Changes in the incidence and management of spinal tuberculosis in a French University Hospital Rheumatology Department from 1966 to 2010

IntroductionTwo previous single-center studies in a university hospital rheumatology department suggested an increase in the incidence of spinal tuberculosis in France in the 1990s. Our objective in this study was to obtain incidence data on spinal tuberculosis since 1995 in the same department and to describe changes over the entire study period from 1966 to 2010. We also compared patients seen between 1966 and 1995 to those seen between 1995 and 2010.MethodsWe conducted a retrospective review of all cases of spinal tuberculosis seen in our rheumatology department between 1966 and June 1995 and between July 1995 and 2010. We collected the annual incidence, clinical and radiological features, and diagnostic and therapeutic strategies.ResultsOne hundred and thirty patients were managed between 1966 and 2010. The number of cases declined in the 1970s and 1980s then increased over the next two decades. None of the patients had HIV infection. Over 70% of patients were from continental France. Compared to patients seen during the earlier period, those seen after June 1995 were older (62.8 ± 17.2 vs. 53 ± 14.3 years, P = 0.0006), had more comorbidities, and more often exhibited severe radiological findings (including multilevel involvement, epidural involvement, and abscesses). No changes occurred in time to diagnosis or management strategies.ConclusionThe incidence of spinal tuberculosis in a university hospital rheumatology department has increased over the last two decades, chiefly as a result of reactivation of past tuberculosis, as opposed to origin from endemic countries or HIV infection.     

Use of a Human-Like Low-Grade Bacteremia Model of Experimental Endocarditis To Study the Role of Staphylococcus aureus Adhesins and Platelet Aggregation in Early Endocarditis

Animal models of infective endocarditis (IE) induced by high-grade bacteremia revealed the pathogenic roles of Staphylococcus aureus surface adhesins and platelet aggregation in the infection process. In humans, however, S. aureus IE possibly occurs through repeated bouts of low-grade bacteremia from a colonized site or intravenous device. Here we used a rat model of IE induced by continuous low-grade bacteremia to explore further the contributions of S. aureus virulence factors to the initiation of IE. Rats with aortic vegetations were inoculated by continuous intravenous infusion (0.0017 ml/min over 10 h) with 10⁶ CFU of Lactococcus lactis pIL253 or a recombinant L. lactis strain expressing an individual S. aureus surface protein (ClfA, FnbpA, BCD, or SdrE) conferring a particular adhesive or platelet aggregation property. Vegetation infection was assessed 24 h later. Plasma was collected at 0, 2, and 6 h postinoculation to quantify the expression of tumor necrosis factor (TNF), interleukin 1α (IL-1α), IL-1β, IL-6, and IL-10. The percentage of vegetation infection relative to that with strain pIL253 (11%) increased when binding to fibrinogen was conferred on L. lactis (ClfA strain) (52%; P = 0.007) and increased further with adhesion to fibronectin (FnbpA strain) (75%; P < 0.001). Expression of fibronectin binding alone was not sufficient to induce IE (BCD strain) (10% of infection). Platelet aggregation increased the risk of vegetation infection (SdrE strain) (30%). Conferring adhesion to fibrinogen and fibronectin favored IL-1β and IL-6 production. Our results, with a model of IE induced by low-grade bacteremia, resembling human disease, extend the essential role of fibrinogen binding in the initiation of S. aureus IE. Triggering of platelet aggregation or an inflammatory response may contribute to or promote the development of IE.     

Carbamazepine augmentation in depressive patients non-responding to citalopram: a pharmacokinetic and clinical pilot study.

