Toward the understanding of DSG2 and CD46 interaction with HAdV-11 fiber, a super-complex analysis

IMPORTANCE

The main limitation of oncolytic vectors is neutralization by blood components, which prevents intratumoral administration to patients. Enadenotucirev, a chimeric HAdV-11p/HAdV-3 adenovirus identified by bio-selection, is a low seroprevalence vector active against a broad range of human carcinoma cell lines. At this stage, there's still some uncertainty about tropism and primary receptor utilization by HAdV-11. However, this information is very important, as it has a direct influence on the effectiveness of HAdV-11-based vectors. The aim of this work is to determine which of the two receptors, DSG2 and CD46, is involved in the attachment of the virus to the host, and what role they play in the early stages of infection.

Translational development of a tumor junction opening technology

Our goal is to overcome treatment resistance in ovarian cancer patients which occurs in most cases after an initial positive response to chemotherapy. A central resistance mechanism is the maintenance of desmoglein-2 (DSG2) positive tight junctions between malignant cells that prevents drug penetration into the tumor. We have generated JO4, a recombinant protein that binds to DSG2 resulting in the transient opening of junctions in epithelial tumors. Here we present studies toward the clinical translation of c-JO4 in combination with PEGylated liposomal doxorubicin/Doxil for ovarian cancer therapy. A manufacturing process for cGMP compliant production of JO4 was developed resulting in c-JO4. GLP toxicology studies using material from this process in DSG2 transgenic mice and cynomolgus macaques showed no treatment-related toxicities after intravenous injection at doses reaching 24 mg/kg. Multiple cycles of intravenous c-JO4 plus Doxil (four cycles, 4 weeks apart, simulating the treatment regimen in the clinical trial) elicited antibodies against c-JO4 that increased with each cycle and were accompanied by elevation of pro-inflammatory cytokines IL-6 and TNFα. Pretreatment with steroids and cyclophosphamide reduced anti-c-JO4 antibody response and blunted cytokine release. Our data indicate acceptable safety of our new treatment approach if immune reactions are monitored and counteracted with appropriate immune suppression.

Elicitation of potent SARS-CoV-2 neutralizing antibody responses through immunization with a versatile adenovirus-inspired multimerization platform

Virus-like particles (VLPs) are highly suited platforms for protein-based vaccines. In the present work, we adapted a previously designed non-infectious adenovirus-inspired 60-mer dodecahedric VLP (ADDomer) to display a multimeric array of large antigens through a SpyTag/SpyCatcher system. To validate the platform as a potential COVID-19 vaccine approach, we decorated the newly designed VLP with the glycosylated receptor binding domain (RBD) of SARS-CoV-2. Cryoelectron microscopy structure revealed that up to 60 copies of this antigenic domain could be bound on a single ADDomer particle, with the symmetrical arrangements of a dodecahedron. Mouse immunization with the RBD decorated VLPs already showed a significant specific humoral response following prime vaccination, greatly reinforced by a single boost. Neutralization assays with SARS-CoV-2 spike pseudo-typed virus demonstrated the elicitation of strong neutralization titers, superior to those of COVID-19 convalescent patients. Notably, the presence of pre-existing immunity against the adenoviral-derived particles did not hamper the immune response against the antigen displayed on its surface. This plug and play vaccine platform represents a promising new highly versatile tool to combat emergent pathogens.

The Adenovirus Dodecahedron: Beyond the Platonic Story

Many geometric forms are found in nature, some of them adhering to mathematical laws or amazing aesthetic rules. One of the best-known examples in microbiology is the icosahedral shape of certain viruses with 20 triangular facets and 12 edges. What is less known, however, is that a complementary object displaying 12 faces and 20 edges called a 'dodecahedron' can be produced in huge amounts during certain adenovirus replication cycles. The decahedron was first described more than 50 years ago in the human adenovirus (HAdV3) viral cycle. Later on, the expression of this recombinant scaffold, combined with improvements in cryo-electron microscopy, made it possible to decipher the structural determinants underlying their architecture. Recently, this particle, which mimics viral entry, was used to fish the long elusive adenovirus receptor, desmoglein-2, which serves as a cellular docking for some adenovirus serotypes. This breakthrough enabled the understanding of the physiological role played by the dodecahedral particles, showing that icosahedral and dodecahedral particles live more than a simple platonic story. All these points are developed in this review, and the potential use of the dodecahedron in therapeutic development is discussed.

Intermediate-resolution crystal structure of the human adenovirus B serotype 3 fibre knob in complex with the EC2-EC3 fragment of desmoglein 2

The cryo-electron microscopy (cryo-EM) structure of the complex between the trimeric human adenovirus B serotype 3 fibre knob and human desmoglein 2 fragments containing cadherin domains EC2 and EC3 has been published, showing 3:1 and 3:2 complexes. Here, the crystal structure determined at 4.5 Å resolution is presented with one EC2-EC3 desmoglein fragment bound per fibre knob monomer in the asymmetric unit, leading to an apparent 3:3 stoichiometry. However, in concentrated solution the 3:2 complex is predominant, as shown by small-angle X-ray scattering (SAXS), while cryo-EM at lower concentrations showed a majority of the 3:1 complex. Substitution of the calcium ions bound to the desmoglein domains by terbium ions allowed confirmation of the X-ray model using their anomalous scattering and shows that at least one binding site per cluster of calcium ions is intact and exchangeable and, combined with SAXS data, that the cadherin domains are folded even in the distal part that is invisible in the cryo-EM reconstruction.

Remodeling of the Actin Network Associated with the Non-Structural Protein 1 (NS1) of West Nile Virus and Formation of NS1-Containing Tunneling Nanotubes

The cellular response to the recombinant NS1 protein of West Nile virus (NS1^WNV) was studied using three different cell types: Vero E6 simian epithelial cells, SH-SY5Y human neuroblastoma cells, and U-87MG human astrocytoma cells. Cells were exposed to two different forms of NS1^WNV: (i) the exogenous secreted form, sNS1^WNV, added to the extracellular milieu; and (ii) the endogenous NS1^WNV, the intracellular form expressed in plasmid-transfected cells. The cell attachment and uptake of sNS1^WNV varied with the cell type and were only detectable in Vero E6 and SH-SY5Y cells. Addition of sNS1^WNV to the cell culture medium resulted in significant remodeling of the actin filament network in Vero E6 cells. This effect was not observed in SH-SY5Y and U-87MG cells, implying that the cellular uptake of sNS1^WNV and actin network remodeling were dependent on cell type. In the three cell types, NS1^WNV-expressing cells formed filamentous projections reminiscent of tunneling nanotubes (TNTs). These TNT-like projections were found to contain actin and NS1^WNV proteins. Interestingly, similar actin-rich, TNT-like filaments containing NS1^WNV and the viral envelope glycoprotein E^WNV were also observed in WNV-infected Vero E6 cells.

Synthetic self-assembling ADDomer platform for highly efficient vaccination by genetically encoded multiepitope display

Self-assembling virus-like particles represent highly attractive tools for developing next-generation vaccines and protein therapeutics. We created ADDomer, an adenovirus-derived multimeric protein-based self-assembling nanoparticle scaffold engineered to facilitate plug-and-play display of multiple immunogenic epitopes from pathogens. We used cryo-electron microscopy at near-atomic resolution and implemented novel, cost-effective, high-performance cloud computing to reveal architectural features in unprecedented detail. We analyzed ADDomer interaction with components of the immune system and developed a promising first-in-kind ADDomer-based vaccine candidate to combat emerging Chikungunya infectious disease, exemplifying the potential of our approach.

