AB1438 CARDIOVASCULAR RISK STRATIFICATION FOR TOFACITINIB PATIENTS IN A LARGE TEACHING HOSPITAL

Background

Tofacitinib is an oral JAK-Inhibitor often reserved for patients with treatment-resistant Rheumatoid Arthritis and Psoriatic Arthritis. Tofacitinib modulates cytokines crucial to the inflammatory response which characterises the above conditions, and inhibits certain pathways in the inflammatory response cascade. Rheumatoid and Psoriatic Arthritis are linked with an inherent increased risk for major cardiovascular events. Recent emerging data has evidenced increased cardiovascular risk associated with long-term use of tofacitinib.

Objectives

To identify all patients currently undergoing Tofacitinib treatment across all sites at King’s College Hospital NHS Foundation Trust.​

To risk-stratify all patients into three categories; low risk of developing major cardiovascular events, moderate risk of developing MACE (patients with modifiable risk factors​, eg. high cholesterol or a borderline blood pressure), and high risk of developing MACE (unmodifiable risk factors​).

To switch patients at high risk onto another treatment or alternative JAK-inhibitor.​

Methods

Patient data was obtained through electronic patient records including age, blood pressure reading, full lipid profile, smoking status, and comorbidities (hypertension, diabetes, chronic kidney disease, previous cardiovascular history and history of malignancy). A QRISK3 score was calculated.

Modifiable risk factors with a lower QRISK3 score were categorised as moderate risk.

Patients were considered at high risk if they had a previous cardiovascular event, or a QRISK3 score of more than 10%.

Results

A total of 40 patients were on tofacitinib; 64% with RA, 31% with PsA, and 5% for other reasons (interstitial lung disease and colitis). Of the rheumatoid arthritis cohort: 36% of patients were at high risk, 40% at moderate risk, and 24% low risk. Of the psoriatic arthritis cohort: 67% at high risk, 25% at moderate risk, 8% at low risk.

Figure 1.

Conclusion

A significant number of patients were deemed at moderate and high risk. Patients with moderate risk were advised to undergo lifestyle changes, like exercise and diet modification and smoking cessation.

Patients at high risk were discussed at the trust-wide Rheumatology local clinical governance meeting, and advised to switch onto an alternative treatment or alternative JAK-inhibitor.

A repeat audit will be made in a few months’ time to assess the impact of lifestyle changes and alteration of drugs on cardiovascular risk.

References

[1]MHRA/CHM advice: Tofacitinib: new measures to minimise risk of major adverse cardiovascular events and malignancies (October 2021)

Disclosure of Interests

None declared

A207 COMMON BILE DUCT OBSTRUCTION FROM RADIOGRAPHICALLY OCCULT LITHIASIS: A CASE REPORT AND CAUTIONARY TALE

Background

Biliary obstruction from choledocholithiasis (CDL) can lead to many serious complications, such as cholangitis and pancreatitis. Among noninvasive diagnostic tests for CDL, MRCP is superior to US and CT with a sensitivity of 89–95%. Despite this, MRCP may not always identify the cause of obstruction, leading to diagnostic dilemmas.

Aims

We aim to review the various ways that CDL can hide on imaging, specifically MRCP.

Methods

A 22-year-old male with pyruvate kinase deficiency was admitted to General Surgery for acute cholecystitis, for which he had a laparoscopic cholecystectomy. Preoperative MRCP showed a 3 mm common bile duct (CBD) with no stones; however, gross inspection of the gallbladder showed multiple green stones. Around one month later, he was readmitted to General Surgery for symptomatic biliary obstruction, with total bilirubin 923, ALP 457 and ALT 559. He was not febrile and did not require antibiotics. An MRCP showed a CBD of 10 mm with intra- and extrahepatic biliary dilation, but no obstructing focus was seen. Gastroenterology was consulted for undifferentiated hyperbilirubinemia. After further discussion, an ERCP with sphincterotomy was done the next day which also did not show obstruction. An abdominal US done the day after ERCP showed improvement in biliary dilation. After ERCP, the patient’s symptoms improved. Total bilirubin, ALP, and ALT one month later decreased to 121, 134, and 139 respectively. The hypothesis was that he had an obstructing gallstone that camouflaged within bile on imaging.

