infectious viruses of both genotype 1 and 2 HCV express a family of larger isoforms, in addition to p8. Minicores lack significant portions of the RNA binding domain of p21 core. Studies are under way to determine their functions.

Mutations in the hepatitis C virus core gene are associated with advanced liver disease and hepatocellular carcinoma.

PURPOSE: Hepatitis C virus (HCV) infection can promote the development of hepatocellular carcinoma (HCC). Published data implicate the HCV core gene in oncogenesis. We tested the hypothesis that core gene sequences from HCC patients differ from those of patients without cirrhosis/HCC. EXPERIMENTAL DESIGN: Full-length HCV sequences from HCC patients and controls were obtained from the investigators and GenBank and compared with each other. A logistic regression model was developed to predict the HCC risk of individual point mutations and other sequence features. Mutations in partial sequences (bases 36-288) from HCC patients and controls were also analyzed. The first base of the AUG start codon was designated position 1. RESULTS: A logistic regression model developed through analysis of full-length core gene sequences identified seven polymorphisms significantly associated with increased HCC risk (36G/C, 209A, 271U/C, 309A/C, 435A/C, 481A, and 546A/C) and an interaction term (for 209A-271U/C) that had an odds ratio <1.0. Three of these polymorphisms could be analyzed in the partial sequences. Two of them, 36G/C and 209A, were again associated with increased HCC risk, but 271U/C was not. The odds ratio of 209A-271U/C was not significant. CONCLUSIONS: HCV core genes from patients with and without HCC differ at several positions. Of interest, 209A has been associated with IFN resistance and HCC in previous studies. Our findings suggest that HCV core gene sequence data might provide useful information about HCC risk. Prospective investigation is needed to establish the temporal relationship between appearance of the viral mutations and development of HCC.

Glycosylated hemoglobin, but not advanced glycation end products, predicts severity of coronary artery disease in patients with or without diabetes.

BACKGROUND: The association between coronary artery disease (CAD) and diabetes mellitus (DM) is strong but the physiologic mechanisms responsible for this association remain unclear. Patients with DM exhibit high circulating levels of glycated proteins and lipoproteins called advanced glycation end products (AGEs) which have been implicated in the development of oxidative damage to vascular endothelium. We examined the relationships between the presence and extent of CAD and AGEs in patients undergoing elective coronary artery catheterization in an urban teaching hospital. METHODS: Patients with possible CAD (n = 364) were recruited prior to elective cardiac catheterization (52% male, 48% diabetic). Regression and correlation analyses were used to examine the relationship between serum AGE concentrations, soluble AGE receptor (sRAGE) concentration, HbA1c, LDL and the presence of obstructive CAD along with the burden of CAD measured by SYNTAX and SYNTAX II scores. RESULTS: AGE and sRAGE levels did not significantly correlate with any of the studied coronary artery disease parameters. HbA1c showed positive correlation with both SYNTAX and SYNTAX II scores in patients with and without diabetes. CONCLUSION: In this cross-sectional study of patients with possible CAD, serum AGEs and sRAGE concentrations did not correlate with SYNTAX or SYNTAX II scores regardless of diabetic status. HbA1C correlated positively with the SYNTAX and SYNTAX II scores in both diabetic and non-diabetic populations.

Clinicopathologic correlates of hepatitis C virus in brain: a pilot study.

