Epidemiology and clinical domains of Behçet's disease in the Cantabria region, Northern Spain.

OBJECTIVES: The prevalence of Behçet's disease (BD) has a considerable geographical and temporal variability. Data regarding epidemiology in Spain are limited. Our study aimed to assess the epidemiology and clinical domains of BD in a population-based cohort from Northern Spain and to compare the results with other geographical areas of other countries. METHODS: We conducted a cross-sectional study of a well-defined population in Northern Spain. Cases of suspected BD between January 1980 and December 2018 were identified. The diagnosis of BD was established according to the International Study Group (ISG) for Behçet's Disease. The incidence of BD between 1999 and 2018 was estimated by sex, age, and year of diagnosis. RESULTS: Of 120 patients with probable BD, 59 patients met ISG criteria and were finally included in the study, with a male/female ratio of 0.97; mean age 49.7±14.7 years. Incidence during the period of study was 0.492 per 100,000 people, observing an increase from January 1999 to December 2018. Prevalence was 10.14 per 100,000 inhabitants in 2018. Clinical manifestations were relapsing aphthous stomatitis (100%), genital ulcers (78%), skin involvement (84.7%), joint involvement (64.4%), uveitis (55.9%), central nervous system (16.9%), vascular (10.2%), and gastrointestinal manifestations (6.8%). CONCLUSIONS: The prevalence of BD in Cantabria is higher than in other Southern European countries. This difference may reflect a combination of geographic, genetic, or methodological variations, as well as the free accessibility to the Spanish Public Health System for the entire population. Clinical phenotypes observed are similar to those described in other world regions.

Long-term survival of renal transplantation in patients with lupus nephritis: experience from a single university centre.

OBJECTIVES: Lupus nephritis (LN) is a severe complication of systemic lupus erythematosus (SLE). Unfortunately, 10-20% of patients with LN develop end-stage renal disease (ESRD), and renal transplantation may be a therapeutic option. However, concerns about LN recurrence after transplant have been reported. We aimed to assess long-term post-transplant graft and patient survival in LN compared to patients with non-autoimmune nephropathy (polycystic kidney disease - PCKD). METHODS: We carried out a single-centre retrospective study of all patients who underwent renal transplantation due to LN in a referral unit between 1980 and 2018. This cohort was compared with a group of PCKD patients. The main outcome variables were graft and patient survival for up to 20 years, and the time-course of serum creatinine and proteinuria in the first 5 years after transplantation. Cumulative survival rates were estimated by the Kaplan-Meier method and compared using the log-rank test. RESULTS: We included 53 patients: LN group (n=21) and PCKD group (n=32). Baseline clinical characteristics were similar in both groups, except age at transplantation (39.8±11.3 years in the LN group and 46.6±5.0 years in the PCKD group; p=0.004). No significant differences were found regarding graft (p=0.59) or patient survival (p=0.087) at 20 years of follow-up. CONCLUSIONS: Despite concerns about LN recurrence after renal transplantation, this study shows that this procedure might be a safe alternative therapy for ESRD related to SLE and may provide long-term survival.

π-Bridge Substitution in DASAs: The Subtle Equilibrium between Photochemical Improvements and Thermal Control*.

Donor-acceptor Stenhouse adducts (DASAs) are playing an outstanding role as innovative and versatile photoswitches. Until now, all the efforts have been spent on modifying the donor and acceptor moieties to modulate the absorption energy and improve the cyclization and reversion kinetics. However, there is a strong dependence on specific structural modifications and a lack of predictive behavior, mostly owing to the complex photoswitching mechanism. Here, by means of a combined experimental and theoretical study, the effect of chemical modification of the π-bridge linking the donor and acceptor moieties is systematically explored, revealing the significant impact on the absorption, photocyclization, and relative stability of the open form. In particular, a position along the π-bridge is found to be the most suited to redshift the absorption while preserving the cyclization. However, thermal back-reaction to the initial isomer is blocked. These effects are explained in terms of an increased acceptor capability offered by the π-bridge substituent that can be modulated. This strategy opens the path toward derivatives with infra-red absorption and a potential anchoring point for further functionalization.

Clinical outcomes of hospitalised patients with COVID-19 and chronic inflammatory and autoimmune rheumatic diseases: a multicentric matched cohort study.

