Biomedical subjects

Sari Mäkimattila

Publications and source records attributed to Sari Mäkimattila.

5 recordsLinked to original sources

PubMed2004

Acquired obesity is associated with increased liver fat, intra-abdominal fat, and insulin resistance in young adult monozygotic twins.

We determined whether acquired obesity is associated with increases in liver or intra-abdominal fat or impaired insulin sensitivity by studying monozygotic (MZ) twin pairs discordant and concordant for obesity. We studied nineteen 24- to 27-yr-old MZ twin pairs, with intrapair differences in body weight ranging from 0.1 to 24.7 kg [body mass index (BMI) range 20.0-33.9 kg/m2], identified from a population-based FinnTwin16 sample. Fat distribution was determined by magnetic resonance imaging, percent body fat by dual-energy X-ray absorptiometry, liver fat by proton spectroscopy, insulin sensitivity by measuring the fasting insulin concentration, and whole body insulin sensitivity by the euglycemic insulin clamp technique. Intrapair differences in BMI were significantly correlated with those in intra-abdominal fat (r = 0.82, P < 0.001) and liver fat (r = 0.57, P = 0.010). Intrapair differences in fasting insulin correlated with those in subcutaneous abdominal (r = 0.60, P = 0.008), intra-abdominal (r = 0.75, P = 0.0001) and liver (r = 0.49, P = 0.048) fat. Intrapair differences in whole body insulin sensitivity correlated with those in subcutaneous abdominal (r = -0.72, P = 0.001) and intra-abdominal (r = -0.55, P = 0.015) but not liver (r = -0.20, P = 0.20) fat. We conclude that acquired obesity is associated with increases in intra-abdominal and liver fat and insulin resistance, independent of genetic factors.

Absorptiometry, Photon↗

PubMed2004

Brain metabolic alterations in patients with type 1 diabetes-hyperglycemia-induced injury.

Microangiopathic end-organ injury is common in type 1 diabetes. However, the pathophysiology of diabetic encephalopathy is poorly understood. The authors studied 10 normotensive patients with type 1 diabetes with retinopathy, autonomic neuropathy, but without nephropathy, and 10 healthy subjects. Proton magnetic resonance spectroscopy was performed at 1.5 T in the frontal cortex, thalamus, and posterior frontal white matter. There was no change in N-acetyl-containing compounds (NA), but choline-containing compounds (Cho) were increased in the white matter and in the thalamus; myo-inositol was increased in the white matter, glucose excess was found in all brain, and water intensity was increased in the cortical voxel in the patients. Calculated lifetime glycemic exposure correlated inversely with Cho and NA in white matter and with Cho in thalamus. Concentrations of soluble intercellular adhesion molecules and vascular cell adhesion molecules were increased in the patients. In conclusion, in patients with type 1 diabetes, the increase in adhesion molecules and an association between altered brain metabolites and glycemic exposure suggest the presence of a vascularly mediated, progressive metabolic disturbance in the brain.

Adult↗

PubMed2004

Effects of rosiglitazone and metformin on liver fat content, hepatic insulin resistance, insulin clearance, and gene expression in adipose tissue in patients with type 2 diabetes.

Both rosiglitazone and metformin increase hepatic insulin sensitivity, but their mechanism of action has not been compared in humans. The objective of this study was to compare the effects of rosiglitazone and metformin treatment on liver fat content, hepatic insulin sensitivity, insulin clearance, and gene expression in adipose tissue and serum adiponectin concentrations in type 2 diabetes. A total of 20 drug-naive patients with type 2 diabetes (age 48 +/- 3 years, fasting plasma glucose 152 +/- 9 mg/dl, BMI 30.6 +/- 0.8 kg/m2) were treated in a double-blind randomized fashion with either 8 mg rosiglitazone or 2 g metformin for 16 weeks. Both drugs similarly decreased HbA1c, insulin, and free fatty acid concentrations. Body weight decreased in the metformin (84 +/- 4 vs. 82 +/- 4 kg, P < 0.05) but not the rosiglitazone group. Liver fat (proton spectroscopy) was decreased with rosiglitazone by 51% (15 +/- 3 vs. 7 +/- 1%, 0 vs. 16 weeks, P = 0.003) but not by metformin (13 +/- 3 to 14 +/- 3%, NS). Rosiglitazone (16 +/- 2 vs. 20 +/- 1 ml.kg(-1).min(-1), P = 0.02) but not metformin increased insulin clearance by 20%. Hepatic insulin sensitivity in the basal state increased similarly in both groups. Insulin-stimulated glucose uptake increased significantly with rosiglitazone but not with metformin. Serum adiponectin concentrations increased by 123% with rosiglitazone but remained unchanged during metformin treatment. The decrease of serum adiponectin concentrations correlated with the decrease in liver fat (r = -0.74, P < 0.001). Rosiglitazone but not metformin significantly increased expression of peroxisome proliferator-activated receptor-gamma, adiponectin, and lipoprotein lipase in adipose tissue. In conclusion, rosiglitazone but not metformin decreases liver fat and increases insulin clearance. The decrease in liver fat by rosiglitazone is associated with an increase in serum adiponectin concentrations. Both agents increase hepatic insulin sensitivity, but only rosiglitazone increases peripheral glucose uptake.

