Masayuki Inouye

Glycated hemoglobin and lipid peroxidation in erythrocytes of diabetic patients.

In diabetes, glycation and subsequent browning (or glycoxidation) reactions are enhanced by elevated glucose concentrations. It is unclear whether the diabetic state per se also induces an increase in the generation of oxygen-derived free radicals (OFRs). However, there is some evidence that glycation itself may induce the formation of OFRs. OFRs cause oxidative damage to endogenous molecules, including cholesterol. 7-Oxocholesterol is known to be one of the major products of cholesterol oxidation. The level of cholesterol peroxidation products was assessed in erythrocyte membrane lipid by monitoring the peak height ratio of 7-oxocholesterol, one of the products of cholesterol peroxidation, to cholesterol with gas chromatography/mass spectrometry (GC/MS). The peak height ratio of 7-oxocholesterol to cholesterol was used as a biomarker of lipid peroxidation. The hemoglobin A1c (HbA1c) value, an index of glycemic stress, was measured by high-performance liquid chromatography. We examined the relationship between the levels of cholesterol peroxidation products and HbA1c in erythrocytes of diabetic and healthy subjects. There was a significantly increased ratio of 7-oxocholesterol to cholesterol in diabetic erythrocytes compared with control erythrocytes. The ratio of 7-oxocholesterol to cholesterol was significantly correlated with the level of HbA1c. This suggests that glycation of hemoglobin via chronic hyperglycemia is linked to cholesterol peroxidation in erythrocytes of both diabetic and healthy subjects.

Levels of lipid peroxidation product and glycated hemoglobin A1c in the erythrocytes of diabetic patients

In diabetes, the glycation and subsequent browning (or glycoxidation) reactions are enhanced by elevated glucose concentrations. It is unclear whether or not the diabetic state per se also induces an increase in the generation of oxygen-derived free radicals (OFRs). There is some evidence, however, that glycation itself may induce the formation of OFRs. OFRs could cause oxidative damage to endogenous molecules. We examined the relationship between the levels of lipid peroxidation and the levels of glycated hemoglobin A1c (GHbA1c) in erythrocytes of diabetic and healthy subjects. Lipid peroxidation was assessed in erythrocyte membrane lipids by monitoring peak height ratios of conjugated linoleic acid (CLA), one of the products of lipid peroxidation, to linoleic acid (LA) using gas chromatography-mass spectrometry (GC/MS). CLA is a collective term used to designate a mixture of positional and geometric isomers of LA in which the double bonds are conjugated. The peak height ratio of CLA to LA was used as a biomarker of lipid peroxidation. GHbA1c, an index of glycemic stress, was measured by high-performance liquid chromatography. There were significantly increased ratios of CLA to LA in diabetic erythrocytes compared with control erythrocytes. These ratios of CLA to LA were also significantly correlated with GHbA1c values. This suggests that glycation via chronic hyperglycemia links lipid peroxidation in the erythrocytes of both diabetic and healthy subjects.

Influence of admission functional status on functional change after stroke rehabilitation.

Inouye M, Hashimoto H, Mio T, Sumino K: Influence of admission functional status on functional change after stroke rehabilitation. Am J Phys Med Rehabil 2001; 80:121–125. ObjectiveTo determine whether the admission functional score influences the functional change after stroke rehabilitation. DesignTwo hundred forty-three patients who had received the Functional Independence Measure (FIMTM) assessment at admission and at discharge were enrolled in the study. The patients were stratified into three groups according to their FIM total scores at admission, i.e., ≦36, 37 to 72, and ≧73. ResultsThe Scheffé’s multiple comparison test showed that patients with FIM total scores of ≧73 at admission were significantly younger (58 ± 11 [SD] yr) than those who had scores of 37 to 72 (64 ± 11 yr) or ≦36 (66 ± 12 yr). Patients with FIM total scores of 37 to 72 at admission showed significantly higher FIM gain (37 ± 15) compared with those patients who had scores of ≧73 (20 ± 10) or ≦36 (29 ± 23). ConclusionThe functional levels of affected patients at admission stratified by the FIM scale roughly predict the degree of functional gain after rehabilitation in survivors with a first episode of ischemic stroke. Moderately affected patients will benefit from intensive rehabilitation. These findings may be useful for rehabilitation triage.

