Lower melatonin secretion in older females: gender differences independent of light exposure profiles.

BACKGROUND: Melatonin is associated with a variety of diseases in advanced age, including insomnia, depression, and dementia, and its secretion is influenced by light exposure. Although studies in young and middle-aged subjects have shown that females tend to have higher melatonin levels than males, gender differences in melatonin levels among older people remain unclear. METHODS: To determine the gender differences in melatonin levels among older people in home settings, we conducted a cross-sectional study in 528 older people. We measured overnight urinary 6-sulfatoxymelatonin excretion (UME; an index of melatonin secretion), and ambulatory light intensity. RESULTS: The mean age of females was 1.8 years younger, and average intensity of daytime light exposure was half that in males (P < 0.01). In a univariate comparison, UME was significantly lower in females than in males (P < 0.01). A multivariate model using analysis of covariance showed that log-transformed UME remained significantly lower in females after adjustment for potential confounding factors, including age and daytime and nighttime light exposure profiles (males vs. females: 1.90 vs. 1.73 log µg; adjusted mean difference 0.17 log µg [95% confidence interval [CI] 0.02-0.32]; P = 0.02). This result indicates that older females have 18.4% (95% CI, 2.2-37.4%) lower UME than older males. CONCLUSIONS: Older females have significantly lower UME than older males, an association which is independent of light exposure profiles in home settings. Our findings may be useful as basic data for further research to investigate gender differences in several diseases associated with melatonin in the elderly.

Development of gelatin flakes, a new type of anti-adhesive material: a preliminary study of in vivo rat adhesion models.

To overcome the problems associated with sheet- or film-type anti-adhesive materials, we developed a new type of anti-adhesive material, gelatin flakes. We made two types of gelatin flakes with or without thermal cross-linking, and preliminarily examined their basic properties and the anti-adhesive efficacy using a rodent adhesion model. Both types of the gelatin flakes rapidly turned into gel and tightly attached the injured surfaces, absorbing the moisture and blood, when applied onto the abraded sites of rats. In addition, these flakes could be sprayed into the desired area by compressed air through a device with a long, thin tube, which could be used in laparoscopic surgery. The anti-adhesive effects of both types of gelatin flakes were similar, and both types were significantly superior compared to the non-treated group. Although further investigations are necessary, the gelatin flakes have unique and useful properties and satisfactory anti-adhesive effects, which indicate that they may be applicable in laparoscopic surgery.

Selective induction of antimicrobial peptides from keratinocytes by staphylococcal bacteria.

Staphylococcus aureus (S. aureus) is one of the most clinically important inflammation-inducing pathogens, while Staphylococcus epidermidis (S. epidermidis) is nonpathogenic and hardly causes inflammation on skin. ß-defensins, antimicrobial peptides, are secreted from keratinocytes constitutively or upon induction by various microorganisms. However, the difference between S. aureus and S. epidermidis is still unclear in terms of their influences on the production of ß-defensins. In this study, we focused on the influences of S. aureus and S. epidermidis on the keratinocyte innate immune response. Pathogenic S. aureus mainly induced human ß-defensin (hBD) 1 and hBD3, but not hBD2, and nonpathogenic S. epidermidis mainly induced hBD2 from human keratinocytes. Molecular weight fractions of >10 kDa prepared from S. aureus supernatants induced the production of hBD1 and hBD3. On the other hand, molecular weight fraction of >100 kDa prepared from S. epidermidis supernatants induced the production of hBD2.Furthermore, the secreted products of S. epidermidis used the toll-like receptor (TLR) 2 pathway in the induction of hBD2 production. The secreted products of S. aureus and S. epidermidis differentially induced subtypes of hBD through different receptors, which may be associated with the difference in virulence between these two bacteria.

Novel pancreatoenteric reconstruction using a bioabsorbable polymer sheet and biocompatible bond.

