The effect of intraventricular albumin in experimental brain oedema

Acta N e u r o c h i r u r g i c a

Acta Neurochir (Wien) (1997) 139:661-669

9 Springer-Verlag1997 Printed in Austria

The Effect of Intraventricular Albumin in Experimental Brain Oedema ~C. 0nal 1, F. Unal 1, M. i. Turantan I, G. Uziim 2, A. H a s a n ~ l u 4, and M. Y. Kaynar 3 Departments of ~Neurosurgery and 2Physiology, Istanbul School of Medicine, Departments of 3Neurosurgery and 4Physiology, Cerrahpa~a School of Medicine, Istanbul University, Istanbul, Turkey

Summary Therapy for vasogenic brain oedema (VBE) is still an unsolved problem. Experimental work with the aim of establishing an oncotherapeutic option is presented. VBE is performed by focal freeze injury in rats. Using a stereotactic head holder hypo- or hyperosmolar human serum albumin is administered via the intraventricular route. The goal is to enhance the migration of oedema fluid with the aid of oncotic pressures. Early and late results are obtained for each group respectively four and twenty-four hours after the infliction of cold injury. The efficacy of therapy is evaluated by cerebrospinal fluid (CSF) osmolality, cerebral water content, tissue specific gravity, and blood-brain barrier (BBB) permeability. Posttherapeutic values for CSF osmolality are obtained by cisterna magna puncture. Hyperosmolar CSF after performance of cold injury (p < 0.05) is thought to be a result of fluid accumulation in the traumatized region partially from the intraventricular space. Posttherapeutic values after hyperosmolar albumin administration have revealed iso-osmolar CSF, increase in specific gravity (p < 0.001), and decrease in BBB permeability (p < 0.05). These results are in accordance with withdrawal of oedema fluid into the ventricles which can be interpreted as a positive therapeutic effect. Late results in hyperosmolar group have disclosed a hypo-iso-osmolar CSF, persistent increase in specific gravity, and no regression. These values have shown that hyperosmolar albumin administration does not interfere with CSF circulation. Early results of hypoosmolar albumin application are discouraging. This preliminary work of a therapeutic trial on VBE may be a basis for future investigations with different dosages and time modalities.

Keywords: Brain oedema; human serum albumin; blood-brain barrier; cold injury; vasogenic brain oedema; osmolality.

t r e a t m e n t m o d a l i t i e s . The m o s t c o m m o n l y u s e d thera p e u t i c a p p r o a c h for p o s t t r a u m a t i c b r a i n o e d e m a a p r o t o t y p e for v a s o g e n i c f o r m is o s m o t i c diuresis [10]. This f o r m o f t h e r a p y is m o s t e f f e c t i v e in the p r e s e n c e o f an intact b l o o d - b r a i n b a r r i e r (BBB). T h e e f f i c a c y is also d e b a t a b l e in case o f h y p o v o l a e m i a and o l d e r p a tients [3, 10]. M o r e o v e r , acute r e n a l failure and n e p h r o g e n i c d i a b e t e s i n c i p i d u s due to r e p e a t e d doses o f m a n n i t o l - the m o s t c o m m o n l y u s e d o s m o t i c diuretic agent - are not rare [10]. U s e o f steroids as a m e m brane s t a b i l i z e r is still a m a t t e r u n d e r d i s c u s s i o n [10, 14]. B a r b i t u r a t e s and h y p e r v e n t i l a t i o n m a y be used for a l i m i t e d p e r i o d o f time. I n t r a c r a n i a l p r e s s u r e m o n i t o r i n g and c e r e b r o s p i n a l fluid ( C S F ) d r a i n a g e m a y be a c h i e v e d b y p e r f o r m i n g a v e n t r i c u l o s t o m y . C S F d r a i n a g e is an e f f e c t i v e p r o c e d u r e in d e c r e a s i n g the i n t r a c r a n i a l p r e s s u r e as w e l l as e l i m i n a t i n g the p r o - i n f l a m m a t o r y c h e m o k i n e s . In spite o f all these treatment modalities, therapy of posttraumatic brain o e d e m a i n c l u d i n g the s e c o n d a r y insults still r e m a i n as a m u l t i d i m e n s i o n a l p r o b l e m [10, 11, 27]. T h e e x p e r i m e n t a l p r o c e d u r e r e p o r t e d here is a p r e l i m i n a r y w o r k a i m e d to e v a l u a t e the results o f intrav e n t r i c u l a r a l b u m i n a d m i n i s t r a t i o n in v a s o g e n i c b r a i n o e d e m a (VBE). E f f e c t i v e results m a y be a p r o m i s i n g s u p p o r t for further studies i n v o l v i n g the i n t r a v e n t r i c ular u s a g e o f h y p e r o s m o l a r agents.

