Erythrocyte creatine as a marker of excessive erythrocyte destruction due to hypersplenism in patients with liver cirrhosis

Pretransplant hepatomegaly is linked to relapse in patients with leukemia and myelodysplastic syndrome not in remission

Hepatomegaly is an extramedullary disease (EMD) manifestation of hematological malignancy. Although EMD before allogeneic hematopoietic stem cell transplantation (allo-HCT) is a risk factor for relapse in patients not in complete remission (NonCR) patients, the significance of hepatomegaly to allo-HCT is unclear. We conducted a single-center retrospective observational study of 140 patients with acute leukemia and myelodysplastic syndrome who underwent allo-HCT at our institution from 2014 to 2019. Hepatomegaly was assessed by ultrasonography using the liver index (LI). In the univariable analysis, the LI/height ratio was significantly associated with relapse (hazard ratio [HR] per standard deviation [sd]: 1.51, 95% confidence interval [CI] 1.18-1.93, p = 0.001, sd = 13.8) in NonCR patients (n = 62), but showed no significant association in CR patients (n = 78) (HR per sd: 0.95, 95% CI 0.64-1.39, p = 0.780, sd = 8.7). In multivariable analysis, the LI/height ratio was significantly associated with relapse (HR per sd: 1.34, 95% CI 1.02-1.78, p = 0.037) after adjusting for the refined disease risk index and conditioning intensity. Interaction analysis showed a noteworthy but not statistically significant association between the LI/height ratio and CR status (p = 0.110). In conclusion, our findings suggest that the LI may be a risk factor for relapse in NonCR patients after allo-HCT.

Evaluation of recombinant human erythropoietin responsiveness by measuring erythrocyte creatine content in haemodialysis patients

Background

One of the main causes of anaemia in patients with end-stage renal disease is relative deficiency in erythropoietin production. Eythropoiesis stimulating agent (ESA), a potent haematopoietic growth factor, is used to treat anaemia in haemodialysis patients. The effect of ESA is usually assessed by haematological indices such as red blood cell count, haemoglobin concentration and haematocrit, but erythrocyte indices do not provide information of the rapid change in erythropoietic activity. As erythrocyte creatine directly assess erythropoiesis, the aim of this study was to evaluate the effect of ESA in haemodialysis patients by measuring the erythrocyte creatine content.

Methods

ESA dose was fixed 3 months prior to the enrollment and was maintained throughout the entire study period. Erythrocyte creatine was measured with haematologic indices in 83 haemodialysis patients. Haemoglobin was also measured 3 months after.

Results

ESA dose (152.4 ± 62.9 vs. 82.2 ± 45.5 units/kg/week, P = 0.0001) and erythrocyte creatine (2.07 ± 0.73 vs. 1.60 ± 0.41 μmol/gHb, p = 0.0003) were significantly higher in 27 patients with haemoglobin <10 g/dL compared to 56 patients with haemoglobin ≥10 g/dL. There was a fair correlation between ESA dose and the concentration of creatine in the erythrocytes (r = 0.55, P < 0.0001). Increase in haemoglobin (>0.1 g/dL) was observed in 37 patients, whereas haemoglobin did not increase in 46 patients. Erythrocyte creatine levels were significantly higher in those patients with an increase in haemoglobin compared to those without (2.04 ± 0.64 vs. 1.52 ± 0.39 μmol/gHb, p < 0.0001). When 8 variables (ESA dose, erythropoietin resistance index, C-reactive protein, intact parathyroid hormone, iron supplementation, presence of anaemia, erythrocyte creatine and reticulocyte) were used in the multivariate logistic analysis, erythrocyte creatine levels emerged as the most important variable associated with increase in haemoglobin (Chi-square = 6.19, P = 0.01).

Conclusion

Erythrocyte creatine, a useful marker of erythropoietic capacity, is a reliable marker to estimate ameliorative effectiveness of ESA in haemodialysis patients.