Link between glycation and lipoxidation in red blood cells in diabetes.

Oxidative stress is postulated to be increased in patients with diabetes mellitus. Glycation enhanced by elevated glucose concentrations may induce the formation of oxygen-derived free radicals (OFRs). OFRs would cause oxidative damage to endogenous molecules, including cholesterol. Accumulating evidence suggests that oxidative cell injury caused by OFRs contributes to the development of both macroangiopathy and microangiopathy in diabetes. Our previous studies have shown that 7-keto cholestadien is one of the major products of cholesterol peroxidation in diabetic erythrocyte membrane and its levels correlate with hemoglobin Alc (HbAlc) values. We have newly identified 3-cholesten-6-one, one of the minor products of cholesterol peroxidation, in it. The aim of our study is to investigate whether 3-cholesten-6-one levels also correlate with HbAlc values. Levels of 3-cholesten-6-one were assessed in erythrocyte membrane lipid by monitoring peak areas of 3-cholesten-6-one to cholesterol with gas chromatography-mass spectrometry. The peak area ratio of 3-cholesten-6-one to cholesterol was used as a marker of cholesterol peroxidation. The HbAlc value, an index of both glycemic stress and glycation, was measured by high-performance liquid chromatography. In this study, we evaluated 33 diabetic and 29 healthy subjects, matched for age (59.3+/-14.5 vs. 57.3+/-13.7 years, mean+/-S.D.) and sex (15 males and 14 females vs. 16 males and 17 females). There were both significantly raised HbAlc levels (4.6+/-0.8 vs. 8.3+/-2.4%, P<0.001) and significantly increased ratios of 3-cholesten-6-one to cholesterol (0.2+/-0.4 vs. 21+/-1.8, P<0.001) in diabetic patients compared to control subjects. A good correlation between HbAlc levels and ratios of 3-cholesten-6-one to cholesterol was found in participants (r = 0.75, P<0.001, y = 0.46x-1.8). This suggests that an oxidative stress exists in diabetes and the link between glycation and lipoxidation is found in diabetic red blood cell.

Formation of 9-hydroxy linoleic acid as a product of phospholipid peroxidation in diabetic erythrocyte membranes.

The increased production of oxygen-derived free radicals (OFR) and lipid peroxidation may contribute to vascular complications in diabetes. Some lipid peroxidation products have already been reported to be formed via glucose-induced oxidative stress. We have identified 9-hydroxy linoleic acid (9-OH-C18:2) in the red cell membrane phospholipid of diabetic subjects. We hypothesized that 9-OH-C18:2 would be formed in hydroxyl radical reactions to linoleic acid (C18:2) during glucose-induced oxidative stress, and confirmed that the formation of 9-OH-C18:2 was induced by ultraviolet (UV)-C irradiation to the synthetic C18:2. UV-C light generates highly reactive hydroxy radicals. C18:2 is confirmed to be the precursor of 9-OH-C18:2. To estimate the degree of oxidative damage to red cell membrane phospholipids, we developed a selective ion monitoring gas chromatography-mass spectrometric measurement for C18:2 and 9-OH-C18:2, following methanolysis of red cell membrane phospholipids. The relative peak height ratio of C18:2 to 9-OH-C18:2 (9-OH-C18:2/C18:2) was measured in phospholipid extracts of red cell membranes from healthy (n=29, 3.1+/-1.9%) and diabetic (n=27, 20. 9+/-16.1%) subjects. It was confirmed that 9-OH-C18:2/C18:2 is significantly (P<0.001) elevated in patients with diabetes. The measurement of 9-OH-C18:2/C18:2 in red cell membranes should be useful for assessing oxidative damage to membrane phospholipids in diabetes.

