Leptin brain entry via a tanycytic LepR-EGFR shuttle controls lipid metabolism and pancreas function

Metabolic health depends on the brain's ability to control food intake and nutrient use versus storage, processes that require peripheral signals such as the adipocyte-derived hormone, leptin, to cross brain barriers and mobilize regulatory circuits. We have previously shown that hypothalamic tanycytes shuttle leptin into the brain to reach target neurons. Here, using multiple complementary models, we show that tanycytes express functional leptin receptor (LepR), respond to leptin by triggering Ca²⁺ waves and target protein phosphorylation, and that their transcytotic transport of leptin requires the activation of a LepR-EGFR complex by leptin and EGF sequentially. Selective deletion of LepR in tanycytes blocks leptin entry into the brain, inducing not only increased food intake and lipogenesis but also glucose intolerance through attenuated insulin secretion by pancreatic β-cells, possibly via altered sympathetic nervous tone. Tanycytic LepRb-EGFR-mediated transport of leptin could thus be crucial to the pathophysiology of diabetes in addition to obesity, with therapeutic implications.

Longitudinal analysis of the peripapillary retinal nerve fiber layer thinning in patients with retinitis pigmentosa

PURPOSE

To investigate longitudinal changes in peripapillary retinal nerve fiber layer (RNFL) thickness in patients with retinitis pigmentosa (RP).

METHODS

We re-examined 103 RP patients whose RNFL thickness was previously examined and reported. RNFL thickness was measured using Stratus optical coherence tomography and was compared with the previous measurements. The results were also compared with that of previously reported normal subjects. Association between the decrease rate and visual acuity, and visual field was also investigated.

RESULTS

The mean follow-up period was 56.9 months. After excluding the patients in whom RNFL images were of poor quality, 88 patients were eventually analyzed. The average RNFL thickness decreased from 105.8 to 98.2 μm during the period, with the average rate of decrease being 1.6 μm/year. The decrease in RNFL was more evident in superior and inferior sectors. Cross-sectional linear regression analysis also revealed an age-dependent decrease in RNFL, with the slower rate of decrease being 0.94 μm/year. The decrease in RNFL thickness was significantly faster than that reported in normal subjects. The decrease rate was not associated with visual functions.

CONCLUSION

Age-dependent RNFL thinning occurs at a faster rate in RP patients as compared with that in normal subjects. The result supports the notion that pathologic changes involve inner retina as well as outer retina in eyes with RP. Considering the discrepancy in the rate of RNFL thinning estimated from trend analysis and longitudinal measurement, care should be taken when interpreting the result of cross-sectional analysis.

Characteristics of fine vascular network pattern associated with recurrence of polypoidal choroidal vasculopathy

OBJECTIVE

To characterize an irregular capillary-like structure in the vascular network of eyes with polypoidal choroidal vasculopathy (PCV), and to determine whether its presence after photodynamic therapy (PDT) can be used to predict the clinical course of PCV.

METHODS

We reviewed the clinical records of 29 eyes of 29 patients with PCV, who underwent PDT and confocal retinal angiographic examinations every 3 months. The images obtained before the PDT were compared with those after the PDT. The correlations between angiography findings and recurrences were evaluated.

RESULTS

An area of fine, densely packed capillary-like vessels, named the fine vascular network, was identified within the polypoidal vascular network in 25 of 29 cases at the initial examination. The fine vascular network regressed in 23 cases (92%) after the first PDT. Thereafter, the fine vascular network remained or enlarged in 19 eyes, and 17 (84.5%) of these eyes had a recurrence of the polypoidal lesions or had exudative changes. In contrast, recurrences were found in only 2 of 10 (20%) eyes, whose fine network had regressed without a subsequent enlargement (P<0.001 compared with the former group).

CONCLUSIONS

A fine irregular vascular network is present in the majority of eyes with PCV before PDT. Its presence or expansion after PDT was significantly associated with a recurrence of PCV. Thus, we recommend that this network be monitored after treatment to determine whether a polypoidal vascular network will recur.

