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Wang B, Iglesias-Ledon L, Bishop M, Chadha A, Rudolph SE, Longo BN, Cairns DM, Chen Y, Kaplan DL. Impact of Micro- and Nano-Plastics on Human Intestinal Organoid-Derived Epithelium. Curr Protoc 2024; 4:e1027. [PMID: 38588063 DOI: 10.1002/cpz1.1027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/10/2024]
Abstract
The development of patient-derived intestinal organoids represents an invaluable model for simulating the native human intestinal epithelium. These stem cell-rich cultures outperform commonly used cell lines like Caco-2 and HT29-MTX in reflecting the cellular diversity of the native intestinal epithelium after differentiation. In our recent study examining the effects of polystyrene (PS), microplastics (MPs), and nanoplastics (NPs), widespread pollutants in our environment and food chain, on the human intestinal epithelium, these organoids have been instrumental in elucidating the absorption mechanisms and potential biological impacts of plastic particles. Building on previously established protocols in human intestinal organoid culture, we herein detail a streamlined protocol for the cultivation, differentiation, and generation of organoid-derived monolayers. This protocol is tailored to generate monolayers incorporating microfold cells (M cells), key for intestinal particle uptake but often absent in current in vitro models. We provide validated protocols for the characterization of MPs/NPs via scanning electron microscopy (SEM) for detailed imaging and their introduction to intestinal epithelial monolayer cells via confocal immunostaining. Additionally, protocols to test the impacts of MP/NP exposure on the functions of the intestinal barrier using transendothelial electrical resistance (TEER) measurements and assessing inflammatory responses using cytokine profiling are detailed. Overall, our protocols enable the generation of human intestinal organoid monolayers, complete with the option of including or excluding M cells, offering crucial techniques for observing particle uptake and identifying inflammatory responses in intestinal epithelial cells to advance our knowledge of the potential effects of plastic pollution on human gut health. These approaches are also amendable to the study of other gut-related chemical and biological exposures and physiological responses due to the robust nature of the systems. © 2024 Wiley Periodicals LLC. Basic Protocol 1: Human intestinal organoid culture and generation of monolayers with and without M cells Support Protocol 1: Culture of L-WRN and production of WRN-conditioned medium Support Protocol 2: Neuronal cell culture and integration into intestinal epithelium Support Protocol 3: Immune cell culture and integration into intestinal epithelium Basic Protocol 2: Scanning electron microscopy: sample preparation and imaging Basic Protocol 3: Immunostaining and confocal imaging of MP/NP uptake in organoid-derived monolayers Basic Protocol 4: Assessment of intestinal barrier function via TEER measurements Basic Protocol 5: Cytokine profiling using ELISA post-MP/NP exposure.
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Affiliation(s)
- Brooke Wang
- Department of Biomedical Engineering, Tufts University, Medford, Massachusetts
| | | | - Matthew Bishop
- Department of Biomedical Engineering, Tufts University, Medford, Massachusetts
| | - Anushka Chadha
- Department of Biomedical Engineering, Tufts University, Medford, Massachusetts
| | - Sara E Rudolph
- Department of Biomedical Engineering, Tufts University, Medford, Massachusetts
| | - Brooke N Longo
- Department of Biomedical Engineering, Tufts University, Medford, Massachusetts
| | - Dana M Cairns
- Department of Biomedical Engineering, Tufts University, Medford, Massachusetts
| | - Ying Chen
- Department of Biomedical Engineering, Tufts University, Medford, Massachusetts
| | - David L Kaplan
- Department of Biomedical Engineering, Tufts University, Medford, Massachusetts
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Chen Y, Williams AM, Gordon EB, Rudolph SE, Longo BN, Li G, Kaplan DL. Biological effects of polystyrene micro- and nano-plastics on human intestinal organoid-derived epithelial tissue models without and with M cells. Nanomedicine 2023; 50:102680. [PMID: 37105344 DOI: 10.1016/j.nano.2023.102680] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 03/15/2023] [Accepted: 04/07/2023] [Indexed: 04/29/2023]
Abstract
Micro- and nano-plastics (MPs and NPs) released from plastics in the environment can enter the food chain and target the human intestine. However, knowledge about the effects of these particles on the human intestine is still limited due to the lack of relevant human intestinal models to validate data obtained from animal studies or tissue models employing cancer cells. In this study, human intestinal organoids were used to develop epithelia to mimic the cell complexity and functions of native tissue. Microfold cells (M cells) were induced to distinguish their role when exposure to MPs and NPs. During the exposure, the M cells acted as sensors, capturers and transporters of larger sized particles. The epithelial cells internalized the particles in a size-, concentration-, and time-dependent manner. Importantly, high concentrations of particles significantly triggered the secretion of a panel of inflammatory cytokines linked to human inflammatory bowel disease (IBD).
