Extracellular matrix bioink boosts stemness and facilitates transplantation of intestinal organoids as a biosafe Matrigel alternative.

Organoids hold inestimable therapeutic potential in regenerative medicine and are increasingly serving as an in vitro research platform. Still, their expanding applications are critically restricted by the canonical culture matrix and system. Synthesis of a suitable bioink of bioactivity, biosecurity, tunable stiffness, and printability to replace conventional matrices and fabricate customized culture systems remains challenging. Here, we envisaged a novel bioink formulation based on decellularized extracellular matrix (dECM) from porcine small intestinal submucosa for organoids bioprinting, which provides intestinal stem cells (ISCs) with niche-specific ECM content and biomimetic microstructure. Intestinal organoids cultured in the fabricated bioink exhibited robust generation as well as a distinct differentiation pattern and transcriptomic signature. This bioink established a new co-culture system able to study interaction between epithelial homeostasis and submucosal cells and promote organoids maturation after transplantation into the mesentery of immune-deficient NODSCID-gamma (NSG) mice. In summary, the development of such photo-responsive bioink has the potential to replace tumor-derived Matrigel and facilitate the application of organoids in translational medicine and disease modeling.

Biological analysis of constituents in Spatholobi Caulis by UFLC-MS/MS: Enhanced quantification and application to permeability properties study in Caco-2 cell monolayer model.

Major chemical constituents in medicinal materials are often used as the marker compounds of traditional Chinese medicine (TCM) for treating various diseases. For spatholobi caulis (SPC), it contains a variety of flavones, phenolic acid esters, and lignans which exert many pharmacological effects. However, the absorption and permeability properties of these constituents of SPC are still unclear and require further investigation. Different types and major compounds of SPC were chosen as representative constituents to study their absorption and transepithelial transport characteristics in the human intestinal epithelium-like Caco-2 cell monolayer model. 35 constituents of SPC were evaluated by using ultra fast liquid chromatography combined with electrospray ionization triple quadrupole tandem mass spectrometry (UFLC-MS/MS) method, acetonitrile and water containing with 0.5 mM ammonium acetate were used as mobile phase, these analytes with good linear relationships (R2 was within 0.9967-0.9998), precision (CV values were less than 10.23 %, LLOQ was less than 13.69 %), accuracy (Mean of inter- and intra-day were within 85.02 %-111.61 % and 85.50-112.97 %, respectively) and stability (The mean was within 85.07 %-113.93 %), among which 16 analytes showed good permeability, 5 analytes were considered to be poorly permeable compounds, and the other 14 analytes were assigned for the moderately absorbed compounds in Caco-2 cell monolayer model. The further results showed that the absorption mechanism of 7 well absorbed compounds, 8-O-methylretusin (1), genistein (7), spasuberol B (16), naringenin (18), isoliquiritigenin (19), 4-hydroxy-3-methoxy cinnamic acid methyl ester (23) and (+)-epipinoresinol (31) in SPC was mainly passive diffusion, their bidirectional transport rate was correlated with the concentration and transport time. The chemical structures of these compounds could affect the permeability properties on the cell monolayer. This study demonstrated the utility of Caco-2 cell monolayer model for evaluating the absorption properties and initial mechanisms of compounds in SPC in vitro, and provided important basis for predicting oral bioavailability of SPC compounds.

Current knowledge on the multiform reconstitution of intestinal stem cell niche.

The development of "mini-guts" organoid originates from the identification of Lgr5+ intestinal stem cells (ISCs) and circumambient signalings within their specific niche at the crypt bottom. These in vitro self-renewing "mini-guts", also named enteroids or colonoids, undergo perpetual proliferation and regulated differentiation, which results in a high-performance, self-assembling and physiological organoid platform in diverse areas of intestinal research and therapy. The triumphant reconstitution of ISC niche in vitro also relies on Matrigel, a heterogeneous sarcoma extract. Despite the promising prospect of organoids research, their expanding applications are hampered by the canonical culture pattern, which reveals limitations such as inaccessible lumen, confine scale, batch to batch variation and low reproducibility. The tumor-origin of Matrigel also raises biosafety concerns in clinical treatment. However, the convergence of breakthroughs in cellular biology and bioengineering contribute to multiform reconstitution of the ISC niche. Herein, we review the recent advances in the microfabrication of intestinal organoids on hydrogel systems.

Nutritional Management of Patients With Enterocutaneous Fistulas: Practice and Progression.

