ORIGINAL RESEARCH RELATION OF SERUM S-100 PROTEIN TO INFARCT SIZE AND CLINICAL PROGNOSIS 1 Gülay Kenangil1, A.Destina Yalçın1, Gonca Haklar2, Hasan Cacina2, Hulki Forta1 Neurology Clinic,Şişli Etfal Education and Research Hospital, Istanbul, Turkey 2 Department of Biochemistry, School of Medicine, Marmara University, Istanbul, Turkey ABSTRACT Objectives: To analyze serum concentrations of S-100 protein in acute ischemic stroke and to determine its correlation to infarct size and clinical prognosis. Methods: Serum samples were collected from 26 acute ischemic stroke patients on admission and on the third and seventh days. Serum S-100 protein levels were measured using Smart S-100 protein detection reagent. The lesions were classified as supratentorial middle cerebral artery infarctions and infratentorial brainstem infarctions. All patients had cranial computerized tomography (CT) scan in the first 24 hours and magnetic resonance imaging (MRI) or CT scan in the first week. Neurological evaluation was made with the National Institute of Health Stroke Scale (NIHSS) in the acute stage and with Modified Barthel Index (MBI) in the 1st and 6th months. ANOVA was used for statistical analysis. Results: MCA infarctions greater than 2/3 of MCA territory had highest S100 protein levels on day 3, greater scores on NIHSS and smaller scores on MBI. Serum S-100 was undetectable in the infratentorial infarction group. Conclusion: S-100 protein is correlated with the infarct size and prognosis in MCA lesions and its rise on the 3rd day may reflect edema. Keywords: S-100 protein, Ischemic stroke, Prognosis,Iinfarct size SERUM S-100 PROTEİNİNİN ENFARKT BOYUTU VE KLİNİK PROGNOZ İLE İLİŞKİSİ ÖZET Amaç: Akut iskemik inmelerde serum S-100 protein konsantrasyonlarının ölçülmesi ile enfarkt boyutu ve klinik prognoz ile olan korelasyonlarının belirlenmesi Yöntemler: Serum örnekleri 26 akut iskemik inmeli olgudan başvuru sırasında, 3. ve 7. günlerde toplandı. Serum S-100 protein düzeyleri Smart S-100 protein saptama reaktifi ile ölçüldü. Lezyonlar supratentoryal orta serebral arter (middle cerebral artery, MCA) enfarktları ve infratentoryal beyin sapı enfarktları olarak sınıflandırıldı. Tüm hastaların ilk 24 saat içinde çekilmiş kraniyal kompüterize tomografileri (computerized tomography, CT) ve ilk hafta içinde çekilmiş manyetik rezonans görüntülemeleri veya CT’leri mevcuttu. Nörolojik incelemeleri akut evrede “National Institute of Health Stroke Scale (NIHSS)” ile, 1. ve 6. aylarda “Modified Barthel Index (MBI)” ile yapıldı. İstatistiksel analizlerde ANOVA kullanıldı. Bulgular: MCA bölgesinin 2/3’ünden fazlasını tutan MCA enfarktları 3. günde en yüksek S-100 protein değerlerine, en yüksek NIHSS ve en düşük MBI skorlarına sahipti. İnfratentoryal enfarkt grubunda serum S-100 proteini ölçülemez düzeydeydi. Sonuç: MCA lezyonlarında S-100 proteini enfarkt boyu ve klinik prognoz ile ilişkilidir ve 3. gündeki artış ödem göstergesi olabilir. Anahtar Kelimeler: S-100 proteini, İskemik inme, Prognoz, Enfarkt boyutu INTRODUCTION exhibit regulatory effects on cell growth and differentiation as well as on cell shape and energy metabolism 4. In previous studies, the elevation of S-100 B protein in cerebrospinal fluid (CSF) was reported in various conditions, including acute cerebral damage such as head trauma, cerebral hypoxia, cerebral bleeding and ischemic stroke 5-7. The difficulty of collecting CSF samples by lumbar puncture urged investigators to study such biochemical markers in blood. In this study we have aimed to evaluate whether serial Neurobiochemical markers of brain damage gained particular attention in the identification of stroke in recent years. S-100 protein is a dimeric, acidic calcium binding protein (MW: 21,000 daltons) which is a major component of the cytosol particularly in astroglial cells. The protein is metabolized and eliminated by the kidney, its biological half-life is approximately 2 hours 1-2. S100 protein has two subunits, S-100 B and S-100 A 3. S-100 