Photoreceptor integrity and visual acuity in cystoid macular oedema associated with retinitis pigmentosa

AIMS

To assess the correlation between macular morphology and visual acuity in retinitis pigmentosa (RP) patients with cystoid macular oedema (CME).

DESIGN

Retrospective cross-sectional study.

PATIENTS AND METHODS

Forty-one eyes of 25 RP patients with CME. Patients underwent cross-sectional scans with optical coherence tomography (Stratus OCT). Age, total retinal thickness, photoreceptor thickness, and the transverse and vertical lengths of the cystoid space were measured. Correlation between visual acuity and each of the measurements were examined. Additionally, the status of the inner segment/outer segment junction (IS/OS) was classified as being absent, discontinuous, or distinct. Measurements were then compared among the three groups.

RESULTS

Total retinal thickness or photoreceptor thickness was not correlated with visual acuity. There was a correlation between the transverse length of the cystoid space and visual acuity, although the correlation coefficient was weak (r=0.30). The logMAR visual acuity in the IS/OS absent group (0.67+/-0.43) was worse than that seen in the IS/OS discontinuous (0.22+/-0.19) or IS/OS distinct groups (0.07+/-0.16) (P<0.001).

CONCLUSIONS

When monitoring CME associated with RP, the status of IS/OS is the essential parameter that needs to be examined.

Retinal nerve fiber layer thickness in patients with retinitis pigmentosa

PURPOSE

To study retinal nerve fiber layer (RNFL) thickness in patients with retinitis pigmentosa (RP).

DESIGN

Cross-sectional observational study.

METHODS

One hundred and thirty-seven eyes of 137 patients with RP were examined. The effect of age, gender, laterality, inheritance trait, spherical equivalent refractive error, visual acuity, and the extent of visual field defect on RNFL thickness measured with optical coherence tomography were analyzed by a multiple linear regression model.

RESULTS

The average RNFL thickness was 104.1+/-21.7 microm. The multiple R(2) for the model was 0.349. Among the variables studied, ageing and being male were significant risk factors for thinner RNFL thickness. RNFL thickness was not correlated with inheritance trait, laterality, refractive error, visual acuity, or the extent of visual field defect.

CONCLUSION

RNFL thickness in RP patients was not correlated with visual function but ageing as in the normal subjects. Currently proposed therapies, including photoreceptor rescue/transplantation and visual prosthesis, are based on the premise that the inner retinal structures are relatively retained despite the profound loss of photoreceptors. The present result supports this notion.

Identifying pathogenic genetic background of simplex or multiplex retinitis pigmentosa patients: a large scale mutation screening study

BACKGROUND AND PURPOSE

More than half of the retinitis pigmentosa (RP) cases are genetically simplex or multiplex. To date, 37 causative genes of RP have been identified; however, the elucidation of gene defects in simplex or multiplex RP patients/families remains problematic. The aim of our study was to identify the genetic causes of RP in patients with unknown or non-Mendelian inheritance.

METHODS AND RESULTS

Since 2003, 52 simplex RP patients, 151 patients from 141 multiplex RP families, and six sporadic patients with retinal degeneration were studied. A total of 108 exons of 30 RP-causing genes that harboured the reported mutations were screened by an efficient denaturing high performance liquid chromatography (dHPLC) based assay. Aberrant fragments were subsequently analysed by automatic sequencing. Twenty-six mutations, including two frameshift mutations, one single amino acid deletion, and 23 missense mutations, were identified in 28 probands (14.07%). Eighteen mutations have not been reported to date. Three pairs of combined mutations in different genes were identified in two sporadic cases and one multiplex family, indicating the possibility of novel digenic patterns. Of the 23 missense mutations, 21 were predicted as deleterious mutations by computational methods using PolyPhen, SIFT, PANTHER, and PMut programs.

CONCLUSION

We elucidated the mutation spectrum in Japanese RP patients and demonstrated the validity of the mutation detection system using dHPLC sequencing for genetic diagnosis in RP patients independent of familial incidence, which may provide a model strategy for identifying genetic causes in other diseases linked to a wide range of genes.

