Three-Year Sustained Clinical Efficacy of Drug-Coated Balloon Angioplasty in a Real-World Femoropopliteal Cohort.

Purpose: To report the 36-month outcomes from the prospective, multicenter, single-arm IN.PACT Global Study (ClinicalTrials.gov identifier NCT01609296) evaluating the performance of the IN.PACT Admiral drug-coated balloon (DCB) in real-world patients with femoropopliteal occlusive disease. Materials and Methods: The IN.PACT Global Study was conducted at 64 international sites and enrolled 1535 patients with complex lesions, which included bilateral disease, multiple lesions, de novo in-stent restenosis, long lesions, and chronic total occlusions. The predefined full clinical cohort included 1406 patients (mean age 68.6 years; 67.8% men) with claudication or rest pain treated with the study DCB. Mean lesion length was 12.09±9.54 cm; 18.0% had in-stent restenosis, 35.5% were totally occluded, and 68.7% were calcified. Freedom from clinically-driven target lesion revascularization (CD-TLR) was evaluated through 36 months. The safety composite endpoint was freedom from device- and procedure-related death through 30 days and freedom from major target limb amputation and clinically-driven target vessel revascularization within 36 months. All safety and revascularization events were reviewed by an independent clinical events committee. Results: The Kaplan-Meier estimate of freedom from CD-TLR through 36 months was 76.9%. The composite safety endpoint was achieved in 75.6% of patients. The 36-month all-cause mortality rate was 11.6%, and the major target limb amputation rate was 1.0%. The Kaplan-Meier estimate of freedom from CD-TLR through 36 months was significantly lower in patients with chronic limb-threatening ischemia (CLTI) compared with claudicants (67.6% vs 78.0%; p=0.003). Lesions affecting both the superficial femoral artery (SFA) and popliteal artery had lower Kaplan-Meier freedom from CD-TLR through 36 months (69.2%) than either isolated SFA (79.7%) or popliteal artery lesions (76.5%; log- rank p<0.001). Predictors of CD-TLR through 36 months included increased lesion length, reference vessel diameter ≤4.5 mm, in-stent restenosis, bilateral disease, CLTI, and hyperlipidemia. Conclusion: DCB angioplasty with the IN.PACT Admiral DCB for femoropopliteal disease in a diverse and complex real-world population is associated with sustained clinical efficacy and low rates of reinterventions at 3 years after the initial procedure.

The IN.PACT DEEP Clinical Drug-Coated Balloon Trial: 5-Year Outcomes.

OBJECTIVES: The goal of this study was to evaluate the 5-year follow-up data of the IN.PACT DEEP (Randomized IN.PACT Amphirion Drug-Coated Balloon [DCB] vs. Standard Percutaneous Transluminal Angioplasty [PTA] for the Treatment of Below-the-Knee Critical Limb Ischemia [CLI]) trial. BACKGROUND: Initial studies from randomized controlled trials have shown comparable short-term outcomes of DCB angioplasty versus PTA in patients with CLI with infrapopliteal disease. However, the long-term safety and effectiveness of DCB angioplasty remain unknown in this patient population. METHODS: IN.PACT DEEP was an independently adjudicated prospective, multicenter, randomized controlled trial that enrolled 358 subjects with CLI. Subjects were randomized 2:1 to DCB angioplasty or PTA. Assessments through 5 years included freedom from clinically driven target lesion revascularization, amputation, and all-cause death. Additional assessments were conducted to identify risk factors for death and major amputation, including paclitaxel dose tercile. RESULTS: Freedom from clinically driven target lesion revascularization through 5 years was 70.9% and 76.0% (log-rank p = 0.406), and the incidence of the safety composite endpoint was 59.8% and 57.5% (log-rank p = 0.309) in the DCB angioplasty and PTA groups, respectively. The rate of major amputation was 15.4% for DCB angioplasty compared with 10.6% for PTA (log-rank p = 0.108). Given the recent concern regarding a late mortality signal in patients treated with paclitaxel-coated devices, additional analyses from this study showed no increase in all-cause mortality with DCB angioplasty (39.4%) compared with PTA (44.9%) (log-rank p = 0.727). Predictors of mortality included age, Rutherford category >4, and previous revascularization but not paclitaxel by dose tercile. CONCLUSIONS: Tibial artery revascularization in patients with CLI using DCB angioplasty resulted in comparable long-term safety and effectiveness as PTA. Paclitaxel exposure was not related to increased risk for amputation or all-cause mortality at 5-year follow-up. (Study of IN.PACT Amphirion™ Drug Eluting Balloon vs. Standard PTA for the Treatment of Below the Knee Critical Limb Ischemia [INPACT-DEEP]; NCT00941733).

