Morphological and functional alterations of the hypothalamic-pituitary system in brain death with long-term bodily living

The Uniform Determination of Death Act is Not Changing. Will Physicians Continue to Misdiagnose Brain Death?

Efforts to revise the Uniform Determination of Death Act in order to align law with medical practice have failed. Medical practice must now align with the law. People who are not dead under the law that defines death should not be declared dead. There is no compelling reason to continue the practice of declaring legally living persons to be dead.

The Relationship Between Manifestation of Diabetes Insipidus and Estimated Glomerular Filtration Rate in Brain Death

OBJECTIVES

Systematic reviews have revealed that up to 50% of patients with brain death have residual hypothalamic/pituitary activity based on the absence of central diabetes insipidus (DI). We hypothesized that different degrees of renal dysfunction may impact the presence of DI in patients with brain death.

DESIGN

Single-center prospective data collection.

SETTING

ICUs in a tertiary academic hospital.

PATIENTS

All adult patients declared brain dead over 12 years.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

DI was diagnosed by polyuria, low urine specific gravity, and increasing serum sodium, measured in close proximity. Renal function was assessed by the estimated glomerular filtration rate (eGFR), calculated using the simplified modification of diet in renal disease equation. Analysis was completed in 192 of 234 patients with brain death after excluding those with missing data, those younger than 18 years and those on vasopressin infusions. One hundred twenty-two patients (63.5%) developed DI and 70 patients (36.5%) did not. The proportion of DI decreased significantly with decreasing eGFR: for eGFR greater than 60 mL/min, DI was present in 77.2%; for eGFR 15-60 mL/min, DI was present in 54.5%; for eGFR 14.9-9.8 mL/min, DI was present in 32%; none of the 14 patients with eGFR less than or equal to 9.7 mL/min ever experienced DI ( p < 0.001). Using logistic regression, for every 10 mL/min decrease in eGFR, the odds of DI decreased 0.83 times (95% CI, 0.76-0.90, p < 0.001).

CONCLUSIONS

Renal dysfunction significantly impacts DI's clinical manifestation in brain death. We report that patients who experience brain death with severe renal dysfunction may not develop clinical signs of DI.

Alterations in neuroendocrine axes in brain-dead patients

PURPOSE

To identify changes in anterior pituitary gland hormone levels in brain-dead patients and alterations in free triiodothyronine (fT3), free thyroxine, cortisol, testosterone, and estradiol levels.

METHODS

Ten postmenopausal women and 22 men with brain death (BD) were included. The first blood sample for determination of hormones (pre-BD) was collected when the clinician observed the first signs of BD. The second blood sample (BD day) was drawn after BD certification.

RESULTS

Female patients exhibited lower follicle-stimulating hormone and prolactin levels pre-BD and luteinizing hormone, follicle-stimulating hormone, and prolactin levels on BD day than the age-matched controls. Male patients' sex hormone levels were similar to those of the age-matched controls, except for testosterone levels, which were low in both consecutive measurements. All gonadotropins and prolactin levels were above the tests' lower detection limits (LDLs), except for one male patient with gonadotropin levels below the LDLs of the tests. Estradiol levels in both sexes ranged from normal to elevated. FT3 levels were significantly decreased in the two measurements. Thyroid-stimulating hormone (TSH) levels were low in eight patients and all low TSH levels were above the test's LDL. The remaining patients had normal or elevated TSH levels. The median adrenocorticotropic hormone (ACTH) and cortisol levels were within normal limits. All cortisol and ACTH levels were above the tests' LDLs, except for one patient with ACTH levels below the LDL in both measurements.

CONCLUSION

This study supports the hypothesis that the anterior pituitary gland continues to function in the brain-dead state.

