A topical cell therapy approach for diabetic chronic ulcers: Effects of mesenchymal stromal cells associated with platelet-rich plasma

BACKGROUND

Diabetic cutaneous ulcers are subjected to several physiological and biochemical defects, which contribute to wound chronicity and therapeutic failure. Platelet-rich plasma (PRP) has been used for stimulating tissue regeneration, and mesenchymal stromal cells (MSCs) have demonstrated therapeutic properties in all phases of skin regeneration in cell therapy studies.

AIMS

The objective of this study was to evaluate the therapeutic effects related to the use of a biomembrane composed of autologous MSCs and PRP on chronic wounds of diabetic patients (pre-post pilot study).

PATIENTS/METHODS

Six diabetic patients with chronic wounds for more than 6 months were subjected to adipose tissue collection for isolation of MSCs, blood collection for PRP preparation, and topical administration of a biomembrane of MSCs and PRP on each chronic wound. The statistical difference regarding the evolution of ulcers was calculated by means of paired t test.

RESULTS

There was granulation tissue formation starting from 7 days after topical application. Total re-epithelialization occurred in 5 of the 9 lesions treated, and the mean wound healing rate (WHR) was 74.55% (±32.55%) after 90 days. No cicatricial hypertrophy or retraction was observed.

CONCLUSION

Mesenchymal stromal cells topical therapy associated with PRP is well-tolerated and able to provide a reduction in ulcer area of diabetic chronic wounds.

Assessment of inflammation based on the release of oxygen radicals by granulocytes in chronic uncontrolled asthma

OBJECTIVE

To evaluate spontaneous release of superoxide anion by peripheral blood granulocytes of atopic patients with uncontrolled asthma undergoing glucocorticoid therapy and of healthy subjects.

METHODS

We studied 32 patients, aged 6 to 18 (mean 12.04), and 29 healthy subjects as a comparative group. Patients were grouped according to the forced expiratory vital capacity in the first second. Group I, forced expiratory vital capacity in the first second of between 60 and 80%, had 19 patients, and group II, forced expiratory vital capacity in the first second = 60%, had 13 patients. Spontaneous superoxide release by granulocytes was measured by a spectrophotometer method based on superoxide dismutase, before and after oral prednisone and beclomethasone, budesonide or fluticasone inhaled therapy. Statistical analyses were performed using ANOVA, Wilcoxon and Tukey tests.

RESULTS

Comparing the superoxide anion release by granulocytes of asthmatic patients and healthy subjects, we observed a higher release by cells of the uncontrolled patient group II (p < 0.05). Evaluating the superoxide release by cells of asthmatic patients before and after steroid therapy, a significant decrease was found only in patient group I.

CONCLUSION

The impact of corticosteroids on inflammatory modulation occurred in the uncontrolled asthmatics with forced expiratory vital capacity in the first second between 60 and 80%. In those with forced expiratory vital capacity in the first second of = 60%, this finding was not observed. Further studies are necessary to evaluate the effect of this finding on asthmatic patients.

Immunoarchitectural characterization of a human skin model reconstructed in vitro

CONTEXT AND OBJECTIVE

Over the last few years, different models for human skin equivalent reconstructed in vitro (HSERIV) have been reported for clinical usage and applications in research for the pharmaceutical industry. Before release for routine use as human skin replacements, HSERIV models need to be tested regarding their similarity with in vivo skin, using morphological (architectural) and immunohistochemical (functional) analyses. A model for HSERIV has been developed in our hospital, and our aim here was to further characterize its immunoarchitectural features by comparing them with human skin, before it can be tested for clinical use, e.g. for severe burns or wounds, whenever ancillary methods are not indicated.

DESIGN AND SETTING

Experimental laboratory study, in the Skin Cell Culture Laboratory, School of Medical Sciences, Universidade Estadual de Campinas.