Structure-based Design of JOC-x, a Conjugatable Tumor Tight Junction Opener to Enhance Cancer Therapy

Disorganized intercellular junctions are critical for maintaining the integrity of solid epithelial tumors and prevent the infiltration of oncological therapies into the bulk of the malignancy. We have developed small, recombinant proteins which bind a critical junction protein, desmoglein 2, triggering the transient and specific opening of tumor tight junctions allowing for infiltration of the tumor with immune cells, oncolytic viruses, drugs, and other therapeutics. Our new molecule, JOC-x, is a promising candidate for a new class of tumor-targeting agents that accumulate both around and within tumors and remodel the tumor microenvironment. Native cysteines were removed from the parental protein, JO-4, followed by addition of a single cysteine to allow for convenient attachment of various payloads that can be targeted directly to the tumor. Our tumor-targeting protein exhibits high avidity, minimal aggregation, and is easily purified at good yields from E. coli. For proof of concept, we demonstrate effective conjugation to biotin as a model for flexible co-targeting, addition of metal ion chelators as models for imaging and radiotherapy, and linkage of the TLR3 agonist poly(I:C) as a model immune-oncologic agent. This second-generation cancer co-therapeutic protein is optimized for activity and primed for cGMP manufacture in preparation for upcoming clinical studies.

Mapping of Adenovirus of serotype 3 fibre interaction to desmoglein 2 revealed a novel 'non-classical' mechanism of viral receptor engagement

High-affinity binding of the trimeric fibre protein to a cell surface primary receptor is a common feature shared by all adenovirus serotypes. Recently, a long elusive species B adenovirus receptor has been identified. Desmoglein 2 (DSG2) a component of desmosomal junction, has been reported to interact at high affinity with Human adenoviruses HAd3, HAd7, HAd11 and HAd14. Little is known with respect to the molecular interactions of adenovirus fibre with the DSG2 ectodomain. By using different DSG2 ectodomain constructs and biochemical and biophysical experiments, we report that the third extracellular cadherin domain (EC3) of DSG2 is critical for HAd3 fibre binding. Unexpectedly, stoichiometry studies using multi-angle laser light scattering (MALLS) and analytical ultra-centrifugation (AUC) revealed a non-classical 1:1 interaction (one DSG2 per trimeric fibre), thus differentiating ‘DSG2-interacting’ adenoviruses from other protein receptor interacting adenoviruses in their infection strategy.

In Vivo Quantification of 5-HT2A Brain Receptors in Mdr1a KO Rats with 123I-R91150 Single-Photon Emission Computed Tomography

Our goal was to identify suitable image quantification methods to image 5-hydroxytryptamine2A (5-HT2A) receptors in vivo in Mdr1a knockout (KO) rats (i.e., P-glycoprotein KO) using 123I-R91150 single-photon emission computed tomography (SPECT). The 123I-R91150 binding parameters estimated with different reference tissue models (simplified reference tissue model [SRTM], Logan reference tissue model, and tissue ratio [TR] method) were compared to the estimates obtained with a comprehensive three-tissue/seven-parameter (3T/7k)-based model. The SRTM and Logan reference tissue model estimates of 5-HT2A receptor (5-HT2AR) nondisplaceable binding potential (BPND) correlated well with the absolute receptor density measured with the 3T/7k gold standard (r > .89). Quantification of 5-HT2AR using the Logan reference tissue model required at least 90 minutes of scanning, whereas the SRTM required at least 110 minutes. The TR method estimates were also highly correlated to the 5-HT2AR density (r > .91) and only required a single 20-minute scan between 100 and 120 minutes postinjection. However, a systematic overestimation of the BPND values was observed. The Logan reference tissue method is more convenient than the SRTM for the quantification of 5-HT2AR in Mdr1a KO rats using 123I-R91150 SPECT. The TR method is an interesting and simple alternative, despite its bias, as it still provides a valid index of 5-HT2AR density.

Crystal Structure of the Vaccinia Virus Uracil-DNA Glycosylase in Complex with DNA

Vaccinia virus polymerase holoenzyme is composed of the DNA polymerase catalytic subunit E9 associated with its heterodimeric co-factor A20·D4 required for processive genome synthesis. Although A20 has no known enzymatic activity, D4 is an active uracil-DNA glycosylase (UNG). The presence of a repair enzyme as a component of the viral replication machinery suggests that, for poxviruses, DNA synthesis and base excision repair is coupled. We present the 2.7 Å crystal structure of the complex formed by D4 and the first 50 amino acids of A20 (D4·A201-50) bound to a 10-mer DNA duplex containing an abasic site resulting from the cleavage of a uracil base. Comparison of the viral complex with its human counterpart revealed major divergences in the contacts between protein and DNA and in the enzyme orientation on the DNA. However, the conformation of the dsDNA within both structures is very similar, suggesting a dominant role of the DNA conformation for UNG function. In contrast to human UNG, D4 appears rigid, and we do not observe a conformational change upon DNA binding. We also studied the interaction of D4·A201-50 with different DNA oligomers by surface plasmon resonance. D4 binds weakly to nonspecific DNA and to uracil-containing substrates but binds abasic sites with a Kd of <1.4 μm. This second DNA complex structure of a family I UNG gives new insight into the role of D4 as a co-factor of vaccinia virus DNA polymerase and allows a better understanding of the structural determinants required for UNG action.

Human full-length coagulation factor X and a GLA domain-derived 40-mer polypeptide bind to different regions of the adenovirus serotype 5 hexon capsomer

The interaction of human adenovirus (HAdV)-C5 and many other adenoviruses with blood coagulation factors (e.g., human factor X, FX) involves the binding of their GLA domain to the hexon capsomers, resulting in high levels of hepatotropism and potential hepatotoxicity. In this study, we tested the possibility of preventing these undesirable effects by using a GLA-mimicking peptide as a competitor. An FX GLA domain-derived, 40-mer polypeptide carrying 12 carboxyglutamate residues was synthesized (GLA(mim)). Surface plasmon resistance (SPR) analysis showed that GLA(mim) reacted with free and capsid-embedded hexon with a nanomolar affinity. Unexpectedly, GLA(mim) failed to compete with FX for hexon binding, and instead significantly increased the formation of FX-hexon or FX-adenovirion complexes. This observation was confirmed by in vitro cell transduction experiments using HAdV-C5-Luciferase vector (HAdV5-Luc), as preincubation of HAdV5-Luc with GLA(mim) before FX addition resulted in a higher transgene expression compared with FX alone. HAdV-C5 virions complexed with GLA(mim) were analyzed by cryoelectron microscopy. Image reconstruction demonstrated the bona fide hexon-GLA(mim) interaction, as for the full-length FX, although with considerable differences in stoichiometry and relative location on the hexon capsomer. Three extra densities were found at the periphery of each hexon, whereas one single FX molecule occupied the central cavity of the hexon trimeric capsomer. A refined analysis indicated that each extra density is found at the expected location of one highly variable loop 1 of the hexon, involved in scavenger receptor recognition. HAdV5-Luc complexed with a bifunctional GLA(mim)RGD peptide showed a lesser hepatotropism, compared with control HAdV5-Luc alone, and efficiently targeted αβ-integrin-overexpressing tumor cells in an in vivo mouse tumor model. Collectively, our findings open new perspectives in the design of adenoviral vectors for biotherapy.

