Abnormalities In Smooth Muscle Cells Research Articles

Sufficient Cav-1 levels in the endothelium are critical for the maintenance of the neurovascular unit in the retina

BackgroundCaveolin-1 (Cav-1) is a pivotal protein in the plasma membrane. Studies on homozygous Cav-1 deficient mice revealed that Cav-1 is essential for endothelial function and angiogenesis in the retina. However, whether a reduction in Cav-1 content hampers the neurovascular unit (NVU) in the retina is unclear. Thus, this study examines the NVU in the retinas of heterozygous Cav-1 deficient (Cav-1+/−) mice and analyzes possible underlying mechanisms.MethodsThe vascular, glial and neuronal components in the retina were evaluated using retinal morphometry, whole mount retinal immunofluorescence staining, histological analysis and optical coherence tomography. In addition, immunoblotting and immunofluorescence staining, subcellular fractionation, biotin labeling of cell surface proteins, and proximity ligation assay were employed to detect expression and localization of proteins in the retina or endothelial cells (ECs) upon knockdown of Cav-1 with Cav-1 siRNA.ResultsCav-1+/− retinas showed a significant reduction in pericyte coverage along with an increase in acellular capillaries compared to controls at 8 months of age, but not at 1 month. A significant loss and obvious morphological abnormalities of smooth muscle cells were observed in 8-month-old Cav-1+/− retinal arterioles. Macroglial and microglial cells were activated in the Cav-1+/− retinas. A transient significant delay in retinal angiogenesis was detected in Cav-1+/− retinas at p5, which was however no longer detectable at p10. The Cav-1+/− retinas displayed increased vascular permeability and a notable reduction in VEGFR2 content at 8 months. In vitro, siRNA-mediated knockdown experiments in ECs revealed that the loss of Cav-1 in ECs resulted in decreased levels of VEGFR2, VE-Cadherin and their interaction at the plasma membrane as well.ConclusionOur results indicate that a sufficient Cav-1 level over 50% of its normal abundance is vital for the proper localization of VEGFR2 and VE-cadherin, likely in a complex, at the plasma membrane, which is essential for the maintenance of normal NVU in the retina.

Persistent bowel dysfunction after surgery for Hirschsprung's disease: A neuropathological perspective.

Hirschsprung’s disease (HD) is a congenital disorder, characterized by aganglionosis in the distal part of the gastrointestinal tract. Despite complete surgical resection of the aganglionic segment, both constipation and fecal incontinence persist in a considerable number of patients with limited treatment options. There is growing evidence for structural abnormalities in the ganglionic bowel proximal to the aganglionosis in both humans and animals with HD, which may play a role in persistent bowel dysfunction. These abnormalities include: (1) Histopathological abnormalities of enteric neural cells; (2) Imbalanced expression of neurotransmitters and neuroproteins; (3) Abnormal expression of enteric pacemaker cells; (4) Abnormalities of smooth muscle cells; and (5) Abnormalities within the extracellular matrix. Hence, a better understanding of these previously unrecognized neuropathological abnormalities may improve follow-up and treatment in patients with HD suffering from persistent bowel dysfunction following surgical correction. In the long term, further combination of clinical and neuropathological data will hopefully enable a translational step towards more individual treatment for HD.

Ultrastructural Study of Clitoral Cavernous Tissue and Clitoral Blood Flow From Type 1 Diabetic Premenopausal Women on Phosphodiesterase-5 Inhibitor

