Single cell profiling of adipose tissue in atherosclerosis

Funding Acknowledgements

Type of funding sources: Foundation. Main funding source(s): Academy of Finland

Sigrid Jusélius Foundation

Adipose tissue influences the physiological and pathological processes in our body by regulating lipid storage and metabolic homeostasis. Extracellular matrix (ECM) is a dynamic and complex assemblage consisting of polysaccharides, proteogylcans and signalling proteins. Though both adipocytes and non- adipose cells of the stromal fraction contribute to ECM maintenance, role of adipose tissue ECM in the disease remains poorly characterised. High fat diet (HFD) and obesity represent major risk factors for atherosclerosis. Our overall aim in this study was to understand HFD induced changes in the adipose tissue during atherosclerosis progression using single cell RNA sequencing (scRNA-seq), to identify the ligands responsible for changes in the expression of ECM components and to characterise the role of ECM protein fibrillin in disease associated tissue changes.

We performed scRNA-seq in the adipose tissue of control mice and atherosclerotic LDLR-/- / ApoB100/100 subjected to 1 (early disease) or 3 months (advanced disease) of HFD. This allowed us to identify 13 different cell types in the adipose tissue of the diseased mice. Among them, we identified mesenchymal cells (MSC) undergoing changes from putatively adipogenic to fibrogenic cells. The differentially expressed genes in the MSC population exhibited functions related to ECM development, maintenance and signalling. We identified Fibrillin-1 (Fbn1) as one of the most prominent up regulated genes and studied the effect of Fbn1 knockout in ApoE-/- Fbn1C1039G+/- mice. The Fbn1 knockout mice model suited our experimental design to study the adipose tissue during atherosclerosis as the mice developed significantly large and unstable plaques characterised by large necrotic core. Our results demonstrated that adipose tissue expresses a new subtype with HFD in Fbn1 knockout mice, which could be associated with insulin resistance and fat accumulation. Fbn1 knockout led to an altered phenotype of MSCs (or adipocytes) in adipose tissue.

Altogether, our analysis provides the first steps toward understanding the role of MSCs in ECM-related changes during atherosclerosis and HFD stimulation.

Coping in spouses of patients with acute myocardial infarction in the early phase of recovery

The purpose of this study was (1) to determine the coping strategies employed by spouses of patients with AMI in the early phase of the crisis, (2) to define the role of age, gender, health perception, time since infarction, spouses' fears, and negative life events in the choice of coping strategies applied, and (3) to test the effect of coping strategies on physical and psychological strain. Fifty-seven spouses participated in the study, 47 were female and 10 were male. Data were collected by structured questionnaires, which were distributed to the spouses from 2 weeks-4 months after the patient's AMI. The researchers found that age, negative life event during the last 12 months, time since infarction, and the spouse's fears influenced the choice of strategies. In the early stage of the crisis, positive reappraisal seems to be a strategy that increased physical strain. Spouses' need for social support in the early stage of the crisis is a factor for health care providers to bear in mind. Besides giving information, empathy, and understanding, health care personnel can try to assist spouses in their efforts to reappraise their situation.

Myocardial infarction, spouses' reactions and their need of support

The purpose of this study was to investigate the impact of myocardial infarction (MI) on survivor's spouses in terms of fears and symptoms during the patient's recovery period. In addition the researchers sought to evaluate the influence of the support by the health care professionals on spouses' adjustment. A total of 57 Finnish spouses participated in the study. Of the spouses 47 were female and 10 were male. Data were collected using a structured questionnaire distributed to the spouses at a rehabilitation session at 2 weeks-4 months after the MI. Topics covered included fears, emotional and physical symptoms and the spouses' experience of the sufficiency of the support that they had received from health care professionals during the patient's recovery. Data were analysed using quantitative methods including descriptive statistics and multivariate methods. Fears and symptoms were classified using factor analyses. For fears two factors emerged which were named: disease-related fears and personal fears. In respect of symptoms experienced by the spouse three factors emerged: one which describes emotional distress, one which describes dysfunction and one describing spouses' own vulnerability. The significantly most intensively experienced fears by the spouses were the disease-related fears followed by the personal fears. The most frequently reported symptom was dysfunction followed by emotional distress and vulnerability. In regression analysis emotional distress was predicted by personal fears, support from the health care professionals, the shock reaction, spouse's own health and time after MI. Dysfunction was predicted by spouse's own health and personal fears whereas vulnerability was predicted by spouse's own health and support from the health care professionals. Study findings show that in the planning of the care of patients with MI it is important to attend to the reactions and needs of spouses. Their resources are required for optimal rehabilitation of the patient.