The management of enterocutaneous fistulas (ECF) can be challenging because of massive fluid loss, which can lead to electrolyte imbalance, severe dehydration, malnutrition and sepsis. Nutritional support plays a key role in the management and successful closure of ECF. The principle of nutritional support for patients with ECF should be giving enteral nutrition (EN) priority, supplemented by parenteral nutrition if necessary. Although total parenteral nutrition (TPN) may be indicated, use of enteral feeding should be advocated as early as possible if patients are tolerant to it, which can protect gut mucosal barrier and prevent bacterial translocation. A variety of methods of enteral nutrition have been developed such as fistuloclysis and relay perfusion. ECF can also be occluded by special devices and then EN can be implemented, including fibrin glue application, Over-The-Scope Clip placement and three-dimensional (3D)-printed patient-personalized fistula stent implantation. However, those above should not be conducted in acute fistulas, because tissues are edematous and perforation could easily occur.

Current progress of source control in the management of intra-abdominal infections.

Intra-abdominal infection (IAI) is a deadly condition in which the outcome is associated with urgent diagnosis, assessment and management, including fluid resuscitation, antibiotic administration while obtaining further laboratory results, attaining precise measurements of hemodynamic status, and pursuing source control. This last item makes abdominal sepsis a unique treatment challenge. Delayed or inadequate source control is an independent predictor of poor outcomes and recognizing source control failure is often difficult or impossible. Further complicating issue in the debate is surrounding the timing, adequacy, and procedures of source control. This review evaluated and summarized the current approach and challenges in IAI management, which are the future research directions.

A reliable detachable balloon that prevents abdominal cavity contamination during transrectal natural orifice transluminal endoscopic surgery.

OBJECTIVE: To evaluate the efficacy and safety of a detachable endoluminal balloon in the prevention of abdominal cavity contamination during transrectal natural orifice transluminal endoscopic surgery (NOTES). METHODS: The efficacy and safety of a detachable endoluminal balloon to maintain disinfection in the distal colon of the pigs were evaluated. The bacterial loads and colonic cleanliness were monitored. Additionally, the device was applied to another nine pigs that underwent a cholecystotomy by transrectal NOTES. Necropsy and pathological examination were performed after 28-day follow-up. RESULTS: All animals exposed to the device and one of the seven pigs not exposed to the device scored three points on the bowel cleanliness scale (P < 0.001). After 30 min bacterial loads of the test (with balloon occlusion) and control (without balloon occlusion) groups showed a significant difference (0.8 × 103 CFU/mL vs 186.8 × 103 CFU/mL, P < 0.01). Cholecystotomy by transrectal NOTES with the device was successfully performed. The mean intraperitoneal procedure time was 102.9 ± 37.7 min. There were no procedure-related adverse events. During the follow-up, all animals presented normal behavior and appetite. No peritoneal infection or adhesion was detected at autopsy. Cholecystotomy and rectal incision were histologically healed and no histological abnormalities were detected in the colon related to balloon placement. CONCLUSIONS: The detachable balloon provides a reliable solution for preventing peritoneal contamination during transluminal operations. The technique may assist in future transrectal NOTES.

Simultaneous quantification of 33 active components in Notopterygii Rhizoma et Radix using ultra high performance liquid chromatography with tandem mass spectrometry.

A method of ultra high performance liquid chromatography with tandem mass spectrometry was developed for the simultaneous quantification of 33 active components including 26 coumarins and 7 phenolic acid esters in Notopterygii Rhizoma et Radix (NRR). Chromatographic separation was achieved on a Kinetex® C18 column (100 mm × 2.1 mm i.d.; 2.6 µm) with a gradient elution in 18 min. Electrospray ionization tandem mass spectrometric detection was conducted in the positive and negative ionization modes with multiple reaction monitoring. All of 33 analytes showed good linearity (R2 ≥ 0.9919) within the test range. The relative standard deviations of the precision, repeatability and stability were not exceeding 4.97%, and the recoveries were in the range of 85.37%-115.00%. The matrix effect on the response of target analyte was not obvious. The validated method was successfully applied to quantify the 33 components in ten batches of NRR samples. Quantitative results showed the coumarins and phenolic acid esters with large difference in level of content in the herb samples. Furthermore, hierarchical cluster analysis and principal component analysis were applied to classify and discriminate these samples. The variations of isoimperatorin, notopterol, bergamottin, nodakenin, phenethylferulate were suggested as important indicators of NRR quality. This work may serve for quality identification and comprehensive evaluation of NRR.

