Longitudinal Profiling of Fasting Plasma Metabolome in Response to Weight-Loss Interventions in Patients with Morbid Obesity.

It is well recognized that patients with severe obesity exhibit remarkable heterogeneity in response to different types of weight-loss interventions. Those who undergo Roux-en-Y gastric bypass (RYGB) usually exhibit more favorable glycemic outcomes than those who receive adjustable gastric banding (BAND) or intensive medical intervention (IMI). The molecular mechanisms behind these observations, however, remain largely unknown. To identify the plasma metabolites associated with differential glycemic outcomes induced by weight-loss intervention, we studied 75 patients with severe obesity (25 each in RYGB, BAND, or IMI). Using untargeted metabolomics, we repeatedly measured 364 metabolites in plasma samples at baseline and 1-year after intervention. Linear regression was used to examine whether baseline metabolites or changes in metabolites are associated with differential glycemic outcomes in response to different types of weight-loss intervention, adjusting for sex, baseline age, and BMI as well as weight loss. Network analyses were performed to identify differential metabolic pathways involved in the observed associations. After correction for multiple testing (q < 0.05), 33 (RYGB vs. IMI) and 28 (RYGB vs. BAND) baseline metabolites were associated with changes in fasting plasma glucose (FPG) or glycated hemoglobin (HbA1c). Longitudinal changes in 38 (RYGB vs. IMI) and 38 metabolites (RYGB vs. BAND) were significantly associated with changes in FPG or HbA1c. The identified metabolites are enriched in pathways involved in the biosynthesis of aminoacyl-tRNA and branched-chain amino acids. Weight-loss intervention evokes extensive changes in plasma metabolites, and the altered metabolome may underlie the differential glycemic outcomes in response to different types of weight-loss intervention, independent of weight loss itself.

Individualized driver amplitude in liver MR elastography: a linear regression study.

BACKGROUND: Current liver magnetic resonance elastography (MRE) scans often require adjustments to driver amplitude to produce acceptable images. This could lead to time wastage and the potential loss of an opportunity to capture a high-quality image. PURPOSE: To construct a linear regression model of individualized driver amplitude to improve liver MRE image quality. MATERIAL AND METHODS: Data from 95 liver MRE scans of 61 participants, including abdominal missing volume ratio (AMVR), breath-holding status, the distance from the passive driver on the skin surface to the liver edge (Dd-l), body mass index (BMI), and lateral deflection of the passive driver with respect to the human sagittal plane (Angle α), were continuously collected. The Spearman correlation analysis and lasso regression were conducted to screen the independent variables. Multiple linear regression equations were developed to determine the optimal amplitude prediction model. RESULTS: The optimal formula for linear regression models: driver amplitude (%) = -16.80 + 78.59 × AMVR - 11.12 × breath-holding (end of expiration = 1, end of inspiration = 0) + 3.16 × Dd-l + 1.94 × BMI + 0.34 × angle α, with the model passing the F test (F = 22.455, P <0.001) and R2 value of 0.558. CONCLUSION: The individualized amplitude prediction model based on AMVR, breath-holding status, Dd-l, BMI, and angle α is a valuable tool in liver MRE examination.

Plasma lipidomic markers of diet quality are associated with incident coronary heart disease in American Indian adults: the Strong Heart Family Study.