Use of dodecahedron "VLPs" as an alternative to the whole adenovirus

During human adenovirus type 3 (Ad3) infection, an excess of penton base and fiber proteins are produced. These form dodecahedral particles composed of 12 pentamers of penton base and 12 trimers of fiber protein. Beside this "natural" expression, the adenovirus dodecahedron can be expressed in the heterologous baculovirus system in two forms: a fiber-devoid dodecahedron made only of 12 penton bases (called base-dodecahedron: Bs-Dd) and the fiber-containing dodecahedron (called penton dodecahedron: Pt-Dd). These particles partly mimic the adenoviral cellular entry pathway but are devoid of genetic information making them an unusual tool for basic research or applications. We report here how these particles are expressed and purified, the labeling method for trafficking studies as well as their use in molecular interaction studies. The potential of these particles for biotechnological applications is under evaluation, making their study a "niche" along side traditional adenoviral vectors.

The structural basis for the integrity of adenovirus Ad3 dodecahedron

During the viral life cycle adenoviruses produce excess capsid proteins. Human adenovirus serotype 3 (Ad3) synthesizes predominantly an excess of free pentons, the complexes of pentameric penton base and trimeric fiber proteins, which are responsible for virus penetration. In infected cells Ad3 pentons spontaneously assemble into dodecahedral virus-like nano-particles containing twelve pentons. They also form in insect cells during expression in the baculovirus system. Similarly, in the absence of fiber protein dodecahedric particles built of 12 penton base pentamers can be produced. Both kinds of dodecahedra show remarkable efficiency of intracellular penetration and can be engineered to deliver several millions of foreign cargo molecules to a single target cell. For this reason, they are of great interest as a delivery vector. In order to successfully manipulate this potential vector for drug and/or gene delivery, an understanding of the molecular basis of vector assembly and integrity is critical. Crystallographic data in conjunction with site-directed mutagenesis and biochemical analysis provide a model for the molecular determinants of dodecamer particle assembly and the requirements for stability. The 3.8 Å crystal structure of Ad3 penton base dodecamer (Dd) shows that the dodecahedric structure is stabilized by strand-swapping between neighboring penton base molecules. Such N-terminal strand-swapping does not occur for Dd of Ad2, a serotype which does not form Dd under physiological conditions. This unique stabilization of the Ad3 dodecamer is controlled by residues 59-61 located at the site of strand switching, the residues involved in putative salt bridges between pentamers and by the disordered N-terminus (residues 1-47), as confirmed by site directed mutagenesis and biochemical analysis of mutant and wild type protein. We also provide evidence that the distal N-terminal residues are externally exposed and available for attaching cargo.

A new human DSG2-transgenic mouse model for studying the tropism and pathology of human adenoviruses

We have recently reported that a group of human adenoviruses (HAdVs) uses desmoglein 2 (DSG2) as a receptor for infection. Among these are the widely distributed serotypes HAdV-B3 and HAdV-B7, as well as a newly emerged strain derived from HAdV-B14. These serotypes do not infect rodent cells and could not up until now be studied in small-animal models. We therefore generated transgenic mice containing the human DSG2 locus. These mice expressed human DSG2 (hDSG2) at a level and in a pattern similar to those found for humans and nonhuman primates. As an initial application of hDSG2-transgenic mice, we used a green fluorescent protein (GFP)-expressing HAdV-B3 vector (Ad3-GFP) and studied GFP transgene expression by quantitative reverse transcription-PCR (qRT-PCR) and immunohistochemistry subsequent to intranasal and intravenous virus application. After intranasal application, we found efficient transduction of bronchial and alveolar epithelial cells in hDSG2-transgenic mice. Intravenous Ad3-GFP injection into hDSG2-transgenic mice resulted in hDSG2-dependent transduction of epithelial cells in the intestinal and colon mucosa. Our findings give an explanation for clinical symptoms associated with infection by DSG2-interacting HAdVs and provide a rationale for using Ad3-derived vectors in gene therapy.

Generation and biological properties of a recombinant dodecahedron containing the short fiber protein of the human adenovirus 41

OBJECTIVE

In order to gain further insight into the function of the enteric adenovirus short fiber (SF), we have constructed a recombinant dodecahedron containing the SF protein of HAdV-41 and the HAdV-3 penton base.

METHODS

Recombinant baculoviruses expressing the HAdV-41 SF protein and HAdV-3 penton base were cloned and amplified in Sf9 insect cells. Recombinant dodecahedra were expressed by coinfection of High Five™ cells with both baculoviruses, 72 h post-infection. Cell lysate was centrifuged on sucrose density gradient and the purified recombinant dodecahedra were recovered.

RESULTS

Analysis by negative staining electron microscopy demonstrated that chimeric dodecahedra made of the HAdV-3 penton base and decorated with the HAdV-41 SF were successfully generated. Next, recombinant dodecahedra were digested with pepsin and analyzed by Western blot. A 'site-specific' proteolysis of the HAdV-41 SF was observed, while the HAdV-3 penton base core was completely digested.

CONCLUSION

These results show that, in vitro, the HAdV-41 SF likely undergoes proteolysis in the gastrointestinal tract, its natural environment, which may facilitate the recognition of receptors in intestinal cells. The results obtained in the present study may be the basis for the development of gene therapy vectors towards the intestinal epithelium, as well as orally administered vaccine vectors, but also for the HAdV-41 SF partner identification.

Epithelial junction opener JO-1 improves monoclonal antibody therapy of cancer

The efficacy of monoclonal antibodies (mAb) used to treat solid tumors is limited by intercellular junctions which tightly link epithelial tumor cells to each another. In this study, we define a small, recombinant adenovirus serotype 3-derived protein, termed junction opener 1 (JO-1), which binds to the epithelial junction protein desmoglein 2 (DSG2). In mouse xenograft models employing Her2/neu- and EGFR-positive human cancer cell lines, JO-1 mediated cleavage of DSG2 dimers and activated intracellular signaling pathways which reduced E-cadherin expression in tight junctions. Notably, JO-1-triggered changes allowed for increased intratumoral penetration of the anti-Her2/neu mAb trastuzumab (Herceptin) and improved access to its target receptor, Her2/neu, which is partly trapped in tight junctions. This effect translated directly into increased therapeutic efficacy of trastuzumab in mouse xenograft models using breast, gastric, and ovarian cancer cells that were Her2/neu-positive. Furthermore, combining JO-1 with the EGFR-targeting mAb cetuximab (Erbitux) greatly improved therapeutic outcomes in a metastatic model of EGFR-positive lung cancer. A combination of JO-1 with an approach that triggered transient degradation of tumor stroma proteins elicited eradication of tumors. Taken together, our findings offer preclinical proof of concept to employ JO-1 in combination with mAb therapy.

