Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 14 de 14
Filtrar
Más filtros











Intervalo de año de publicación
1.
J Surg Res ; 302: 186-199, 2024 Aug 03.
Artículo en Inglés | MEDLINE | ID: mdl-39098117

RESUMEN

BACKGROUND: Stomach, small intestine, and colon have distinct patterns of contraction related to their function to mix and propel enteric contents. In this study, we aim to measure gut myoelectric activity in the perioperative course using external patches in an animal model. METHODS: Four external patches were placed on the abdominal skin of female Yucatan pigs to record gastrointestinal myoelectric signals for 3 to 5 d. Pigs subsequently underwent anesthesia and placement of internal electrodes on stomach, small intestine, and colon. Signals were collected by a wireless transmitter. Frequencies associated with peristalsis were analyzed for both systems for 6 d postoperatively. RESULTS: In awake pigs, we found frequency peaks in several ranges, from 4 to 6.5 cycles per minute (CPM), 8 to 11 CPM, and 14 to 18 CPM, which were comparable between subjects and concordant between internal and external recordings. The possible effect of anesthesia during the 1 or 2 h before surgical manipulation was observed as a 59% (±36%) decrease in overall myoelectric activity compared to the immediate time before anesthesia. The myoelectrical activity recovered quickly postoperatively. Comparing the absolute postsurgery activity levels to the baseline for each pig revealed higher overall activity after surgery by a factor of 1.69 ± 0.3. CONCLUSIONS: External patch measurements correlated with internal electrode recordings. Anesthesia and surgery impacted gastrointestinal myoelectric activity. Recordings demonstrated a rebound phenomenon in myoelectric activity in the postoperative period. The ability to monitor gastrointestinal tract myoelectric activity noninvasively over multiple days could be a useful tool in diagnosing gastrointestinal motility disorders.

2.
Pediatr Surg Int ; 39(1): 172, 2023 Apr 09.
Artículo en Inglés | MEDLINE | ID: mdl-37031428

RESUMEN

PURPOSE: Short bowel syndrome (SBS) is a devastating disease. We have proposed spring-mediated distraction enterogenesis for intestinal lengthening. Colonic lengthening is a potential treatment option for SBS to enhance fluid absorption capacity. We hypothesized that intraluminal spring-mediated colonic lengthening is associated with stem cell proliferation. METHODS: C57BL/6 mice underwent placement of a gelatin-encapsulated compressed or uncompressed nitinol spring in a cecal segment. Animals were given clear liquid diet until postoperative day (POD) 7, followed by regular diet until POD 14. Cecal lengths were measured at euthanasia, and tissue was formalin fixed for histological processing. For Lgr5-GFP mice, immunohistochemistry against GFP was performed to localize Lgr5+ cells within crypts. RESULTS: Significant cecal lengthening with compressed springs and shortening with uncompressed springs were observed on POD 7 and 14. Mucosa of the compressed spring group was significantly thicker on POD 14. The density of Lgr5+ cells within the crypts in the compressed spring groups was higher than that in the uncompressed spring groups on both POD 7 and 14. CONCLUSION: Expandable springs can be used to lengthen the colon in the mouse model. Colonic lengthening was associated with gradual mucosal thickening and correlated with an increased density of stem cells within the crypts.


Asunto(s)
Síndrome del Intestino Corto , Dispositivos de Expansión Tisular , Ratones , Animales , Expansión de Tejido , Yeyuno/cirugía , Ratones Endogámicos C57BL , Colon/cirugía , Síndrome del Intestino Corto/cirugía , Células Madre
3.
J Pediatr Surg ; 58(1): 89-93, 2023 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-36280466

