OBJECTIVE

Various retinal proteins are newly exposed to immune system in a process of tissue destructive endogenous uveitis. Some of such proteins could be autoantigens that extend the ocular inflammation in human endogenous uveitis. In this study, we aimed to investigate the possibility of such spreading of autoantigens in endogenous uveoretinitis using a proteomic approach.

METHODS

Experimental autoimmune uveoretinitis (EAU) was induced in mice by inoculation with a peptide consisting of amino acids 1-20 (GPTHLFQPSLVLDMAKVLLP) of interphotoreceptor retinoid binding protein (IRBP). Six weeks after immunization, the presence of autoantibodies against the retinal proteins in mice with EAU were examined by two-dimensional electrophoresis followed by western blotting (2D-WB). Retinal proteins targeted by the autoantibodies were identified by mass spectrometry (MS) and their autoantigenicity in patients with endogenous uveitis, such as Behcet's disease (BD, n=36), Vogt-Koyanagi-Harada disease (VKH, n=16), and sarcoidosis (n=17) were examined by enzyme-linked immunosorbent assay.

RESULTS

Six new candidate autoantigens, which were detected in mice with EAU using 2D-WD were identified by MS as beta-actin, esterase D (EsteD), tubulin beta-2, brain-type creatine kinase (BB-CK), voltage-dependent anion-selective channel protein, and aspartate aminotransferase. Among the patients with endogenous uveitis, 25% of BD and 25% of VKH patients were positive for anti-EsteD antibody, and 25% of VKH and 38.4% of sarcoidosis patients were positive for anti-BB-CK antibody.

CONCLUSIONS

Autoantibodies to EsteD and BB-CK produced in EAU-induced mice were also detected in some endogenous uveitis patients, suggesting that these proteins might be autoantigens spreading in a process of endogenous uveoretinitis.

Creatine kinase (CK-BB), neuron specific enolase (NSE), ACTH, calcitonin, serotonin and gastrin releasing peptide (GRP) were measured in serum or plasma before and immediately after initiation of treatment in patients with small cell lung cancer (SCC). Pretherapeutic elevated concentrations of CK-BB were found in 82% of extensive disease patients and in 50% of patients with local disease. NSE was raised in 72% with extensive disease versus 14% of patients with local disease. Calcitonin and ACTH were raised in 27% and 28%, respectively, in all patients without significant difference between extensive and local disease patients. Serotonin was generally overall elevated in 10% and GRP in 7% but elevations were seen only in patients with extensive disease. Out of the four most frequently elevated substances at least one marker was elevated in 80% of all the patients, including 91% in extensive stage patients and 71% in limited stage patients. Frequent initial monitoring of the substances showed an increase in the concentrations of pretherapeutic elevated CK-BB and NSE on day 1 or 2 followed by a sharp decrease within 1 week. These changes were correlated to objective clinical response determined within 4-8 weeks. The results indicate that serum CK-BB and NSE are potential markers for SCC at the time of diagnosis and that changes in the concentrations during the first course of cytostatic therapy are promising as biochemical tests for early detection of response to chemotherapy.

Osteopetrosis (OPT) refers to the consequences of generalized failure of skeletal resorption during growth. Most cases are explained by loss-of-function mutation within the genes that encode either chloride channel 7 (CLCN7) or a vacuolar proton pump subunit (TCIRG1), each compromising acid secretion by osteoclasts. Patients suffer fractures and sometimes cranial nerve entrapment and insufficient medullary space for hematopoiesis. In 1996, we reported that a high serum level of the brain isoenzyme of creatine kinase (BB-CK), the CK of osteoclasts, characterizes OPT dueamong the sclerosing bone disorders (J Clin Endocrinol Metab. 1996;11:1438). Now, we show that elevation in serum of multiple lactate dehydrogenase (LDH) isoenzymes with aspartate transaminase (AST) distinguishes autosomal dominant OPT due to loss-of-function mutation in CLCN7 [Albers-Schönberg disease (A-SD)] among these conditions. Serum total LDH and AST levels as high as 3× and 2×, respectively, the upper limits of normal for age-appropriate controls, were persistent and essentially concordant in A-SD. Serum LDH was elevated in 7 of 9 children and in the 2 adults studied with A-SD. LDH isoenzyme quantitation showed excesses of LDH-2, -3, and -4. Neither total LDH nor AST increases were found in other forms of OPT, including bisphosphonate-induced OPT, or in 41 children and 6 adults representing 20 additional sclerosing bone disorders. Serum TRACP-5b and BB-CK also were markedly elevated in A-SD. Hence, high serum levels of several enzymes characterize A-SD. Elevated serum LDH isoenzymes and AST indicate a disturbance (of uncertain clinical significance) within multiple extraosseous tissues when there is CLCN7 deficiency.