METHODS

Histological sections were stained with hematoxylin-eosin, Masson's trichrome for collagen fibers, periodic acid-Schiff reagent for basement membrane and glycogen, Weigert-Van Gieson for elastic fibers and Fontana-Masson for melanocytes. Immunohistochemistry was used to localize cytokeratins (broad spectrum of molecular weight, AE1/AE3), high molecular weight cytokeratins (34betaE12), low molecular weight cytokeratins (35betaH11), cytokeratins 7 and 20, vimentin, S-100 protein (for melanocytic and dendritic cells), CD68 (KP1, histiocytes) and CD34 (QBend, endothelium).

RESULTS

Histology revealed satisfactory similarity between HSERIV and in vivo skin. Immunohistochemical analysis on HSERIV demonstrated that the marker pattern was similar to what is generally present in human skin in vivo.

CONCLUSION

HSERIV is morphologically and functionally compatible with human skin observed in vivo.

Essential role of nuclear factor-kappaB for NADPH oxidase activity in normal and anhidrotic ectodermal dysplasia leukocytes

This work investigated the functional role of nuclear factor-kappaB (NF-kappaB) in respiratory burst activity and in expression of the human phagocyte nicotinamide adenine dinucleotide phosphate (NADPH) oxidase genes CYBB, CYBA, NCF1, and NCF2. U937 cells with a stably transfected repressor of NF-kappaB (IkappaBalpha-S32A/S36A) demonstrated significantly lower superoxide release and lower CYBB and NCF1 gene expression compared with control U937 cells. We further tested Epstein-Barr virus (EBV)-transformed B cells from patients with anhidrotic ectodermal dysplasia with immunodeficiency (EDA-ID), an inherited disorder of NF-kappaB function. Superoxide release and CYBB gene expression by EDA-ID cells were significantly decreased compared with healthy cells and similar to cells from patients with X-linked chronic granulomatous disease (X91(0) CGD). NCF1 gene expression in EDA-ID S32I cells was decreased compared with healthy control cells and similar to that in autosomal recessive (A47(0)) CGD cells. Gel shift assays demonstrated loss of recombinant human p50 binding to a NF-kappaB site 5' to the CYBB gene in U937 cells treated with NF-kappaB inhibitors, repressor-transfected U937 cells, and EDA-ID patients' cells. Zymosan phagocytosis was not affected by transfection of U937 cells with the NF-kappaB repressor. These studies show that NF-kappaB is necessary for CYBB and NCF1 gene expression and activation of the phagocyte NADPH oxidase in this model system.

Up-regulation of NADPH oxidase components and increased production of interferon-gamma by leukocytes from sickle cell disease patients

We have previously demonstrated that mononuclear leukocytes from patients with sickle cell disease (SCD) release higher amounts of superoxide compared with normal controls. The aim of this study was to further study the NADPH oxidase system in these patients by investigating gene expression of NADPH oxidase components, phosphorylation of p47(phox) component, and the release of cytokines related to NADPH oxidase activation in mononuclear leukocytes from patients with SCD. gp91(phox) gene expression was significantly higher in monocytes from SCD patients compared with normal controls (P=0.036). Monocytes from SCD patients showed higher levels of p47(phox) phosphorylation compared with normal controls. INF-gamma release by lymphocytes from SCD patients was significantly higher compared with normal controls, after 48 h culture with phytohemagglutinin (P=0.02). The release of TNF-alpha by monocytes from SCD patients and normal controls was similar after 24 and 48 h culture with lipopolysaccharide (P>0.05). We conclude that monocytes from SCD patients show higher levels of gp91(phox) gene expression and p47(phox) phosphorylation, along with increased IFN-gamma release by SCD lymphocytes. These findings help to explain our previous observation showing the increased respiratory burst activity of mononuclear leukocytes from SCD patients and may contribute to inflammation and tissue damage in these patients.

