Romosozumab treatment in postmenopausal women with osteoporosis: a meta-analysis of randomized controlled trials

AIM

To conduct a systematic review and meta-analysis of randomized controlled trials (RCTs) to evaluate the safety and efficacy of romosozumab in the treatment of postmenopausal osteoporosis.

METHOD

A comprehensive literature review was performed of PubMed, EMBASE, Cochrane Controlled Trials Registry, and Web of Science for RCTs. Outcome measures were changes in lumbar spine, total hip and femoral neck bone mineral density (BMD), incidence of fractures and adverse events. Six trials were finally included.

RESULTS

Romosozumab resulted in a significantly lower risk of new vertebral fracture (relative risk (RR) 0.37, 95% confidence interval (CI) 0.18-0.77, p = 0.005, n = 5371), non-vertebral fracture (RR 0.78, 95% CI 0.66-0.92, p < 0.0001, n = 5635) and hip fracture (RR 0.59, 95% CI 0.44-0.79, p = 0.0004, n = 5635) compared with other therapies. The BMD was significantly increased at the lumbar spine (weighted mean difference (WMD) 13.33, 95% CI 11.41-15.25, p < 0.00001, n = 198), total hip (WMD 5.09, 95% CI 3.81-6.38, p < 0.00001, n = 184) and femoral neck (WMD 4.70, 95% CI 3.50-5.90, p < 0.00001, n = 175) compared with placebo. There was no significant difference in the incidence of adverse events in patients with romosozumab compared to other therapies (RR 1.00, 95% CI 0.98-1.02).

CONCLUSION

In postmenopausal women with osteoporosis who were at high risk for fracture, romosozumab treatment resulted in a significantly lower risk of fracture. Romosozumab 210 mg monthly showed the largest gains in BMD, and was generally well tolerated.

Urban landscape genomics identifies fine-scale gene flow patterns in an avian invasive

Invasive species exert a serious impact on native fauna and flora and have been the target of many eradication and management efforts worldwide. However, a lack of data on population structure and history, exacerbated by the recency of many species introductions, limits the efficiency with which such species can be kept at bay. In this study we generated a novel genome of high assembly quality and genotyped 4735 genome-wide single nucleotide polymorphic (SNP) markers from 78 individuals of an invasive population of the Javan Myna Acridotheres javanicus across the island of Singapore. We inferred limited population subdivision at a micro-geographic level, a genetic patch size (~13-14 km) indicative of a pronounced dispersal ability, and barely an increase in effective population size since introduction despite an increase of four to five orders of magnitude in actual population size, suggesting that low population-genetic diversity following a bottleneck has not impeded establishment success. Landscape genomic analyses identified urban features, such as low-rise neighborhoods, that constitute pronounced barriers to gene flow. Based on our data, we consider an approach targeting the complete eradication of Javan Mynas across Singapore to be unfeasible. Instead, a mixed approach of localized mitigation measures taking into account urban geographic features and planning policy may be the most promising avenue to reducing the adverse impacts of this urban pest. Our study demonstrates how genomic methods can directly inform the management and control of invasive species, even in geographically limited datasets with high gene flow rates.

Mechanism of sodium hydrosulfide modulation of L-type calcium channels in rat colonic smooth muscle cells

Hydrogen sulfide (H₂S) can exert different effects on the gastrointestinal tract by modulating ion channels. Previously, we found that H₂S donor sodium hydrosulfide (NaHS) regulates colonic motility through L-type calcium channels, but the molecular mechanism remains unknown. The present study was designed to investigate possible mechanisms underlying the modulation of L-type calcium channels by NaHS in rat colonic smooth muscle cells. L-type calcium currents in colonic smooth muscle cells were recorded using the whole-cell patch-clamp technique. Spontaneous contractions of mid-colonic smooth muscle strips were measured in an organ bath system and a biological signal acquisition system. NaHS evoked a significant rightward shift in the steady-state activation curve of L-type calcium channels, changed the shape of the current-voltage (I-V) curve, and decreased the peak current density at 0mV, although it significantly increased with higher stimulatory voltage. The sulfhydryl-modifying reagent DL-dithiothreitol (DTT) enhanced the effects of NaHS on L-type calcium channels, while diamide (DM) and reduced L-glutathione (GSH) alleviated the effects of NaHS. Additionally, NaHS inhibited the spontaneous high-amplitude contractions of both longitudinal and circular smooth muscle strips in a dose-dependent manner. The inhibitory effects were reversible. DTT and GSH enhanced the effects of NaHS, while DM attenuated the effects of NaHS. In conclusion, NaHS modulates L-type calcium channels in rat colonic smooth muscle cells and regulates the contractile activity of colonic smooth muscle, potentially by modifying the free sulfhydryl groups of L-type calcium channels.