In cultured human osteoblasts estradiol-17β (E2) modulated DNA synthesis, the specific activity of creatine kinase BB (CK), 12 and 15 lipoxygenase (LO) mRNA expression and formation of 12- and 15-hydroxyeicosatetraenoic acid (HETE). We now investigate the response of human bone cell line (SaOS2) to phytoestrogens and estrogen receptors (ER)-specific agonists and antagonists. Treatment of SaSO2 with E2, 2,3-bis (4-hydroxyphenyl)-propionitrile (DPN; ERβ-specific agonist), 4,4',4″-[4-propyl-(1H)-pyrazol-1,3,5-triyl] tris-phenol (PPT; ERα-specific agonist), biochainin A (BA), daidzein (D), genistein (G) and raloxifene (Ral) showed increased DNA synthesis and CK. Ral inhibited completely all stimulations except DPN and to some extent D. The ERα-specific antagonist methyl-piperidino-pyrazole (MPP) and the ERβ-specific antagonist 4-[2-phenyl-5,7-bis (tri-fluoro-methyl) pyrazolo [1,5-a]pyrimidin-3-yl] phenol (PTHPP) inhibited DNA synthesis, CK and reactive oxygen species (ROS) formation induced by estrogens according to their receptors affinity. The LO inhibitor baicaleine inhibited only E2, DPN and G's effects. E2 and Ral unlike all other compounds had no effect on ERα mRNA expression, while ERβ mRNA expression was stimulated by all compounds. All compounds modulated the expression of 12LO and 15LO mRNA, except E2, PPT and Ral for 12LO, and 12- and 15-HETE productions and stimulated ROS formation which was inhibited by NADPH oxidase inhibitors diphenyleneiodonium chloride (DPI) and N-acetyl cysteine and the estrogen inhibitor ICI. DPI did not affect hormonal-induced DNA and CK. In conclusion, we provide evidence for the separation of mediation via ERα and ERβ pathways in the effects of estrogenic compounds on osteoblasts, but the role of LO/HETE/ROS is unclear.

An isoenzyme of creatine kinase [ATP: creatine N-phosphotransferase, EC 2.7.3.2] was isolated in pure, crystalline form from mitochondria of human heart muscle. The enzyme has a molecular weight of 84,000 and consists of two subunits with identical molecular weight, each containing two reactive sulfhydryl groups. The enzyme has a specific activity of 15 +/- 2 U/mg in the direction of creatine phosphate synthesis at optimum pH of 8.7 and of 45 +/- 5 U/mg in the direction of ATP synthesis at optimum pH of 6.7. Mitochondrial creatine kinase has Michaelis constants of 1.70 mM for MgATP2-, 8.00 mM for creatine, 0.15 mM for MgADP-, and 3.00 mM for creatine phosphate. The mitochondrial enzyme differs from the other creatine kinase isoenzymes, i.e. from muscle (CK-MM), brain (CK-BB), and their hybrid form (CK-MB) in (I) its amino acid composition and its amino terminal amino acid sequence, (II) its electrophoretic mobility, and (III) its immunological properties. It thus constitutes a fourth isoenzyme of creatine kinase. By analogy to CK-MM, CK-BB, and CK-MB, the mitochondrial isoenzyme was designated as CK-MiMi.

With a new immunoenzymometric assay we measured human glycogen phosphorylase isoenzyme BB (GPBB) in 116 healthy individuals, 14 patients with stable angina, 107 nontraumatic chest pain patients on admission to the emergency department [45 acute myocardial infarction (AMI), 49 unstable angina, 13 other diseases], and in serial samples from 41 AMI patients. GPBB was compared with creatine kinase (CK), CKMB mass, myoglobin, and cardiac troponin T. Receiver-operating characteristic plots demonstrated the significantly greater (P < or = 0.012) discriminatory power of GPBB to detect acute ischemic coronary syndromes compared with all other tested markers. GPBB was the most sensitive marker for detection of AMI during the first 4 h after onset of chest pain, and only GPBB was increased above the upper reference limit (7 micrograms/L) on admission in patients who had unstable angina at rest and reversible ST-T alterations. This and the high early sensitivity of GPBB are most likely explained by its function as a key enzyme of glycogenolysis.