Female sex is associated with comparable 5-year outcomes after contemporary endovascular aneurysm repair despite more challenging anatomy.

BACKGROUND: Women with abdominal aortic aneurysms less often meet anatomic criteria for endovascular repair and experience worse perioperative and long-term survival. METHODS: We compared long-term survival, aneurysm-related mortality, and rates of endoleaks and reinterventions between male and female patients in the Endurant Stent Graft Natural Selection Global Postmarket Registry (ENGAGE) using 2:1 propensity score matching. RESULTS: There were 1130 male patients and 133 female patients, yielding 399 patients after matching (266 male patients, 133 female patients). Female patients were older, with smaller aneurysms, smaller iliac arteries, and shorter, more angulated necks, and they were more often treated outside the device instructions for use (all P < .001). Through 5 years, female patients experienced overall mortality comparable to that of well-matched male patients (34% vs 38%, respectively; hazard ratio, 0.89 [0.61-1.29]; P = .54) and lower aneurysm-related mortality (0% vs 3%; P = .047). Female patients experienced higher rates of any postoperative type IA endoleak through 5 years (10% vs 1%; P < .001) but comparable rates of secondary endovascular procedures (14% vs 16%; P = .40). Female sex was independently associated with significantly higher risk of long-term type IA endoleaks (hazard ratio, 4.8 [1.2-20.8]; P = .04), even after accounting for anatomic factors. No female patient experienced aneurysm rupture during follow-up, and only one female patient underwent conversion to open repair. CONCLUSIONS: Despite more challenging anatomy, female patients in the ENGAGE registry had long-term outcomes comparable to those of male patients. However, female patients experienced higher rates of type IA endoleaks. Although standard endovascular aneurysm repair remains a viable solution for most women, whether high-risk patients may be better served with open surgery, custom-made devices, EndoAnchors (Aptus Endosystems, Sunnyvale, Calif), or chimneys is worthy of further study.

Endograft treatment of ruptured abdominal aortic aneurysms using the Talent aortouniiliac system: an international multicenter study.