Experimental study on repairing skin defect by tissue-engineered skin substitute compositely constructed by adipose-derived stem cells and fibrin gel

OBJECTIVE

To study the application value of artificial skin substitute compositely constructed by adipose-derived stem cells and fibrin gel in skin defect.

MATERIALS AND METHODS

Adipose-derived stem cells (ADSCs) were obtained from healthy pure green fluorescent protein (GFP) transgenic mice and were proved to have multiple differentiation potentials. They compositely constructed artificial skin substitute in vitro with fibrin gel. 24 SD rats of either gender, with the gestational age of 3-5 weeks, were divided into four groups in the experiment, namely model group (autologous skin flap transplantation), adipose-derived stem cell transplantation group, fibrin gel transplantation group and compound transplantation group, 6 rats for each group. At the skin blood flow (measured by applying laser Doppler rheometer) and survival rate of the flap on 7d and 21d respectively, the materials were transplanted at back skin injury (1 cm×1 cm) to prepare tissue slice for routine HE staining. The conditions of wound healing were observed, and the angiogenesis of flap neovascularization was detected by the immunofluorescent assay.

RESULTS

The skin blood flow, the survival rate of flap and density of neovascularization 7d and 21d after transplantation were significantly higher than those of stem cell group, followed by the model group, with the lowest ones in the fibrin gel group. The differences had statistical significance (p<0.05). The wound healing time of compound group was significantly shorter than that of stem cell group, followed by the model group, with the longest one in the fibrin gel group. The differences had statistical significance (p<0.05).

CONCLUSIONS

The artificial skin substitute compositely constructed by adipose-derived stem cells and fibrin gel could significantly shorten healing time and improve the survival rate of the flap in skin defect, with better application value.

Neutron Generation by Laser-Driven Spherically Convergent Plasma Fusion

We investigate a new laser-driven spherically convergent plasma fusion scheme (SCPF) that can produce thermonuclear neutrons stably and efficiently. In the SCPF scheme, laser beams of nanosecond pulse duration and 10^{14}-10^{15}  W/cm^{2} intensity uniformly irradiate the fuel layer lined inside a spherical hohlraum. The fuel layer is ablated and heated to expand inwards. Eventually, the hot fuel plasmas converge, collide, merge, and stagnate at the central region, converting most of their kinetic energy to internal energy, forming a thermonuclear fusion fireball. With the assumptions of steady ablation and adiabatic expansion, we theoretically predict the neutron yield Y_{n} to be related to the laser energy E_{L}, the hohlraum radius R_{h}, and the pulse duration τ through a scaling law of Y_{n}∝(E_{L}/R_{h}^{1.2}τ^{0.2})^{2.5}. We have done experiments at the ShengGuangIII-prototype facility to demonstrate the principle of the SCPF scheme. Some important implications are discussed.

[Efficacy and safety of tertiary hospital guided and community-driven family self-help cardiac rehabilitation model]

Objective: To explore the efficacy and safety of tertiary hospital guided and community-driven family self-help cardiac rehabilitation model. Methods: This study was a prospective randomized controlled study, 80 patients from Beijing Electrical Power Hospital and Beijing Jingmei Group General Hospital with acute coronary syndrome were included from June to December 2015 and divided into 2 groups. Patients in rehabilitation group (n=52) received tertiary hospital(Peiking University Peoples' Hospital) guided and community-driven family self-help cardiac rehabilitation for 3 months, and patients in control group (n=28) received routine secondary treatment for 3 months. Following parameters including 6 minutes walk distance, score of life quality (evaluated by Short Form-12), score of anxiety (evaluated by Generalized Anxiety Disorder-7), score of depression (evaluated by Perceived Health Questionnaire-9), self-management competency (evaluated by questionnaire) were collected at baseline and after treatment for 3 months. Results: Compared with control group, 6 minutes walk distance was longer in rehabilitation group((60.2±6.8) meters vs. (24.9±10.5)meters, P<0.01). The difference values between after and before intervention of life quality scores((0.14±3.90)scores vs.(-7.44±5.85)scores, P>0.05), anxiety scores((-0.16±2.12 ) scores vs.(0.70±1.13)scores, P>0.05) and depression scores((-1.17±2.79) scores vs.(0.60±0.36)scores, P>0.05) were similar between the 2 groups. The amplification of patients with regular exercise (50.26% vs. 0, P<0.05), limit sugary foods usually and always (53.22% vs. 3.98%, P<0.05), eat 200-400 g fruits usually and always (78.61 % vs. 0, P<0.05), eat 300-500 g vegetables usually and always (9.74% vs. 0, P<0.05), and answering very confident to questions such as let the physicians know about your diseases (40.17% vs. 5.00%, P<0.05), know how to take medicines (44.52% vs. 5.00%, P<0.05), know how much exercise was right for yourself (26.43% vs.0, P<0.05) were significantly higher in rehabilitation group than in control group. There were no cardiac rehabilitation training related cardiovascular events. Conclusion: Tertiary hospital guided and community-driven family self-help cardiac rehabilitation model is an effective and safe management model of cardiovascular disease in chronic phase, and it is necessary to further expand the study population to verify the efficacy of this model.

Prostaglandin E2 regulates renal function in C57/BL6 mouse with 5/6 nephrectomy

AIMS

To investigate the roles of cyclooxygenases (COX) and their metabolites in C57/BL6 mice with 5/6 nephrectomy, an animal model of chronic renal failure.

MAIN METHODS

C57/BL6 mice were grouped into sham-operated (2K), one kidney removal (1K) and 5/6 nephrectomy groups (5/6Nx). Renal resistive index was measured by ultrasonography. Blood, aortae, renal arteries and renal cortex were collected for measurement of kidney function, assessment of vascular responsiveness, Western blotting, immuohistochemistry and enzyme-linked immunosorbent assays.

KEY FINDINGS

After four weeks, acetylcholine-induced relaxations were blunted in renal arteries of 1K and 5/6Nx mice; indomethacin, a non-selective COX inhibitor, improved the response in 5/6Nx, but not in 1K renal arteries. In 5/6Nx renal arteries, but not in 1K preparations, the protein presence of endothelial nitric oxide synthase (eNOS) was decreased, while that of COX-2 and its products [prostacyclin and thromboxane A₂] were increased. The renal resistive index was lower in 5/6Nx mice, suggesting a lower resistance in the renal microvasculature. In the renal cortex of 5/6Nx mice, eNOS protein presence was increased; while the presence of COX-2 was not detectable. The prostaglandin E₂ level was lower in the 5/6Nx cortex than in the other two groups.

SIGNIFICANCE

The early stage of renal mass removal is associated with increased renal arterial constriction and reduced microvascular resistance. The former is due to downregulation of eNOS and upregulation of COX-2, leading to an increased production of prostacyclin and thromboxane A₂. A reduced production of PGE₂ in the renal cortex is important for maintaining normal renal function.

Interfacial rheology of coexisting solid and fluid monolayers

Biologically relevant monolayer and bilayer films often consist of micron-scale high viscosity domains in a continuous low viscosity matrix. Here we show that this morphology can cause the overall monolayer fluidity to vary by orders of magnitude over a limited range of monolayer compositions. Modeling the system as a two-dimensional suspension in analogy with classic three-dimensional suspensions of hard spheres in a liquid solvent explains the rheological data with no adjustable parameters. In monolayers with ordered, highly viscous domains dispersed in a continuous low viscosity matrix, the surface viscosity increases as a power law with the area fraction of viscous domains. Changing the phase of the continuous matrix from a disordered fluid phase to a more ordered, condensed phase dramatically changes the overall monolayer viscosity. Small changes in the domain density and/or continuous matrix composition can alter the monolayer viscosity by orders of magnitude.

[Analysis of the therapeutic effects of different treatment modalities on the outcomes of 87 patients with lung oligometastasis from nasopharyngeal carcinoma after radiotherapy]

OBJECTIVE

The aim of the present study was to evaluate the efficacy of three different modalities in treatment of lung oligometastases from nasopharyngeal carcinoma (NPC) after radiotherapy and to identify a more appropriate treatment modality.

METHODS

The clinical data of 87 cases of lung oligometastases from NPC were analyzed retrospectively. Among them, 33 patients underwent local small-field irradiation+ /- chemotherapy, 28 underwent whole-lung irradiation+ chemotherapy, and 26 underwent simple chemotherapy. The survival rates were calculated using Kaplan-Meier analysis. The differences among the modalities were evaluated using the log-rank test. Cox univariate and multivariate analyses were performed to determine the influencing factors.

RESULTS

The 3-year lung metastasis survival (LMS) rates of patients with lung metastasis undergoing the three treatment modalities (local small-field irradiation+ /-chemotherapy, whole-lung irradiation+ chemotherapy and chemotherapy alone) were 89.3%, 72.7%, and 72.4%, respectively, showing a significant difference between the groups (P=0.003). Further subgroup analysis showed that the 5-year LMS rate was significantly higher in the local small-field irradiation+ /-chemotherapy group than that in the whole-lung irradiation+ chemotherapy group and chemotherapy alone group (P=0.001). The 2-year progression-free survival (PFS) rates of the three groups were 57.1%, 25.8% and 3.8%, respectively, showing significant intergroup differences (P=0.002 and P<0.001). Multivariate analysis indicated that compared with the whole lung irradiation group and the chemotherapy alone group, the local irradiation+ /- chemotherapy is an independent favorable prognostic factor for LMS and PFS (P<0.05).

CONCLUSION

Local radiotherapy combined with systemic chemotherapy is the best therapeutic modality for lung oligometastases derived from NPC after radiotherapy, improving the LMS and prolonging the PFS.

[Prognostic factors of patients with T3N0M0 renal cell carcinoma: a single-center retrospective study of 182 patients]

OBJECTIVE

To evaluate the impacts of clinical, pathological, and laboratory factors on oncological outcomes of patients with T3N0M0 renal cell carcinoma.

METHODS

The clinical data, laboratory exam results, and follow-up outcomes of 182 patients with T3N0M0 renal cell carcinoma who underwent nephrectomy from 2007 to 2012 in Peking University First Hospital were retrospectively collected. The 5-year cancer-specific survival and 5-year recurrence-free survival of all the patients were calculated using Kaplan-Meier method, and the statistical significance between the survival curves were compared using the Log-rank test. Variables with significant differences in the univariate analysis were subjected to the multivariate analysis by Cox regression model. All the comparisons were conducted using two-tailed test and P<0.05 was considered statistically significant.

RESULTS

A total of 182 patients were included in this study. Of all the 182 patients, 126 were male (69.23%) and 56 were female (30.77%). The mean age was (56.75±12.45) years. The median follow-up time was 48 months (3-99 months). At the end of the follow-up, 50 patients (27.47%) died due to the disease after a median of 29.74 months and 59 patients (32.42%) had tumor recurrence after a median of 22.12 months. The 5-year cancer-specific survival of all patients was 68.30% (95% CI: 60.16%-75.84%); the 5-year recurrence-free survival was 60.70% (95% CI: 53.16%-68.84%). In the univariate analysis, diabetes mellitus, tumor invasion status, Fuhrman grade, serum album, serum cholestenone, anemia, and neutrophils percentage were associated with the cancer-specific survival and Fuhrman grade, serum album and anemia were associated with the recurrence-free survival. Variables with significant differences on univariate analysis were included in Cox multivariate regression analysis. Multivariate Logistic regression analysis showed that diabetes mellitus (HR=2.434, 95% CI: 1.243-4.769, P=0.010), hypoalbuminemia (HR=2.188, 95% CI: 1.074-1.074, P=0.031), and anemia (HR=3.320, 95% CI: 1.839-5.991, P<0.001) were independent risk factors significantly associated with cancer-specific survival; and higher Fuhrman grade (HR=2.552, 95% CI: 1.433-4.545, P=0.001), anemia (HR=2.535, 95% CI: 1.497-4.293, P=0.001) were independent factors significantly associated with recurrence-free survival.

CONCLUSION

Diabetes mellitus, hypoalbuminemia, and anemia were independent risk factors significantly associated with cancer-specific survival of T3N0M0 renal cell carcinoma patients; higher Fuhrman grade and anemia were independent risk factors significantly associated with tumor recurrence of T3N0M0 renal cell carcinoma patients.

[Methylation status of RASSF1A gene promoter in upper tract urothelial carcinoma and its clinical significance]

OBJECTIVE

To investigate the methylation status of the RASSF1A gene promoter in upper tract urothelial carcinoma (UTUC) tissues and its correlation with clinicopathologic characteristics and postoperative recurrence of primary UTUC.

METHODS

In a retrospective design, a total of 687 patients who underwent surgeries for primary UTUC in the urology department of Peking University First Hospital were enrolled. The methylation status of the RASSF1A gene promoter was analyzed using methylation-sensitive polymerase chain reaction on tumor specimens.

RESULTS

Aberrant methylation for the RASSF1A gene promoter was detected in 183 (26.6%) DNA samples in total. Aberrant methylation of the RASSF1A gene was strongly associated with tobacco consumption (P=0.044), ipsilateral hydronephrosis (P<0.001 ), tumor location (P<0.001 ), tumor stage (P=0.001), tumor grade (P=0.007), lymph node metastasis (P=0.001) and growth pattern (P=0.013). The methylated RASSF1A gene promoter was an independent risk factor for bladder recurrence (P<0.001, HR=0.471) and contralateral recurrence (P=0.030, HR=0.269) of UTUC after surgery. Hypermethylated RASSF1A was predictive for improved bladder recurrence-free survival (BRFS) (P<0.001) and contralateral recurrence-free survival (CRFS) (P=0.021) in the UTUC patients. Compared with the patients with unmethylated RASSF1A, the patients containing tumors with hypermethylated RASSF1A had tendency toward longer recurrence-free survival time [(114.4±3.9) months vs. (84.0±3.2) months for BRFS, (138.1±1.8) months vs. (132.9±1.9) months for CRFS] and higher estimated cumulative recurrence-free survive rates ( five-year survival rate for example, 79.8%±3.4% vs. 57.4%±2.6% for BRFS, 98.9%±0.8% vs. 93.0%±1.4% for CRFS). Additionally, tumor multifocality (P=0.002, HR=1.538), and ureteroscopy before surgery (P=0.001, HR=1.725) were independent risk factors for bladder recurrence in postoperative UTUC patients.

CONCLUSION

The methylation status of the RASSF1A gene promoter appears to be a promising epigenomic biomarker for assessing the aggressiveness of UTUC and a predictor predicting the urinary tract recurrence after surgery.

Preoperative ropivacaine with or without tramadol for femoral nerve block in total knee arthroplasty

PURPOSE

To compare the analgesic effect of preoperative ropivacaine with or without tramadol for femoral nerve block in total knee arthroplasty (TKA).

METHODS

14 men and 46 women aged 59 to 80 years who were American Society of Anesthesiologists (ASA) grade I or II and were scheduled for TKA were randomised to receive preoperative femoral nerve block with 20 ml of 0.375% ropivacaine plus tramadol 0 mg (n=15), 50 mg (n=15), or 100 mg (n=15), or no preoperative femoral nerve block (control) [n=15]. Femoral nerve block was performed by a single anaesthesiologist before the standardised combined spinal epidural anaesthesia. Postoperatively, patientcontrolled analgesia was given. The visual analogue score (VAS) for pain at rest and on movement was recorded at 8, 12, 24, 48, and 72 hours. Passive knee range of motion (ROM) was measured at 24, 48, and 72 hours.

RESULTS

The 4 groups were comparable in terms of age, gender, weight, ASA grade, and operating time. Compared with patients who received no femoral nerve block or ropivacaine alone, those who received femoral nerve block with 20 ml of 0.375% ropivacaine plus tramadol 50 mg or 100 mg recorded a lower VAS for pain at rest and on movement at 8 to 72 hours, longer sensory and motor block time, and lower demand, delivery, and total amount of patientcontrolled analgesia. The passive knee ROM at 24 to 72 hours was greater in patients with femoral nerve block than in those without.

CONCLUSION

Preoperative femoral nerve block with 20 ml of 0.375% ropivacaine and 100 mg tramadol resulted in the best analgesic effect.

Identification of Natural Infections in Sheep/Goats with HoBi-like Pestiviruses in China

The natural infections of HoBi-like pestiviruses in cattle have been reported in South America, Europe and Asia. In China, although the detections of HoBi-like pestivirus have been reported, the epidemiological investigation was limited. From January 2014 to October 2015, several flocks of sheep/goats in Henan province in central China suffered respiratory diseases which were recovered slowly after antibiotics treatment. To test whether it is the HoBi-like pestivirus caused this symptom, 49 serum samples and 22 nasal swabs were then collected for analysis by serology and RT-PCR. Serological result revealed that prevalence of pestivirus in small ruminants was 12.2% (6/49) in central China. Sequence analysis of partial 5'-UTR nucleotides of pestivirus-positive samples suggested that HoBi-like pestivirus might have circulated in sheep/goats of China for a period and have evolved into new genotype clusters. It is apparent that the study provides the molecular evidence of natural infections in goat/sheep species with HoBi-like pestiviruses in China.

eNOS gene T786C, G894T and 4a4b polymorphisms and male infertility susceptibility: a meta-analysis

The association between polymorphism of eNOS and male infertility in several studies was controversial. To explore a more precise estimation of the association, a meta-analysis of eight case-control studies, including 1,968 cases and 1,539 controls, were selected. The meta-analysis was conducted by calculating the pooled odds ratio (OR) with a 95% confidence interval (95% CI). Overall, the association between T786C and risk of male infertility was obvious (TC vs. TT: OR, 1.20; 95% CI, 1.01-1.42; CC vs. TT: OR, 3.37; 95% CI, 1.65-6.87; TC/CC vs. TT: OR, 1.47; 95% CI, 1.25-1.73; CC vs.

TT/TC

OR, 3.18; 95% CI, 1.54-6.56; TC vs. TT: OR, 1.65; 95% CI, 1.27-2.03). However, no overall association was observed between the other two polymorphisms of eNOS (G894T and 4a4b) and male infertility. Stratified analysis showed that significantly strong association between T786C polymorphism and semen quality was present in all three types of male infertility (azoospermia, oligozoospermia and asthenozoospermia). In the subgroup analysis based on ethnicity, both T786C and 4a4b could influence the risk of male infertility in Asian and Caucasian. Further studies of polymorphisms of eNOS with their biological functions are needed to understand the role in the development of male infertility.

Evaluation of tumour vascular distribution and function using immunohistochemistry and BOLD fMRI with carbogen inhalation

AIM

To evaluate oxygenation changes in rat subcutaneous C6 gliomas using blood-oxygen-level dependent (BOLD) functional magnetic resonance imaging (fMRI) combined with non-haemodynamic response function (non-HRF) analysis.

MATERIALS AND METHODS

BOLD fMRI were performed during carbogen inhalation in 20 Wistar rats bearing gliomas. Statistical maps of spatial oxygenation changes were computed by a dedicated non-HRF analysis algorithm. Three types of regions of interest (ROIs) were defined: (1) maximum re-oxygenation zone (ROI_max), (2) re-oxygenation zones that were less than the maximum re-oxygenation (ROI_non-max), and (3) zones without significant re-oxygenation (ROI_none). The values of percent BOLD signal change (PSC), percent enhancement (ΔSI), and significant re-oxygenation (T) were extracted from each ROI. Tumours were sectioned for histology using the fMRI scan orientation and were stained with haematoxylin and eosin and CD105. The number of microvessels (MVN) in each ROI was counted. Differences and correlations among the values for T, PSC, ΔSI, and MVN were determined.

RESULTS

After carbogen inhalation, the PSC significantly increased in the ROI_max areas (p<0.01) located in the tumour parenchyma. No changes occurred in any of the ROI_none areas (20/20). Some changes occurred in a minority of the ROI_non-max areas (3/60) corresponding to tumour necrosis. MVN and PSC (R=0.59, p=0.01) were significantly correlated in the ROI_max areas. In the ROI_non-max areas, MVN was significantly correlated with PSC (R=0.55, p=0.00) and ΔSI (R=0.37, p=0.00).

CONCLUSIONS

Statistical maps obtained via BOLD fMRI with non-HRF analysis can assess the re-oxygenation of gliomas.

The role of substance P in the maintenance of colonic hypermotility induced by repeated stress in rats

BACKGROUND

The mechanism underlying chronic stress-induced gastrointestinal (GI) dysmotility has not been fully elucidated and GI hormones have been indicated playing a role in mediating stress-induced changes in GI motor function.

AIMS

Our objective was to study the possible role of substance P (SP) in the colonic hypermotility induced by repeated water avoidance stress (WAS) which mimics irritable bowel syndrome.

METHODS

Male Wistar rats were submitted to WAS or sham WAS (SWAS) (1h/day) for up to 10 consecutive days. Enzyme Immunoassay Kit was used to detect the serum level of SP. The expression of neurokinin-1 receptor (NK1R) was investigated by Immunohistochemistry and Western blotting. The spontaneous contraction of muscle strip was studied in an organ bath system. L-type calcium channel currents (ICa,L) of smooth muscle cells (SMCs) were recorded by whole-cell patch-clamp technique.

RESULTS

Fecal pellet expulsion and spontaneous contraction of proximal colon in rats were increased after repeated WAS. The serum level of SP was elevated following WAS. Immunohistochemistry proved the expression of NK1R in mucosa, muscularis and myenteric plexus. Western blotting demonstrated stress-induced up-regulation of NK1R in colon devoid of mucosa and submucosa. Repeated WAS increased the contractile activities of longitudinal muscle and circular muscle strips induced by SP and this effect was reversed by a selective NK1R antagonist. The ICa,L of SMCs in the WAS rats were drastically increased compared to controls after addition of SP.

CONCLUSIONS

Increased serum SP level and up-regulated NK1R in colon may contribute to stress-induced colonic hypermotility. And L-type calcium channels play a potentially important role in the process of WAS-induced dysmotility.

The Grooved Rodent Incisor Recapitulates Rudimentary Teeth Characteristics of Ancestral Mammals

It is known from the paleontology studies of eutherian mammals that incisor numbers were reduced during evolution. The evolutionary lost incisors may remain as vestigial structures at embryonic stages. The recapitulation of the incisor patterns among mammalian species will potentially uncover the mechanisms underlying the phenotypic transition of incisors during evolution. Here, we showed that a minute tooth formed in the presumptive groove region of the gerbil upper incisor at the early developmental stages, during which multiple epithelial swellings and Shh transcription domains spatiotemporally appeared in the dental epithelium, suggests the existence of vestigial dental primordia. Interestingly, when we trimmed the surrounding mesenchyme from incisor tooth germs at or before the bud stage prior to ex vivo culture, the explants developed different incisor phenotypes ranging from triplicated incisors, duplicated incisors, to Lagomorpha-like incisors, corresponding to the incisor patterns in the eutherian mammals. These results imply that the phenotypic transition of incisors during evolution, as well as the achievement of ultimate incisors in adults, arose from differential integrations of primordia. However, when the incisor tooth germ was trimmed at the cap stage, a grooved incisor developed similar to the normal condition. Furthermore, the incisor tooth germ developed a small but smooth incisor after the additional removal of the minute tooth and a lateral rudiment. These results suggest that multiple dental primordia integrated before the cap stage, with the labial primordia contributing to the labial face of the functional incisor. The minute tooth that occupied the boundary of the 2 labial primordia might be implicated in the groove formation. This study sheds light on how rudiments incorporate into functional organs and aids the understanding of incisor evolution.