Creatine kinase (CK) isoenzymes MM, MB, and BB are located primarily in the cell cytosol, and increased CKMB in plasma is the hallmark of myocardial infarction. However, whether CK is released with reversible ischemic injury remains controversial. Here, we assessed plasma CK activity--cytosolic and mitochondrial CK--in serial samples (every 10 min for 60 min, then hourly or every 4 h for 48 h) from 46 conscious dogs after transient or sustained coronary occlusion. Four dogs were sham-operated (controls); four underwent sustained coronary occlusion (96 h); and 38 underwent transient coronary occlusion (10-40 min) followed by 48 h of reperfusion. In postmortem histological examination of the dogs' hearts by light and electron microscopy, we looked for ischemia or necrosis. The presence of cell swelling and glycogen depletion was indicative of ischemia, whereas the added presence of cell disruption indicated necrosis. Coronary occlusion for>> or = 20 min consistently increased plasma mitochondrial and total CK activity and produced histologically evident myocardial necrosis. In contrast, after 10 to 15 min of coronary occlusion, 12 of 14 animals, despite extensive severe reversible ischemia, showed no increase in plasma CK; the remaining 2, which had increased plasma CK, had subendocardial necrosis. Thus, cytosolic or mitochondrial CK is released from the heart only when there has been irreversible myocardial injury-a finding with significant diagnostic and therapeutic implications.

Creatine kinase (CK) isoenzyme BB-CK is predominantly found in brain and is not normally detected in the blood. A few recent reports, however, have described BB-CK in serum from several patients with osteopetrosis (OP). To evaluate the presence and specificity of BB-CK in serum in the osteopetroses among disorders that increase skeletal mass, we quantitated total CK activity and CK isoenzymes in 15 patients representing the five major clinical forms of OP (2 infantile, 3 intermediate, 7 adult [2 type I, 5 type II], and 3 carbonic anhydrase II [CA II] deficiency cases) and in 22 patients representing 14 other types of sclerosing bone disease. All OP patients (except the two adult type I subjects) had BB-CK readily detected in their serum. Conversely, only 1 of the 22 patients with other sclerosing bone disorders had detectable BB-CK in serum (1 of 3 patients with fibrodysplasia [myositis] ossificans progressiva who had barely measurable activity). In three OP patients (one of two with the infantile form and two of five with adult, type II disease), BB-CK values were sufficiently high that serum total CK activity was elevated. In a newborn with malignant OP, both cord blood plasma and peripheral blood serum had substantial amounts of BB-CK. In three subjects (with adult type II OP), who were restudied 2-6 years later, BB-CK was still elevated in their blood. BB-CK in serum appears to distinguish the osteopetroses among the sclerosing bone disorders. Absence of serum BB-CK in adult type I disease suggests that this condition may not be a genuine form of OP. Assay of BB-CK in fetal blood could be studied as a means for prenatal diagnosis of malignant OP. Why the osteoclast failure that characterizes all true forms of OP is associated with BB-CK in the circulation is a new question for skeletal biologists.

In 15 patients without acute brain injury the concentrations of Neuron-specific Enolase (NSE), S-100 Protein (S-100), Creatine Kinase (CK), and Creatine Kinase BB isoenzyme (CK-BB) in ventricular cerebrospinal fluid (CSF) were measured immediately after lateral ventricle cannulation for diagnostic or treatment purposes. From patients who were treated with a shunt another CSF sample was obtained one week after shunt implantation by puncture of the antechamber of the valve. The CSF concentrations of NSE, S-100, CK and CK-BB after cannulation were found to be of the same order as found in patients with severe head injury, stroke or subarachnoid haemorrhage. One week after shunt implantation the concentrations of S-100, CK and CK-BB had returned to normal levels in almost all patients, while the NSE concentrations remained elevated. These findings indicate that the sampling procedure may result in contamination of CSF with NSE, S-100, CK and CK-BB and they should be taken into account in the prognostic evaluation of enzyme concentrations after brain injury.

