Tissue engineering: a historical review as seen through the US Patent Office

Issued US patents are utilised to describe the history of tissue engineering by implantation of dissociated cells in polymeric matrices. The history begins with patents issuing on applications filed in the late 1970s by Drs Yannas and Bell, who later founded Organogenesis. Next, the pivotal role of the technology developed by Drs Joseph Vacanti and Robert Langer is discussed, then the stromal cell matrices of Dr Gail Naughton, who founded Advance Tissue Sciences. The formation of businesses and product development is briefly correlated with the patents. Additional developments as described in the patents relate to methods for making polymeric matrices, methods for modifying polymers to interact with and modify the cellular interactions with the matrices, including cell attachment, differentiation and proliferation, and more recent advances specific to developments with stem cells and genetically engineered cells.     

Stem cells and small molecule screening: haploid embryonic stem cells as a new tool

Stem cells can both self-renew and differentiate into various cell types under certain conditions, which makes them a good model for development and disease studies. Recently, chemical approaches have been widely applied in stem cell biology by promoting stem cell self-renewal, proliferation, differentiation and somatic cell reprogramming using specific small molecules. Conversely, stem cells and their derivatives also provide an efficient and robust platform for small molecule and drug screening. Here, we review the current research and applications of small molecules that modulate stem cell self-renewal and differentiation and improve reprogramming, as well as the applications that use stem cells as a tool for small molecule screening. Moreover, we introduce the recent advance in haploid embryonic stem cells research. Haploid embryonic stem cells maintain haploidy and stable growth over extensive passages, possess the ability to differentiate into all three germ layers in vitro and in vivo, and contribute to the germlines of chimeras when injected into blastocysts. Androgenetic haploid stem cells can also be used in place of sperm to produce fertile progeny after intracytoplasmic injection into mature oocytes. Such characteristics demonstrate that haploid stem cells are a new approach for genetic studies at both the cellular and animal levels and that they are a valuable platform for future small molecule screening.     

急性脑梗死患者脑小血管病与主动脉粥样硬化的相关性研究

目的评价急性缺血性脑梗死患者脑小血管病(SVDs)与主动脉粥样硬化(AA)的相关性。方法123例急性脑梗死患者,入院后经食管超声心动图(TEE)和脑磁共振成像(MRI)对患者脑梗死进行评价。AA分为复杂主动脉斑块(CAP)和简单主动脉斑块(SAP)2个亚型。SVDs包括脑微出血(CMBs)、白质高信号(WMH)、血管周围间隙(PVSs)、无症状性腔隙性脑梗死(ALIs)和总SVD评分。结果检测到60例(48.8%)脑梗死患者存在AA,其中11.6%是CAP,37.2%是SAP。45例(36.4%)患者有1种或以上SVDs症状。在多变量分析中,AA患者中CMBs(OR:4.68)、重度WMHs(OR:3.13)、重度PVSs(OR:3.35)和ALIs(OR:4.24)出现的频率高于无AA患者。SVDs评分每增加1分均可使CAP[OR:1.94,95%CI(1.44,1.85)]和SAP[OR:1.54,95%CI(1.35,1.75)]发生概率增加。结论在本研究中,AA患者经常伴有大脑SVDs。而且急性脑梗死患者AA和大脑SVDs存在相关性。     

Cyclophosphamide and 4-hydroxycyclophosphamide pharmacokinetics in patients with glomerulonephritis secondary to lupus and small vessel vasculitis

AIMS

Cyclophosphamide, the precursor to the active 4-hydroxycyclophosphamide, is used in active glomerulonephritis despite limited pharmacokinetics data. The pharmacokinetics of cyclophosphamide and 4-hydroxycyclophosphamide were evaluated. The influence of laboratory and pharmacogenomic covariates on pharmacokinetics was evaluated as a secondary aim.