RESUMEN

PURPOSE: The purpose of the study is to examine the long-term safety of an endoluminal bowel lengthening device prior to its use in the first human trial. In addition, device performance and natural passage will be evaluated. METHODS: Endoluminal lengthening springs were surgically placed into the jejunum of Yucatan minipigs using the Eclipse XL1 device. A matching internal control segment of jejunum was marked at the time of operation. Weekly weights and fluoroscopic studies were obtained to evaluate spring deployment and position until devices passed. Animals were euthanized at 28, 60, 90, and 180 days. At necropsy, length measurements were recorded, and histopathologic analysis was performed. RESULTS: There were no bowel obstructions or overt perforations attributable to the device. All surviving animals gained weight and were clinically thriving. All devices passed out of the rectum by 180 days. Bowel lengthening was seen in all experimental segments, and minimal fibrosis was observed by 180 days. CONCLUSION: Jejunal lengthening persisted after device had passed through the intestinal tract after 180 days. Early histopathologic changes of the jejunum during distraction enterogenesis normalized over time.


Asunto(s)
Síndrome del Intestino Corto , Dispositivos de Expansión Tisular , Animales , Yeyuno/cirugía , Recto/cirugía , Síndrome del Intestino Corto/cirugía , Porcinos Enanos , Dispositivos de Expansión Tisular/efectos adversos
4.
Pediatr Surg Int ; 39(1): 19, 2022 Nov 30.
Artículo en Inglés | MEDLINE | ID: mdl-36449179

RESUMEN

PURPOSE: Spring-mediated distraction enterogenesis has proven to be successful for intestinal lengthening. We aimed to evaluate the effect of spring diameter mismatch on intestinal adaptation. METHODS: Juvenile mini-Yucatan pigs underwent placement of compressed nitinol springs with diameter of 10, 11, or 12 mm into the ileal lumen. Pigs were euthanized on postoperative day 7. The lengths, histology, total area of blood vessels, and enteric ganglia were evaluated. RESULTS: All spring groups exhibited significant ileal lengthening. Across the different diameters, spring-expanded segments were similar in terms of ileal lengthening, crypt height, muscular thickness, blood vessels, and enteric ganglia area. CONCLUSION: Spring-mediated distraction enterogenesis is successful in the porcine ileum. A smaller diameter spring is as effective as a larger diameter spring in lengthening the ileum. Springs of varying diameters result in comparable structural changes in the ileum.


Asunto(s)
Íleon , Animales , Porcinos , Humanos , Íleon/cirugía , Periodo Posoperatorio
5.
J Pediatr Surg ; 57(7): 1377-1381, 2022 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-34740442

RESUMEN

BACKGROUND/PURPOSE: Distraction enterogenesis with intraluminal spring technology has been successfully used to lengthen segments of murine small intestine. We hypothesized that biocompatible springs could also be used to lengthen murine large intestine. METHODS: Age and weight matched C57BL/6 mice underwent surgical insertion of nitinol spring-loaded capsules into the cecum. Segment lengths were measured at initial spring placement and at euthanasia after 7 and 14 days. Histologic adaptations were evaluated at scarification. RESULTS: Cecal segments loaded with compressed springs lengthened an average of 150%, which was significantly longer than control segments loaded with either empty capsules or uncompressed springs. Muscularis layers tended to be thicker in the compressed spring groups compared to control groups. CONCLUSIONS: Insertion of a compressed nitinol spring into the cecum results in significant colonic lengthening in a mouse model. The ability to increase cecum length serves as proof of concept that distraction enterogenesis technology may be feasibly applied to large intestinal models. The use of distraction enterogenesis technology shows promise for application to clinical models in the treatment of pediatric intestinal disease.


Asunto(s)
Síndrome del Intestino Corto , Dispositivos de Expansión Tisular , Animales , Cápsulas , Colon/cirugía , Humanos , Yeyuno/cirugía , Ratones , Ratones Endogámicos C57BL , Síndrome del Intestino Corto/cirugía , Expansión de Tejido/métodos
6.
J Pediatr Surg ; 56(7): 1192-1198, 2021 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-33836847

