Establishment of a reverse genetics system for SARS-CoV-2 using circular polymerase extension reaction

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been identified as the causative agent of coronavirus disease 2019 (COVID-19). Although multiple mutations have been observed in SARS-CoV-2, functional analysis of each mutation of SARS-CoV-2 has been limited by the lack of convenient mutagenesis methods. In this study, we establish a PCR-based, bacterium-free method to generate SARS-CoV-2 infectious clones. Recombinant SARS-CoV-2 could be rescued at high titer with high accuracy after assembling 10 SARS-CoV-2 cDNA fragments by circular polymerase extension reaction (CPER) and transfection of the resulting circular genome into susceptible cells. The construction of infectious clones for reporter viruses and mutant viruses could be completed in two simple steps: introduction of reporter genes or mutations into the desirable DNA fragments (∼5,000 base pairs) by PCR and assembly of the DNA fragments by CPER. This reverse genetics system may potentially advance further understanding of SARS-CoV-2.

Ponesimod suppresses hepatitis B virus infection by inhibiting endosome maturation

The discovery of novel antivirals to treat hepatitis B virus (HBV) infection is urgently needed, as the currently available drugs mainly target viral proteins at replication step, whereas host factors also play significant roles in HBV infection. Although numerous studies have reported candidate drugs for HBV treatment, there remains a need to find a new drug that may target other steps of the HBV life cycle. In this study, by drug screening of a 533 G-protein-coupled receptors (GPCRs)-associated compound library, we identified ponesimod, a selective agonist of sphingosine-1-phosphate receptor 1 (S1P₁), as a drug candidate for the suppression of HBV infection. However, the anti-HBV effect of ponesimod is independent of S1P₁ and other sphingosine-1-phosphate receptors (S1PRs). Treatment with ponesimod at an early step of infection but not at a post-entry step significantly reduced the HBV relaxed circular DNA (rcDNA) level in a dose-dependent manner. Ponesimod treatment did not inhibit attachment, binding, or internalization of HBV particles via endocytosis through an interaction with sodium taurocholate cotransporting polypeptide (NTCP) or epidermal growth factor receptor (EGFR). Importantly, during the transportation of HBV particles to the nucleus, co-localization of HBV with early endosomes but not with late endosomes and lysosomes was induced by the treatment with ponesimod, suggesting that ponesimod interferes with the conversion of early endosomes to late endosomes without significant damage to cellular growth. Conclusion: Ponesimod is a promising anti-HBV drug targeting the endosome maturation of HBV. This finding can be applied to the development of novel antivirals that target the trafficking pathway of HBV particles.

Various miRNAs compensate the role of miR-122 on HCV replication

One of the determinants for tissue tropism of hepatitis C virus (HCV) is miR-122, a liver-specific microRNA. Recently, it has been reported that interaction of miR-122 to HCV RNA induces a conformational change of the 5'UTR internal ribosome entry site (IRES) structure to form stem-loop II structure (SLII) and hijack of translating 80S ribosome through the binding of SLIII to 40S subunit, which leads to efficient translation. On the other hand, low levels of HCV-RNA replication have also been detected in some non-hepatic cells; however, the details of extrahepatic replication remain unknown. These observations suggest the possibility that miRNAs other than miR-122 can support efficient replication of HCV-RNA in non-hepatic cells. Here, we identified a number of such miRNAs and show that they could be divided into two groups: those that bind HCV-RNA at two locations (miR-122 binding sites I and II), in a manner similar to miR-122 (miR-122-like), and those that target a single site that bridges sites I and II and masking both G28 and C29 in the 5'UTR (non-miR-122-like). Although the enhancing activity of these non-hepatic miRNAs were lower than those of miR-122, substantial expression was detected in various normal tissues. Furthermore, structural modeling indicated that both miR-122-like and non-miR-122-like miRNAs not only can facilitate the formation of an HCV IRES SLII but also can stabilize IRES 3D structure in order to facilitate binding of SLIII to the ribosome. Together, these results suggest that HCV facilitates miR-122-independent replication in non-hepatic cells through recruitment of miRNAs other than miR-122. And our findings can provide a more detailed mechanism of miR-122-dependent enhancement of HCV-RNA translation by focusing on IRES tertiary structure.