Revise the UDDA to Align the Law with Practice through Neuro-Respiratory Criteria

Although the Uniform Determination of Death Act (UDDA) has served as a model statute for 40 years, there is a growing recognition that the law must be updated. One issue being considered by the Uniform Law Commission's Drafting Committee to revise the UDDA is whether the text “all functions of the entire brain, including the brainstem” should be changed. Some argue that the absence of diabetes insipidus indicates that some brain functioning continues in many individuals who otherwise meet the “accepted medical standards” like the American Academy of Neurology's. The concern is that the legal criteria and the medical standards used to determine death by neurologic criteria are not aligned. We argue for the revision of the UDDA to more accurately specify legal criteria that align with the medical standards: brain injury leading to permanent loss of the capacity for consciousness, the ability to breathe spontaneously, and brainstem reflexes. We term these criteria neurorespiratory criteria and show that they are well-supported in the literature for physiologic and social reasons justifying their use in the law.

Hypothalamic function in patients diagnosed as brain dead and its practical consequences

Some patients who have been diagnosed as "dead by neurologic criteria" continue to exhibit certain brain functions, most commonly, neuroendocrine functions. In this chapter, we review the pathophysiology of brain death that can lead either to neuroendocrine failure or to preserved neuroendocrine functioning. We review the evidence on continued hypothalamic functioning in patients who have been declared "brain dead," examine potential mechanisms that would explain these findings, and discuss how these findings create additional confounds for brain death testing. We conclude by reviewing the evidence for the management of hypothalamic-pituitary failure in the setting of brain death and organ transplantation.

[Brain death criterion and organ donation: current neuroscientific perspective]

In der akademischen und öffentlichen Debatte wird der irreversible Hirnfunktionsausfall als Kriterium des Todes (Hirntodkriterium) immer wieder hinterfragt. Im vorliegenden Artikel werden 6 prototypische Thesen gegen das Hirntodkriterium diskutiert: 1) Nichtsuperiorität des Gehirns gegenüber anderen Organen, 2) Unsicherheit der Hirntoddiagnostik, 3) erhaltene Schmerzempfindung Hirntoter, 4) (spontane) sexuelle Reifung und erhaltene Reproduktionsfunktion Hirntoter, 5) Symmetrie von Hirntod und Embryonalphase, 6) Gleichsetzung des intensivmedizinisch erhaltenen Restorganismus Hirntoter mit dem lebenden Menschen.

Keine dieser Thesen hält einer kritischen Analyse stand. In Deutschland wird das Ganzhirntodkriterium angewendet. Der Hirntod geht mit dem völligen Ausfall jeglicher Empfindung, Bewusstheit, Mimik, Augen‑, Zungen- und Schlundmotorik, Willkürmotorik und Sexualfunktion einher (funktionelle „Enthauptung“). Medizinisch-technisch können andere Organe bzw. ihre Primitivsteuerung ersetzt werden, nicht aber das Gehirn. Das Gehirn, nicht der Körper, ist bestimmend für das menschliche Individuum. Die Gleichsetzung des künstlich erhaltenen Restorganismus, naturphilosophisch als lebendiges System interpretierbar, mit dem Organismus desselben lebenden Menschen wird durch die beliebige Reduzierbarkeit der Anzahl beteiligter Organe ad absurdum geführt. Der irreversible Hirnfunktionsausfall führt unausweichlich zum Herzstillstand, unbehandelt innerhalb von Minuten, unter Intensivtherapie i. d. R. innerhalb von Tagen. Auch beim Embryo/Fötus führt die Fehlanlage des gesamten Gehirns zum (vorgeburtlichen) Tod. Die in Deutschland gesetzliche Richtlinie zur Hirntodfeststellung hat eine im internationalen Vergleich hohe Diagnosesicherheit, es sind damit keine bestätigten Fehldiagnosen aufgetreten.