protein B fraction has been shown to Corresponding author: Gülay Kenangil Yeni Çamlıca Mah. Duman Sok. No: 50.7000 A Konutları 3/20 Umraniye, Istanbul, Turkey. E-mail: kenangil@superonline.com Marmara Medical Journal 2004;17(3);105-108 105 Marmara Medical Journal 2004;17(3);105-108 Gülay Kenangil, et al. Relation Of Serum S-100 Protein To Infarct Size and Clinical Prognosis considered significant when probability was p < 0.05. One of our patients with large MCA infarction died on the 10th day of admission because of heart failure. (We were able to take his blood samples.) His NIH score was 19 and his MBI score was accepted as zero for both the first and the 6th month. measurements of blood S-100 B protein level correlate with the infarct size and the clinical prognosis in acute ischemic stroke. METHODS The study was approved by the Ethical Committee of Marmara University Medical Faculty. S-100 B serum levels were determined in 26 patients with acute ischemic stroke (15 men, 11 women; mean age 65.1 ± 13.35) admitted to our hospital within the first 24 hours of stroke onset. Patients were classified according to the size and localization of the infarcts as, supratentorial large middle cerebral artery (MCA) infarctions greater than 2/3 of MCA territory (n=6), medium MCA infarctions between 1/3 to 2/3 of MCA territory (n=7), small MCA infarctions smaller than 1/3 of MCA territory (n=6), and infratentorial brainstem infarctions (n=7). The localization of infarcts was made by vascular mapping of Tatu and his friends 8 . All patients had neurological examination and cranial CT scan in the first 24 hours and cranial CT or MRI in the first week. Blood samples were collected on admission and on the third and seventh days. S-100 B protein levels were measured by an ELISA method (Smart S-100 protein, Skye Pharma Tech. Inc, Canada). Neurological evaluation was made by National Institute of Health Stroke Scale (NIHSS) in the acute stage and by Modified Barthel Index (MBI) on the first and sixth months. NIHSS scores were as follows: 1-7 mild neurological deficit, 8-14 moderate neurological deficit, ≥ 15 severe neurological deficit. In MBI the maximum score was 20, meaningfull independency. Score 0 was the worst, meaning full dependency. Statistical analyses were made using the Instat 2.0 programme. Data were given as mean ± SEM. Repeated measures of ANOVA with TukeyKramer Multiple comparison test was used for the statistical analysis and the differences were RESULTS Patients were divided into 4 groups according to localization and size of the lesion seen on the CT or MRI. Groups were as follows: Large MCA infarctions (greater than 2/3 of MCA territory, Table I), medium MCA infarctions (1/3-2/3 of MCA territory), small MCA infarctions (smaller than 1/3 of MCA territory), and infratentorial brainstem infarctions (Table II). Five of the brainstem lesions were in pons, located in paramedian region and greater than 1.5 cm. The other two lesions were very large and one of them was located along both lateral medulla and cerebellum. The other had scattered lesions in pons, midbrain and thalamus. Serum S-100 protein levels are given in Table III. Serum S-100 B protein was undetectable in the brainstem infarctions. In large MCA infarctions serum S-100 B protein concentration was significantly higher in 3rd day samples when compared to samples taken on admission (p<0.05). However, there was no difference between levels on admission and at 7th day or 3rd and 7th day samples. There was no statistical significance between S-100 B levels on admission, at 3rd day and/or 7th day for patients with medium and small MCA infarctions. There were significant correlations between S-100 protein concentrations and MBI scores in large MCA infarctions (p<0.05 for both first and sixth month evaluations) but the correlation between S100 protein concentrations and NIHSS was not significant. Table I: Data on large MCA infarctions Patients Age Gender National Institute of Health Stroke Scale