OBJECTIVE: To understand the potential of endovascular aneurysm repair (EVAR) in patients presenting with a ruptured abdominal aortic aneurysm (rAAA), the proportion in whom this procedure was applicable was assessed. Mortality and morbidity was also determined in patients treated with emergency EVAR (eEVAR) when anatomic and hemodynamic conditions allowed (ie, in the entire cohort with patients receiving endovascular and open repair combined). In addition, a comparison was made between the treatment group with eEVAR and open repair. METHODS: Between February 2003 and September 2004, 10 participating institutions enrolled a representative sample of 100 consecutive patients in whom eEVAR was considered. Patients in the New Endograft treatment in Ruptured abdominal aortic Aneurysm (ERA) trial were offered eEVAR or open repair in accordance with their clinical condition or anatomic configuration. Written informed consent was obtained from all patients or their legal representatives. The study included patients who were treated by stent-graft technique or by open surgery in the case of adverse anatomy for endoluminal stent-grafting or severe hemodynamic instability, or both. Data were collated in a centralized database for analysis. The study was sponsored and supported by Medtronic, and eEVAR was uniquely performed with a Talent aortouniiliac (AUI) system in all patients. Crude and adjusted 30-day or in-hospital and 3-month mortality rates were assessed for the entire group as a whole and the EVAR and open repair category separately. Complication rates were also assessed. RESULTS: Stent-graft repair was performed in 49 patients and open surgery in 51. No significant differences were observed between these treatment groups with regard to comorbidity at presentation, hemodynamic instability, and the proportion of patients who could be assessed by preoperative computed tomography scanning. Patients with eEVAR more frequently demonstrated a suitable infrarenal neck for endovascular repair, a longer infrarenal neck, and suitable iliac arteries for access than patients with open repair. The primary reason to perform open aneurysm repair was an unfavorable configuration of the neck in 80% of the patients. In patients undergoing eEVAR, operative blood loss was less, intensive care admission time was shorter, and the duration of mechanical ventilation was shorter (P < or = .02, all comparisons). The 30-day or in-hospital mortality was 35% in the eEVAR category, 39% in patients with open repair, and 37% overall. There was no statistically significant difference between the treatment groups with regard to crude mortality rates or rates adjusted for age, gender, hemodynamic shock, and pre-existent pulmonary disease. The cumulative 3-month all-cause mortality was 40% in the eEVAR group and 42% in the open repair group (no significant differences at crude and adjusted comparisons). The 3-month primary complication rate in the two treatment groups was similar at 59%. CONCLUSIONS: In approximately half the rAAA patients, eEVAR appeared viable. An unsuitable infrarenal neck was the most frequent cause to select open repair. In dedicated centers using a Talent AUI system, eEVAR appeared to be a feasible method for treatment of a rAAA. The overall first-month mortality did not differ across treatment groups (patients with endovascular and open repair combined), yet was somewhat lower than observed in a recent meta-analysis reporting on open repair.

Parasitology yesterday--following the trends.

The 1980s were a period of great activity in the field of parasitology that generated a vast amount of research published in approximately 20 specialist and several other learned journals. There was, however, no vehicle for disseminating the exciting discoveries that were being made in an immediate, easily readable and accessible form suitable for teachers, students and others interested in aspects of the subject that were broader than their own particular specialty. To fill this perceived gap, Elsevier decided in 1985 that it would be worthwhile publishing Parasitology Today to complement its other successful Trends journals. In this article, I review the breadth of coverage of topics published during the first year of Parasitology Today, most of which continue to be of interest today.

Human DNA polymerase iota promiscuous mismatch extension.

Human DNA polymerase iota is a low-fidelity template copier that preferentially catalyzes the incorporation of the wobble base G, rather than the Watson-Crick base A, opposite template T (Tissier, A., McDonald, J. P., Frank, E. G., and Woodgate, R. (2000) Genes Dev. 14, 1642-1650; Johnson, R. E., Washington, M. T., Haracska, L., Prakash, S., and Prakash, L. (2000) Nature 406, 1015-1019; Zhang, Y., Yuan, F., Wu, X., and Wang, Z. (2000) Mol. Cell. Biol. 20, 7099-7108). Here, we report on its ability to extend all 12 possible mispairs and 4 correct pairs in different sequence contexts. Extension from both matched and mismatched primer termini is generally most efficient and accurate when A is the next template base. In contrast, extension occurs less efficiently and accurately when T is the target template base. A striking exception occurs during extension of a G:T mispair, where the enzyme switches specificity, "preferring" to make a correct A:T base pair immediately downstream from an originally favored G:T mispair. Polymerase iota generates a variety of single and tandem mispairs with high frequency, implying that it may act as a strong mutator when copying undamaged DNA templates in vivo. Even so, its limited ability to catalyze extension from a relatively stable primer/template containing a "buried" mismatch suggests that polymerase iota-catalyzed errors are confined to short template regions.