BACKGROUND: Identifying lipidomic markers of diet quality is needed to inform the development of biomarkers of diet, and to understand the mechanisms driving the diet- coronary heart disease (CHD) association. OBJECTIVES: This study aimed to identify lipidomic markers of diet quality and examine whether these lipids are associated with incident CHD. METHODS: Using liquid chromatography-mass spectrometry, we measured 1542 lipid species from 1694 American Indian adults (aged 18-75 years, 62% female) in the Strong Heart Family Study. Participants were followed up for development of CHD through 2020. Information on the past year diet was collected using the Block Food Frequency Questionnaire, and diet quality was assessed using the Alternative Healthy Eating Index-2010 (AHEI). Mixed-effects linear regression was used to identify individual lipids cross-sectionally associated with AHEI. In prospective analysis, Cox frailty model was used to estimate the hazard ratio (HR) of each AHEI-related lipid for incident CHD. All models were adjusted for age, sex, center, education, body mass index, smoking, alcohol drinking, level of physical activity, energy intake, diabetes, hypertension, and use of lipid-lowering drugs. Multiple testing was controlled at a false discovery rate of <0.05. RESULTS: Among 1542 lipid species measured, 71 lipid species (23 known), including acylcarnitine, cholesterol esters, glycerophospholipids, sphingomyelins and triacylglycerols, were associated with AHEI. Most of the identified lipids were associated with consumption of ω-3 (n-3) fatty acids. In total, 147 participants developed CHD during a mean follow-up of 17.8 years. Among the diet-related lipids, 10 lipids [5 known: cholesterol ester (CE)(22:5)B, phosphatidylcholine (PC)(p-14:0/22:1)/PC(o-14:0/22:1), PC(p-38:3)/PC(o-38:4)B, phosphatidylethanolamine (PE)(p-18:0/20:4)/PE(o-18:0/20:4), and sphingomyelin (d36:2)A] were associated with incident CHD. On average, each standard deviation increase in the baseline level of these 5 lipids was associated with 17%-23% increased risk of CHD (from HR: 1.17; 95% CI: 1, 1.36; to HR: 1.23; 95% CI: 1.05, 1.43). CONCLUSIONS: In this study, lipidomic markers of diet quality in American Indian adults are found. Some diet-related lipids are associated with risk of CHD beyond established risk factors.

Reproductive health factors in relation to risk of hypertension in postmenopausal women: Results from NHANES 2011-2014.

Few studies have systematically assessed the relationship between multiple reproductive factors and hypertension, and these limited studies paid more attention to age at menarche and menopause, abortion, or the number of live births, and yielded controversial results. This study aimed to explore the relationship between reproductive health factors and hypertension from 5 aspects: history of menstruation, pregnancy, delivery, gynecological surgery, and reproductive-related medication use. We analyzed data from the National Health and Nutrition Examination Survey 2011 to 2014. Data on reproductive factors were collected using a questionnaire survey. The associations between multiple reproductive factors and the risk of hypertension were assessed using multivariable logistic regression models. There were significant inverse associations between age at menopause (odds ratio [OR] = 0.984, 95% confidence interval [CI]: 0.971-0.998, P = .0234 per 1-year increase), age at first live birth (OR = 0.970, 95% CI: 0.944-0.998, P = .0346 per 1-year increase), age at last live birth (OR = 0.982, 95% CI: 0.964-0.999, P = .0488 per 1-year increase), and the risk of hypertension. In contrast, a positive association was found between the risk of hypertension and a history of gestational diabetes (OR = 1.693, 95% CI: 1.042-2.751, P = .0333), hysterectomy (OR = 1.398, 95% CI: 1.139-1.717, P = .0014), ovariectomy (OR = 1.374, 95% CI: 1.074-1.758, P = .0115), and birth control pill use (OR = 1.293, 95% CI: 1.035-1.616, P = .0236). Age at menopause but not menarche, is inversely associated with hypertension. A history of gestational diabetes, hysterectomy, ovariectomy, or birth control pills was associated with a higher risk of hypertension.

DNA methylation is differentially associated with glycemic outcomes by different types of weight-loss interventions: an epigenome-wide association study.