Shortened red blood cell age in patients with end-stage renal disease who were receiving haemodialysis: a cross-sectional study

Background

The causes of anaemia in patients with end-stage renal disease include a relative deficiency in erythropoietin production and complex clinical conditions. We aimed to investigate the underlying mechanisms of anaemia in patients with end-stage renal disease who were undergoing maintenance dialysis by measuring erythrocyte creatine levels.

Methods

In a cross-sectional study, we evaluated 69 patients with end-stage renal disease who were receiving haemodialysis (n = 55) or peritoneal dialysis (n = 14). Erythrocyte creatine level, a quantitative marker of mean red blood cell (RBC) age, was measured.

Results

The mean RBC age was significantly shorter in the haemodialysis group than in the peritoneal dialysis group (47.7 days vs. 59.8 days, p < 0.0001), although the haemoglobin levels were comparable between the groups. A Spearman correlation coefficient analysis revealed that shortened RBC age positively correlated with transferrin saturation (r = 0.54), ferritin level (r = 0.47), and haptoglobin level (r = 0.39) but inversely related with reticulocyte (r = − 0.36), weekly doses of erythropoiesis-stimulating agents (ESAs; r = − 0.62), erythropoietin resistance index (r = − 0.64), and intradialytic ultrafiltration rate (r = − 0.32).

Conclusions

Shortened RBC age was observed in patients who were receiving maintenance haemodialysis and was associated with iron deficiency, greater haptoglobin consumption, higher ESA requirements, and poor erythropoietin responsiveness, as well as with greater intradialytic fluid extraction.

Physiological, but not fitness, effects of two interacting haemoparasitic infections in a wild rodent

In contrast to the conditions in most laboratory studies, wild animals are routinely challenged by multiple infections simultaneously, and these infections can interact in complex ways. This means that the impact of a parasite on its host's physiology and fitness cannot be fully assessed in isolation, and requires consideration of the interactions with other co-infections. Here we examine the impact of two common blood parasites in the field vole (Microtus agrestis): Babesia microti and Bartonella spp., both of which have zoonotic potential. We collected longitudinal and cross-sectional data from four populations of individually tagged wild field voles. This included data on biometrics, life history, ectoparasite counts, presence/absence of microparasites, immune markers and, for a subset of voles, more detailed physiological and immunological measurements. This allowed us to monitor infections over time and to estimate components of survival and fecundity. We confirm, as reported previously, that B. microti has a preventative effect on infection with Bartonella spp., but that the reverse is not true. We observed gross splenomegaly following B. microti infection, and an increase in IL-10 production together with some weight loss following Bartonella spp. infection. However, these animals appeared otherwise healthy and we detected no impact of infection on survival or fecundity due to the two haemoparasite taxa. This is particularly remarkable in the case of B. microti which induces apparently drastic long-term changes to spleen sizes, but without major adverse effects. Our work sheds light on the ecologies of these important zoonotic agents, and more generally on the influence that interactions among multiple parasites have on their hosts in the wild.

Intravascular hemolysis in patients with mitral regurgitation: Evaluation by erythrocyte creatine

BACKGROUND

Intravascular hemolysis has been reported in patients with cardiac valve prostheses, but intravascular hemolysis in patients with mitral regurgitation with native valve has not been evaluated in detail. We designed a study to elucidate the impact of regurgitation flow on intravascular hemolysis in patients with primary mitral regurgitation by measuring erythrocyte creatine.

METHODS

Erythrocyte creatine was enzymatically assayed in 29 patients with moderate to severe primary mitral regurgitation and 12 age-matched healthy volunteers. The size and characteristics of mitral regurgitation were determined by color Doppler echocardiography.

