A novel antibiotic class targeting the lipopolysaccharide transporter

Carbapenem-resistant Acinetobacter baumannii (CRAB) has emerged as a major global pathogen with limited treatment options1. No new antibiotic chemical class with activity against A. baumannii has reached patients in over 50 years1. Here we report the identification and optimization of tethered macrocyclic peptide (MCP) antibiotics with potent antibacterial activity against CRAB. The mechanism of action of this molecule class involves blocking the transport of bacterial lipopolysaccharide from the inner membrane to its destination on the outer membrane, through inhibition of the LptB2FGC complex. A clinical candidate derived from the MCP class, zosurabalpin (RG6006), effectively treats highly drug-resistant contemporary isolates of CRAB both in vitro and in mouse models of infection, overcoming existing antibiotic resistance mechanisms. This chemical class represents a promising treatment paradigm for patients with invasive infections due to CRAB, for whom current treatment options are inadequate, and additionally identifies LptB2FGC as a tractable target for antimicrobial drug development.

Small molecule AX-024 reduces T cell proliferation independently of CD3ϵ/Nck1 interaction, which is governed by a domain swap in the Nck1-SH3.1 domain

Activation of the T cell receptor (TCR) results in binding of the adapter protein Nck (noncatalytic region of tyrosine kinase) to the CD3ϵ subunit of the TCR. The interaction was suggested to be important for the amplification of TCR signals and is governed by a proline-rich sequence (PRS) in CD3ϵ that binds to the first Src homology 3 (SH3) domain of Nck (Nck-SH3.1). Inhibition of this protein/protein interaction ameliorated inflammatory symptoms in mouse models of multiple sclerosis, psoriasis, and asthma. A small molecule, AX-024, was reported to inhibit the Nck/CD3ϵ interaction by physically binding to the Nck1-SH3.1 domain, suggesting a route to develop an inhibitor of the Nck1/CD3ϵ interaction for modulating TCR activity in autoimmune and inflammatory diseases. We show here that AX-024 reduces T cell proliferation upon weak TCR stimulation but does not significantly affect phosphorylation of Zap70 (ζ chain of T cell receptor–associated protein kinase 70). We also find that AX-024 is likely not involved in modulating the Nck/TCR interaction but probably has other targets in T cells. An array of biophysical techniques did not detect a direct interaction between AX-024 and Nck-SH3.1 in vitro. Crystal structures of the Nck-SH3.1 domain revealed its binding mode to the PRS in CD3ϵ. The SH3 domain tends to generate homodimers through a domain swap. Domain swaps observed previously in other SH3 domains indicate a general propensity of this protein fold to exchange structural elements. The swapped form of Nck-SH3.1 is unable to bind CD3ϵ, possibly representing an inactive form of Nck in cells.

Dissecting charge relaxation pathways in CdSe/CdS nanocrystals using femtosecond two-dimensional electronic spectroscopy

Exciton relaxation dynamics of CdSe and quasi-type-II CdSe/CdS core/shell nanocrystals were examined using femtosecond two-dimensional electronic spectroscopy (2DES). The use of 2DES allowed for determination of structure-specific and state-resolved carrier dynamics for CdSe nanocrystals formed with five, or fewer, CdS passivation monolayers (ML). For CdSe and CdSe/CdS nanocrystals formed with one through three MLs of CdS, excitation using broad bandwidth femtosecond visible laser pulses generated electron-hole pairs among the |X₁〉 = 2.14 eV and |X₂〉 = 2.27 eV exciton states. For both excitations, the electron is promoted to the lowest energy excited (1S_e) conduction-band state and the hole is in the 1S_3/2 (X₁) or 2S_3/2 (X₂) valence-band state. Therefore, the relaxation dynamics of the hot hole were isolated by monitoring the-time-dependent amplitude of 2DES cross peaks. The time constant for hot hole relaxation within the CdSe valence band was 150 ± 45 fs. Upon passivation by CdS, this hole relaxation time constant increased to 170 ± 30 fs (CdSe/CdS-3ML). This small increase was attributed to the formation of a graded, or alloyed, interfacial region that precedes the growth of a uniform CdS capping layer. The small increase in hole relaxation time reflects the larger nanocrystal volume of the CdSe/CdS system with respect to the CdSe nanocrystal core. In contrast, the dynamics of larger core/shell nanocrystals (≥4ML CdS) exhibited a picosecond buildup in 2DES cross-peak amplitude. This time-dependent response was attributed to interfacial hole transfer from CdS to CdSe valence-band states. Importantly, the 2DES data distinguish CdSe exciton relaxation from interfacial carrier transfer dynamics. In combination, isolation of structurally well-defined nanocrystals and state-resolved 2DES can be used to examine directly the influence of nanoscale structural modifications on electronic carrier dynamics, which are critical for developing nanocluster-based photonic devices.