Preoperative hook-wire localization of nonpalpable breast lesions by use of standard and stereotactic technique

A series of 151 women underwent 153 preoperative hook-wire localization of nonpalpable breast lesions, all of them without reinserting the needle. Measured by our criteria, the success for localization procedure was stereotactically 73% and conventionally 47%. Measured by criteria of surgeon acceptability and evidence of successful removal of the lesion, the success rate for localization was stereotactically 84% and conventionally 97%. Failure to remove the suspicious lesion in our series was more common after stereotactical than conventional localization with larger specimens. At present our experience and results of stereotactic wire localization are improving. We believe that the stereotactic wire localization without previous checking of the needle position is accurate and shortens the time required for the whole procedure.

Serum cortisol and outcome of ischemic brain infarction

The predictive value of serum cortisol level on the prognosis in acute brain infarction of the carotid circulation territory was studied in 101 patients younger than 70 years. The levels of 7 a.m. and 7 p.m. serum cortisol were measured initially and at 1 week. All patients underwent a computed cerebral tomography (CT) within 2 days of the onset of symptoms, and a second CT 3 weeks or 3 month later. Serum cortisol values predicted the stroke outcome. Both the 7 a.m. and the 7 p.m. values in the initial and 1-week samples correlated positively with the severity of hemiparesis on the corresponding days. The 7 p.m. values predicted better than the 7 a.m. values the functional outcome and case fatality during the 3 month follow-up. Initially and at 1 week, the median 7 p.m. serum cortisol values were statistically significantly higher in those with frontally extending infarcts than in those with non-frontal infarcts. Both 7 a.m. fasting blood glucose and glycosylated hemoglobin (HbA1c) measurements were taken within 3 days of the onset in 95 cases. The patients were diagnosed to have prestroke normoglycemia (n = 73) and hyperglycemia (n = 22) on the basis of the HbA1c level. A highly significant (P = 0.0001) correlation was demonstrated between the initial 7 p.m. cortisol and 7 a.m. fasting blood glucose values in those with prestroke normoglycemia, suggesting that hyperglycemia during the acute phase of stroke is a stress response.

Blood glucose, glycosylated haemoglobin, and outcome of ischemic brain infarction

From August 1987 through December 1989 all consecutive conscious patients younger than 70 years with a recent (less than 48 h) brain infarction of the carotid territory were prospectively included in the study. Blood samples for fasting blood glucose and glycosylated haemoglobin (HbA1c) were taken after a median delay of 23 h of the onset of symptoms. The severity of hemiparesis was assessed on admission, at 1 week, 3 weeks, and 3 months. The functional outcome was assessed at 3 months. Computed cerebral tomography was performed on admission, and later on at 3 weeks or 3 months. The brain infarct volume was measured from the CTs. The patients were diagnosed to have prestroke normoglycemia (n = 76) and prestroke hyperglycemia (n = 23) on basis of the HbA1c level. The case fatality rate, severity of hemiparesis, functional outcome, and infarct size did not differ between these 2 groups. On the other hand, fasting blood glucose level of the non-diabetics correlated strongly with the severity of hemiparesis and predicted stroke outcome. A statistically significant correlation was observed between blood glucose values and the volumes of cortical infarcts in non-diabetics. Because prestroke blood glucose level, in contrast to post-stroke blood glucose level, did not have any predictive value concerning stroke outcome it is concluded that high fasting blood glucose values after stroke reflect a stress response to a more severe ischemic brain lesion.

Pleural and pulmonary complications after bilateral internal mammary artery grafting

The long-term patency of internal mammary artery (IMA) grafts in coronary bypass surgery is superior to that of saphenous vein grafts. To investigate if bilateral IMA grafting increases the complication rate, especially pleural problems, 100 patients with bilateral and 100 with unilateral IMA grafts were retrospectively studied. Preoperatively the groups did not differ in age, previous myocardial infarction, ejection fraction, NYHA classification or previous respiratory disease, but the coronary artery status was poorer in the bilateral IMA group. Postoperative pleural drainage was greater after bilateral IMA grafting (1074 vs. 497 ml, p less than 0.0001). Reoperation was required for bleeding in 10% of the patients with unilateral, and 20% of those with bilateral IMA grafting (p less than 0.05), and more blood was transfused in the latter group (5.9 vs. 4.7 units, p less than 0.01). Pleural effusion at discharge from hospital or 3 months postoperatively, pain in the sternotomy wound, pain on breathing and postoperative use of nitroglycerin did not differ significantly between the groups. Bilateral IMA grafting thus led to more bleeding and reoperations than single IMA grafting, but did not cause excessive pulmonary complications.