RESULTS

Erythrocyte creatine was significantly higher in patients with eccentric jet (n=17, 2.64±0.77μmol/g Hb) than that of central jet (n=12, 1.68±0.13μmol/g Hb) and control subjects (1.39±0.25μmol/g Hb). Patients with eccentric jet had a significantly lower erythrocyte count and hemoglobin (385±58 x10⁴/μL and 116±19g/l) compared to those with central jet (450±47×10⁴/μL and 137±14g/l) and control subjects (433±31×10⁴/μL and 134±19g/l). There were no significant differences in age, estimated glomerular filtration rate, pulmonary artery systolic pressure, left atrial size and left ventricular end-diastolic dimension between patients with eccentric jet and central jet.

CONCLUSIONS

Intravascular hemolysis associated with subclincal anemia in patients with eccentric jet was due to the destruction of erythrocyte by collision of the eccentric jet to the atrial wall.

JOURNAL CLUB: Four-Dimensional Flow MRI-Based Splenic Flow Index for Predicting Cirrhosis-Associated Hypersplenism

OBJECTIVE

The objective of this study is to evaluate the ability of spleen volume, blood flow, and an index incorporating multiple measures to predict cirrhosis-associated hypersplenism.

MATERIALS AND METHODS

A total of 39 patients (14 women and 25 men; mean [± SD] age, 52 ± 10 years) with cirrhosis and sequelae of portal hypertension underwent 4D flow MRI and anatomic 3-T MRI performed before and after contrast administration. Unenhanced 4D flow MRI was used to assess abdominal hemodynamics, and splenic volumes were measured on T1-weighted gradient-recalled echo MRI. Relationships among demographic characteristics, blood component counts, splenic volume, arterial flow, venous flow, and the percentage of shunted portal flow were assessed in 29 consecutive patients (i.e., the derivation group), to develop a splenic flow index. This index was assessed along with splenic volume and blood flow alone in 10 additional consecutive patients (i.e., the validation group) via ROC curve analysis, to identify platelet counts of less than 50 × 10³ cells/μL, leukocyte counts of less than 3.0 × 10³ cells/μL, or both.

RESULTS

In the derivation cohort (platelet count, 129 ± 76 × 10³ cells/μL), splenic volume, arterial flow, venous flow, and the percentage of shunted portal flow were inversely correlated with platelet counts (ρ = -0.68, -0.68, -0.56, and -0.36, respectively; p < 0.05). Adding splenic volume to arterial flow and the product of venous flow and the percentage of shunted portal flow indexed to the body surface area yielded superior correlations with platelet counts, leukocyte counts, and the degree of severity of hypersplenism (ρ = -0.75, -0.48, and -0.75, respectively; p ≤ 0.001) and predicted severe hypersplenism (sensitivity, 100%; specificity, 100%) in the validation cohort (platelet count, 93 ± 71 × 10³ cells/μL).

CONCLUSION

A splenic flow index that incorporates both splenic volume and blood flow is a better indicator of hypersplenism than is splenic volume alone.

Evaluation of Intravascular Hemolysis With Erythrocyte Creatine in Patients With Aortic Stenosis

Chronic intravascular hemolysis has been identified in patients with cardiac valve prostheses, but only a few case reports have evaluated intravascular hemolysis in patients with native valvular heart disease. To detect intravascular hemolysis in patients with aortic stenosis, erythrocyte creatine was evaluated with hemodynamic indices obtained by echocardiography.Erythrocyte creatine, a marker of erythrocyte age, was assayed in 30 patients with aortic stenosis and 10 aged matched healthy volunteers. Peak flow velocity of the aortic valve was determined by continuous-wave Doppler echocardiography. Twenty of 30 patients with aortic stenosis had high erythrocyte creatine levels (> 1.8 µmol/g Hb) and erythrocyte creatine was significantly higher as compared with control subjects (1.98 ± 0.49 versus 1.52 ± 0.19 µmol/g Hb, P = 0.007). Peak transvalvular pressure gradient ranged from 46 to 142 mmHg and peak flow velocity ranged from 3.40 to 5.95 m/second. Patients with aortic stenosis had a significantly lower erythrocyte count (387 ± 40 versus 436 ± 42 × 10(4) µL, P = 0.002) and hemoglobin (119 ± 11 versus 135 ± 11 g/L, P < 0.001) as compared with control subjects. Erythrocyte creatine had a fair correlation with peak flow velocity (r = 0.55, P = 0.002).In conclusion, intravascular hemolysis due to destruction of erythrocytes was detected in patients with moderate to severe aortic stenosis and the severity of intravascular hemolysis was related to valvular flow velocity of the aortic valve.