BACKGROUND: Alterations in DNA methylation (DNAm) have been reported to be a mechanism by which bariatric surgeries resulted in considerable metabolic improvements. Previous studies have mostly focused on change in DNAm following weight-loss interventions, yet whether DNAm prior to intervention can explain the variability in glycemic outcomes has not been investigated. Here, we aim to examine whether baseline DNAm is differentially associated with glycemic outcomes induced by different types of weight-loss interventions. METHODS: Participants were 75 adults with severe obesity who underwent non-surgical intensive medical intervention (IMI), adjustable gastric band (BAND) or Roux-en-Y gastric bypass (RYGB) (n = 25 each). Changes in fasting plasma glucose (FPG) and glycated hemoglobin (HbA1c) were measured at 1-year after intervention. DNAm was quantified by Illumina 450 K arrays in baseline peripheral blood DNA. Epigenome-wide association studies were performed to identify CpG probes that modify the effects of different weight-loss interventions on glycemic outcomes, i.e., changes in FPG and HbA1c, by including an interaction term between types of intervention and DNAm. Models were adjusted for weight loss and baseline clinical factors. RESULTS: Baseline DNAm levels at 3216 and 117 CpGs were differentially associated with changes in FPG and HbA1c, respectively, when comparing RYGB versus IMI. Of these, 79 CpGs were significant for both FPG and HbA1c. The identified genes are enriched in adaptive thermogenesis, temperature homeostasis and regulation of cell population proliferation. Additionally, DNAm at 6 CpGs was differentially associated with changes in HbA1c when comparing RYGB versus BAND. CONCLUSIONS: Baseline DNAm is differentially associated with glycemic outcomes in response to different types of weight-loss interventions, independent of weight loss and other clinical factors. Such findings provided initial evidence that baseline DNAm levels may serve as potential biomarkers predictive of differential glycemic outcomes in response to different types of weight-loss interventions.

Potential role of inflammation in relation to dietary sodium and ß-carotene with non-alcoholic fatty liver disease: a mediation analysis.

BACKGROUND: High sodium intake has been linked to the prevalence of non-alcoholic fatty liver disease (NAFLD), but underlying mechanism remains unclear. This study aims to explore the role of chronic inflammation in the association between sodium and NAFLD. We also observed whether ß-carotene, which had a strong anti-inflammatory effect, lowers the odds of NAFLD. METHODS: We performed mediation analyses to assess the mediating effects of C-reactive protein (CRP) and red cell distribution width (RDW) on the relationship between dietary sodium and NAFLD defined by the hepatic steatosis index (HSI) and the fatty liver index (FLI), respectively. RESULTS: A total of 6725 participants were included in this study. Compared with the high sodium-low carotene group, participants in the high sodium-high carotene group had 16% and 26% lower odds for HSI and FLI-defined NAFLD, respectively. There were positive indirect effects of dietary sodium intake on the HSI-defined NAFLD (indirect effect: 0.0057, 95% CI: 0.0021-0.0091, P < 0.0001), as well as the FLI defined NAFLD (indirect effect: 0.0081, 95% CI: 0.0024-0.0162, P < 0.0001) when C-reactive protein (CRP) was considered as a mediator. The mediating effects were somewhat attenuated after further adjusting for dietary ß-carotene intake. Similar results were found when RDW was considered as a mediator in the HSI-defined NAFLD analysis. CONCLUSIONS: Higher sodium intake increases the odds of NAFLD by upregulating inflammation. Dietary ß-carotene may attenuate this association by down regulating inflammation.

High-speed wavelength-swept femtosecond source from 1055 to 1300†nm using a GHz femtosecond fiber laser.

In this Letter, we demonstrate a high-speed broadband wavelength-swept femtosecond source (WFS) that leverages the soliton self-frequency shift (SSFS) and intensity-wavelength encoding technologies. The optical wavelength of the high-speed WFS can be continuously swept from 1055 nm to nearly 1300 nm at a sweeping rate of 100 kHz. This WFS is especially seeded by a femtosecond mode-locked all-fiber laser at 1055 nm that has a fundamental repetition rate of ∼1.0 GHz, a maximum output power of 7 W, and a compressed pulse width of 220 fs. It is anticipated that this high-speed broadband WFS can be a promising source for applications that require fast wavelength scanning and high-speed data processing.