Altered nucleotide misinsertion fidelity associated with poliota-dependent replication at the end of a DNA template.

A hallmark of human DNA polymerase iota (poliota) is the asymmetric fidelity of replication at template A and T when the enzyme extends primers annealed to a single-stranded template. Here, we report on the efficiency and accuracy of poliota-dependent replication at a nick, a gap, the very end of a template and from a mispaired primer. Poliota cannot initiate synthesis on a nicked DNA substrate, but fills short gaps efficiently. Surprisingly, poliota's ability to blunt-end a 1 bp recessed terminus is dependent upon the template nucleotide encountered and is highly erroneous. At template G, both C and T are inserted with roughly equal efficiency, whilst at template C, C and A are misinserted 8- and 3-fold more often than the correct base, G. Using substrates containing mispaired primer termini, we show that poliota can extend all 12 mispairs, but with differing efficiencies. Poliota can also extend a tandem mispair, especially when it is located within a short gap. The enzymatic properties of poliota appear consistent with that of a somatic hypermutase and suggest that poliota may be one of the low-fidelity DNA polymerases hypothesized to participate in the hypermutation of immunoglobulin variable genes in vivo.

Biochemical characterization of human DNA polymerase iota provides clues to its biological function.

The human RAD30B gene has recently been shown to encode a novel DNA polymerase, DNA polymerase iota (poliota). The role of poliota within the cell is presently unknown, and the only clues to its cellular function come from its biochemical characterization in vitro. The aim of this short review is, therefore, to summarize the known enzymic activities of poliota and to speculate as to how these biochemical properties might relate to its in vivo function.

5'-Deoxyribose phosphate lyase activity of human DNA polymerase iota in vitro.

DNA polymerase iota (pol iota) is one of several recently discovered DNA polymerases in mammalian cells whose function is unknown. We report here that human pol iota has an intrinsic 5'-deoxyribose phosphate (dRP) lyase activity. In reactions reconstituted with uracil-DNA glycosylase (UDG), apurinic/apyrimidinic (AP) endonuclease and DNA ligase I, pol iota can use its dRP lyase and polymerase activities to repair G*U and A*U pairs in DNA. These data and three distinct catalytic properties of pol iota implicate it in specialized forms of base excision repair (BER).

DNA polymerase iota and related rad30-like enzymes.

Until recently, the molecular mechanisms of translesion DNA synthesis (TLS), a process whereby a damaged base is used as a template for continued replication, was poorly understood. This area of scientific research has, however, been revolutionized by the finding that proteins long implicated in TLS are, in fact, DNA polymerases. Members of this so-called UmuC/DinB/Rev1/Rad30 superfamily of polymerases have been identified in prokaryotes, eukaryotes and archaea. Biochemical studies with the highly purified polymerases reveal that some, but not all, can traverse blocking lesions in template DNA. All of them share a common feature, however, in that they exhibit low fidelity when replicating undamaged DNA. Of particular interest to us is the Rad30 subfamily of polymerases found exclusively in eukaryotes. Humans possess two Rad30 paralogs, Rad30A and Rad30B. The RAD30A gene encodes DNA polymerase eta and defects in the protein lead to the xeroderma pigmentosum variant (XP-V) phenotype in humans. Very recently RAD30B has also been shown to encode a novel DNA polymerase, designated as Pol iota. Based upon in vitro studies, it appears that Pol iota has the lowest fidelity of any eukaryotic polymerase studied to date and we speculate as to the possible cellular functions of such a remarkably error-prone DNA polymerase.

Misinsertion and bypass of thymine-thymine dimers by human DNA polymerase iota.

