BackgroundThe registration trials of messenger RNA (mRNA) vaccines against SARS-CoV-2 did not address patients with inflammatory rheumatic diseases (IRD).ObjectiveTo assess the humoral response after two doses of mRNA vaccine against SARS-CoV-2, in patients with IRD treated with immunomodulating drugs and the impact on IRD activity.MethodsConsecutive patients treated at the rheumatology institute, who received their first SARS-CoV-2 (Pfizer) vaccine, were recruited to the study, at their routine visit. They were reassessed 4–6 weeks after receiving the second dose of vaccine, and blood samples were obtained for serology. IRD activity assessment and the vaccine side effects were documented during both visits. IgG antibodies (Abs) against SARS-CoV-2 were detected using the SARS-CoV-2 IgG II Quant (Abbott) assay.ResultsTwo hundred and sixty-four patients with stable disease, (mean(SD) age 57.6 (13.18) years, disease duration 11.06 (7.42) years), were recruited. The immunomodulatory therapy was not modified before or after the vaccination. After the second vaccination, 227 patients (86%) mounted IgG Ab against SARS-CoV-2 (mean (SD) 5830.8 (8937) AU/mL) and 37 patients (14%) did not, 22/37 were treated with B cell-depleting agents. The reported side effects of the vaccine were minor. The rheumatic disease remained stable in all patients.ConclusionsThe vast majority of patients with IRD developed a significant humoral response following the administration of the second dose of the Pfizer mRNA vaccine against SARS-CoV-2 virus. Only minor side effects were reported and no apparent impact on IRD activity was noted.

Since cardiac transplantation is limited by the small availability of donor organs, regeneration of the diseased myocardium by cell transplantation is an attractive therapeutic modality. To determine the compatibility of human embryonic stem cellderived cardiomyocytes (hESC-CMs) (7 to 55 days old) with the myocardium, we investigated their functional properties regarding intracellular Ca ] i transient and contraction, indicating that at this developmental stage, contraction depends on transsarcolemmal Ca 2؉ influx rather than on sarcoplasmic reticulum Ca 2؉ release. Third, in agreement with the notion that a voltage-dependent Ca 2؉ current is present in hESC-CMs and contributes to the mechanical function, verapamil completely blocked contraction. Fourth, whereas hESC-CMs expressed SERCA2 and NCX at levels comparable to those of the adult porcine myocardium, calsequestrin and phospholamban were not expressed. Our study shows for the first time that functional properties related to intracellular Ca 2؉ handling of hESC-CMs differ markedly from the adult myocardium, probably due to immature sarcoplasmic reticulum capacity. STEM CELLS 2006;24:236 -245

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On the basis of previous findings suggesting that in human embryonic stem cell-derived cardiomyocytes (hESC-CM) the sarcoplasmic reticulum Ca 2؉ -induced release of calcium machinery is either absent or immature, in the present study we tested the hypothesis that hESC-CM contain fully func-

Regeneration of the diseased myocardium by cardiac cell transplantation is an attractive therapeutic modality. Yet, because the transplanted cardiomyocytes should functionally integrate within the diseased myocardium, it is preferable that their properties resemble those of the host. To determine the functional adaptability of human embryonic stem cell-derived cardiomyocytes (hESC-CM) to the host myocardium, the authors investigated the excitation-contraction (E-C) coupling and the responsiveness to common physiological stimuli. The main findings are: (1) hESC-CM readily respond to electrical pacing and generate corresponding [Ca(2+)](i) transients (measured by fura-2 fluorescence) and contractions (measured by video edge detector). (2) In contrast to the mature myocardium, hESC-CM display negative force-frequency relations. (3) The hESC-CM contraction is dependent on [Ca(2+)](o) and blocked by verapamil. (4) Surprisingly, ryanodine, the sarcoplasmic-endoplasmic reticulum Ca(2+)-ATPase inhibitor thapsigargin, and caffeine do not affect the [Ca(2+)](i) transient or contraction. Collectively, these results indicate that at the developmental stage of 45 to 60 days, the contraction is largely dependent on [Ca(2+)](o) rather than on sarcoplasmic reticulum (SR) Ca(2+) stores. The results show for the first time that the E-C coupling properties of hESC-CM differ from the adult myocardium, probably due to immature SR function. Based on these findings, genetic manipulation of hESC-CM toward the adult myocardium should be considered.

Background: The registration trials of mRNA vaccines against SARS CoV2 did not address patients with autoimmune inflammatory rheumatoid diseases (AIRD). Aims: To assess the humoral response to mRNA vaccine against SARS CoV2, in AIRD patients treated with immunomodulating drugs and the impact on AIRD activity. Methods: Consecutive patients treated at the rheumatology institute who received their first SARS-CoV-2 (Pfizer) vaccine were recruited to the study, at their routine visit. The patients were invited for serology test 4-6 weeks after receiving the second dose of vaccine. IgG Antibodies (Ab) against SARS COV2 virus were detected using the SARS-Cov-2 IgG II Quant (Abbott) assay Results: One hundred fifty-six consecutive patients (76% females) treated at a single rheumatology center (mean age (range) 59.1 (21-83) years), mean (range) disease duration 10.8 (1-55) years), were recruited to the study. Thirty-five percents of patients received conventional synthetic (cs)DMARDs only, 64% biological/targeted synthetic (b/ts) DMARDs, 34% received combined treatment with csDMARDs and b/tsDMARDs and 32% corticosteroids (mean dose(range) 5.8mg(2.5-20mg) prednisone). One hundred thirty-seven patients (88%) were seropositive for IgG Ab against SARS CoV2 virus (median 2832.5 AU/ml, range 58-29499). Nineteen (12%) patients had negative tests, 11/19 were treated with B cell depleting agents. The reported side effects of the vaccine were minor (muscle sore, headache, low grade fever). The rheumatic disease remained stable in all patients. Conclusions: The vast majority of AIRD patients developed a significant humoral response following the administration of the second dose of the Pfeizer mRNA vaccine against SARS CoV2 virus. Only minor side effects were reported and no apparent impact on AIRD activity was noted.

Because previous findings showed that in human embryonic stem cell-derived cardiomyocytes (hESC-CM) the machinery for Ca2+-induced release of calcium is immature, we tested the hypothesis that hESC-CM contain functional 1,4,5-inositol triphosphate (IP3)-operated intracellular Ca2+ ([Ca2+]i) stores. We investigated the effects of angiotensin II (AT-II) and endothelin 1 (ET-1), which activate the 1,4,5-IP3 pathway, on [Ca2+]i transients and contractions in hESC-CM. Our major findings were that in hESC-CM, both AT-II (10(-9)-10(-7) M) and ET-1 (10(-9)-10(-7) M) exert inotropic and lusitropic effects. The involvement of 1,4,5-IP3-dependent intracellular Ca2+ release in AT-I-induced effects was supported by these findings: the effects of AT-II were blocked by 2-aminoethoxyphenyl borate (2-APB, a 1,4,5-IP3 receptor blocker) and U73122 (a phosopholipase C blocker); and hESC-CM express AT-II type 1 and IP3 type I and II receptors as determined by fluorescence immunostaining. In conclusion, hESC-CM exhibit functional AT-II and ET-1 signaling pathways, as well as 1,4,5-IP3-operated releasable Ca2+ stores.

Biallelic missense variants in can cause an attenuated form of the PLE and hypertriglyceridaemia syndrome. Our findings support the role of PLVAP in the pathophysiology of PLE, expand the phenotypic and mutation spectrums and underscore PLVAP's importance in EC barrier function in the gut.