BACKGROUND: Pancreatoenteric reconstruction often induces severe complications. Although many techniques have been developed to prevent these complications, no standard technique has yet emerged. We developed a novel technique, sutureless pancreatoenteric anastomosis, that uses a bioabsorbable polymer sheet (BAPS) and biocompatible bond (BCB) to prevent the complications associated with pancreatoenteric anastomosis. We used large animals to investigate whether this technique is suitable for clinical use. MATERIALS AND METHODS: Six pigs were laparotomized under general anesthesia. The body of the pancreas was divided, and the proximal stump was closed by suture. A BAPS coated with BCB was rolled and fixed around the distal pancreatic stump to form a cylinder that was anastomosed to the duodenum without suturing the pancreas. Twenty weeks after the initial operation the operated sites were extirpated and evaluated grossly and histologically. RESULTS: All operated pigs survived without pancreatic juice leakage until they were killed. At 20 wk, the BAPS could not be identified. The pancreatic stump was tightly affixed to the duodenum. Histologic study revealed that the pancreatic stump and duodenal wall were continuous and the main pancreatic duct opened into the lumen of the duodenum. CONCLUSIONS: Sutureless pancreatoenterostomy with BAPS and BCB may be clinically feasible.

Newly designed bioabsorbable substitute for the treatment of diaphragmatic defects.

PURPOSE: Earlier studies have investigated the suitability of various materials and autologous grafts for the repair of diaphragmatic defects. Our group investigated the feasibility of using an artificial diaphragm (AD) to repair wide diaphragmatic defects. METHODS: Twelve pigs were laparotomized and, in each pig, a defect was fashioned by resecting a round 8-cm diameter hole in the left diaphragm. Next, the defect was repaired by implanting an AD. The animals were relaparotomized 8 or 24 weeks after implantation for gross, histological and radiological observation of the implanted sites. RESULTS: All recipient animals survived until killing for evaluation. Chest X-ray examinations showed no differences between the preoperative diaphragms and the grafted diaphragms at 8 and 24 weeks after implantation. At 8 weeks after implantation, the implanted sites exhibited fibrous adhesions to the liver and lungs without deformities or penetrations. Parts of the surface tissue at the graft sites had a varnished appearance similar to those of the native diaphragm. Histology performed at 8 weeks detected no trace of the ADs in the graft sites; however, numerous inflammatory cells and profuse fibrous connective tissue were observed. At 24 weeks after implantation, no differences were found in the thorax between the areas with the grafts and the unaffected areas. Histology of the graft sites in the thorax confirmed growth of mesothelial cells similar to that observed in the native diaphragm. CONCLUSIONS: Artificial diaphragms can be a novel substitute for diaphragmatic repair.

Transplantation of induced pluripotent stem cell-derived neurospheres for peripheral nerve repair.

In spite of the extensive research using induced pluripotent stem (iPS) cells, the therapeutic potential of iPS cells in the treatment of peripheral nerve injury is largely unknown. In this study, we repaired peripheral nerve gaps in mice using tissue-engineered bioabsorbable nerve conduits coated with iPS cell-derived neurospheres. The secondary neurospheres derived from mouse iPS cells were suspended in each conduit (4000,000 cells per conduit) and cultured in the conduit in three-dimensional (3D) culture for 14 days. We then implanted them in the mouse sciatic nerve gaps (5 mm) (iPS group; n=10). The nerve conduit alone was implanted in the control group (n=10). After 4, 8 and 12 weeks, motor and sensory functional recovery in mice were significantly better in the iPS group. At 12 weeks, all the nerve conduits remained structurally stable without any collapse and histological analysis indicated axonal regeneration in the nerve conduits of both groups. However, the iPS group showed significantly more vigorous axonal regeneration. The bioabsorbable nerve conduits created by 3D-culture of iPS cell-derived neurospheres promoted regeneration of peripheral nerves and functional recovery in vivo. The combination of iPS cell technology and bioabsorbable nerve conduits shows potential as a future tool for the treatment of peripheral nerve defects.

Paradoxical gait at a narrowed entrance in a patient with Hoehn-Yahr stage III Parkinson's disease.

Recently, we studied fallers and non-fallers with Hoehn-Yahr stage III Parkinson's disease (PD) using a path that suddenly narrowed, which we originally designed and produced. A risk of future falls was suggested to be related to slow gait with freezing (SGF) elicited by a fear of falling before arrival at a narrowed entrance or while walking on a narrow path, as well as to the Unified Parkinson's Disease Rating Scale part II score, associated with SGF. In the same study, we had faller patients walk on a path that narrowed in a straight-line fashion to determine whether SGF could be improved. In one patient, who showed a unique paradoxical gait, SGF resolved. We describe this patient in the hope that our experience will provide potential clues to effective ways to prevent future falls in patients with Hoehn-Yahr stage III PD. To prevent gait instability elicited by fear of falling in patients with Hoehn-Yahr stage III PD, it might be useful to remove narrowed entrances.