Human DNA polymerase iota (pol(iota)) is a recently discovered enzyme that exhibits extremely low fidelity on undamaged DNA templates. Here, we show that poliota is able to facilitate limited translesion replication of a thymine-thymine cyclobutane pyrimidine dimer (CPD). More importantly, however, the bypass event is highly erroneous. Gel kinetic assays reveal that pol(iota) misinserts T or G opposite the 3' T of the CPD approximately 1.5 times more frequently than the correct base, A. While pol(iota) is unable to extend the T.T mispair significantly, the G.T mispair is extended and the lesion completely bypassed, with the same efficiency as that of the correctly paired A. T base pair. By comparison, pol(iota) readily misinserts two bases opposite a 6-4 thymine-thymine pyrimidine-pyrimidone photoproduct (6-4PP), but complete lesion bypass is only a fraction of that observed with the CPD. Our data indicate, therefore, that poliota possesses the ability to insert nucleotides opposite UV photoproducts as well as to perform unassisted translesion replication that is likely to be highly mutagenic.

poliota, a remarkably error-prone human DNA polymerase.

The Saccharomyces cerevisiae RAD30 gene encodes DNA polymerase eta. Humans possess two Rad30 homologs. One (RAD30A/POLH) has previously been characterized and shown to be defective in humans with the Xeroderma pigmentosum variant phenotype. Here, we report experiments demonstrating that the second human homolog (RAD30B), also encodes a novel DNA polymerase that we designate poliota. poliota, is a distributive enzyme that is highly error-prone when replicating undamaged DNA. At template G or C, the average error frequency was approximately 1 x 10(-2). Our studies revealed, however, a striking asymmetry in misincorporation frequency at template A and T. For example, template A was replicated with the greatest accuracy, with misincorporation of G, A, or C occurring with a frequency of approximately 1 x 10(-4) to 2 x 10(-4). In dramatic contrast, most errors occurred at template T, where the misincorporation of G was, in fact, favored approximately 3:1 over the correct nucleotide, A, and misincorporation of T occurred at a frequency of approximately 6.7 x 10(-1). These findings demonstrate that poliota is one of the most error-prone eukaryotic polymerases reported to date and exhibits an unusual misincorporation spectrum in vitro.

Visualization of two binding sites for the Escherichia coli UmuD'(2)C complex (DNA pol V) on RecA-ssDNA filaments.

The heterotrimeric UmuD'(2)C complex of Escherichia coli has recently been shown to possess intrinsic DNA polymerase activity (DNA pol V) that facilitates error-prone translesion DNA synthesis (SOS mutagenesis). When overexpressed in vivo, UmuD'(2)C also inhibits homologous recombination. In both activities, UmuD'(2)C interacts with RecA nucleoprotein filaments. To examine the biochemical and structural basis of these reactions, we have analyzed the ability of the UmuD'(2)C complex to bind to RecA-ssDNA filaments in vitro. As estimated by a gel retardation assay, binding saturates at a stoichiometry of approximately one complex per two RecA monomers. Visualized by cryo-electron microscopy under these conditions, UmuD'(2)C is seen to bind uniformly along the filaments, such that the complexes are completely submerged in the deep helical groove. This mode of binding would impede access to DNA in a RecA filament, thus explaining the ability of UmuD'(2)C to inhibit homologous recombination. At sub-saturating binding, the distribution of UmuD'(2)C complexes along RecA-ssDNA filaments was characterized by immuno-gold labelling with anti-UmuC antibodies. These data revealed preferential binding at filament ends (most likely, at one end). End-specific binding is consistent with genetic models whereby such binding positions the UmuD'(2)C complex (pol V) appropriately for its role in SOS mutagenesis.

UmuD'(2)C is an error-prone DNA polymerase, Escherichia coli pol V.