Rimonabant suppresses RNA transcription of hepatitis B virus by inhibiting hepatocyte nuclear factor 4α

Chronic infection with hepatitis B virus (HBV) sometime induces lethal cirrhosis and hepatocellular carcinoma. Although nucleot(s)ide analogs are used as main treatment for HBV infection, the emergence of the drug-resistant viruses has become a problem. To discover novel antivirals with low side effects and low risk of emergence of resistant viruses, screening for anti-HBV compounds was performed with compound libraries of inhibitors targeting G-protein-coupled receptors (GPCRs). HepG2-hNTCP C4 cells infected with HBV were treated with various GPCR inhibitors and harvested at 14 day postinfection for quantification of core protein in the first screening or relaxed circular DNA in the second screening. Finally, we identified a cannabinoid receptor 1 inhibitor, rimonabant, as a candidate showing anti-HBV effect. In HepG2-hNTCP C4 cells, treatment with rimonabant suppressed HBV propagation at the viral RNA transcription step but had no effect on entry or covalently closed circular DNA level. The values of half maximal inhibitory concentration, half maximal effective concentration, and selectivity index of rimonabant in primary human hepatocyte (PHH) are 2.77 μm, 40.4 μm, and 14.6, respectively. Transcriptome analysis of rimonabant-treated primary hepatocytes by RNA sequencing revealed that the transcriptional activity of hepatocyte nuclear factor 4α (HNF4α), which is known to stimulate viral RNA synthesis, was depressed. By treatment of PHH with rimonabant, the expression level of HNF4α protein and the production of the messenger RNAs (mRNAs) of downstream factors promoted by HNF4α were reduced while the amount of HNF4α mRNA was not altered. These results suggest that treatment with rimonabant suppresses HBV propagation through the inhibition of HNF4α activity.

Characterization of human pegivirus infection in liver transplantation recipients

Approximately 2% of healthy persons are infected with human pegivirus (HPgV). HPgV is transmitted via vertical, sexual, and blood-borne routes. Recently, the association of HPgV infection with the risk of lymphoma was reported. Here, we examined the prevalence of chronic HPgV infection in liver transplantation (LT) recipients and patients with hepatectomy and the influence of HPgV infection after LT on clinical and perioperative factors. We enrolled 313 LT recipients and 187 patients with hepatectomy who received care at the Kyusyu University Hospital between May 1997 and September 2017. Of the 313 recipients and 187 patients enrolled in this study, 44 recipients (14.1%) and 2 patients (1.1%) had HPgV viremia, respectively. There was no significant association between HPgV infection and LT outcomes. Interestingly, one recipient was infected with HPgV during the peritransplant period, which was likely transmitted via blood transfusion because HPgV RNA was detected from the blood bag transfused to the recipient during LT. We reviewed the available literature on the prevalence HPgV infections in other organ-transplanted patients and whether they impacted clinical outcomes. They also had the higher prevalence of HPgV infection, while it appears to be of low or no consequences. In addition, HPgV infection induced the upregulation of interferon-stimulated gene (ISG) expression in peripheral blood mononuclear cells. LT recipients had higher HPgV viremia compared to patients with hepatectomy. Although HPgV infection was not associated with LT-related outcomes, it induced ISG expression in recipients.

A novel occludin-targeting monoclonal antibody prevents hepatitis C virus infection in vitro

Since hepatitis C virus (HCV) is thought to enter into host hepatocytes using the same cellular pathways regardless of the genotypes, the host factors are promising targets to prevent and treat HCV infection. Human occludin (hOCLN) is one representative entry factor, and its second extracellular loop (EC2) contributes to the species selectivity of HCV-susceptibility. However, the exact function of hOCLN during HCV entry remains unknown, and no hOCLN-targeting antibodies or synthetic drugs that prevent and treat HCV infection have yet been developed. Here we generated the anti-hOCLN-EC2 monoclonal antibody (mAb) 67-2, and demonstrated that it efficiently inhibited HCV infection in the HCV-permissive human cell line Huh7.5.1. We also showed, using three different culture systems of Huh7.5.1 cells, that this novel mAb is accessible to OCLN from the basolateral side of hepatocytes but not from the apical side. In addition, our Western blot analyses indicated that the established 67-2 mAb reacted not only with hOCLN but also with mouse OCLN, strongly suggesting that 67-2 does not recognize the human-specific amino acids in OCLN-EC2. Moreover, we revealed that the anti-hOCLN-EC2 mAb 67-2 showed no adverse effects on cell viability or the barrier function of tight junctions.