Introduction

Materials and Methods

I n e f f i c i e n t l y t r e a t e d t r a u m a t i c b r a i n o e d e m a gives rise to i n c r e a s e d i n t r a c r a n i a l p r e s s u r e w h i c h is a m a j o r c a u s e o f h i g h m o r t a l i t y and m o r b i d i t y in n e u r o s u r g e r y [3, 5, 10, 14]. This c h a l l e n g i n g fact is the m a i n m o t i v a t i o n for the search o f m o r e e f f e c t i v e

91 female Sprague-Dawley rats (DETAE, Turkey) each weighing 200-250 g were randomized into seven groups - three control and four therapy - and anaesthetized with intraperitoneal ketamine (50 mg/kg). The effect of therapy was evaluated by CSF osmolality, cerebral water content, specific gravity, and BBB permeability values.

~. Onal et al.: Intraventricular Albumin in Experimental Brain Oedema

662 t

I

CONTROL

THERAPY F

I

I

I

I

I

I

Co

CE

CL

THrAE

TNrAL

I

I

I

THoAE

TNoAI

Fig. 1. Control and therapy groups of the procedure. Co Control group only with CMP; CE control group with early CMP - four hours after the performance of cold injury; CL control group with late CMP - twenty-four hours after the performance of cold injury; THrAE the earlY evaluation group of hyperosmolar albumin therapy; THrAL the late evaluation group of hyperosmolar albumin; THoAE the early evaluation group of hypo-osmolar albumin therapy; THoAL The late evaluation group of hypo-osmolar albumin therapy

Control groups involved three subgroups: Group Co (n = 10) with just cisterna magna puncture (CMP), group CE (n = 11) with early CMP - four hours after the infliction of cold injury, and group CL (n = 12) with late CMP, twenty-four hours after the lesion performance. Therapy groups were divided into two main groups of hyperand hypo-osmolar administration. Hyperosmolar therapy group consisted of two subgroups: THrAE (n = 17) -the early evaluation group with CMP four hours after the injury and THrAL (n = 16) the late evaluation group with CMP twenty-four hours after the lesion production. The same categorization was maintained in the hypo-osmolar therapy groups; so that early and late evaluation groups, THoAE (n = 13) and THoAL (n = 12), were established. In all groups of control and therapy, the purpose for CMP was to obtain CSF. The experiment was performed in two stages. The control and therapy groups were evaluated by CSF osmolality, cerebral water content, and specific gravity values in the first stage while CSF osmolality and BBB permeability in the second one. The first stage consisted of 38 rats, five for each of the control groups and THrAL, and six for the remaining therapy groups. 39 rats were used for the second stage of the experiment; five for each control group and six for therapy groups. Only CMP was performed in 14 other rats (1 in CE, 2 in CL, 5 in THrAE, 5 in THrAL, and 1 in THoAE). All animals were free to access water and food before and after the experiments. In the preliminary trials of the groups with and without cerebral oedema, the passage of Evans blue from left lateral ventricle to cisterna magna was confirmed in sample animals decapitated one hour after the administration of 2 microliters of the solution.

Surgical Procedure Cisterna magna puncture: For control groups rats were stabilized in a smooth plane in prone position. A vertical skin incision in order to reveal atlanto-occipital junction was performed and the muscles were dissected bilaterally by microsurgical instruments. The head and the craniovertebral junction were slightly tilted anteriorly, s o that atlanto-occipital membrane could be identified. Under the operating microscope (Zeiss-Opmi 1) the cistema magna was punctured using a 29 G needle and 25-50 microliters of CSF sample was obtained. 2/0 atraumatic silk sutures were used to close the wound in a standard fashion. Craniectomy and performance of cold injury: This stage of the procedure was accomplished as described by Tominaga and Ohni-