Clinical manifestations and coronary artery disease risk factors at diagnosis of systemic lupus erythematosus: data from an international inception cohort

Systemic Lupus International Collaborating Clinics (SLICC) comprises 27 centres from 11 countries. An inception cohort of 918 SLE patients has been assembled according to a standardized protocol between 2000 and 2006. Clinical features, classic coronary artery disease (CAD) risk factors, as well as other potential risk factors were collected. Of the 918 patients 89% were females, and of multi racial origin. Less than half the patients were living in a permanent relationship, 58% had post secondary education and 51% were employed. Eight percent had family history of SLE. At enrolment, with at mean age of diagnosis of 34.5 years, a significant number of patients already had CAD risk factors, such as hypertension (33%) and hypercholesterolemia (36%). Only 15% of the patients were postmenopausal, 16% were current smokers and 3.6% had diabetes at entry to the SLICC-RAS (Registry for Atherosclerosis). A number of patients in this multi-racial, multi-ethnic inception cohort of lupus patients have classic CAD risk factors within a mean of 5.4 months from diagnosis. This cohort will be increased to 1500 patients to be followed yearly for 10 years. This will provide a unique opportunity to evaluate risk factors for accelerated atherosclerosis in SLE. Lupus (2007) 16, 731—735.

Cardiovascular events prior to or early after diagnosis of systemic lupus erythematosus in the systemic lupus international collaborating clinics cohort

Objective

To describe the frequency of myocardial infarction (MI) prior to the diagnosis of systemic lupus erythematosus (SLE) and within the first 2 years of follow-up.

Methods

The systemic lupus international collaborating clinics (SLICC) atherosclerosis inception cohort enters patients within 15 months of SLE diagnosis. MIs were reported and attributed on a specialised vascular event form. MIs were confirmed by one or more of the following: abnormal ECG, typical or atypical symptoms with ECG abnormalities and elevated enzymes (≥2 times upper limit of normal), or abnormal stress test, echocardiogram, nuclear scan or angiogram. Descriptive statistics were used.

Results

31 of 1848 patients who entered the cohort had an MI. Of those, 23 patients had an MI prior to SLE diagnosis or within the first 2 years of disease. Of the 23 patients studied, 60.9% were female, 78.3% were Caucasian, 8.7% black, 8.7% Hispanic and 4.3% other. The mean age at SLE diagnosis was 52.5±15.0 years. Of the 23 MIs that occurred, 16 MIs occurred at a mean of 6.1±7.0 years prior to diagnosis and 7 occurred within the first 2 years of follow-up. Risk factors associated with early MI in univariate analysis are male sex, Caucasian, older age at diagnosis, hypertension, hypercholesterolaemia, family history of MI and smoking. In multivariate analysis only age (OR=1.06 95% CI 1.03 to 1.09), hypertension (OR=5.01, 95% CI 1.38 to 18.23), hypercholesterolaemia (OR=4.43, 95% CI 1.51 to 12.99) and smoking (OR=7.50, 95% CI 2.38 to 23.57) remained significant risk factors.

Conclusions

In some patients with lupus, MI may develop even before the diagnosis of SLE or shortly thereafter, suggesting that there may be a link between autoimmune inflammation and atherosclerosis.

Anti-C1q antibodies in systemic lupus erythematosus

OBJECTIVE

Anti-C1q has been associated with systemic lupus erythematosus (SLE) and lupus nephritis in previous studies. We studied anti-C1q specificity for SLE (vs rheumatic disease controls) and the association with SLE manifestations in an international multicenter study.