We have developed a quantitative immunoassisted enzyme assay to screen for creatine kinase isoenzymes BB (CK-BB) and mitochondrial (CK-m) using commercial antibodies and reagents. Presence of CK-m activity was subsequently confirmed by electrophoretic separation of samples with elevated values. A prospective clinical trial was undertaken in 117 subjects: Normal (30), cirrhosis patients (30), myocardial infarction patients (30), and untreated oncology patients with metastatic malignancy (27). In 12 patients with malignancy CK-m activities were elevated; all had adenocarcinomas. No significant activity was detected in patients with other malignancies. CK-m positive tumour patients had a significantly higher mortality rate, and in two instances death was preceded by a sudden rise in CK-m activity. We suggest CK-m is a marker of adenocarcinoma and its presence in serum signifies increased mortality.

Creatine kinase MB isoenzyme was measured (using antibody inhibition) in serum of patients with exogenous intoxication, acute pancreatitis, cerebrovascular accidents, meningitis, encephalitis, skeletal muscle disease, shock, postoperative states and after coronary arteriography, cardiac catherisation of cardioversion. CK-MB activity was revealed only in sera of patients with exogenous intoxication (severity III and IV), polymyositis, scleroderma, after operation or after coronary arteriography, cardiac catherisation or cardioversion. As it is not possible to differentiate between CK-MB and CK-BB using inhibiting antibodies against CK-M subunit, CK-isoenzyme activity was determined in parallel, using precipitating antibodies. No CK-BB was found in any case. The determination of CK-MB isoenzyme after blocking of the CK-MB subunit by means of inhibiting antibodies is suitable for clinical diagnosis. The method significantly increases the value of creatine kinase measurement.

Serum levels of creatine kinase isoenzyme BB (CK-BB) were measured spectrophotometrically and by electrophoresis in 17 patients with autosomal dominant osteopetrosis (ADO) and compared with those of age- and sex-matched controls. Eight patients had ADO type 1 and nine patients had ADO type II. CK-BB was significantly increased (p less than 0.002) in type II but normal in type I compared with controls. This finding supports heterogeneity of ADO, and it may indicate a potential role for CK-BB as a marker of immature osteoclasts.

The brain isoenzyme of creatine kinase (CK BB) occurs in trace amounts in normal serum and is moderately increased in only a small number of non-oncological conditions. Although many tissues and tumors contain CK BB, we observed serum elevations only in certain carcinomas. Eleven patients with tissue-proven small cell anaplastic carcinoma (SCAC) of the lung had striking elevations of serum CK BB and no evidence of central nervous system (CNS) metastases. Significant increases were also observed in three cases of prostatic carcinoma with no apparent CNS involvement, and in one case each of adenocarcinoma and SCAC of the lung with proven CNS metastases. Three patients with SCAC of lung without distant metastases, three with SCAC of the esophagus with distant metastases but no known CNS involvement, and 17 patients with oncological conditions other than SCAC of the lung or adenocarcinoma of the prostate have failed to show elevation in serum CK BB activity. Serum CK BB may be useful as a diagnostic marker or indicator of metastases for some carcinomas.

Cytosolic creatine kinase isoenzymes MM, MB, and BB are assembled from M or B subunits which occur in different relative amounts in specific tissues. The accumulation of mRNAs encoding the M and B subunits was measured during myogenesis in culture. The relative concentration of the two mRNAs was determined by hybridization with a M-CK cDNA probe isolated previously and a B-CK cDNA probe, the cloning and characterization of which is reported here. The B-CK cDNA hybridizes specifically to a 1.6-kb mRNA found in brain and gizzard but not in adult skeletal muscle tissue. The M-CK cDNA hybridizes to a smaller mRNA 1.4-kb long which is specific to skeletal muscle. In culture, the B-CK mRNA is transiently induced and then declines to a low but detectable level.

The usefulness of tumor-associated trypsin inhibitor (TATI) in the diagnosis of various solid tumors was compared to other tumor markers occurring in serum and urine (CEA, CA19-9, CA125, CA72-4, CA50, CA15-3, CA72-4, NSE, TPA, AFP, CK-BB and ferritin). TATI was particularly well suited for the diagnosis of tumors of the pancreas, ovary, oesophagus and bladder. For tumors of these organs TATI may be considered the marker of choice. TATI was also a good marker for distinguishing between disease with or without liver metastasis in cancer of the colon and the breast.

