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Prostaglandin influence on pulmonary intravascular leukocytic aggregation during cardiopulmonary bypass
Prostaglandin influence on pulmonary intravascular leukocytic aggregation during cardiopulmonary bypass A variety of pharmacologic agents have been infused during cardiopulmonary bypass in an attempt to prevent intravascular leukocytic aggregation in the lung. To date corticosteroids have been advocated because of their ability to stabilize lysosomes. We have studied two additional agents, prostaglandin Et (PGE^) and dipyrainidole (DIPYR) and compared their effects with those of methylprednisolone sodium succinate (MPSS) and a control group. The drugs were infused into the dog during perfusion and lung biopsies obtained before, during, and at the end of 2 hours of cardiopulmonary bypass using whole blood prime of the Bentley bubble oxygenator. The biopsies were interpreted by a pathologist who was unaware of the modality of treatment. Our results indicate that PGE1 provides more protection from intravascular pulmonary leukocytic aggregation than DIPYR and MPSS.
Paul J. P. Bolanowski, M.D., James Bauer, M.D., George Machiedo, M.D., and William E. Neville, M.D., Newark, N. J. With the technical assistance of Lovone Nolan
A olymorphonuclear leukocyte aggregation in the pulmonary vasculature during cardiopulmonary bypass has been described.1'2 The lysosomal degeneration that takes place in these cells leads to a release of proteolytic enzymes with subsequent destruction of the surrounding structures. This phenomenon has been implicated as a mechanism for pulmonary insufficiency following prolonged extracorporeal perfusion. To date, methylprednisolone sodium succinate (MPSS) has been the drug of choice in preventing this aggregation and stabilizing the lysosomes. Recently prostaglandin El (Fig. 1) (PGEi) has been shown to maintain the integrity of lysosomes from the spleen, kidney, and pancreas of rats. This action is mediated by increasing levels of cyclic 3',5'adenosine monophosphate (cyclic AMP).4 This is further substantiated From the Division of Cardiothoracic Surgery, New Jersey Medical School-Martland Hospital, Newark, N. J. Supported by a grant from the Essex County Heart Association and National Institutes of Health Grant No. HL-13193-06. Received for publication June 9, 1976. Accepted for publication Sept. 3, 1976. Address for reprints: Paul J. P. Bolanowski, M.D., Division of Cardiothoracic Surgery, New Jersey Medical School-Martland Hospital, Newark, N. J. 07107.
by the fact that cyclic AMP inhibits the release of lysosomal enzyme from polymorphonuclear leukocytes.5 The experiment was designed to compare the effect of PGE! with other pharmacologic agents in inhibiting the aggregation of leukocytes in the pulmonary circulation. Material and methods Thirty-eight mongrel dogs, weighing approximately 15 kilograms each, were anesthesized with 15 mg. per kilogram of pentobarbital. Before being placed on partial cardiopulmonary bypass using whole blood prime of the Bently Bubble oxygenator, the animal received 3 mg. per kilogram of porcine gut heparin. No blood filters were used. The dogs were divided into four groups. Group I received no pharmacologic intervention, Group 2 received 30 mg. per kilogram of MPSS, Group 3 received 1 fig per kilogram per minute of PGEj, and Group 4 received 10 mg. per kilogram of dipyramidole (DIPYR). The drugs were infused into the dog during perfusion and lung biopsies from the midsagittal plane obtained before, during, and at the end of 2 hours of bypass. The biopsies were interpreted by a pathologist, who was unaware of the modality of treatment, and reported as 0-4 depending on the number of aggregates per low-power field. 221
The Journal of Thoracic and Cardiovascular Surgery
2 2 2 Bolanowski et al.
\
.