METHODS

Information and blood samples were obtained in a cross-sectional study from patients with SLE (n = 308) and other rheumatologic diseases (n = 389) from 25 clinical sites (84% female, 68% Caucasian, 17% African descent, 8% Asian, 7% other). IgG anti-C1q against the collagen-like region was measured by ELISA.

RESULTS

Prevalence of anti-C1q was 28% (86/308) in patients with SLE and 13% (49/389) in controls (OR = 2.7, 95% CI: 1.8-4, p < 0.001). Anti-C1q was associated with proteinuria (OR = 3.0, 95% CI: 1.7-5.1, p < 0.001), red cell casts (OR = 2.6, 95% CI: 1.2-5.4, p = 0.015), anti-dsDNA (OR = 3.4, 95% CI: 1.9-6.1, p < 0.001) and anti-Smith (OR = 2.8, 95% CI: 1.5-5.0, p = 0.01). Anti-C1q was independently associated with renal involvement after adjustment for demographics, ANA, anti-dsDNA and low complement (OR = 2.3, 95% CI: 1.3-4.2, p < 0.01). Simultaneously positive anti-C1q, anti-dsDNA and low complement was strongly associated with renal involvement (OR = 14.9, 95% CI: 5.8-38.4, p < 0.01).

CONCLUSIONS

Anti-C1q was more common in patients with SLE and those of Asian race/ethnicity. We confirmed a significant association of anti-C1q with renal involvement, independent of demographics and other serologies. Anti-C1q in combination with anti-dsDNA and low complement was the strongest serological association with renal involvement. These data support the usefulness of anti-C1q in SLE, especially in lupus nephritis.

Current state of evidence on 'off-label' therapeutic options for systemic lupus erythematosus, including biological immunosuppressive agents, in Germany, Austria and Switzerland--a consensus report

Systemic lupus erythematosus (SLE) can be a severe and potentially life-threatening disease that often represents a therapeutic challenge because of its heterogeneous organ manifestations. Only glucocorticoids, chloroquine and hydroxychloroquine, azathioprine, cyclophosphamide and very recently belimumab have been approved for SLE therapy in Germany, Austria and Switzerland. Dependence on glucocorticoids and resistance to the approved therapeutic agents, as well as substantial toxicity, are frequent. Therefore, treatment considerations will include 'off-label' use of medication approved for other indications. In this consensus approach, an effort has been undertaken to delineate the limits of the current evidence on therapeutic options for SLE organ disease, and to agree on common practice. This has been based on the best available evidence obtained by a rigorous literature review and the authors' own experience with available drugs derived under very similar health care conditions. Preparation of this consensus document included an initial meeting to agree upon the core agenda, a systematic literature review with subsequent formulation of a consensus and determination of the evidence level followed by collecting the level of agreement from the panel members. In addition to overarching principles, the panel have focused on the treatment of major SLE organ manifestations (lupus nephritis, arthritis, lung disease, neuropsychiatric and haematological manifestations, antiphospholipid syndrome and serositis). This consensus report is intended to support clinicians involved in the care of patients with difficult courses of SLE not responding to standard therapies by providing up-to-date information on the best available evidence.

Autoantibodies in systemic lupus erythematosus: comparison of historical and current assessment of seropositivity

Systemic lupus erythematosus (SLE) is characterized by multiple autoantibodies and complement activation. Recent studies have suggested that anti-nuclear antibody (ANA) positivity may disappear over time in some SLE patients. Anti-double-stranded DNA (dsDNA) antibody titers and complement levels may vary with time and immunosuppressive treatment, while the behavior of anti-extractable nuclear antigen (ENA) over time is less well understood. This study sought to determine the correlation between historical autoantibody tests and current testing in patients with SLE. Three hundred and two SLE patients from the ACR Reclassification of SLE (AROSE) database with both historical and current laboratory data were selected for analysis. The historical laboratory data were compared with the current autoantibody tests done at the reference laboratory and tested for agreement using percent agreement and Kappa statistic. Serologic tests included ANA, anti-dsDNA, anti-Smith, anti-ribonucleoprotein (RNP), anti-Ro, anti-La, rheumatoid factor (RF), C3 and C4. Among those historically negative for immunologic markers, a current assessment of the markers by the reference laboratory generally yielded a low percentage of additional positives (3-13%). However, 6/11 (55%) of those historically negative for ANA were positive by the reference laboratory, and the reference laboratory test also identified 20% more patients with anti-RNP and 18% more with RF. Among those historically positive for immunologic markers, the reference laboratory results were generally positive on the same laboratory test (range 57% to 97%). However, among those with a history of low C3 or C4, the current reference laboratory results indicated low C3 or C4 a low percentage of the time (18% and 39%, respectively). ANA positivity remained positive over time, in contrast to previous studies. Anti-Ro, La, RNP, Smith and anti-dsDNA antibodies had substantial agreement over time, while complement had less agreement. This variation could partially be explained by variability of the historical assays, which were done by local laboratories over varying periods of time. Variation in the results for complement, however, is more likely to be explained by response to treatment. These findings deserve consideration in the context of diagnosis and enrolment in clinical trials.