The use of an immunohistochemical method permits the localization of creatine kinase isoenzymes MM and BB in tissue sections. Frozen sections are first incubated with the specific antiserum and secondly with the soluble antigen under investigation. The antibody fixed creatine kinase can then be visualized by the tetrazolium-salt linked histochemical reaction. In this way CK-BB was found in the smooth muscle and the mucosa of the human colon. In sections of skeletal muscle CK-MM was predominantly localized in the intermyofibrillar space. Membrane bound activity could be demonstrated in the sarcoplasmic reticulum and the surface membrane after elution of the cytoplasmic enzyme. In the human tonsilla CK-BB was localized in lymphatic and epithelial tissues, CK-MM in the muscle fibers. The isoenzyme patterns in single sections of tonsilla were in parallel determined by the immunotitration assay. The results indicate the usefulness of the combined application of histochemistry and immunotitration in serial tissue sections.

The dimeric chicken brain type isoenzyme of creatine kinase (BB-CK) was mutated by a C283S amino acid exchange in the catalytic site to produce a basically inactive dimer (B*B*-CK). The mutated enzyme showed a residual activity of about 4% compared to the wild-type, whereas substrate binding parameters were not altered. The inactivated dimer was hybridized with native dimeric muscle enzyme (MM-CK) to produce a partially inactivated MB*-CK heterodimeric hybrid and also to a his-tagged BB-CK (hBhB-CK) resulting in a partially inactive hBB*-CK homodimer. The generated hybrids were purified by chromatography. The V(max) and substrate binding parameters K(m) and K(d) were determined for both directions of the CK reaction and compared to the parameters of the wild-type enzymes (MM-, BB-, hBhB-, MB-CK). In the direction of ATP synthesis (reverse reaction), the MB*- and hBB*-CK hybrids showed a decrease of V(max) to 34% and 32%, respectively, compared to the unmodified wild-type isoform. The inactivation of a single subunit in MB*-CK led to an increase in the K(d) value resulting in an significant substrate synergism, not seen with the MB-CK wild-type enzyme. In the direction of phosphocreatine synthesis (forward reaction), the modified hybrids showed a decrease of V(max) to 50% of the wild-type enzymes and no significant alterations of the K(m) and K(d) parameters. These results strongly suggest an enzymatic cooperativity of the two subunits in the reverse reaction but independent catalytic function in the forward reaction.

OBJECTIVE

Serum creatine kinase (CK) concentrations have historically been used to investigate muscle disease and serious muscle damage, and there is a growing interest in the potential for a biochemical approach to quantifying skeletal muscle injury occurring in orthopedic surgeries and spinal injuries. The wide availability of CK measurement could foster spinal muscle injury research. However, measurement validity has never been systematically demonstrated in clinical settings. In this study, the validity of serum CK concentration elevation as an index of muscle injury was investigated using lumbar decompression surgery (LDS) as a model.

METHODS

Blood samples were obtained from 18 research volunteers drawn from the clinical population undergoing LDS. A baseline sample was taken in the preoperative waiting area. Each subject's highest CK concentration between 12 and 48 hours after surgery was used as the biochemical injury response. The surface area of muscle isolated (incision lengthxdepth) and strained by retraction was obtained for concurrent validity testing against biochemical measurement.

RESULTS

The correlation between highest total CK concentration and muscle surface area was moderate (r=0.60) and significant (P<0.01). Correlations between surface area and CK at specific time points, revealed minimal loss of association at 12 hours (r=0.57) and 24 hours (r=0.58), but weaker correlations at 6 hours (r=0.45) and 48 hours (r=0.28) after injury. Analyses for proportions of each isoenzyme making up the total CK revealed that baseline and peak CK consisted almost exclusively of skeletal muscle CK (CK-MM), with minimal representation by heart muscle (CK-MB), and brain (CK-BB).

CONCLUSIONS

The findings provide support for the validity of serum CK measurement as an index of skeletal muscle injury caused by LDS, and demonstrate that LDS provides a useful model for measurement testing and development studies.

