Identification of Novel and Known LDLR Variants Triggering Severe Familial Hypercholesterolemia in Saudi Families.

BACKGROUND: Familial hypercholesterolemia (FH) is a common illness mainly caused by variants occurring in the low-density lipoprotein receptor (LDLR) gene. FH is a leading cause of coronary artery disease. OBJECTIVE: This study aims to determine genetic defect(s) in homozygous and heterozygous FH index patients and their first-degree blood relatives and understand the genotype-phenotype correlation. METHODS: This study employed the genetic screening of FH-related genes by next-generation sequencing and cascade screening by capillary sequencing. RESULTS: We identified the presence of a novel frameshift variant [c.335_336insCGAG, p.(F114Rfs*17)] and three known missense variants [c.622G>A, p.(E208K)], [c.1474G>A, p.(D492N)], [c.1429G>A, p.(D477N)] in the LDLR gene of four unrelated Saudi families with FH. In proband 1, a nonsense variant c.1421C>G, p.(S474*) was also detected at exon 9 of the lipoprotein lipase gene. The segregation arrangement of the identified variants corresponded with the clinical characteristics. In this study, all the detected variants were confined in the ligand-binding domain and epidermal growth factor (EGF)-precursor homology domain of the LDLR protein, which portrayed severe clinical phenotypes of FH. Moreover, these LDLR variants were in a highly conserved residue of the proteins. CONCLUSION: In addition to the finding of the novel variant in the LDLR gene that extends the spectrum of variants causing FH, the results of this study also support the need for diagnostic screening and cascade genetic testing of this high-risk condition and to understand the genotype-phenotype correlation, which could lead to better prevention of coronary artery disease.

Prevalence of the Factor V Leiden Mutation Arg534Gln in Western Region of Saudi Arabia: Functional Alteration and Association Study With Different Populations.

The rare Gln534 (Factor V Leiden; FVL) allele (1:169,519,049 T>C) is associated with an increased risk of venous thrombosis. The purpose of this study was to measure the prevalence of Factor V Leiden mutation in thrombophilia patients with deep vein thrombosis. Also, we investigated the functional and structural characteristics of this mutation p.(Arg534Gln) to be examined the cumulative impact on venous thrombosis risk as well correlated with different populations by Genome Wide Association Studies (GWAS). A total of 108 patients with idiopathic deep vein thrombosis were examined for Factor V Leiden gene mutation. Our preliminary data show that about 10% of patients were detected with the heterozygous and homozygous form of the Factor V Leiden mutation. An association analysis confirmed that the Factor V SNP variant (rs6025) was highly associated (P-value 4.91 x10-^ -39) with an increased risk of venous thrombosis. Also, we found that the recognized SNP was important among HapMap populations. Our results indicated that among the 3 populations (Asian, African, and American) studied, this association was highest in the African population based on the r(2) significant threshold (P-value 5e-190). In addition, this mutation was located at the domain F5/8 type A 2, which can disturb this domain and abolish its function. Because of aspartic acid nearby wild type position as form in the salt bridge due to this discharge will disturb the ionic interaction made by the wild type residue Arg534. This residue was not found to be in contact with other domains of which the function was known. However, contact with other molecules or domains (THPH2: MIM: 188055) were still possible and might be affected by this mutation that may cause thrombophilia due to activated protein C resistance.

AML in Saudi Arabia: Analysis According to the European LeukaemiaNet 2017 Cytogenetic Classification.

INTRODUCTION: To the best of our knowledge, few studies have addressed the prognosis of patients with acute myeloid leukemia (AML) in Saudi Arabia. The present study retrospectively analyzed the prognostic factors in patients with de novo AML at a single institution owing to the observation of some differences with the reported data from the Western world. PATIENTS AND METHODS: Patients with de novo AML who had been referred to King Abdulla Medical City were included. All patients had undergone bone marrow aspiration, biopsy, flow cytometry, cytogenetics (conventional and fluorescence in situ hybridization panel performed at Mayo Clinic), molecular tests, and other routine tests. RESULTS: The data from 170 patients were reviewed. Of the 170 patients, 26 had had acute promyelocytic leukemia, 16 with AML had received less intensive therapy, 119 had received intensive induction, and 8 had refused treatment. The present analysis was limited to the 119 patients who had received intensive induction therapy. For the major cytogenetic categories, 17 of 27 patients with core binding factor leukemia (62.9%) were reassigned to the intermediate (n = 10; 37%) or unfavorable (n = 7; 25.9%) risk group according to the FLT3-ITD and NPM results. Of the 50 cases of normal cytogenetic findings, 2 (4%) were considered unfavorable, 12 (24%), favorable, 30 intermediate (60%), and 6 (12%) unknown. The median leukemia-free survival was 21.5 months. The median overall survival was 16.4 ± 2.2 months, with a 3-year survival rate of 37.2%. Multivariate Cox regression analysis revealed that the cytogenetics results (P = .002) and the presence of FLT-3 (P = .03) were independent prognostic factors for relapse-free survival. Performance status, response, relapse, and cytogenetics findings were independent prognostic factors for survival. CONCLUSIONS: The results from the present study revealed some differences in patient age and cytogenetic risk groups for patients with AML in our region and those in the Western world, including a younger median age, relevance of core binding factor leukemia, and a greater incidence of monosomies.

