Mechanistic evaluation of the effect of sodium-dependent glucose transporter 2 inhibitors on delayed glucose absorption in patients with type 2 diabetes mellitus using a quantitative systems pharmacology model of human systemic glucose dynamics

Sodium-dependent glucose transporter (SGLT) 2 is specifically expressed in the kidney, while SGLT1 is present in the kidneys and small intestine. SGLT2 inhibitors are a class of oral antidiabetic drugs that lower elevated plasma glucose levels by promoting the urinary excretion of excess glucose through the inhibition of renal glucose reuptake. The inhibition selectivity for SGLT2 over SGLT1 (SGLT2/1 selectivity) of marketed SGLT2 inhibitors is diverse, while SGLT2/1 selectivity of canagliflozin is relatively low. Although canagliflozin suppresses postprandial glucose levels, the degree of contribution for SGLT1 inhibition to this effect remains unproven. To analyze the effect of SGLT2 inhibitors on postprandial glucose level, we constructed a novel quantitative systems pharmacology (QSP) model, called human systemic glucose dynamics (HSGD) model, integrating intestinal absorption, metabolism, and renal reabsorption of glucose. This HSGD model reproduced the postprandial plasma glucose concentration–time profiles during a meal tolerance test under different clinical trial conditions. Simulations after canagliflozin administration showed a dose-dependent delay of time (T_max,glc) to reach maximum concentration of glucose (C_max,glc), and the delay of T_max,glc disappeared when inhibition of SGLT1 was negated. In addition, contribution ratio of intestinal SGLT1 inhibition to the decrease in C_max,glc was estimated to be 23%–28%, when 100 and 300 mg of canagliflozin are administered. This HSGD model enabled us to provide the partial contribution of intestinal SGLT1 inhibition to the improvement of postprandial hyperglycemia as well as to quantitatively describe the plasma glucose dynamics following SGLT2 inhibitors.     

Functional neuro-vascularized muscle transfer for oncological reconstruction of extremity sarcoma

The strategy of limb salvage following surgical resection of skeletal tumor has led to an increased demand for more complex reconstructive options in order to achieve better functional outcomes. Functional neuro-vascularized muscle transfer (FMT) is a beneficial tool for restoring joint movement involving the reconstruction of “movement” in the affected extremity. Until now, however, the clinical application of FMT was mainly limited to trauma cases and to date, very few studies have focused on musculoskeletal oncology. In this study, we reviewed patients who underwent wide resection for extremity sarcoma and functional reconstruction using FMT and discussed the advantages, indications and complications of the procedure.     

Correlation of within-individual fluctuation of depressed mood with prefrontal cortex activity during verbal working memory task: optical topography study

Previous studies showed that interindividual variations in mood state are associated with prefrontal cortex (PFC) activity. In this study, we focused on the depressed-mood state under natural circumstances and examined the relationship between within-individual changes over time in this mood state and PFC activity. We used optical topography (OT), a functional imaging technique based on near-infrared spectroscopy, to measure PFC activity for each participant in three experimental sessions repeated at 2-week intervals. In each session, the participants completed a self-report questionnaire of mood state and underwent OT measurement while performing verbal and spatial working memory (WM) tasks. The results showed that changes in the depressed-mood score between successive sessions were negatively correlated with those in the left PFC activation for the verbal WM task (ρ = -0.56, p < 0.05). In contrast, the PFC activation for the spatial WM task did not co-vary with participants' mood changes. We thus demonstrated that PFC activity during a verbal WM task varies depending on the participant's depressed mood state, independent of trait factors. This suggests that using optical topography to measure PFC activity during a verbal WM task can be used as a potential state marker for an individual's depressed mood state.     