Consent was obtained from the patient to present this case report.

Results

Although MRCP is one of the best noninvasive diagnostic tests for CDL, some stones may not appear on imaging. On MRCP, stones usually appear as hypointense spots surrounded by hyperintense bile on T2-weighted imaging. However, sludge can be isointense compared to bile. Additionally, stones impacted at the ampulla of Vater typically are not surrounded by bile and thus may evade detection on MRCP. Small stones <4 mm can be missed as well. CBD dilation greater than 10 mm is also associated with reduced sensitivity of MRCP for CDL. Even with ERCP, small stones may be missed unless seen on direct optical visualization after a blind balloon sweep.

Even if no obstructing lesion is seen on imaging, other clinical features can still suggest CDL requiring ERCP. The ASGE 2019 Guidelines on CDL recommend prompt ERCP for patients with total bilirubin >68.4 µmol/L and CBD dilation on imaging. Other radiographic signs suggesting CDL include CBD dilation, papillitis, and pericholecystic fat infiltration on CT, and MRCP findings of CDL-associated inflammation such as biliary wall thickening and periductal edema.

Conclusions

Even if MRCP does not show obvious obstruction, ERCP should still be considered if the likelihood of CDL remains high.

Funding Agencies

None

A225 INFERIOR VENA CAVA STENOSIS AFTER HEPATIC LOBECTOMY: A RARE CAUSE OF PORTAL HYPERTENSION AND REFRACTORY ASCITES

Background

Inferior vena cava (IVC) stenosis is a rare occurrence in post-liver transplant patients, affecting less than 3% of recipients. IVC stenosis is rarely described in non-transplant patients or considered in the differential of portal hypertension and refractory ascites. Patients with IVC stenosis may experience lower extremity edema, dyspnea, ascites and other signs of portal hypertension.

Aims

We describe a case of portal hypertension and refractory ascites secondary to IVC stenosis following hepatic lobectomy.

Methods

Case report.

Results

We report a 61-year-old woman with a history of diabetes, obesity status post sleeve gastrectomy and solitary neuroendocrine tumor of the right hepatic lobe, adjacent to the porta hepatis with no evidence of metastasis. She underwent a laparoscopic right hepatectomy with wedge resection (&lt;5 cm) in segment 4 to remove the neuroendocrine tumor in 2016. Surgery also included an intraoperative cholangiogram and placement of intra-ductal stent using endoscopic retrograde cholangiopancreatography (ERCP) technology as well as significant adhesiolysis along the IVC, right hepatic vein and biliary tract. In February 2020, the patient was referred to Hepatology for evaluation of new ascites. Imaging did not demonstrate evidence of tumor recurrence or features of cirrhosis but identified a new findings of portal hypertension and moderate ascites. Common causes of chronic liver disease were excluded and hepatic synthetic function was normal. Paracentesis revealed a high serum albumin ascites gradient (SAAG; 20 g/L) and a high ascitic fluid protein (34 g/L). Although these findings were suggestive of cardiac ascites, a 2D echocardiogram was normal. A trans-jugular liver biopsy was attempted in July 2020. The right atrial pressure was 8 mmHg and inferior vena cava (IVC) pressure was 22 mmHg at the level of the liver. Loss of pulsation suggested hemodynamically significant stenosis of the hepatic IVC. The wedged hepatic venous pressure was 3 mmHg and the calculated portal systemic gradient was 4 mmHg. A trans jugular biopsy failed due to unfavourable anatomy. These findings, taken in conjunction with previous results, suggested non-cirrhotic post-hepatic portal hypertension. Subsequent computed tomography imaging confirmed stenosis of the hepatic portion of the IVC and this was felt to be the ultimate cause of the portal hypertension. She has since been referred back to interventional radiology (IR) for consideration of balloon angioplasty dilation of the IVC stenosis as well as additional testing to determine if there is any underlying hepatic fibrosis related to congestive hepatopathy.

Conclusions

IVC stenosis post hepatic lobectomy is a rare phenomenon described in the literature but warrants high suspicion in cases of refractory ascites.

Funding Agencies

None

A211 SPONTANEOUS HBV REMISSION AFTER HBV REACTIVATION FOLLOWING TREATMENT WITH SOFOSBUVIR AND VELPATASVIR IN A PATIENT WITH HCV AND HBV CO-INFECTION: CASE REPORT

Background

In co-infected patients with hepatitis B (HBV) and hepatitis C (HCV), the treatment of HCV with direct-acting antiviral agents (DAA) can cause HBV reactivation. However, there are no clear guidelines on the timing of treatment initiation, especially in the absence of clinical signs of flare.

Aims

Here we discuss the case of a 34-year-old female with HBV and HCV genotype 3 who had HBV reactivation following HCV treatment, but did not require nucleos(t)ide therapy.

Methods

She initially presented with chronic inactive hepatitis B and chronic hepatitis C with HBV DNA level of 67.5 IU/mL and HCV RNA level of 3.33 x 106 IU/mL. She completed a 12 week course of sofosbuvir and velpatasvir for HCV and achieved sustained virologic remission, but subsequently developed reactivation of her HBV with HBV DNA peaking at 3.41 x 104 IU/mL twelve weeks post-treatment. She did not develop any signs of hepatitis and a decision was made to monitor her clinically.

Results

Two years later, she spontaneously went into remission with her HBV DNA levels being &lt;10 IU/mL.

Conclusions

The significance of this case is to illustrate HBV reactivation following treatment of HCV with DAAs may not necessitate immediate treatment, especially if there are no signs of flare. There have been similar reported cases, but larger prospective studies are required to determine the appropriate clinical context where monitoring may be acceptable instead of immediate treatment.

Funding Agencies

None

A227 UMBILICAL HERNIA INCARCERATION IN LIVER CIRRHOSIS: A RARE COMPLICATION OF PARACENTESIS

Background

Patients with decompensated liver cirrhosis with ascites frequently have umbilical hernias with a prevalence of 20% and are managed with large volume paracentesis (LVP). Common complications of LVP include hemorrhage, infection, and bowel perforation that occur infrequently with a frequency of less than 1%. However, incarceration of umbilical hernias has been reported as a rare complication of LVP and is speculated to be from ascitic fluid decompression that reduces the umbilical hernia ring diameter resulting in entrapment of the hernia sac. It is unclear whether the quantity or the fluid removal rate increases the herniation risk. Based on case series, this rare complication occurs within 48 hours of the LVP and requires emergent surgical repair and involves a high risk of morbidity and mortality due to potential infection, bleeding, and poor wound healing.

Aims

We describe a case report of an incarcerated umbilical hernia following a bedside large-volume paracentesis.

Methods

Case report

Results

A 59-year-old Caucasian male presented to the emergency department with a 24-hour history of acute abdominal pain following his outpatient LVP. His medical history included Child-Pugh class C alcoholic liver cirrhosis with refractory ascites managed with biweekly outpatient LVP and a reducible umbilical hernia. He reported the onset of his abdominal pain 2-hours after his LVP with an inability to reduce his umbilical hernia. Seven liters of clear, straw-coloured asitic fluid was drained. Laboratory values at presentation revealed a hemoglobin of 139 g/L, leukocyte count of 4.9 x109 /L, platelet count of 110 xo 109 /L, and a lactate of 2.7 mmol/L His physical exam demonstrated an irreducible 4 cm umbilical hernia and bulging flanks with a positive fluid wave test. Abdominal computed tomography showed a small bowel obstruction due to herniation of a proximal ileal loop into the anterior abdominal wall hernia, with afferent loop dilation measuring up to 3.4 cm. He was evaluated by the General Surgery consultation service and underwent an emergent laparoscopic hernia repair. There was 5 cm of small bowel noted to be ecchymotic but viable, with no devitalized tissue. He tolerated the surgical intervention with no post-operative complications and was discharged home.