RESUMEN

INTRODUCTION: short bowel syndrome is marked by inadequate intestinal surface area to absorb nutrients. Current treatments are focused on medical management and surgical reconfiguration of the dilated intestine. We propose the use of spring-mediated distraction enterogenesis as a novel intervention to increase intestinal length. Given our previous success lengthening intestinal segments using springs with spring constant ~7 N/m that exerts 0.46 N or higher, we sought to determine the minimal force needed to lengthen porcine small intestinal segments, and to explore effects on intestine over time. METHODS: Juvenile Yucatan pigs underwent laparotomy with enterotomy to introduce nitinol springs intraluminally (n = 21 springs). Bowel segments (control, spring-distracted) were retrieved on post-operative day (POD) 7 and 14, and lengths measured. Thickness of cross-sectional intestinal layers were measured using H&E, and submucosal collagen fiber orientation measured using trichrome stained sections. RESULTS: all pigs survived to POD7 and 14. Spring constants of at least 2 N/m exerting a minimum force of 0.10 N significantly lengthened intestinal segments (p <0.0001). The stronger the spring force, the greater the induced thickness of various intestinal layers at POD7 and 14. Collagen fiber orientation was also more disordered because of stronger springs. CONCLUSION: a spring constant of approximately 2 N/m exerting 0.10 N and greater significantly lengthens intestinal segments and stimulates intestinal structural changes at POD7 and 14. This suggests a decreased force is capable of inducing spring-mediated distraction enterogenesis.


Asunto(s)
Síndrome del Intestino Corto , Dispositivos de Expansión Tisular , Animales , Estudios Transversales , Intestino Delgado/cirugía , Yeyuno/cirugía , Síndrome del Intestino Corto/cirugía , Porcinos , Expansión de Tejido
7.
J Pediatr Surg ; 56(1): 5-10, 2021 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-33143878

RESUMEN

BACKGROUND: Short gut syndrome, a condition characterized by inadequate absorption of nutrients owing to decreased bowel length, has minimal avenues for treatment. We have proposed spring-mediated distraction enterogenesis to lengthen bowel in porcine jejunum as a treatment for short gut. We aim to evaluate the extent of mesenteric neovascularization in segments of lengthened bowel via spring-mediated enterogenesis. METHODS: Female juvenile Yucatan pigs underwent laparotomy and insertion of gelatin-encapsulated compressed nitinol springs, held in place with plication sutures, into the jejunum. At surgery and sacrifice, macroscopic mesenteric blood vessels were counted between the plication sites. Histologic samples of the mesentery were obtained to evaluate microscopic vasculature. RESULTS: A statistically significant increase in macroscopic mesenteric blood vessels was seen after intestinal lengthening (before: 1.9 ±â€¯0.7 vessels, after: 4.7 ±â€¯1.2 vessels, p = 0.001). A statistical significance is also seen in the density of arterioles (control: 3.0 ±â€¯3.0 vessels/mm, spring: 7.0 ±â€¯9.0 vessels/mm, p = 0.01) and venules (control: 4.0 ±â€¯3.0 vessels/mm, spring: 8.0 ±â€¯8.0 vessels/mm, p = 0.003). CONCLUSION: Intestinal segments lengthened by intraluminal springs demonstrated total greater number of macroscopic vessels and microscopic blood vessels per length of mesentery as compared to control. This suggests local changes within the mesentery to recruit blood supply to growing intestine. LEVEL OF EVIDENCE: N/A TYPE OF STUDY: Treatment study.


Asunto(s)
Síndrome del Intestino Corto , Dispositivos de Expansión Tisular , Animales , Femenino , Intestinos/cirugía , Mesenterio/cirugía , Síndrome del Intestino Corto/cirugía , Porcinos , Expansión de Tejido
8.
J Pediatr Surg ; 56(2): 346-351, 2021 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-32709529