Platelet-released supernatant induces osteoblastic differentiation of human mesenchymal stem cells: potential role of BMP-2

Platelet-rich preparations have recently gained popularity in maxillofacial and dental surgery, but their beneficial effect is still under debate. Furthermore, very little is known about the effect of platelet preparations at the cellular level, and the underlying mechanisms. In this study, we tested the effect of platelet-released supernatant (PRS) on human mesenchymal stem cell (MSC) differentiation towards an osteoblastic phenotype in vitro. Cultures of MSC were supplemented with PRS and typical osteoblastic markers were assessed at up to 28 days post-confluence. PRS showed an osteoinductive effect on MSC, as shown by an increased expression of typical osteoblastic marker genes such as collagen Ialpha1, bone sialoprotein II, BMP-2 and MMP-13, as well as by increased ⁴⁵Ca²+ incorporation. Our results suggest that the effect of PRS on human MSC could be at least partially mediated by BMP-2. Activated autologous PRS could therefore provide an alternative to agents like recombinant bone growth factors by increasing osteoblastic differentiation of bone precursor cells at bone repair sites, although further studies are needed to fully support our observations.

Atherosclerotic vascular events in a multinational inception cohort of systemic lupus erythematosus

OBJECTIVE

To describe vascular events during an 8-year followup in a multicenter systemic lupus erythematosus (SLE) inception cohort and their attribution to atherosclerosis.

METHODS

Clinical data, including comorbidities, were recorded yearly. Vascular events were recorded and attributed to atherosclerosis or not. All of the events met standard clinical criteria. Factors associated with atherosclerotic vascular events were analyzed using descriptive statistics, t-tests, and chi-square tests. Stepwise multivariate logistic regression was used to assess the association of factors with vascular events attributed to atherosclerosis.

RESULTS

Since 2000, 1,249 patients have been entered into the cohort. There have been 97 vascular events in 72 patients, including: myocardial infarction (n = 13), angina (n = 15), congestive heart failure (n = 24), peripheral vascular disease (n = 8), transient ischemic attack (n = 13), stroke (n = 23), and pacemaker insertion (n = 1). Fifty of the events were attributed to active lupus, 31 events in 22 patients were attributed to atherosclerosis, and 16 events were attributed to other causes. The mean +/- SD time from diagnosis to the first atherosclerotic event was 2.0 +/- 1.5 years. Compared with patients followed for 2 years without atherosclerotic events (n = 615), at enrollment, patients with atherosclerotic vascular events were more frequently white, men, older at diagnosis of SLE, obese, smokers, hypertensive, and had a family history of coronary artery disease. On multivariate analysis, only male sex and older age at diagnosis were associated factors.

CONCLUSION

In an inception cohort with SLE followed for up to 8 years, there were 97 vascular events, but only 31 were attributable to atherosclerosis. Patients with atherosclerotic events were more likely to be men and to be older at diagnosis of SLE.

[Are there associations of health status, disease activity and damage in SLE patients?---Results of a study of a cohort of a Swiss specialized outpatient clinic]

AIM

To study the relationship between self assessed health status of patients with Systemic Lupus Erythematosus (SLE), lupus activity, damage, patients' age and disease duration in a cohort of a Swiss specialized outpatient clinic.

PATIENTS AND METHODS

A cross sectional study of 38 patients fulfilling the classification criteria for SLE. The patients visited a rheumatology outpatient clinic in Switzerland between January 2002 and December 2004. The last assessment during this period was used for the study. The assessment included, besides demographic data, the measurement of disease activity using the BILAG index, the measurement of disease damage using the SLICC/ACR damage index (SDI), as well as the patient's self assessed health status using the patient's questionnaire Medical Outcome Survey Short Form 36 (SF-36).