Impaired Coagulation Status in the Crohn's Disease Patients Complicated with Intestinal Fistula.

BACKGROUND: Intestinal fistula is one of the common complications of Crohn's disease (CD) that might require surgical treatment. The clinical characteristics and outcomes of CD with intestinal fistula are much different from CD alone. This study was to investigate whether the coagulation status of CD is changed by intestinal fistula. METHODS: Data were retrospectively analyzed for 190 patients with a definitive diagnosis of CD who were registered at the Jinling Hospital between January 2014 and September 2015. Baseline clinical characteristics and laboratory indices of initial admission and 7 days after intestinal fistula resections were collected. Student's t-test and the Wilcoxon rank-sum test were used to compare differences between the two groups. RESULTS: Compared with CD patients without intestinal fistula, prothrombin time (PT) in patients with intestinal fistula was significantly longer (12.13 ± 1.27 s vs. 13.18 ± 1.51 s, P < 0.001 in overall cohort; 11.56 ± 1.21 s vs. 12.61 ± 0.73 s, P = 0.001 in females; and 12.51 ± 1.17 s vs. 13.37 ± 1.66 s, P = 0.003 in males). Platelet (PLT) count was much lower in intestinal fistula group than in nonintestinal fistula group (262.53 ± 94.36 × 109/L vs. 310.36 ± 131.91 × 109/L, P = 0.009). Multivariate logistic regression showed that intestinal fistula was significantly associated with a prolonged PT (odds ratio [OR] = 1.900, P < 0.001), a reduced amount of PLT (OR = 0.996, P = 0.024), and an increased operation history (OR = 5.408, P < 0.001). Among 65 CD patients receiving intestinal fistula resections, PT was obviously shorter after operation than baseline (12.28 ± 1.16 s vs. 13.02 ± 1.64 s, P = 0.006). CONCLUSIONS: Intestinal fistula was significantly associated with impaired coagulation status in patients complicated with CD. Coagulation status could be improved after intestinal fistula resections.

3D-printed "fistula stent" designed for management of enterocutaneous fistula: An advanced strategy.

Enterocutaneous fistulas (ECFs) are great challenges during the open abdomen. The loss of digestive juice, water-electrolyte imbalance and malnutrition are intractable issues during management of ECF. Techniques such as "fistula patch" and vacuum-assisted closure therapy have been applied to prevent contamination of open abdominal wounds by intestinal fistula drainage. However, failures are encountered due to high-output fistula and anatomical complexity. Here, we report 3D-printed patient-personalized fistula stent for ECF treatment based on 3D reconstruction of the fistula image. Subsequent follow-up demonstrated that this stent was well-implanted and effective to reduce the volume of enteric fistula effluent.

Intestinal Absorption of Triterpenoids and Flavonoids from Glycyrrhizae radix et rhizoma in the Human Caco-2 Monolayer Cell Model.

Glycyrrhizae radix et rhizoma has been used as a traditional Chinese medicine for the treatment of various diseases. Triterpenoids and flavonoids from the plant have many beneficial effects and their chemical structures are modified in the gastrointestinal tract after oral administration. However, absorption of these triterpenoids and flavonoids still needs to be defined. Here, the uptake and transepithelial transport of the selected major triterpenoids, glycyrrhizin (1), glycyrrhetic acid-3-O-mono-ß-d-glucuronide (2), and glycyrrhetinic acid (3); and the selected major flavonoids, licochalcone A (4), licochalcone B (5), licochalcone C (6), echinatin (7), isoliquiritin apioside (8), liquiritigenin (9), liquiritin apioside (10) isolated from Glycyrrhizae radix et rhizoma, were investigated in the human intestinal epithelium-like Caco-2 cell monolayer model. Compounds 3, 5-7, and 9 were designated as well-absorbed compounds, 2 and 4 were designated as moderately absorbed ones, and 1, 8, and 10 were assigned for the poorly absorbed ones. The absorption mechanism of well and moderately absorbed compound was mainly passive diffusion to pass through the human intestinal Caco-2 cell monolayer. These findings provided useful information for predicting their oral bioavailability and the clinical application.

Anti-Inflammatory Phenolic Acid Esters from the Roots and Rhizomes of Notopterygium incisium and Their Permeability in the Human Caco-2 Monolayer Cell Model.