Regeneration of extrahepatic bile ducts by tissue engineering with a bioabsorbable polymer.

With the widespread adoption of laparoscopic cholecystectomy and living-donor liver transplantation in recent years, complications involving the biliary system, stenosis in particular, are increasing. Various invasive and non-invasive techniques are now available for the treatment of biliary stenosis, but all are compromised by a high risk of recurrence and other problems. As a potential solution, our group has developed a bioabsorbable polymer (BAP) tube for implantation as a bypass graft. In the study reported here, we implanted this BAP tube and confirmed bile duct regeneration at the graft site after the tube had been degraded and absorbed into the body. We briefly describe our findings on extrahepatic biliary tissue regeneration, focusing on the possibility of its clinical application. This artificial bile duct may promote the development of novel treatments for biliary disease.

Pitfalls and promises of bile duct alternatives: A narrative review.

Biliodigestive anastomosis between the extrahepatic bile duct and the intestine for bile duct disease is a gastrointestinal reconstruction that abolishes duodenal papilla function and frequently causes retrograde cholangitis. This chronic inflammation can cause liver dysfunction, liver abscess, and even bile duct cancer. Although research has been conducted for over 100 years to directly repair bile duct defects with alternatives, no bile duct substitute (BDS) has been developed. This narrative review confirms our understanding of why bile duct alternatives have not been developed and explains the clinical applicability of BDSs in the near future. We searched the PubMed electronic database to identify studies conducted to develop BDSs until December 2021 and identified studies in English. Two independent reviewers reviewed studies on large animals with 8 or more cases. Four types of BDSs prevail: Autologous tissue, non-bioabsorbable material, bioabsorbable material, and others (decellularized tissue, 3D-printed structures, etc.). In most studies, BDSs failed due to obstruction of the lumen or stenosis of the anastomosis with the native bile duct. BDS has not been developed primarily because control of bile duct wound healing and regeneration has not been elucidated. A BDS expected to be clinically applied in the near future incorporates a bioabsorbable material that allows for regeneration of the bile duct outside the BDS.

Risk of falling in Parkinson's disease at the Hoehn-Yahr stage III.

BACKGROUND: It is difficult to predict the risk of falling, especially in patients with good motor ability, and the mechanisms underlying the relation between gait patterns and falling in Parkinson's disease (PD) remain unclear. We investigated factors related to falling, including walking speed and time, in patients with Hoehn-Yahr stage III PD. METHODS: We performed clinical assessments and evaluated balance in 30 patients with PD. Information on falling was obtained from questionnaires and personal interviews. Gait patterns were analyzed with the use of an originally designed, suddenly narrowed path. RESULTS: Gait velocity was slower in fallers than in non-fallers (p = 0.047). Unified Parkinson's Disease Rating Scale part II (UPDRS part II) score, fear of falling, and gait velocity were significantly related to falling on analysis with a single logistic model. When a multiple logistic model was used, the UPDRS part II score was significantly related to falling (OR: 1.48, p = 0.037, 95% CI: 1.02-2.16). CONCLUSIONS: Patients with Hoehn-Yahr stage III PD showed slow gait velocity attributed to fear of falling before arrival at a narrowed entrance or while walking on a narrowed path. The UPDRS part II score is significantly related to the risk of future falls.

Recovery Effects of a 180 mT Static Magnetic Field on Bone Mineral Density of Osteoporotic Lumbar Vertebrae in Ovariectomized Rats.