BackgroundThe effects of phosphodiesterase-type 5 (PDE5) inhibitors on the in vivo clitoral structure of women with diabetes have never been investigated. AimTo study the in vivo structural and hemodynamic changes of the clitoris in premenopausal women with type 1 diabetes on PDE5 inhibitors. Methods38 premenopausal women with type 1 diabetes aged 36 -46 years. A randomized 1:1 study design was used: Study Group (group A) on Tadalafil 5 mg daily, and control group (group B). Blood samples were taken from each woman to measure HbA1c, testosterone, and Free Androgen Index. The women underwent microbiopsy of the clitoral body by means of semiautomatic gun during total anesthesia for surgery therapy of a benign gynecological pathology. The tissue removed was processed for electron microscopy. Translabial color Doppler ultrasound was used to measure the peak systolic velocity (PSV), the end diastolic velocity (EDV), and the pulsatility index (PI) of clitoral arteries. Main Outcome MeasuresMicro-ultrastructure observation of clitoral tissue and color Doppler sonography of clitoral blood flow. ResultsOf the 38 women, 13 (68.4%) of group A and 15 (78.9%) of group B completed the study. Group A showed a mean PSV and EDV increase, and a mean PI decrease with respect to baseline (P < .001). Group B did not show any change in both the parameters (P = NS). By a quantitative study in both groups a variable degree of ultrastructural abnormalities of smooth muscle cells (SMCs) was observed, consisting in increased glycogen and lipoic deposits, cytoplasmic vacuoles, and focal increase of electron density of SMCs. Moreover, the mean SMC thickness of group A (1.83 ± 0.68 µm) was larger than that of group B (1.3 ± 0.41 µm) (P = .02). Clinical ImplicationsPDE5 inhibitors could be used to treat diabetic women with genital arousal disorder. Strengths & LimitationsThe study shows a clear effect of PDE5 inhibitors on clitoral SMCs. However, a limit was to not have investigated the sexual function/behavior of women of both groups, this was because of the short time of the study. ConclusionThis study could help to understand in what way PDE5 inhibitors act on the ultrastructural pathophysiological clitoral cavernous tissue of women with diabetes. It could support PDE5 inhibitor usage in women with genital sexual arousal disorder due to metabolic diseases.Caruso S, Cianci A, Cianci S, et al. Ultrastructural Study of Clitoral Cavernous Tissue and Clitoral Blood Flow From Type 1 Diabetic Premenopausal Women on Phosphodiesterase-5 Inhibitor. J Sex Med 2019;16:375–382.

Aβ immunotherapy for Alzheimer’s disease: effects on apoE and cerebral vasculopathy

Aβ immunotherapy for Alzheimer's disease (AD) results in the removal of Aβ plaques and increased cerebral amyloid angiopathy (CAA). In current clinical trials, amyloid-related imaging abnormalities (ARIAs), putatively due to exacerbation of CAA, are concerning side effects. We aimed to assess the role of the Aβ transporter apolipoprotein E (apoE) in the exacerbation of CAA and development of CAA-associated vasculopathy after Aβ immunotherapy. 12 Aβ42-immunized AD (iAD; AN1792, Elan Pharmaceuticals) cases were compared with 28 unimmunized AD (cAD) cases. Immunohistochemistry was quantified for Aβ42, apoE, apoE E4 and smooth muscle actin, and CAA-associated vasculopathy was analyzed. Aβ immunotherapy was associated with redistribution of apoE from cortical plaques to cerebral vessel walls, mirroring the altered distribution of Aβ42. Concentric vessel wall splitting was increased threefold in leptomeningeal vessels after immunotherapy (cAD 6.3 vs iAD 20.6%, P<0.001), but smooth muscle cell abnormalities did not differ. The findings suggest that apoE is involved in the removal of plaques and transport of Aβ to the cerebral vasculature induced by Aβ immunotherapy. Immunotherapy was not associated with CAA-related vascular smooth muscle damage, but was accompanied by increased splitting of the vessel wall, perhaps reflecting enhanced deposition and subsequent removal of Aβ. ARIA occurring in some current trials of Aβ immunotherapy may reflect an extreme form of these vascular changes.

High blood pressure arising from a defect in vascular function.

Hypertension, a major cardiovascular risk factor and cause of mortality worldwide, is thought to arise from primary renal abnormalities. However, the etiology of most cases of hypertension remains unexplained. Vascular tone, an important determinant of blood pressure, is regulated by nitric oxide, which causes vascular relaxation by increasing intracellular cGMP and activating cGMP-dependent protein kinase I (PKGI). Here we show that mice with a selective mutation in the N-terminal protein interaction domain of PKGIalpha display inherited vascular smooth muscle cell abnormalities of contraction, abnormal relaxation of large and resistance blood vessels, and increased systemic blood pressure. Renal function studies and responses to changes in dietary sodium in the PKGIalpha mutant mice are normal. These data reveal that PKGIalpha is required for normal VSMC physiology and support the idea that high blood pressure can arise from a primary abnormality of vascular smooth muscle cell contractile regulation, suggesting a new approach to the diagnosis and therapy of hypertension and cardiovascular diseases.

