Introduction: Neuroglobin (Ngb) owes its name to its preferred location in the nervous system. Its plasma concentration increases during cerebral ischemia. However, the interest of its dosage in the diagnosis and the prognosis of the strokes in the adult is not defined. Objectives: To determine if plasmatic Ngb can be used as a diagnostic biomarker and prognostic for stroke in adults at the acute phase. Population and Methods: This was a prospective study in 69 people, including 39 suspected stroke (Cerebral ischemia or CI, Intracerebral hemorrhage or ICH) and 30 healthy volunteers (controls). The plasma concentration of Ngb (CmNgb in ng/ml) of the patients was determined at admission day (d1), at the third day (d3) and seventh day (d7). CmNgbtaken at d1 was compared between patients and controls. Its evolution over time, as well as its relation with the clinical parameters, including the Glasgow coma scale and the short-term mortality in stroke subjects w as analyzed by the Mann and Whitney tests and the Wilcoxon test (p < 0.05). Results: At d1, the CmNgb of all types of stroke was 3.140 ± 2.700 ng/ml, and did not differ significantly from controls (0.303 ± 0.114 ng/ml, p = 0.070). On the other hand, it was higher in CI victims (5.800 ± 0.720 ng/ml) than in ICH (1.750 ± 0,090 ng/ml) (p = 0.030). It then decreased on d3 in CI victims (2.600 ± 0.112 ng/ml) and ICH (0.420 ± 0.211 ng/ml), returning to normal on d7 (0.420 ± 0.200 ng/ml for CI’s, p = 0.001, and 0.360 ± 0.300 ng/ml for ICH, p = 0.002). There was a relationship between CmNgb, delay of occurrence of the first symptoms of the stroke (3.140 ± 2.700 ng/ml before the 6th hour, and 0.643 ± 0.244 ng/ml after the 6th hour ( p = 0.003) and the volume of the hematoma (p = 0.0027). None relationship existed between CmNgb, Glasgow coma scale (p = 0.427) and short-term mortality (CmNgb = 3.95 ng/ml in survivors versus 2.65 ng/ml in deceased p = 0.060). Conclusion: This study shows that the plasma concentration of Neuroglobin is high during stroke in humans in the acute phase. This elevation follows triphasic kinetics and appears to be more important during infarction than hemorrhage. These results suggest that CmNgb can be used as a diagnostic marker for stroke in adult at the acute phase, by differentiating ischemia from hemorrhage. However, this work needs to be confirmed on a larger sample of patients.
Neuroglobin (Ngb) is a protein discovered in 2000 by Burmester et al. [
As part of neuroprotection during acute cerebral infarction, Ngb has been widely evaluated from other vertebrates, but very little in humans [
This was a prospective study, conducted in Libreville (Gabon), from January 2016 to January 2017 included. The recruitment of people suffering from stroke (anamnesis, general examination, neurological, brain scan) was carried out in the emergency, resuscitation and neurology departments of the main university hospitals in Libreville. Volunteers (healthy people or controls), after anamnesis, general and neurological examination were selected from the general population in voluntary mode. The neuroglobin assay was done at the biochemistry laboratory of the Libreville University of Health Sciences. This investigation was conducted taking into account the principles of medical ethics according to the Helsinki Declaration [
As soon as they are hospitalized in the service, and after obtaining informed consent from the parents or the stroke subjects themselves, patients aged 18 to 65, regardless of sex, suspected of having a stroke (according to [
On the other hand, all persons having pathologies or taking drugs likely to modify the plasma concentration of neuroglobin [
Upon admitted to the different departments (resuscitation or neurology) for suspicion of stroke, the patients had a clinical examination (anamnesis, general and neurological examination) carried out by a neurologist and a resuscitator. This evaluation made it possible to look for the clinical signs in favor of a stroke [
The volunteers were recruited consecutively, by direct matching with patients, according to age and sex. Once verbal agreement obtained with each of them, an appointment was given to them in one of the pre-anesthesia consultation rooms of the University Hospital of Libreville for the clinical evaluation (Anamnesis, general and neurological examination) and the blood sample. Instead of the appointment, after signature of the consent, a single blood test was made at a peripheral vein of the forearm, in the same way as the patients. The blood, after being taken from an EDTA tube, was then sent to the Faculty of Medicine’s Biochemistry Laboratory where it was conditioned and stored using the same procedures as in patients.