OBJECTIVES: The impact of inflammatory rheumatic diseases on COVID-19 severity is poorly known. Here, we compare the outcomes of a cohort of patients with rheumatic diseases with a matched control cohort to identify potential risk factors for severe illness. METHODS: In this comparative cohort study, we identified hospital PCR+COVID-19 rheumatic patients with chronic inflammatory arthritis (IA) or connective tissue diseases (CTDs). Non-rheumatic controls were randomly sampled 1:1 and matched by age, sex and PCR date. The main outcome was severe COVID-19, defined as death, invasive ventilation, intensive care unit admission or serious complications. We assessed the association between the outcome and the potential prognostic variables, adjusted by COVID-19 treatment, using logistic regression. RESULTS: The cohorts were composed of 456 rheumatic and non-rheumatic patients, in equal numbers. Mean age was 63 (IQR 53-78) years and male sex 41% in both cohorts. Rheumatic diseases were IA (60%) and CTD (40%). Most patients (74%) had been hospitalised, and the risk of severe COVID-19 was 31.6% in the rheumatic and 28.1% in the non-rheumatic cohort. Ageing, male sex and previous comorbidity (obesity, diabetes, hypertension, cardiovascular or lung disease) increased the risk in the rheumatic cohort by bivariate analysis. In logistic regression analysis, independent factors associated with severe COVID-19 were increased age (OR 4.83; 95% CI 2.78 to 8.36), male sex (1.93; CI 1.21 to 3.07) and having a CTD (OR 1.82; CI 1.00 to 3.30). CONCLUSION: In hospitalised patients with chronic inflammatory rheumatic diseases, having a CTD but not IA nor previous immunosuppressive therapies was associated with severe COVID-19.

The Number of Traditional Cardiovascular Risk Factors Is Independently Correlated with Disease Activity in Patients with Psoriatic Arthritis.

Background and objectives: Psoriatic arthritis (PsA) is associated with several comorbidities, including among others an increased risk of cardiovascular (CV) disease, atherosclerosis, metabolic syndrome, hypertension dyslipidemia, and diabetes. The purpose of the present study was to determine how the number of CV risk factors correlates with disease related data such as disease activity. Materials and Methods: Cross-sectional study that encompassed 305 patients who fulfilled the CASPAR criteria for PsA were assessed for lipid profile, disease activity measurements, and the presence of six traditional CV risk factors (diabetes mellitus, dyslipidemia, hypertension, obesity, chronic kidney disease, and smoking status). A multivariable regression analysis, adjusted for age, sex, and disease duration, was performed to evaluate if the number of classic CV risk factors was independently related with specific features of the disease, including disease activity. Results: Disease duration was found to be higher, after adjustment for age and sex, in patients with 1 or 2, and 3 or higher CV factors, compared to those patients without CV risk factors. Similarly, DAPSA (Disease Activity in PSoriatic Arthritis score) was found to be independently upregulated in patients with a higher number of CV risk factors. In this sense, as DAPSA score increases the odds ratio (OR) of having 1 or 2 (OR 1.12 (95% confidence interval (CI) 1.03-1.21), p = 0.010), and 3 or higher (OR 1.15 (95% CI 1.04-1.26), p = 0.004) CV factors was significantly higher compared to no CV risk factors category. This was independently found after adjustment for age, sex, and disease duration. Conclusions: PsA patients with a higher number of CV risk factors exhibit an upregulated disease activity compared to those without them. This is independent of disease duration and other demographics factors.

Synthesis and characterization of bis(4-amino-2-bromo-6-methoxy)azobenzene derivatives.

Aminoazobenzene derivatives with four ortho substituents with respect to the N-N double bond are a relatively unexplored class of azo compounds that show promise for use as photoswitches in biology. Tetra-ortho-methoxy-substituted aminoazobenzene compounds in particular can form azonium ions under physiological conditions and exhibit red-light photoswitching. Here, we report the synthesis and characterization of two bis(4-amino-2-bromo-6-methoxy)azobenzene derivatives. These compounds form red-light-absorbing azonium ions, but only under very acidic conditions (pH < 1). While the low pK a makes the azonium form unsuitable, the neutral versions of these compounds undergo trans-to-cis photoisomerization with blue-green light and exhibit slow (τ1/2 ≈ 10 min) thermal reversion and so may find applications under physiological conditions.