Clinical study on the relationship between hematocytopenia and splenomegaly caused by cirrhotic portal hypertension

This clinical study was designed to evaluate the presence of hematocytopenia in patients with splenomegaly caused by non-alcoholic cirrhotic portal hypertension. For this purpose, we randomly selected 358 patients with splenomegaly caused by non-alcoholic cirrhotic portal hypertension and admitted to the clinical data in our hospital between January 1991 and June 2009. Among these 358 patients, 322 patients (90.0 %) showed hematocytopenia, including multi-hemocyte decrease in 206 patients (i.e., 89 patients with a decrease in white blood cell count (WBC) + red blood cell count (RBC) + platelets count (PLT)); 52 patients with WBC + PLT decrease; 29 patients with RBC + PLT decrease; and 36 patients with WBC + RBC decrease) and single-hemocyte decrease in 116 patients (i.e., 31 cases with single PLT decrease; 29 cases with single WBC decrease; and 56 patients with single RBC decrease). After splenectomy, 36 patients (10.0 %) with hematocytopenia presented a statistical improvement of blood cell to normal level (P < 0.05), while 32 patients did not have any change as compared to pre-operative one (P > 0.05). It has to be noted that 4 patients did not received any surgery. Hematocytopenia was not detected in all the patients with splenomegaly caused by cirrhotic portal hypertension, thus it is probably a complication of splenomegaly but not an inevitable manifestation. It was concluded that splenectomy could be an effective treatment for splenomegaly associated with hematocytopenia, but patients without hematocytopenia could choose a non-surgical alternative treatment.

Protein deficiency alters impact of intestinal nematode infection on intestinal, visceral and lymphoid organ histopathology in lactating mice

Protein deficiency impairs local and systemic immune responses toHeligmosomoides bakeriinfection but little is known about their individual and interactive impacts on tissue architecture of maternal lymphoid (thymus, spleen) and visceral (small intestine, kidney, liver, pancreas) organs during the demanding period of lactation. Using a 2×2 factorial design, pregnant CD1 mice were fed a 24% protein sufficient (PS) or a 6% protein deficient (PD) isoenergetic diet beginning on day 14 of pregnancy and were infected with 100H. bakerilarvae four times or exposed to four sham infections. On day 20 of lactation, maternal organs were examined histologically and serum analytes were assayed as indicators of organ function. The absence of villus atrophy in response to infection was associated with increased crypt depth and infiltration of mast cells and eosinophils but only in lactating dams fed adequate protein. Infection-induced lobular liver inflammation was reduced in PD dams, however, abnormalities in the kidney caused by protein deficiency were absent in infected dams. Bilirubin and creatinine were highest in PD infected mice. Infection-induced splenomegaly was not due to an increase in the lymphoid compartment of the spleen. During lactation, infection and protein deficiency have interactive effects on extra-intestinal pathologies.

Peripheral blood cell variations in cirrhotic portal hypertension patients with hypersplenism

OBJECTIVE

To explore peripheral blood cell variations in hepatic cirrhosis portal hypertension patients with hypersplenism.

METHODS

Clinical data of 322 hypersplenism patients with decreased peripheral blood cells, admitted with cirrhotic portal hypertension, was retrospectively studied over the last 17 years.