Conclusions

Ultrasound-guided bedside paracentesis is a common procedure used in the management of refractory ascites and abdominal wall hernia incarceration should be recognized as a potential rare complication. To prevent hernia incarceration, patients with liver cirrhosis should be examined closely for hernias and an attempt should be made for external reduction prior to LVP. A high index of suspicion for this potential life-threatening condition should be had in patients who present with symptoms of bowel obstruction following a LVP.

Funding Agencies

None

The Development of Practice Recommendations for Drug-Disease Interactions by Literature Review and Expert Opinion

Background

Drug-disease interactions negatively affect the benefit/risk ratio of drugs for specific populations. In these conditions drugs should be avoided, adjusted, or accompanied by extra monitoring. The motivation for many drug-disease interactions in the Summary of Product Characteristics (SmPC) is sometimes insufficiently supported by (accessible) evidence. As a consequence the translation of SmPC to clinical practice may lead to non-specific recommendations. For the translation of this information to the real world, it is necessary to evaluate the available knowledge about drug-disease interactions, and to formulate specific recommendations for prescribers and pharmacists. The aim of this paper is to describe a standardized method how to develop practice recommendations for drug-disease interactions by literature review and expert opinion.

Methods

The development of recommendations for drug-disease interactions will follow a six-step plan involving a multidisciplinary expert panel (1). The scope of the drug-disease interaction will be specified by defining the disease and by describing relevant effects of this drug-disease interaction. Drugs possibly involved in this drug-disease interaction are selected by checking the official product information, literature, and expert opinion (2). Evidence will be collected from the official product information, guidelines, handbooks, and primary literature (3). Study characteristics and outcomes will be evaluated and presented in standardized reports, including preliminary conclusions on the clinical relevance and practice recommendations (4). The multidisciplinary expert panel will discuss the reports and will either adopt or adjust the conclusions (5). Practice recommendations will be integrated in clinical decision support systems and published (6). The results of the evaluated drug-disease interactions will remain up-to-date by screening new risk information, periodic literature review, and (re)assessments initiated by health care providers.

Actionable Recommendations

The practice recommendations will result in advices for specific DDSI. The content and considerations of these DDSIs will be published and implemented in all Clinical Decision Support Systems in the Netherlands.

Discussion

The recommendations result in professional guidance in the context of individual patient care. The professional will be supported in the decision making in concerning pharmacotherapy for the treatment of a medical problem, and the clinical risks of the proposed medication in combination with specific diseases.

A175 RECURRENT GASTROINTESTINAL BLEED – A LATE MANIFESTATION OF COLONIC TUBERCULOSIS TREATED CONSERVATIVELY

Background

The incidence of active tuberculosis (TB) in Canada is 4.8 per 100000 persons. Globally, gastrointestinal (GI) TB is rare and accounts for 5% of all extra-pulmonary cases. Clinical manifestations of intestinal TB include weight loss (75%), abdominal pain (54%), and changes in bowel habits (50%). GI bleeding has been observed in 5–15% of confirmed cases of colorectal TB. The cecum is the most common site of involvement, with the most common gross finding on colonoscopy being ulcerations (88%), and the least common being polypoid lesions (10%). Intestinal TB is treated the same as pulmonary TB, with endoscopic healing observed in the majority of cases following 9 months of anti-TB therapy. Surgery is entertained in cases of non-resolving obstruction, perforation, or fistula formation.

Aims

Management of stable, recurrent, large volume GI bleeding in TB colitis is not well established. We report such a case that resolved solely by anti-TB regimen.

Methods

Case report

Results

A 56 year old man with chronic kidney disease presented with cachexia and 40 pound weight loss over 6 months after return from India. He underwent computerized tomography scan of his chest, abdomen and pelvis. Multiple, large, cavitary lesions in the right upper lung lobe were seen, and confirmed to be TB by bronchoalveolar lavage. Abdominal imaging identified moderate circumferential wall thickening at the cecum concerning for intestinal TB. These findings were also retrospectively noted on a review of an abdominal MRI 4 months prior.