Nuclear, but not cytoplasmic, localization of survivin as a negative prognostic factor for survival in upper urinary tract urothelial carcinoma

Survivin, a member of the inhibitor of apoptosis protein gene family, inhibits apoptosis and promotes mitosis. We determined whether nuclear or cytoplasmic localization of survivin could predict survival of patients with upper urinary tract urothelial carcinoma (UUTUC). Immunohistochemical staining for survivin was carried out on archival specimens from 125 consecutive patients with UUTUC who underwent radical nephroureterectomy. Nuclear and cytoplasmic staining of survivin was scored and compared with clinicopathologic features and cancer-specific survival (CSS). Nuclear expression of survivin was significantly correlated with tumor grade (p?<?0.001), lymphovascular invasion (p?=?0.022) and poor survival with an estimated 5-year CSS probability of 54 % for tumors with nuclear expression of survivin vs. 73 % for those without nuclear expression of survivin (hazard ratio?=?2.19; 95 % confidence interval?=?1.02–4.70; p?=?0.043). The 5-year cancer-specific survival rates of patients with cytoplasmic survivin-negative and -positive tumors were 66 and 67 %, respectively. There was no difference in survival between patients with cytoplasmic survivin-negative tumors and those with cytoplasmic survivin-positive tumors. Using univariate analysis, nuclear survivin expression, tumor grade, pathological T stage, pathological N stage, and lymphovascular invasion were the predictive variables for CSS. In contrast, cytoplasmic survivin expression had no prognostic relevance. These data suggest that nuclear accumulation of survivin represents biologic aggressiveness and that nuclear survivin is a negative prognostic marker in patients with resected UUTUC.     

Enhanced enteric invasion of scrapie agents into the villous columnar epithelium via maternal immunoglobulin

Transmissible spongiform encephalopathies (TSE) are caused by dietary oral exposure to infectious prion proteins (PrPSc); however, the mechanism behind the uptake of PrPSc in the intestines is poorly understood. In addition, epidemiological studies of BSE showed that most cattle are exposed to the agents in the first 6 months of life, during the suckling and weaning periods. In the present study, to elucidate the enteric invasion mechanism of prions and to investigate the age-dependent transmission mechanism suggested by epidemiological studies, wild-type and SCID mice were orally administered brain homogenate from scrapie (Tsukuba 1)-infected mice during the suckling and weaning stages, before being analyzed histopathologically. PrPSc was found to be incorporated into the villous columnar epithelial cells and was also detected in the villous lacteal of 15-day-old suckling mice. However, no such uptake of PrPSc was observed in the weaned mice at 25-days-old. Four different strains of mice were tested. There was no mouse strain difference in the frequency of PrPSc positive columnar epithelial cells. In addition, the uptake of PrPSc in suckling SCID mice lacking maternal antibodies was significantly lower than that in the wild-type suckling mice, and the uptake of PrPSc was enhanced by dilution with purified IgG. In the present study, it was suggested that the weaning period and maternal immunoglobulin are important risk factors for the oral transmission of PrPSc.     

Amyloid deposition in primary pulmonary marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue

A rare association between primary pulmonary marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma), and pulmonary immunoglobulin light chain (AL) amyloidosis is described in a 65-year-old woman suffering from rheumatoid arthritis (RA). All four nodules in the resected upper lobe of the lung had a similar histological appearance. They were composed of small-medium-sized atypical lymphocytes. Centrocyte-like cells had lymphoepithelial lesions. Immunohistochemically, the tumor cells clonally expressed B-cell markers, and demonstrated clonal rearrangement of the immunoglobulin heavy chain gene on polymerase chain reaction. Based on these findings the diagnosis of primary pulmonary MALT lymphoma was made. In addition, uniform eosinophilic material deposition was identified randomly within the tumor. It was Congophilic and exhibited apple-green birefringence on polarizing microscopy, and remained unaffected by potassium permanganate digestion. Deposited material was immunoreactive to lambda light chain. It was concluded that this material was AL amyloid in primary pulmonary MALT lymphoma. Plasma cells with mRNA of lambda chain was found infiltrated along the border of amyloid deposition. Finally, it is speculated that primary pulmonary MALT lymphoma developing in an autoimmune setting, RA in the present case, is associated with overproduction and abnormal clearance of immunoglobulin by the tumor cells, resulting in AL amyloidosis within the tumor.     

