Regenerative process evaluation of neuronal subclasses in chagasic patients with megacolon.

Chagas' disease is one of the most serious parasitic diseases of Latin America, with a social and economic impact far outweighing the combined effects of other parasitic diseases such as malaria, leishmaniasis and schistosomiasis. In the chronic phase of this disease, the destruction of enteric nervous system (ENS) components leads to megacolon development. Previous data presented that the regeneration tax in the ENS neurons is augmented in chagasic patients. Although, there are several neuronal types with different functions in the intestine a detailed study about the regeneration of every neuronal type was never performed before. Therefore, the aim of this study was to evaluate the regeneration tax of every neuronal cell type in the ENS from chagasic patients with megacolon and non-infected individuals. A neuronal regeneration marker (GAP-43) was used in combination with a pan-neuronal marker (Peripherin) and several neuropeptides markers (cChat, Substance P, NPY, VIP and NOS), and it was considered as positive just with the combination of these markers. Our results demonstrated that the regeneration levels of cChat, Substance P, and NPY were similar in chagasic patients and non-infected individuals. However, levels of VIP and NOS neuropeptides were increased in chagasic patients when compared with non-infected individuals. We believe that the augment in the regeneration occur due to an increased destruction of selective neuronal types. These results corroborates with previous studies that pointed out to selective destruction of VIP and NOS neurons in chagasic patients.

Administration of noradrenaline in the autonomic ganglia modifies the testosterone release from the testis using an ex vivo system.

The male gonad receives nerve fibres from the autonomic ganglionic system. These fibres converge on the testis along two pathways, the superior and the inferior spermatic nerves. The superior spermatic nerve runs from the superior mesenteric ganglion alongside the testicular artery, whereas the inferior spermatic nerve originates in inferior mesenteric ganglion, accompanies the vas deferens and penetrates the inferior pole of the testis. The aim of this work was to evaluate androgen release after the addition of noradrenaline or adrenoreceptor antagonists (propranolol or phentolamine) to the ganglionic compartment. An ex vivo system used in a previous work was incubated in two separate containers, one for the testis and the other for the ganglion. Both organs remain interconnected (as in vivo) by the respective spermatic nerve. When noradrenaline was added to the inferior mesenteric ganglion, testosterone release in the gonad container underwent a progressive and significant increment. Propranolol diminishes and phentolamine increases the androgen release. When using the superior mesenteric ganglion, no changes were observed. These results indicate that the ganglionic stimulation of the autonomic system clearly participates in testosterone release from the testis. This effect depends on the ganglion involved. These results make it evident that not only the classical and well-known hypothalamus-hypophysial axis, but also the peripheral nervous system, via the autonomic ganglia, are directly involved in the endocrine control of the testis.

Effects of ACE inhibition and beta-blockade on plasminogen activator inhibitor-1 and transforming growth factor-beta1 in carotid glomus and autonomic ganglia in hypertensive rats.

BACKGROUND: Previous studies have demonstrated a high correlation between arterial hypertension and the development of lesions in the carotid glomus (CG) and autonomic ganglia (AG), characterized by extracellular matrix (ECM) expansion and reduction in the number of AG neurons. Because lowering blood pressure (BP) is the first step in controlling the deleterious effects of arterial hypertension, the objective was to evaluate possible differences between the beta-blocker atenolol (AT) and the angiotensin-converting enzyme (ACE) inhibitor ramipril (RAM) regarding a protective role on CG and AG, as target organs in the spontaneously hypertensive rat (SHR). METHODS: Male 12-week-old SHR and Wistar-Kyoto rats (WKY) were divided into SHR; SHR-RAM, 1 mg/kg/d; SHR-AT, 100 mg/kg/d; and WKY rats. After 6 months, the animals were sacrificed and CG and AG were processed by hematoxylin and eosin (H&E) and Masson's trichrome and immunohistochemistry (transforming growth factor-beta(1) and plasminogen activator inhibitor-1). RESULTS: At the end of the experiment, SHR-AT and SHR-RAM showed a similar control in BP compared with SHR. However, SHR-RAM presented a significant reduction in ECM expansion in CG, AG, and autonomic nerves. Moreover, the number of neurons in AG was preserved with AT and even more with RAM, when compared with SHR group. Transforming growth factor-beta(1) and plasminogen activator inhibitor-1 were increased in CG and AG in SHR and in SHR-AT, whereas SHR-RAM showed a similar expression to the WKY group. CONCLUSIONS: According to these results, RAM but not AT provided a significant protective role against structural changes in CG as well as in AG caused by arterial hypertension in SHR. This effect seems to be independent of BP reduction.