Evaluation of viral contamination in a baculovirus expression system

Insect expression systems based on baculovirus are widely used for generating recombinant proteins. Here, the infectivity of baculoviruses under the physiological stresses of 'freeze-thaw' and sonication and the baculoviral contamination of recombinant proteins after protein purification were evaluated. Our findings suggest that Nonidet P-40 (NP-40) treatment of baculoviruses completely abolishes their infectivity and that recombinant proteins purified with affinity beads do not include infectious baculoviruses. We therefore suggest that baculovirus is completely inactivated by NP-40 treatment and that recombinant proteins are unlikely to be contaminated with infectious baculoviruses after their affinity purification.

Suppression of HBV replication by the expression of nickase- and nuclease dead-Cas9

Complete removal of hepatitis B virus (HBV) DNA from nuclei is difficult by the current therapies. Recent reports have shown that a novel genome-editing tool using Cas9 with a single-guide RNA (sgRNA) system can cleave the HBV genome in vitro and in vivo. However, induction of a double-strand break (DSB) on the targeted genome by Cas9 risks undesirable off-target cleavage on the host genome. Nickase-Cas9 cleaves a single strand of DNA, and thereby two sgRNAs are required for inducing DSBs. To avoid Cas9-induced off-target mutagenesis, we examined the effects of the expressions of nickase-Cas9 and nuclease dead Cas9 (d-Cas9) with sgRNAs on HBV replication. The expression of nickase-Cas9 with a pair of sgRNAs cleaved the target HBV genome and suppressed the viral-protein expression and HBV replication in vitro. Moreover, nickase-Cas9 with the sgRNA pair cleaved the targeted HBV genome in mouse liver. Interestingly, d-Cas9 expression with the sgRNAs also suppressed HBV replication in vitro without cleaving the HBV genome. These results suggest the possible use of nickase-Cas9 and d-Cas9 with a pair of sgRNAs for eliminating HBV DNA from the livers of chronic hepatitis B patients with low risk of undesirable off-target mutation on the host genome.

Host-derived apolipoproteins play comparable roles with viral secretory proteins Erns and NS1 in the infectious particle formation of Flaviviridae

Amphipathic α-helices of exchangeable apolipoproteins have shown to play crucial roles in the formation of infectious hepatitis C virus (HCV) particles through the interaction with viral particles. Among the Flaviviridae members, pestivirus and flavivirus possess a viral structural protein E^rns or a non-structural protein 1 (NS1) as secretory glycoproteins, respectively, while Hepacivirus including HCV has no secretory glycoprotein. In case of pestivirus replication, the C-terminal long amphipathic α-helices of E^rns are important for anchoring to viral membrane. Here we show that host-derived apolipoproteins play functional roles similar to those of virally encoded E^rns and NS1 in the formation of infectious particles. We examined whether E^rns and NS1 could compensate for the role of apolipoproteins in particle formation of HCV in apolipoprotein B (ApoB) and ApoE double-knockout Huh7 (BE-KO), and non-hepatic 293T cells. We found that exogenous expression of either E^rns or NS1 rescued infectious particle formation of HCV in the BE-KO and 293T cells. In addition, expression of apolipoproteins or NS1 partially rescued the production of infectious pestivirus particles in cells upon electroporation with an E^rns-deleted non-infectious RNA. As with exchangeable apolipoproteins, the C-terminal amphipathic α-helices of E^rns play the functional roles in the formation of infectious HCV or pestivirus particles. These results strongly suggest that the host- and virus-derived secretory glycoproteins have overlapping roles in the viral life cycle of Flaviviridae, especially in the maturation of infectious particles, while E^rns and NS1 also participate in replication complex formation and viral entry, respectively. Considering the abundant hepatic expression and liver-specific propagation of these apolipoproteins, HCV might have evolved to utilize them in the formation of infectious particles through deletion of a secretory viral glycoprotein gene.

The family Flaviviridae consists of 4 genera, namely Flavivirus, Pestivirus, Pegivirus, and Hepacivirus. Flaviviruses and pestiviruses can infect various species and tissues; however, infection of pegivirus and hepacivirus is observed in a strikingly restricted range of tissue and hosts. Although all the Flaviviridae viruses possess a similar genome structure, hepatitis C virus (HCV) from Hepacivirus encodes no secretory glycoprotein, such as E^rns of pestivirus and NS1 of flavivirus. The apolipoproteins, one of the host secretory glycoproteins, play important roles in the formation of infectious HCV particles through the interaction with viral particles. The data presented here show that the host-derived apolipoproteins and viral-derived E^rns and NS1 have overlapping roles in the maturation of infectious particles of Flaviviridae. Considering an abundant expression of apolipoproteins in the liver and their liver-specific propagation, HCV might have evolved to utilize the apolipoproteins in the formation of infectious particles through deletion of a gene encoding a secretory viral glycoprotein. The data of this manuscript also suggest that utilization of host factors in the viral life cycle is closely associated with the tissue- and species-specificities and evolution among Flaviviridae viruses.