METHODS

Glomerulonephritis patients (n = 23) participated in a pharmacokinetic evaluation. Blood was serially collected and assayed for cyclophosphamide and 4-hydroxycyclophosphamide by LC/MS methods. Kidney function, serum albumin and polymorphisms in drug metabolism or transport genes were evaluated. Analyses included non-compartmental pharmacokinetics and parametric and non-parametric statistics.

RESULTS

The mean area under the plasma concentration–time curve (AUC(0,∞)) data were 110 100 ± 42 900 ng ml⁻¹ h and 5388 ± 2841 ng ml⁻¹ h for cyclophosphamide and 4-hydroxycyclophosphamide, respectively. The mean metabolic ratio was 0.06 ± 0.04. A statistically significant relationship was found between increased serum albumin and increased half-life (0.584, P = 0.007, 95% CI 0.176, 0.820) and a borderline relationship with AUC(0,∞) (0.402, P = 0.079, 95% CI –0.064, 0.724) for 4-hydroxycyclophosphamide. Covariate relationships that trended toward significance for cyclophosphamide included decreased serum albumin and increased elimination rate constant (–0.427, P = 0.061, 95% CI 0.738, 0.034), increased urinary protein excretion and increased AUC(0,∞) (–0.392, P = 0.064, 95% CI –0.699 to 0.037), decreased C_max (0.367, P = 0.085, 95% CI –0.067, 0.684) and decreased plasma clearance (–0.392, P = 0.064, 95% CI –0.699, 0.037). CYP2B6*9 variants vs. wildtype were found to have decreased elimination rate constant (P = 0.0005, 95% CI 0.033, 0.103), increased V_d (P = 0.0271, 95% CI −57.5, −4.2) and decreased C_max (P = 0.0176, 95% CI 0.696, 6179) for cyclophosphamide. ABCB1 C3435T variants had a borderline decrease in cyclophosphamide elimination rate constant (P = 0.0858; 95% CI –0.005, 0.102).

CONCLUSIONS

Pharmacokinetics of cyclophosphamide and 4-hydroxycyclophosphamide in patients with lupus nephritis and small vessel vasculitis are similar. Clinical and pharmacogenetic covariates alter disposition of cyclophosphamide and 4-hydroxycyclophosphamide. Clinical findings of worsened glomerulonephritis lead to increased exposure to cyclophosphamide vs. the active 4-hydroxycyclophosphamide, which could have relevance in terms of clinical efficacy. The CYP2B6*9 and ABCB1 C3435T polymorphisms alter the pharmacokinetics of cyclophosphamide and 4-hydroxycyclophosphamide in glomerulonephritis.     

维生素D水平与老年脑小血管病患者认知功能障碍的相关性研究

目的:分析老年脑小血管病（CSVD）患者的血清25-羟基维生素D［25（OH）D］水平与认知功能障碍之间的关系。方法:选择2019年12月至2020年12月于连云港市第二人民医院就诊的老年CSVD患者共97例,其中男56例、女41例,年龄65～85岁,依据蒙特利尔认知评估量表（MoCA）评分结果,分为CSVD认知正常组...     

Battling with environments: drug delivery to target tissues with particles and functional biomaterials

Recent years have seen a growing interest in drug-delivery technology as an enabling tool for complicated pharmacological activities. At the same time, this field has faced as many challenges as successes in translating novel ideas into clinical benefits. The Laboratory for Therapeutic Particles and Biomaterials Engineering at Purdue University (IN, USA) has striven to identify the current challenges in drug delivery and find solutions through the design of new drug-delivery systems. We develop new inhalable formulations for drug and gene delivery for cystic fibrosis patients, simple particle platforms for inhalable drug delivery, anion-resistant nonviral gene vectors, tumor-targeted nanoparticle systems, and hydrogel-based therapeutics. Through expanded collaborations with researchers in medicine and related disciplines, we strive to contribute to advancing the drug delivery field in a clinically relevant manner.     