The effects of a moderate-intensity static magnetic field (SMF) on osteoporosis of the lumbar vertebrae were studied in ovariectomized rats. A small disc magnet (maximum magnetic flux density 180 mT) was implanted to the right side of spinous process of the third lumbar vertebra. Female rats in the growth stage (10 weeks old) were randomly divided into 4 groups: (i) ovariectomized and implanted with a disc magnet (SMF); (ii) ovariectomized and implanted with a nonmagnetized disc (sham); (iii) ovariectomized alone (OVX) and (vi) intact, nonoperated cage control (CTL). The blood serum 17-ß-estradiol (E(2)) concentrations were measured by radioimmunoassay, and the bone mineral density (BMD) values of the femurs and the lumbar vertebrae were assessed by dual energy X-ray absorptiometry. The E(2) concentrations were statistically significantly lower for all three operated groups than those of the CTL group at the 6th week. Although there was no statistical significant difference in the E(2) concentrations between the SMF-exposed and sham-exposed groups, the BMD values of the lumbar vertebrae proximal to the SMF-exposed area statistically significantly increased in the SMF-exposed group than in the sham-exposed group. These results suggest that the SMF increased the BMD values of osteoporotic lumbar vertebrae in the ovariectomized rats.

A new protease assay system using gelatin thin film for monitoring indoor air quality.

Airborne particulates have a major influence on the quality of indoor environments, which in turn affects human health. Both allergens and proteases are major etiological factors in allergic disease. Thus, the monitoring of environmental protease particulates is very important for the management of allergic disease. Protease-monitoring systems have been introduced in industry, but have not been applied to domestic settings, probably because of the high cost and many complex steps involved in these systems. In this study, we developed an indoor protease-monitoring system which can easily detect protease particulates without need for pre-treatment of dust samples or complex measuring instruments such as fluorescent plate reader. As a protease substrate, gelatin thin film (GTF) was adopted to evaluate small amounts of house dust particulates. The principle of this assay is based on the hydrolysis of GTF. Protease molecules spread from a particulate to GTF can hydrolyze the gelatin, thereby producing a spot on the GTF. This hydrolyzed spot visualized by staining was much larger than the particulate size, making visible to naked eye. The GTF method facilitated the observation of a subtle increase in protease particulates fallen on the GTF after the turnover of a used bed-quilt. The newly developed GTF method seems to be a suitable tool for protease monitoring at home.

Experimental repair of tracheal defect using a bioabsorbable copolymer.

BACKGROUND: We investigated epithelialization and newly formed cartilage in an artificial trachea constructed using a bioabsorbable copolymer. MATERIALS AND METHODS: Fifteen male Japanese white rabbits (2.5-2.8 kg) were divided into three groups. A full-thickness anterior defect (4 mm x 10 mm) was created in the trachea. The defect was implanted with one of the following bioabsorbable copolymers: caprolactone-lactide copolymer sponge sheet reinforced with poly(glycolic acid) fiber mesh (Cop) (n = 6, group A), Cop-incorporating gelatin hydrogel (n = 4, group B), and Cop-incorporating gelatin hydrogel with 100 microg of basic fibroblast growth factor (n = 5, group C). Each trachea was reinforced with an external nondegradable polymer stent. Three rabbits in each group were sacrificed at 1, 3, and 6 mo postoperatively and the trachea was evaluated histologically; other animals were sacrificed up to 12 mo postoperatively. RESULTS: In groups A, B, and C there were two, one, and one postoperative deaths, respectively. In group A, epithelialization was recognized from 1 mo to 12 mo postoperatively, but no new cartilage was formed during the 12 mo following implantation. In group B, epithelialization was recognized 3 and 6 mo postoperatively, and new cartilage was detected at 6 mo after the operation. In group C, newly formed cartilage and epithelialization were observed 3, 6, and even 12 mo postoperatively. Furthermore, neovascularization was observed in groups B and C. CONCLUSIONS: A bioabsorbable copolymer incorporating gelatin hydrogel induces tracheal epithelialization and formation of cartilage and vessels in tracheal defects, and could be available for clinical use in children.

A newly developed degradable stent for pancreaticojejunostomy after pancreatoduodenectomy.

A novel technique of anastomosis with a short-term degradable stent for pancreaticojejunostomy has been developed and its shape-retentive capability evaluated under conditions of exposure to digestive fluid and its clinical feasibility. The stent was braided manually using Monocryl and PDS-II of 2-0 wire and heat treated at 80 degrees C for 3 hours under a vacuum. We measured its maximum resistance to compression strength and elastic modules of the stent. We evaluated the feasibility of the stent in 8 patients under pancreaticojejunostomy and hepaticojejunostomy. The compression strength of the stent was preserved for about 3 weeks, after which point it collapsed. The elastic features were retained under exposure to gastric fluid, but they were lost under an intestinal juice exposure. Using this stent, "suturing of tissue with the stent on" was possible as a novel technique of anastomosis and induced few complications.