Efectos del losartán sobre el glomus carotídeo en ratas normotensas adultas / Effects of losartan on the carotid glomus in adult normotensive rats

Recientemente comunicamos lesiones graves en el glomus carotídeo y los ganglios autonómicos de ratas SHR y sugerimos que este efecto se debía más al aumento de la presión arterial que al envejecimiento. Posteriormente demostramos, en SHR, que el ramipril, en comparación con el atenolol, ejerce un efecto protector sobre estas estructuras más allá de la reducción de la presión arterial. Teniendo en cuenta que no existen trabajos que describan los cambios que origina el bloqueo AT1 sobre la morfología del glomus en ratas normotensas, se realizó el presente estudio con el objetivo de evaluar el efecto del losartán sobre esta estructura de ratas Wistar macho tratadas durante 8 meses. Se emplearon 14 ratas de 4 semanas de edad, divididas en grupos control y losartán (10 mg/kg/día en el agua de bebida). La presión sistólica (PAS) se registró al inicio y luego mensualmente. A la edad de 9 meses se sacrificaron las ratas y se extrajeron los glomus carotídeos, se tiñeron con hematoxilina-eosina y tricrómico de Masson y se procesaron para histomorfometría con un analizador de imágenes. El grupo control registró una PAS de 115 ± 8,1, mientras que en el grupo losartán fue de105 ± 8,3 mm Hg (p = 0,0375). Histomorfométricamente, el grupo tratado mostró un área mayor del glomus con respecto al control (497.931 ± 48.783 versus 59.668 ± 6.196 µm2; p <0,0001) y una relación pared/luz en las arteriolas glómicas de 0,7 ± 0,1 versus 2,7 ± 0,6,respectivamente (p < 0,0001). El grupo control mostró disminución del área glómica y un aumento de la relación pared/luz, lo cual sugiere que la atrofia de las estructuras estudiadas a través del aumento de la edad se vincula con el aporte nutricio arterial.

Efectos del losartán sobre el glomus carotídeo en ratas normotensas adultas / Effects of losartan on the carotid glomus in adult normotensive rats

Recientemente comunicamos lesiones graves en el glomus carotídeo y los ganglios autonómicos de ratas SHR y sugerimos que este efecto se debía más al aumento de la presión arterial que al envejecimiento. Posteriormente demostramos, en SHR, que el ramipril, en comparación con el atenolol, ejerce un efecto protector sobre estas estructuras más allá de la reducción de la presión arterial. Teniendo en cuenta que no existen trabajos que describan los cambios que origina el bloqueo AT1 sobre la morfología del glomus en ratas normotensas, se realizó el presente estudio con el objetivo de evaluar el efecto del losartán sobre esta estructura de ratas Wistar macho tratadas durante 8 meses. Se emplearon 14 ratas de 4 semanas de edad, divididas en grupos control y losartán (10 mg/kg/día en el agua de bebida). La presión sistólica (PAS) se registró al inicio y luego mensualmente. A la edad de 9 meses se sacrificaron las ratas y se extrajeron los glomus carotídeos, se tiñeron con hematoxilina-eosina y tricrómico de Masson y se procesaron para histomorfometría con un analizador de imágenes. El grupo control registró una PAS de 115 ± 8,1, mientras que en el grupo losartán fue de105 ± 8,3 mm Hg (p = 0,0375). Histomorfométricamente, el grupo tratado mostró un área mayor del glomus con respecto al control (497.931 ± 48.783 versus 59.668 ± 6.196 Am2; p <0,0001) y una relación pared/luz en las arteriolas glómicas de 0,7 ± 0,1 versus 2,7 ± 0,6,respectivamente (p < 0,0001). El grupo control mostró disminución del área glómica y un aumento de la relación pared/luz, lo cual sugiere que la atrofia de las estructuras estudiadas a través del aumento de la edad se vincula con el aporte nutricio arterial. (AU)