Characterization of miR-122-independent propagation of HCV

miR-122, a liver-specific microRNA, is one of the determinants for liver tropism of hepatitis C virus (HCV) infection. Although miR-122 is required for efficient propagation of HCV, we have previously shown that HCV replicates at a low rate in miR-122-deficient cells, suggesting that HCV-RNA is capable of propagating in an miR-122-independent manner. We herein investigated the roles of miR-122 in both the replication of HCV-RNA and the production of infectious particles by using miR-122-knockout Huh7 (Huh7-122KO) cells. A slight increase of intracellular HCV-RNA levels and infectious titers in the culture supernatants was observed in Huh7-122KO cells upon infection with HCV. Moreover, after serial passages of HCV in miR-122-knockout Huh7.5.1 cells, we obtained an adaptive mutant, HCV_122KO, possessing G28A substitution in the 5’UTR of the HCV genotype 2a JFH1 genome, and this mutant may help to enhance replication complex formation, a possibility supported by polysome analysis. We also found the introduction of adaptive mutation around miR-122 binding site in the genotype 1b/2a chimeric virus, which originally had an adenine at the nucleotide position 29. HCV_122KO exhibited efficient RNA replication in miR-122-knockout cells and non-hepatic cells without exogenous expression of miR-122. Competition assay revealed that the G28A mutant was dominant in the absence of miR-122, but its effects were equivalent to those of the wild type in the presence of miR-122, suggesting that the G28A mutation does not confer an advantage for propagation in miR-122-rich hepatocytes. These observations may explain the clinical finding that the positive rate of G28A mutation was higher in miR-122-deficient PBMCs than in the patient serum, which mainly included the hepatocyte-derived virus from HCV-genotype-2a patients. These results suggest that the emergence of HCV mutants that can propagate in non-hepatic cells in an miR-122-independent manner may participate in the induction of extrahepatic manifestations in chronic hepatitis C patients.

A liver-specific microRNA, miR-122, is one of the key determinants of hepatitis C virus (HCV) hepatotropism and is required for efficient propagation of HCV. On the other hand, chronic infection with HCV is often associated with extrahepatic manifestations (EHMs), and a low level of HCV-RNA replication has been detected in some non-hepatic cells. Nonetheless, the detailed mechanisms underlying these phenomena remain unknown. Here, we show that miR-122 is dispensable for low-level replication or infectious particle formation, and a mutant virus adapted to miR-122-knockout cells exhibited efficient but miR-122-independent propagation. The adaptive virus of HCV genotype 2a possessed a G28A substitution in the 5’UTR and facilitated efficient replication complex formation under an miR-122-deficient condition, while it propagated at a level comparable to the wild type HCV in the presence of miR-122. Moreover, various adaptive mutations including C30U were introduced into genotype 1b, which originally had an adenine at the nucleotide position 29. These observations suggest that substitutions that yield miR-122-independent propagation are not induced during propagation in hepatocytes; however, treatment with an miR-122 inhibitor or persistent infection of HCV in non-hepatic cells may induce the emergence of mutant viruses, as evidenced by clinical samples.

Quasispecies of Hepatitis C Virus Participate in Cell-Specific Infectivity

It is well documented that a variety of viral quasispecies are found in the patients with chronic infection of hepatitis C virus (HCV). However, the significance of quasispecies in the specific infectivity to individual cell types remains unknown. In the present study, we analyzed the role of quasispecies of the genotype 2a clone, JFH1 (HCVcc), in specific infectivity to the hepatic cell lines, Huh7.5.1 and Hep3B. HCV RNA was electroporated into Huh7.5.1 cells and Hep3B/miR-122 cells expressing miR-122 at a high level. Then, we adapted the viruses to Huh7 and Hep3B/miR-122 cells by serial passages and termed the resulting viruses HCVcc/Huh7 and HCVcc/Hep3B, respectively. Interestingly, a higher viral load was obtained in the homologous combination of HCVcc/Huh7 in Huh7.5.1 cells or HCVcc/Hep3B in Hep3B/miR-122 cells compared with the heterologous combination. By using a reverse genetics system and deep sequence analysis, we identified several adaptive mutations involved in the high affinity for each cell line, suggesting that quasispecies of HCV participate in cell-specific infectivity.