An in vitro study of the effect of some dietary components on calculus formation: regulation of calcium phosphate precipitation

OBJECTIVE

We studied the effects of food components on the in vitro formation of calcium phosphate precipitates.

MATERIALS AND METHODS

The effects of food components, such as starch, soybean flour, fish meal, rapeseed oil, and coconut oil, on calcium phosphate precipitation were studied using a pH drop method.

RESULTS

Although the addition of starch had no effect on the rate of precipitation of amorphous calcium phosphate (ACP), it increased both the rate of transformation of ACP to hydroxyapatite (HAP) and the induction time (i.e. time for the initiation of transformation of ACP to HAP to occur); this was irrespective of the heat treatment of the starch. Amylopectin (insoluble constituent of starch) was effective in increasing the rate of HAP transformation, but amylose (soluble constituent of starch) was not. Oil specimen obtained from rapeseed (400 microl ml(-1)) increased the entire reaction of calcium phosphate precipitation, but that from coconut did not. Protein food, such as soybean flour and fish meal, decreased the rate of transformation of ACP to HAP and increased the induction time, while they had no effect on the rate of ACP precipitation.

CONCLUSION

These results suggest that carbohydrate and oil (both are staple diets for the humans) enhance oral calcification (dental calculus formation or re-mineralization of tooth enamel), while side dishes of protein food would decrease it.

Crystal structure and preferred conformation of beta-lactams derived from (S)-1-arylethyl isocyanates and vinyl ethers

The configurational analysis of beta-lactams prepared from [2 + 2] cycloaddition of vinyl ethers to pure enantiomers of 1-arylethyl isocyanates was carried out by high resolution 1H NMR. The addition of a chiral shift reagent revealed that the most important conformation of the studied beta-lactams in solution is that in which the methine proton, of the exocyclic stereogenic carbon, points towards the carbonyl oxygen atom. Since the configuration of the stereogenic exocyclic carbon is known, the orientation of the aromatic ring allows the correlation of the chemical shifts with the absolute configuration of the new stereogenic centers. This method is particularly useful to establish the stereochemistry of oily beta-lactams having the N-(1-arylethyl) group. The X-ray crystallographic analysis carried out with (1R,5S)-7-[(1S)-1-(1-naphthyl) ethyl]-2-oxa-7-azabicyclo[3.2.0]heptan-6-one, is consistent with the proposed model for beta-lactams in solution.

The effect of nitric oxide production by sinusoidal endothelial cells on preservation injury during cold ischemia

Multifactorial elements are responsible for preservation and reperfusion injury in liver allografts. Sinusoidal endothelial cells (SECs) are a primary target of cold preservation injury of the liver. We examined the correlation between nitric oxide (NO) production by SECs and their injury during cold preservation. SECs were isolated from rat livers and preserved in either Euro-Collins (EC) or University of Wisconsin (UW) solution. Injury to the SECs was more severe when preserved in the EC solution than in the UW solution during cold ischemia. In addition, NO production by SECs was found to be proportionate to the cell injury. Cell viability was not improved by the addition of NO inhibitor, L-NMMA. Further, NO inhibitor was detrimental to the SECs in a 24-h preservation in UW solution. LDH release by SECs preserved in UW solution supplemented with L-NMMA was 11.10+/-2.03 IU/l, while that in UW solution alone was 3.70+/-0.70 IU/l (P<0.01). Together, our results suggest that NO protects SECs during cold preservation and that NO from SECs may have beneficial effects on the liver during cold ischemia.

Experimental hypocalcemia induced by hemodialysis in goats

To evaluate whether hemodialysis with a dialysate containing no calcium (Ca-free HD) can induce hypocalcemia and restore the clinical signs and blood biochemical changes in naturally occurred hypocalcemic disorder in ruminants, the clinical signs and the changes in plasma electrolytes and minerals concentrations were observed in goats during 6-hr hemodialysis. The four goats received hemodialysis with the dialysate containing calcium (Ca HD), and 10 days later they had Ca-free HD. The plasma ionized Ca (Ca++) and total Ca (TCa) concentrations were not affected by Ca HD, whereas the levels significantly decreased during whole period of Ca-free HD. The Ca++ and TCa concentrations were 0.69+/-0.06 mmol/l and 5.9+/-0.3 mg/dl at 6 hr of Ca-free HD, respectively. The clinical signs observed during Ca-free HD seemed to resemble to those in naturally occurred hypocalcemic cases that were reported previously. Therefore, Ca-free HD was suggested to be one of the possible methods to induce experimental hypocalcemia in ruminants.