Associations of Serum and Red Blood Cell Folate With All-Cause and Cardiovascular Mortality Among Hypertensive Patients With Elevated Homocysteine.

Objectives: This study aims to explore the associations between serum and red blood cell (RBC) folate as indicators of short- and long-term folate status, respectively, and all-cause as well as CVD mortality among hypertensive patients with elevated homocysteine. Methods: A prospective cohort study of the National Health and Nutrition Examination Survey (1999-2006) and 2015 Linked Mortality File was performed. All-cause and CVD mortality risk estimated using Cox proportional hazards models with adjusting for multiple potential covariates. Results: A total of 1,753 hypertensive patients with elevated homocysteine [mean (SD) age, 68.5 (13.1)] were included in the analysis. During a median follow-up of 10.0 years, a total of 899 all-cause and 257 CVD deaths occurred. Compared the highest with the lowest quartile of RBC folate, the multivariable adjusted hazard ratios and 95% confidence intervals for all-cause and CVD death were 1.13 (0.92-1.39) and 1.47 (1.01-2.16) respectively. There was a significant and positive trend between RBC folate and the risk of CVD death (p for trend = 0.0196). No significant association was found between serum folate and mortality risk among the study sample. Conclusions: High level of RBC folate is associated with an increased risk of cardiovascular mortality among hypertensive patients with elevated homocysteine while serum folate has no such effects.

Racial, Ethnic, and Geographic Disparities in Cardiovascular Health Among Women of Childbearing Age in the United States.

Background In the United States, large disparities in cardiovascular health (CVH) exist in the general population, but little is known about the CVH status and its disparities among women of childbearing age (ie, 18-49 years). Methods and Results In this cross-sectional study, we examined racial, ethnic, and geographic disparities in CVH among all women of childbearing age in the United States, using the 2011 to 2019 Behavioral Risk Factor Surveillance System. Life's Simple 7 (ie, blood pressure, glucose, total cholesterol, smoking, body mass index, physical activity, and diet) was used to examine CVH. Women with 7 ideal CVH metrics were determined to have ideal CVH. Among the 269 564 women of childbearing age, 13 800 (4.84%) had ideal CVH. After adjusting for potential confounders, non-Hispanic Black women were less likely to have ideal CVH (odds ratio, 0.54; 95% CI, 0.46-0.63) compared with non-Hispanic White women, and with significantly lower odds of having ideal metrics of blood pressure, blood glucose, body mass index, and physical activity. No significant difference in CVH was found between non-Hispanic White and Hispanic women. Large geographic disparities with temporal variations were observed, with the age- and race-adjusted ideal CVH prevalence ranging from 4.05% in the District of Columbia (2011) to 5.55% in Maine and Montana (2019). States with low ideal CVH prevalence and average CVH score were mostly clustered in the southern United States. Conclusions Large racial, ethnic, and geographic disparities in CVH exist among women of childbearing age. More efforts are warranted to understand and address these disparities.

High-power femtosecond all-fiber laser system at 1.5 µm with a fundamental repetition rate of 4.9 GHz.

In this Letter, we demonstrate a high-power femtosecond all-fiber laser system at 1.5 µm that operates at a fundamental repetition rate of up to 4.9 GHz. This high repetition rate laser system delivers an average power of 10 W and a pulsewidth of 63 fs in an all-fiber configuration-the best overall performance at 1.5 µm, so far, in terms of the all-fiber design, high average power, short pulsewidth, and high fundamental repetition rate. Integrated from 10 Hz to 10 MHz, this high-power femtosecond all-fiber laser system exhibits a relative intensity noise of only 0.4%. It is anticipated that this femtosecond laser system is promising for various applications, such as high-speed micromachining, wide-field multiphoton bioimaging, and nonlinear optics.

An external exposome-wide association study of COVID-19 mortality in the United States.