In all participants, the data from the clinical and paraclinical evaluation were subsequently recorded in a medical file. In the stroke, these were epidemiological (age in year, gender, history of hypertension), clinicals (delay presumed occurrence of the first symptoms of stroke, especially, occurrence before the 6th hour, or after 6th hour following hospitalization), paraclinics (type and nature of stroke using cerebral CT, i.e. ICH, CI, SAH, volume of intracerebral hematoma measured by brain scan in two groups < 30 mm3, >30 mm3; the plasma concentration of Ngb in ng/ml and its kinetics during the first seven days of hospitalization by the determination of Ngb at d1, d3 and d7), as well as prognosis (short-term mortality by determining theoutcome on the 7th day of stroke, especially survivor and deceased; mean of Glasgow coma scale on day 1; mean of the Hemphill, WFNS, Fisher and Four scores during d1, d3 and d7) as well as prognosis (Glasgow, Hemphill, WFNS, Fisher and Four scores, established respectively at admission, d1, d3, and d7), short-term mortality (i.e. during the first 7 days of hospitalization).
The Ngb was assayed using a previously parameterized automaton (Elisys UnoTM, Human®, Germany) using the ELISA technique. To do this, an Elabscience® KIT ELISA kit was used. The assay technique used in this study was previously described in the user manual provided by Elabscience® [
This investigation used a convenience sample. The study population consisted of 69 people, including 30 controls and 39 patients. The data, upon collected, was then entered on a Microsoft Excel 2010® file and analyzed using the EPI INFO 7® software of Center for diseases control. The descriptive analysis was based on the calculation of means, medians, proportions and standard deviations. The comparison of proportions and means was based on the chi-square test. Spearman’s test allowed us to study the correlations between CmNgb and quantitative variables. The relationships between quantitative and qualitative variables were analyzed by the Mann and Whitney test and the Wilcoxon test (p < 0. 05).
Of the 69 recruited, including 39 suspected stroke and 30 controls, there were 47 men and 22 women (ratio M/W = 2.13). The epidemiological and clinical parameters, the stroke type’s, the intracerebral hematoma volume, as well as the CmNgb of the 39 persons victims for stroke are summarized in
Men accounted for 72.80% (n = 28/39), while 28.20% (n = 11/39) were women. The mean of age of the stroke population was 49 ± 12.5 years [
Types of population | |||||
---|---|---|---|---|---|
Parameters | General population | Volunteer | Stroke | CI | ICH |
Gender (Number/%) | |||||
Men | 39 (56.50) | 11 (36.60) | 28 (72) | 5 (38.40) | 18 (69.20) |
Women | 30 (43.40) | 19 (63.40) | 11 (28) | 8 (61.50) | 8 (30.70) |
Mean age ± standard deviation | 48 ± 12.00 | 40 ± 11.30 | 49 ± 15.50 | 52 ± 1.30 | 48 ± 3.80 |
History of arterial hypertension (Number/%) | |||||
Yes | 27 (39.16) | 25 (64.10) | 13 (100) | 12 (46.10) | |
No | 42 (60.87) | 14 (35.90) | 0 (0.00) | 14 (53.90) | |
Subgroups of ICH (Number/%) | |||||
ICH (Intra cerebral hematoma) | 21 (30.43) | 21 (53.84) | 0.00 | 21 (80.76) | |
SAH (Subarachnoid hemorrhage) | 5 (7.24) | 5 (12.82) | 0.00 | 5 (19.23) | |
Delay presumed occurrence of the first symptoms of stroke | |||||