His course was complicated by episodes of large, alternating bright red blood per rectum and melena stools starting 5 days after initiation of anti-TB therapy. Colonoscopy revealed polypoid lesions in the cecum as well as blood throughout the colon, with no active source of bleeding. Surgery was considered for ongoing bleeding, however, because biopsies were negative for malignancy and positive on acid-fast stain, he continued conservative management with blood transfusions and anti-TB therapy. GI bleeding decreased significantly within the first 2 weeks, and resolved by day 25. He completed 1 year of anti-TB therapy, with no signs of colitis detected radiographically at the 6-month mark.

Conclusions

To our knowledge, this is the first report of GI bleeding as a very late manifestation of colonic TB, resolved with anti-TB therapy alone. Time from initial evidence of intestinal TB on imaging to the first bleed was 159 days, and time from initial symptoms was 6 months. As polypoid lesions are the least common gross finding on colonoscopy, a high degree of suspicion should be held in the right clinical setting. Surgical management should be considered only after conventional anti-TB therapy has failed.

Funding Agencies

None

A95 DO BENIGN LIVER TUMOURS ALWAYS STAY BENIGN? A CASE REPORT OF HEPATIC INFLAMMATORY PSEUDOTUMOR AND SUBSEQUENT CHOLANGIOCARCINOMA

Background

Hepatic inflammatory pseudotumors (HIPTs) are rare, benign lesions of unclear etiology which can be challenging to diagnose and differentiate from malignant processes. The optimal treatment and follow up of these lesions is controversial, and literature exists to support both surgical resection as well as conservative medical management. The natural history of HIPTs is generally benign, however there are some reports of disease recurrence, and two reports of malignant transformation to lymphoma.

Aims

To describe a case of HIPT with progression to malignancy.

Methods

Case report and review of the literature.

Results

A 53-year-old male presented to St. Joseph’s Healthcare Hamilton in August 2019 with a three-week history of abdominal pain and distention. He had a previous diagnosis of HIPT, incidentally found on ultrasound four years earlier. CT in January 2016 reported two well-marginated focal liver masses with peripheral rim enhancement and central hypodensity, 3.9 x 3.9cm in segment 2, and a 6 x 4.6cm central lesion, as well as diffuse fatty infiltration of the liver. Bloodwork showed a mildly elevated Ca19-9 626 kU/L, and normal CEA and AFP.

Two biopsies were performed in 2016, both demonstrating dense fibrous tissue and abundant chronic inflammatory cell infiltrate composed of lymphocytes, histiocytes, eosinophils, and plasma cells, with some areas of bland spindle cell proliferation. No malignant cells, and histology was felt to be consistent with HIPT.

MRI in September 2017 showed progression of disease, prompting Rheumatology to initiate immunosuppressive medications, however serial imaging continued to show increase in the size and number of lesions.

Upon presentation to hospital in August 2019 ultrasound showed new ascites, with ascitic fluid analysis reporting highly atypical cells with prominent nucleoli of uncertain origin. CT showed extensive intrahepatic lesions throughout both lobes of the liver, and tumor markers were elevated with Ca19-9 16,581 kU/L, CEA 10 ug/L, Ca125 511 kU/L, and normal AFP.

Repeat liver biopsy reported adenocarcinoma, likely cholangiocarcinoma, with background cirrhosis. Medical oncology did not feel he would tolerate chemotherapy, and he was thus discharged home with palliative supports.

Conclusions

HIPTs are benign lesions that are often initially misdiagnosed as malignancy, however this is the first case reporting progression of HIPT to cholangiocarcinoma. It is unclear if HIPT itself has premalignant potential, or whether its presence delays diagnosis of subsequent de novo malignancies. Given these uncertainties, as well as the lack of clarity on optimal management of HIPT, this case illustrates the importance of long-term clinical and radiographic follow up of these uncommon lesions, with consideration of repeat biopsy if the disease is not following the expected clinical course.

Funding Agencies

None

A199 BLACK ESOPHAGUS: AN UNDER-RECOGNIZED CAUSE OF UPPER GASTROINTESTINAL BLEEEDING

Background

“Black esophagus” is a term that refers to the endoscopic manifestation of acute esophageal necrosis (AEN), a rare but potentially under-recognized cause of upper gastrointestinal bleeding, characterized by the presence of strikingly black necrotic esophagus on upper endoscopy. The etiology is unclear although ischemic insults and caustic injury from gastric acid exposure are thought to play prominent roles. This condition is often seen in patients who are systemically unwell and have underlying comorbidities such as diabetes mellitus and vascular diseases.