Tissue engineering via local gene delivery: update and future prospects for enhancing the technology

This review describes the status of a local plasmid-based gene transfer technology known as the gene activated matrix (GAM). Studies over the past 6 years suggest that GAM may serve as a platform technology for local gene delivery in the wound bed of various tissues and organs. These studies demonstrated that plasmid encoding genes can be delivered to acutely injured tendon, ligament, bone, muscle, skin and nerve. Moreover, direct in vivo transfer of therapeutic plasmid encoding genes in bone, skin and nerve was associated with a significant regenerative response relative to sham controls. The review also describes new technology that should enhance the potential of local gene delivery in a manner consistent with the risk-benefit profile associated with tissue engineering applications.     

Development and engineering of lymphatic endothelial cells: clinical implications

Studies on the lymphatic endothelium have been hampered by the difficulty to identify lymphatic endothelial cells (LECs) and to distinguish them from blood vascular endothelial cells (BECs). The situation was greatly improved by the identification of molecules with high specificity for LECs. A great deal of progress in the field of lymphangiogenesis research has been due to the detection of lymphangiogenic growth factors and their receptors, and there is growing evidence that these molecules are also involved in tumor-induced lymphangiogenesis and lymphatic dissemination of tumor cells. There is a considerable spectrum of congenital and acquired lymphedema-lymphangiodysplasia syndromes ranging from primary aplasia, hypoplasia and hyperplasia to secondary (acquired) obstructive, obliterative and surgical hindrance of lymph drainage. Consequently, there are a number of clinical applications for therapeutics that either inhibit or induce lymphangiogenesis. Although natural lymphatic regeneration is mostly very efficient, engineering of LECs may be useful in cases of lymphatic aplasia or hypoplasia. To achieve these goals, studies on the embryonic development and differentiation of LECs will reveal the key regulatory factors that need to be targeted.     

人脐静脉血管内皮细胞构建组织工程心脏瓣膜及其生理功能

目的 探讨人脐静脉血管内皮细胞(HUVECs)构建组织工程心脏瓣膜(TEHV)及其生理功能.方法 以脱细胞猪主动脉瓣作支架;将扩增的HUVECs种植在瓣膜上,体外静态构建TEHV,观察内皮细胞的形态和生长状况.收集瓣膜培养液,检测瓣膜内皮细胞分泌组织型纤溶酶原激活物(t-PA)、组织型纤溶酶原激活物抑制物(PAI-1)、前列环素(PGI2)、一氧化氮(NO)、内皮素(ET-1)的功能.结果 猪主动脉瓣膜中的细胞成分能完全去除,脱细胞瓣叶的生物力学特性同新鲜瓣叶相比无明显变化以HUVECs做种子细胞,成功构建TEHV;瓣膜表面的内皮细胞生长状态良好,长成连续的细胞层.细胞能够分泌t-PA、PAI-1、PGI2、NO、ET-1等.结论 以脱细胞猪主动脉瓣膜为支架,种植HUVECs成功构建TEHV,其表面HUVECs具有正常内皮细胞的生理功能.     

Transtheoretical model constructs in smokers with and without medical illness: a second look at the medical effect

The present report describes an investigation of differences in transtheoretical model constructs between 275 smokers with any medical illness, smokers with chronic illness specifically, and smokers who are medically healthy. In contrast to a previous report by Kristeller et al., we did not find higher process scores among medically ill smokers, instead finding more relapses and higher temptation scores among the medically ill smokers. Chronically ill smokers in particular reported high temptation to smoke in negative affect and habit/craving situations. Moreover, greater number of chronic illnesses was associated with increasing temptation and pros of smoking. We conclude that while medical smokers may report more quit attempts, they may have more difficulty staying quit than their healthy counterparts. Helping medically ill smoking patients to cope more effectively with highly tempting situations, to decrease perceived benefits of smoking, and to increase their use of the processes of change may lead to greater cessation success.     