Effects of BAY 41-2272, an activator of nitric oxide-independent site of soluble guanylate cyclase, on human NADPH oxidase system from THP-1 cells

We investigated the effects of the 5-cyclopropyl-2-[1-(2-fluoro-benzyl)-1H-pyrazolo[3,4-b] pyridin-3-yl]-pyrimidin-4-ylamine (BAY 41-2272) on the NADPH oxidase activity, gp91(phox) gene expression, cyclic guanosine-3',5'-monophosphate (cGMP) and cyclic adenosine-3',5'-monophosphate (cAMP) levels in the human myelomonocytic THP-1 cell line. THP-1 cells treated with BAY 41-2272 (0.3-10 microM) for 48 h significantly increased the superoxide anion (O(2)(*-)) release. This increase was not affected when cells were pre-treated with the specific cGMP-phosphodiesterase inhibitor zaprinast, the soluble guanylate cyclase inhibitor 1H-[1,2,4] oxidiazolo[4,3-alpha] quinoxalin-1-one (ODQ), the adenylate cyclase inhibitor 9-(tetrahydro-2-furanyl) adenine (SQ 22,536) or the nitric oxide synthase inhibitor N(omega)-nitro-l-arginine methyl ester (l-NAME). In addition, BAY 41-2272 (3 and 10 microM; 48 h) was able to increase gp91(phox) gene expression on THP-1 cells. The pre-treatment with zaprinast, 3-isobutyl-l-methyl-xanthine (IBMX; 0.5 mM), ODQ, SQ 22,536 or l-NAME caused no additional effect on the expression of gp91(phox) evoked by BAY 41-2272. Treatment of THP-1 cells with BAY 41-2272 caused a significant increase in cGMP and cAMP levels. Our findings show that BAY 41-2272 caused a significant increase on the O(2)(*-) release and gp91(phox) gene expression by THP-1 cells, and an elevation of intracellular cGMP and cAMP levels. However, we could not detect a clear correlation between both O(2)(*-) release and gp91(phox) gene expression with activation of cGMP and cAMP signaling pathways.

Hypopituitarism following severe traumatic brain injury

Although hypopituitarism is a known complication of traumatic head injury, it may be under-recognized due to its subtle clinical manifestations. To address this issue, we determine the prevalence of neuroendocrine abnormalities in patients rehabilitating from severe traumatic brain injury (Glasgow Coma Scale < or = 8). 76 patients (mean age 39 +/- 14 yr; range 18-65; 53 males and 23 females; BMI 25.8 +/- 4.2 kg/m2; mean +/- SD) with a severe traumatic brain injury, an average of 22 +/- 10 months before this study (median, 20 months), underwent a series of standard endocrine tests, including TSH, free T4, T4, T3, prolactin, testosterone (males), estradiol (females), cortisol, ACTH, GH, and IGF-I. All subjects also underwent GH response to GHRH + arginine. Growth hormone deficiency (GHD) was defined as a GH response < 9 microg/L to GHRH + arginine and was confirmed by ITT (< 3 microg/L). Pituitary deficiency was shown in 24% of the patients (18/76). 8% (n = 6) had GHD (GH-peak range [GHRH + arginine]: 2.8-6.3 microg/L; GH-peak range [ITT]: 1.5-2.2 microg/L; IGF-I range: 62-174 microg/L). 17% (n = 13) had hypogonadism (total testosterone < 9.5 nmol/L and low gonadotropins in 12 males; low estradiol, and low gonadotropins in 1 female). Total testosterone levels did not correlate with BMI or age. 2 males with hypogonadism also showed a mild hyperprolactinemia (33 and 41 ng/ml). 3% (n = 2) patients had partial ACTH-deficiency (cortisol-peak [ITT] 392 and 417 nmol/L) and 3% (n = 2) had TSH-deficiency. In summary, we have found hypopituitarism in one-fourth of patients with predominantly secondary hypogonadism and GHD. These findings strongly suggest that patients who suffer head trauma must routinely include neuroendocrine evaluations.

Model for human skin reconstructed in vitro composed of associated dermis and epidermis

CONTEXT AND OBJECTIVE

The technique of obtaining human skin with dermis and epidermis reconstructed from cells isolated from patients can enable autologous skin grafting on patients with few donor sites. It also enables in vitro trials on chemicals and drugs. The objective of this work was to demonstrate a method for obtaining human skin composed of associated dermis and epidermis, reconstructed in vitro.