Aims

We present a case of an elderly woman with diabetes and poor glycemic control who developed coffee ground emesis with her upper endoscopy revealing evidence of acute esophageal necrosis. AEN is an important diagnosis to consider in diabetic patients, as it generally carries a poor prognosis with mortality rates as high as 32% reported in the literature.

Methods

Case report and review of the literature

Results

A 61-year-old woman with medical history significant for poorly controlled insulin dependent diabetes (hemoglobin A1c, 11%) developed coffee ground emesis (confirmed via insertion of nasogastric tube) three days after initial admission to hospital for left tibial plateau fracture. Her bloodwork did not reveal any underlying diabetic ketoacidosis or hyperosomlar hyperglycemic state. Her esophagogastroduodenoscopy (EGD) showed black, necrotic-appearing discoloration of the esophageal mucosa circumferentially within the mid to distal part of the esophagus with a sharp transition point towards normal appearing mucosa at the gastroesophageal junction. Biopsies were deferred due to high risk of bleeding and perforation, and the previously placed nasogastric tube was not removed.

After endoscopy, conservative management was advised with restricted oral intake, intravenous proton pump inhibitor (PPI) inhibitor therapy for 72 hours and aggressive treatment of ongoing hyperglycemia. There were no signs or symptoms of esophageal rupture. The patient gradually recovered and in fact had her orthopedic surgery within a week of EGD. Furthermore, three days into the post operative period she developed venous thromboembolism and was placed on full dose oral anticoagulation and tolerated this without any further gastrointestinal bleeding.

Conclusions

AEN is an important diagnostic consideration in elderly diabetic patients presenting with acute upper gastrointestinal bleeding, particularly as timely recognition and management can significantly lower the unfavorable mortality associated with this condition.

Funding Agencies

None

Variability in Repeated Blood Pressure Measurements as a Marker of Frailty

OBJECTIVES

Variation in repeated blood pressure measurements may represent a decline in homeostatic mechanisms in blood pressure regulation in response to various internal or external stressors, indicating a frail state. We tested this hypothesis by examining the association between variability in repeated blood pressure measurements (BPV) and frailty status, adjusting for other confounding factors.

DESIGN

A longitudinal cohort study.

SETTING

Community centres in all three regions of Hong Kong.

PARTICIPANTS

1156 community-living older adults aged 60 years and over participated in a community geriatric screening program with blood pressure measurements three times a week over one year. Participants were divided into three groups based on variability of repeated blood pressure measurements (low, medium, high) using machine learning methods.

MEASUREMENTS

Frailty status was assessed using the FRAIL scale. Logistic regression was used to examine cross sectional association between frailty status and BPV adjusting for confounding factors, and also frailty transition with BPV.

RESULTS

In multi-variate models adjusting for co-variates, high BPV was associated with frailty (OR 1.57; 95% CI 1.05-2.37) among all participants; however, this was only significant in women in subgroup analysis. Similar findings were observed when transition to a more frail state was examined over a twelve month period.

CONCLUSIONS

The findings of this study support the concept of physiological dysregulation underlying the frail state, and that BPV calculated using machine learning methods may be used as a biomarker of such dysregulation.

Acute response to oral calcium loading in pregnant and lactating women with a low calcium intake: a pilot study

This pilot study in women from The Gambia with low habitual calcium intakes showed differences in calciotropic hormones between pregnant, lactating and non-pregnant, non-lactating women similar to those in Western women. The response to oral calcium loading indicates a high degree of calcium conservation independent of reproductive status.

INTRODUCTION

In pregnancy and early lactation, parathyroid hormone (PTH) concentrations may be suppressed. Uncertainty exists about how calcium metabolism is regulated, particularly when calcium intake is low.