BACKGROUND

Recently retrograde cerebral perfusion (RCP) has been advocated as an alternative to complete circulatory arrest during aortic arch surgery.

METHODS

In 19 baboons, we compared brain protection using hypothermic circulatory arrest or RCP. Animals were placed on cardiopulmonary bypass, cooled to 18 degrees C, underwent 1 hour of circulatory arrest or RCP, and were reperfused for 3 hours. Biochemical variables, cerebral blood flow (colored microsphere technique), and brain histology were assessed.

RESULTS

Release of the brain-specific ischemic marker CK-BB was similar in both groups (peak values, 123 +/- 97 U/L in the circulatory arrest group and 164 +/- 88 U/L in the RCP group; p>> 0.05), as were the arteriovenous differences in glucose uptake and lactate production (p>> 0.05). During RCP, significant brain flow could not be detected (0.5 +/- 0.5 mL.min-1 x 100 g-1). About 90% of the blood was shunted to the inferior caval vein, and an equilibrium in circulating microspheres was found between RCP inflow and caval vein outflow. Less than 1% of the RCP inflow returned to the aortic arch. Histologic signs of brain damage were minimal in both groups, although slightly more glial edema was found in the RCP group.

CONCLUSIONS

These data suggest that in nonhuman primates, retrograde cerebral perfusion does not perfuse the brain because of venovenous shunting.

OBJECTIVE

To study the efficacy of post-ischemic mild brain hypothermia lasting for different time intervals on cerebral ischemic reperfusion injury.

METHODS

Male Sprague-Dawley rats were divided into a sham-operated group, normothermia (37-38 degrees C) ischemia group and mild hypothermia (31-32 degrees C) group. The last group was subdivided into four groups: 30 minute hypothermia plus 210 minute normothermia, 60 minute hypothermia plus 180 minute nomothermia,120 minute hypothermia plus 120 minute normothermia, and 240 minute hypothermia (n=8). Global cerebral ischemia was established using the Pulsinelli four-vessel occlusion model. Brain tissue was collected following a 20 minute cerebral ischemia and 240 minute reperfusion, and was used to measure the levels of glutamate (Glu), aspartate (Asp), glycine (Gly), gamma-aminobutyric acid (GABA), dopamine (DA), norepinephrine (NE), serotonin(5-HT) and hydroxyindoleacetic acid (5-HIAA), nitrite (NO(2)), endothelin-1 (ET(1)), tumor necrosis factor alpha(TNFalpha) and interleukin-1beta (IL-1beta). Serum was collected to measure the levels of lactate dehydrogenase (LDH), aspartate aminotransferase (AST), creatine kinase (CK) and its brain band isoenzyme (CK-BB).

RESULTS

Hypothermia lasting for 60-240 minutes delayed the decrease in these amino acids, postponed the decrease in DA, NE and 5-HT and increase in hydroxyindoleacetic acid (5-HIAA), and decreased the levels of IL-1beta, TNFalpha, ET(1) and NO(2) in brain tissue. Hypothermia also decreased the levels of LDH, AST, CK and CK-BB in serum as compared to normothermia group (p<0.05 or p<0.01). Hypothermia lasting for 30 minutes delayed the decreases in these amino acids and 5-HT and increase in 5-HIAA in brain tissue (p<0.05), but failed to influence the levels of IL-1beta, TNFalpha, ET(1) and NO(2) in brain tissue and the amounts of LDH, AST, CK and CK-BB in serum as compared to normothermia ischemia group (p>0.05).

CONCLUSIONS

Post-ischemic mild brain hypothermia can significantly suppress the excessive release of amino acids, monoamine neurotransmitters and inflammation response in ischemic tissue. It can also stabilize the function of the cell membrane, which is associated with the mechanism of cerebral protection by mild hypothermia. These results suggest that mild hypothermia should be applied immediately after ischemia and last for more than 60 minutes in order to obtain neuroprotective effects.