DESIGN AND SETTING

Experimental laboratory study, in the Skin Cell Culture Laboratory of Faculdade de Ciências Médicas, Universidade Estadual de Campinas.

METHODS

Cells from human fibroblast cultures are injected into bovine collagen type I matrix and kept immersed in specific culturing medium for fibroblasts. This enables human dermis reconstruction in vitro. On this, by culturing human keratinocytes and melanocytes, differentiated epidermis is formed, leading to the creation of human skin composed of associated dermis and epidermis, reconstructed in vitro.

RESULTS

We showed that human skin composed of associated dermis and epidermis can be successfully reconstructed in vitro. It is histologically formed in the same way as human skin in vivo. Collagen tissue can be identified in the dermis, with cells and extracellular matrix organized in parallel to multilayer epidermis.

CONCLUSIONS

It is possible to obtain completely differentiated human skin composed of associated dermis and epidermis, reconstructed in vitro, from injection of human fibroblasts into bovine collagen type I matrix and culturing of human keratinocytes and melanocytes on this matrix.

The Effect of IFN-γ and TNF-α on the NADPH Oxidase System of Human Colostrum Macrophages, Blood Monocytes, and THP-1 Cells

The aim of this work was to analyze the effect of Interferon-gamma (IFN-gamma) and tumor necrosis factor-alpha (TNF-alpha) on NADPH oxidase activity and gp91-phox gene expression in human colostrum macrophages (CM), peripheral blood monocytes (PBM), and myelomonocytic THP-1 cells. We also investigated the effect of IFN-gamma on the release of TNF-alpha by these cells. Our results show that under basal culture conditions, CM release more superoxide than PBM and THP-1 cells (p < 0.05). The addition of IFN-gamma, alone or in combination with TNF-alpha, increased spontaneous superoxide release by PBM and THP-1 cells (p < 0.05) and increased phorbol myristate acetate (PMA)-stimulated superoxide release by CM, PBM, and THP-1 cells (p < 0.05). The NADPH oxidase activity of THP-1 cells consistently remained lower than that of CM or PBM, despite a dramatic response to IFN-gamma and TNF-alpha. Under basal conditions, gp91-phox gene expression was significantly higher in CM and PBM compared with THP-1 cells (p < 0.05). The addition of IFN-gamma alone or in combination with TNF-alpha caused a dramatic increase in gp91-phox gene expression in THP-1 cells (p < 0.05) but not in CM or PBM. Under basal conditions or in the presence of IFN-gamma, CM released more TNF-alpha than PBM or THP-1 cells (p < 0.05). In addition, PBM released more TNF-gamma than THP-1 cells (p < 0.05). IFN-gamma did not significantly augment the release of TNF-alpha by these cells (p > 0.05). Thus, IFN-gamma and TNF-alpha induced equivalent gp91-phox gene expression in THP-1 cells compared with CM or PBM but did not bring about equivalent NADPH oxidase activity. TNF-alpha release was higher in more mature cells. This partial divergence of gp91- phox gene expression, NADPH oxidase activity, and TNF-alpha release is probably a consequence of different events of myeloid cell biology and relates at least in part to cell differentiation state.

Superoxide release and cellular gluthatione peroxidase activity in leukocytes from children with persistent asthma