A fiber-modified adenoviral vector interacts with immunoevasion molecules of the B7 family at the surface of murine leukemia cells derived from dormant tumors

Tumor cells can escape the immune system by overexpressing molecules of the B7 family, e.g. B7-H1 (PD-L1 or CD86), which suppresses the anti-tumor T-cell responses through binding to the PD-1 receptor, and similarly for B7.1 (CD80), through binding to CTLA-4. Moreover, direct interactions between B7-H1 and B7.1 molecules are also likely to participate in the immunoevasion mechanism. In this study, we used a mouse model of tumor dormancy, DA1-3b leukemia cells. We previously showed that a minor population of DA1-3b cells persists in equilibrium with the immune system for long periods of time, and that the levels of surface expression of B7-H1 and B7.1 molecules correlates with the dormancy time. We found that leukemia cells DA1-3b/d365 cells, which derived from long-term dormant tumors and overexpressed B7-H1 and B7.1 molecules, were highly permissive to Ad5FB4, a human adenovirus serotype 5 (Ad5) vector pseudotyped with chimeric human-bovine fibers. Both B7-H1 and B7.1 were required for Ad5FB4-cell binding and entry, since (i) siRNA silencing of one or the other B7 gene transcript resulted in a net decrease in the cell binding and Ad5FB4-mediated transduction of DA1-3b/d365; and (ii) plasmid-directed expression of B7.1 and B7-H1 proteins conferred to Ad5FB4-refractory human cells a full permissiveness to this vector. Binding data and flow cytometry analysis suggested that B7.1 and B7-H1 molecules played different roles in Ad5FB4-mediated transduction of DA1-3b/d365, with B7.1 involved in cell attachment of Ad5FB4, and B7-H1 in Ad5FB4 internalization. BRET analysis showed that B7.1 and B7-H1 formed heterodimeric complexes at the cell surface, and that Ad5FB4 penton, the viral capsomere carrying the fiber projection, could negatively interfere with the formation of B7.1/B7-H1 heterodimers, or modify their conformation. As interactors of B7-H1/B7.1 molecules, Ad5FB4 particles and/or their penton capsomeres represent potential therapeutic agents targeting cancer cells that had developed immunoevasion mechanisms.

Cell entry and trafficking of human adenovirus bound to blood factor X is determined by the fiber serotype and not hexon:heparan sulfate interaction

Human adenovirus serotype 5 (HAdV5)-based vectors administered intravenously accumulate in the liver as the result of their direct binding to blood coagulation factor X (FX) and subsequent interaction of the FX-HAdV5 complex with heparan sulfate proteoglycan (HSPG) at the surface of liver cells. Intriguingly, the serotype 35 fiber-pseudotyped vector HAdV5F35 has liver transduction efficiencies 4-logs lower than HAdV5, even though both vectors carry the same hexon capsomeres. In order to reconcile this apparent paradox, we investigated the possible role of other viral capsid proteins on the FX/HSPG-mediated cellular uptake of HAdV5-based vectors. Using CAR- and CD46-negative CHO cells varying in HSPG expression, we confirmed that FX bound to serotype 5 hexon protein and to HAdV5 and HAdV5F35 virions via its Gla-domain, and enhanced the binding of both vectors to surface-immobilized hypersulfated heparin and cellular HSPG. Using penton mutants, we found that the positive effect of FX on HAdV5 binding to HSPG and cell transduction did not depend on the penton base RGD and fiber shaft KKTK motifs. However, we found that FX had no enhancing effect on the HAdV5F35-mediated cell transduction, but a negative effect which did not involve the cell attachment or endocytic step, but the intracellular trafficking and nuclear import of the FX-HAdV5F35 complex. By cellular imaging, HAdV5F35 particles were observed to accumulate in the late endosomal compartment, and were released in significant amounts into the extracellular medium via exocytosis. We showed that the stability of serotype 5 hexon:FX interaction was higher at low pH compared to neutral pH, which could account for the retention of FX-HAdV5F35 complexes in the late endosomes. Our results suggested that, despite the high affinity interaction of hexon capsomeres to FX and cell surface HSPG, the adenoviral fiber acted as the dominant determinant of the internalization and trafficking pathway of HAdV5-based vectors.

Desmoglein 2 is a receptor for adenovirus serotypes 3, 7, 11 and 14

We have identified desmoglein 2 (DSG2) as the primary high-affinity receptor used by adenovirus (Ad) serotypes Ad3, Ad7, Ad11, and Ad14. These serotypes represent important human pathogens causing respiratory tract infections. In epithelial cells, adenovirus binding to DSG2 triggers events reminiscent of epithelial-to-mesenchymal transition, leading to transient opening of intercellular junctions. This improves access to receptors, e.g. CD46 and Her2/neu, that are trapped in intercellular junctions. In addition to complete virions, dodecahedral particles (PtDd), formed by viral penton and fiber in excess during viral replication, can trigger DSG2-mediated opening of intercellular junctions as shown by studies with recombinant Ad3 PtDd. Our findings shed light on adenovirus biology and pathogenesis and have implications for cancer therapy.

Influence of chimeric human-bovine fibers on adenoviral uptake by liver cells and the antiviral immune response

Human adenoviruses (HAdV) are widely used for in vitro and in vivo gene transfer. Viral hepatotropism, inflammatory responses and neutralization by pre-existing antibodies (NAbs) are obstacles for clinical applications of HAdV vectors. Although the multifactorial events leading to innate HAdV toxicity are far from being elucidated, there is a consensus that the majority of intravenously injected-HAdV vectors is sequestered by Kuppfer cells, probably independently of coagulation factors. In this study, we show that the adenoviral-associated humoral and innate cytokine immune responses are significantly reduced when HAdV-5 vector carrying human bovine chimeric fibers (HAdV-5-F2/BAdV-4) is intravenously injected into mice. Fiber pseudotyping modified its interaction with blood coagulation factors, as FIX and FX no longer mediate the infection of liver cells by HAdV-5-F2/BAdV-4. As a consequence, at early time points post-infection, several cytokines and chemokines (IFN-gamma, IL-6, IP-10, MCP-1, RANTES and MP1beta) were found to be present at lower levels in the plasma of mice that had been intravenously injected with HAdV-5-F2/BAdV-4 compared with mice injected with the parental vector HAdV-5. Moreover, genetic modification of the fiber allowed HAdV-5-F2/BAdV-4 to partially escape neutralization by NAbs.

Infection kinetics of human adenovirus serotype 41 in HEK 293 cells

The purpose of this work was to acquire an overview of the infectious cycle of HAdV-41 in permissive HEK 293 cells and compare it to that observed with the prototype of the genus, Human adenovirus C HAdV-2. HEK 293 cells were infected with each virus separately and were harvested every 12 h for seven days. Infection kinetics were analysed using confocal and electronic microscopy. The results show that, when properly cultivated, HAdV-41 was not fastidious. It had a longer multiplication cycle, which resulted in the release of complete viral particles and viral stocks reached high titres. After 60 h of infection, the export of viral proteins from the infected cell to the extracellular milieu was observed, with a pattern similar to that previously described for HAdV-2 penton-base trafficking after 30 h of infection. HAdV-41 had a non-lytic cycle and the infection spread from the first infected cell to its neighbours. The release process of the viral particles is unknown. The results observed for HAdV-41 infection in HEK 293 cells show how different this virus is from the prototype HAdV-2 and provides information for the development of this vector for use in gene therapy.