Role of vasopressin in current anesthetic practice

Arginine vasopressin (AVP), also known as antidiuretic hormone, is a peptide endogenously secreted by the posterior pituitary in response to hyperosmolar plasma or systemic hypoperfusion states. When administered intravenously, it causes an intense peripheral vasoconstriction through stimulation of V₁ receptors on the vascular smooth muscle. Patients in refractory shock associated with severe sepsis, cardiogenic or vasodilatory shock, or cardiopulmonary bypass have inappropriately low plasma levels of AVP (‘relative vasopressin deficiency’) and supersensitivity to exogenously-administered AVP. Low doses of AVP and its synthetic analog terlipressin can restore vasomotor tone in conditions that are resistant to catecholamines, with preservation of renal blood flow and urine output. They are also useful in the treatment of refractory arterial hypotension in patients chronically treated with renin-angiotensin system inhibitors, cardiac arrest, or bleeding esophageal varices. In the perioperative setting, they represent attractive adjunct vasopressors in advanced shock states that are unresponsive to conventional therapeutic strategies.

A Review of Thyroid Hormone Administration during Adult Donor Care

Serum concentrations of thyroid hormones tetraiodothyronine and triiodothyronine commonly are low after head injury and brain death. Thyroid hormone replacement therapy, however, is a controversial part of donor management. This article reviews publications in which thyroid hormone administration was evaluated in human donors. A classification of the “quality” of study methods used in those publications is presented as part of the data review. No publications support the routine administration of thyroid hormone for all donors. “Rescue” replacement in support of cardiac inotropic function is supported by some studies, but the experimental design of those investigations is not optimal. Thyroid hormone replacement and its dosing should be decided by organ procurement organizations as part of treatment protocols.

Hypothalamic-Pituitary Function in Brain Death: A Review

The Uniform Determination of Death Act (UDDA) states that an individual is dead when "all functions of the entire brain" have ceased irreversibly. However, it has been questioned whether some functions of the hypothalamus, particularly osmoregulation, can continue after the clinical diagnosis of brain death (BD). In order to learn whether parts of the hypothalamus can continue to function after the diagnosis of BD, we performed 2 separate systematic searches of the MEDLINE database, corresponding to the functions of the posterior and anterior pituitary. No meta-analysis is possible due to nonuniformity in the clinical literature. However, some modest generalizations can reasonably be drawn from a narrative review and from anatomic considerations that explain why these findings should be expected. We found evidence suggesting the preservation of hypothalamic function, including secretion of hypophysiotropic hormones, responsiveness to anterior pituitary stimulation, and osmoregulation, in a substantial proportion of patients declared dead by neurological criteria. We discuss several possible explanations for these findings. We conclude by suggesting that additional clinical research with strict inclusion criteria is necessary and further that a more nuanced and forthright public dialogue is needed, particularly since standard diagnostic practices and the UDDA may not be entirely in accord.

Terlipressin in brain-death donors

BACKGROUND

Metabolic management of brain-death organ donors includes correction of the hormonal perturbations that occur after cerebral death and impair circulatory function. Vasopressin is a hormone secreted by the posterior pituitary gland, which contributes to maintain systemic blood pressure by regulating urine secretion and small arteriole tonus. During brain death, the pituitary gland is damaged and hormone secretion rapidly ceases. Low-dose vasopressin increases systemic blood pressure and decreases the need for catecholamines in brain-dead organ donors but it is not available in many countries. Terlipressin is a synthetic analog of vasopressin characterized by greater selectivity for the V1 receptor than vasopressin. To date, the efficacy of terlipressin as a pressor agent in humans has been reported in a few studies.

METHOD

Pharmacology and literature about the use of terlipressin in shock and in particularly in neurogenic shock following brain death is summarized and our personal experience is reported.

RESULTS AND CONCLUSION

Terlipressin is helpful in controlling severe hypotension; its use allowed to reduce the infusion rate of norepinephrine about 50% in two of three brain-death organ donors, but there are not yet enough data to define its therapeutic range and incidence of collateral effects on the grafts.

Kidney grafts from brain dead donors: Inferior quality or opportunity for improvement?