Modified Barthel Index (First month) Modified Barthel Index (Sixth month) 1 2 58 68 M M 19 19 0 0 0 0 3 4 5 81 98 62 W M M 14 16 18 0 0 8 0 0 12 6 63 W 17 9 12 106 Marmara Medical Journal 2004;17(3);105-108 Gülay Kenangil, et al. Relation Of Serum S-100 Protein To Infarct Size and Clinical Prognosis Table II: Data on Brainstem infarctions Patient No. Age Gender 20 21 22 23 24 25 26 78 51 63 57 47 61 35 M W M M M W W National Institute of Health Stroke Scale 8 5 13 0 3 6 3 Modified Barthel Index (First month) Modified Barthel Index (Sixth month ) 15 20 16 20 20 20 20 20 20 20 20 20 20 20 Table III: Serum S-100 levels (ng/L) in MCA infarctions Day 0 Large MCA infarctions (n=6) Medium MCA infarctions (n=7) Small MCA infarctions (n=6) Day 3 18 ± 7 114 ± 29 *,** Day 7 40 ± 19 12 ± 5 13 ± 7 5±2 1 ± 0.4 1.5 ± 0.8 3.3 ± 2.4 outcome 15. Büttner et al. 12 studied serum S-100 protein levels after MCA infarctions in relation to clinical data and prognosis. Patients with extensive ischemic edema (rather than patients with small lesions) were characterized by high S100 levels in serum. In our study we evaluated the infarctions in MCA territory and divided them into 3 groups according to their size. Patients with large MCA infarctions had the highest serum S100 levels on day 3 and their short and long-term prognosis were the worst of all. According to our knowledge large MCA infarctions had maximum edema on day 2 and 3, therefore we agree with Büttner that S-100 levels can reflect cerebral edema. Smaller artery groups had no significant rise in serum S-100 on day 0, 3 or 7. In large MCA infarctions there was no significant correlation between third day S-100 values and NIHSS but there was a statistically significant correlation between third day S-100 values and the first and sixth month MBI. The prognosis was the worst in large MCA infarctions and they had the smallest scores in MBI. Therefore, we conclude that in large ischemic infarctions MBI is a good index for showing the clinical prognosis. In more recent reports Wunderlich et al. 16 reported that patients with cerebellar or brainstem lesions showed better functional outcome at discharge from the hospital. In our infratentorial infarction group, lesions with different size were located in different infratentorial areas. DISCUSSION Many markers of ischemic brain damage such as S-100 B, neuron specific enolase (NSE), glial fibrillary acidic protein (GFAP), myelin basic protein (MBP) have been investigated after acute ischemic stroke 9-10. Persson et al. 11 were the first to study S-100 protein in blood and found elevations in two patients. Elevation of serum S100 protein B levels in acute stroke observed in our study were in accordance with a number of reports in the literature 12-14. Kim et al. 13 found S100 protein B in 11 patients who had either large ischemic or hemorrhagic stroke. They found S100 peak on the third day in patients with large ischemic stroke and on the first day in patients with hemorrhagic stroke. Herrmann et al. 14 compared S-100 B and GFAP serum concentrations after stroke and found that release of both markers was associated with the volume of brain lesions and the neurological status at discharge from the hospital. Missler et al. 15 studied 44 patients and found good correlation between peak S-100 protein level in plasma and clinical outcome after 6 months. This was the first study to report an association between a single biochemical marker from blood in the acute phase of stroke and functional outcome of infarction. They concluded that the concentration of S-100 protein in blood during acute stroke was a useful marker of infarct size and of long-term clinical 107 Marmara Medical Journal 2004;17(3);105-108 Gülay Kenangil, et al. Relation Of Serum S-100 Protein To Infarct Size and Clinical Prognosis 7. Interestingly no elevation of serum S-100 protein was found in any of them. They all had good short and long term prognosis. 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