A new ferulic acid ester named 4-methyl-3-trans-hexenylferulate (1), together with eight known phenolic acid esters (2-9), was isolated from the methanolic extract of the roots and rhizomes of Notopterygium incisium. Their structures were elucidated by extensive spectroscopic techniques, including 2D NMR spectroscopy and mass spectrometry. 4-Methoxyphenethyl ferulate (8) NMR data is reported here for the first time. The uptake and transepithelial transport of the isolated compounds 1-9 were investigated in the human intestinal Caco-2 cell monolayer model. Compounds 2 and 6 were assigned for the well-absorbed compounds, compound 8 was assigned for the moderately absorbed compound, and compounds 1, 3, 4, 5, 7, and 9 were assigned for the poorly absorbed compounds. Moreover, all of the isolated compounds were assayed for the inhibitory effects against nitric oxide (NO) production in the lipopolysaccharide-activated RAW264.7 macrophages model and L-N6-(1-iminoethyl)-lysine (L-NIL) was used as a positive control. Compounds 1, 5, 8, and 9 exhibited potent inhibitory activity on NO production with the half maximal inhibitory concentration (IC50) values of 1.01, 4.63, 2.47, and 2.73 µM, respectively, which were more effective than L-NIL with IC50 values of 9.37 µM. These findings not only enriched the types of anti-inflammatory compounds in N. incisum but also provided some useful information for predicting their oral bioavailability and their suitability as drug leads or promising anti-inflammatory agents.

[FTIR Spectroscopic Characterization of Material Composition in Functional Leaf of Cotton under Stress of Potassium and Boron].

Potassium (K) and boron (B) are essential nutrient elements for plants, and the elements play an important role for plant growth, development and physiological metabolism. Cotton has a higher demand for K and B; K deficiency or B deficiency often occurs in cotton though. To reveal the component changes in functional leaf of cotton under K and B stress and investigate effects on material composition from K and B. A pot experiment was conducted at Huazhong Agricultural University. (1) the characteristic peaks at 1 546.86, 1 438.85, 1 153.39 and 1 024.17 cm(-1) disappeared due to B deficiency, and relative absorbance of other characteristic peaks was decreased compared with normal, which suggested that the structures of protein, fiber, soluble sugar and ribosome in cotton functional leaf changed and decreased in cotent when lack of K. (2) the relative absorbance of all characteristic peaks was increased in the B-deficient cotton leaves compared with normal, suggesting B deficiency leads to the accumulation in leaves of protein, and fiber, soluble sugar and other carbohydrates because of the hindered transportation. (3) lack of both potassium and boron, induced significant changes to both the locations and relative absorbance of characteristic peaks, and the content of protein, and soluble sugar and other carbohydrates increased, while the content of nucleic acids and polysaccharides dropped. K deficiency led to the structures of protein, fiber, soluble sugar and ribosome in cotton functional leaf changed and decreased in content; B deficiency gave rise to the accumulation in leaves of protein, and fiber, soluble sugar and other carbohydrates; the content of protein and soluble sugar and other carbohydrates increased, while the content of nucleic acids and polysaccharides dropped when K and B were all in short supply.

Anti-inflammatory coumarins with short- and long-chain hydrophobic groups from roots of Angelica dahurica cv. Hangbaizhi.

The (1)H NMR-guided fractionation of a cyclohexane soluble portion of the 75% ethanolic extract of the roots of Angelica dahurica cv. Hangbaizhi led to the isolation of two coumarins, namely, 5-(3"-hydroxy-3"-methylbutyl)-8-hydroxyfuranocoumarin, and isobyakangelicin hydrate-3"-ethyl ether, and ten coumarins with short- or long-chain hydrophobic groups, namely, andafocoumarins A-J. Their structures were elucidated by extensive spectroscopic analyses. The absolute configurations of the C-2" secondary alcohols in ten of these compounds were deduced via the circular dichroism data of the in situ formed [Rh2(OCOCF3)4] complex, and oxidation reactions were utilized to determine location of the double bonds in the lipid chain of andafocoumarins H and I, respectively. The long-chain hydrophobic group of andafocoumarin J was determined by the method of chemical degradation and GC-MS analysis. It was the first time that coumarins with short- or long-chain hydrophobic groups in this plant had been comprehensively investigated. All isolates were assayed for their inhibitory effect against nitric oxide (NO) production in a lipopolysaccharide (LPS)-activated RAW264.7 macrophage cell line, among which andafocoumarins A and B exhibited a potent inhibition on LPS-activated NO production with IC50 values of 19.7 and 13.9 µM, respectively, indicating their stronger inhibitory activity than l-N(6)-(1-iminoethyl)-lysine (IC50=23.7 µM), a selective inhibitor of inducible nitric oxide synthase.