Placenta accreta/increta. Review of 10 cases and a case report

A review of the patients seen at the Department of Obstetrics at Dokkyo University Hospital who had suffered placenta accreta/increta in the past 18 years, was performed. There were 10 such cases out of 9,716 deliveries during this period. This incidence is higher than that which has been reported in other Western countries. Forty percent of the patients in our study had placenta accreta/increta accompanied by placenta previa or low lying; 30% had had a prior cesarean section (C/S); 70% had previously experienced dilatation and curettage (D & C); 80% had previously undergone a C/S and/or D & C: and 40% had a history of miscarriage. Three of the ten patients with placenta accreta/increta required a hysterectomy; 2 patients were successfully treated with hemostatic stitches on the endometrium; and the remaining 5 mild cases were treated with removal of the placenta, either manually or with the use of forceps. There was no case of maternal death. In 2 cases, neonatal asphyxia was noted, but the neonate immediately recovered.

Enhancement of enzyme reaction of magnetically anisotropic polyacrylamide gel rods immobilized with ferromagnetic powder and beta-D-galactosidase in an alternating magnetic field

An immobilized polyacrylamide gel containing beta-D-galactosidase and Sr-Ba-ferrite was magnetized in a static magnetic field. The gel rods (10 mm long, O 2 mm) exhibiting magnetic anisotropy could move at lower than 100 Hz but not at higher than 250 Hz in an alternating magnetic field of 200 Oe. In case of immovability of gel rods, the apparent enzymic activity increased 3 times higher under exposure of an alternating magnetic field of 500 Oe (570 Hz). It could be explained that the ferromagnetic powder inside the gel might vibrate under the influence of elasticity of gel in the alternating magnetic field of 100 or 500 Oe and 0.2-12 kHz. This might facilitate faster diffusion of the substance inside the gel and transportation of the substrate and the product through the surface of gel. Consequently, the enzyme reaction was apparently activated.

Radiographical evaluation of bone maturation in Japanese black beef cattle

Epiphyseal ossification in the radius, ulna, metacarpus, proximal phalanx and tuber calcaneus was examined radiographically in Japanese Black beef cattle. The grade of standard ossification was assessed monthly for each epiphysis. Bone maturations could be divided into 8 grades for the distal radius and distal ulna, 7 grades for the distal metacarpus, 5 grades for the proximal phalanx, and 8 grades for the tuber calcaneus, respectively. The closure of the epiphyseal line completed at the earliest (12-14 months of age) on the proximal phalanx, and at the latest (35-37 months of age) on the distal ulna. Changes in gradings were steep at 0 to 5 months of age but became almost constant after 10 months of age in all the epiphyses. There were no significant differences in bone maturation between the cattle with different sex and breeding conditions.

Racial factors cannot explain superior Japanese outcomes in stomach cancer

OBJECTIVE

To compare the stage-stratified survival of Japanese patients treated in Honolulu according to Western techniques with that of Japanese patients treated in Tokyo according to Japanese techniques, thus eliminating race as a potentially confounding variable.

DESIGN AND PATIENTS

Of 312 Honolulu Japanese patients surviving Western-type gastric resection for neoplasm between 1974 and 1985, 279 were identified with invasive gastric adenocarcinoma unassociated with any second malignancy. This Honolulu cohort, treated by Western methods, was retrospectively compared with a similar, previously described cohort of 3176 Tokyo Japanese patients treated according to Japanese methods.

MAIN OUTCOME MEASURES

American Joint Committee on Cancer/Union Internationale Contre le Cancer criteria for stage-stratified survival.

