Quantitative characterization of a repeated acute joint inflammation model in rats

1. Chronic pain owing to arthritis is a major clinical problem worldwide. To study the underlying pathological mechanisms of chronic pain and the effectiveness of different treatments, a number of experimental models have been developed over the years. 2. We introduced a new subchronic inflammatory model by repeated unilateral administration of carrageenan into the ankle joint of rats, and investigated the degree and the time-course of the oedema, and thermal and mechanical hyperalgesia. 3. Carrageenan (450 microg) was injected on three occasions (on days 1, 4 and 7), and the resulting oedema, thermal hyperalgesia (paw withdrawal test) and weight load were characterized in voluntarily walking rats daily for 15 days. The effect of diclofenac sodium (3 mg/kg orally daily for 15 days) was also determined. 4. Repetitive administration of carrageenan caused fluctuating oedema and pain responses, which did not normalize within 3 days. Exacerbated inflammatory oedema was observed after the second and third injections. Oedema and a decreased weight load of the inflamed paw were observed throughout the investigation period, and paw withdrawal thresholds to noxious thermal stimuli returned to baseline pre-carrageenan values from Day 13. 5. Oral diclofenac (3 mg/kg daily for 15 days) significantly decreased oedema within a few days (Day 3), whereas its anti-allodynic effect developed only several days later (Day 9). However, diclofenac at the applied dose did not influence the thermal hyperalgesia. 6. The results suggest that the repeated administration of carrageenan might be a suitable model for determining the effects of long-lasting treatment.     

Questions in diabetology to be elucidated

Despite advances in the management of cardiovascular diseases, the incidence of cardiovascular diseases is increasing both in developed and developing world. This phenomenon is associated with the worldwide pandemic of obesity and type 2 diabetes; both are related to the life style of urbanization. The association between life conduct of civilization and chronic stress resulting in augmentation of cardiovascular risk is detailed. Therapeutic policy practiced nowadays (polypill administration, achieving target values) in order to reduce cardiovascular risk is criticized. Primary causal role of chronic stress and life style, and secondary resultant nature of cardiovascular risk factors are stressed out in the pathogenesis of increased cardiovascular risk; therefore, limited value of an approach focusing on the management of cardiovascular risk factors, instead of targeting the primary cause, i.e. chronic stress and life conduct is emphasized. A short account is given about the similarities and dissimilarities in the pathogenesis of macro- and microangiopathy. The primary causal role of chronic stress in fetal and adult diabetes, furthermore possible triggers evoking chronic stress is discussed. Supportive experimental and clinical data are reported about the nature of basic metabolic dysregulation (dysmetabolism) in the pathogenesis of metabolic syndrome and type 2 diabetes. Besides the well documented significance of ischemic clinical manifestations of diabetes, the role of non-ischemic diabetic cardiomyopathy as an independent risk factor in evoking the total burden of cardiovascular risk in diabetes is emphasized. In reducing the cardiovascular risk in diabetics the management of high blood pressure and dyslipidemia is more effective compared to that of hyperglycemia. Besides managing cardiovascular risk factors, the successful treatment of dysmetabolism is importantly needed to eliminate the total excessive cardiovascular risk in diabetes. In order to achieve this goal the potential role of metabolic promoters is stressed out.     

Specific expression of PAD4 and citrullinated proteins in lung cancer is not associated with anti-CCP antibody production

Anti-citrullinated protein antibodies (ACPAs), produced against citrullinated proteins, are diagnostic and prognostic markers of rheumatoid arthritis (RA). The underlying mechanism that explains the connection of smoking, citrullination [catalyzed by peptidyl arginine deiminases (PADs)] and ACPAs is still unclarified in RA. Thus, we searched for a non-arthritic model in which an increased cell death allows the formation of autoantibodies. Data supporting that lung cancer might be a good candidate are as follows: (i) smoking plays a role in its pathogenesis, (ii) the disease is frequently accompanied by paraneoplastic syndrome, (iii) smoking increases citrullination in the lung, (iv) various types of malignancies are associated with increased citrullination and (v) lung cancer tissue shows similarities with RA synovium. Serum PAD4, rheumatoid factor (RF) and ACPA levels were measured in 42 lung cancer patients; expression of cytokeratin 7 (CK7), PAD4 and citrullinated proteins was visualized in 113 lung cancer tissues. All parameters were analyzed in correlation with smoking history. None of the patients had polyarthritis or autoimmune disease. Significantly increased RF levels were associated with higher PAD4 levels in smoker lung cancer patients compared with non-smokers. Both PAD4 and citrullination immunostaining strongly correlated with that of CK7 in lung cancer, however, did not differ according to smoking history. Two of 30 smoker lung cancer patients had high anti-cyclic citrullinated peptide levels. In conclusion, PAD4 and citrullination may be helpful in distinguishing lung cancer from healthy tissue. Smoking, abnormal serum PAD4 and RF levels may not be sufficient for the production of ACPAs and development of autoimmunity.     