[Adenoviruses structure]

Adenoviruses are double stranded DNA non enveloped viruses. Although these viruses are widely studied for gene therapy and anticancer applications, fundamental knowledge of these viruses, especially from a structural point of view is lacking. This is probably partly responsible for the limited success of the first clinical trials.With these viruses, one of the main conditions necessary to use adenoviruses for therapeutic application is structural modification of the virus. Indeed, one has to retarget the virus to specific tissues and/or remove all the immunogenic loops present on the outside of the virus in order to limit the host immune response. To make these changes rationally, the structure of the capsid has to be known at atomic resolution. Today, electron microscopy is the only tool that enables us to have access to the structure of the entire virus, but only at intermediate resolution. Because the atomic structures of the adenovirus major capsid proteins are known, one can combine these structures with the electron microscopy based envelope to calculate a model of the capsid at quasi-atomic resolution. These kinds of models are useful to visualize and understand the complexity of the virus. Nevertheless, the structure of the entire capsid at atomic resolution will really be necessary to use the virus in a safe way.

Adenovirus dodecahedron cell attachment and entry are mediated by heparan sulfate and integrins and vary along the cell cycle

The adenovirus penton base is a strategic protein involved in the virus internalisation pathway through interaction between its RGD sequences and integrin. In some human adenovirus serotypes, this pentameric protein features the ability of interacting together by twelve, leading to the formation of a symmetric nanoparticle called dodecahedron (Dd). This non-infectious adenovirus-like particle exhibiting sixty RGD sequences interacts with integrin but also with heparan sulfate proteoglycans (HSPGs) expressed at the cell surface. In this study, we discriminate the respective importance of HSPGs and integrin on human adenovirus serotype 3 dodecahedron attachment and entry. Using different cell lines and a specific integrin inhibitor, we have determined that HSPGs are mainly responsible for particle attachment to the cell surface, favouring a strictly required interaction with integrin that triggers internalisation. No other receptors are involved in Dd entry and integrins on their own can mediate the particle entry in HSPGs-deficient cells. Moreover, integrin recognition by Dd is highly susceptible to cations and particularly to manganese that enhances particle binding by 4- to 7-fold compared to calcium. Interestingly, investigations on Dd receptors along the cell cycle revealed an enhanced particle targeting to mitotic cells and a loss of internalisation at this stage. This phenomenon observed with both HeLa- and HSPGs-deficient cells, depends on integrin remodelling during mitosis. This provides new clues for the use of this adenovirus nanoparticle as a delivery vector and sheds light on the integrin and HSPGs relationship in both resting and dividing cells.

Development of the dodecahedral penton particle from adenovirus 3 for therapeutic application

The subviral dodecahedral particle of adenovirus 3, which assembles spontaneously in insect cells expressing the viral penton base protein, shows promise as a vector for drug delivery. Its ability to gain cell entry has been demonstrated and recent structural analysis has outlined details of the interfaces between penton bases and the importance of proteolysis of the penton base N terminus for assembly, providing a basis for understanding particle assembly and stability. Here, work in manipulating the assembly status of the dodecahedron by changing buffer conditions and subsequent success in passively encapsidating a marker molecule is described. This represents an important stage towards development of the dodecahedral particle for use as a delivery vehicle capable of targeting therapeutic molecules to specific cell types.

Protein transduction into human cells by adenovirus dodecahedron using WW domains as universal adaptors

BACKGROUND

Direct protein transduction is a recent technique that involves use of peptide vectors. In this study, we demonstrate that adenovirus dodecahedron (Dd), a virus-like particle devoid of DNA and able to penetrate cells with high efficiency, can be used as a vector for protein delivery.

METHODS

Taking advantage of Dd interaction with structural domains called WW, we have elaborated a universal adaptor to attach a protein of interest to this vector.

RESULTS

A tandem of three WW structural domains derived from the Nedd4 protein enables the formation of stable complexes with Dd, without impairing its endocytosis efficiency. Our protein of interest fused to the triple WW linker is delivered by the dodecahedron in 100% of cells in culture with on average more than ten million molecules per cell.

CONCLUSION

These data demonstrate the great potential of adenovirus dodecahedron in combination with WW domains as a protein transduction vector.

Heparan sulphate proteoglycans and viral vectors : ally or foe?

The attachment of viruses to the host cell surface is a critical stage that will largely condition cell permissivity and productive infection. The understanding of such mechanisms is therefore essential for gene therapy applications involving viruses, as this step will influence both targeting and delivery efficiency of the gene of interest. Viral attachment depends upon the recognition and binding of viral envelope/capsid proteins to specific cellular receptors that can be from very diverse origins. Amongst them are heparan sulphate proteoglycans (HSPGs), a family of glycoproteins which, through the large binding properties of their heparan sulphate (HS) polysaccharide chains, serve as attachment receptor for a great number of viruses. The aim of this review is to provide an update on the multiple roles of HSPGs during viral infection, with a special focus on viruses used as gene delivery vectors. Consequences of HS binding for gene therapy applications will be assessed, as well as the various strategies that have been developed to potentiate the advantages or to overcome the drawbacks resulting from viral vector interaction with HS.

Structure of the Dodecahedral Penton Particle from Human Adenovirus Type 3

The sub-viral dodecahedral particle of human adenovirus type 3, composed of the viral penton base and fiber proteins, shares an important characteristic of the entire virus: it can attach to cells and penetrate them. Structure determination of the fiberless dodecahedron by cryo-electron microscopy to 9 Angstroms resolution reveals tightly bound pentamer subunits, with only minimal interfaces between penton bases stabilizing the fragile dodecahedron. The internal cavity of the dodecahedron is approximately 80 Angstroms in diameter, and the interior surface is accessible to solvent through perforations of approximately 20 Angstroms diameter between the pentamer towers. We observe weak density beneath pentamers that we attribute to a penton base peptide including residues 38-48. The intact amino-terminal domain appears to interfere with pentamer-pentamer interactions and its absence by mutation or proteolysis is essential for dodecamer assembly. Differences between the 9 Angstroms dodecahedron structure and the adenovirus serotype 2 (Ad2) crystallographic model correlate closely with differences in sequence. The 3D structure of the dodecahedron including fibers at 16 Angstroms resolution reveals extra density on the top of the penton base that can be attributed to the fiber N terminus. The fiber itself exhibits striations that correlate with features of the atomic structure of the partial Ad2 fiber and that represent a repeat motif present in the amino acid sequence. These new observations offer important insights into particle assembly and stability, as well as the practicality of using the dodecahedron in targeted drug delivery. The structural work provides a sound basis for manipulating the properties of this particle and thereby enhancing its value for such therapeutic use.

Cellular uptake of the EBV transcription factor EB1/Zta

A number of viral proteins have the property to penetrate into the cells when present in the extra-cellular compartment. Here, we report that the Epstein-Barr virus (EBV) transcriptional activator EB1/Zta, which is responsible for the activation of the EBV lytic replication, binds to lymphoid cells surface, is efficiently translocated and accumulates in the nucleus. The internalization of EB1/Zta is energy-dependent and shares common features with endocytosis. As the EB1/Zta was not degraded in the cells and reached the nucleus, the potential effect of its internalisation on viral reactivation was assessed.