RESULTS

In 64% (206/322) of patients, more than 2 kinds of blood cell were decreased, including 89 cases of pancytopenia (43.2%), 52 cases of WBC + PLT decrease (25.2%), 29 cases of RBC + PLT decrease (14.1%), and 36 cases of WBC + RBC decrease (17.5%); in 36% (116/322) of patients, single type blood cell decrease occurred, including 31 cases of PLT decrease (26.7%), 29 cases of WBC decrease (25%) and 56 cases of RBC decrease (48.3%). Of 227 routine bone marrow examinations, bone marrow hyperplasia was observed in 118 cases (52.0%), the remainder showed no hyperplasia. For the distinct scope and extent of peripheralblood cell decreases, preoperative blood component transfusions were carried out, then treated by surgery, after whole group splenectomy, the peripheral blood cell count was significantly higher (P<0.05).

CONCLUSIONS

Of portal hypertensive patients with splenomegaly and hypersplenism, 64% have simultaneous decrease in various blood cells, 36% have decrease in single type blood cells, 52% of patients have bone marrow hyperplasia. A splenectomy can significantly increase the reduction of peripheral blood cells.

WITHDRAWN: Noninvasive predictive models of liver fibrosis in patients with chronic hepatitis B

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Long-term dynamics of hematological data and spleen volume in cirrhotic patients after liver transplantation-various dynamics depending on etiology

Background

Hypersplenism is a common complication in cirrhotic patients, and liver transplantation would be one of the effective treatments. However, detailed dynamics, especially over a long term, are not fully understood. We investigated the long-term dynamics of hematological data and spleen volumes, as well as their correlation in cirrhotic patients who underwent liver transplantation.

Patients and methods

We studied 53 cirrhotic patients who underwent liver transplantation at our institute and followed for more than 1 year. Hematological data were collected from medical records, while spleen volumes were determined by CT volumetry at 0, 1, 3, 6, 12, 24, 36, 48, 60 postoperative months (POM).

Results

(1) Platelet (Plt) and hemoglobin (Hb) levels were gradually increased up to 18 and 10 POM, respectively, in contrast with white blood cells (WBC), which remained mostly unchanged from pretransplantation levels. (2) Spleen volume was sharply decreased in the first POM, then showed a slower but steady decline up to 48 POM. (3) Spleen volume was significantly correlated with hematological data, though the levels were generally weak (Plt: r = 0.433, p < 0.001; Hb: r = 0.233, p < 0.001; WBC: r = 0.217, p = 0.001). (4) Spleen volume was strongly correlated with all hematological parameters in HBV patients (Plt: r = 0.617, p < 0.0001; Hb: r = 0.401, p < 0.001; WBC: r = 0.387, p < 0.001), in contrast with that in other etiologies, which had generally weak correlations though some were statistically significant.

Conclusions

We investigated the long-term dynamics of hematological data and spleen volume in cirrhotic patients after liver transplantation. Unique dynamics and correlations between them were found among the different etiologies investigated.

Pathophysiology of sickle cell disease is mirrored by the red blood cell metabolome

Emerging metabolomic tools can now be used to establish metabolic signatures of specialized circulating hematopoietic cells in physiologic or pathologic conditions and in human hematologic diseases. To determine metabolomes of normal and sickle cell erythrocytes, we used an extraction method of erythrocytes metabolites coupled with a liquid chromatography-mass spectrometry–based metabolite profiling method. Comparison of these 2 metabolomes identified major changes in metabolites produced by (1) endogenous glycolysis characterized by accumulation of many glycolytic intermediates; (2) endogenous glutathione and ascorbate metabolisms characterized by accumulation of ascorbate metabolism intermediates, such as diketogulonic acid and decreased levels of both glutathione and glutathione disulfide; (3) membrane turnover, such as carnitine, or membrane transport characteristics, such as amino acids; and (4) exogenous arginine and NO metabolisms, such as spermine, spermidine, or citrulline. Finally, metabolomic analysis of young and old normal red blood cells indicates metabolites whose levels are directly related to sickle cell disease. These results show the relevance of metabolic profiling for the follow-up of sickle cell patients or other red blood cell diseases and pinpoint the importance of metabolomics to further depict the pathophysiology of human hematologic diseases.