Identification of six novel factor viii gene variants using next generation sequencing and molecular dynamics simulation.

Hemophilia A is an X-linked recessive hemorrhagic disorder caused by variants in the F8 gene. To identify known and novel causative variants in hemophilia A, we have carried out genetic analysis among Saudi patients. Twenty-one patients, who were negative for inv-1/inv-22, were selected for analysis by next generation sequencing, thereafter confirmed by Sanger sequencing. In addition, the functionality and structural changes in the variant proteins were assessed using Molecular dynamics (MD) simulation and compared with wild-type and native proteins. In the samples we analyzed, we found 10 variants in 12 individuals; among them, five were novel and five were previously reported. The novel variants were located at positions: c.6130_6131insC, c.5815G>C, c.5493C>G, c.3734_3740delinsATTTCT and c.3744A>T. With the exception of one variant which was silent, the MD simulation revealed that the observed variants were causing severe structural changes when compared to the native protein and resulted in a loss of the protein's function. The MD analysis is in line with clinical data of patients who had <1% Factor VIII levels (severe hemophilia) with episodic bleeding, and were on more than one treatment. Moreover, some patients presented with chronic joint disability. These results will enrich the spectrum of variants and enlarge the factor VIII protein's database in the Saudi Arabian population.

The Dana Farber Consortium Protocol for the Treatment of Adolescents and Young Adults With Acute Lymphoblastic Leukemia: A Single Institution Experience in Saudi Arabia.

BACKGROUND: Recent retrospective analyses and phase II trials have shown differential outcomes in adolescents and young adults when treated with pediatric compared with adult protocols. The aim of this study was to evaluate the efficacy and toxicity of the Dana Farber Consortium Protocol (DFCP) in Saudi young adults diagnosed with de novo acute lymphoblastic leukemia (ALL). PATIENTS AND METHODS: In this retrospective study we included 38 patients with de novo ALL who presented to King Abdulla Medical City in the period from June 2010 to March 2015 and received the DFCP (Princess Margret modified version). RESULTS: A total of 38 patients were included with a median age of 19 years. Two patients died during induction treatment, and 35 of 38 patients achieved complete remission (92.1%). With a median follow-up period of 22 months, at 1 and 3 years, leukemia-free survival was 80% and 68%, respectively, and overall survival was 88% and 72%, respectively. Age younger than 21 years showed a significant association with longer survival. Toxicities included febrile neutropenia in all patients during induction, typhilitis in 8/38 (21%), pneumonia in 10/38 (26%), and pancreatitis in 5/38 patients (13%), 3/38 (7.8%) during induction and 2/38 (5.2%) during intensification. Osteonecrosis affected 3/38 patients (7.8%), and was detected during screening in 2/38 (5.2%) of these patients. There were no fractures or surgical interventions, and no venous thromboembolism was recorded. CONCLUSION: Although it might be feasible to use pediatric-inspired protocols in this age group, toxicity cannot be overlooked, and the application of these protocols might require modification of drug doses or schedules relative to those used for younger children. Moreover, additional surveillance and supportive measures should be implemented to maximize benefits while minimizing toxicity.

Clinical presentations and outcomes of influenza infection among hematology/oncology patients from a single cancer center: pandemic and post-pandemic seasons.

BACKGROUND: Influenza can cause severe infection in hematology/oncology patients. The occurrence of the 2009 pandemic represented an opportunity to study the impact of influenza on such patients in pandemic and post-pandemic seasons. METHODS: We retrospectively reviewed medical records of hematology/oncology patients who had laboratory-confirmed influenza infection during the 2009 pandemic and the first post-pandemic seasons. We assessed influenza-related outcomes in both seasons with emphasis on the development of pneumonia and mortality. We also analyzed factors associated with poor outcomes. RESULTS: We included 350 patients; 207 were diagnosed in the pandemic and 143 in the post-pandemic seasons. Influenza severity was similar in both seasons with no significant differences in the development of pneumonia or death. Infection with the pH1N1 virus was associated with the development of pneumonia (24.7% vs 14.9%, p = 0.029) but did not affect mortality. A multivariate analysis showed that initiation of antiviral treatment after > 48 h, healthcare acquisition of influenza, and low albumin were independent risk factors for the development of pneumonia (p values 0.022, 0.003, and < 0.0001, respectively). A log-rank test showed increased mortality in patients who received therapy > 48 h after onset of symptoms (p = 0.001). CONCLUSIONS: In hematology/oncology patients, influenza was as severe in the post-pandemic as in the pandemic season. Pneumonia developed more commonly in patients infected with pH1N1 virus. Healthcare acquisition of infection and low albumin were associated with the development of pneumonia. Delayed initiation of antiviral treatment was associated with both pneumonia and mortality.