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Affiliation(s)
- Ying Chen
- Department of Biomedical Engineering, Tufts University, 4 Colby St, Medford, MA 02155, USA.
| | - Ashleigh M Williams
- Department of Biomedical Engineering, Tufts University, 4 Colby St, Medford, MA 02155, USA
| | - Edward B Gordon
- Department of Biomedical Engineering, Tufts University, 4 Colby St, Medford, MA 02155, USA
| | - Sara E Rudolph
- Department of Biomedical Engineering, Tufts University, 4 Colby St, Medford, MA 02155, USA
| | - Brooke N Longo
- Department of Biomedical Engineering, Tufts University, 4 Colby St, Medford, MA 02155, USA
| | - Gang Li
- Department of Biomedical Engineering, Tufts University, 4 Colby St, Medford, MA 02155, USA; National Engineering Laboratory for Modern Silk, College of Textile and Clothing Engineering, Soochow University, Suzhou 215123, China
| | - David L Kaplan
- Department of Biomedical Engineering, Tufts University, 4 Colby St, Medford, MA 02155, USA.
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Rudolph SE, Longo BN, Tse MW, Houchin MR, Shokoufandeh MM, Chen Y, Kaplan DL. Crypt-Villus Scaffold Architecture for Bioengineering Functional Human Intestinal Epithelium. ACS Biomater Sci Eng 2022; 8:4942-4955. [PMID: 36191009 PMCID: PMC10379436 DOI: 10.1021/acsbiomaterials.2c00851] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Crypt-villus architecture in the small intestine is crucial for the structural integrity of the intestinal epithelium and maintenance of gut homeostasis. We utilized three-dimensional (3D) printing and inverse molding techniques to form three-dimensional (3D) spongy scaffold systems that resemble the intestinal crypt-villus microarchitecture. The scaffolds consist of silk fibroin protein with curved lumens with rows of protruding villi with invaginating crypts to generate the architecture. Intestinal cell (Caco-2, HT29-MTX) attachment and growth, as well as long-term culture support were demonstrated with cell polarization and tissue barrier properties compared to two-dimensional (2D) Transwell culture controls. Further, physiologically relevant oxygen gradients were generated in the 3D system. The various advantages of this system may be ascribed to the more physiologically relevant 3D environment, offering a system for the exploration of disease pathogenesis, host-microbiome interactions, and therapeutic discovery.