Before the 6th hour | - | 23 (59) | |||
After the 6th hour | - | 16 (41) | |||
Vital Parameters (Mean ± standard deviation) | |||||
Glasgow coma scale (3 - 15) | 15 ± 1.20 | 13 ± 2.80 | 13 ± 10.1 | 11 ± 2.10 | |
Heart rate (pulse/min) | 93 ± 18.90 | 70 ± 3.50 | 110 ± 3.2 | 95 ± 13.20 | |
Sp02 (in %) | 98 ± 3.70 | 99 ± 10.10 | 98 ± 3.8 | 98 ± 20.40 | |
Systolic arterial blood pressure (mmHg) | 130 ± 20 | 191.6 ± 40 | 200 ±1.2 | 180 ± 3.20 | |
Diastolic arterial blood pressure (mmHg) | 82 ± 3.10 | 112 ± 25.30 | 120 ± 3.5 | 100 ± 5.80 | |
Specific prognostic scores for stroke (Mean ± standard deviation) | |||||
Four (0 - 16) | 15 | ||||
ICH (0 - 6) | 3 | ||||
Fisher (0 - 4) | 2 | ||||
WFNS (1 - 5) | 3 | ||||
Outcome on the 7th day of stroke (Number/%) | |||||
Survivor | 21 (53.80) | 9 | 12 | ||
Deceased | 18 (46.20) | 4 | 14 |
Parameters | Number (n) | CmNgb (ng/ml) | ±Standard Deviation of CmNgb | p |
---|---|---|---|---|
Type of population | ||||
General population | 69 | 1.400 | 1.670 | |
volunteers | 30 | 0.303 | 0.114 | 0.070 |
Stroke | 39 | 3.140 | 2.700 | |
Number of stroke subgroups (CI and ICH) | ||||
CI (Cerebral infarction) | 13 | 5.800 | 0.720 | 0.030 |
ICH (Intra cerebral hematoma) | 26 | 1.750 | 0.090 | |
Epidemiological characteristics of the working population | ||||
Gender in volunteers | ||||
Men | 19 | 1.020 | 1.810 | 0.9750 |
Women | 11 | 1.300 | 1.200 | |
Gender in stroke | ||||
Men | 28 | |||
women | 11 | |||
History of arterial hypertension in stroke | ||||
Yes | 25 | 0.9750 | ||
No | 14 | |||
Clinical parameters | ||||
Delay presumed occurrence of the first symptoms of stroke | ||||
Before the 6th hour | 23 | 3.140 | 2.700 | 0.003 |
After the 6th hour | 16 | 0.643 | 0.244 | |
Glasgow coma scale in stroke | ||||
Patient with score ≥ 3 - 13/15 | 15 | 0.427 | ||
Patient with score ≥ 13 - 15/15 | 24 | |||
Volume of intracerebral hematoma in ICH subjects | ||||
<30 mm3 | 17 | 1.21 | 0.75 | 0.0027 |
>30 mm3 | 9 | 2.16 | 0.375 | |
Outcome of stroke victims on the 7th day | ||||
Survivor | 21 | 3.95 | 0.060 | |
Deceased | 18 | 2.65 |
For vital parameters, the mean of Glasgow coma scale was 13 ± 1.20 [
From a brain scan point of view, with regard to the types of stroke, ICH’s were found in 53.90% of cases (n = 21/39), followed by CI’s with n = 13/39 (33.30%), and SAH in 12.80% of cases (n = 5/39). Moreover, in ICH patients, intracerebral hematoma volumes greater than 30 cm3 were noted in 9 patients, that is to say 42.85% (n = 9/21) (
For biological data, the mean of concentration of plasma neuroglobin (CmNgb) of the general population was 1.400 ± 1.670 ng/ml. In controls, it was 0.303 ± 0.114 ng/ml, compared to 3.140 ± 2.700 ng/ml for stroke victims of all types. Of the 21 patients who presented ICH, n = 10/21 (47.64%) had an ICH score ≥ 2/6. In CI victim’s, 76.90% (n = 10/13) had a Four score ≥ 15/16 (
The comparison of the CmNgb of stroke victims with that of the controls at admission, its evolution over time as well as its relation with the epidemiological and clinical parameters including age, sex, history of arterial hypertension, the delay in the presumed occurrence of the initial symptoms of stroke, the Glasgow coma scale as well as the prognosis in the first week of admission, and the volume of intracerebral hematoma had been studied by the Spearman, Mann-Whitney and Wilcoxon tests.