Induction of arthritis in SCID mice by T cells specific for the “shared epitope” sequence in the G3 domain of human cartilage proteoglycan

Objective

To study the immunologic function and determine the fine epitope structure of a synthetic peptide p135H (²³⁷³TTYKRRLQKRSSRHP) of the G3 domain of human cartilage proteoglycan (aggrecan), which contains a highly homologous sequence motif of the shared epitope (QKRAA), the most common sequence motif in HLA–DR4 alleles, which predispose humans to the development of rheumatoid arthritis (RA).

Methods

Synthetic p135 peptides with altered sequences were used for (hyper)immunization of arthritis‐susceptible BALB/c mice and then challenged with a single dose of cartilage proteoglycan. Human p135 (p135H) and mouse p135 (p135M) synthetic peptides of the G3 domain of aggrecan were used to prime lymphocytes, which were then used for adoptive transfer of arthritis into “presensitized” SCID mice, determining cross‐reactivity among p135 peptides and their analogous sequences, and generating T cell hybridomas. T cell hybridomas were also used for arthritis transfer into SCID mice and for characterizing the fine epitope structure of T cell receptor (TCR) and major histo‐compatibility complex (MHC) binding sites of the immunogenic/arthritogenic p135H sequence.

Results

While p135H peptide‐(hyper)immunized mice became sensitized, they developed arthritis only after injection of a single dose of cartilage proteoglycan aggrecan. An altered peptide sequence (p135H‐AA) carrying the shared epitope motif (QKRAA) was as effective as the natural peptide p135H sequence for inducing arthritis. Mouse p135M‐specific lymphocytes induced arthritis with a lower incidence, but synthetic peptides to Escherichia coli heat‐shock protein (DnaJ) or HLA–DR4 allele (both having the shared epitope sequence with different flanking regions) were also positive. Fine epitope sequence recognition of an arthritogenic T cell hybridoma derived from p135H‐primed lymphocyte population was determined. Interestingly, in the most central position, a basic amino acid triplet of p135H peptide was found to be the MHC‐binding motif, whereas the flanking amino acids bound to the TCR.

Conclusion

Peptide p135H, corresponding to the peptide sequence in the G3 domain of human cartilage proteoglycan aggrecan, is immunogenic/arthritogenic in BALB/c mice. Peptide p135H includes a highly homologous motif of the shared epitope, a sequence that is overrepresented in bacterial heat‐shock proteins, envelope protein of human JC polyomavirus, and numerous HLA–DR4 alleles. Since the G3 domain of cartilage proteoglycan aggrecan with the p135 sequence is “lost” during the normal metabolic turnover of cartilage proteoglycan or in pathologic conditions, an antigenoriented T cell migration into joints of presensitized (susceptible) individuals may contribute to the organ‐specificity of RA.

     

Prevalence of suspected obesity hypoventilation syndrome in Hungarian Intensive Care Units during the COVID-19 pandemic

Introduction

The symptoms of obesity hypoventilation syndrome (OHS) may be present for years with concomitant progressive comorbidities, and the condition is frequently diagnosed late as a result of acute-on-chronic hypercapnic respiratory failure. Although some data exist on intensive care unit (ICU) prevalence, mortality and morbidity of OHS, little is known about the ICU mortality of these chronic respiratory failure patients during the COVID-19 pandemic.

Methods

We performed a cross-sectional observational study in five Hungarian Intensive Care Units for 4 months during the COVID-19 pandemic. All ICU patients were screened for OHS risk factors by treating physicians. Risk factors were defined as obesity (body mass index [BMI] ≥ 30 kg/m²) and at least one of the following: Epworth Sleepiness Score ≥ 6; symptoms of right heart failure; daytime or night-time hypoxemia; presence of loud snoring; witnessed apnoea. We calculated prevalence, mortality and factors associated with unfavourable outcome.