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Affiliation(s)
- Sara E Rudolph
- Department of Biomedical Engineering, Tufts University, 4 Colby Street, Medford, Massachusetts 02155, United States
| | - Brooke N Longo
- Department of Biomedical Engineering, Tufts University, 4 Colby Street, Medford, Massachusetts 02155, United States
| | - Megan W Tse
- Department of Biomedical Engineering, Tufts University, 4 Colby Street, Medford, Massachusetts 02155, United States
| | - Megan R Houchin
- Department of Biomedical Engineering, Tufts University, 4 Colby Street, Medford, Massachusetts 02155, United States
| | - Mina M Shokoufandeh
- Department of Biomedical Engineering, Tufts University, 4 Colby Street, Medford, Massachusetts 02155, United States
| | - Ying Chen
- Department of Biomedical Engineering, Tufts University, 4 Colby Street, Medford, Massachusetts 02155, United States
| | - David L Kaplan
- Department of Biomedical Engineering, Tufts University, 4 Colby Street, Medford, Massachusetts 02155, United States
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Garrahan M, Gehman S, Rudolph SE, Tenforde AS, Ackerman KE, Popp KL, Bouxsein ML, Sahni S. Serum 25-Hydroxyvitamin D is Associated With Bone Microarchitecture and Strength in a Multiracial Cohort of Young Adults. J Clin Endocrinol Metab 2022; 107:e3679-e3688. [PMID: 35766873 PMCID: PMC9387703 DOI: 10.1210/clinem/dgac388] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Indexed: 11/19/2022]
Abstract
PURPOSE To determine whether 25-hydroxyvitamin D (25-OH D) levels are associated with bone outcomes in a multiracial cohort of young adults. METHODS This cross-sectional study included 165 participants (83 men, 82 women, 18-30 years of age) who self-identified as Asian, Black, or White. We measured bone microarchitecture and strength of the distal radius and tibia using high-resolution peripheral quantitative computed tomography. We used linear regression to estimate the association between 25-OH D (ng/mL) and bone measurements, adjusting for race, sex, age, weight, height, calcium intake, physical activity, and season. RESULTS A total of 43.6% of participants were 25-OH D deficient (<20 ng/mL) with greater prevalence in Asian (38.9%) and Black (43.1%) compared with White (18.0%) participants (P < 0.001). At the distal radius, 25-OH D was positively associated with cortical area, trabecular density, cortical thickness, cortical porosity, and failure load (P < 0.05 for all). At the distal tibia, higher 25-OH D was associated with higher cortical area, trabecular density, trabecular number, failure load, and lower trabecular separation and cortical density (P < 0.05 for all). After multivariable adjustment, those with 25-OH D deficiency had generally worse bone microarchitecture than those with 25-OH D sufficiency. Black individuals had largely more favorable bone outcomes than Asian and White individuals, despite higher prevalence of 25-OH D deficiency. CONCLUSIONS We found a high prevalence of 25-OH D deficiency in a multiracial cohort of young adults. Lower 25-OH D was associated with worse bone outcomes at the distal radius and tibia at the time of peak bone mass, warranting further attention to vitamin D status in young adults.
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Affiliation(s)
- Margaret Garrahan
- Endocrine Unit, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Sarah Gehman
- Endocrine Unit, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Sara E Rudolph
- Endocrine Unit, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Adam S Tenforde
- Harvard Medical School, Boston, MA 02215, USA
- Spaulding Rehabilitation Hospital, Cambridge, MA 02138, USA
| | - Kathryn E Ackerman
- Endocrine Unit, Massachusetts General Hospital, Boston, MA 02114, USA
- Harvard Medical School, Boston, MA 02215, USA
- Boston Children’s Hospital, Boston, MA 02215, USA
| | - Kristin L Popp
- Endocrine Unit, Massachusetts General Hospital, Boston, MA 02114, USA
- Harvard Medical School, Boston, MA 02215, USA
- United StatesArmy Research Institute of Environmental Medicine, Natick, MA 01760, USA
| | - Mary L Bouxsein
- Correspondence: Mary L. Bouxsein, PhD, Center for Advanced Orthopaedic Studies, Beth Israel Deaconess Medical Center, RN115, 330 Brookline Avenue, Boston, MA 02215.
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Rudolph SE, Caksa S, Gehman S, Garrahan M, Hughes JM, Tenforde AS, Ackerman KE, Bouxsein ML, Popp KL. Physical Activity, Menstrual History, and Bone Microarchitecture in Female Athletes with Multiple Bone Stress Injuries. Med Sci Sports Exerc 2021; 53:2182-2189. [PMID: 33831898 PMCID: PMC8440446 DOI: 10.1249/mss.0000000000002676] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Bone stress injuries (BSIs) occur in up to 20% of runners and military recruits and those with a history of BSI have a 5-fold higher risk for a subsequent BSI. Yet, little is known about prior training, menstrual status and bone structure in runners who experience multiple BSIs. PURPOSE To determine differences in health and physical activity history, bone density, microarchitecture, and strength among female athletes with a history of multiple BSI, athletes with ≤1 BSI, and non-athletes. METHODS We enrolled 101 women (ages 18-32 years) for this cross-sectional study: non-athlete controls (n=17) and athletes with a history of ≥ 3 BSIs (n=21) or ≤1 BSI (n=63). We collected subjects' health and training history and measured bone microarchitecture of the distal tibia via high-resolution peripheral quantitative computed tomography (HR-pQCT) and areal bone mineral density (aBMD) of the hip and spine by dual-energy X-ray absorptiometry (DXA). RESULTS Groups did not differ according to age, BMI, age at menarche, aBMD, or tibial bone microarchitecture. Women with multiple BSIs had a higher prevalence of primary and secondary amenorrhea (p<0.01) compared to other groups. Total hours of physical activity in middle school were similar across groups; however, women with multiple BSIs performed more total hours of physical activity in high school (p=0.05), more hours of uniaxial loading in both middle school and high school (p=0.004, p=0.02) and a smaller proportion of multiaxial loading activity compared to other groups. CONCLUSION These observations suggest that participation in sports with multiaxial loading and maintaining normal menstrual status during adolescence and young adulthood may reduce the risk of multiple bone stress injuries.