Methtrexate-associated lymphoproliferative disorders. A clinicopathological study of 13 Japanese cases

We conducted clinicopathological and immunohistochemical analyses to investigate the prevalence of Epstein-Barr virus (EBV) among 13 cases with methotrexate (MTX)-associated lymphoproliferative disorder (LPD). The subjects of this study were four men and nine women ranging in age from 53 to 78 years (mean: 63 years). All 13 patients had received low dose MTX therapy for 1-13 years before the onset of LPD (mean: 5.8 years). LPDs were found at extranodal sites in six cases, and the disease stage was advanced in seven cases. The present study confirmed certain aspects of a previous observation made in the USA, including the following findings (i) the cases commonly showed diffuse large B-cell lymphomas (n=4) and Hodgkin lymphomas (HL) (n=3), (ii) EBV-encoded small RNA (EBER) + cells were identified in seven cases (60%), which is a much higher percentage than would be expected in lymphomas occurring in a general population, and (iii) three cases of polymorphous small lymphocytic or lymphoplasmacytic infiltrate achieved spontaneous remission of LPDs after MTX withdrawal. Of seven cases of EBER + in our series, three cases were PSLLPI, and two were HL. EBER + tumor cells were detected in only two (30%) of the seven cases with non-Hodgkin lymphomas. The present study suggests that EBV- associated non-Hodgkin lymphomas comprise only a portion of all non-Hodgkin lymphomas among MTX-associated LPDs.     

Distribution of liposomes into brain and rat brain tumor models by convection-enhanced delivery monitored with magnetic resonance imaging

Although liposomes have been used as a vehicle for delivery of therapeutic agents in oncology, their efficacy in targeting brain tumors has been limited due to poor penetration through the blood-brain barrier. Because convection-enhanced delivery (CED) of liposomes may improve the therapeutic index for targeting brain tumors, we conducted a three-stage study: stage 1 established the feasibility of using in vivo magnetic resonance imaging (MRI) to confirm adequate liposomal distribution within targeted regions in normal rat brain. Liposomes colabeled with gadolinium (Gd) and a fluorescent indicator, 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine-5,5'-disulfonic acid [DiI-DS; formally DiIC(18)(3)-DS], were administered by CED into striatal regions. The minimum concentration of Gd needed for monitoring, correlation of infused volume with distribution volume, clearance of infused liposome containing Gd and DiI-DS (Lip/Gd/DiI-DS), and potential local toxicity were evaluated. After determination of adequate conditions for MRI detection in normal brain, stage 2 evaluated the feasibility of in vivo MRI monitoring of liposomal distribution in C6 and 9L-2 rat glioma models. In both models, the distribution of Lip/Gd/DiI-DS covering the tumor mass was well defined and monitored with MRI. Stage 3 was designed to develop a clinically relevant treatment strategy in the 9L-2 model by infusing liposome containing Gd (Lip/Gd), prepared in the same size as Lip/Gd/DiI-DS, with Doxil, a liposomal drug of similar size used to treat several cancers. MRI detection of Lip/Gd coadministered with Doxil provided optimum CED parameters for complete coverage of 9L-2 tumors. By permitting in vivo monitoring of therapeutic distribution in brain tumors, this technique optimizes local drug delivery and may provide a basis for clinical applications in the treatment of malignant glioma.     

Extensive Distribution of Liposomes in Rodent Brains and Brain Tumors Following Convection-Enhanced Delivery

Liposomes labeled with various markers were subjected to local-regional administration with either direct injection or convection-enhanced delivery (CED) into rodent brains and brain tumor models. Direct injection of liposomes containing attached or encapsulated fluorochromes and/or encapsulated gold particles indicated that tissue localization of liposomes could be sensitively and specifically detected in the central nervous system (CNS). When CED was applied, liposomes achieved extensive and efficient distribution within normal mouse brains. Co-infusion of mannitol further increased tissue penetration of liposomes. Liposomes were also loaded with gadodiamide to monitor their CNS distribution in rats by magnetic resonance imaging (MRI). CED-infused liposomes were readily seen on MRI scans as large regions of intense signal at 2 h, and more diffuse regions at 24 h. Finally, labeled liposomes were infused via CED into tumor tissue in glioma xenograft models in rodent hosts. In intracranial U-87 glioma xenografts, CED-infused liposomes had distributed throughout tumor tissue, including extension into surrounding normal tissue. Greater penetration was observed using 40 versus 90 nm liposomes, as well as with mannitol co-infusion. To our knowledge, this is the first report of CED infusion of liposomes into the CNS. We conclude that CED of liposomes in the CNS is a feasible approach, and offers a promising strategy for targeting therapeutic agents to brain tumors.