Results

A total of 904 ICU patients were screened for OHS risk factors. Overall 79 (8.74 ± 5.53%) patients were reported to have met the criteria for suspected OHS with a mortality rate of 40.5%; 69% (54 patients) of the cohort displayed at least 3 symptoms related to OHS before their acute illness. COVID-19 infection was associated with higher mortality in OHS-suspected patients, independently of actual BMI.

Conclusion

Despite the increased risk of obese patients, suspected OHS did not show higher prevalence than expected during the COVID-19 pandemic in critically ill patients. COVID-19 infection however was a risk for mortality in these patients, independent of actual BMI.     

Single center experience with the balloon-expandable Myval transcatheter aortic valve system with the first 100 patients: 30-day and 1-year follow-up

Aims

To report our single-center data, regarding the first 100 patients who underwent TAVR procedure with the new balloon-expandable MYVAL system. We report 30-day and 1-year outcomes in low to high-risk TAVR patient population.

Methods

From November 2019 to July 2021, 100 consecutive patients underwent TAVR procedure. Patient outcome was classified according to the VARC-2 definitions. The device performance was assessed using transthoracic echocardiography. Data collection was allowed by the Local Ethical Committee.

Results

The mean age was 74.7 years, 63 (63%) were male. The mean Euroscore II and STS score were 4.8 ± 4.9 and 5.6 ± 3.9, respectively. Transfemoral access was the most frequent (surgical vs. percutaneous 2% vs. 97%) and in one patient surgical subclavian access was used. VARC-2 outcomes were as follows: device success 99%, STROKE 1%, major and minor vascular complication was 1% and 11%, respectively, the rate of new permanent pacemaker implantation was 30.7%. At discharge, the incidence of grade I, grade II aortic regurgitation was 39% and 1%, respectively, without relevant PVL. In-hospital mortality was only 1%. These results included a high proportion (17%) of patients with bicuspid aortic valves. At 1 year, the all-cause mortality rate was 7% (only two due to cardiac event) and only a single patient had valve-related dysfunction requiring surgical aortic replacement.

Conclusions

TAVR procedure with MYVAL transcatheter heart valve system shows excellent 30-day and 1-year outcomes regarding patient survival, technical success, and valve-related adverse events. The limitations of our study comprise a single-center study with retrospective data collection.     

Proteoglycan-induced polyarthritis and spondylitis adoptively transferred to naive (nonimmunized) BALB/c mice

Mononuclear cells from BALB/c mice with progressive polyarthritis and spondylitis induced by injection of fetal human articular cartilage proteoglycan (PG) were used to transfer arthritis by intravenous injection into irradiated, nonimmunized syngeneic mice. Successful transfer of arthritis to BALB/c mice required the injection of lymphocytes from mice with arthritis, along with 50 m̈g of human fetal PG, or lymphocytes stimulated in vitro with either fetal human PG or with mouse cartilage PG. In addition, interleukin-2 or immune sera from animals with arthritis significantly reduced the time to onset of transferred disease. The onset of adoptively transferred arthritis, using cells and antigen, from the time of the first injection (38.2 ± 18.2 days, mean ± SD) was shortened if lymphocytes from mice with transferred arthritis were reinjected (retransferred) into other, irradiated syngeneic mice (6.1 ± 2.6 days). The appearance of autoreactive antibodies to mouse cartilage PG in the sera of mice with adoptively transferred arthritis (secondary or tertiary) preceded the appearance of the first clinical symptoms by a few days. The transfer of arthritis was blocked by pretreatment of donor (arthritic) lymphocytes with either anti-T cell or anti-B cell antibodies and complement. Exposure of mononuclear cells from mice with arthritis to PG, and its removal prior to transfer, also resulted in transfer of the arthritis. PG-induced arthritis was not transferred to nonirradiated mice, nor to irradiated mice injected with lymphocytes from animals with primary arthritis without chondroitinase ABC-digested fetal human PG. Arthritis never developed after injection of immune sera from mice with arthritis (without cells), nor when cells of nonarthritic animals were used with chondroitinase ABC-digested fetal human PG, with or without interleukin-2.