Gene Expression in Asthmatic Airway Smooth Muscle

Airway smooth muscle abnormalities are central to the pathophysiology of asthma. These airway smooth muscle cell abnormalities may include changes in cell number, size, phenotype, or function. Gene expression studies performed using asthmatic airway smooth muscle cells represent one approach to identifying the abnormalities of airway smooth muscle that occur in asthma in vivo. However, due to the technical challenges involved, only two studies have been performed to date using freshly obtained tissue from subjects with asthma. The first of these studies suggested increased expression of myosin light-chain kinase in airway smooth muscle from patients with asthma, whereas the second study found no difference in myosin light-chain kinase expression, nor any difference in other markers of smooth muscle phenotype in asthma. Studies performed in cell culture through the application of gene expression microarrays to profile airway smooth muscle cells exposed to potential mediators of asthma yield more consistent results, including induction by IL-13 of tenascin, the H1 histamine receptor, and IL-13 receptor subunits. However, the significance of these microarray findings for smooth muscle function is uncertain. Furthermore, gene expression studies have a fundamental limitation in that many functional properties of airway smooth muscle are regulated at other levels (e.g., protein phosphorylation). Thus, gene expression studies ultimately must be integrated with other methodological approaches to adequately study airway smooth muscle in asthma in vivo.

In Vivo Gastric and Intestinal Slow Waves in W/Wv Mice

The aim was to investigate whether there are regular gastric and intestinal slow waves in conscious W/WV mice. Eleven W/WV mice and 11 wild-type mice were implanted with two pairs of electrodes in the stomach and small intestine. Gastrointestinal slow waves were recorded both under anesthesia and in the conscious state. Atropine and verapamil were given separately to an additional 10 W/WV mice. Results were as follows. (1) The conscious W/WV mice showed lower rhythmic slow waves in the small intestine (77.1 vs 93.5%; P < 0.001). However, the frequency (10.7 vs 18.8 cpm; P < 0.0001) and the antregrade propagation of intestinal slow waves in W/Wv mice were significantly lower than in the controls. In the stomach, regular slow waves were recorded in both groups, with no difference between the two groups. (2) Anesthesia significantly impaired both gastric and intestinal slow waves in both groups. (3) Atropine and verapamil had no effects on the rhythmicity of intestinal slow waves. We conclude that ICC-MY may not be the sole pacemaker cells for slow waves in the small intestine. There may be some abnormality of smooth muscle cells in W/WV mice that causes a reduction in the frequency, rhythmicity, and antegrade propagation of slow waves.

Endothelial injury and dysfunction in ischemic acute renal failure

Ischemic acute renal failure is the most common cause of acute renal failure in hospitalized patients and has an average mortality rate of 50%. Although epithelial and vascular smooth muscle cell abnormalities have been clearly delineated in association with this condition, the extent of endothelial injury and dysfunction has been difficult to document, primarily for anatomic reasons. However, endothelial tight junction separation and endothelial cell detachment, blebbing, and necrosis have been observed after ischemia in other organs. In addition, adenosine triphosphate depletion studies in cultured endothelial cells have demonstrated that multiple actin-based alterations occur in a reversible and duration-dependent fashion. After an ischemic insult, total renal blood flow returns toward normal, but marked, regional alterations occur. Most affected is the outer medullary or corticomedullary junction region where blood flow remains approximately 10% of normal. In this area, the microvasculature becomes congested. Interstitial edema, red blood cell trapping, leukocyte adherence, and extravasation all contribute to this congestion. Increased expression of both P selectin and E selectin has been documented in renal endothelial cells after ischemic injury, and treatment with antibodies to either intercellular adhesion molecule-1, P selectins, or E selectins has been shown to minimize renal injury. During ischemia in vivo and adenosine triphosphate depletion in cell culture studies, F-actin destruction occurs, with polymerization leading to accumulation of intracellular actin aggregates. By using multiphoton microscopy, Voxx software, and the Tie-2 mouse with selective endothelial cell green fluorescent protein expression driven by the Tie-2 promoter, we have been able to identify macrovascular and microvascular endothelial cells in four dimensions (three dimensions plus time) intravitally. By using Texas red-labeled large molecular weight dextrans, we can document blood flow and vascular dysfunction. Intravital studies using multiphoton imaging techniques can now be conducted to identify and quantify endothelial cell injury and dysfunction in functioning organs.

