In Vitro and In Vivo Sustained Zero-Order Delivery of Rapamycin (Sirolimus) From a Biodegradable Intraocular Device.

PURPOSE: We created implantable intraocular devices capable of constant and continuous rapamycin release on the scale of months to years. METHODS: Polycaprolactone (PCL) thin films were used to encapsulate rapamycin to create implantable and biodegradable intraocular devices. Different film devices were studied by modifying the size, thickness, and porosity of the PCL films. RESULTS: In vitro release of rapamycin was observed to be constant (zero-order) through 14 weeks of study. Release rates were tunable by altering PCL film porosity and thickness. In vivo release of rapamycin was observed out through 16 weeks with concentrations in the retina-choroid in the therapeutic range. Rapamycin concentration in the blood was below the lower limit of quantification. The drug remaining in the device was chemically stable in vitro and in vivo, and was sufficient to last for upwards of 2 years of total release. The mechanism of release is related to the dissolution kinetics of crystalline rapamycin. CONCLUSIONS: Microporous PCL thin film devices demonstrate good ocular compatibility and the ability to release rapamycin locally to the eye over the course of many weeks.

Characterization of monocarboxylate uptake and immunohistochemical demonstration of monocarboxylate transporters in cultured rabbit corneal epithelial cells.

OBJECTIVES: This study aimed to characterize the mechanisms of monocarboxylate uptake by cultured rabbit corneal epithelial cells (RCECs) using l- and d-lactic acids as model substrates. METHODS: l-/d-Lactic acid uptake was evaluated by measuring the accumulation in confluent RCECs. Also, we demonstrated the distribution of monocarboxylate transporters (MCTs) in RCECs by immunohistochemistry. KEY FINDINGS: The accumulation of (14) C-labelled l- and d-lactic acids was dependent on time, pH and temperature. The Arrhenius plots of the uptake were biphasic. The initial uptake of (14) C-labelled l-lactic acid exhibited concentration dependence and was greater than that of the d-isomer. The initial uptake of (14) C-labelled l- and d-lactic acids involved saturable and nonsaturable processes; the saturable process exhibited higher affinity for l-lactic acid than for the d-isomer. l-/d-lactic acid uptake was inhibited by chiral monocarboxylate in a stereoselective manner. The uptake of (14) C-labelled l- and d-lactic acids was sensitive to metabolic inhibitors and other monocarboxylates. MCT expression in RCECs was confirmed immunohistochemically. In particular, MCT2 expression was detected in RCECs, whereas MCT1, MCT4 and MCT5 expression was detected in the surface layer. CONCLUSION: These results indicate that the carrier-mediated transport system specific for monocarboxylates elicits lactic acid uptake in RCECs. Therefore, the transcorneal permeation of drugs with a monocarboxylic moiety may be dependent on the activity of a specific pH-dependent transporter as well as passive diffusion according to the pH-partition theory.

Risk factors for wheezing, eczema and rhinoconjunctivitis in the previous 12 months among six-year-old children in Himeji City, Japan: food allergy, older siblings, day-care attendance and parental allergy history.

BACKGROUND: The aim of this study was to clarify whether some environmental and genetic factors (food allergy, older siblings, early day-care attendance and parents' allergy history) are related to the development of allergic symptoms (wheezing in the previous 12 months [WP], eczema symptoms in the previous 12 months [EP], and rhinoconjunctivitis symptoms in the previous 12 months [RP]) in Japanese children. METHODS: Using the modified version of the International Study on Asthma and Allergies in Childhood (ISSAC) questionnaire, we studied the prevalence of WP, EP and RP among six-year-old children attending 72 primary schools throughout Himeji City, Japan, during the two years from 2005 to 2006. RESULTS: Food allergy and parents' history of allergy showed a significant relationship with the prevalence of WP, EP and RP. Day-care attendance in the first two years of life and presence of older siblings showed a significant inverse relationship with the prevalence of RP. However, neither day-care attendance nor presence of older siblings was related to the development of W and ER. CONCLUSIONS: Among Japanese children, food allergy and parents' history of allergy are risk factors for WP, ES or RS. However, early day-care attendance and presence of older siblings might be protective factors against RS. Infections in early life may affect the prevalence of rhinoconjunctivitis in six-year-old children.

Characterization of histopathology and gene-expression profiles of synovitis in early rheumatoid arthritis using targeted biopsy specimens.

The disease category of early rheumatoid arthritis (RA) has been limited with respect to clinical criteria. Pathological manifestations of synovitis in patients whose disease is clinically classified as early RA seem to be heterogeneous, with regular variations. To clarify the relation between the molecular and histopathological features of the synovitis, we analyzed gene-expression profiles in the synovial lining tissues to correlate them with histopathological features. Synovial tissues were obtained from knee joints of 12 patients with early RA by targeted biopsy under arthroscopy. Surgical specimens of long-standing RA (from four patients) were examined as positive controls. Each histopathological parameter characteristic of rheumatoid synovitis in synovial tissues was scored under light microscopy. Total RNAs from synovial lining tissues were obtained from the specimens selected by laser capture microdissection and the mRNAs were amplified by bacteriophage T7 RNA polymerase. Their cDNAs were analyzed in a cDNA microarray with 23,040 cDNAs, and the levels of gene expression in multilayered lining tissues, compared with those of normal-like lining tissues in specimens from the same person, were determined to estimate gene-expression profiles characteristic of the synovial proliferative lesions in each case. Based on cluster analysis of all cases, gene-expression profiles in the lesions in early RA fell into two groups. The groups had different expression levels of genes critical for proliferative inflammation, including those encoding cytokines, adhesion molecules, and extracellular matrices. One group resembled synovitis in long-standing RA and had high scores for some histopathological features - involving accumulations of lymphocytes and plasma cells - but not for other features. Possible differences in the histopathogenesis and prognosis of synovitis between the two groups are discussed in relation to the candidate genes and histopathology.