The creatine kinase (CK) system is essential for cellular energetics in tissues or cells with high and fluctuating energy requirements. Creatine itself is known to protect cells from stress-induced injury. By using an siRNA approach to silence the CK isoenzymes in human keratinocyte HaCaT cells, expressing low levels of cytoplasmic CK and high levels of mitochondrial CK, as well as HeLa cancer cells, expressing high levels of cytoplasmic CK and low levels of mitochondrial CK, we successfully lowered the respective CK expression levels and studied the effects of either abolishing cytosolic brain-type BB-CK or ubiquitous mitochondrial uMi-CK in these cells. In both cell lines, targeting the dominant CK isoform by the respective siRNAs had the strongest effect on overall CK activity. However, irrespective of the expression level in both cell lines, inhibition of the mitochondrial CK isoform generally caused the strongest decline in cell viability and cell proliferation. These findings are congruent with electron microscopic data showing substantial alteration of mitochondrial morphology as well as mitochondrial membrane topology after targeting uMi-CK in both cell lines. Only for the rate of apoptosis, it was the least expressed CK present in each of the cell lines whose inhibition led to the highest proportion of apoptotic cells, i.e., downregulation of uMi-CK in case of HeLaS3 and BB-CK in case of HaCaT cells. We conclude from these data that a major phenotype is linked to reduction of mitochondrial CK alone or in combination with cytosolic CK, and that this effect is independent of the relative expression levels of Mi-CK in the cell type considered. The mitochondrial CK isoform appears to play the most crucial role in maintaining cell viability by stabilizing contact sites between inner and outer mitochondrial membranes and maintaining local metabolite channeling, thus avoiding transition pore opening which eventually results in activation of caspase cell-death pathways.

We report the case of a patient with persistently above-normal activity of creatine kinase (CK) in serum, a major fraction of which on electrophoresis moved as a band between the MM and MB isoenzymes and on anion-exchange column chromatography eluted in the MB fraction. Measurements in the presence of specific M or B subunit-inhibitory antibodies indicated that 93% of the activity consisted of B-isomers. From these experiments we conclude that the abnormal CK is of BB nature. Gel filtration and immunoglobulin precipitation showed that the CK-BB was complexed with IgG. Normal CK-BB, when mixed with the patient's serum, was converted to macro CK-BB. In vitro stability of 37 degrees C of the abnormal enzyme was much greater than that of normal BB and MM isoenzymes. Following this finding, we then assessed 310 sera, received for enzyme assay by the clinical laboratory, for electrophoretically abnormally migrating CK isoenzymes. Of these, five (1.6%) contained such enzymes, all being of BB nature. They were of increased molecular mass, and at least three of them were complexed with IgG.

Coronavirus disease 2019 (COVID-19) is associated with considerable morbidity and mortality. The number of confirmed cases of infection with SARS-CoV-2, the virus causing COVID-19 continues to escalate with over 70 million confirmed cases and over 1.6 million confirmed deaths. Severe-to-critical COVID-19 is associated with a dysregulated host immune response to the virus, which is thought to lead to pathogenic immune dysregulation and end-organ damage. Presently few effective treatment options are available to treat COVID-19. Leronlimab is a humanized IgG4, kappa monoclonal antibody that blocks C-C chemokine receptor type 5 (CCR5). It has been shown that in patients with severe COVID-19 treatment with leronlimab reduces elevated plasma IL-6 and chemokine ligand 5 (CCL5), and normalized CD4/CD8 ratios. We administered leronlimab to 4 critically ill COVID-19 patients in intensive care. All 4 of these patients improved clinically as measured by vasopressor support, and discontinuation of hemodialysis and mechanical ventilation. Following administration of leronlimab there was a statistically significant decrease in IL-6 observed in patient A (p=0.034) from day 0-7 and patient D (p=0.027) from day 0-14. This corresponds to restoration of the immune function as measured by CD4+/CD8+ T cell ratio. Although two of the patients went on to survive the other two subsequently died of surgical complications after an initial recovery from SARS-CoV-2 infection.