/ CH
.CH2 \
^ CH2
^CH2 \
/ CH 2
.CH 2 \
CH 2
^COOH ^
CH 2 XH OH
CH
S CH
CH
'CH 2 CH I OH
^CH2 CH 2
^CH3 N
CH2
Fig. 1. Structural formula of PGEL which is one of a group of unsaturated fatty acids having diversified pharmacological activity. %
' A
^
/
^
\
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*" nf" ' ~"^\
Fig. 2. Low-power view of a control animal showing aggregates of white blood cells in the pulmonary vasculature. Results The results are shown in Table I. Severity was determined by the mean severity index of all dogs showing aggregation. After 60 minutes on bypass, the control, MPSS, and DIPYR groups showed aggregation (Figs. 2 and 3), whereas the PGEX group did not (Fig. 4). All groups after 120 minutes showed aggregation; however, the PGEj group had the least number. There was no significant difference in severity among the groups. Discussion Postperfusion pulmonary insufficiency continues to be a problem in some patients despite the use of blood filters, hemodilution, and MPSS. This is especially true
if the pump time is over 1 hour. The resulting increased blood trauma, as indicated by elevated plasma hemoglobin, is due to the pump heads, cardiotomy suction, bubble oxygenator, and stored bank blood used in emergencies. One of the major pathologic lesions resulting in decreased oxygenation has been the mechanical obstruction of the pulmonary microcirculation by aggregates of platelets and leukocytes. Daly and associates,1 in 1954 and Neville and his associates2 in 1963 demonstrated an increase of polymorphonuclear leukocytes in the alveolar vascular bed following perfusion of both animals and human beings. Janoff6 and Weissmann7 and their co-workers showed that these cells are capable of releasing lysosomes containing po-
Volume 73 Number 2 February, 1977
Pulmonary intravascular
223
leukocytic aggregation
Fig. 3. High-power view showing complete obstruction of the smaller vessels by leukocytes.
Fig. 4. Low-power view of a dog's lung treated with PGE, showing no aggregates after 1 hour on bypass. Table I. Results Prebypass
120 min. bypass
60 min. bypass
Group
No. exp.
% with aggreg.
Severity
% with aggreg.
Severity
Control MPSS PGE, DIPYR
10 10 10 8
10 0 0 0
1 0 0 0
40 50 0 37
2.3 1.8 0 1.0
with aggreg. 60 60 20 37
Severity 2.3 1.3 1.5 1.3
2 24
Bolanowski
et al.
tent proteolytic and hydrolytic enzymes in the presence of hypoxia and acidosis. Once released, these enzymes can destroy surrounding structures, resulting in pulmonary dysfunction. Methylprednisolone sodium succinate was shown by Wilson 3 to prevent the adherence of white blood cells to the endothelium of pulmonary vessels of animals in shock. Also, stabilization of lysosomes by MPSS has been demonstrated by several investigators. 8, 9 This pharmacologic agent was shown to preserve pulmonary architecture and function of patients on bypass. 10 The data presented herein show that PGEj is superior to the other agents in the prevention of leukocyte aggregation in the canine lung. However, when aggregation occurs there is little difference between drugs in their ability to ameliorate this phenomenon. The effects of this agent on the ultrastructure of leukocytes and the lung during cardiopulmonary bypass are presently being studied in our laboratory. The value of PGEj in human subjects has yet to be determined.
REFERENCES 1 Daly, J. deB., Eggleton, F., Heb, C. O., Linzell, J., and Trowell, O. A.: Observations on the Perfused Living Animal (Dog) Using Homologous and Heterologous Blood, J. Exp. Physiol. 39: 29, 1954. 2 Neville, W. E., Kontaxis, A. ,Gavin, T., and Clowes, G. H. A., Jr.: Postperfusion Pulmonary Vasculitis, Arch. Surg. 82: 126, 1963.
The Journal of Thoracic and Cardiovascular Surgery
3 Wilson, J. W.: Treatment or Prevention of Pulmonary Cellular Damage with Pharmacologic Doses of Corticosteroids, Surg. Gynecol. Obstet. 134: 671, 1972. 4 Ignarro, L. J., Oronsky, A. L., and Perper, R. J.: Effects of Prostaglandins on Release of Enzymes From Lysosomes of Pancreas, Spleen and Kidney Cortex, Life Sci. 12: 195, 1973. 5 Ignarro, L. J., and Colombo, C : Enzyme Release from Polymorphonuclear Leukocyte Lysosomes, Regulation by Autonomic Drugs and Cyclic Nucleotides, Science 160: 1181, 1973. 6 Janoff, A., Weissmann, G., Zweifach, W., and Thomas, L.: Pathogenesis of Experimental Shock, Studies on Lysosomes in Normal and Tolerant Animals Subjected to Lethal Trauma and Endotoxemia, J. Exp. Med. 116:451, 1962. 7 Weissmann, G., and Thomas, L.: Studies on Lysosomes, the Effects of Endotoxin, Endotoxin Tolerance and Cortisone on the Release of Acid Hydrolases from a Granular Fraction of Rabbit Liver, J. Exp. Med. 116: 433, 1962. 8 DeDune, C : Injury, Inflammation and Immunity, Baltimore, 1964, The Williams & Wilkins Company, pp. 283-311. 9 Replogle, R. L., Gazzaniga, A. B., and Gross, R. E.: Use of Corticosteroids During Cardiopulmonary Bypass: Possible Lysosome Stabilization, Circulation 33(Suppl. I): 86, 1966. 10 Wilson, J. W., Young, W. G., Jr., and Miller, B. J.: Pulmonary Cellular Changes Prevented or Altered by Methylprednisolone Sodium Succinate, Fed. Proc. 30: 686, 1971.