Major improvements in immunosuppressive treatment, surgical techniques, and treatment of post-transplant complications have contributed considerably to improved outcome in renal transplantation over the past decades. Yet, these accomplishments have not led to similar improvements in transplant outcome when the results of living and deceased donors are compared. The enormous demand for donor kidneys has allowed for the increase in acceptance of suboptimal donors. The use of brain dead patients as organ donors has had a tremendous positive influence on the number of renal transplants. Unfortunately, the physiologically abnormal state of brain death has a negative effect on transplant outcome. The fact that transplanted kidneys derived from brain dead donors have a decreased viability indicates that potential grafts are already damaged before retrieval and preservation. In this review, we present an overview of the current knowledge of (patho)-physiological effects of brain death and its relevance for renal transplant outcome. In addition, several options for therapeutic intervention during brain death in the donor with the goal to improve organ viability and transplant outcome are discussed.

Postmortem stability of pituitary hormones in the human adenohypophysis

The hypophysis is embedded in the fossa at the base of skull, having important functions in the hormonal system. The present study investigated its postmortem morphological changes and the stability of adenohypopyseal hormones. The pituitaries were collected at autopsy 6 h to 20 days postmortem and were studied by histology, immunohistochemistry and electron microscopy. To avoid the influence of prolonged brain hypoxia or swelling, subjects who survived not longer than 12 h were examined. Histological changes were seen in the nucleus 6 h after death, followed by cytoplasmic changes, and the cell shapes were hardly identifiable 7 days postmortem. Electron microscopy revealed evident ultra-structural changes 6 h postmortem, involving rough endoplasmic reticulum, Golgi complexes, mitochondria, nuclei and cell membranes. However, secretory granules remained well preserved 7 days postmortem. Immunostaining showed positivities for growth hormone, prolactin, adenocorticotropic hormone, luteinizing hormone and thyroid-stimulating hormone up to 15 days after death. These findings suggest the usefulness of immunohistochemical investigation of the adenohypophysis for estimating the time of death and endocrinologic evaluation in decomposed cadavers.

What can be learned from brain-death models?

Brain death of the donor is an important risk factor influencing graft outcome. In addition to its nonspecific effects, it potentiates graft immunogenicity and increases host alloresponsiveness. Thus brain death in addition to other unspecific injuries such as organ procurement, preservation and consequences of ischemia/reperfusion injury, contributes towards the change of an inert organ to an immunological altered graft. Prior to engraftment, brain death initiates a cascade of molecular and cellular events including the release of proinflammatory mediators leading to cellular infiltrates. Those events may affect the incidence of both acute and chronic changes, developing and contributing to reduced graft survival. Consequently, strategies to reduce the immunogenicity or the pro-inflammatory status of the graft are becoming more attractive and might even help to improve organ quality and graft function.

Vasopressin serum levels in patients with severe brain lesions and in brain-dead patients

INTRODUCTION: Patients with severe brain lesions (SBL) and brain-dead patients (BD) frequently present with vasopressin (AVP) secretion disorders. OBJECTIVE: To evaluate AVP serum levels in SBL and BD patients. DESIGN: Prospective, open label, observational trial. SETTING: A general teaching hospital. METHOD: Three groups of adult subjects (age> 18y) of both sexes were included in this study: control group: 29 healthy volunteers; SBL group: 17 patients with Glasgow Coma Scale (GCS)< 8; and BD group: 11 brain-dead patients. Samples of venous blood were collected in the morning at rest from healthy volunteers and at 8 hourly intervals over a period of 24h from SBL and BD patients for AVP determinations. Concomitantly, some clinical and laboratorial variables were also recorded. RESULTS: AVP serum levels (pg/ml) were [mean (SD); median]: control [2.2(1.1); 2.0]; SBL [5.7(6.3); 2.9]; and BD [2.6(1.0); 2.8]. AVP serum levels varied greatly in SBL patients, but without statistically significant difference in relation to the other groups (p=0.06). Hypotension (p=0.02), hypernatremia (p=0.0001), serum hyperosmolarity (p=0.0001) and urinary hypoosmolarity (p=0.003) were outstanding in BD patients when compared with SBL. CONCLUSIONS: The AVP serum levels did not demonstrate significant statistical difference between the groups, only showing a greater variability in SBL patients (manifested as serum spike levels). Hypernatremia and hyperosmolarity were present in BD patients, indicating a failure of the hypothalamic-pituitary system in AVP production and release.

