Associations Between Patterns of Esophageal Dysmotility and Extra-Intestinal Features in Patients With Systemic Sclerosis.

OBJECTIVE: The gastrointestinal tract is commonly involved in patients with systemic sclerosis (SSc) with varied manifestations. As our understanding of SSc gastrointestinal disease pathogenesis and risk stratification is limited, we sought to investigate whether patterns of esophageal dysfunction associate with specific clinical phenotypes in SSc. METHODS: Patients enrolled in the Johns Hopkins Scleroderma Center Research Registry who completed high-resolution esophageal manometry (HREM) studies as part of their clinical care between 2011 and 2020 were identified. Associations between esophageal abnormalities on HREM (absent contractility [AC], ineffective esophageal motility [IEM], hypotensive lower esophageal sphincter [hypoLES]) and patient demographic information, clinical characteristics, and autoantibody profiles were examined. RESULTS: Ninety-five patients with SSc had HREM data. Sixty-five patients (68.4%) had AC (37 patients with only AC, 28 patients with AC and a hypoLES), 9 patients (9.5%) had IEM, and 11 patients (11.6%) had normal studies. AC was significantly associated with diffuse cutaneous disease (38.5% versus 10.0%; P < 0.01), more severe Raynaud's phenomenon, including digital pits, ulcers, or gangrene (56.9% versus 30.0%; P = 0.02), and reduced median diffusing capacity of lung for carbon monoxide (50.6% versus 72.2%; P = 0.03). AC was observed in most of the patients who died (13 of 14; P = 0.06). These findings were not seen in patients with IEM. CONCLUSION: Among patients with SSc, AC is associated with a significantly more severe clinical phenotype. IEM may associate with a milder phenotype. Further studies are needed to evaluate AC, IEM, and their clinical impact relative to the timing of other end-organ complications in SSc.

Relationship Between Gastrointestinal Transit, Medsger Gastrointestinal Severity, and University of California-Los Angeles Scleroderma Clinical Trial Consortium Gastrointestinal Tract 2.0 Symptoms in Patients With Systemic Sclerosis.

OBJECTIVE: Systemic sclerosis (SSc)-associated gastrointestinal (GI) complications are attributed to a variety of factors, including diet, microbiota dysbiosis, or GI transit abnormalities. Our objective was to examine the contribution of abnormal GI transit to SSc Medsger GI severity scores and/or University of California Los Angeles Scleroderma Clinical Trial Consortium Gastrointestinal Tract (UCLA GIT) 2.0 symptoms. METHODS: Patients with SSc and GI symptoms (n = 71) and healthy controls (n = 18) underwent whole gut transit (WGT) scintigraphy to assess transit from the esophagus to the colon. The presence of delayed transit and percent emptying in each GI region were measured. We compared the WGT measurements between categories of the Medsger GI severity score (0-4) and across UCLA GIT 2.0 domains and total score (0-3). RESULTS: A total of 88% of patients had >1 abnormal region of the gut on WGT scintigraphy. All patients requiring total parenteral nutrition had delayed small bowel transit, compared to only approximately 11% of patients in other Medsger GI severity groups (P ≤ 0.01). Severe colonic transit delays were more likely in patients with Medsger GI scores of 3 (pseudo-obstruction and/or malabsorption) compared to other Medsger GI groups (P = 0.02). Seventy-percent of these patients had ≤30% colonic emptying at 72 hours. Modest associations were noted between gastroesophageal reflux disease symptoms and delayed esophageal (r = -0.31, P = 0.05) and gastric emptying (r = -0.32, P = 0.05). CONCLUSION: These data are important in providing evidence that SSc bowel disease affects transit of GI content and that delay in transit accounts in part for both bowel symptoms and Medsger GI severity. Prospective studies examining the benefit of early therapeutic intervention targeting GI transit abnormalities in patients at high risk for severe GI complications are needed.

Sphingosine-1-phosphate receptor 1 reporter mice reveal receptor activation sites in vivo.

Activation of the GPCR sphingosine-1-phosphate receptor 1 (S1P1) by sphingosine-1-phosphate (S1P) regulates key physiological processes. S1P1 activation also has been implicated in pathologic processes, including autoimmunity and inflammation; however, the in vivo sites of S1P1 activation under normal and disease conditions are unclear. Here, we describe the development of a mouse model that allows in vivo evaluation of S1P1 activation. These mice, known as S1P1 GFP signaling mice, produce a S1P1 fusion protein containing a transcription factor linked by a protease cleavage site at the C terminus as well as a ß-arrestin/protease fusion protein. Activated S1P1 recruits the ß-arrestin/protease, resulting in the release of the transcription factor, which stimulates the expression of a GFP reporter gene. Under normal conditions, S1P1 was activated in endothelial cells of lymphoid tissues and in cells in the marginal zone of the spleen, while administration of an S1P1 agonist promoted S1P1 activation in endothelial cells and hepatocytes. In S1P1 GFP signaling mice, LPS-mediated systemic inflammation activated S1P1 in endothelial cells and hepatocytes via hematopoietically derived S1P. These data demonstrate that S1P1 GFP signaling mice can be used to evaluate S1P1 activation and S1P1-active compounds in vivo. Furthermore, this strategy could be potentially applied to any GPCR to identify sites of receptor activation during normal physiology and disease.

Histone acetyl transferases CBP and p300 are necessary for maintenance of renin cell identity and transformation of smooth muscle cells to the renin phenotype.

In response to a homeostatic threat circulating renin increases by increasing the number of cells expressing renin by dedifferentiation and re-expression of renin in arteriolar smooth muscle cells (aSMCs) that descended from cells that expressed renin in early life. However, the mechanisms that govern the maintenance and reacquisition of the renin phenotype are not well understood. The cAMP pathway is important for renin synthesis and release: the transcriptional effects are mediated by binding of cAMP responsive element binding protein with its co-activators, CBP and p300, to the cAMP response element in the renin promoter. We have shown previously that mice with conditional deletion of CBP and p300 (cKO) in renin cells had severely reduced renin expression in adult life. In this study we investigated when the loss of renin-expressing cells in the cKO occurred and found that the loss of renin expression becomes evident after differentiation of the kidney is completed during postnatal life. To determine whether CBP/p300 is necessary for re-expression of renin we subjected cKO mice to low sodium diet + captopril to induce retransformation of aSMCs to the renin phenotype. The cKO mice did not increase circulating renin, their renin mRNA and protein expression were greatly diminished compared with controls, and only a few aSMCs re-expressed renin. These studies underline the crucial importance of the CREB/CBP/p300 complex for the ability of renin cells to retain their cellular memory and regain renin expression, a fundamental survival mechanism, in response to a threat to homeostasis.