[FTIR Study of Leaf of Different Cotton Genotypes under Potassium Substitution with Sodium.]

Potassium (K) deficiency affects cotton growth. The substitution effects of sodium (Na) and potassium research have been the focus of attention at home and abroad. The aim of this paper was to study the substitution effects of Na and K on material composition in leaf of two kinds of K-efficiency cotton genotypes (HG103 and LG122) using Fourier to transform infrared (FTIR) spectroscopy. The results showed that: (1) the increment of the relative absorbance of HG103 at peaks 2 960, 2 855 and 2 926 cm-1 were the same with LG122 with addition of Na in deficient K, while at peaks 1 078 and 1 103 cm-1, the increment of HG103 was higher than LG122, indicating that in deficient K, Na could promote the synthesis of carbohydrate, protein and esters, wherein the promoting effect on carbohydrate of HG103 was greater than LG122, while for protein and esters, there has no difference. However, the decrement of the relative absorbance at these five peaks of HG103 was higher than LG122 with addition of Na in adequate K, suggesting that in adequate K, the inhibitory effect of Na on carbohydrate, protein and esters of HG103 was less LG122. (2) the peaks at 1 734 and 1 437 cm-1 disappeared due to K dificiency, when added Na, these peaks did not appear, implying that the structure of amideⅠband and cellulose was broken when lack of K when added Na has no changes.

Absorbability, mechanism and structure-property relationship of three phenolic acids from the flowers of Trollius chinensis.

The absorption properties, mechanism of action, and structure-property relationship of three phenolic acids isolated from the flowers of Trollius chinensis Bunge, namely, proglobeflowery acid (PA), globeflowery acid (GA) and trolloside (TS), were investigated using the human Caco-2 cell monolayer model. The results showed that these three phenolic acids were transported across the Caco-2 cell monolayer in a time and concentration dependent manner at the Papp level of 10-5 cm/s, and their extent of absorption correlated with their polarity and molecular weight. In conclusion, all three of these compounds were easily absorbed through passive diffusion, which implied their high bioavailability and significant contribution to the effectiveness of T. chinensis.

Polymorphism of heat shock protein 70-2 and enterocutaneous fistula in Chinese population.

AIM: To investigate whether the heat shock protein 70-2 (HSP70-2) polymorphism is associated with enterocutaneous fistulas in a Chinese population. METHODS: This study included 131 patients with enterocutaneous/enteroatmospheric fistulas. Patients with inflammatory bowel disease or other autoimmune diseases were excluded from this study. All patients with enterocutaneous/enteroatmospheric fistulas were followed up for three months to observe disease recurrence. In addition, a total of 140 healthy controls were also recruited from the Jinling Hospital, matched according to the sex and age of the patient population. Genomic DNA was extracted from peripheral blood from each participant. The HSP70-2 restriction fragment length polymorphism related to the polymorphic PstI site at position 1267 was characterized by polymerase chain reaction (PCR). First PCR amplification was carried out, and then PCR products were digested with PstI restriction enzyme. The DNA lacking the polymorphic PstI site within HSP70-2 generates a product of 1117 bp in size (allele A), whereas the HSP70-2 PstI polymorphism produces two fragments of 936 bp and 181 bp in size (allele B). RESULTS: The frequency of the HSP70-2 PstI polymorphism did not differ between patients and controls; however, the A allele was more predominant in patients with enterocutaneous fistulas than in controls (60.7% vs 51.4%, P = 0.038, OR = 1.425, 95%CI: 1.019-1.994). Sixty-one patients were cured by a definitive operation, drainage operation, or percutaneous drainage while 52 patients were cured by nonsurgical treatment. There was no significant difference in the frequency of the HSP70-2 PstI polymorphism between the patients who had surgery compared to those who did not (P = 0.437, OR = 1.237, 95%CI: 0.723-2.117). Moreover, 11 patients refused any treatment for economic reasons or tumor burden, and 7 patients with enterocutaneous fistulas (5.8%) died during the follow-up period. However, there was no significant difference in the frequency of the HSP70-2 PstI polymorphism between the patients who survived compared to those who died (P = 0.403, OR = 0.604, 95%CI: 0.184-1.986). CONCLUSION: The A allele of the HSP70-2 PstI polymorphism was associated with enterocutaneous fistulas in this Chinese population.

Absorption properties and mechanism of trolline and veratric acid and their implication to an evaluation of the effective components of the flowers of Trollius chinensis.