Synthesis, cellular localization, and quantification of penton-dodecahedron in serotype 3 adenovirus-infected cells

Adenovirus penton is a non-covalent complex composed of the penton base and fiber proteins, localized at the twelve vertices of the icosahedral virus capsid. In cells infected by adenovirus serotype 3 (Ad3), penton is found not only in the virus capsid but also self-assembled in dodecahedra formed through interactions between the twelve penton bases. In this study, the intracellular trafficking of penton proteins from the cytoplasm to the nucleus has been followed, and the nuclear re-arrangement induced by viral infection has been observed by electron microscopy of ultrathin sections. The amount of dodecahedra has been assessed in relation to the number of Ad3 infectious virions produced during the Ad3 replication cycle. It appears that dodecahedra are produced in a large excess over viral infectious particles and that they are located intranuclearly along the nuclear membrane of Ad3-infected cells at late times of infection.

La chirurgie de l'obésité en France : résultats d'une enquête prospective nationale

AIM

To compare the actual practice of bariatric surgery in France with the guidelines of scientific societies regarding surgical indications and followup.

METHODS

This a prospective descriptive transversal study performed within a two month period (December 2002 - January 2003) in all patients for which a consent demand has been sent to the Medical Insurance Services (examined by an administrative consultant) and/or patients operated on for morbid obesity (with or without administrative consent).

RESULTS

One thousand and three patients have been examined by an administrative consultant before obesity surgery and 1238 patients have been operated in 263 centres including 79 public (non-profit) centres and 184 private centres. In 16.7 % of the cases, there were wrong indications according to recognized criteria (BMI<35 kg/m(2) or lack of comorbidities for BMI between 35 and 39) or even contraindications because of other diseases. Patient informed consent was retrieved in only 54 % of medical files and follow up protocol was done in only 47 % of the cases. Because of several missing data, the practice of bariatric surgery followed the guidelines in only 34 % of cases. In hospital morbidity rate was 5 %. Two patients died postoperatively (mortality rate 0.2 %).

CONCLUSIONS

This study demonstrates that the practice of bariatric surgery needs to be improved in France.

The prevalence and cost of diabetes in metropolitan France: what trends between 1998 and 2000?*

OBJECTIVES

Our aim was to update available data concerning the prevalence and cost of diabetes in metropolitan France.

METHODS

We performed a retrospective study using patient reimbursement data from all the 128 local health offices (CPAM) in metropolitan France. We selected patients who received reimbursements for an oral hypoglycemic agent or insulin. Thus, 704,423 patients were studied by using 1998 data and 1,145,603 patients were studied by using data from 2000. The expenditures studied represented the total amount reimbursed by national health insurance to diabetic patients. The cost differential which could be attributed to diabetes was calculated by determining the difference between costs generated by diabetic patients to those generated by the rest of the population of the same age.

RESULTS

Between 1998 and 2000, the prevalence of diabetes treated in the population of affiliates covered by the general scheme increased from 2.78% to 2.96%. The total amount paid by the general scheme for care to diabetic patients (related to diabetes or not) was 5.710 billion euros in 2000 compared to 4.862 billion euros in 1998. The amount which can be attributed to diabetes alone can be estimated to be 2.414 billion euros in 2000 compared to 2.021 billion euros in 1998. After considering the impact of the increase in the number of treated diabetics, a modification in the modalities of medical care probably accounts for 183 million euros of the cost increase. Medical equipment (self blood glucose monitoring devices, reagent strips, finger lancets...) accounts for 39.3% (72 million euros) of this cost differential, medications account for 34.4% (63 million euros) and nursing care 16.9% (31 million euros). There was no change in the cost of diabetes with relation to expenses for medical consultations.

[A comparison of the management of severe high blood pressure between 1999 and 2003 in France]

AIM

To measure the change in blood-pressure control in two populations of patients with severe high blood pressure between 1999 and 2003.

METHOD

The French National Healthcare Fund performed two observational, cross-sectional surveys on the medical management of high blood pressure, the first in 1999 and the second in 2003. Each survey enrolled patients aged between 20 and 80 years old who filed a first-time request for exemption from co-payments for this long-term disorder. Study data was collected by the health fund's salaried physician advisors who directly examined the patients and from information gathered from each patient's attending physician. Adequate blood pressure control was defined according to the guidelines set out by the ANAES in 1997 and determined by calculating the average of the last three blood pressure figures recorded by the patient's attending physician (systolic [SBP] and diastolic [DBP] arterial blood pressures).

RESULTS

10,665 patients were enrolled in the 1999 survey and 2,584 were enrolled in the 2003 survey. The average age was 63.1 +/- 0.2 years in 1999 and 64.4 +/- 0.4 years in 2003. The proportion of diabetic patients in the two surveys remained stable: 27.5% +/- 1.0 in 1999 and 28.4% +/- 1.7 in 2003. Between 1999 and 2003, the percentage of patient who were treated for hypercholesterolemia increased from 44.0% +/- 1.1 to 54.3% +/- 1.9. Between 1999 and 2003, the proportion of patients who were considered well-controlled (SBP and DBP < 140/90 mmHg) or, if older than 60 years with isolated systolic high blood pressure (DBP < 90 mmHg and SBP < or = 160 mmHg) increased almost 5% points, going from 40.8% +/- 1.1 in 1999 to 45.5% +/- 1.9 in 2003. In diabetic patients, in whom the cut-off threshold is 130/85 mmHg, 6.7% +/- 1.1 were considered well-controlled in 1999 while 5.4% +/- 1.7 were deemed well-controlled in 2003. The proportion of well-controlled patients in the sub-group of hypertensive patients with renal failure (cut-off thresholds: 125/75 mmHg) remained relatively stable between 1999 and 2003: 5.2% [2.5; 7.9] versus 2.8% [0.5; 8.6].

CONCLUSION

There was a significant increase in the proportion of well-controlled hypertensive patients between 1999 and 2003. This increase occurred at the same time as a number of initiatives (scientific societies, federal government as well as the National Health Fund) intended to sensitize physicians to the need to obtain adequate blood pressure control.

Poneratoxin, a neurotoxin from ant venom

Poneratoxin is a small neuropeptide found in the venom of the ant Paraponera clavata. It is stored in the venom reservoir as an inactive 25-residue peptide. Here we describe both chemically synthesized poneratoxin and poneratoxin obtained by expression in insect cells. When expressed in insect cells, poneratoxin was observed attached to cell membranes. Both synthetic and recombinant ponerotoxins were soluble below pH 4.5. The structure of synthetic poneratoxin was characterized by circular dichroism and solved by nuclear magnetic resonance. In an environment imitating a lipid bilayer, at pH within the range of insect hemolymph, synthetic poneratoxin has a V shape, with two alpha-helices connected by a beta-turn. Insect larvae were paralyzed by injection of either of the purified toxins, with the recombinant one acting faster. The recombinant toxin-producing baculovirus reduced the average survival time of the insect host by 25 h compared with unmodified virus. Mass spectrometry analysis showed that the recombinant toxin has an N-terminal 21-residue extension, possibly improving its stability and/or stabilizing the membrane-bound state. The potential use of poneratoxin for the construction of biological insecticide is discussed.