Extended somatic support for pregnant women after brain death

OBJECTIVE

To review case reports of pregnant women who have been supported after brain death until successful delivery of their infants. From these reports and other literature about brain death, normal physiologic changes of pregnancy, and specific needs for fetal development, recommendations were made to assist in supporting pregnant women after brain death until delivery of a mature fetus who is likely to survive.

DATA SOURCES

Personal files and experiences, MEDLINE review of case reports and publications about physiologic changes present during normal pregnancy and after brain death, and the critical needs for fetal development were included.

DATA EXTRACTION

Eleven reports of ten patients comprise the accumulated clinical experience. Hypotension, requiring fluid administration and inotropic/vasopressor therapy, occurred in all the mothers, and in six cases, was the reason for urgent delivery. The longest period of support was 107 days, from 15 to 32 wks of gestation. Two mothers also became organ donors. Recurrent infections, thermolability, and other complications common to prolonged ICU care were encountered. All infants survived. One had congenital abnormalities caused by phenytoin use by the mother. When followed, all others developed within normal growth and mental variables. These cases plus literature citations noted above were used to develop recommendations for maternal/fetal care.

CONCLUSION

Preservation of uterine/placental blood flow is the most important priority during somatic support. Imprecise autoregulation of the uterine vasculature during maternal hypoxemia or hypotension makes this goal a significant challenge. Special considerations for nutrition; medication use; cardiovascular, respiratory, or endocrine therapy; fetal monitoring; hormone replacement; and ethical concerns are discussed.

Normalization of brain death-induced injury to rat renal allografts by recombinant soluble P-selectin glycoprotein ligand

Donor brain death has been considered a significant risk factor for both early and late organ allograft dysfunction. This central injury not only evokes an upsurge of catecholamines with resultant peripheral tissue vasoconstriction and ischemia but also promotes release of hormones and inflammatory mediators that may also affect the organs directly. One of the resultant influences of these events is the rapid upregulation of the acute-phase adhesion molecules, the selectins. These initiate leukocyte adhesion to vascular endothelium and trigger subsequent cellular and molecular changes in the compromised tissues. An established F344 --> LEW rat model of chronic rejection was used to examine (1) whether the initial inflammatory events that develop within kidney allografts from brain-dead donors could be normalized using a recombinant soluble form of P-selectin glycoprotein ligand and (2) whether amelioration of these early changes would alter the inexorable progression of chronic allograft rejection. Untreated living donor controls experienced unrelenting chronic rejection over time. This complex process was accelerated in brain-dead donor kidneys. Treatment with P-selectin glycoprotein ligand prevented the early inflammatory changes in the transplanted organs and their subsequent (200 d) functional and morphologic manifestations, particularly when the soluble ligand was administered both to the donor before organ removal and to the recipient after engraftment. This strategy of using a naturally occurring selectin ligand to prevent donor-associated chronic graft dysfunction may be of special clinical interest in cadaver donor transplantation.

Brain death does not affect hepatic allograft function and survival after orthotopic transplantation in a canine model

BACKGROUND

Brain death has been shown to decrease graft function and survival in rodent models. The aim of this study was to evaluate how brain death affects graft viability in the donor and liver tolerance to cold preservation as assessed by survival in a canine transplant model.

METHODS

Beagle dogs were used for the study. Non-brain dead (BD) donors served as controls. Brain death was induced by sudden inflation of a subdural balloon catheter with continuous monitoring of arterial blood pressure and electroencephalographic activity. Sixteen hours after confirmation of brain death, liver grafts were retrieved. All livers were flushed in situ and preserved for 24 hr in cold University of Wisconsin solution before transplantation. Recipient survival rates, serum hepatic enzyme levels, coagulation, and metabolic parameters of the recipients were analyzed.