RESULTS

A total of 36 women and 2 men were included in the study (median age: 43 yrs, median disease duration: 11 yrs). Increased disease activity (total BILAG) was shown to be significantly correlated with reduced physical function. A greater damage (total SDI) correlated significantly with reduced role function due to emotional limitations. Neither age nor disease duration showed any significant correlation with health status in this study.

CONCLUSION

The present study, which is based on internationally accepted assessment tools for SLE patients, shows a significant relationship between increased disease activity and reduced physical function. This result emphasizes the importance of optimizing treatment aiming at reducing disease activity.

[Back pain and acne conglobata: SAPHO syndrome]

We report on a young woman suffering from SAPHO syndrome with back pain and arthritis of the sternoclavicular joints. This inflammatory disorder of the osteoarticular system (synovitis, osteitis, and hyperostosis) is associated with severe acne or palmoplantar pustulosis. The patient was treated with pamidronate, NSAID and physiotherapy which improved the musculoskeletal symptoms completely. The acne was treated with isotretinoin.

[The role of PCR for the diagnosis of Lyme arthritis]

OBJECTIVE, PATIENTS AND METHODS

We studied retrospectively four patients with Lyme arthritis of the knee, the role of PCR for the detection of B. burgdorferi DNA and its influence on further therapeutic decisions.

RESULTS

All four patients with Lyme arthritis suffered from knee pain and effusions. None of them remembered having had a tick bite or an erythema migrans. The diagnosis was confirmed by positive serology and in three cases by detection of B. burgdorferi DNA by PCR analysis of the joint fluid. In one patient, PCR was also positive in the synovial tissue. Because of persistent symptoms after adequate antibiotic therapy, PCR was repeated in the joint fluid of two patients. In one patient a positive PCR suggested an ongoing infection. Thus, the antibiotic treatment was changed. A further PCR was negative. Symptoms resolved slowly in all patients over a time of two to seven months after the end of the antibiotic treatment.

CONCLUSION

PCR to detect B. burgdorferi DNA in synovial fluid or tissue respectively is a helpful tool for the diagnosis of Lyme arthritis. Moreover, in patients with refractory Lyme arthritis PCR may be helpful in monitoring the course of the disease.

Analysis of the relationship between disease activity and damage in patients with systemic lupus erythematosus--a 5-yr prospective study

OBJECTIVE

To determine whether initial damage, disease duration, age, initial health status, average disease activity over the 5 yr or an average medication score covering the follow-up period would predict an increase in damage in patients with systemic lupus erythematosus (SLE) within the next 5 yr.

METHODS

A 5-yr prospective longitudinal study of a cohort of 141 consecutive patients with SLE attending a specialist lupus out-patient clinic in London from their first assessment between July 1994 and February 1995. Disease activity was assessed using the BILAG system, initial health status by the Medical Outcome Survey Short Form 20 with an extra question about fatigue (SF-20+) and damage by the SLICC/ACR Damage Index (SDI). Damage was reassessed 5 yr later. Statistical analysis was carried out using multiple logistic regression analysis (logXact).

RESULTS

One hundred and thirty-three female and eight male SLE patients (97 Caucasians, 16 Afro-Caribbeans, 22 Asians and 6 others) were included, their age at inclusion was 41.1 +/- 12.5 yr and their disease duration 10.2 +/- 6.3 yr. The mean measures at inclusion were: total BILAG 5.2 (range 0-17), total SDI 1.2 (0-7) and medication score 1.2 (0-3). Six patients were lost to follow-up because they had moved. Of the remaining 135 patients total damage had increased in 40 patients and 10 patients had died. At the end of the study, at 4.63 +/- 0.19 yr, the total SDI had increased to 1.6 +/- 1.7. Multiple logistic regression analysis revealed that death and increase in damage were strongly predicted by a high total disease activity over the entire study period (P<0.001) as we had hypothesized. When the total BILAG score was replaced by the average number of A-flares the prediction of accrual of damage during the study period was again highly significant (P = 0.004).