Asthma is an inflammatory condition characterized by the involvement of several mediators, including reactive oxygen species. The aim of the present study was to investigate the superoxide release and cellular glutathione peroxidase (cGPx) activity in peripheral blood granulocytes and monocytes from children and adolescents with atopic asthma. Forty-four patients were selected and classified as having intermittent or persistent asthma (mild, moderate or severe). The spontaneous or phorbol myristate acetate (PMA, 30 nM)-induced superoxide release by granulocytes and monocytes was determined at 0, 5, 15, and 25 min. cGPx activity was assayed spectrophotometrically. The spontaneous superoxide release by granulocytes from patients with mild (N = 15), moderate (N = 12) or severe (N = 6) asthma was higher at 25 min compared to healthy individuals (N = 28, P < 0.05, Duncan test). The PMA-induced superoxide release by granulocytes from patients with moderate (N = 12) or severe (N = 6) asthma was higher at 15 and 25 min compared to healthy individuals (N = 28, P < 0.05 in both times of incubation, Duncan test). The spontaneous or PMA-induced superoxide release by monocytes from asthmatic patients was similar to healthy individuals (P > 0.05 in all times of incubation, Duncan test). cGPx activity of granulocytes and monocytes from patients with persistent asthma (N = 20) was also similar to healthy individuals (N = 10, P > 0.05, Kruskal-Wallis test). We conclude that, under specific circumstances, granulocytes from children with persistent asthma present a higher respiratory burst activity compared to healthy individuals. These findings indicate a risk of oxidative stress, phagocyte auto-oxidation, and the subsequent release of intracellular toxic oxidants and enzymes, leading to additional inflammation and lung damage in asthmatic children.

Model of human epidermis reconstructed in vitro with keratinocytes and melanocytes on dead de-epidermized human dermis

CONTEXT

Recent progress in the field of epithelial culture techniques has allowed the development of culture systems in which the reconstructed epidermis presents characteristics of morphological differentiation similar to those seen in vivo. Human epidermis reconstructed in vitro may be used as the best alternative for the in vitro testing of the toxicology and efficiency of products for topical use, as well as in the treatment of skin burns and chronic skin ulcers.

OBJECTIVE

To demonstrate a method for obtaining human epidermis reconstructed in vitro, using keratinocytes and melanocytes cultivated on dead de-epidermized human dermis.

TYPE OF STUDY

Experimental/laboratory.

SETTING

Skin Cell Culture Laboratory of the Faculdade de Ciências Médicas, Universidade Estadual de Campinas, Campinas, São Paulo, Brazil.

PROCEDURE

Human keratinocytes and melanocytes cultured in vitro were grown on a biological matrix (dead de-epidermized human dermis) and the system was kept at an air-liquid interface, in a suitable culturing medium, until a stratified human epidermis was formed, maintaining the histological characteristics of the epidermis in vivo.

RESULTS

It was histologically demonstrated that it is possible to reproduce a differentiated epidermis through keratinocytes and melanocytes cultured on dead de-epidermized human dermis, thus obtaining a correctly positioned human epidermis reconstructed in vitro with functional keratinocytes and melanocytes that is similar to in vivo epidermis.

CONCLUSIONS

It is possible to obtain a completely differentiated human epidermis reconstructed in vitro from keratinocyte and melanocyte cultures on a dead de-epidermized human dermis.

Melanocyte transplantation for the treatment of vitiligo: effects of different surgical techniques

This paper presents the results of a pilot clinical trial study, conducted on 11 patients with stable vitiligo at the vitiligo outpatient clinic of The Unicamp University Hospital, between March 2000 and December 2001. This study was in accordance with the ethical standards of the Institutional Review Board. The patients were concomitantly treated with four different types of surgical techniques in 44 areas randomly chosen. There was a 90-day follow-up period. The following treatments were carried out: only cryotherapeutic treatment (OC); cryotherapy plus melanocyte culture medium (CM); cryotherapy plus transplantation of non-cultured melanocytes and keratinocytes (KM); and cryotherapy plus transplantation of cultured melanocytes (CC). The appearance of repigmentation and its evolution were followed all along the treatments. In the case of OC and CM no repigmentation occurred. Progressive repigmentation was observed over a period of 90 days in the case of KM and CC. In these two groups there was a significant reduction in the achromic areas during this time but no significant difference was found between the two treatments.