Keywords: ACE2, angiotensin-converting enzyme 2; ALT, alanine aminotransferase; ARDS, acute respiratory distress syndrome; AST, aspartate aminotransferase; Acute respiratory distress syndrome (ARDS); BID, bis in die (twice a day); CCL2, chemokine C–C motif ligand 2; CCL3, chemokine C–C motif ligand 3; CCL4, chemokine C–C motif ligand 4; CCL5, chemokine C–C motif ligand 5; CCR1, C–C chemokine receptor type 1; CCR5, C–C chemokine receptor type 5; CDC, Centers for Disease Control; CK, creatine kinase; COPD, chronic obstructive pulmonary disease; COVID-19, coronavirus disease 2019; CRP, C-reactive protein; CXCL10, chemokine C-X-C motif ligand 10; CXCL2, chemokine C-X-C motif ligand 2; Coronavirus disease 2019 (COVID-19); DPP4, dipeptidyl peptidase-4; DVT, deep vein thrombosis; EDTA, ethylenediaminetetraacetic acid; FDA, Food and Drug Administration; Fi02, fraction of inspired oxygen, IgG4; Hydroxychloroquine, HLH; Leronlimab (PRO 140); Middle East respiratory syndrome coronavirus, MIG; National Early Warning Score, NK; RO, receptor occupancy; RT–PCR, reverse transcriptase polymerase chain reaction; SARS-CoV, severe acute respiratory syndrome coronavirus; SARS-CoV-2; SARS-CoV-2, severe acute respiratory syndrome coronavirus 2; T-reg RO, regulatory T cells – receptor occupancy; TGF- α, transforming growth factor alpha; TNF-α, tumor necrosis factor alpha; TNF-β, tumor necrosis factor beta; Tregs, regulatory T cells; VEGF-A, vascular endothelial growth factor A; WBC, white blood cell; WHO, World Health Organization; eIND, emergency investigational new drug application; hemophagocytic lymphohistiocytosis, HTN; hypertension, ICU; immunoglobulin G4, HCQ; intensive care unit, IL-1β; interferon gamma, IL-6; interferon gamma-inducible protein (IP) 10 or CXCL10, LOA; interleukin 1 beta, IFN-ƴ; interleukin 6, IP-10; letter of authorization, MCP; macrophage Inflammatory Proteins 1-alpha, MIP-1β; macrophage Inflammatory Proteins 1-beta, N/A; macrophage colony stimulating factor, MDC (CCL22); macrophage colony-stimulating factor encoded by the CCL22 gene, MERS-CoV; monocyte chemoattractant protein, M-CSF; monokine induced by IFN-γ (interferon gamma), MIP-1α; natural killer, OSA; not applicable, NEWS2; obstructive sleep apnea, PDGF-AA; per os (taken by mouth), RANTES; platelet-derived growth factor AA, PDGF-AA/BB; platelet-derived growth factor AA/BB, PEEP; positive end-expiratory pressure, PNA; pulmonary nodular amyloidosis, po; regulated on activation, normal T expressed and secreted (also known as CCL5).

BACKGROUND

The brain is rich in creatine kinase-BB isoenzyme activity (CK-BB), which is not normally present in cerebrospinal fluid (CSF). Results of previous studies have shown that CK-BB can be detected in the CSF of patients with aneurysmal subarachnoid hemorrhage (SAH), but whether CK-BB levels correlate with patients' neurologic outcomes is unknown.

OBJECTIVE

To evaluate the relationship between CSF CK-BB level and outcome after SAH.

METHODS

Prospective observational cohort.

METHODS

University-affiliated tertiary care center.

METHODS

Convenience sample of 30 patients seen for cerebral aneurysm clipping.

METHODS

We sampled and assayed CSF for CK isoenzymes a median of 3 days after SAH in 27 patients, and at the time of unruptured aneurysm clipping in 3 patients.

METHODS

Without knowledge of CK results, we assigned the Glasgow Outcome Scale score early (approximately 1 week) and late (approximately 2 months) after surgery.

RESULTS

Higher CSF CK-BB levels were associated with higher Hunt and Hess grades at hospital admission (Spearman rank correlation, p = 0.69; P<.001), lower Glasgow Coma Scale scores at hospital admission (p = -0.72; P<.001), and worse early outcomes on the Glasgow Outcome Scale (p = -0.64; P<.001). For patients with a favorable early outcome (Glasgow Outcome Scale score, 3-5), all CK-BB levels were less than 40 U/L. With a cutoff value of 40 U/L, CK-BB had a sensitivity of 70% and a specificity of 100% for predicting unfavorable early outcome (Glasgow Outcome Scale score, 1-2). Having a CK-BB level greater than 40 U/L increased the chance of an unfavorable early outcome, from 33% (previous probability) to 100%, whereas a CK-BB level of 40 U/L or less decreased it to 13%. Similar findings were obtained when considering late outcomes.

CONCLUSIONS

The level of CSF CK-BB may help predict neurologic outcome after SAH.