The risk factors for severe COVID-19 beyond older age and certain underlying health conditions are largely unknown. Recent studies suggested that long-term environmental exposures may be important determinants of severe COVID-19. However, very few environmental factors have been studied, often separately, without considering the totality of the external environment (i.e., the external exposome). We conducted an external exposome-wide association study (ExWAS) using the nationwide county-level COVID-19 mortality data in the contiguous US. A total of 337 variables characterizing the external exposome from 8 data sources were integrated, harmonized, and spatiotemporally linked to each county. A two-phase procedure was used: (1) in Phase 1, a random 50:50 split divided the data into a discovery set and a replication set, and associations between COVID-19 mortality and individual factors were examined using mixed-effect negative binomial regression models, with multiple comparisons addressed, and (2) in Phase 2, a multivariable regression model including all variables that are significant from both the discovery and replication sets in Phase 1 was fitted. A total of 13 and 22 variables were significant in the discovery and replication sets in Phase 1, respectively. All the 4 variables that were significant in both sets in Phase 1 remained statistically significant in Phase 2, including two air toxicants (i.e., nitrogen dioxide or NO2, and benzidine), one vacant land measure, and one food environment measure. This is the first external exposome study of COVID-19 mortality. It confirmed some of the previously reported environmental factors associated with COVID-19 mortality, but also generated unexpected predictors that may warrant more focused evaluation.

Real-time multispeckle spectral-temporal measurement unveils the complexity of spatiotemporal solitons.

The dynamics of three-dimensional (3D) dissipative solitons originated from spatiotemporal interactions share many common characteristics with other multi-dimensional phenomena. Unveiling the dynamics of 3D solitons thus permits new routes for tackling multidisciplinary nonlinear problems and exploiting their instabilities. However, this remains an open challenge, as they are multi-dimensional, stochastic and non-repeatable. Here, we report the real-time speckle-resolved spectral-temporal dynamics of a 3D soliton laser using a single-shot multispeckle spectral-temporal technology that leverages optical time division multiplexing and photonic time stretch. This technology enables the simultaneous observation on multiple speckle grains to provide long-lasting evolutionary dynamics on the planes of cavity time (t) - roundtrip and spectrum (λ) - roundtrip. Various non-repeatable speckly-diverse spectral-temporal dynamics are discovered in both the early and established stages of the 3D soliton formation.

Salt added to food and body mass index: A bidirectional Mendelian randomisation study.

AIM: This study aimed to determine the causal association between salt added to food and body mass index (BMI) by integrating a summary-level genome-wide association study (GWAS) data. METHODS: We performed two-sample Mendelian randomisation (MR) analyses using summary statistics of GWAS. Inverse-variance weighted (IVW), maximum likelihood estimation, and random effect model were used to analyse the effect of salt added to food on BMI. A bidirectional MR analysis with BMI as the exposure and salt added to food as the outcome was also performed. RESULTS: The single nucleotide polymorphisms (SNPs) were selected from the UK Biobank (n = 462 630) and a meta-analysis of 322 154 European-descent individuals. The IVW method estimate indicated that salt added to food was positively associated with BMI (ß = 0.1416, SE = 0.0576, P = .0139). Results from maximum likelihood estimation (ß = 0.1476, SE = 0.0363, P < .0001) and the random effect model (ß = 0.1411, SE = 0.0572, P = .0137) were consistent with the IVW. Bidirectional MR analysis suggested that BMI did not causally affect salt added to food. CONCLUSION: Our results provided qualitative evidence supporting a causal relationship between salt intake and BMI.

Red blood cell folate and severe abdominal aortic calcification: Results from the NHANES 2013-2014.