Paul J. P. Bolanowski, M.D., James Bauer, M.D., George Machiedo, M.D., and William E. Neville, M.D., Newark, N. J. With the technical assistance of Lovone Nolan
A olymorphonuclear leukocyte aggregation in the pulmonary vasculature during cardiopulmonary bypass has been described.1'2 The lysosomal degeneration that takes place in these cells leads to a release of proteolytic enzymes with subsequent destruction of the surrounding structures. This phenomenon has been implicated as a mechanism for pulmonary insufficiency following prolonged extracorporeal perfusion. To date, methylprednisolone sodium succinate (MPSS) has been the drug of choice in preventing this aggregation and stabilizing the lysosomes. Recently prostaglandin El (Fig. 1) (PGEi) has been shown to maintain the integrity of lysosomes from the spleen, kidney, and pancreas of rats. This action is mediated by increasing levels of cyclic 3',5'adenosine monophosphate (cyclic AMP).4 This is further substantiated From the Division of Cardiothoracic Surgery, New Jersey Medical School-Martland Hospital, Newark, N. J. Supported by a grant from the Essex County Heart Association and National Institutes of Health Grant No. HL-13193-06. Received for publication June 9, 1976. Accepted for publication Sept. 3, 1976. Address for reprints: Paul J. P. Bolanowski, M.D., Division of Cardiothoracic Surgery, New Jersey Medical School-Martland Hospital, Newark, N. J. 07107.
by the fact that cyclic AMP inhibits the release of lysosomal enzyme from polymorphonuclear leukocytes.5 The experiment was designed to compare the effect of PGE! with other pharmacologic agents in inhibiting the aggregation of leukocytes in the pulmonary circulation. Material and methods Thirty-eight mongrel dogs, weighing approximately 15 kilograms each, were anesthesized with 15 mg. per kilogram of pentobarbital. Before being placed on partial cardiopulmonary bypass using whole blood prime of the Bently Bubble oxygenator, the animal received 3 mg. per kilogram of porcine gut heparin. No blood filters were used. The dogs were divided into four groups. Group I received no pharmacologic intervention, Group 2 received 30 mg. per kilogram of MPSS, Group 3 received 1 fig per kilogram per minute of PGEj, and Group 4 received 10 mg. per kilogram of dipyramidole (DIPYR). The drugs were infused into the dog during perfusion and lung biopsies from the midsagittal plane obtained before, during, and at the end of 2 hours of bypass. The biopsies were interpreted by a pathologist, who was unaware of the modality of treatment, and reported as 0-4 depending on the number of aggregates per low-power field. 221
The Journal of Thoracic and Cardiovascular Surgery
2 2 2 Bolanowski et al.
\
.
/ CH
.CH2 \
^ CH2
^CH2 \
/ CH 2
.CH 2 \
CH 2
^COOH ^
CH 2 XH OH
CH
S CH
CH
'CH 2 CH I OH
^CH2 CH 2
^CH3 N
CH2
Fig. 1. Structural formula of PGEL which is one of a group of unsaturated fatty acids having diversified pharmacological activity. %
' A
^
/
^
\
(
*" nf" ' ~"^\
Fig. 2. Low-power view of a control animal showing aggregates of white blood cells in the pulmonary vasculature. Results The results are shown in Table I. Severity was determined by the mean severity index of all dogs showing aggregation. After 60 minutes on bypass, the control, MPSS, and DIPYR groups showed aggregation (Figs. 2 and 3), whereas the PGEX group did not (Fig. 4). All groups after 120 minutes showed aggregation; however, the PGEj group had the least number. There was no significant difference in severity among the groups. Discussion Postperfusion pulmonary insufficiency continues to be a problem in some patients despite the use of blood filters, hemodilution, and MPSS. This is especially true
if the pump time is over 1 hour. The resulting increased blood trauma, as indicated by elevated plasma hemoglobin, is due to the pump heads, cardiotomy suction, bubble oxygenator, and stored bank blood used in emergencies. One of the major pathologic lesions resulting in decreased oxygenation has been the mechanical obstruction of the pulmonary microcirculation by aggregates of platelets and leukocytes. Daly and associates,1 in 1954 and Neville and his associates2 in 1963 demonstrated an increase of polymorphonuclear leukocytes in the alveolar vascular bed following perfusion of both animals and human beings. Janoff6 and Weissmann7 and their co-workers showed that these cells are capable of releasing lysosomes containing po-
Volume 73 Number 2 February, 1977
Pulmonary intravascular
223
leukocytic aggregation
Fig. 3. High-power view showing complete obstruction of the smaller vessels by leukocytes.