Lipoprotein Receptors Redundantly Participate in Entry of Hepatitis C Virus

Scavenger receptor class B type 1 (SR-B1) and low-density lipoprotein receptor (LDLR) are known to be involved in entry of hepatitis C virus (HCV), but their precise roles and their interplay are not fully understood. In this study, deficiency of both SR-B1 and LDLR in Huh7 cells was shown to impair the entry of HCV more strongly than deficiency of either SR-B1 or LDLR alone. In addition, exogenous expression of not only SR-B1 and LDLR but also very low-density lipoprotein receptor (VLDLR) rescued HCV entry in the SR-B1 and LDLR double-knockout cells, suggesting that VLDLR has similar roles in HCV entry. VLDLR is a lipoprotein receptor, but the level of its hepatic expression was lower than those of SR-B1 and LDLR. Moreover, expression of mutant lipoprotein receptors incapable of binding to or uptake of lipid resulted in no or slight enhancement of HCV entry in the double-knockout cells, suggesting that binding and/or uptake activities of lipid by lipoprotein receptors are essential for HCV entry. In addition, rescue of infectivity in the double-knockout cells by the expression of the lipoprotein receptors was not observed following infection with pseudotype particles bearing HCV envelope proteins produced in non-hepatic cells, suggesting that lipoproteins associated with HCV particles participate in the entry through their interaction with lipoprotein receptors. Buoyant density gradient analysis revealed that HCV utilizes these lipoprotein receptors in a manner dependent on the lipoproteins associated with HCV particles. Collectively, these results suggest that lipoprotein receptors redundantly participate in the entry of HCV.

Hepatitis C virus (HCV) utilizes several receptors to enter hepatocytes, including scavenger receptor class B type 1 (SR-B1) receptor and low-density lipoprotein receptor (LDLR). HCV particles interact with lipoprotein and apolipoproteins to form complexes termed lipoviroparticles. Several reports have shown that SR-B1 and LDLR participate in the entry of lipoviroparticles through interaction with lipoproteins. However, the precise roles of SR-B1 and LDLR in HCV entry have not been fully clarified. In this study, we showed that SR-B1 and LDLR have a redundant role in HCV entry. In addition, we showed that very low-density lipoprotein receptor (VLDLR) played a role in HCV entry similar to the roles of SR-B1 and LDLR. Interestingly, VLDLR expression was low in the liver in contrast to the abundant expressions of SR-B1 and LDLR, but high in several extrahepatic tissues. Our data suggest that lipoprotein receptors participate in the entry of HCV particles associated with various lipoproteins.

Roles of Lipoproteins and Apolipoproteins in Particle Formation of Hepatitis C Virus

More than 160 million people worldwide are infected with hepatitis C virus (HCV), and cirrhosis and hepatocellular carcinoma induced by HCV infection are life-threatening diseases. HCV takes advantage of many aspects of lipid metabolism for an efficient propagation in hepatocytes. Due to the morphological and physiological similarities of HCV particles to lipoproteins, lipid-associated HCV particles are named lipoviroparticles. Recent analyses have revealed that exchangeable apolipoproteins directly interact with the viral membrane to generate infectious HCV particles. In this review, we summarize the roles of lipid metabolism in the life cycle of HCV.

Analysis of the Bombyx mori nucleopolyhedrovirus ie-1 promoter in insect, mammalian, plant, and bacterial cells

The Bombyx mori nucleopolyhedrovirus (BmNPV) ie-1 promoter exhibits strong transcriptional activity and is used in transient foreign gene expression systems in insect cells. In a reporter assay experiment using the BmNPV ie-1 promoter, we found that it exhibited activity even in non-host mammalian BHK cells, plant BY-2 cells, and also bacterial Escherichia coli cells. An analysis using a deletion series of the BmNPV ie-1 promoter demonstrated that the core promoter region of this promoter was sufficient to display promoter activity in BHK cells, BY-2 cells, and E. coli cells, whereas upstream elements were required for higher activity in insect cells. Furthermore, we found that the BmNPV ie-1 promoter exhibited sufficient activity for a β-galactosidase assay in E. coli cells. The results obtained here suggest that the BmNPV ie-1 promoter has potential as a universal promoter for transient expression systems in insect, mammalian, plant, and bacterial cells.