RESULTS

No significant changes were observed in serum aminotransferases (alanine and aspartate transaminases) and lactate dehydrogenase levels in the BD donor. After preservation, control (n=6) and BD livers (n=5) showed full functional recovery after transplant with 100% survival in both groups at day 7. There was no significant difference in peak serum alanine, aspartate transaminases, and lactate dehydrogenase after transplantation in recipients who received a liver from BD donor compared to control group. BD livers were functionally as capable as control livers in correcting metabolic acidosis during the first 24 hr posttransplantation. Coagulation profiles (index normalized ratio, activated partial thromboplastin time) after reperfusion were similar between groups.

CONCLUSION

In contrast to previous reports in rodent models, our study shows that brain death does not cause significant liver dysfunction in the donor before organ removal. Donor brain death and prolonged liver graft preservation do not interact significantly to impair liver function and survival after transplantation.

Brain death-related energetic failure of the donor heart becomes apparent only during storage and reperfusion: an ex vivo phosphorus-31 magnetic resonance spectroscopy study on the feline heart

BACKGROUND AND OBJECTIVE

Recently, we have shown, by using localized in vivo phosphorus-31 magnetic resonance spectroscopy (31P MRS) of the anterior left ventricular wall, that brain death (BD) is not associated with reduced myocardial energy status. In this study, we applied ex vivo 31P MRS of the entire heart to study the effects of BD on the energy status of the feline donor heart following explantation.

METHODS

We used cats (6 BD and 6 controls [C]) in a 26-hour protocol. After 2 hours of preparation, we induced BD by filling an intracranial balloon at t = 0 hour. At t = 6 hours, the hearts were arrested with St. Thomas' Hospital cardioplegic solution, explanted, and stored in the same solution at 4 degrees C in a 4.7 Tesla magnet for 17 hours. Subsequently, the hearts were reperfused in the Langendorff mode at 38 degrees C for 1 hour. The first 5-minute 31P MRS spectrum was obtained 1 hour after crossclamping the aorta; we obtained subsequent spectra every hour during storage and every 5 minutes during reperfusion. At the end, the hearts were dried and weighed. Phosphocreatine (PCr), gamma-adenosine triphosphate (gamma-ATP), inorganic phosphate (Pi), and phosphomonoesters (PME), were expressed per g dry heart weight. The intracellular pH (pH(i)) and the PCr/ATP ratio were calculated.

RESULTS

During storage, we identified a significant but similar decrease of pH(i), PCr/ATP ratio, and PCr in both groups. During reperfusion, pH(i) and PCr/ATP ratio recovered similarly in both groups, whereas the recovery of PCr in the BD group was significantly lower (p < 0.05). The Pi and PME increased in both groups during storage but to a lesser extent in the BD group (p < 0.05). This difference disappeared during reperfusion. The gamma-ATP was already significantly lower in the BD group at the onset of storage, and this remained so throughout storage and reperfusion (p < 0.05 vs C). Contractile capacity was lost in all hearts, except for 1 heart in the BD group.

CONCLUSION

Brain death-related failure of the energetic integrity of the feline donor heart becomes apparent only when using 31P MRS during ischemic preservation and subsequent reperfusion.

[Vasopressin and brain death]

Brain death results in the breakdown of effective central regulatory mechanisms of cardiocirculatory stability, even in patients with artificial mechanical ventilation, correction of electrolytic and acid-basic disorders and maximal conventional pharmacological support of the circulation. Recent evidences have shown that the fall of vasopressin levels in the blood circulation significantly influences the cardiocirculatory stability of patients with brain death, and its exogenous administration is defended by many authors for the management of multiorgan donor patients. In this brief review we analyse and discuss some experimental and clinical relevant studies about the role of vasopressin in the control of cardiocirculatory stability in brain death, and its potential usefulness in the management of multiorgan donor. We conclude that the role of vasopressin in the pathophysiology of brain death and its usefulness as a pharmacological agent in the management of multiorgan donor are not well elucidated, deserving further investigations.