The damage-inducible UmuD' and UmuC proteins are required for most SOS mutagenesis in Escherichia coli. Our recent assay to reconstitute this process in vitro, using a native UmuD'(2)C complex, revealed that the highly purified preparation contained DNA polymerase activity. Here we eliminate the possibility that this activity is caused by a contaminating DNA polymerase and show that it is intrinsic to UmuD'(2)C. E. coli dinB has recently been shown to have DNA polymerase activity (pol IV). We suggest that UmuD'(2)C, the fifth DNA polymerase discovered in E. coli, be designated as E. coli pol V. In the presence of RecA, beta sliding clamp, gamma clamp loading complex, and E. coli single-stranded binding protein (SSB), pol V's polymerase activity is highly "error prone" at both damaged and undamaged DNA template sites, catalyzing efficient bypass of abasic lesions that would otherwise severely inhibit replication by pol III holoenzyme complex (HE). Pol V bypasses a site-directed abasic lesion with an efficiency about 100- to 150-fold higher than pol III HE. In accordance with the "A-rule," dAMP is preferentially incorporated opposite the lesion. A pol V mutant, UmuD'(2)C104 (D101N), has no measurable lesion bypass activity. A kinetic analysis shows that addition of increasing amounts of pol III to a fixed level of pol V inhibits lesion bypass, demonstrating that both enzymes compete for free 3'-OH template-primer ends. We show, however, that despite competition for primer-3'-ends, pol V and pol III HE can nevertheless interact synergistically to stimulate synthesis downstream from a template lesion.

Lon-mediated proteolysis of the Escherichia coli UmuD mutagenesis protein: in vitro degradation and identification of residues required for proteolysis.

Most SOS mutagenesis in Escherichia coli is dependent on the UmuD and UmuC proteins. Perhaps as a consequence, the activity of these proteins is exquisitely regulated. The intracellular level of UmuD and UmuC is normally quite low but increases dramatically in lon- strains, suggesting that both proteins are substrates of the Lon protease. We report here that the highly purified UmuD protein is specifically degraded in vitro by Lon in an ATP-dependent manner. To identify the regions of UmuD necessary for Lon-mediated proteolysis, we performed 'alanine-stretch' mutagenesis on umuD and followed the stability of the mutant protein in vivo. Such an approach allowed us to localize the site(s) within UmuD responsible for Lon-mediated proteolysis. The primary signal is located between residues 15 and 18 (FPLF), with an auxiliary site between residues 26 and 29 (FPSP), of the amino terminus of UmuD. Transfer of the amino terminus of UmuD (residues 1-40) to an otherwise stable protein imparts Lon-mediated proteolysis, thereby indicating that the amino terminus of UmuD is sufficient for Lon recognition and the ensuing degradation of the protein.

Structural insights into the regulation of SOS mutagenesis.

The Escherichia coli Umu proteins are best characterized by their role in damage inducible mutagenesis. Recently, we discovered that the intracellular levels of the UmuD and UmuC proteins are kept to a minimum by the Lon serine protease. Studies with the Salmonella typhimurium UmuD protein (which is 73% homologous with its E. coli counterpart) revealed that it too is degraded by Lon, suggesting that both UmuD proteins share conserved structural motifs. In contrast, E. coli UmuD' is removed from the cell by the ClpXP serine protease, but only when it is in a heterodimer complex with UmuD. We have generated deletion mutants of UmuD' and have coexpressed the mutant proteins with UmuD1 (a non-cleavable UmuD protein). By assaying the sensitivity of the mutant UmuD'-UmuD1 complex to ClpXP, we have been able to map regions of UmuD' that appear essential for efficient UmuD'-UmuD heterodimer formation. Previous experiments have suggested that the in vivo posttranslational processing of UmuD to UmuD' is inefficient. We have, however, discovered that limited cleavage occurs in an undamaged cell, but that these small amounts of UmuD' are rapidly degraded by ClpXP, thus giving rise to the appearance of inefficient cleavage. The ClpXP protease therefore plays dual roles in regulating SOS mutagenesis: it keeps the basal levels of UmuD' to a minimum in undamaged cells but it also acts in damaged cells to reduce the elevated levels of mutagenically active UmuD' protein, thereby returning the cell to a resting non-mutable state.