Tissue engineering a model for the human ear: assessment of size, shape, morphology, and gene expression following seeding of different chondrocytes.

This study examines the tissue engineering of a human ear model through use of bovine chondrocytes isolated from four different cartilaginous sites (nasoseptal, articular, costal, and auricular) and seeded onto biodegradable poly(l-lactic acid) and poly(L-lactide-epsilon-caprolactone) (50 : 50) polymer ear-shaped scaffolds. After implantation in athymic mice for up to 40 weeks, cell/scaffold constructs were harvested and analyzed in terms of size, shape, histology, and gene expression. Gross morphology revealed that all the tissue-engineered cartilages retained the initial human auricular shape through 40 weeks of implantation. Scaffolds alone lost significant size and shape over the same period. Quantitative reverse transcription-polymerase chain reaction demonstrated that the engineered chondrocyte/scaffolds yielded unique expression patterns for type II collagen, aggrecan, and bone sialoprotein mRNA. Histological analysis showed type II collagen and proteoglycan to be the predominant extracellular matrix components of the various constructs sampled at different implantation times. Elastin was also present but it was found only in constructs seeded with auricular chondrocytes. By 40 weeks of implantation, tissue-engineered cartilage of costal origin became calcified, marked by a notably high relative gene expression level of bone sialoprotein and the presence of rigid, nodular protrusions formed by mineralizing rudimentary cartilaginous growth plates. The collective data suggest that nasoseptal, articular, and auricular cartilages represent harvest sites suitable for development of tissue-engineered human ear models with retention over time of three-dimensional construct architecture, gene expression, and extracellular matrix composition comparable to normal, nonmineralizing cartilages. Calcification of constructs of costal chondrocyte origin clearly shows that chondrocytes from different tissue sources are not identical and retain distinct characteristics and that these specific cells are inappropriate for use in engineering a flexible ear model.

Inhibitory effects of a biodegradable gelatin hydrogel sponge sheet on the progression of experimental abdominal aortic aneurysms.

We investigated the effects of a biodegradable gelatin hydrogel sponge sheet (GHSS) or GHSS incorporating basic fibroblast growth factor (GHSS + bFGF), which could prolong the effects of bFGF, on the progression of experimental abdominal aortic aneurysms (AAAs). Experimental AAAs were induced in male Sprague-Dawley rats by intra-aortic elastase infusion. The rats were divided according to the following treatments: (1) untreated, (2) GHSS alone, (3) GHSS incorporating 100 ng, 1 microg, and 10 microg of bFGF. GHSSs were placed over the elastase-infused aortas. After 14 days, the GHSS alone group and the three groups with GHSS + bFGF demonstrated significantly smaller aortic diameters than the untreated group, and these groups significantly attenuated a reduction of the elastic fibers and smooth muscle cells in the pathological findings. However, no additional therapeutic effect was noted between the GHSS alone and GHSS + bFGF groups. Immunohistochemical analysis revealed an increase of positive cells for endogenous bFGF in the media and adventitia of both the GHSS alone and GHSS + bFGF groups in comparison to the untreated group. In conclusion, GHSS itself possessed significant therapeutic effects on AAA progression by inducing the production of endogenous bFGF, leading to the preservation of elastic fibers and smooth muscle cells.

Evaluation of a poly(L-lactic acid) stent for sutureless vascular anastomosis.

We have developed a sutureless anastomosis device consisting of a biodegradable stent and stainless steel band for end-to-end anastomosis. The aim of this acute phase study was to evaluate the feasibility of a sutureless anastomotic procedure with a bioabsorbable stent during a 4-week period in a swine model. The porcine infrarenal aorta was replaced with an expanded polytetrafluoroethylene graft. A proximal anastomosis was completed using a sutureless anastomotic procedure employing a bioabsorbable stent made of poly(L-lactic acid) (PLLA) and a stainless steel plate. A distal anastomosis completed by manual suturing served as a control. At 4 weeks after surgery, angiography was performed. The animals were then killed, and the specimens were evaluated histologically. The sutureless anastomotic procedure required significantly less time than the suturing technique. Angiograms showed patency of the grafts, and no signs of either stenosis or leakage. Both pressure-proof and tensile tests confirmed the adequate mechanical strength of the anastomoses. Sutureless anastomosis with a PLLA stent appears to be feasible, at least within an observation period of 4 weeks. This simple procedure shortened the time of surgery and would contribute to reducing the risks of operation-related complications.