[Glucose-6-phosphate dehydrogenase deficiency with recurrent infections: case report]

OBJECTIVE: To report a case of rare neutrophil functional disorder with clinical and laboratory findings similar to those of chronic granulomatous disease. METHODS: Patient with extremely reduced level of glucose-6-phosphate dehydrogenase and recurrent infections that improved after continuous use of cotrimoxazole. The patient presented leukocytes with defective respiratory burst, similar to what occurs in chronic granulomatous disease. COMMENTS: The diagnosis of glucose-6-phosphate dehydrogenase deficiency in neutrophils should be considered in any patient with hemolytic anemia whose level of G6PD is extremely low or in any patient that presents recurrent infections as differential diagnosis of chronic granulomatous disease.

Incidence and natural history of phrenic neuropathy occurring during open heart surgery

OBJECTIVE

To study the incidence of phrenic neuropathy following coronary artery bypass grafting and determine long-term outcome.

DESIGN

Prospective observational.

SETTING

Surgical ICU in a university hospital, out-patient follow-up.

PATIENTS

Ninety-two consecutive patients undergoing open heart surgery.

INTERVENTIONS

None.

MEASUREMENTS

Chest radiographs (CXR) 48 to 72 h post-operatively, ultrasonography of diaphragm, phrenic nerve conduction studies, diaphragmatic electromyogram, each repeated every 1 to 3 months until normal.

MAIN RESULTS

Seventy-eight of 92 (78 percent) patients had abnormal radiographs, 42 of 78 (54 percent) with abnormal CXRs had abnormal diaphragm motion, 24 of 42 (57 percent) with abnormal motion had phrenic neuropathy. Patients with normal diaphragm motion improved faster than those without; patients with normal nerve conduction (and abnormal motion) improved faster than those with abnormal nerve conduction.

CONCLUSIONS

Phrenic neuropathy is relatively common if sensitive tests are utilized for diagnosis. Nerve conduction studies can predict duration of morbidity. Most patients have low morbidity and recover fully. Abnormal diaphragm motion alone is not diagnostic of phrenic nerve injury.

Scintigraphic studies of rectal emptying in patients with constipation and defecatory difficulty

We prospectively evaluated 38 adult patients with chronic constipation with and without defecatory difficulties using a newly described scintigraphic test to measure rectal emptying and compared them to 20 healthy controls. All patients underwent anorectal manometry, and 30 who complained of infrequent defecation underwent a colonic transit study using radiopaque markers. Control subjects promptly evacuated both 100 ml and 200 ml artificial stool in a characteristic fashion, but three evacuated none of the 100-ml volume and two had no evacuation of the 200-ml stool (inhibited controls). Constipated patients exhibited three patterns of emptying: (1) normal emptying of both volumes (47%); (2) poor emptying of both volumes or inhibited defecation (29%); and (3) normal emptying of the 200-ml but abnormal evacuation of the 100-ml volume (24%). An abnormal expulsion pattern during manometry occurred in 21% of patients and was strongly associated with the inhibited defecation pattern. However, defecation patterns could not be predicted on the basis of age, gender, symptoms, duration of complaints, colonic transit, or other rectal manometric parameters. Although rectal scintigraphy has potential advantages as a diagnostic test in terms of quantitation and decreased radiation exposure, the inability of the test to distinguish patients with slow transit constipation and defecatory complaints makes the potential utility of this test of uncertain value in clinical and investigative settings.

Pharmacokinetics of dexamethasone and its phosphate ester

Dexamethasone in form of its phosphate was given intravenously in two different doses (1.5 mg kg-1 and 15 mg). Plasma levels of the ester and dexamethasone were measured and pharmacokinetic parameters were calculated. The results indicate no dose-dependency of the pharmacokinetic parameters in the investigated range for dexamethasone. Conversion from the prodrug to the active form was rapid; maximum dexamethasone plasma concentrations were reached after 10 min. The results were verified by dexamethasone level monitoring in patients after chronic dosing. Predicted and achieved steady state levels agreed well.