Characteristics and clinical significance of hypersplenism secondary to splenomegaly caused by cirrhotic portal hypertension

The diagnosis of hypersplenism secondary to cirrhotic portal hypertension is primarily based on the presence of peripheral blood cytopenia. However, patients with cirrhotic portal hypertension-induced splenomegaly do not always develop peripheral blood cytopenia. As surgery permits eliminating massive splenomegaly/hypersplenism, improving peripheral blood cytopenia and preventing the occurrence of hemorrhage, it is indicated for the majority of patients with cirrhotic portal hypertension-induced splenomegaly. Non-surgical treatments are indicated for patients without massive splenomegaly, peripheral blood cytopenia and history of hemorrhage.

Tissue mineral distributions are differentially modified by dietary protein deficiency and a murine nematode infection

This study was designed to investigate whether mineral concentrations in the spleen, serum, and liver were modified by challenge infection with a gastrointestinal nematode, by infection dose, or by protein deficiency despite adequate dietary intakes of minerals. BALB/c mice fed protein-sufficient (PS, 24%) or protein-deficient (PD, 3%) diets were infected with 100 L3 of Heligmosomoides bakeri, drug-treated, and then re-infected with either 0, 100, or 200 L3. Protein deficiency and infection, but not dose, independently modified tissue mineral distributions. H. bakeri infection lowered serum iron concentrations in both diet groups. Despite this, PD mice had elevated iron and calcium concentrations and Ca/Zn ratio in the spleen as well as Fe/Zn ratio in liver, but they had reduced calcium, zinc, copper, and sulfur concentrations, and Cu/Zn ratio in the liver. Infection reduced calcium and iron concentrations and the Ca/Zn ratio in the spleen. We suggest that tissue mineral distribution is a consequence of Th2 immune and inflammatory responses induced by infection in PS mice and the switch to predominant Th1 inflammation in PD, nematode-infected mice.

Chronic lymphocytic leukemia cells bind and present the erythrocyte protein band 3: possible role as initiators of autoimmune hemolytic anemia

The mechanisms underlying the frequent association between chronic lymphocytic leukemia (CLL) and autoimmune hemolytic anemia are currently unclear. The erythrocyte protein band 3 (B3) is one of the most frequently targeted Ags in autoimmune hemolytic anemia. In this study, we show that CLL cells specifically recognize B3 through a still unidentified receptor. B3 interaction with CLL cells involves the recognition of its N-terminal domain and leads to its internalization. Interestingly, when binding of erythrocyte-derived vesicles as found physiologically in blood was assessed, we observed that CLL cells could only interact with inside-out vesicles, being this interaction strongly dependent on the recognition of the N-terminal portion of B3. We then examined T cell responses to B3 using circulating CLL cells as APCs. Resting B3-pulsed CLL cells were unable to induce T cell proliferation. However, when deficient costimulation was overcome by CD40 engagement, B3-pulsed CLL cells were capable of activating CD4(+) T cells in a HLA-DR-dependent fashion. Therefore, our work shows that CLL cells can specifically bind, capture, and present B3 to T cells when in an activated state, an ability that could allow the neoplastic clone to trigger the autoaggressive process against erythrocytes.

Pharmacokinetics and therapeutic effects of oltipraz after consecutive or intermittent oral administration in rats with liver cirrhosis induced by dimethylnitrosamine

Pharmacokinetics and therapeutic effects of oltipraz were evaluated after consecutive (once per day at 30 mg/kg/day for 7 and 14 days) or intermittent (once per week at 100 mg/kg/week for 1-3 weeks) oral administration to rats with liver cirrhosis induced by dimethylnitrosamine. The AUC of oltipraz was significantly greater in cirrhotic rats than controls (890 compared with 270 microg . min/mL) due to impaired liver function in cirrhotic rats. However, the AUC values after consecutive 7 (421 compared with 753 microg . min/mL) and 14 (309 compared with 821 microg . min/mL) days oral administration of oltipraz in cirrhotic rats were significantly smaller than those in respective vehicle-treated cirrhotic rats. Moreover, the AUC values after intermittent 2 and 3 weeks in cirrhotic rats were also significantly smaller than that in 1 week vehicle-treated cirrhotic rats (2370 and 1690 compared with 4760 microg . min/mL). This could be due to induction of CYP isozymes and considerably greater numbers of normal liver cells in cirrhotic rats by oral administration of oltipraz. Improved liver function by oltipraz in cirrhotic rats was proved by liver microscopy; livers are free of significant fibrosis, although evidence of bridging necrosis is still present in many rats.

Excretion and Metabolism of DA-7867, a New Oxazolidinone, in Rats

Almost negligible hepatic metabolism (minor role of liver for the metabolism) and extensive urinary and fecal excretion of DA-7867 were investigated after intravenous administration at a dose of 10 mg/kg to rats. Pharmacokinetic parameters, especially nonrenal clearances of DA-7867, were very similar between control rats and rats pretreated with SKF 525-A, a nonspecific inhibitor of CYP isozymes, in rats. Similar results were also obtained between control rats and rats with liver cirrhosis induced by dimethylnitrosamine. Hepatic first-pass effect of DA-7867 was almost negligible in rats; the areas under the plasma concentration-time curve from time zero to time infinity of DA-7867 were not significantly different between intravenous and intraportal administration. The above data indicated that liver had almost negligible metabolic activity for DA-7867 in rats. Since metabolism of DA-7867 was not considerable in rats, urinary and fecal excretion of the drug was measured for up to 14 days in ten rats. Fecal excretion was the major route for elimination of DA-7867 in rats; approximately 85.0% of intravenous dose of DA-7867 at 10 mg/kg was recovered from urine (17.0% of intravenous dose), feces (64.0% of intravenous dose), washings of the metabolic cage (3.16% of intravenous dose), and entire gastrointestinal tract (0.421% of intravenous dose).

Evaluation of Intravascular Hemolysis With Erythrocyte Creatine in Patients With Cardiac Valve Prostheses

STUDY OBJECTIVES

To detect intravascular hemolysis in patients with cardiac valve prostheses. Erythrocyte creatine, a marker of erythrocyte age that increases with shortening erythrocyte survival, was evaluated with other hemolytic markers and hemodynamic parameters.

DESIGN

Prospective study.

PATIENTS AND MEASUREMENTS

Erythrocyte creatine was enzymatically assayed in 33 patients with prosthetic valves, including 15 patients with aortic valve replacement, 13 patients with mitral valve replacement, and 5 patients with double-valve (aortic and mitral) replacement, and 33 control subjects. Blood flow velocity and valvular regurgitation were determined by Doppler echocardiography. Other hemolytic markers (lactate dehydrogenase [LDH], reticulocyte count, and haptoglobin) and cardiac muscle markers (myoglobin and myosin light chain 1) were also measured.

RESULTS

Erythrocyte creatine and LDH levels were significantly higher (p < 0.0001) and the haptoglobin level was lower (p < 0.0001) in patients with a prosthetic valve as compared with control subjects. However, there were no significant differences in these markers between those with (n = 17) and without (n = 16) regurgitation. Patients with high erythrocyte creatine levels (> 1.8 micro mol/g hemoglobin) exhibited significantly higher total peak flow velocity (sum of peak flow velocities at mitral and aortic valves) than those with normal erythrocyte creatine levels (p = 0.006). Erythrocyte creatine had a significant correlation with total peak flow velocity (r = 0.64, p < 0.0001), but LDH and haptoglobin had no significant correlation with total peak flow velocity. Patients with high LDH levels (> 460 IU/L) showed significantly higher myoglobin (p = 0.008) and myosin light chain 1 (p = 0.02) than those with normal LDH levels, whereas erythrocyte creatine was not related to cardiac muscle markers.

CONCLUSIONS

Erythrocyte creatine is a quantitative and reliable marker for intravascular hemolysis in patients with prosthetic valves. Mild hemolysis is ascribable to valvular flow velocity rather than regurgitation.

Validation of a simple liquid chromatography assay for creatine suitable for pharmacokinetic applications, determination of plasma protein binding and verification of percent labeled claim of various creatine products

Creatine has been quantified in various tissues by a range of methodologies. This paper reports on the development and validation of a simplified HPLC assay to determine plasma creatine, plasma protein binding of creatine, creatine in microdialysate and creatine in over-the-counter products. An isocratic, reversed-phase (C(18)) HPLC assay, using potassium phosphate monobasic (pH 4) as a mobile phase, was validated in human plasma and microdialysis perfusion fluid (normal saline). The lower limit of quantification for the assay was 1 mg l(-1) in saline and 5 mg l(-1) in plasma. The RSD was below 6% and accuracy was below 12% in both matrices. Protein binding in human plasma was found to be negligible (<10%). Over-the-counter creatine monohydrate products tested contained 100% creatine monohydrate. This assay was found to be suitable for pharmacokinetic studies and the assessment of plasma creatine and skeletal muscle microdialysate.

Hemoglobin metabolites mimic benzodiazepines and are possible mediators of hepatic encephalopathy

Liver failure is often accompanied by cognitive impairment and coma, a syndrome known as hepatic encephalopathy (HE). The administration of flumazenil, a benzodiazepine (BZ) antagonist, is effective in reversing the symptoms of HE in many patients. These clinical observations gave rise to notions of an endogenous BZ-like mechanism in HE, but to date no viable candidate compounds have been characterized. We show here that the hemoglobin (Hb) metabolites hemin and protoporphyrin IX (PPIX) interact with the BZ site on the gamma-aminobutyric acid (GABA(A)) receptor and enhance inhibitory synaptic transmission in a manner similar to diazepam and zolpidem. This finding suggests that hemin and PPIX are neuroactive porphyrins capable of acting as endogenous ligands for the central BZ site. The accumulation of these porphyrins under pathophysiologic conditions provides a potentially novel mechanism for the central manifestations of HE.

Evaluation of a canine model of secondary hypersplenism induced by splenic vein ligation

AIM

To introduce and evaluate a canine model of secondary hypersplenism induced by splenic vein ligation.

METHODS

Eighteen healthy mongrel dogs were randomly divided into three groups. The first group (n = 4) underwent laparotomy, the second (n = 10) and third groups (n = 4) underwent laparotomy plus ligation of splenic vein and its collateral branches to induce congestive splenomegaly. At the end of the third week, splenectomy was performed in the third group. The blood cell counts for peripheral venous blood were determined weekly, and the radiographic and histopathological changes of spleen also obtained regularly.

RESULTS

The erythrocyte and platelet counts decreased in the first week, and were significantly lowered (erythrocyte count of (6.8 ± 1.2)×10¹²/L in control vs (5.1± 0.7)×10¹²/L in second group, P<0.01; and platelet counts of (398 ± 58)×10⁹/L vs (230 ± 86)109/L, P<0.05 respectively) at the end of 3rd week after splenic vein ligation thereafter sustained. The splenomegaly, erythrocytopenia and thrombocytopenia had remained over 9 weeks. No significant changes of the leukocyte counts were observed after splenic vein ligation throughout the experiment (P>0.05). The abnormal status of erythrocytopenia and thrombocytopenia was ameliolated by splenectomy, and the erythrocyte and platelet counts were similarly to the levels of the control group in the second week after splenectomy. After the end of 3rd week after splenic vein ligation, the splenic histopathological changes conformed to the changes of chronic congestive splenomagely.

CONCLUSION

The method of splenic vein ligation to induce experimental secondary hypersplenism is simple and effective. This is a relative ideal model for surgical or interventional therapy on hypersplenism.