Fig. 4. Low-power view of a dog's lung treated with PGE, showing no aggregates after 1 hour on bypass. Table I. Results Prebypass
120 min. bypass
60 min. bypass
Group
No. exp.
% with aggreg.
Severity
% with aggreg.
Severity
Control MPSS PGE, DIPYR
10 10 10 8
10 0 0 0
1 0 0 0
40 50 0 37
2.3 1.8 0 1.0
with aggreg. 60 60 20 37
Severity 2.3 1.3 1.5 1.3
2 24
Bolanowski
et al.
tent proteolytic and hydrolytic enzymes in the presence of hypoxia and acidosis. Once released, these enzymes can destroy surrounding structures, resulting in pulmonary dysfunction. Methylprednisolone sodium succinate was shown by Wilson 3 to prevent the adherence of white blood cells to the endothelium of pulmonary vessels of animals in shock. Also, stabilization of lysosomes by MPSS has been demonstrated by several investigators. 8, 9 This pharmacologic agent was shown to preserve pulmonary architecture and function of patients on bypass. 10 The data presented herein show that PGEj is superior to the other agents in the prevention of leukocyte aggregation in the canine lung. However, when aggregation occurs there is little difference between drugs in their ability to ameliorate this phenomenon. The effects of this agent on the ultrastructure of leukocytes and the lung during cardiopulmonary bypass are presently being studied in our laboratory. The value of PGEj in human subjects has yet to be determined.
REFERENCES 1 Daly, J. deB., Eggleton, F., Heb, C. O., Linzell, J., and Trowell, O. A.: Observations on the Perfused Living Animal (Dog) Using Homologous and Heterologous Blood, J. Exp. Physiol. 39: 29, 1954. 2 Neville, W. E., Kontaxis, A. ,Gavin, T., and Clowes, G. H. A., Jr.: Postperfusion Pulmonary Vasculitis, Arch. Surg. 82: 126, 1963.
The Journal of Thoracic and Cardiovascular Surgery
3 Wilson, J. W.: Treatment or Prevention of Pulmonary Cellular Damage with Pharmacologic Doses of Corticosteroids, Surg. Gynecol. Obstet. 134: 671, 1972. 4 Ignarro, L. J., Oronsky, A. L., and Perper, R. J.: Effects of Prostaglandins on Release of Enzymes From Lysosomes of Pancreas, Spleen and Kidney Cortex, Life Sci. 12: 195, 1973. 5 Ignarro, L. J., and Colombo, C : Enzyme Release from Polymorphonuclear Leukocyte Lysosomes, Regulation by Autonomic Drugs and Cyclic Nucleotides, Science 160: 1181, 1973. 6 Janoff, A., Weissmann, G., Zweifach, W., and Thomas, L.: Pathogenesis of Experimental Shock, Studies on Lysosomes in Normal and Tolerant Animals Subjected to Lethal Trauma and Endotoxemia, J. Exp. Med. 116:451, 1962. 7 Weissmann, G., and Thomas, L.: Studies on Lysosomes, the Effects of Endotoxin, Endotoxin Tolerance and Cortisone on the Release of Acid Hydrolases from a Granular Fraction of Rabbit Liver, J. Exp. Med. 116: 433, 1962. 8 DeDune, C : Injury, Inflammation and Immunity, Baltimore, 1964, The Williams & Wilkins Company, pp. 283-311. 9 Replogle, R. L., Gazzaniga, A. B., and Gross, R. E.: Use of Corticosteroids During Cardiopulmonary Bypass: Possible Lysosome Stabilization, Circulation 33(Suppl. I): 86, 1966. 10 Wilson, J. W., Young, W. G., Jr., and Miller, B. J.: Pulmonary Cellular Changes Prevented or Altered by Methylprednisolone Sodium Succinate, Fed. Proc. 30: 686, 1971.