Data from this analysis show that in controls, no relationship was found between CmNgb and age (p = 0.070), sex (1.020 ± 1.810 ng/ml in men, and 1.300 ± 1.200 ng/ml in women, p = 0.975). In addition, there was no relationship between the existence of the history of arterial hypertension and CmNgb in patients (p = 0.975). At the same time, there was a relationship between CmNgb collected from admission in subjects with stroke of any type, and the delay presumed occurrence of the first symptoms of stroke, especially, occurrence before the 6th hour, or after 6th hour following hospitalization (0.643 ± 0.244 ng/ml before 6 h, against 3.140 ± 2.700 ng/ml after 6 h, p = 0.003). Regarding the comparison of CmNgb between CI and ICH at hospitalization, it was 5.805 ± 0.720 ng/ml in CI and 1.750 ± 0.090 ng/ml in ICH (p = 0.03) (
About brain imaging, there is a relationship between the CmNgb and the volume of the hematoma. In fact, CmNgb was 2.161 ± 0.375 ng/ml for hematomas with a volume greater than 30 mm3, compared with 1.210 ± 0.752 ng/ml for those with a lower volume (p = 0.0027).
There was no relationship between CmNgb, mean of Glasgow coma scale (p = 0.427) and outcome of patients during the first week of hospitalization (p = 0.06) (
The study of the kinetics of CmNgb according to the type of stroke reveals that it was higher on d1 in the subjects with CI (5.805 ± 0.720 ng/ml) than ICH (1.750 ± 0.090 ng/ml) (p = 0.003). At d3, it was 2.602 ± 0.112 ng/ml for CI and 0.420 ± 0.211 for ICH. At the 7th day of hospitalization, it was 0.420 ± 0.20 ng/ml (p = 0.001) in the victims of CI, compared to 0.360 ± 0.300 ng/ml in the ICH (p = 0.002) (
Kinetic (day) | CI CmNgb (ng/ml) Mean ± standard deviation | ICH CmNgb (ng/ml) Mean ± standard deviation | p |
---|---|---|---|
J1 | 5.800 ± 0.720 | 1.750 ± 0.090 | 0.003 |
J3 | 2.600 ± 0.600 | 0.420 ± 0.100 | 0.001 |
J7 | 0.420 ± 0.200 | 0.360 ± 0.300 | 0.002 |
The purpose of this prospective study was to evaluate the role of plasma Ngb in the initial diagnosis and short-term prognosis of adult stroke victims (infarction and hemorrhage), taking into account subgroups (CI or cerebral infarction, SHA or subarachnoid haemorrhage, ICH or intracerebral hematoma). To do this, we selected a convenience sample, consisting of stroke suspects (patients), selected consecutively over a one-year period, with direct match by age and sex to persons in good health (Volunteers). This investigation being a hospital series, we unfortunately ran into several difficulty. The most frequent were the difficulty of obtaining a brain scan (economical difficults, disponibility of imaging), before taking blood samples, the use of drugs that can modify the expression of Ngb by some clinicians [
In our series, we noted more hemorrhagic than ischemic strokes (26 versus 13). These data are similar to those obtained by Adeloye et al. [
Concerning the gender, men presented more hypertension than women. According to African studies, this result corroborates those found by several other authors [
The mean age of the stroke population in this investigation is relatively similar to that of the majority of African studies, with a peak frequency of ICH in younger people, one of the reasons of which would be early hypertension [
➢ CmNgb in the controls
Ngb is a protein whose mechanisms can explain its presence at the plasma in physiological conditions as well as the standard of concentration (reference value) are not completely defined in humans [
This study found no relationship between CmNgb and age, both in patients and controls (p = 0.07). Concerning the CmNgb and age, Sun et al. [
➢ Relationship between CmNgb and sex
Contrary at the study of Szymanski et al. [
➢ Comparison of stroke neuroglobinemia to that of controls
At the end of the present investigation, it was found that in comparison with the controls, the CmNgb of stroke victims was higher regardless of the type (ischemic or hemorrhagic) (p = 0.07). Stroke usually results from rupture (hemorrhage) or vascular obstruction (ischemia) which are responsible to the hypo infusion, hypoxia and cellular ischemia. These latter processes are themselves responsible for inflammation and cellular suffering [
