More Like this

1. Cardioprotective Effects Of Glycyrrhizin On Hyperglycemic Cardiac Tissues

   Munmun Chattopadhyay, Vikram Thakur ( July 2022 , Circulation)

   Introduction: Myocardial fibrosis and dysfunction is one of the major cardiac complications of long-term diabetes. Prolonged hyperglycemia is known to induce myocardial dysfunction often leading up to heart failure. Hypothesis: The objective of this study was to investigate the cardioprotective effect of glycyrrhizin (GLC) on myocardial damage in engineered in-vitro human cardiac tissues. Engineered 3D tissue chips present an ideal microenvironment via therapeutically relevant interfaces to study molecular- and cellular-level events and mimic human-specific disease states, and identify new therapeutic targets in vitro. Methods: AC16 human cardiomyocyte cells were used to 3D bioprint cardiac tissue chips based on prior publishedmore »work. In our study, the 3D bioprinted cardiac tissue chips (CTC) were cultured using normo- (5mM) and hyper-glycemic (25mM) conditions for up to 48 hrs. For the GLC treatment group, a subset of CTC cultured using hyperglycemic conditions were treated with 50 mM of GLC for 24 hours. Results: CTC cultured under hyperglycemic conditions demonstrated altered levels of connexin-43 (CX43) and Troponin-I implying cardiomyocyte injury. Exposure to hyperglycemia revealed changes in epigenetic markers: histone methylation marker (H3K9me)-1, Sirtuin-1, and Histone Deacetylase (HDAC)-2 as well as in inflammatory and stress related mediators such as heat shock protein (HSP)-60, receptor for advanced glycation end products (RAGE), toll like receptor (TLR)-4, high mobility group box (HMGB)-1 and CXC chemokine receptor (CXCR)-4. CTC exposed to 25mM glucose for 24 hours resulted in the downregulation of HSP60 and Sirtuin-1. Prolonged exposure to hyperglycemia led to decrease in the expression of CX43 and CXCR4; thereby adversely affecting cardiomyocyte function. Upregulated expression of DNA-binding nuclear protein HMGB1 along with changes in H3K9me1 indicated long-term hyperglycemia-induced damage to cardiomyocytes. GLC treated CTC exhibited a decrease in the expression of RAGE, TLR4 and also demonstrated altered expression of CX43, CXCR4, and troponin I. Conclusions: This study suggests that GLC possesses cardioprotective effects in human cardiomyocytes exposed to prolonged hyperglycemia.« less
2. Changes in Stress-Mediated Markers in a Human Cardiomyocyte Cell Line under Hyperglycemia

   https://doi.org/10.3390/ijms221910802  

   Thakur, Vikram ; Alcoreza, Narah ; Cazares, Jasmine ; Chattopadhyay, Munmun ( October 2021 , International Journal of Molecular Sciences)

   Diabetes is a major risk factor for cardiovascular diseases, especially cardiomyopathy, a condition in which the smooth muscles of the heart become thick and rigid, affecting the functioning of cardiomyocytes, the contractile cells of the heart. Uncontrolled elevated glucose levels over time can result in oxidative stress, which could lead to inflammation and altered epigenetic mechanisms. In the current study, we investigated whether hyperglycemia can modify cardiac function by directly affecting these changes in cardiomyocytes. To evaluate the adverse effect of high glucose, we measured the levels of gap junction protein, connexin 43, which is responsible for modulating cardiac electricmore »activities and Troponin I, a part of the troponin complex in the heart muscles, commonly used as cardiac markers of ischemic heart disease. AC16 human cardiomyocyte cells were used in this study. Under hyperglycemic conditions, these cells demonstrated altered levels of connexin 43 and Troponin-I after 24 h of exposure. We also examined hyperglycemia induced changes in epigenetic markers: H3K9me1, Sirtuin-1 (SIRT1), and histone deacetylase (HDAC)-2 as well as in inflammatory and stress-related mediators, such as heat shock protein (HSP)-60, receptor for advanced glycation end products (RAGE), toll-like receptor (TLR)-4, high mobility group box (HMGB)-1 and CXC chemokine receptor (CXCR)-4. Cardiomyocytes exposed to 25mM glucose resulted in the downregulation of HSP60 and SIRT1 after 48 h. We further examined that hyperglycemia mediated the decrease in the gap junction protein CX43, as well as CXC chemokine receptor CXCR4 which may affect the physiological functions of the cardiomyocytes when exposed to high glucose for 24 and 48 h. Upregulated expression of DNA-binding nuclear protein HMGB1, along with changes in histone methylation marker H3K9me1 have demonstrated hyperglycemia-induced damage to cardiomyocyte at 24 h of exposure. Our study established that 24 to 48 h of hyperglycemic exposure could stimulate stress-mediated inflammatory mediators in cardiomyocytes in vitro. These stress-related changes in hyperglycemia-induced cardiomyocytes may further initiate an increase in injury markers which eventually could alter the epigenetic processes. Therefore, epigenetic and inflammatory mechanisms in conjunction with alterations in a downstream signaling pathway could have a direct effect on the functionality of the cardiomyocytes exposed to high glucose during short and long-term exposures.« less
3. Multicellular 3D Neurovascular Unit Model for Assessing Hypoxia and Neuroinflammation Induced Blood-Brain Barrier Dysfunction

   https://doi.org/doi.org/10.1038/s41598-020-66487-8  

   Nzou, G ; Wicks, R. T. ; N. R., Mekky ; G. A., Seale ; S. A., Aya ; ... & Atala, A. J ( June 2020 , Scientific reports)