RESULTS

Despite non-TNM prognostic factors favoring higher survival for the Honolulu Japanese patients, for every TNM stage, we observed higher survival for the Tokyo Japanese patients who were treated according to Japanese techniques. For stage I disease, the survival rates were 86% vs 96%, respectively (P < .001); for state II, 69% vas 77% (P = .15); for stage III, 21% vs 49% (P < .001); and for stage IV, 4% vs 14% (P < .001).

CONCLUSIONS

Because all patients in this study are Japanese, race-related factors or the "different-disease" hypothesis cannot explain these results. Lymphadenectomy-related stage-migration and/or differing therapeutic efficacy seem more likely explanations.

Preventive effects of recombinant human erythropoietin administration on anemia associated with repeated hemodialysis in nephrectomized dogs

The preventive effects of recombinant human erythropoietin (rhEPO) administration on progression of anemia were evaluated during hemodialysis in nephrectomized dogs. In control dogs given no rhEPO, anemia gradually progressed with repeated hemodialysis and with little erythropoietic response observed in the bone marrow. In dogs administered with rhEPO, however, an active erythropoietic response was induced in the bone marrow, indicating that anemia due to hemodialysis was being prevented.

Canine plasma erythropoietin levels in 124 cases of anemia

Erythropoietin (EPO) levels in plasma from 124 clinically anemic dogs were determined by in vivo bioassay. In 81 anemic dogs with normal renal function, the concentration of plasma EPO showed a close correlation with the hemoglobin concentration. The plasma EPO level was obviously decreased in 43 anemic dogs with renal failure. Of these dogs with renal failure, 17 showed no detectable plasma EPO and resulted in the death of these dogs. In the remaining 26 dogs having detectable plasma EPO, the plasma concentration rate of EPO related to blood urea nitrogen and serum creatinine values.

Evaluation of erythropoietin production in dogs with reduced functional renal tissue

This study was designed to determine the quantity of functional renal tissue needed to maintain homeostasis of red blood cell production by evaluating the erythropoietin (EPO) production response to phlebotomic stimulation in the 1/2- and 1/4-kidney dogs surgically prepared. The results showed that the reduction in functional renal tissue caused a decrease in EPO production, which led to the delay in recovery from anemia. In the anemic progress stage, the plasma EPO level showed a transition proportional to the quantity of functional renal tissue immediately after the operation for tissue reduction. The 1/2-kidney dog group still kept such proportional relation even in the recovery stage. Thus, the half of the normal renal tissue was considered sufficiently contributory to EPO production needed to maintain homeostasis of red blood cell production. However, the 1/4-kidney dog group precipitously decreased in plasma EPO level in the recovery stage and fell into an extremely unfavorable anemia. This indicated that homeostatic maintenance in erythropoiesis would be impossible more below a quarter of normal renal tissue. These findings disclosed that reduction in functional renal tissue quantity would sensitively influence homeostatic maintenance of red blood cell production through the decrease in EPO production, even if it does not affect renal function concerned with urine production.

Evaluation of phlebotomy-induced erythropoietin production in the dog

Erythropoietin (EPO) production in dogs was studied by reducing red blood cells with phlebotomy. In this study, the hemoglobin reduction rate (delta %Hb) was newly taken into account as the regulating factor for EPO production, and its usefulness to estimate the stimulating intensity to EPO production was examined. As the result, plasma EPO was highly correlated with delta %Hb showing the importance related to regulation of EPO production, in the increasing plasma EPO by different degrees of phlebotomy, in the change of plasma EPO through the anemia progress and recovery period after severe phlebotomy, and in the initial variation of plasma EPO induced by chronic mild phlebotomy. On the other hand, increasing EPO production appeared at least within 6 hr after acute severe phlebotomy, which revealed significantly higher plasma level compared with the mild chronic phlebotomy, suggesting the effect of time leading to red blood cell reduction on EPO production response. Simultaneously, considering an in vivo EPO half life of 8.4 hr calculated from plasma EPO disappearance after bilateral nephrectomy, endogenous plasma EPO accumulation should be taken into consideration in rapidly increasing of delta %Hb.