[Pharmacokinetics and pharmacodynamics of prednisolone following extremely high dosage as prednisolone hemisuccinate]

Plasma levels of prednisolone and prednisolone hemisuccinate of volunteers were measured with HPLC following i.v. injections of 1200 and 75 mg of prednisolone, given as the water-soluble hemisuccinate ester. The hemisuccinate ester is hydrolyzed relatively quickly with a plasma half-life between 18 and 25 min, and the resulting prednisolone has a plasma half-life of 3.5-3.7 h. The dose dependency of the pharmacokinetic parameters indicates a partial saturation of the metabolizing enzymes as consequence of the application of the high dose of prednisolone. In saliva no hemisuccinate could be detected. The prednisolone saliva concentration corresponds with those of non-protein-bound prednisolone in plasma measured at the same time. Only minor quantities of intact ester (1-8%) or intact prednisolone (2-4%) are excreted in urine. Following the application of 1200 mg prednisolone the endogenous cortisol level is partially suppressed only 24 h after the i.v. injection; 48 h later the difference from the basis value is not statistically significant. Leukocytosis and granulocytosis are at maximum 24 h after the injection of the high dose, and after 48 h normal values are observed. Lymphocytes and monocytes fall below normal levels for a longer time after 1200 mg compared to 75 mg, the minimum is between 4 and 8 h. Glucose levels are enhanced dose-dependently. They are normalized even after the extremely high dose at 24 h. Sodium, potassium, calcium, plasma proteins, urea, creatinine, hematocrit and hemoglobin showed no significant differences within 48 h following the injections.

Pharmacokinetics of prednisolone after high doses of prednisolone hemisuccinate

Prednisolone in the form of its hemisuccinate was given intravenously in two different doses (1200 mg and 75 mg). Plasma levels of the ester and prednisolone were measured and pharmacokinetic parameters were calculated. The results indicate a dose-dependency in the pharmacokinetics of both hemisuccinate and the free alcohol. For the high dose 8 per cent of the administered ester was found unchanged in the urine indicating incomplete conversion of the pro-drug. Comparison with previous studies leads to the conclusion that prednisolone shows doubled non-linear pharmacokinetics with higher total body clearance in the medium dose range than in the low and high dose range. Volume of distribution changes accordingly, but overall elimination rate remains remarkably constant. Saliva levels of prednisolone were low and agree reasonably well with calculated plasma concentrations of free, non-protein-bound prednisolone. No prednisolone hemisuccinate was found in saliva.

Kinetics of methylprednisolone and its hemisuccinate ester

Methylprednisolone in the form of its hemisuccinate ester was injected intravenously in doses of 10 mg/kg and 63.1 mg. Plasma levels of methylprednisolone and of the ester were measured and their kinetics were calculated. Results indicate dose dependency in the kinetics of both. About 10% of the dose was excreted unchanged as hemisuccinate in the urine, indicating incomplete conversion of the prodrug. When methylprednisolone (80 mg) was also taken by mouth, the relative bioavailability of the tablets was 99%. Saliva levels of methylprednisolone were low but paralleled plasma levels in the postdistribution phase. No methylprednisolone hemisuccinate was found in saliva.

Simultaneous determination of glucocorticoid alcohols, their succinates and hydrocortisone in plasma

A reversed-phase high-performance liquid chromatographic (HPLC) assay is described for the simultaneous determination of methylprednisolone, methylprednisolone-21-hemisuccinate and endogenous hydrocortisone in biological fluids. This assay is also applicable to the determination of prednisolone-21-hemisuccinate in the presence of prednisolone and hydrocortisone in biological fluids. Prednisolone and hydrocortisone are determined by normal-phase HPLC. The stability of hemisuccinate esters in ampoules, in saline and in plasma has been studied. Whereas the esters were stable in saline at 37 degrees C, they were considerably hydrolysed in plasma at the same temperature. Comparison of hydrocortisone levels obtained by HPLC and radioimmunoassay (RIA) showed the large influence of the cross-reactivity of methylprednisolone and hydrocortisone in the presence of high serum concentrations of methylprednisolone.