BACKGROUND AND AIMS: Abdominal aortic calcification (AAC) has been introduced as a good predictor of cardiovascular disease (CVD) events, but no previous study has investigated the relationship between folate levels and AAC. The present study aims to explore the relationship between red blood cell (RBC) folate, a better indicator reflecting long-term folate intake, and severe AAC in the United States (US) middle-aged and elderly population. METHODS AND RESULTS: Cross-sectional data were derived from the National Health and Nutrition Examination Survey (NHANES) 2013-2014 of 2818 men and women aged 40 years or older. Multivariable logistic regression models were used to determine odds ratios (ORs) and 95% confidence intervals (CIs) for severe AAC of each RBC folate quintile category. The restricted cubic spline model was used for the dose-response analysis. A U-shaped dose-response relation between RBC folate and the odds of severe AAC was found after adjustment for multiple potential confounding factors, p for nonlinear = 0.0032. With the third quintile category of RBC folate as the reference, multivariable-adjusted ORs and 95% CIs of the lowest, second, fourth, and the highest quintile categories were 2.34 (1.37-4.00), 1.24 (0.70-2.19), 1.58 (0.92-2.70), and 2.26 (1.35-3.76), respectively. CONCLUSIONS: Individuals with either low or high levels of RBC folate were at increased risks of severe AAC in a representative sample of US adults. While folate deficiency is widely recognized as harmful, these results highlight the need to investigate the potential adverse health outcomes of high folate level.

Relationship between dietary choline intake and diabetes mellitus in the National Health and Nutrition Examination Survey 2007-2010.

BACKGROUND: Little is known about the relationship between dietary intake of choline, which is a major dietary precursor for gut microbiome-derived trimethylamine N-oxide (TMAO), and diabetes mellitus (DM) in the general population. The present study aims to explore the relationship between dietary choline intake and DM in the US adult population. METHODS: Cross-sectional data were derived from the National Health and Nutrition Examination Survey (NHANES) 2007-2010 of 8621 individuals aged 20 years or older. Multivariable logistic regression models were used to determine odds ratios (ORs) and 95% confidence intervals (CIs) for DM of each quartile category of energy-adjusted choline intakes. The restricted cubic spline model was used for the dose-response analysis. The receiver operating characteristic (ROC) curve was used to determine the optimal cutoff value of choline intake for predicting DM. RESULTS: A linear dose-response relationship between dietary choline intake and the odds of DM was found after adjustment for multiple potential confounding factors. With the lowest quartile category of choline as the reference, the multivariable-adjusted ORs and 95% CIs of the second, third, and highest quartile categories were 1.23 (0.99-1.53), 1.27 (1.02-1.58), and 1.49 (1.20-1.85), respectively, P for trend =0.0004. The ROC analysis identified energy-adjusted choline of 331.7 mg/8.37-MJ per day as the optimal cutoff value for predicting DM, with 52.5% sensitivity and 60.7% specificity. CONCLUSION: This study supports a positive and linear relationship between dietary choline intake and DM in the US adult population.

Associations between the chemical composition of PM2.5 and gestational diabetes mellitus.

BACKGROUND: Fine particulate matter (PM2.5) is a complex mixture of fine particulates with large spatiotemporal heterogeneities in chemical compositions. While PM2.5 has been associated with gestational diabetes mellitus (GDM), little is known about the relationship between specific chemical components of PM2.5 and GDM. We examined the associations between GDM and pregnancy exposures to PM2.5 and its compositions, including sulfate (SO42-), ammonium (NH4+), nitrate (NO3-), organic matter (OM), black carbon (BC), mineral dust (DUST), and sea-salt (SS), and to identify critical windows of exposure. METHODS: We used data from the 2005-2015 Florida Vital Statistics Birth Records. A well-validated geoscience-derived model was used to estimate women's pregnancy exposures to PM2.5 and its compositions. Distributed lag models were used to examine the associations and to identify the critical windows of exposure. RESULTS: A total of 2,078,669 women were included. In single-pollutant models, after controlling for potential confounders, positive associations between PM2.5 and GDM were observed during the second trimester of pregnancy. We found positive associations between SO42-, NH4+, NO3-, OM and BC, with largest effect sizes observed in the 21-24 weeks of pregnancy. Negative associations were observed for DUST and SS. Consistent results for NH4+, OM, DUST and SS were observed in the multi-pollutant models. CONCLUSIONS: Exposures to PM2.5 and its compositions (mainly NH4+, OM) during the second trimester are positively associated with GDM, especially for exposures during the 21-24 weeks of pregnancy. Further studies are needed to confirm the findings and examine the underlying mechanisms.

>100 W GHz femtosecond burst mode all-fiber laser system at 1.0 µm.

In this work, we report a >100 W femtosecond (fs) burst mode all-fiber laser system at 1.0 µm that operates at an intra-burst repetition rate of up to 1.2 GHz. This fiber laser system provides the highest output power that has been reported so far for GHz fs fiber lasers, to the best of our knowledge. In addition to the superior output power, this fiber laser system also shows a promising overall figure of merit, specifically in terms of pulse width (473 fs), long-term reliability (<0.67% power fluctuation) and system compactness (all-fiber configuration). We anticipate that this all-fiber laser system can be a promising ultrafast laser source for these applications requiring fs pulses with both high average power and high repetition rate, such as micromachining, bioimaging and frequency metrology.

Association Between Serum Cotinine and Severe Abdominal Aortic Calcification in US Adults.

This study aims to explore the association between serum cotinine and severe abdominal aortic calcification (AAC) in the US adults. We examined 2840 participants with a weighted mean age of 57.4 years from the National Health and Nutrition Examination Survey 2013-2014. Serum cotinine was analyzed as the main exposure both continuously and categorically (tertiles). Abdominal aortic calcification detected with dual-energy X-ray absorptiometry was quantified using the Kauppila score system. Severe AAC was detected in 252 (8.9%) participants. The multivariable-adjusted odds ratios and 95% confidence intervals (CIs) of the middle and top cotinine categories were 1.14 (0.79-1.64) and 1.80 (1.21-2.68), respectively, P for trend = .004. Per unit increase in log-transformed serum cotinine was associated with 10% (95% CI: 6%-15%) higher odds of severe AAC when serum cotinine was analyzed as a continuous variable. The association was consistent across sex and ethnic groups. In conclusion, elevated serum cotinine level was associated with higher odds for severe AAC in a representative sample of US adults.

Biodegradable cell-laden starch foams for the rapid fabrication of 3D tissue constructs and the application in neural tissue engineering.

Cells encapsulation by biomaterials has been widely studied as a strategy of building tissue construct in tissue engineering. Conventional encapsulation of cells using hydrogels often needs the polymerization process or relatively complex molding process. In this study, we developed a facile strategy for the in situ fabrication of biodegradable cell-laden starch foams. By utilizing the unique gelatinization property of starch, cell-laden starch foams with tunable architecture were rapidly prepared in a green and biological-friendly process. The bubble size and stiffness of starch foams could be tuned by controlling the content of premixed starch in the cell culture medium. Cells were encapsulated in situ during the foaming process, and the resultant starch foams could be used as building blocks to fabricate three-dimensional tissue construct. The potential application of the cell-laden starch foams in neural tissue engineering was also validated. RSC96 Schwann cells were encapsulated in the starch foams and revealed good viability. Due to the serum-induced degradation of the starch, RSC96 Schwann cells could be released from the starch foams in a controlled manner while remaining high viability. Dorsal root ganglion (DRG) neurons co-cultured with the cell-laden starch foams extended significantly longer neurites compared with neurons cultured in minimum Eagle's medium (664.88 ± 190.39 µm vs. 311.19 ± 105.25 µm). DRG neurons retained high viability even after encapsulation in the starch foams for 3 days. This facile strategy of rapidly fabricating cell-laden starch foams can be further extended to construct centimeter-scale micro-tissue for tissue engineering applications. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 108B:104-116, 2020.