Evaluation of plasma erythropoietin levels in normal adult dogs by in vivo bioassay using concentrated plasma

Measurement of plasma erythropoietin level in normal dogs by in vivo bioassay has been considered to be impossible so far. In the present study, we successfully determined it by using concentrated plasma 60 times which allowed the lower limit to 2.7 mU/ml. This normal plasma erythropoietin level was the first to be determined as an in vivo bioactivity and was 9.14 +/- 7.81 mU/ml in 75 normal adult dogs. This value was sufficiently reliable in terms of accuracy of determination and considered to be meaningful as the low level in vivo bioactivity that hasn't been known to date. Furthermore, erythropoietin levels in normal plasma were within a certain lower range and showed neither difference in plasma erythropoietin level between males and females or among breeds nor correlation between erythropoietin and hemoglobin level.

Endocrine cells and prognosis in patients with colorectal carcinoma

Using chromogranin (CG) immunohistochemical staining, the prognostic significance of endocrine differentiation was investigated in 212 patients with primary colorectal adenocarcinoma (including 6 patients with mucosal carcinoma). CG-immunoreactive cells were found to be an integral component of the tumor in 67 of 206 patients (32.5%, excluding mucosal carcinoma). The intracellular localization of CG in the CG-immunoreactive cells in cancer tissue was completely different from that in the normal endocrine cells of the large bowel. In addition, morphologic changes such as nuclear hyperchromasia and pleomorphism also indicated that the CG-immunoreactive cells in the cancer tissue were malignant. The tumors were divided into three groups based on the frequency of CG-immunoreactive cells: Group I (n = 139), negative; Group II (n = 38), less than 1 positive cell/mm2; and Group III (n = 29), more than 1 positive cell/mm2. No correlation was observed between CG-immunoreactivity (CG-IR) and tumor location, grade, depth of invasion, or stage, regardless of lymph node involvement. However, patients with numerous endocrine tumor cells (Group III) had a significantly worse prognosis compared with patients without endocrine cells (Group I) (multivariate Cox's model, P less than 0.01). Similar findings were observed in patients with node-negative tumor (multivariate Cox's model, P less than 0.05). These results indicated that the neuroendocrine differentiation is an independent prognostic factor and that CG-immunohistochemistry is useful for detecting a subgroup with a worse prognosis among patients with colorectal cancer.

[Effects of the synthetic proteinase inhibitor, FOY, on hypercoagulability after surgery for esophageal carcinoma]

Hypercoagulability develops after surgery for esophageal carcinoma, and it related closely to postoperative complications. This study evaluated the effects of the synthetic proteinase inhibitor, Cabexate Mesilate (FOY), on this hypercoagulability. The subjects used were 25 patients with a mean age of 63 who had undergone surgery for esophageal carcinoma. Of these, eight patients (test group) received FOY (2,000 mg/day) for three to 23 days after surgery, but 17 (control group) did not. In the test group, FOY controlled aggregation and release of the platelets and minimized their exhaustion. FOY almost completely checked the abnormal increase in thrombin activity which might trigger the hypercoagulability. Also, FOY suppressed the fibrinolytic activity slightly. These results indicate that FOY is effective in controlling hypercoagulability after surgery for esophageal carcinoma and in suppressing activity of the proteinases that cause both blood coagulation and fibrinolysis.

[Immunohistochemical and clinicopathological studies of chromogranin immunoreactive cells in large bowel carcinoma]

We examined the clinicopathological relevance of chromogranin immunoreactive cells in a well documented series of 212 large bowel cancer patients. Chromogranin immunoreactive cells were detected in 33.5% of the carcinomas, occurring either as rare cases (19.3%) or as diffuse cases (14.2%). The tumors with chromogranin immunoreactivity were associated with a more aggressive clinical course than tumors without immunoreactivity (Generalized-Wilcoxon; p less than 0.08). Moreover, the survival of patients with diffusely immunoreactive tumors was significantly shorter than that of patients without such cells (Generalized-Wilcoxon; p less than 0.009). Therefore, the study of chromogranin immunoreactivity in large bowel carcinomas may enable the identification of a subpopulation of colorectal carcinomas associated with a relatively poor prognosis.