Alterations in colonic smooth muscle function in cats with idiopathic megacolon

Abstract Objective To determine whether colonic smooth muscle dysfunction is involved in the pathogenesis of idiopathic megacolon in cats. Design In vitro smooth muscle mechanical measurements. Animals Colon from healthy cats and cats with idiopathic megacolon. Procedure Colonic smooth muscle strips were suspended in physiologic buffer solution, attached to isometric force transducers, and contracted with acetylcholine (ACh; 10−9 to 10−4M), substance P (SP; 10−10 to W−6M), cholecystokinin (CCK; 10−11 to 10−6M), potassium chloride (KCI; 10 to 80 mM), or electrical field stimulation (EFS; 25 V, 1 to 30 Hz, 0.5-millisecond duration). Isometric stress responses were compared with those obtained from healthy controls. Colonic smooth muscle strips were also evaluated histologically for neuronal and smooth muscle cell morphology. Results Passive isometric stress was not altered, but the active isometric stress responses of megacolon smooth muscle to ACh, SP, CCK, KCI, and EFS were significantly (P &lt; 0.05) diminished, compared with healthy controls. Differences were observed in longitudinal and circular smooth muscle from proximal and distal portions of the colon. Histologic evaluation revealed few abnormalities of smooth muscle cells or of myenteric or submucosal plexus neurons. The contractile response of megacolon smooth muscle to EFS, and the inhibition of this response by tetrodotoxin, suggest that myenteric and submucosal plexus neurons in megacolon smooth muscle are functional. Conclusions Idiopathic megacolon is a generalized dysfunction of colonic smooth muscle in cats. The diminished isometric stress responses to receptor occupancy (ACh, SP, and CCK) and membrane depolarization (KCI) further suggest that the disorder involves disturbance in the activation of smooth muscle myofilaments. (Am J Vet Res 1996;57:580-587)

Smooth Muscle Cell Abnormalities Associated with Gastric ECL Cell Carcinoids.

The histologic and immunohistochemical study of 45 ECL cell gastric carcinoids and of the extratumoral gastric mucosa revealed four variants of smooth muscle cell abnormalities: (1) hypertrophy of muscularis mucosae trapped within the tumors, a finding occurring in 76.5% of cases; (2) proliferation of stromal smooth muscle cells originating from the muscularas mucosae and mostly associated with tumor invasion of the submucosa (seen in 93.9% of cases with abundant stromal component of the tumors); (3) occurrence of frequent, prominent aggregates of smooth muscle cells in the lamina propria of the antral (but not of the fundic) mucosa of the stomach (found in 41.7% of cases); and (4) increased thickness of the extratumoral muscularis mucosae in the fundic (but not in the antral) mucosa of patients with gastric carcinoids. In addition, localized muscle cell proliferation was also associated with foci of micronodular hyperplasia of endocrine cells in the extratumoral mucosa. These findings were neither observed in control cases of gastric adenocarcinoma, gastric peptic ulcer, and duodenal peptic ulcer (10 unselected cases from each group) nor were they observed in 10 subjects with normal gastric mucosa collected at autopsy. With the possible exception of the increased thickness of the extratumoral fundic muscularis mucosae, which may be influenced by the mucosal inflammatory process, it is suggested that the present findings represent a proliferative response of smooth muscle cells to basic fibroblastic growth factor whose production by gastric carcinoids and their precursor lesions has recently been demonstrated.

Antroduodenojejunal Manometry in the Diagnosis of Chronic Idiopathic Intestinal Pseudoobstruction in Children