Citalopram is a chiral antidepressant drug. Its eutomer, S-citalopram (escitalopram), has recently been introduced as an antidepressant. In an open pilot study, four outpatients and two inpatients with a major depressive episode (ICD-10), and who were nonresponders to a 4-week pretreatment with 40-60 mg/day citalopram, were comedicated for another 4-week period with carbamazepine (200-400 mg/day). Some of the patients suffered also from comorbidities: Phobic anxiety disorder with panic attacks (n=2), generalised anxiety disorder, alcohol abuse, dependent personality disorder, hypertension (n=1). After a 4-week augmentation therapy with carbamazepine, a significant (P<0.03) decrease of the plasma concentrations of S-citalopram and R-citalopram, by 27 and 31%, respectively, was observed. Apparently, the probable induction of CYP3A4 by carbamazepine results in a nonstereoselective increase in N-demethylation of citalopram. Moreover, there was a significant (P<0.03) decrease of the ratio S/R-citalopram propionic acid derivative, the formation of it being partly regulated by MAO-A and MAO-B. Already, within 1 week after addition of carbamazepine, there was a slight but significant (P<0.03) decrease of the MADRS depression scores, from 27.0+/-7.7 (mean+/-S.D.) to 23.3+/-6.6, and the final score on day 56 was 18.8+/-10.9. The treatment was generally well tolerated. There was no evidence of occurrence of a serotonin syndrome. After augmentation with carbamazepine, treatment related adverse events were: Nausea in one case, diarrhea in one case, and rash in two cases. In conclusion, the results of this pilot study suggest that carbamazepine augmentation of a citalopram treatment in previous nonresponders to citalopram may be clinically useful, but that in addition carbamazepine can lead to a decrease of the plasma concentrations of the active enantiomer escitalopram.     

Ecological Temporal Stability of Staphylococcus aureus Nasal Carriage

We described the colonization dynamics of Staphylococcus aureus in a group of 266 healthy carriers over a period of approximately 1 year. We used precise genotyping methods, i.e., amplified fragment length polymorphism (AFLP), spa typing, and double-locus sequence typing (DLST), to detect changes in strain identity. Strain change took place rather rarely: out of 89 carriers who had initially been colonized, only 7 acquired a strain different from the original one. Approximately one-third of the carriers eliminated the colonization, and a similar number became newly colonized. Some of these events probably represent detection failure rather than genuine colonization loss or acquisition. Lower bacterial counts were associated with increased probability of eliminating the colonization. We have confirmed a high mutation rate in the spa locus: 6 out of 53 strains underwent mutation in the spa locus. There was no overall change in S. aureus genotype composition.Staphylococcus aureus is an important human pathogen responsible for both nosocomial and community-acquired infections, but it also asymptomatically colonizes a large fraction of humans (20 to 60%). Although most carriers never experience health problems related to colonization, it is estimated that 80% of infections with S. aureus are endogenous, i.e., caused by the colonizing strain (19, 20). Understanding of the interplay between nasal carriage and infection with S. aureus is far from complete. For example, it is not known whether prior nasal carriage of S. aureus (methicillin-susceptible S. aureus [MSSA]) might prevent hospital-acquired colonization and subsequent infection with methicillin-resistant S. aureus (MRSA).Particularly little is known about persistence and transmission. Many studies have described temporal patterns of carriage, but only a handful explicitly monitored the temporal changes in strain identity (17, 18). Persistence and transmissibility should be the main determinants of long-term fitness of S. aureus. Low transmission of S. aureus in comparison with other staphylococcal human colonizers such as S. epidermidis has been suggested to play a major role in its evolutionary increase in virulence (9). Moreover, the differences in transmissibility can have implications for human health care. For example, MRSA with superb transmission abilities might be much more problematic than virulent MRSA with low transmission.Explicit studies of transmission of S. aureus are difficult for logistic reasons, but those which have been carried out have brought interesting insights. For example, Peacock et al. (11) have found that for healthy newborn babies the primary source of S. aureus is the mother. Documenting the persistence of a bacterial strain in a human host requires longitudinal sampling and precise genotyping of bacterial strains.Here we have documented the colonization dynamics of healthy adult carriers with S. aureus strains. We have also explored host and bacterial characteristics responsible for differences in persistence. In addition, we have monitored microevolutionary changes in the spa and clfB genes, which are used for genotyping.     