Stroke rehabilitation outcome study: A comparison of Japan with the United States

Murakami M, Inouye M: Stroke rehabilitation outcome study: A comparison of Japan with the United States. Am J Phys Med Rehabil 2002;81:279–282. Objective To compare demographics and functional outcomes in stroke rehabilitation in Japan and the United States. Design In Japan, 464 consecutive patients with first stroke were enrolled. The United States data were collected from the ninth annual report on patients discharged from medical rehabilitation hospital programs in the United States that subscribe to the Uniform Data System for Medical Rehabilitation. Results There are many differences between the two countries. Japanese survivors were 10 yr younger, were admitted to the rehabilitation hospital after a markedly longer period of time after the onset of the stroke, had comparably severe impairment on admission, had markedly longer lengths of stay, and had relatively severe disability at discharge. The mean or median admission FIM™ total score was comparable between Japan and the United States. The mean or median discharge FIM total score of Japanese patients was similar to that of the United States. Conclusions This may account for the lower rehabilitation efficiency for the Japanese patients. Mean admission FIM total scores in Japan were approximately the same as the discharge FIM scores in the United States data. Rate of discharge to the community was higher in Japan than in the United States.

Dicarboxylic acids as markers of fatty acid peroxidation in diabetes.

Increased urinary excretion of dicarboxylic acids (DAs) has been well known in patients with diabetic ketoacidosis (DKA). It was known that small amounts of such DAs were also detected in urine from healthy humans. Upon chemical, radiation-induced or enzymatic oxidation, cis-polyunsaturated fatty acids (PUFA) have previously been shown to generate saturated short- and medium-chain length DAs. In diabetes, it was confirmed that the imbalance between the generation of free radicals and antioxidant defense systems increases oxidative stress and leads to the damage of lipid, which contains PUFA. Some peroxidation products of PUFA, such as malondialdehyde and conjugated diene, are generally known to be elevated in patients with diabetes. The present study was undertaken to determine if urinary excretion of DAs is elevated in diabetic patients without DKA. Urine samples from ten non-ketoacidotic patients with type 2 diabetes and ten healthy subjects were examined for DAs by combined gas chromatography and mass spectrometry with selected ion monitoring. The diabetic subjects had significantly (Psebacic acid. Being stable and easily detectable compounds, DAs may be considered potential markers of oxidative attack on PUFA in diabetes.

Influence of initial status on functional gain for Japanese patients with first cerebral hemorrhage.

It is important to identify in advance patients who will achieve the greatest functional gains from rehabilitation therapy, as specialist rehabilitation resources are still scarce in Japan. The purpose of this study was to determine whether functional score at admission influences the functional change (functional score at discharge minus functional score at admission) after inpatient rehabilitation for first cerebral hemorrhage. One hundred and ninety-three patients with cerebral hemorrhage were enrolled in this study. They were assessed using the Functional Independence Measure (FIM) at admission and discharge and underwent inpatient rehabilitation treatment. Patients were stratified into 3 groups according to their FIM total scores on admission as follows: (1) < or = 36 (severely affected patient group); (2) 37-72 (moderately affected patient group); and (3) >73 (mildly affected patient group). Scheffes multiple comparison test showed that patients in group 1 were significantly older (mean +/- SD = 63 +/- 10 years) than those in groups 2 (56 +/- 10 years) or 3 (53 +/- 12 years). Patients in group 2 showed significantly greater FIM gain (37 +/- 17) compared with patients in groups 3 (23 +/- 12) or 1 (27 +/- 23). The results suggest that moderately affected patients at admission will show significantly higher functional gain compared with severely or mildly affected patients. Mildly affected patients at admission had a significantly shorter length of hospital stay for rehabilitation than the other groups. There was no significant difference in onset to admission interval between the 3 groups. The functional levels of affected patients on admission, as stratified by the FIM scale, roughly predict the degree of functional gain following rehabilitation in patients with first cerebral hemorrhage. Moderately affected patients will benefit from intensive rehabilitation. This study may be useful in determining how best to prioritize rehabilitation therapy.