Heparan sulfate proteoglycan mediates the selective attachment and internalization of serotype 3 human adenovirus dodecahedron

During adenovirus type 3 (Ad3) infection cycle, the penton (Pt) of the viral capsid, a noncovalent complex of fiber and penton base proteins, is produced in large excess and self-assembles to form a highly organized dodecahedral structure, termed dodecahedron (Dd). The physiological role of these particles is poorly understood, but we have recently reported that they can penetrate cells with high efficiency and thus may constitute an attractive tool for gene or protein delivery approaches. Surprisingly, Dd displayed the ability to enter cells non-permissive to Ad3, suggesting the existence of additional internalization modes. In this study, we show that Ad3 Dd binds to cell surface heparan sulfate (HS) through high affinity interaction with the penton base. Furthermore, binding to HS was found to be the prerequisite for a novel and Dd specific entry pathway that could not be used by Ad3. Overall, these data provide new insights in the possible role of Dd during viral infection and potential therapeutic applications.

Adenovirus dodecahedron allows large multimeric protein transduction in human cells

Adenovirus dodecahedron is a virus-like particle composed of only two viral proteins of human adenovirus serotype 3 that are responsible for virus attachment and internalization. We show here that this dodecameric particle, devoid of genetic information, efficiently penetrates human cells and can deliver large multimeric proteins such as immunoglobulins.

Controlled transgene expression by E1-E4-defective adenovirus vectors harbouring a "tet-on" switch system

BACKGROUND

The "tet switch system" was originally described under the tet-off configuration with its components encoded by two separate plasmids. Since then, many virus vectors harbouring tet-off components have been designed and their regulation by tetracycline is widely reported. On the contrary, tet-on regulation by viral vectors is poorly documented.

METHODS

E1-E4-defective adenoviruses harbouring either rtTA or the luciferase gene under a minimal inducible promoter (TK* or CMV*) or both components in a single genome were produced. Using either a double or a single virus strategy, induction of luciferase expression was investigated in various cell lines, in mice muscle and in rat brain.

RESULTS

Over 400-fold induction can be reached with PC12 and NHA cells using a double virus strategy. Comparison of the background activity of different minimal inducible promoters revealed a significant difference between TK* and CMV* promoters both with the cell culture and the in vivo experiments. Interestingly, a single virus strategy permitted an induction exceeding 600-fold with human astrocyte primary cells. Moreover, the E1-E4-defective adenovirus-mediated tet-on system can be quickly switched off and turned back on again. Depending on the cell line, the level of rtTA derived by the single virus strategy differed, resulting in different efficiencies. Experiments performed in rat striatum and mouse muscle confirmed the importance of rtTA expression and minimal promoter used on both doxycycline-independent expression and induction efficiency. Under appropriated rtTA expression, a 32-fold induction is observed in mouse muscle.

CONCLUSIONS

In the recombinant adenovirus context, the CMV* but not the TK* promoter is sensitive to transcriptional interference resulting in high doxycycline-independent expression. By paying attention to the rtTA expression, moderate and high induction can be obtained in vivo and in vitro accordingly.

[Management of severe hypertension in France in 1999 and 2000: intermediate results of a health insurance intervention program]

AIM

Within the framework of its long-term public health program aimed at improving the clinical management of hypertension (HBP), the French health care funds performed two nationwide surveys concerning affiliates who were recently waived from making co-payments for severe hypertension. The aim was to measure the difference between observed clinical management and benchmark care, defined by the 1997 ANAES guidelines (National Agency for Accreditation and Health Evaluation), at the onset (May 1999) and during the program (November 1999) in order to detect any changes in clinical management between the two study periods, the timeframe corresponding to the intervention period.

METHODS

The patient samples used in the two studies involved affiliates aged between 20 and 80 years old living in France or one of its overseas territories who were recently waived from making co-payments (ETM) for severe hypertension (these patients are reimbursed 100% for all care related to the disorder). The evaluation was based on retrospective data furnished by attending physicians. The indicators isolated in order to compare the two study periods were blood pressure control, suggested life-style changes and prescribed drugs.

RESULTS

The first survey took place between May and November 1999 and enrolled 10,665 patients (corresponding to a weighted patient population of 50,383) while the second studied 2,649 patients in November 2000. The study population in 1999 was, on the average, younger than the study population in November 2000: 63.1 years +/- 0.2 vs 65.4 years +/- 0.4. Nearly two patients out of three presented at least one other major cardiovascular risk factor in addition to HBP (cigarette smoking, diabetes mellitus or dyslipidemia): 63.9% in 1999 and 64.4% in 2000. Nearly one patient out of seven had associated coronary artery disease: 14.1% in 1999 and 15.3% in 2000 and more than one out of ten had associated cerebro-vascular disease: 12.7% in 1999 and 12.2% in 2000. There were more diabetic patients in the 1999 group than in the 2000 group: 27.5% +/- 1.0 vs 23.9% +/- 1.6. The proportion of patients who had poorly controlled blood pressure (systolic > 140 mmHg or > 160 mmHg in subjects aged between 60 and 80 years with isolated systolic hypertension, or a diastolic > 90 mmHg) did not change: 46.8% +/- 1.1 in 1999 and 45.7% +/- 1.9 in 2000. If the guideline recommendations for diabetics (blood pressure < 130/85) are applied. 85.4% of the diabetic patients were poorly controlled in 1999 and 86.6% in 2000. Similarly, in hypertensive patients with kidney failure (guideline recommendations: < 125/75 mmHg), 94.5% were poorly controlled in 1999 and 96.3% in 2000. Recommended life-style changes (reduction in salt intake, weight loss, lower alcohol consumption, increased physical activity) were not well followed in both studies: in 1999, fewer than one patient out of four completely implemented the desired changes (23.7%) while only 24.5% did so in 2000. Physicians prescribed specifically indicated therapeutic agents considering associated diseases in 68.0% of the patients in 1999 and in 67.6% in 2000. Prescriptions contained a potentially contraindicated drug in 27.3% of the cases in 1999 and in 28.0% in 2000.

CONCLUSION

A comparison of the results of the two surveys performed in 1999 and 2000 concerning the management of patients with severe hypertension failed to demonstrate any significant differences in blood pressure control or treatment modalities. While not questioning the value of the interventions of the health funds, these findings illustrate how difficult it is to change clinical practice over a short time period, especially in a disorder involving a number of different elements which include, among others, individual patient behavior. In order to significantly improve clinical management, it will probably be necessary to continue the dialogue between medical advisors of the health care funds (médecins conseils) and clinicians and to renew campaigns aimed at helping patients become more responsible.