Adipose Tissue↗

PubMed2002

Impaired responsiveness to NO in newly diagnosed patients with rheumatoid arthritis.

OBJECTIVE: Cardiovascular disease is the major cause of excessive mortality in patients with rheumatoid arthritis (RA). We determined whether endothelial dysfunction characterizes patients with newly diagnosed RA (n=10) compared with normal subjects (control group, n=33) and whether it is reversible with 6 months of anti-inflammatory therapy. METHODS AND RESULTS: Endothelial function was determined by measuring vasodilatory responses to intrabrachial artery infusions of acetylcholine (ACh at 7.5 and 15 microg/min, low and high dose, respectively), an endothelium-dependent vasodilator, and to sodium nitroprusside (SNP, 3 and 10 micro g/min), an endothelium-independent vasodilator. Before treatment, blood flow responses (fold increase in flow) to low-dose SNP were 30% lower in the RA versus the control group (4.1+/-0.4-fold versus 5.9+/-0.5-fold, respectively), and responses to high-dose SNP were 34% lower in the RA group versus the control group (5.1+/-0.6-fold versus 7.7+/-0.7-fold, respectively; P<0.001). The responses to low-dose ACh were 50% lower in the RA group versus the control group (3.0+/-0.5-fold versus 6.6+/-0.7-fold, respectively), and responses to high-dose ACh were 37% lower in the RA group versus the control group (5.0+/-0.4-fold versus 7.9+/-0.8-fold, respectively; P<0.001). After therapy, clinical and laboratory markers of inflammation had significantly decreased. Blood flow responses to ACh increased significantly (P=0.02). CONCLUSIONS: We conclude that newly diagnosed patients with RA have vascular dysfunction, which is reversible with successful therapy. Therefore, early suppression of inflammatory activity may reduce long-term vascular damage.

Acetylcholine↗

PubMed2002

Endothelial dysfunction in human diabetes.

In nondiabetic individuals, a poor response to an endothelium-dependent vasodilator in coronary vessels has been shown to increase the likelihood of a future cardiovascular event. Such prospective data are not as yet available in patients with type 1 or type 2 diabetes. However, consistent with the greatly increased cardiovascular risk in these patients, endothelial dysfunction has been almost universally found to characterize patients with type 2 diabetes particularly. Endothelial dysfunction frequently coexists with features of insulin resistance, such as the presence of small dense low-density lipoprotein (LDL) particles even in nondiabetic individuals. This association is independent of obesity and other causes of endothelial dysfunction, such as LDL cholesterol, hypertension, and smoking. In patients with type 1 diabetes, endothelial dysfunction has been found in approximately half of the studies. In some but not all studies, endothelial dysfunction has been especially severe in patients with poor glycemic control. Reversal or amelioration of endothelial dysfunction has been documented by many commonly used therapeutic agents such as successful insulin therapy, fibrates, and angiotensin-converting enzyme inhibitors, but also with some but not all agents that act as antioxidants. Long-term studies addressing the prognostic significance of endothelial dysfunction and its reversal are urgently needed to determine whether measurement of endothelial function could be used to identify individuals at risk better than can be done at present using classic risk factor assessment among patients with type 2 diabetes especially.

Animals↗