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Affiliation(s)
- Sara E Rudolph
- Massachusetts General Hospital, Boston, MA United States Army Research Institute of Environmental Medicine, Natick MA Harvard Medical School, Boston MA Spaulding Rehabilitation Hospital, Cambridge MA Boston Children's Hospital, Boston MA Center for Advanced Orthopedic Studies, Beth Israel Deaconess Medical Center, Boston, MA
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Popp KL, Ackerman KE, Rudolph SE, Johannesdottir F, Hughes JM, Tenforde AS, Bredella MA, Xu C, Unnikrishnan G, Reifman J, Bouxsein ML. Changes in Volumetric Bone Mineral Density Over 12 Months After a Tibial Bone Stress Injury Diagnosis: Implications for Return to Sports and Military Duty. Am J Sports Med 2021; 49:226-235. [PMID: 33259223 DOI: 10.1177/0363546520971782] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
BACKGROUND Bone stress injuries (BSIs) occur in up to 20% of runners and military personnel. Typically, after a period of unloading and gradual return to weightbearing activities, athletes return to unrestricted sports participation or military duty approximately 4 to 14 weeks after a BSI diagnosis, depending on the injury location and severity. However, the time course of the recovery of the bone's mechanical competence is not well-characterized, and reinjury rates are high. PURPOSE To assess the bone microarchitecture and volumetric bone mineral density (vBMD) over 12 months after a tibial BSI diagnosis. STUDY DESIGN Case-control study; Level of evidence, 3. METHODS We enrolled 30 female athletes from the local community (aged 18-35 years) with a tibial BSI (grade ≥2 of 4 on magnetic resonance imaging) for this prospective observational study. Participants completed a baseline visit within 3 weeks of the diagnosis. At baseline and 6, 12, 24, and 52 weeks after the BSI diagnosis, we collected high-resolution peripheral quantitative computed tomography scans of the ultradistal tibia (4% of tibial length) of the injured and uninjured legs as well as pain and physical activity assessment findings. RESULTS From baseline to 12 weeks after the diagnosis, total, trabecular, and cortical vBMD declined by 0.58% to 0.94% (P < .05 for all) in the injured leg. Total and trabecular vBMD also declined by 0.61% and 0.67%, respectively, in the uninjured leg (P < .05 for both). At 24 weeks, mean values for all bone parameters were nearly equivalent to baseline values, and by 52 weeks, several mean values had surpassed baseline values. Of the 30 participants, 10 incurred a subsequent BSI during the course of the study, and 1 of these 10 incurred 2 subsequent BSIs. Participants who suffered an additional BSI were younger and had a later age of menarche, a greater incidence of previous fractures, and lower serum parathyroid hormone levels (P < .05 for all). CONCLUSION Bone density declined in both the injured and the uninjured legs and, on average, did not return to baseline for 3 to 6 months after a tibial BSI diagnosis. The observed time to the recovery of baseline vBMD, coupled with the high rate of recurrent BSIs, suggests that improved return-to-sports and military duty guidelines may be in order.
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Affiliation(s)
- Kristin L Popp
- Endocrine Unit, Massachusetts General Hospital, Boston, Massachusetts, USA.,Harvard Medical School, Boston, Massachusetts, USA.,Military Performance Division, United States Army Research Institute of Environmental Medicine, Natick, Massachusetts, USA
| | - Kathryn E Ackerman
- Endocrine Unit, Massachusetts General Hospital, Boston, Massachusetts, USA.,Harvard Medical School, Boston, Massachusetts, USA.,Boston Children's Hospital, Boston, Massachusetts, USA
| | - Sara E Rudolph
- Endocrine Unit, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Fjola Johannesdottir
- Harvard Medical School, Boston, Massachusetts, USA.,Center for Advanced Orthopaedic Studies, Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA
| | - Julie M Hughes
- Military Performance Division, United States Army Research Institute of Environmental Medicine, Natick, Massachusetts, USA
| | - Adam S Tenforde
- Harvard Medical School, Boston, Massachusetts, USA.,Spaulding Rehabilitation Hospital, Boston, Massachusetts, USA
| | - Miriam A Bredella
- Department of Radiology, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Chun Xu
- Biotechnology High Performance Computing Software Applications Institute, Department of Defense, Frederick, Maryland, USA
| | - Ginu Unnikrishnan
- Biotechnology High Performance Computing Software Applications Institute, Department of Defense, Frederick, Maryland, USA
| | - Jaques Reifman
- Biotechnology High Performance Computing Software Applications Institute, Department of Defense, Frederick, Maryland, USA
| | - Mary L Bouxsein
- Endocrine Unit, Massachusetts General Hospital, Boston, Massachusetts, USA.,Harvard Medical School, Boston, Massachusetts, USA.,Center for Advanced Orthopaedic Studies, Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA
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Caksa S, Yuan A, Rudolph SE, Yu EW, Popp KL, Bouxsein ML. Influence of soft tissue on bone density and microarchitecture measurements by high-resolution peripheral quantitative computed tomography. Bone 2019; 124:47-52. [PMID: 30998999 DOI: 10.1016/j.bone.2019.04.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 04/11/2019] [Accepted: 04/13/2019] [Indexed: 10/27/2022]
Abstract
High-resolution peripheral quantitative computed tomography (HR-pQCT) is a non-invasive method of measuring volumetric bone mineral density (vBMD) and microarchitecture at the distal radius and tibia. With increasing use of this technology, it is crucial to understand the potential impact of overlying soft tissue on the accuracy of HR-pQCT measures. Thus, we examined the effects of a simulated increase in adiposity (via 6- and 12-mm thick layers of overlying circumferential fat) on HR-pQCT measures of a hydroxyapatite (HA) phantom and in women (n = 20, aged 18-75 years). In the phantom, increasing the amount of overlying fat tissue led to a corresponding decrease in the mean measured density for each HA rod. In women, fat-layering led to a decrease in total vBMD (-2.9 to -3.7%, p < 0.001), cortical vBMD (-1.4% to -5.5%, p < 0.001), and estimated failure load (-1.4 to -5.7%, p = 0.002) at the radius, with similar changes in the tibia. Trabecular microarchitectural measurements were also impacted by simulated adiposity, with fat-layering leading to decreased trabecular thickness and separation and increased trabecular number at the radius (Δ's = 5 to 12%) with more pronounced differences at the tibia (Δ's = 14 to 40%). At the tibia, fat-layering also led to decreased cortical thickness and increased cortical porosity. Altogether, these results demonstrate that overlying adipose tissue can lead to artifacts in bone measurements by HR-pQCT, resulting in an underestimation of vBMD and generally, an overestimation of bone microarchitecture impairment. Therefore, soft tissue artifact should be considered when interpreting HR-pQCT results, particularly in those with high BMI and/or marked changes in adiposity.