Histone deacetylase inhibitors impair antibacterial defenses of macrophages

Histone deacetylases (HDACs) control gene expression by deacetylating histones and nonhistone proteins. HDAC inhibitors (HDACi) are powerful anticancer drugs that exert anti-inflammatory and immunomodulatory activities. We recently reported a proof-of-concept study demonstrating that HDACi increase susceptibility to bacterial infections in vivo. Yet, still little is known about the effects of HDACi on antimicrobial innate immune defenses. Here we show that HDACi belonging to different chemical classes inhibit at multiple levels the response of macrophages to bacterial infection. HDACi reduce the phagocytosis and the killing of Escherichia coli and Staphylococcus aureus by macrophages. In line with these findings, HDACi decrease the expression of phagocytic receptors and inhibit bacteria-induced production of reactive oxygen and nitrogen species by macrophages. Consistently, HDACi impair the expression of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase subunits and inducible nitric oxide synthase. These data indicate that HDACi have a strong impact on critical antimicrobial defense mechanisms in macrophages.     

Astrocytes induce several blood-brain barrier properties in non-neural endothelial cells.

The passage of immunocompetent cells across the blood-brain barrier (BBB) is regulated at the level of the cerebral capillaries which have specific morphological and biochemical properties. We have developed and characterized an in vitro model of the BBB using immortalized human endothelial cells (ECV 304) induced by rat astrocytes. In this model, endothelial cells are attached together by continuous intercellular junctions with numerous tight junctions, develop a permeability barrier having a significant transcellular electrical resistance, possess high activities of gamma-glutamyl transpeptidase (gamma-GTP) and express the brain-type glucose transporter 1 (GLUT-1). These parameters are also characteristic of brain capillary endothelial cells. Under the culture conditions used, the ECV 304 cells express the intercellular adhesion molecule-1 (ICAM-1) on the external plasma membrane at concentrations which could permit lymphocyte adhesion to be studied.     

Induction of neutralising antibodies and cellular immune responses against SARS coronavirus by recombinant measles viruses

Live attenuated recombinant measles viruses (rMV) expressing a codon-optimised spike glycoprotein (S) or nucleocapsid protein (N) of severe acute respiratory syndrome-associated coronavirus (SARS-CoV) were generated (rMV-S and rMV-N). Both recombinant viruses stably expressed the corresponding SARS-CoV proteins, grew to similar end titres as the parental strain and induced high antibody titres against MV and the vectored SARS-CoV antigens (S and N) in transgenic mice susceptible to measles infection. The antibodies induced by rMV-S had a high neutralising effect on SARS-CoV as well as on MV. Moreover, significant N-specific cellular immune responses were measured by IFN-gamma ELISPOT assays. The pre-existence of anti-MV antibodies induced by the initial immunisation dose did not inhibit boost of anti-S and anti-N antibodies. Immunisations comprising a mixture of rMV-S and rMV-N induced immune responses similar in magnitude to that of vaccine components administered separately. These data support the suitability of MV as a bivalent candidate vaccine vector against MV and emerging viruses such as SARS-CoV.     

Small Molecule Kinase Inhibitors for LRRK2 and Their Application to Parkinson's Disease Models

Parkinson's disease (PD) is the second most common neurodegenerative disorder. Several single gene mutations have been linked to this disease. Mutations in the gene encoding leucine-rich repeat kinase 2 (LRRK2) indicate LRRK2 as promising therapeutic target for the treatment of PD. LRRK2 mutations were observed in sporadic as well as familial PD patients and have been investigated intensively. LRRK2 is a large and complex protein, with multiple enzymatic and protein-interaction domains, each of which is effected by mutations. The most common mutation in PD patients is G2019S. Several LRRK2 inhibitors have been reported already, although the crystal structure of LRRK2 has not yet been determined. This review provides a summary of known LRRK2 inhibitors and will discuss recent in vitro and in vivo results of these inhibitors.