Adult mesenchymal stem cells in dental research: a new approach for tissue engineering

Many adult tissues contain a population of stem cells that have the ability to regenerate after trauma, disease or aging. Recently, there has been great interest in mesenchymal stem cells and their roles in maintaining the physiological structure of tissues. The studies on stem cells are thought to be very important and, in fact, it has been shown that this cell population can be expanded ex vivo to regenerate tissues not only of the mesenchymal lineage, such as intervertebral disc cartilage, bone and tooth-associated tissues, but also other types of tissues. Several studies have focused on the identification of odontogenic progenitors from oral tissues, and it has been shown that the mesenchymal stem cells obtained from periodontal ligament and dental pulp could have similar morphological and phenotypical features of the bone marrow mesenchymal cells. In fact a population of homogeneous human mesenchymal stem cells derived from periodontal ligament and dental pulp, and proliferating in culture with a well-spread morphology, can be recovered and characterized. Since these cells are considered as candidates for regenerative medicine, the knowledge of the cell differentiation mechanisms is imperative for the development of predictable techniques in implant dentistry, oral surgery and maxillo-facial reconstruction. Thus, future research efforts might be focused on the potential use of this cell population in tissue engineering. Further studies will be carried out to elucidate the molecular mechanisms involved in their maintenance and differentiation in vitro and in vivo.     

Socioeconomic status and substance use among young adults: a comparison across constructs and drugs

ABSTRACT. Objective: Little consensus exists regarding the relationship between socioeconomic status (SES) and substance use. This study examined the associations of three indicators of family SES during childhood-income, wealth, and parental education-with smoking, alcohol use, and marijuana use during young adulthood. Method: Data were obtained from the national Panel Study of Income Dynamics, a survey of U.S. families that incorporates data from parents and their children. In 2005 and 2007, the Panel Study of Income Dynamics was supplemented with two waves of Transition into Adulthood data drawn from a national sample of young adults, 18-23 years old. Data from the young adults (N = 1,203; 66.1% White; 51.5% female) on their current use of alcohol, cigarettes, and marijuana were used as outcome variables in logistic regressions. Socioeconomic background was calculated from parental reports of education, wealth, and income during the respondent's childhood (birth through age 17 years). Results: Smoking in young adulthood was associated with lower childhood family SES, although the association was explained by demographic and social role covariates. Alcohol use and marijuana use in young adulthood were associated with higher childhood family SES, even after controlling for covariates. Conclusions: Findings based on three indicators of family background SES-income, wealth, and parental education-converged in describing unique patterns for smoking and for alcohol and marijuana use among young adults, although functional relationships across SES measures varied. Young adults with the highest family background SES were most prone to alcohol and marijuana use. (J. Stud. Alcohol Drugs, 73, 772-782, 2012).     

酮洛芬及其异丙酯对HaCaT细胞构建的组织工程皮肤的渗透作用

目的体外构建适用于经皮给药研究的组织工程皮肤。方法以表皮角质形成细胞系HaCaT细胞及人真皮成纤维细胞为细胞来源，用I型牛胶原蛋白为真皮基质包埋成纤维细胞，其上接种HaCaT细胞，采用气-液界面方式培养，观察不同的培养介质对组织工程皮肤的影响，HE染色切片观察培养皮肤结构形态。以酮洛芬及其异丙酯为模型药物研究经皮渗透和代谢特性。结果HaCaT细胞经气-液界面培养可形成类表皮层，但不能形成完整的角质层。维生素C可明显促进细胞增殖，维生素D₃可促进细胞分化，雌二醇对此组织工程皮肤没有明显的影响。同皮肤细胞匀浆代谢相似，酮洛芬异丙酯被代谢成原药酮洛芬。结论HaCaT细胞在气-液界面培养条件下可形成多层分化不完全的表皮层，保留了一定的酶活性，可用于药物的经皮渗透和代谢等研究。     