Tightly regulated expression of Autographa californica multicapsid nucleopolyhedrovirus immediate early genes emerges from their interactions and possible collective behaviors

To infect their hosts, DNA viruses must successfully initiate the expression of viral genes that control subsequent viral gene expression and manipulate the host environment. Viral genes that are immediately expressed upon infection play critical roles in the early infection process. In this study, we investigated the expression and regulation of five canonical regulatory immediate-early (IE) genes of Autographa californica multicapsid nucleopolyhedrovirus: ie0, ie1, ie2, me53, and pe38. A systematic transient gene-expression analysis revealed that these IE genes are generally transactivators, suggesting the existence of a highly interactive regulatory network. A genetic analysis using gene knockout viruses demonstrated that the expression of these IE genes was tolerant to the single deletions of activator IE genes in the early stage of infection. A network graph analysis on the regulatory relationships observed in the transient expression analysis suggested that the robustness of IE gene expression is due to the organization of the IE gene regulatory network and how each IE gene is activated. However, some regulatory relationships detected by the genetic analysis were contradictory to those observed in the transient expression analysis, especially for IE0-mediated regulation. Statistical modeling, combined with genetic analysis using knockout alleles for ie0 and ie1, showed that the repressor function of ie0 was due to the interaction between ie0 and ie1, not ie0 itself. Taken together, these systematic approaches provided insight into the topology and nature of the IE gene regulatory network.

High-Level Secretory Production of Phospholipase A1by Saccharomyces cerevisiae and Aspergillus oryzae

Phospholipase A1 (PLA1) is a hydrolytic enzyme that catalyzes the removal of the acyl group from position 1 of lecithin to form lysolecithin. The PLA1 gene, which had been cloned from Aspergillus oryzae, was expressed in Saccharomyces cerevisiae and A. oryzae. Through the modification of the medium composition and the feeding conditions of substrate, the production level of PLA1 by S. cerevisiae was increased to a level fivefold higher than that indicated in a previous report. In the case of A. oryzae, introduction of multicopies of PLA1 expression units, and the morphological change from the pellet form to the filamentous form were effective for the enhancement of PLA1 production. We succeeded in producing 3,500 U/ml of PLA1 using an industrial-scale fermentor.

Baculovirus: an insect-derived vector for diverse gene transfer applications

Insect-derived baculoviruses have emerged as versatile and safe workhorses of biotechnology. Baculovirus expression vectors (BEVs) have been applied widely for crop and forest protection, as well as safe tools for recombinant protein production in insect cells. However, BEVs ability to efficiently transduce noninsect cells is still relatively poorly recognized despite the fact that efficient baculovirus-mediated in vitro and ex vivo gene delivery into dormant and dividing vertebrate cells of diverse origin has been described convincingly by many authors. Preliminary proof of therapeutic potential has also been established in preclinical studies. This review summarizes the advantages and current status of baculovirus-mediated gene delivery. Stem cell transduction, preclinical animal studies, tissue engineering, vaccination, cancer gene therapy, viral vector production, and drug discovery are covered.

Ultrasonic evaluation of the radial artery diameter in a local population from Texas

BACKGROUND

Radial access is the preferred route for cardiac catheterization; however, small radial arterial diameters can make complex procedures difficult. The assessment of radial artery diameters prior to intervention may be beneficial for the interventional cardiologist. Our aim was to measure the diameter of radial arteries in a study sample from our population, and to analyze the feasibility of using larger sheaths for radial interventions.

METHODS

The right radial artery diameter of 100 volunteers was measured using an ultrasound technique. A logistic regression analysis was performed to identify factors associated with small arterial diameters.

RESULTS

The average age of our sample was 35 years, 40% were male, and the mean body mass index (BMI) was 27 kg/m². The mean right arterial diameter for our population was 2.22 ± 0.35 mm. No strong direct association was found between diameters with age, height, weight, and body surface area. Forty-two percent of the patients had diameters larger than 5 Fr sheaths, 20% of the subjects had a diameter larger than 6 Fr sheaths, and 5% of the patients had diameters larger than 7 Fr sheaths. Logistic regression analysis revealed that female volunteers were associated with smaller arterial diameters (odds ratio [OR], 4.0; confidence interval [CI], 1.51-10.51; P=.005), while increases in BMI were associated with larger arterial diameters (OR, 0.21; CI, 0.07-0.61; P=.004).

CONCLUSION

Six Fr sheaths can be used in a significant proportion of our population. Careful selection of male patients with a larger BMI may help the interventionist in advance for planning a radial procedure with larger sheaths.