Forty years of the Japanese Society for Biomaterials looking back at my term of office as the chairperson.

The compatibility of artificial materials with living system, such as antithrombogenicity and antiimmunogenicity, has been an important issue in the field of the biomaterials researches at the early periods of the biomaterials research. After that, the bioabsorbable materials have been subsequently incorporated as biomaterials. As a result, biomaterial researchers started participating in the field of drug delivery system (DDS), and combining biomaterials and cells not only led to bioartificial organs, but also tissue engineering. The bioabsorbable biomaterials function as scaffolds for the cells and play an important role in the field of regenerative medicine researches. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 930-932, 2019.

Effect of covering with cross-linked gelatin glue on tissue regeneration in a rat lung injury model.

OBJECTIVES: Thoracic reintervention is a common treatment; however, preventing adhesion of the lung to the thoracic cavity wall remains a problem. This study aimed to investigate the effect on pleural adhesion of covering the postoperative pleural injury site with cross-linked gelatin glue (gelatin plus glutaraldehyde, hereafter 'gelatin glue') and to evaluate the proliferation of healing cells on gelatin glue. METHODS: We created a rat incisional lung-wound model and compared the effects of sealing the wound with gelatin glue (group A, n = 5), fibrin glue (group B, n = 5) or fibrin glue with a polyglycolic acid sheet (group C, n = 5). Adhesions were assessed 28 days postoperatively and compared among the groups using the Karacam's scoring method. Lung-wound healing was studied histologically at day 7 postoperatively. Mesothelial cell proliferation was investigated on gelatin and fibrin glues in vitro. RESULTS: There were no or few adhesions of the chest wall in group A. The adhesion scores (mean ± standard deviation) were 1.2 ± 0.4, 2.6 ± 1.4 and 3.2 ± 1.2 in groups A, B and C, respectively (A vs C, P = 0.0496). During the healing process, the gelatin glue surface was covered by mesothelial-like cells. Proliferation of cultured mesothelial cells was promoted on the gelatin glue compared with the fibrin glue. CONCLUSIONS: Covering lung wounds with the gelatin glue reduced adhesions and promoted the growth of healing cells compared with the fibrin glue. These findings suggest that the gelatin glue may help prevent adhesions and thus be a therapeutically effective biomaterial in lung surgery.

Spatial gradient effects of 120 mT static magnetic field on endothelial tubular formation in vitro.

This study investigated the spatial magnetic gradient effects of static magnetic fields (SMF) on endothelial tubular formation by applying the maximum spatial gradient to a target site of culture wells for cell growth. The respective maximum values of magnetic flux density (B(max)), magnetic flux gradient (G(max)) and the magnetic force product of the magnetic flux density and its gradient (a parameter of magnetic force) were 120 mT, 28 mT/mm and 1428 mT(2)/mm. The effects of gradient SMF on tubular formation were compared with those of uniform SMF that has no spatial gradients on the entire bottom area of culture wells. Five experimental groups of 25 samples each were examined: (1) sham exposure (control); (2) peak gradient exposure in the peripheral part; (3) peak gradient exposure in the central part; (4) uniform exposure to 20 mT; (5) uniform exposure to 120 mT. The SMF or sham exposure was carried out for 10 days. Photomicrographs of tubular cells, immunostained with an anti-platelet-endothelial cell adhesion molecule-1 (PECAM-1 [CD31]) antibody as a pan-endothelial marker, were analyzed after the 10-day culture. Gradient SMF in the peripheral or central part was found to significantly promote tubular formation in terms of the area density and length of tubules in each peak gradient/force part of the wells, compared with the sham exposure. In contrast, uniform SMF did not induce any significant change in the tubular formation. These findings suggest that tubule formation can be promoted by applying the peak gradient/force to a target site of culture wells.