A biomimetic molecular switch at work: coupling photoisomerization dynamics to peptide structural rearrangement.

In spite of considerable interest in the design of molecular switches towards photo-controllable (bio)materials, few studies focused on the major influence of the surrounding environment on the switch photoreactivities. We present a combined experimental and computational study of a retinal-like molecular switch linked to a peptide, elucidating the effects on the photoreactivity and on the α-helix secondary structure. Temperature-dependent, femtosecond UV-vis transient absorption spectroscopy and high-level hybrid quantum mechanics/molecular mechanics methods were applied to describe the photoisomerization process and the subsequent peptide rearrangement. It was found that the conformational heterogeneity of the ground state peptide controls the excited state potential energy surface and the thermally activated population decay. Still, a reversible α-helix to α-hairpin conformational change is predicted, paving the way for a fine photocontrol of different secondary structure elements, hence (bio)molecular functions, using retinal-inspired molecular switches.

Highly Fluorescent Green Fluorescent Protein Chromophore Analogues Made by Decorating the Imidazolone Ring.

The synthesis and photophysical behavior of an unexplored family of green fluorescent protein (GFP)-like chromophore analogues is reported. The compound (Z)-4-(4-hydroxybenzylidene)-1-propyl-2-(propylamino)-1H-imidazol-5(4 H)-one (p-HBDNI, 2 a) exhibits significantly enhanced fluorescence properties relative to the parent compound (Z)-5-(4-hydroxybenzylidene)-2,3-dimethyl-3,5-dihydro-4H-imidazol-4-one (p-HBDI, 1). p-HBDNI was considered as a model system and the photophysical properties of other novel 2-amino-3,5-dihydro-4H-imidazol-4-one derivatives were evaluated. Time-dependent DFT calculations were carried out to rationalize the results. The analogue AIDNI (2 c), in which the 4-hydroxybenzyl group of p-HBDNI was replaced by an azaindole group, showed improved photophysical properties and potential for cell staining. The uptake and intracellular distribution of 2 c in living cells was investigated by confocal microscopy imaging.

Hydantoin-based molecular photoswitches.

A new family of molecular photoswitches based on arylidenehydantoins is described together with their synthesis and photochemical and photophysical studies. A series of hydantoin derivatives have been prepared as single isomers using simple and versatile chemistry in good yields. Our studies show that the photostationary states of these compounds can be easily controlled by means of external factors, such as the light source or filters. Moreover, the detailed investigations proved that these switches are efficient (i.e., they make efficient use of the light energy, are high fatigue resistant, and are very photostable). In some cases, the switches can be completely turned on/off, a desirable feature for specific applications. A series of theoretical calculations have also been carried out to understand the photoisomerization mechanism at the molecular level.

Epidemiology of Neuro-Behçet's Disease in Northern Spain 1999-2019: A Population-Based Study.

Background/Objectives: Neuro-Behçet's disease (NBD) is one of the most severe complications of Behçet's disease (BD). The incidence of NBD varies widely worldwide. This study aimed to estimate its current incidence in Northern Spain. Methods: This was a retrospective population-based cohort study of 120 patients in Northern Spain diagnosed with BD according to the 2013 International Criteria for BD (ICBD) between 1 January 1999 and 31 December 2019. NBD diagnoses were made according to International Consensus Recommendation (ICR) criteria. Overall, 96 patients were included, and their demographic and clinical data were collected. The incidence of NBD was estimated by age, gender, and year of diagnosis between 1999-2019. Results: NBD was diagnosed in 23 of 96 (24%) patients (15 women/8 men) (mean age: 44 ± 13.9 years). HLA-B51 was positive in 5 of 13 (38.4%) cases tested. A total of 10 (43.5%) patients had parenchymatous NBD, 10 (43.5%) had non-parenchymatous NBD, and 3 (13%) had mixed NBD. Incidence during the study period was 0.13 (95% CI, 0.11-0.26) per 100,000 people-years. There were no significant differences in gender in the incidence rate stratified by age (p > 0.05). Furthermore, there was a linear relationship with a mild decrease in age at diagnosis over time. Conclusions: Epidemiological characteristics of NBD in Northern Spain are similar to those of neighboring countries, except female gender predominance.