RESUMEN

BACKGROUND/PURPOSE: Intraluminal springs have recently been shown to lengthen segments of intestine in a process known as distraction enterogenesis. We hypothesized that biocompatible springs could be used to lengthen defunctionalized murine small intestine and would lead to identifiable intestinal adaptations at the molecular level. METHODS: Age and weight matched C57BL/6 mice underwent surgical insertion of nitinol spring-loaded capsules into a Roux limb of jejunum. Segment lengths were measured at initial spring placement and at euthanasia after 14 and 21 days. Histology and gene expression of the Roux limb were evaluated at scarification and compared to untreated control segments. RESULTS: Intestinal segments loaded with compressed springs lengthened an average of 240%, which was significantly longer than control segments loaded with either empty capsules or uncompressed springs. Muscularis thickening was greater in spring-treated mice compared to controls without springs. Crypt depth and Lgr5+ expression was greater in mice that received compressed spring treatments when compared to control groups. CONCLUSIONS: Insertion of a compressed nitinol spring into a Roux limb results in significant intestinal lengthening, smooth muscle thickening, and Lgr5+ expression in a mouse model. The ability to increase small bowel length in a defunctionalized murine model may be used to understand the mechanism of distraction enterogenesis.


Asunto(s)
Intestinos/cirugía , Síndrome del Intestino Corto , Dispositivos de Expansión Tisular , Animales , Yeyuno/cirugía , Ratones , Ratones Endogámicos C57BL , Síndrome del Intestino Corto/cirugía , Expansión de Tejido
9.
J Pediatr Surg ; 55(12): 2791-2796, 2020 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-32253016

RESUMEN

PURPOSE: One in 5000 newborns is diagnosed with Hirschsprung disease each year in the United States. The potential of employing neural crest stem cells to restore the enteric nervous system has been investigated. Skin-derived precursor cells (SKPs) are multipotent progenitor cells that can differentiate into neurons and gliocytes in vitro and generate enteric ganglion-like structures in rodents. Here we examined the behavior of human SKPs (hSKPs) after their transplantation into a large animal model of colonic aganglionosis. METHODS: Juvenile minipigs underwent a chemical denervation of the colon to establish an aganglionosis model. The hSKPs were generated from human foreskin and were cultured in neuroglial-selective medium. Cells were labeled with a fluorescent dye and were injected into the porcine aganglionic colon. After one week, transplanted hSKPs were assessed by immunofluorescence for markers of multipotency and neuroglial differentiation. RESULTS: In culture, hSKPs expressed nestin and S100b indicative of neuroglial precursors. After xenografting in pigs, hSKPs were identified in the myenteric and submucosal plexuses of the colons. The hSKPs expressed nestin and early neuroglial differentiation markers. CONCLUSIONS: Human SKPs transplanted into aganglionic colon demonstrated immunophenotypes of neuroglial progenitors, suggesting their potential use for Hirschsprung disease.


Asunto(s)
Enfermedad de Hirschsprung , Animales , Diferenciación Celular , Células Cultivadas , Sistema Nervioso Entérico , Enfermedad de Hirschsprung/cirugía , Humanos , Recién Nacido , Plexo Submucoso , Porcinos , Porcinos Enanos , Trasplante Heterólogo
10.
J Pediatr Surg ; 55(1): 158-163, 2020 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-31676077

RESUMEN

BACKGROUND: Spring-mediated intestinal lengthening has been studied in numerous animal models to effectively achieve up to a 3-fold increase in length. In this study we are interested in optimizing this method of spring lengthening. METHODS: Juvenile mini-Yucatan pigs underwent laparotomy for spring implantation. Springs were secured by plicating the intestine around the springs. In one set of experiments, varying degrees of plication were compared to determine the necessary narrowing needed to confine the spring. In another set of experiments, dissolvable sutures were used for the plication to allow for spontaneous spring passage postoperatively. Intestinal segments were retrieved and evaluated for lengthening and histological changes. RESULTS: Pigs tolerated their diet advancement to a regular diet postoperatively. 10% plication resulted in a 1.3-fold increase in length, while 50% plication resulted in a 2.7-fold increase in length (p<0.05). At two months postoperatively, the majority of springs had safely passed out of the intestine. All lengthened intestine showed significant growth histologically. CONCLUSIONS: A 50% reduction in lumen diameter achieves optimal spring-mediated intestinal lengthening. Springs can safely pass out of the intestine, thus avoiding a second operation for spring removal. These results may be important in developing future therapies for short bowel syndrome. LEVEL OF EVIDENCE: Level I experimental study.