➢ Comparison of CmNgb taken at day 1 between subgroups of stroke victims (CI and ICH)
Because the expression of Ngb is more important in CI’s than ICH, our data suggest the probable existence of secondary ischemia in the peri-hematoma zone during ICH’s, and thus confirm those of many authors [
➢ Comparison of CmNgb taken on admission and the presumed time of appearance to first stroke symptoms in patients
We found a statistically significant relationship between the level of Ngb taken from admission in stroke and the presumed time of appearance to the first symptoms of the disease (0.643 ng/ml before 6 h, against 3.140 ng/ml after 6 h, p = 0.003). In other terms, CmNgb varied with duration of stroke. This result is comparable to that of other authors [
➢ Relationship between volume of intracerebral hematoma and CmNgb in ICH victims
At the end of our study, we observed that the concentrations of Ngb were higher in subjects with a hematoma volume greater than 30 cm3 (p = 0.027). Thus, our results suggest that there is a direct relationship between Ngb, with ischemia of which it would be partly the consequence. Despite the fact that these data corroborate those of several other studies [
➢ Relationship between the prognostic scores of stroke and CmNgb collected on admission in stroke subjects
There was no relationship between Glasgow coma scale at the admission in stroke and the CmNgb (p = 0.427). The Glasgow coma scale assesses the level of consciousness in comatose patients, without presaging etiology [
At the same time, probably because of the size of the sample, no relationship could be analyzed between the specific gravity scores of the stroke (ICH Hemphill score for intracerebral hematoma, WFNS and Fisher scores for SAH, FOUR score for CI) and CmNgb. Thus, in the African context, a study of Ngb variation in hemorrhagic stroke involving a large sample of patients and taking into account subgroups of ICH is desirable.
➢ CmNgb and short-term mortality in stroke
It has not been found none relationship between Ngb on admission and short-term mortality (p = 0.06). However, it was noted that, although the difference was not statistically significant, patients who survived had higher plasmatic Ngb concentration compared to those who died (3.95 ng/ml versus 2.65 ng/ml). Despite the fact that current studies on Ngb are not specifically focused on mortality, some authors have found that Ngb overexpression is associated with improved ischemic injury and functional recovery in rodents [
Regarding the specific kinetics of Ngb as a function of the evolution of stroke, it was noted that the CmNgb, after an elevation phase, was reduced by half to d3 and became almost normal on d7, whatever the type of stroke. In the case of cerebral infarctions, this kinetics of Ngb was also found by Shang et al. in 2006 [
Regarding to ICH, the same triphasic kinetics was noted by Dongsheng et al. [
The present prospective study was designed to assess the role of plasma Ngb in the initial diagnosis and short-term prognosis of adult stroke victims. It emerges that, at the acute phase of a stroke, in comparison with that of controls, CmNgb increases significantly regardless of the type (ICH or CI). Moreover, this increase is greater in the case of ischemia than hemorrhage, and has a triphasic kinetics. In contrast, no relationship was found between the Glasgow coma scale, short-term mortality and CmNgb. In addition, no relationship could be analyzed between CmNgb and the usual prognostic scores of stroke subgroups. Thus, our results suggest that in human, neuroglobin plasmatic can be used as a diagnostic, but not prognostic biomarker for stroke in adults at the acute phase. However, this work needs to be confirmed on a larger sample of stroke taking into account the different subgroups.
The authors declare no conflicts of interest regarding the publication of this paper.
Nnang Essone, J.F., Allognon, C., Nkiema, R., Aubin Igombé, S.R., Nzoghe Nguema, P., Ovono Abessolo, F., Anyunzok, E. and Ngou Milama, E. (2019) Diagnostic and Prognostic Interests of Plasmatic Neuroglobin during Stroke in Adult at the Acute Phase. World Journal of Neuroscience, 9, 52-70. https://doi.org/10.4236/wjns.2019.92004