Tissue distribution and pharmacodynamics: a complicated relationship

With few exceptions, drugs exert their effects not within the plasma compartment, but in the defined target tissues. The process of drug distribution to the active site constitutes the "link-bridge" of the pharmacokinetic/pharmacodynamic (PK/PD) relationship. In spite of the importance of drug distribution as a key factor in determining pharmacologic response, research on drug distribution has historically received much less attention than that of absorption, metabolism, and excretion. The negligence of research on drug distribution is due mainly to the inaccessibility of the target tissues for obvious ethical reasons. In addition, lack of reliable experimental tools to assess the distribution process is also a major contributing factor. Because of this negligence, drug distribution has been referred to as "the forgotten relative in clinical pharmacokinetics." Although recent advances in molecular biology have led to the identification of many drug transporters, many of the processes of drug distribution are still not fully understood. The primary aim of this article is to provide new insight into the mechanisms of drug distribution, with an attempt to describe the relationship between the drug distribution and pharmacologic response. In addition, the factors that affect the processes of drug distribution will also be reviewed. Also, validity of some key assumptions that are used to relate the processes of tissue distribution with pharmacologic activity will be discussed.     

Comparison of select cancer biomarkers in human circulating and bulk tumor cells using magnetic nanoparticles and a miniaturized micro-NMR system

Circulating tumor cells (CTC) harvested from peripheral blood have received significant interest as sources for serial sampling to gauge treatment efficacy. Nanotechnology and microfluidic based approaches are emerging to facilitate such analyses. While of considerable clinical importance, there is little information on how similar or different CTCs are from their shedding bulk tumors. In this clinical study, paired tumor fine needle aspirate and peripheral blood samples were obtained from cancer patients during image-guided biopsy. Using targeted magnetic nanoparticles and a point-of-care micro-NMR system, we compared selected biomarkers (EpCAM, EGFR, HER-2 and vimentin) in both CTC and fine needle biopsies of solid epithelial cancers. We show a weak correlation between each paired sample, suggesting that use of CTC as “liquid biopsies” and proxies to metastatic solid lesions could be misleading.From the Clinical EditorIn this clinical study, paired tumor fine needle aspirate and peripheral blood samples were obtained from patients with solid epithelial cancers during image-guided biopsy. Using targeted magnetic nanoparticles and a point-of-care micro-NMR system, the authors compared selected biomarkers in both circulating tumor cells (CTC) and fine needle biopsies, demonstrating a weak correlation between each paired sample, suggesting that use of CTC could be misleading in this context.     

脑小血管病血浆铁蛋白及纤维蛋白原与 D-二聚体的变化及其意义

目的：探讨血浆铁蛋白（SF）,纤维蛋白原（FIB）及D-二聚体水平和脑小血管病（SVD）的相关性。方法选取359例SVD患者,按照头颅MRI结果进一步分为腔隙性梗死组（ LI ）186例和白质疏松组（LA）173例。同时选择健康对照组146名。检测各组的SF（放免法）、FIB及D-二聚体（Clauss 法）水平。结果 SVD组SF、FIB及D-二聚体水平[（171．82±156．28）μg/L,（3．27±0．93）g/L,（1．10±1．06）mg/L]均明显高于健康对照组[（100．37±70．11）μg/L,（2．97±0．88） g/L,（0．83±0．55） mg/L]（均P＜0．05）。将SVD分为LI和LA进行比较发现,LA组各观测值[（185．22±108．55）μg/L,（3．32±0．86） g/L,（1．29±1．17）mg/L]均较LI组[（159．36±89．69）μg/L,（3．23±0．99）g/L,（1．03±0．80）mg/L]高,但差异均无统计学意义（均P＞0．05）。在校正相关因素后发现,高SF水平组（SF＞151．16μg/L）患SVD风险是低SF水平组（≤151．16μg/L）的3．44倍（OR＝3．444,95％CI为2．097～5．158,P＜0．001）。高D-二聚体水平组（＞1．02 mg/L）患SVD的风险较低D-二聚体组（≤1．02 mg/L）明显增加（OR＝1．767,95％CI为1．114～2．803,P＝0.016）。结论 SVD患者SF、FIB及D-二聚体水平高于健康人群,且SF及D-二聚体与SVD独立相关。