We analyzed the antroduodenojejunal (ADJ) manometric patterns in a group of 19 consecutive children (mean age, 53 months; range, 5 months to 14 years) referred for suspected chronic idiopathic intestinal pseu‐doobstruction. Diagnosis was based on typical symptoms, absence of extraintestinal diseases, and structural lesions of the gut at endoscopy and radiology. Surgical full‐thickness intestinal biopsies were evaluated in nine patients. Manometry of the stomach and small bowel was performed in the fasting and fed state with a multilumen perfused probe. All patients showed severe abnormalities of ADJ motor activity that were not seen in the eight controls (mean age, 38.2 months; range, 1–9 years). In 12 patients, manometric patterns suggesting neuropathic disease were detected with fasting and/or fed sustained and incoordinated duodenojejunal phasic waves, aberrant propagation and/or configuration of phase III of the inter‐digestive motility complex, inability of a meal to convert a fasting into a fed pattern, and prolonged groups of fasting and fed nonpropagated phasic waves. In seven of these patients, histology revealed marked changes of the intrinsic neurons. In four cases, manometry disclosed features suggestive of a myogenic disease, including severe fasting and fed infrequent low‐amplitude contractions, sometimes with some degree of propagation; in two of these cases, histology showed morphological abnormalities of smooth muscle cells of the gut wall. In three patients, manometry revealed signs suggestive of mechanical obstruction of the gut, such as repetitive post‐feeding clusters and simultaneous repeated broad‐based waves; in these patients, more detailed x‐ray studies showed organic obstructive causes (ileal lymphoma, Hirschsprung's disease, and intestinal malrotation). We conclude that, in children with symptoms suggesting chronic intestinal pseudoobstruction, manometry of the stomach and small bowel reveals severe gut dysmotility and can help establish the diagnosis and distinguish the underlying disease process.

Antroduodenojejunal manometry in the diagnosis of chronic idiopathic intestinal pseudoobstruction in children.

We analyzed the antroduodenojejunal (ADJ) manometric patterns in a group of 19 consecutive children (mean age, 53 months; range, 5 months to 14 years) referred for suspected chronic idiopathic intestinal pseudoobstruction. Diagnosis was based on typical symptoms, absence of extraintestinal diseases, and structural lesions of the gut at endoscopy and radiology. Surgical full-thickness intestinal biopsies were evaluated in nine patients. Manometry of the stomach and small bowel was performed in the fasting and fed state with a multilumen perfused probe. All patients showed severe abnormalities of ADJ motor activity that were not seen in the eight controls (mean age, 38.2 months; range, 1-9 years). In 12 patients, manometric patterns suggesting neuropathic disease were detected with fasting and/or fed sustained and incoordinated duodenojejunal phasic waves, aberrant propagation and/or configuration of phase III of the inter-digestive motility complex, inability of a meal to convert a fasting into a fed pattern, and prolonged groups of fasting and fed nonpropagated phasic waves. In seven of these patients, histology revealed marked changes of the intrinsic neurons. In four cases, manometry disclosed features suggestive of a myogenic disease, including severe fasting and fed infrequent low-amplitude contractions, sometimes with some degree of propagation; in two of these cases, histology showed morphological abnormalities of smooth muscle cells of the gut wall. In three patients, manometry revealed signs suggestive of mechanical obstruction of the gut, such as repetitive post-feeding clusters and simultaneous repeated broad-based waves; in these patients, more detailed x-ray studies showed organic obstructive causes (ileal lymphoma, Hirschsprung's disease, and intestinal malrotation).(ABSTRACT TRUNCATED AT 250 WORDS)

Infantile hypertrophic pyloric stenosis: myopathic type

Smooth muscle cell biopsies obtained at pyloromyotomy from 37 children with infantile hypertrophic pyloric stenosis (IHPS) were studied by light and electron microscopy and compared with 6 autopsy control cases without any clinical evidence of this disorder. In cases with IHPS an apparently irregular increase in the number of smooth muscle cells by mitosis was accompanied by an increase of the endoplasmic reticulum, proliferation of mitochondria and regressive changes, such as shrinkage, swelling, necrosis and apoptosis of smooth muscle cells. Other alterations, seen in some but not all cases consisted of large numbers of unusual dense granules some of which were clearly associated with actin filaments and, therefore, regarded as derivatives of the normally occurring dense bodies. Furthermore, intermyofibrillar and subsarcolemmal glycogen accumulations, various nuclear abnormalities and pleomorphic membranous cytoplasmic or nuclear bodies occurred. While smooth muscle cell abnormalities predominated in some cases of IHPS, in others there were more severe axonal changes in the myenteric plexus. It is suggested, therefore, that a primarily myogenic type of IHPS can be distinguished from a predominantly neurogenic type.