shi [27]. In group CE, following a vertical midline skin incision, sagittal and left coronal sutures were identified. Periosteum on left parietal region was peeled away from the midline and temporal muscle was dissected to uncover the temporal bone from its attachments. A small hole using a dental drill was opened on the central part of the parietal bone which was constantly irrigated with isotonic solution to cool off throughout this process. The hole was enlarged using a mini-curved haemostat. Dura remained intact. A craniectomy of 10 • 15 mm was performed beginning from the left of midsagittal plane and extending to the temporoparietal region. Extreme care was given not to damage the sagittal sinus. Bonewax (Ethicon) and Surgicel (Ethicon) were used to stop bleeding where required. Following the exposure, a metal probe of 4 • 10 mm was used to create a standard focal freeze injury using liquid nitrogen of -70 ~ which was kept in contact with bare dura for 45 seconds. Monolayer suturing during closure was performed. CSF was obtained four hours and twenty-four hours after the cold injury in groups CE and CL, respectively, using CMP. lntt~ventricular albumin administration: A stereotactic frame (Stoelting Co. Stellar Cat. No: 51400 USA) was used for intraventricular albumin administration in therapy groups. Rats were placed so that incisor bar was 5 mm above the interaural line. After performance of craniectomy and cold injury, 2 microliters of hyperosmolar albumin solution (Human Albumin 20%, Octopharma, Switzerland; 344 mosm/L) was injected into the left lateral ventricle by a 24 G needle Hamilton syringe using the co-ordinates described by Pellegrino and Cushman [21]. The administration was established 30 minutes after the cold injury and fractions of 0.2 microliters were given in 25-second intervals. In order to prevent the reflux of the solution, the syringe was kept in place for a period of no less than 120 seconds before removal. For hypo-osmolar therapy groups the sanae procedure was repeated with an adequate solution. An original solution of 272 mosm/L (Human albumin 5%, Octapharma, Switzerland) was diluted with a ratio of 9 : 1 using bidistilled water ending up with an osmolality of 244 mosm/L. For early evaluation groups CMP was performed four hours after the injury and for late ones CSF was obtained twenty-four hours later.

Methods for Evaluation CSF osmolality: The effect of human serum albumin (HSA) on CSF osmolality was evaluated by pre- and postadministrative values of CMP. Measurements were performed on Gonotec 30 osmometer and a total of 91 samples were studied. Taking into account the minimum volume required for a reliable evaluation which was 50 microliters, and for standardization purposes 10 microliters of each sample were diluted five times and the results were multiplied by five. Cerebral water content: The early and the late evaluation groups were decapitated under ether anaesthesia twelve hours and thirty-six hours after the above-mentioned procedures. Brains were quickly removed with no additional insults. Cerebral water content of at least five animals from each group was established in order to evaluate the therapeutic effect of trials. Tissue samples from three different locations - the central and the peripheral part of the lesion on the injured hemisphere and the area symmetrical to the injury site on the undamaged hemisphere - were taken for cerebral water content measurements. Center of the lesion was defined as geometrically the middle portion of the insult and periphery as the penumbra of the lesion site beginning approximately 15 mm away from the focal injury center. Samples were taken to numbered aluminum

~. Onal et al.: Intraventricular Albumin in Experimental Brain Oedema foils with predetermined weight. The fiesh weight of each specimen was noted. The samples were heated at 105 ~ and kept in constant temperature for 48 hours. The values were calculated using the fresh and dry weights [27]. Tissue specific gravity: A gravity column prepared by a mixture of bromobenzene and kerosene was used for determination of the specific gravity of brain samples. The specific gravity of a sample was determined using potassium-sulphate as a standard. Measurements from four different locations - center and periphery of the injured zone, a distant point away from the lesion site in the injured hemisphere (parieto-occipital region was chosen for this specific procedure), and a symmetrical site to the injured zone in the undamaged hemisphere - were achieved using the specific gravimetric method. Approximately 1 cu mm samples were dropped into the gravity column and the values on the scale were noted at the end of three minutes. The values were placed into the specific gravity curve to calculate the averages [9, 27]. BBB permeability: Rats were placed supine in the second stage of the experiment. Left femoral vein was identified under the operating microscope and 1 mL of Evans blue was injected intravenously with the aid of a 29 G sterile needle. Planned procedures of cold injury, intraventricular albumin administration, and CMP were achieved in different groups. At the end of the determined periods for early and late evaluation groups, the thorax was dissected under ether anaesthesia and inserting a needle into the left ventricle, the rats were perfused by isotonic saline solution. Perfusion was continued for at least twenty minutes till clear isotonic fluid was drawn from dissected jugular veins. The brains were extracted in no more than three minutes without any additional damage. The fresh tissue samples from three different regions - the cen-

663 tral and the peripheral site of the injury and the region symmetrical to the lesion on the uninjured hemisphere - were weighted on preweighted aluminum foils, homogenized with 50% tricholoroacetic acid (TCA), centrifuged 15000 tpm for 20 minutes, and absorbence was measured at 615 nm [2].

Statistical Analysis CSF osmolality and BBB permeability values were evaluated by Mann-Whitney U and Kruskal-Wallis nonparametric ANOVA tests. Cerebral water content and specific gravity values were studied using Kruskal-Wallis nonparametric ANOVA test. All p-values < 0.05 were accepted as statistically significant.

Results Mean values and standard deviations of osmolality, cerebral water content, tissue specific gravity, and BBB permeability of control and therapy groups are s h o w n i n T a b l e 1. C o m p a r i s o n

of the CSF osmolality

values of Co and CE groups reveal a statistically significant

difference

(p < 0 . 0 5 ) .