Plasminogen activator inhibitor-1 and transforming growth factor-beta 1 in carotid glomus and autonomic ganglia from spontaneously hypertensive rats.

BACKGROUND: Baroreflex and chemoreflex mechanisms play an important role in the dynamic adjustments of circulation and ventilation during daily life. Recently, we have observed atrophy and marked fibrosis in carotid glomus (CG) from old patients with carotid atherosclerosis who died following stroke. However, a possible limitation to interpretation of the results in that study was the superposition of arterial hypertension, atherosclerosis and aging in the patients. Taking this into account, spontaneously hypertensive rats (SHR) were used in order to study the CG in an experimental model with only hemodynamic stress. OBJECTIVE: To evaluate whether transforming growth factor-beta 1 (TGF-beta 1) and plasminogen activator inhibitor-1 (PAI-1) were involved in the extracellular matrix expansion in CG and autonomic ganglia (AG) in young, male, adult SHR. METHODS: Male SHR (n = 10) and Wistar-Kyoto (WKY) rats (n = 10) were used. Systolic blood pressure (SBP) was measured monthly up to 8 months of age, when the animals were killed; then, CG and AG were excised and processed for light microscopy and immunohistochemistry (TGF-beta 1, PAI-1 and protein S100). RESULTS: SBP was highly correlated (P < 0.01) with CG fibrosis (r = 0.90), AG fibrosis (r = 0.96) and neuron number (r = -0.97). PAI-1 and TGF-beta 1 in CG and AG were significantly increased (P < 0.01) in SHR. CONCLUSION: Severe damage was observed in CG and AG in SHR, which was, in addition, correlated with SBP. These results suggest that permanent high blood pressure produces remarkable lesions in these structures, even when the animals are not old. In view of the fact that CG and AG are of utmost importance in the genesis of cardiocirculatory reflexes, they might be considered as 'target organs' in arterial hypertension.

Structural organization of the enteric nervous system in the cattle esophagus revealed by wholemount immunohistochemistry.

In ruminants the motility patterns of the esophageal tube are characterized by physiological regurgitations including both anterograde and retrograde peristaltic movements. These complex motor functions require an elaborated enteric nervous system (ENS) for the generation of the underlying intrinsic reflex circuits. The structural organization of the esophageal ENS was studied in fetuses of cattle (n=6) by means of wholemount preparations obtained from different segments of the esophagus. Demonstration of nerve cells, ganglia and nerve fibers strands (NFS) was achieved by immunohistochemistry using the general neuronal marker protein gene product (PGP) 9.5. The myenteric plexus represented the most prominent nerve network composed of differently shaped ganglia and interconnecting NFS. Frequenitly the myenteric ganglia were arranged in two separate layers interweaving with the adjacent muscle coat. From the cervical towards the thoracic segment of the esophagus the density and size of myenteric ganglia increased and the NFS exhibited thicker diameters. The submucosal and mucosal plexus consisted of NFS ramifying throughout the tela submucosa and the lamina propria mucosae. The networks showed no evidence of ganglia nor single nerve cells. The findings illustrate that intrinsic esophageal nerve cells are confined to the myenteric plexus. Since the esophageal tube has no secretory functions, secreto-motor neurons are not required in the submucosal and mucosal plexus layers. The structural organization of the intramural nerve networks--in particular the specific arrangement of the myenteric plexus--reflects the substantial contribution of the esophageal ENS to the coordination and mediation of esophageal motility in ruminants.