Asunto(s)
Yeyuno/cirugía , Dispositivos de Expansión Tisular , Expansión de Tejido/instrumentación , Animales , Femenino , Modelos Animales , Periodo Posoperatorio , Síndrome del Intestino Corto/cirugía , Suturas , Porcinos , Porcinos Enanos , Expansión de Tejido/métodos
11.
J Pediatr Surg ; 55(1): 194-200, 2020 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-31704043

RESUMEN

BACKGROUND: Hirschprung's disease is characterized by aganglionic bowel and often requires surgical resection. Cell-based therapies have been investigated as potential alternatives to restore functioning neurons. Skin-derived precursor cells (SKPs) differentiate into neural and glial cells in vitro and generate ganglion-like structures in rodents. In this report, we aimed to translate this approach into a large animal model of aganglionosis using autologous transplantation of SKPs. METHODS: Juvenile pigs underwent skin procurement from the shoulder and simultaneous chemical denervation of an isolated colonic segment. Skin cells were cultured in neuroglial-selective medium and labeled with fluorescent dye for later identification. The cultured SKPs were then injected into the aganglionic segments of colon, and the specimens were retrieved within seven days after transplantation. SKPs in vitro and in vivo were assessed with histologic samples for various immunofluorescent markers of multipotency and differentiation. SKPs from the time of harvest were compared to those at the time of injection using PCR. RESULTS: Prior to transplantation, 72% of SKPs stained positive for nestin and S100b, markers of neural and glial precursor cells of neural crest origin, respectively. Markers of differentiated neurons and gliocytes, TUJ1 and GFAP, were detected in 47% of cultured SKPs. After transplantation, SKPs were identified in both myenteric and submucosal plexuses of the treated colon. Nestin co-expression was detected in the SKPs within the aganglionic colon in vivo. Injected SKPs appeared to migrate and express early neuroglial differentiation markers. CONCLUSIONS: Autologous SKPs implanted into aganglionic bowel demonstrated immunophenotypes of neuroglial progenitors. Our results suggest that autologous SKPs may be potentially useful for cell-based therapy for patients with enteric nervous system disorders. TYPE OF STUDY: Basic science.


Asunto(s)
Diferenciación Celular , Enfermedad de Hirschsprung/terapia , Piel/citología , Trasplante de Células Madre , Células Madre/metabolismo , Animales , Células Cultivadas , Colon , Modelos Animales de Enfermedad , Proteína Ácida Fibrilar de la Glía/metabolismo , Enfermedad de Hirschsprung/inducido químicamente , Plexo Mientérico/patología , Nestina/metabolismo , Neuronas/metabolismo , Subunidad beta de la Proteína de Unión al Calcio S100/metabolismo , Células Madre/fisiología , Plexo Submucoso/patología , Porcinos , Trasplante Autólogo , Tubulina (Proteína)/metabolismo
12.
Surgery ; 165(2): 389-392, 2019 02.
Artículo en Inglés | MEDLINE | ID: mdl-30217395

RESUMEN

BACKGROUND: Short bowel syndrome is a condition with substantial morbidity and mortality, yet definitive therapies are lacking. Distraction enterogenesis uses mechanical force to "grow" new intestine. In this study, we examined whether intestinal plication can be used to safely achieve spring-mediated intestinal lengthening in a functioning segment of jejunum in its native position. METHODS: A total of 12 juvenile, miniature Yucatan pigs underwent laparotomy to place either compressed springs or expanded springs within a segment of jejunum (n = 6 per group). The springs were secured within the jejunum by performing intestinal plication to narrow the intestinal lumen around the spring. After 3 weeks, the jejunum was retrieved and examined for lengthening and for histologic changes. RESULTS: There were no intraoperative or postoperative complications, and the pigs tolerated their diets and gained weight. Segments of jejunum containing expanded springs showed no significant change in length over the 3 weeks. In contrast, jejunum containing compressed springs showed nearly a 3-fold increase in length (P < .001). Histology of the retrieved jejunum showed a significant increase in thickness of the muscularis propria and in crypt depth relative to normal jejunum. CONCLUSION: Intestinal plication is effective in securing endoluminal springs to lengthen the jejunum. This approach is a clinically relevant model because it allows for normal GI function and growth of animals during intestinal lengthening, which may be useful in lengthening intestine in patients with short bowel syndrome.