CONCLUSIONS

In this first prospective study of its type a highly significant impact of total disease activity, as measured over 5 yr using the BILAG system, on the development of total damage was revealed. Moreover, these results provide further proof of the validity of the SDI and support the BILAG concept of the A-flares.

Cross-section measurements of the nuclear reactions natZn(d,x)64Cu, 66Zn(d,alpha)64Cu and 68Zn(p,alphan)64Cu for production of 64Cu and technical developments for small-scale production of 67Cu via the 70Zn(p,alpha)67Cu process

The radionuclides 64Cu (T1/2=12.7h) and 67Cu (T1/2=61.9h) are useful in internal therapy. In connection with production of 64Cu, excitation functions of the reactions natZn(d,x)64Cu, 66Zn(d,alpha)64Cu and 68Zn(p,alphan)64Cu were measured radiochemically using the stacked-foil technique. From the measured data, the thick target yields of 64Cu were calculated and compared with experimental data available in the literature. The three investigated processes are discussed in comparison to the commonly used 64Ni(p,n)64Cu reaction for the production of 64Cu. As regards 67Cu production, the technical feasibility of the 70Zn(p,alpha)67Cu process was investigated. An electroplated isotopically enriched 70Zn target was developed which can withstand slanting beams of 20MeV protons of currents up to 20 microA. Methods for chemical separation of 67Cu and efficient recovery of the enriched target material were worked out. The method is suitable only for small-scale production of 67Cu.

Definition and treatment of lupus flares measured by the BILAG index

OBJECTIVES

The BILAG index is a clinical measure of lupus disease activity. It is valid, reliable and sensitive to change. Scoring in the BILAG index is based upon the physician's intention to treat. A flare of active lupus is defined as a new A or B score in at least one system. The main aim of this study was to determine whether patients with a lupus flare are treated as expected from the principles upon which the scoring system was devised. Secondly we wanted to establish whether patients with a new B score preceded by a C should be considered to have flared, as with patients scoring B following a D or E score.

METHODS

Over a 12-month period, 250 patients regularly attending lupus clinics in Birmingham and London were assessed using the BILAG index at each visit.

RESULTS

A new A or B score was observed in 154 (61.6%) patients. An A flare was observed in 26 (10.4%) patients. A B flare (in which the B score was preceded by a D or E score) was observed in 65 (26.0%) patients. There were 63 (25.2%) patients in whom there was a B score in a system in which a C score was previously recorded. Steroids were started or increased in 20 (77%) patients with an A flare. Almost all (92%) patients with a new A score had some increase in therapy. For the patients with new B scores, 53 (41%) had some increase in therapy, but multiple reasons were found for no change in therapy in 75 (59%) of these patients. There was no difference in the treatment of new B scores arising after a previous C score compared with previous D or E scores. Non-Caucasians were more likely to have a lupus flare than Caucasians.

CONCLUSIONS

These results are consistent with the principles upon which the BILAG index was devised and suggest that a moderate disease flare can be defined as a new B score following a C, D or E score according to the BILAG index.

A biological approach to treating disc degeneration: not for today, but maybe for tomorrow

The intervertebral disc unites the vertebrae in the spine, providing the flexibility required for bending and twisting and resisting the compression inflicted by gravity when in an upright posture. The discs have a complex structure, with the outer annulus fibrosus having lamellae of organized collagen fibrils and the inner nucleus pulposus having a more random collagen organization and an abundance of aggregating proteoglycans. This composite nature endows the disc with both the tension-resisting properties of a ligament and the compression-resisting properties of articular cartilage. Unfortunately, disc structure and function does not remain optimal throughout life, but undergoes progressive degeneration, commencing in the young adult, and is particularly evident in the nucleus pulposus. With time, disc degeneration may result in clinical symptoms, such as low back pain, and require medical intervention. Such treatment may involve removal of the offending disc by surgery rather than its repair, which would be the preferred course of action. In the near future, current bioengineering techniques may offer the possibility of repairing the damaged disc, if an engineered tissue with the appropriate functional properties can be generated to augment the ailing disc. In this report, we summarized our recent results, in which disc cells were implanted into a scaffold of collagen and hyaluronan, or entrapped into a chitosan gel, and growth factors were used to modulate matrix synthesis in an attempt to produce a tissue with a similar molecular composition to native nucleus pulposus tissue.