Hepatitis C virus (HCV) has been detected in the brain tissues of 10 individuals reported to date; it is unclear what clinical factors are associated with this, and with what frequency it occurs. Accordingly, a pilot analysis utilizing reverse transcriptase-polymerase chain reaction (RT- PCR) to detect and sequence HCV in premortem plasma and postmortem brain and liver from 20 human immunodeficiency virus (HIV)-infected and 10 HIV-naive individuals was undertaken. RNA encoding the first 126 amino acids of the HCV E1 envelope protein and the majority of the E1 signal sequence was analyzed in parallel with an 80-base-long segment of the 5' untranslated region (UTR). Liver HCV was detected only in subjects with premortem HCV viremia (10 HIV-infected and 3 HIV-naive). Brain HCV was detected in 6/10 HCV/HIV-coinfected and 1/3 HCV-monoinfected subjects. In the setting of HIV, the magnitude of plasma HCV load did not correlate with the presence of brain HCV. However, coinfected patients with brain HCV were more often off antiretroviral therapy and tended to have higher plasma HIV loads than those with HCV restricted to liver. Furthermore, premortem cerebrospinal fluid (CSF) analysis revealed that HCV/HIV-coinfected patients with brain HCV had detectable CSF HIV, whereas those without brain HCV had undetectable CSF HIV loads (P = .0205). Neuropsychologic tests showed a trend for hierarchical impairment of abstraction/executive functioning in HIV/HCV coinfection, with mean T scores for HIV monoinfected patients 43.2 (7.3), for liver-only HCV 39.5 (9.0), and for those with HCV in brain and liver 33.2 (5.1) (P = .0927). Predominant brain HCV sequences did not match those of the plasma or liver in 4 of the 6 coinfected patients analyzed. We conclude that in the setting of HIV/HCV coinfection, brain HCV is a common phenomenon unrelated to the magnitude of HCV viremia, but related to active HIV disease and detectable CSF HIV. Furthermore, there is sequence evidence of brain compartmentalization. Differences in abstraction/executive function of HCV/HIV coinfected patients compared to HIV monoinfected warrant further studies to determine if neuropsychiatric effects are predicated upon brain infection.

Short communication: Inadequate vitamin D exacerbates parathyroid hormone elevations in tenofovir users.

Parathyroid hormone (PTH) elevations are associated with reduced bone mineral density and adverse health outcomes and have been reported in patients with HIV infection. We aimed to examine the impact of vitamin D status and tenofovir (TDF) use on PTH levels among HIV-infected patients receiving combination antiretroviral therapy (cART). Demographics, medication and supplement use, and clinical data, including 25-hydroxyvitamin D [25(OH)D] and PTH, were collected on 45 HIV-infected men on ART. Suboptimal vitamin D status was defined as 25(OH)D < 30 ng/ml. The relationship between antiretroviral agents, suboptimal 25(OH)D, and PTH levels was examined. Among subjects with suboptimal vitamin D status, PTH values greater than or equal to the ULN (87 pg/ml) were more common among TDF users than nonusers: 41% versus 0% (p = 0.018); and median PTH was higher in TDF users: 80 pg/ml versus 55 pg/ml (p = 0.02). Among TDF users, PTH was higher in the group with suboptimal 25(OH)D (p = 0.045). Multivariable linear regression showed that PTH was independently and directly related to TDF use (p = 0.017) and inversely related to 25(OH)D (p = 0.017). PTH was not related to the estimated glomerular filtration rate (p = 0.9). In this cross-sectional study of HIV-infected men on ART, the use of TDF and the level of 25(OH)D were independently associated with PTH levels. Because TDF is a potent and widely used antiretroviral drug, information about cofactors that may exacerbate its side effects is of significant clinical value.

The quasispecies nature and biological implications of the hepatitis C virus.

Many RNA viruses exist as a cloud of closely related sequence variants called a quasispecies, rather than as a population of identical clones. In this article, we explain the quasispecies nature of RNA viral genomes, and briefly review the principles of quasispecies dynamics and the differences with classical population genetics. We then discuss the current methods for quasispecies analysis and conclude with the biological implications of this phenomenon, focusing on the hepatitis C virus.

Molecular and bioinformatic evidence of hepatitis C virus evolution in brain.

BACKGROUND: Neurocognitive deficits in patients with hepatitis C virus (HCV) infection prompted a search for HCV in brain. RESULTS: HCV was present in the brains of 7 (54%) of 13 patients with viremia, as determined by 5' UTR and E1 (envelope 1) gene analysis. Brain HCV RNA consensus sequences differed from those in plasma and liver in 4 (57%) of 7 patients. The quality of HCV RNA from postmortem brain and liver was assessed and demonstrated to be suitable for sequence analysis. Quasispecies analysis revealed that several mutations present in clones from >1 brain region were absent in clones from liver and plasma. Brain-specific mutations defined several families of related sequences. The patterns of brain-specific mutations in these families were consistent with the evolution of HCV RNA from a common ancestor. Single-nucleotide-polymorphism analysis confirmed that a prominent brain-specific mutation constituted approximately 10% of HCV RNA in cerebellum and medulla but that this mutation was undetectable in the liver and plasma of the same patient. CONCLUSIONS: This study introduces novel methods for assessing RNA from postmortem samples. It increases the reported cases of HCV in the brain, provides the first E1 sequences from the brain, and contributes to the growing evidence that HCV replicates and evolves within the brain.