Asunto(s)
Yeyuno/cirugía , Dispositivos de Expansión Tisular , Expansión de Tejido/métodos , Animales , Procedimientos Quirúrgicos del Sistema Digestivo/instrumentación , Procedimientos Quirúrgicos del Sistema Digestivo/métodos , Yeyuno/anomalías , Modelos Animales , Síndrome del Intestino Corto/cirugía , Porcinos
13.
J Pediatr Surg ; 54(1): 39-43, 2019 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-30361072

RESUMEN

BACKGROUND: Short bowel syndrome is a debilitating condition with few effective treatments. Spring-mediated distraction enterogenesis can be used to lengthen intestine. The purpose of this study is to determine whether multiple springs in series can safely increase the total amount of lengthening. METHODS: Juvenile mini-Yucatan pigs each received three nitinol springs placed within their jejunum. Plication was used to narrow the intestine around each spring to secure them. Compressed springs were used in the experimental group, while uncompressed springs were used in the control group. The intestine was examined 3 weeks later for lengthening and histologic changes. RESULTS: All pigs tolerated diets postoperatively with continued weight gain, and no dilation or obstruction of the intestine was observed. Segments of intestine that contained compressed springs had a significant increase in length from 2.5 cm to 3.9 ±â€¯0.2 cm per spring, compared to segments containing control springs that showed no change (p < 0.001). CONCLUSIONS: Intestinal plication can be safely used to secure multiple springs in series to achieve intestinal lengthening without compromising intestinal function. Using several springs at once allows for a greater amount of total lengthening. This is a promising model that has potential in the treatment of short bowel syndrome.


Asunto(s)
Procedimientos Quirúrgicos del Sistema Digestivo/métodos , Intestinos/cirugía , Síndrome del Intestino Corto/cirugía , Dispositivos de Expansión Tisular , Aleaciones/farmacología , Animales , Procedimientos Quirúrgicos del Sistema Digestivo/instrumentación , Porcinos
14.
J Pediatr Surg ; 53(9): 1806-1810, 2018 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-29352575

RESUMEN

BACKGROUND: Spring-mediated distraction enterogenesis has been shown to increase the length of an intestinal segment. The goal of this study is to use suture plication to confine a spring within an intestinal segment while maintaining luminal patency to the rest of the intestine. METHODS: Juvenile mini-Yucatan pigs underwent placement of nitinol springs within a defunctionalized Roux limb of jejunum. A 20 French catheter was passed temporarily, and sutures were used to plicate the intestinal wall around the catheter at both ends of the encapsulated spring. Uncompressed springs placed in plicated segments and springs placed in nonplicated segments served as controls. The intestine was examined approximately 3 weeks after spring placement. RESULTS: In the absence of plication, springs passed through the intestine within a week. Double plication allowed the spring to stay within the Roux limb for 3 weeks. Compared to uncompressed springs that showed no change in the length of plicated segments, compressed springs caused a significant 1.7-fold increase in the length of plicated segments. CONCLUSIONS: Intestinal plication is an effective method to confine endoluminal springs. The confined springs could lengthen intestine that maintains luminal patency. This approach may be useful to lengthen intestine in patients with short bowel syndrome. LEVEL OF EVIDENCE: Level I Experimental Study.


Asunto(s)
Yeyuno/cirugía , Síndrome del Intestino Corto/cirugía , Dispositivos de Expansión Tisular , Expansión de Tejido/métodos , Aleaciones , Animales , Catéteres , Procedimientos Quirúrgicos del Sistema Digestivo/instrumentación , Procedimientos Quirúrgicos del Sistema Digestivo/métodos , Femenino , Yeyuno/anomalías , Modelos Animales , Porcinos , Porcinos Enanos , Expansión de Tejido/instrumentación
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA