ABSTRACT
Background: Intestinal flora disorder plays an important role in the pathogenesis of chronic constipation. Either microbial agents or fecal microbiota transplantation has therapeutic effect on chronic constipation by regulating the intestinal flora. Aims: To study the characteristics of intestinal flora structure in elderly chronic constipation patients. Methods: Thirty elderly patients with chronic constipation from January 2019 to December 2019 at Nanjing Central Hospital were enrolled, and 30 elderly healthy subjects were served as controls. Stool was collected, and 16S rRNA high-throughput sequencing method was used to analyze the structure of intestinal flora. Results: Alpha diversity analysis showed that there were no significant differences in Ace, Chao, Shannon and Simpson indices between chronic constipation group and healthy control group. Twenty dominant genera accounting for more than 80% of all genera were identified in the two groups, Bacteroides was the most abundant genus. Beta diversity analysis showed that the species composition between the two groups was different, the characteristics of the two groups were not similar (R=0.098, P=0.001). Relative abundances of Prevotella, Faecalibacterium and Lachnospira were higher in the healthy control group, while Ruminococcus, Shigella, Parabacteroides and Alistipes were higher in chronic constipation group. Numbers of species with significantly different relative abundance in healthy control group and chronic constipation group were 25 and 2, respectively. Compared with healthy control group, the abundance of Alistipes, Oscillospira, Ruminococcus and Parabacteroides were higher in chronic constipation group (P< 0.05), while Megasphaera was lower (P< 0.05). Conclusions: There is no difference in the diversity of intestinal flora between elderly chronic constipation patients and elderly healthy controls, however, significant difference is detected in species composition. Therefore, targeting at modifying intestinal flora may be a promising therapeutic strategy for chronic constipation.
ABSTRACT
BACKGROUND: In the process of bone defect healing, the use of biological materials loaded with drugs for local defect intervention can accelerate the repair of the defect, which provides a new method for the local treatment of bone defects. OBJECTIVE: To introduce the local application of bone tissue engineering scaffolds loaded with bisphosphonates in bone defect repair and to summarize the effects of bone tissue engineering scaffolds as a drug delivery system on the bone defect healing. METHODS: The authors retrieved PubMed, Web of Science, Springerlink, Medline, WanFang and CNKI databases with "bisphosphonates, alendronate, zoledronate, bone defect, bone tissue engineering" as key words for relevant articles published from 2006 to 2018. Initially, 235 articles were retrieved, and finally 70 articles were selected for further analysis. RESULTS AND CONCLUSION: Bisphosphonate drug is an effective inhibitor of osteoclast dissolution. It can form a drug sustained release system on the local defect by being loaded to composite scaffolds, promote the formation of new bone and accelerate the healing of the defect. For the drug delivery system of bisphosphonates, suitable scaffold materials are crucial to the osteogenic effect of composite scaffolds in the defect area. At present, the carrier materials used for bisphosphonate-loaded composite scaffolds are mainly divided into organic materials and inorganic materials. Most polymeric organic materials can directly load bisphosphonates to form good drug sustained release in the local area and obviously exert their pro-osteogenic effects, while natural materials and most inorganic materials are often combined with other materials to form composite materials as carriers to optimize the carrier performance. Most studies have also confirmed that these composite materials loaded with bisphosphonates in the defect area exert osteogenic effect in the defect area.
ABSTRACT
BACKGROUND:With the development of three-dimensional (3D) printing technology, 3D printed porous titanium scaffolds as bone substitutes have become a research hotspot. OBJECTIVE:To introduce and discuss the effects of each parameter of 3D printed porous titanium scaffolds on bone ingrowth, and to sum out the optimal parameters for bone ingrowth. METHODS:The first author retrieved PubMed, Springerlink and Medline databases with“three-dimensional (3D) printing, scaffold, titanium, bone ingrowth”as keywords for relevant articles published from 2006 to 2016. 125 articles were retrieved initial y, and final y 42 eligible articles were included for analysis. RESULTS AND CONCLUSION:Pore size, porosity, pore structures and surface modifications of 3D printed porous titanium scaffolds al make effects on bone ingrowth or osteoblasts in scaffolds. Scaffolds with appropriate pore size and porosity can promote the vascularization and provide adequate nutrition and oxygen supplement, to ensure high cel viability. Regulations of cel performances, such as cel attachment, proliferation and differentiation, are also affected by pore structures and nano-scale surface modification. Herein, a detailed combination of the parameters, as mentioned above, can create a better porous scaffold for better bone ingrowth. Hence, the high-stability interface between bone and scaffolds may be obtained through the parameter adjustment.