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Affiliation(s)
- Signe Caksa
- Endocrine Unit, Massachusetts General Hospital, 50 Blossom Street, THR-1051 Boston, MA, USA
| | - Amy Yuan
- Endocrine Unit, Massachusetts General Hospital, 50 Blossom Street, THR-1051 Boston, MA, USA
| | - Sara E Rudolph
- Endocrine Unit, Massachusetts General Hospital, 50 Blossom Street, THR-1051 Boston, MA, USA
| | - Elaine W Yu
- Endocrine Unit, Massachusetts General Hospital, 50 Blossom Street, THR-1051 Boston, MA, USA; Harvard Medical School, 25 Shattuck St., Boston, MA, USA
| | - Kristin L Popp
- Endocrine Unit, Massachusetts General Hospital, 50 Blossom Street, THR-1051 Boston, MA, USA; United States Army Research Institute of Environmental Medicine, 10 General Greene Ave, Natick, MA, USA; Harvard Medical School, 25 Shattuck St., Boston, MA, USA.
| | - Mary L Bouxsein
- Endocrine Unit, Massachusetts General Hospital, 50 Blossom Street, THR-1051 Boston, MA, USA; Harvard Medical School, 25 Shattuck St., Boston, MA, USA; Center for Advanced Orthopedic Studies, Beth Israel Deaconess Medical Center, One Overland Street, Boston, MA, USA
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Rudolph SE, Kouba M, Hrdlicka P. [Severe corticoid-refractory autoimmune thrombocytopenia associated with mixed connective tissue disease (Sharp's syndrome). Treatment with rituximab]. Dtsch Med Wochenschr 2009; 134:1734-8. [PMID: 19718594 DOI: 10.1055/s-0029-1234008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
HISTORY AND CLINICAL FINDINGS An 18-year-old woman with mixed connective tissue disease (Sharp's syndrome), diagnosed two years earlier, was admitted because of severe thrombocytopenia. At that time the only symptom typical for collagen disease was Raynaud;s syndrome. The patient was in good general condition, the clinical examination revealed no signs of bleeding or of splenomegaly. INVESTIGATIONS Imaging procedures showed no abnormality. The platelets were decreased to 5 Gpt/l (normal range 150 - 400 Gpt/l). The bone marrow biopsy showed a secondary immunological thrombocytopenia with an increased number of megakaryocytes. TREATMENT AND CLINICAL COURSE Treatment with prednisolone, 100 mg/day, had no significant effect. As the patient refused splenectomy, treatment with rituximab 500 mg (375 mg/m2) per week was given over a period of four weeks, followed by azathioprine 2 x 50 mg/d. All tests demonstrated continuing increase of the platelet count up to 70 Gpt/l (normal range 150 - 400 Gpt/l). The signs of Raynaud;s syndrome also regressed. CONCLUSION Immunologic thrombocytopenia is a potentially life-threatening hematological manifestation of mixed connective tissue disease. If high-dosage prednisolone brings no response, a splenectomy is an efficacious treatment. B-cell depletion with rituximab offers another safe and adequate option.
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Affiliation(s)
- S E Rudolph
- Klinik für Innere Medizin/ Schwerpunkt Rheumatologie, Zeisigwaldkliniken Bethanien, Chemnitz.
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Sidman KR, Schwope AD, Steber WD, Rudolph SE. Use of synthetic polypeptides in the preparation of biodegradable delivery systems for narcotic antagonists. NIDA Res Monogr 1981; 28:214-231. [PMID: 6791006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The goal of this program was the development of biocompatible sustained-release systems that would release naltrexone at a rate of 20 to 25 microgram/hr for 30 days, and that would biodegrade within 90 days. The focus was on the use of macrocapsules prepared from synthetic polypeptides, specifically copolymers of glutamic acid and ethyl glutamate (i.e., Glu/EGlu copolymers). Tubular capsules prepared from 18/82 Glu/EGlu were the most promising systems developed. Capsules 1 cm in length, 0.19 cm in outside diameter, and 0.005 cm in wall thickness released naltrexone in mice at rates in the range of 20 to 40 microgram/hr for 18 days. The rates then decreased during the next 12 days as the capsules became exhausted of drug. These capsules were biocompatible and they appeared to biodegrade within 90 days. In general, the Glu/EGlu copolymers exhibit permeation and degradation rates that increase as the glutamic acid content is increased. Radiotracing studies revealed that the ultimate degradation product was carbon dioxide, which appeared in the expired air. This result is consistent with a polypeptide degradation process that involves hydrolysis of the ethyl esters followed by hydrolysis of the peptide bonds to produce glutamic acid, which enters the metabolic pool.
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