   The blood-brain barrier (BBB) is a dynamic component of the brain-vascular interface that maintains brain homeostasis and regulates solute permeability into brain tissue. The expression of tight junction proteins between adjacent endothelial cells and the presence of efflux proteins prevents entry of foreign substances into the brain parenchyma. BBB dysfunction, however, is evident in many neurological disorders including ischemic stroke, trauma, and chronic neurodegenerative diseases. Currently, major contributors to BBB dysfunction are not well understood. Here, we employed a multicellular 3D neurovascular unit organoid containing human brain microvascular endothelial cells, pericytes, astrocytes, microglia, oligodendrocytes and neurons to model the effectsmore »of hypoxia and neuroinflammation on BBB function. Organoids were cultured in hypoxic chamber with 0.1% O2 for 24 hours. Organoids cultured under this hypoxic condition showed increased permeability, pro-inflammatory cytokine production, and increased oxidative stress. The anti-inflammatory agents, secoisolariciresinol diglucoside and 2-arachidonoyl glycerol, demonstrated protection by reducing inflammatory cytokine levels in the organoids under hypoxic conditions. Through the assessment of a free radical scavenger and an anti-inflammatory endocannabinoid, we hereby report the utility of the model in drug development for drug candidates that may reduce the effects of ROS and inflammation under disease conditions. This 3D organoid model recapitulates characteristics of BBB dysfunction under hypoxic physiological conditions and when exposed to exogenous neuroinflammatory mediators and hence may have potential in disease modeling and therapeutic development.« less
4. Diabetic Conditions Confer Metabolic and Structural Modifications to Tissue-Engineered Skeletal Muscle

   https://doi.org/10.1089/ten.tea.2020.0138  

   Acosta, Francisca M. ; Jia, U-Ter Aonda ; Stojkova, Katerina ; Howland, Kennedy K. ; Guda, Teja ; Pacelli, Settimio ; Brey, Eric M. ; Rathbone, Christopher R. ( October 2020 , Tissue Engineering Part A)

   Abstract Skeletal muscle is a tissue that is directly involved in the progression and persistence of type 2 diabetes (T2D), a disease that is becoming increasingly common. Gaining better insight into the mechanisms that are affecting skeletal muscle dysfunction in the context of T2D has the potential to lead to novel treatments for a large number of patients. Through its ability to emulate skeletal muscle architecture while also incorporating aspects of disease, tissue-engineered skeletal muscle (TE-SkM) has the potential to provide a means for rapid high-throughput discovery of therapies to treat skeletal muscle dysfunction, to include that which occurs withmore »T2D. Muscle precursor cells isolated from lean or obese male Zucker diabetic fatty rats were used to generate TE-SkM constructs. Some constructs were treated with adipogenic induction media to accentuate the presence of adipocytes that is a characteristic feature of T2D skeletal muscle. The maturity (compaction and creatine kinase activity), mechanical integrity (Young's modulus), organization (myotube orientation), and metabolic capacity (insulin-stimulated glucose uptake) were all reduced by diabetes. Treating constructs with adipogenic induction media increased the quantity of lipid within the diabetic TE-SkM constructs, and caused changes in construct compaction, cell orientation, and insulin-stimulated glucose uptake in both lean and diabetic samples. Collectively, the findings herein suggest that the recapitulation of structural and metabolic aspects of T2D can be accomplished by engineering skeletal muscle in vitro. Impact Statement The tissue engineering of skeletal muscle to model disease and injury has great promise to provide a tool to develop and/or improve therapeutic approaches for improved health care. A tissue-engineered skeletal muscle model of one of the most common and debilitating diseases, type 2 diabetes, has been developed in vitro as evidenced by the structural and metabolic alterations that are consistent with the disease phenotype in vivo.« less
5. Methods for histological characterization of cryo-induced myocardial infarction in a rat model

   https://doi.org/10.1016/j.acthis.2020.151624  

   Alonzo, Matthew ; Delgado, Monica ; Cleetus, Carol M. ; AnilKumar, Shweta ; Thakur, Vikram ; Chattopadhyay, Munmun ; Joddar, Binata. ( January 2020 , Acta historica)

   Ligation of the left anterior descending (LAD) coronary artery has been commonly employed to induce myocardial infarction (MI) in animals; however, it is known to pose setbacks in the form of cardiac arrhythmias and unpredictable areas of necrotic damage. Cryo-infarction is an alternate method that has been adopted to create a reproducible model of a myocardial injury. In this study, Sprague-Dawley rats were subjected to thoracotomy followed by cryo-induced infarction of the heart, while the control-sham group was only subjected to thoracotomy following which the heart was collected from all animals. Tissue sections were stained with hematoxylin and eosin andmore »analyzed to determine cardiac muscle density, fiber length, and fiber curvature. Observations revealed reduced muscle density, cardiac fiber length, and distorted fibers in infarcted tissue sections. Gomori’s Trichrome staining was performed on tissue sections to study the effects of post MI on collagen, which showed enhanced intensity of collagen staining indicating fibrosis for the experimental models as compared to the sham models, an established consequence to myocardial injury. Immunohistochemical staining of the tissue sections with DAPI and connexin-43 (Cx-43) revealed that there was reduced DAPI staining and a less pronounced expression of Cx-43 in the experimental samples as compared to the sham samples. Results implied significant cell damage resulting from the cryo-infarction, subsequently disrupting and disaggregating the functional Cx-43 junction in cardiac myocytes, which is essential for normal and healthy cardiac physiology and function. This quantitative histological study of cryo-induced MI in a rat model can aid others attempting to optimize MI models in rats via cryo-injury, to study cardiac disease progression, and to aid in the construction of engineered cardiac tissues.« less