METHODS

We investigated fasting markers of calcium metabolism and the acute calcemic and calciuric responses after an oral calcium load in 30 pregnant, lactating or non-pregnant, non-lactating (NPNL) Gambian women with low habitual calcium intakes. Women received 1 g elemental calcium (CaCO3) at 0 min. Blood was collected at -30 and 180 min. Urine was collected from -60 to 0, 0-120 and 120-240 min. Samples were analysed (blood: ionized calcium (iCa); plasma (p): total calcium (tCa), phosphate (P), creatinine (Cr), PTH, 1,25-dihydroxyvitamin D (1,25(OH)2D), osteocalcin (OC), β C-terminal cross-linked telopeptide of type 1 collagen (βCTX), cyclic adenosine monophosphate (cAMP); urine (u): Ca, P, Cr, cAMP).

RESULTS

Pre-loading, groups did not differ significantly in iCa, pP, uCa/Cr and uP/Cr. pOC concentrations were significantly lower and NcAMP and p1,25(OH)2D higher in pregnant women; pPTH and pβCTX in lactating women were higher than in NPNL women. Post-loading, iCa, ptCa and uCa/Cr concentrations increased; pPTH, NcAMP, βCTX and uP/Cr decreased in all groups, but the magnitude of change did not differ significantly between groups.

CONCLUSION

Differences between pregnant, lactating and NPNL Gambian women in pPTH, NcAMP and p1,25(OH)2D and bone markers were similar to Western women. However, the response to calcium loading indicates that there may be no differences in renal and intestinal calcium economy associated with reproductive status, potentially due to a high degree of calcium conservation associated with low intakes.

Isoform-specific proteolysis of apolipoprotein-E in the brain

Apolipoprotein-E (apoE) plays important roles in neurobiology and the apoE4 isoform increases risk for Alzheimer's disease (AD). ApoE peptides are biologically active and may be produced in the brain. It is unclear if apoE proteolysis is dependent on isoform or AD status and this was addressed here. Hippocampus, frontal cortex, occipital lobe and cerebellum samples were homogenized into fractions that were soluble in Tris-buffered saline (TBS), Triton X-100 or guanidine hydrochloride and analysed for apoE fragmentation by Western blotting. Approximately 20% of apoE3 was detected as fragments and this was predominantly as a 25 kDa peptide in TBS-soluble fractions. The concentration of TBS-soluble apoE fragments was two- to three-fold higher in apoE3 compared to apoE4 subjects. This difference was observed in all areas of the brain examined and was not related to AD status. Cathepsin-D treatment generated apoE fragments that were very similar to those detected in brain, however, no apoE isoform-specific differences in susceptibility to cathepsin-D proteolysis were detected. This indicates that proteolytic processing of apoE to form soluble fragments in the human brain is dependent on apoE isoform but not AD status.

Synergistic inhibition of vascular smooth muscle cell migration by phosphodiesterase 3 and phosphodiesterase 4 inhibitors

Cyclic nucleotide phosphodiesterases (PDEs) hydrolyze cAMP or cGMP and terminate their signaling. Two important families of PDEs that regulate cAMP signaling in cardiovascular tissues are the cGMP-inhibited PDEs (PDE3) and the cAMP-specific PDEs (PDE4). In this study, we have used a combination of an in vitro motility assay and a sensitive method for the measurement of cAMP in order to determine the relative roles of PDE3 and of PDE4 in the regulation of cAMP-mediated inhibition of VSMC migration. Our data demonstrate that forskolin, an activator of adenylyl cyclases, causes concentration-dependent inhibition of platelet-derived growth factor-induced VSMC migration. Incubation of cultured VSMCs with a PDE4-selective inhibitor, Ro 20-1724, markedly potentiated both the antimigratory effect and the increase in cAMP caused by forskolin. Cilostamide, a PDE3-selective compound, did not affect either the antimigratory activity of forskolin or its ability to increase cAMP. Cilostamide and Ro 20-1724 interacted synergistically to potentiate the inhibition of VSMC migration by forskolin and caused a supra-additive increase in cAMP. These data are consistent with an important role for both PDE3 and PDE4 in the regulation of cAMP-mediated inhibition of VSMC migration.