Effects of explosive brain death on cytokine activation of peripheral organs in the rat

BACKGROUND

The success rate of transplanted organs from brain-dead cadaver donors is consistently inferior to that of living sources. As cadaver and living unrelated donors are equally genetically disparate with a given recipient, the difference must lie within the donor himself and/or the effects of organ preservation and storage. We have hypothesized that irreversible central nervous system injury may up-regulate proinflammatory mediators and cell surface molecules in peripheral organs to be engrafted, making them more prone to host inflammatory and immunological responses.

METHODS

Rats undergoing surgically induced acutely increased intracranial pressure (explosive brain death) were followed for 6 hr. Their peripheral tissues were examined by reverse transcriptase polymerase chain reaction and immunohistology, serum factors were assessed by enzyme-linked immunosorbent assay, and the influence of inflammatory molecules in the blood stream was determined by cross-circulation experiments with normal animals.

RESULTS

mRNA expression of both lymphocyte- and macrophage-associated products increased dramatically in all tissues. Similar factors in serum were coincidentally increased; these were shown to be active in vivo by cross-circulation with normal animals. The organs of all control groups, including animals with important ischemic injury and with hemorrhagic shock, were negative. Up-regulation of MHC class I and II antigens and the co-stimulatory molecule B7 suggests increased immunogenicity of the peripheral organs. These changes could be inhibited by: (i) administration of a recombinant soluble P-selectin glycoprotein ligand-Ig, a P- and E-selectin antagonist; and (ii) a fusion protein, cytotoxic T lymphocyte antigen 4-Ig, which blocks B7-mediated T-cell co-stimulation.

CONCLUSIONS

Activation of peripheral organs following explosive brain death may be caused by various interrelated events, including the effects of massive acute central injury, hypotension, and circulating factors. Almost complete suppression of these changes could be produced by biological agents. Such interventions, if reproducible in humans, could improve the quality of organs from "marginal" donors, broadening the criteria for donor acceptance.

Blood levels of cytokines in brain-dead patients: relationship with circulating hormones and acute-phase reactants

We hypothesized that increased levels of blood cytokines occur in brain-dead patients, and that these cytokines are responsible for some of the endocrine and/or acute-phase reactant abnormalities found in these patients. We measured blood levels of cytokines, hormones, and acute-phase reactants in 18 brain-dead potential organ donors at the moment of establishing the legal diagnosis of brain death and compared them with levels found in a control group. Although interleukin-1 beta (IL-1 beta) and tumor necrosis factor-alpha (TNF-alpha) levels were within the normal range, interleukin-6 (IL-6) levels were clearly above the normal range in all patients (median, 1,444 pg/mL; range, 75 to 11,780). In the brain-dead group, total thyroxine (tT4), free T4 (fT4), triiodothyronine (T3), thyrotropin (TSH), dehydroepiandrosterone sulfate (DHEA-S), testosterone, albumin, Zn, and osteocalcin levels were decreased, T3 resin uptake index (T3 RUI), corticotropin (ACTH), cortisol, 11-deoxycortisol (11-DOC), 17-hydroxyprogesterone (17-OHPr), aldosterone, luteinizing hormone, and follicle-stimulating hormone levels were normal, and reverse T3 (rT3), renin, and C-reactive protein (CRP) levels were increased. Multiple regression analysis demonstrated significant interrelations between IL-6 and T4, T3, testosterone, and CRP. We also studied the evolution of some of these parameters in four patients with severe head injury who finally developed brain death. IL-6 levels on admission to the intensive care unit (ICU) were above the normal limits, as in other patients with cranial trauma, but when the patients developed brain death, there was a pronounced increase in IL-6 levels.(ABSTRACT TRUNCATED AT 250 WORDS)