A

more

remarkable

r e s u l t h a s b e e n o b t a i n e d in t h e c o m p a r i s o n

of osmo-

l a l i t y v a l u e s o f C E a n d T H r A E g r o u p s (p < 0 . 0 1 ) . T h e s a m e s t a t i s t i c a l d i f f e r e n c e is e x h i b i t e d b e t w e e n and THoAE Cerebral and THoAE

CE

r e s u l t s (p < 0 . 0 1 ) . water content measurements

in THrAE

groups on peripheral region of the focal

Table 1. Mean + SD Values of Related Parameters in the Experiment

Osmolality CWC Center Periphery Contralat.

Co

CE

CL

277 + 31

348 -+ 108

75.84 -+ 1.93 76.14 + 3.81

THrAE

THrAL

THoAE

THoAL

270 _+26

276 -+ 40

270 _+28

267 _+ 13

255 _+43

79.56 -+ 4.18 86.11 + 4.07 75.83 -+ 4.13

78.56 -+ 1.02 79.44 _+3.03 75.13 -+ 1.70

76.63 + 2.99 75.43 _+ 1.15 74.99 -+ 1.05

81.97 _+2.69 84.47 -+ 2.04 80.87 _+2.29

81.67 _+3.63 78.68 +. 5.40 72.42 +. 1.49

80.16 -+4.48 80.25 + 3.11 77.82 -+ 2.87

1050.4 _+0.8 1050.56 _+0.87 1051.04 +--0.82 1051.52 _+0.86

1048.8 _+0.93 1048.7 _+0.33 1049.16 _+0.29 1049.36 + 0.38

1053.64 _+0.29 1053.66_+ 0.37 1053.86_+ 0.39 1053.9 + 0.35

1050 _+0.48 1050.28 _+0.65 1050.72_+ 0.33 1050.8 _+0.4

1047.36 _+0.79 1047.56 + 0.67 1048.26 + 0.2 1048.6 + 0.21

1050.4 _+0.33 1050.56-+ 0.44 1051.1 + 0.83 1050.86 +_0.53

2.146 _+0.61 1.71 _+0.52 0.54_+0.28

1.06 _+0.37 0.68+0.1 0.44+0.2

1.08 + 0.32 1_+0.11 0.63_+0.09

0.91 + 0.33 0.85+0.15 0.44_+0.14

0.63 + 0.51 0.37-+0.08 0.26+-_0.1

0.65 + 0.15 0.12_+0.02 0.I4_+0.08

SG Center Periphery Distant Contralat.

BBB Per Center Periphery Contralat.

1053.92 _+0.33

1053.84 _+0.21

0.25 _+0.01 0.25_+0.01

Early evaluation values of hyperosmolar albumin therapy compared to the controls reveal that the high osmolality in the injured group has decreased to iso-osmolar levels after albumin administration. Posttherapy values disclose that cerebral water content has decreased, tissue specific gravity has increased and the BBB permeability is reduced. CWC Cerebral water content, SG specific gravity, BBB Per blood-brain barrier permeability.

664

C. Onal et al.: Intraventricular Albumin in Experimental Brain Oedema

Table 2. Osmolality, Cerebral Water Content, Tissue Specific Gravity, and BBB Permeability Results of Control and Therapy Groups Evaluated by Kruskal-Wallis Nonparametric Anova and Mann Whitney U-tests. Bold values show positive, values in italics show inverse effects Osmolality Co Co CE CL THrAE THrAL THoAE THoAL

CWC (periphery) CE

CL

THrAE

THrAL THoAE THoAL

< 0.05 < 0.01

CE

CL

THrAE

THrAL THoAE THoAL

< 0.001

< 0.001 < 0.001

SG (distant)

< 0.001

Co

CE

CL

THrAE THrAL THoAE THoAL < 0.001 < 0.001

< 0.001 < 0.001

< 0.001 . < 0.001

SG (contralat.) CE

CL

Co CE CL THrAE THrAL THoAE THoAL

THrAE

THrAL THoAE THoAL

< 0.001

< 0.001 < 0.001 < 0.01

< 0.01 < 0.001

BBB Per (center)

Co CE CL THrAE THrAL THoAE THoAL

THrAE THrAL THoAE THoAL

< 0.001

Co CE CL THrAE THrAL THoAE THoAL

< 0.001

Co

CL

SG (periphery)

Co CE CL THrAE THrAL THoAE THoAL

Co

CE

Co CE CL THrAE THrAL THoAE THoAL

< 0.01

SG (center) Co

CO

CE

Co Co CE CL THrAE THrAL THoAE THoAL

CE

CL

THrAE THrAL THoAE THoAL

< 0.001 < 0.001

< 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001

BBB Per (periphery) CL

THrAE

THrAL THoAE THoAL

< 0.05

< 0.05 < 0.01

< 0.01

Co Co CE CL THrAE THrAL THoAE THoAL

CE

CL

THrAE THrAL THoAE THoAL

< 0.01

< 0.01