Cardiac mesenchymal stromal cells are a source of adipocytes in arrhythmogenic cardiomyopathy.

AIM: Arrhythmogenic cardiomyopathy (ACM) is a genetic disorder mainly due to mutations in desmosomal genes, characterized by progressive fibro-adipose replacement of the myocardium, arrhythmias, and sudden death. It is still unclear which cell type is responsible for fibro-adipose substitution and which molecular mechanisms lead to this structural change. Cardiac mesenchymal stromal cells (C-MSC) are the most abundant cells in the heart, with propensity to differentiate into several cell types, including adipocytes, and their role in ACM is unknown. The aim of the present study was to investigate whether C-MSC contributed to excess adipocytes in patients with ACM. METHODS AND RESULTS: We found that, in ACM patients' explanted heart sections, cells actively differentiating into adipocytes are of mesenchymal origin. Therefore, we isolated C-MSC from endomyocardial biopsies of ACM and from not affected by arrhythmogenic cardiomyopathy (NON-ACM) (control) patients. We found that both ACM and control C-MSC express desmosomal genes, with ACM C-MSC showing lower expression of plakophilin (PKP2) protein vs. CONTROLS: Arrhythmogenic cardiomyopathy C-MSC cultured in adipogenic medium accumulated more lipid droplets than controls. Accordingly, the expression of adipogenic genes was higher in ACM vs. NON-ACM C-MSC, while expression of cell cycle and anti-adipogenic genes was lower. Both lipid accumulation and transcription reprogramming were dependent on PKP2 deficiency. CONCLUSIONS: Cardiac mesenchymal stromal cells contribute to the adipogenic substitution observed in ACM patients' hearts. Moreover, C-MSC from ACM patients recapitulate the features of ACM adipogenesis, representing a novel, scalable, patient-specific in vitro tool for future mechanistic studies.

Rtf1-mediated eukaryotic site-specific replication termination.

The molecular mechanisms mediating eukaryotic replication termination and pausing remain largely unknown. Here we present the molecular characterization of Rtf1 that mediates site-specific replication termination at the polar Schizosaccharomyces pombe barrier RTS1. We show that Rtf1 possesses two chimeric myb/SANT domains: one is able to interact with the repeated motifs encoded by the RTS1 element as well as the elements enhancer region, while the other shows only a weak DNA binding activity. In addition we show that the C-terminal tail of Rtf1 mediates self-interaction, and deletion of this tail has a dominant phenotype. Finally, we identify a point mutation in Rtf1 domain I that converts the RTS1 element into a replication barrier of the opposite polarity. Together our data establish that multiple protein DNA and protein-protein interactions between Rtf1 molecules and both the repeated motifs and the enhancer region of RTS1 are required for site-specific termination at the RTS1 element.

Effectiveness and safety of a nonremovable fiberglass off-bearing cast versus a therapeutic shoe in the treatment of neuropathic foot ulcers: a randomized study.

OBJECTIVE: To evaluate and compare the rate of reduction of the surface area of neuropathic plantar ulcers in diabetic patients treated with nonremovable rigidity-differentiated fiberglass off-bearing casts or a cloth shoe with a rigid sole with unloading alkaform insoles. The secondary aim was to evaluate the side effects and degree of patient acceptance of treatment. RESEARCH DESIGN AND METHODS: Fifty diabetic patients with neuropathic plantar ulcers were consecutively enrolled and randomized to one of two treatment groups. Of the 50 patients, 24 were treated with a specialized cloth shoe with a rigid sole and an unloading alkaform insole (shoe group), and 26 patients were treated with a nonremovable off-bearing fiberglass cast (cast group). All patients in both study groups returned to the clinic for weekly control visits. Their ulcers were treated with a standard dressing. Tracings of the ulcer area using a transparent dressing were performed on the day of entry to the study and after 30 days of treatment. The presence of new ulcerations caused by the use of the pressure-relief apparatus was recorded. Patient acceptance of the treatment was measured using a visual analog scale. RESULTS: At the end of the treatment period, an 8.3% increase of the ulcer area was observed in two patients in the shoe group, whereas in the cast group, no patient presented an increase. The reduction of the ulcer area was statistically more rapid in the cast group (Mann-Whitney test, P = 0.0004). Furthermore, the number of ulcers completely healed at the 30-day time point was 13 (50%) in the cast group and 5 (20.8%) in the shoe group (P = 0.03). In both groups, no side effects were recorded. The average score +/- SD of patient acceptance was 91.15 +/- 9.9 in the shoe group and 88.33 +/- 17.3 (NS) in the cast group. CONCLUSIONS: Our study has shown a significant difference in the speed of the reduction of neuropathic plantar ulcers treated with a fiberglass cast compared with a specialized cloth shoe. The use of fiberglass material with variable rigidity has also shown two important results: the elimination of side effects including ulcers caused by the cast, and high patient acceptance. These data show that the use of off-bearing casts made with fiberglass bandages of variable rigidity is the elective treatment of neuropathic plantar ulcers.

A comparative study on ferritin concentration in serum and bilateral bronchoalveolar lavage fluid of patients with peripheral lung cancer versus control subjects.

OBJECTIVES: To assess the diagnostic value of bronchoalveolar lavage fluid (BALF) ferritin as a lung tumor marker by comparing serum and BALF ferritin concentrations in patients with peripheral lung cancer versus control subjects with benign lung disease, and to examine the theory of ferritin compartmentalization around the tumor area by comparing ferritin concentrations in serum and bilateral (affected and unaffected side) BALF in cancer patients. METHODS: Four groups of patients were investigated: 10 control nonsmokers, 10 control smokers, 10 smokers with chronic obstructive pulmonary disease (COPD), and 22 patients with primary bronchogenic carcinoma. A bronchoalveolar lavage (BAL) was performed in all subjects (both sides in 13 oncological patients, one side in the others) and samples of BALF and blood were submitted to biochemical analysis. RESULTS: As a lung tumor marker, BALF ferritin showed 54% sensitivity and 93% specificity and serum ferritin 22% sensitivity and 93% specificity. A significant difference was observed between the two sides in the cancer patients (p = 0.033), and between BALF ferritin from the affected side and COPD patients (p = 0.025). Greater differences were obtained when BALF ferritin in the affected side of cancer patients was compared with values in both control nonsmokers (p < 0.0001) and control smokers (p < 0.001). CONCLUSIONS: These findings seem to confirm the relative diagnostic value of BALF ferritin as a lung tumor marker and the theory of ferritin compartmentalization. However, further studies are required to clarify the relations between iron and ferritin on the one hand and inflammation, tumorigenesis and host response on the other.