[Treatment of severe arterial hypertension: cost of drug prescriptions in accordance with ANAES guidelines]

French national health insurance has carried out two nationwide surveys as part of its programme intended to improve the care given to patients with hypertension, focusing on affiliates diagnosed with severe hypertension entitled to exemption from co-payments (patients are reimbursed 100 per cent for all care related to the corresponding disorder). The objective was to measure the difference between observed care and the quality of care delineated in the guidelines (1997) elaborated by the National Agency for Healthcare Accreditation and Evaluation (ANAES). The before and after comparison was designed to determine whether actual care is in accordance with the guideline's standards. The initial survey took place from 31 May to 12 November 1999 over the entire French territory (metropolitan and overseas departments) and concerned a representative sample of patients whose ages ranged from 20 to 80 years at the time they qualified for exemption from co-payments for severe hypertension. The method used for comparison involved the calculation of a number of different evaluation parameters, the principal one being blood pressure control, using the systolic (PAS) and diastolic (PAD) pressures reported by attending physicians. Other evaluation parameters included the quality of the therapeutic strategy utilized. A total of 10,665 patients were enrolled in the survey by using information gathered from 8377 practicing physicians. Extrapolated to the entire population in 1999, the results can be applied to 50,383 patients. The average age was 63 years and the patients had been treated for hypertension for an average of 9 years. In addition to severe hypertension, 64 per cent of the patients had other significant high-risk factors for cardiovascular disease: 44 per cent had dyslipidemia, 28 per cent had diabetes mellitus, 15 per cent were smokers. In 41 per cent of cases, the patients' blood pressures were well controlled (systolic and diastolic pressures below 140/90 mmHg or, for patients older than 60 years with only isolated systolic hypertension, systolic pressure equal to or lower than 160 mmHg); in 12 per cent of cases the patients' blood pressures were equal to the limit values; in 47 per cent of cases blood pressure was poorly controlled. Diabetics had poorly controlled blood pressure in 85 per cent of cases (systolic or diastolic pressures greater than 130/85 mmHg) and, similarly, 94 per cent of the patients who were in renal failure were poorly controlled (systolic or diastolic pressures greater than 125/75 mmHg). Preferential prescription with a particular therapeutic class, because of an existing comorbidity, was found in 68 per cent of patients whereas potentially contraindicated therapeutic classes were prescribed in 27 per cent. The daily cost of anti-hypertensive drug therapy was estimated at 8.05 francs per day per patient. Extrapolated to the study population in 1999, this represents 148.1 million francs. Less than 1 per cent of this observed cost (1.1 million francs) was economized by prescribing less expensive, alternative drug specialties in spite of the fact that an estimated 9.6 million francs could have been saved if these equivalent, alternative drugs had been prescribed. The potential saving corresponds to 6.5 per cent of the total observed cost. The care given to severely hypertensive patients is sub-optimum when compared with the ANAES guidelines (1997). In public health terms, the most preoccupying feature is poor blood pressure control because it occurs in a patient population with a high cardiovascular risk. These findings fully justify the continuation and amplification of the actions undertaken in this nationwide public health programme concerning the medical care given to hypertensive patients.

[Totally reimbursed care for type 2 diabetes in 1994: characteristics and follow-up]

Non-insulin-dependent diabetes mellitus (NIDDM) is an important health issue in France. According to projections from current data, the problem should increase over the upcoming years. The aim of this study was to determine the characteristics of patients with NIDDM who are enrolled on the list of 30 long term diseases (ALD30) and examine their follow-up and disease-related complications. This study was performed with the data base established by the French National Health Insurance for Salaried Workers (CMANTS) in 1994. Diagnosis and medical information were coded by official physicians, who either examined the patients or consulted their primary care physician (69% of the cases), or relied on available medical records. Eight thousand two hundred forty-seven patients (sex ration=0.95) with NIDDM enrolled on the long term disease list were included. Mean age was 65.1+/- 0.13 years (m+/- SEM). More than one blood glucose level per year was available for 89% of the patients and an HA1c assay in only 34%. In addition, for patient follow-up at least once a year, 80%, 47%, and 42% of the patients had a serum creatinine assay, a funus examination, or an electorcariogram respectively. Irrespective of the criteria retained (fasting glucose=1.26 g/l; fasting glucose=1.40 g/l) there was a high percentage of patients whose level was well above the limit (75% and 63% respectively). For HbA1c, only a quarter of the patients had values lower than the limits defined by the ANAES and AFFSAPS guidelines. The percentage of diabetic patients without complications was 41% (hypertension excluded). The most frequently observed complications isolated peripheral vascular conditions (31%). These results were obtained from a database created in 1994, before guidelines on type 2 diabetes were officially published. They can serve as a reference to follow medical practices.

[Epidemiology of diabetes in metropolitan France]

The statistical analysis of French HealthCare's database, containing total reimbursements to affiliates and a listing of delivered drug prescriptions in the form of specific drug codes, allowed us to update data on the epidemiology of diabetes. This study, performed during the first trimester of 1999 on the entire population of metropolitan France, found an overall prevalence of 2.78 % for diabetes in all affiliates of the regimen (Régime général) stricto sensu (3.06 % in the general population), 0.41 % corresponding to diabetic treated exclusively with insulin (0.44 % in the overall population) and to 0.12 % receiving both insulin and oral hypoglycemic agents concomitantly (0.13 % in the general population). The average age of diabetics, irrespective of the treatment they were receiving, was 63.1 years with a sex ratio M/F of 1.04. These findings confirm epidemiological forecasts which had predicted a significant increase in the prevalence of diabetes over the past few years. The study also confirmed data from the medical literature concerning geographic disparities in the epidemiology of this disease except for the results obtained in the north of France, a region generally thought to have a lower prevalence of diabetes, and which was found to have a prevalence equal to even greater than the national average.

[Modalities of follow-up on non-insulin treated diabetics treated in metropolitan France in 1998]

The statistical analysis of French HealthCare's database allows a retrospective evaluation of the overall clinical care given to diabetics in the light of the guidelines (RBPC) promulgated by the National Agency of Health Accreditation and Evaluation (ANAES). This database contains no information on the stage of the disease process, the completeness of the clinical evaluation (neurological or foot examination) or the results of significant blood tests. We studied the follow-up care given to diabetics whom we were able to identify by isolating reimbursements for hypoglycemic agents using their corresponding drug codes. Considering the time needed for this new drug-coding system to become fully operational, the results can be extrapolated to the entire population of non-insulin treated diabetics. In 1998, almost all follow-up care was provided by general practitioners since only 5.5 % of the patients consulted an endocrinologist during the year studied. Blood sugar was generally monitored with fasting blood sugars rather than HbA1c which was only prescribed in 41.3 % of the patients during the final six months of the period under consideration. Screening and follow-up for degenerative complications were insufficient. Fewer than 40 % of the patients had received reimbursement for an ophtalmological consultation during the preceeding year and fewer than 30 % had an ambulatory resting EKG over the same time period. A certain number of factors were studied in order to determine if they were correlated to better clinical follow-up. The best follow-up was encountered in patients who had a consultation with an endocrinologist at least once during the year, those who were exonerated from co-payments (ALD 30) and finally, those aged between 40 and 59 years (at least with respect to appropriate laboratory tests).

[Analysis of health insurance benefits: material and methods]

The statistical analysis of national health insurance's database, containing a record of the care reimbursed to affiliated members and delivered drugs in the form of special pharmacy codes, enable us to evaluate the follow-up care given to diabetics, to update epidemiological information and to determine the actual cost of diabetes. The method used consisted in the identification of diabetics by isolating patients who received hypoglycemic agents during the 3-month inclusion period followed by a retrospective determination of total reimbursements made through the 128 local health offices (CPAM) located in metropolitan France in order to study the reimbursed care (medical consultations, procedures and drug prescriptions) given to diabetics over the preceding 12 month period. Considering that the pharmacy coding system was still incomplete at the time the study was undertaken, we had to verify that the population selected by the coding system was only partially operational, requiring a calculation involving weighted coefficients. Finally, we needed to take into account the fact that the resulting data contained virtually no information on facilities receiving a once a year total budget allocation (all public hospital).