AIM: To study the absorption properties and mechanism of two important components, trolline and veratric acid, from the flowers of Trollius chinensis, in order to better understand the contribution of these two compounds to the effectiveness of these flowers. METHOD: The human Caco-2 cell monolayer model was employed to study the transport of trolline and veratric acid from apical side (AP) to basal side (BL), and from BL to AP by determining the transport rates as the function of time and concentration and calculating apparent permeability coefficients (Papp). RESULTS: Trolline and veratric acid were transported across Caco-2 cell monolayer through different mechanisms in a concentration dependent manner. Trolline was transported at a Papp level of 10(-6) cm·s(-1) with a Papp AP→BL/Papp BL→AP ratio of more than 1.8 or less than 0.8, while veratric acid was transported at a Papp level of 10(-5)cm·s(-1) with a Papp AP→BL/Papp BL→AP ratio of close to 1.0. CONCLUSION: Trolline is moderately absorbed through an associative mechanism involving active and passive transport, and veratric acid is well-absorbed mainly through passive diffusion. These factors should be taken into account when chemically assessing the pharmacodynamic material basis of the flowers of T. chinensis.

Study of nitro-polycyclic aromatic hydrocarbons in particulate matter in Dongguan.

Total suspended and size-segregated atmospheric particles were collected in four seasons at three representative points in different functional areas of Dongguan City. The detailed size distributions of six nitro-PAHs [2-nitrofluorene (2-NF), 9-nitroanthracene, 2-nitrofluoranthene (2-NFL), 3-nitrofluoranthene, 1-nitropyrene, and 2-nitropyrene (2-NP)] were determined by high-performance liquid chromatography (HPLC) with UV detection using a binary elution gradient (methanol and water). We used a toxicity assessment based on potency equivalency factors (PEFs) to estimate the inhalation risk of the particulate matter. The results showed that, aside from 2-NF and 2-NFL, the content of the other four nitro-PAHs in the microparticles (<0.4 µm) were more than 20%, a percentage significantly higher than other fractions of particulate matter. The seasonal distribution of nitro-PAHs shows that their concentrations were higher in the winter, while the PAH concentrations were higher in the summer. The study found that secondary formation (2-NFL and 2-NP) had a positive correlation with NO x and NO2, but a negative correlation with O3. The benzo[a]pyrene equivalent (BaPeq) toxicity of particulate matter in Dongguan City ranged from 0.04 to 2.63 ng m(-3), and the carcinogenic index ranged from 0.04 × 10(-6) to 2.39 × 10(-6). These values do not represent a serious threat to human health.

Investigation on Flos Trollii: constituents and bioactivities.

Flos Trollii, the flowers of Trollius chinensis Bunge, has been widely used in Chinese and Mongolian medicine for its efficacy of heat-clearing and detoxification. This drug has both medicinal and edible applications, and has led to various pharmacognosy, natural product chemistry, and pharmacology studies. As a result, its chemical constituents and bioactivities have been well-characterized in recent years. Nevertheless, a couple of critical issues, such as the major effective components, are still unresolved. The present review summarizes research progress on this drug regarding the constituents and bioactivities based on investigations in these laboratories and the results reported in recent publications. In addition, the pending issues are discussed and constructive suggestions for further investigation are proposed.

Dulbecco's modified eagle's medium and minimum essential medium--which one is more preferred for establishment of Caco-2 cell monolayer model used in evaluation of drug absorption?

The Caco-2 cell monolayer model is widely used in drug absorption studies. Dulbecco's Modified Eagle's Medium (DMEM) and Minimum Essential Medium (MEM) have been used alternatively in the development of this model, although they are different in composition which may affect the differentiation and junction formation of the Caco-2 cell monolayer. Two Caco-2 cell monolayers cultured in both media were compared herein in order to underlay the standardization of this model. These two monolayers were comparatively evaluated regarding reliability and stability by morphology, transepithelial electrical resistance (TEER), alkaline phosphatase (AKPase) activity and transport experiments. Although the results showed that characteristic microvilli were present at the apical side of both monolayers, the dynamic change of TEER of the monolayer cultured in DMEM was more stable than that cultured in MEM, and AKPase activity of the former was stronger than that of the latter. Furthermore, the quantity of atenolol, a key indicator usually used for assessment of this model, across the monolayer cultured in MEM was significantly more than that cultured in DMEM. Therefore, the Caco-2 monolayer cultured in DMEM was more reliable and stable than that cultured in MEM, and thus the former was preferred for drug absorption investigation in vitro.