Probability of finding an HLA-matched donor in immediate and extended families: the Jordanian experience.

Information regarding the probability of finding HLA-matched related donor for a patient awaiting hematopoietic stem cell transplantation (HSCT) in developing countries is scanty. We performed a retrospective review of HLA genotypes and related data for 1254 consecutive patients and their families at King Hussein Cancer Center in Amman, Jordan, between 2003 and 2011 to evaluate the chance of finding HLA-matched donor. The median family size was 5 for all patients in the study (range, 1-14), and the average number of donors was 1.4 ± 0.9 for pediatric patients and 1.6 ± 0.9 for adults. Overall, the probability of finding an HLA-matched related donor at our center was 65.5% (60.6% in pediatric patients and 74% in adults). Of the total identified donors, 18% were nonsibling donors after an immediate and/or extended family search in the pediatric group, and 6% were nonsibling donors in the adult group. Overall, 13% of donors were nonsibling donors. We conclude that the probability of finding a matched related donor for HSCT in Jordan is much higher than that reported in Western countries and Asia (65% versus 25%). We expect a similar trend in other developing and Arab countries. We recommend integrating an extended family search before or concomitantly with an unrelated donor search.

KRAS mutations and subtyping in colorectal cancer in Jordanian patients.

Colorectal cancer (CRC) is one of the most common malignancies in the Western world and Jordan. v-Ki-ras2 Kirsten rat sarcoma (KRAS) mutations represent an early event in the development and progression of CRC. Previous studies have demonstrated that KRAS mutations serve as a predictor of response to EGFR-targeted therapies for patients with metastatic CRC. The aim of this study was to determine the portion of CRC patients with wildtype KRAS status and molecular subtypes of KRAS mutations in Jordan as compared with other countries. DNA was isolated from 100 consecutive colorectal carcinoma specimens from patients who underwent surgical resection or colonoscopic biopsies of colorectal tumors and had developed metastatic disease. KRAS mutations were detected by hybridization-based strip assay as well as RT-PCR-based assay and confirmed by standard Sanger sequencing of codon 12 and 13 of exon 1 of the KRAS gene. Among 100 tested patients, 56% had a wt-KRAS genotype and 44% had a mutated KRAS genotype. The pGly12Asp was the most commonly detected mutation (54.5%). KRAS mutations were independently associated with patient age, gender and tumoral variables. The ratio of mutated versus wt-KRAS patients in this study is similar to those reported in Western countries but contrasts to neighboring Middle Eastern countries. Colorectal carcinoma cases from Jordan had higher KRAS mutation frequencies compared with other Middle Eastern countries which is likely to reflect different molecular pathogenesis and environmental exposures.

PPAR-α targeting in kidney fibrosis: is BAY PP1 just another renoprotector?

Interstitial fibrosis plays a major role in the progression of renal diseases. Peroxisome proliferator-activated receptor-α (PPAR-α) ligands are increasingly explored for their potential to reverse or halt tubulointerstitial fibrosis. This Commentary discusses new findings by Boor et al., who show that BAY PP1, a novel PPAR-α agonist, ameliorates renal fibrosis and dysfunction.

Endothelium-derived GM-CSF influences expression of oncostatin M.

During and after transendothelial migration, neutrophils undergo a number of phenotypic changes resulting from encounters with endothelium-derived factors. This report uses an in vitro model with human umbilical vein endothelial cells and isolated human neutrophils to examine the effects of two locally derived cytokines, granulocyte (G)-macrophage (M) colony-stimulating factor (GM-CSF) and G-CSF, on oncostatin M (OSM) expression. Neutrophils contacting activated HUVEC expressed and released increased amounts of oncostatin M (OSM), a proinflammatory cytokine known to induce polymorphonuclear neutrophil adhesion and chemotaxis. Neutrophil transendothelial migration resulted in threefold higher OSM expression and protein levels compared with nontransmigrated cells. Addition of anti-GM-CSF neutralizing antibody reduced OSM expression level but anti-G-CSF was without effect. GM-CSF but not G-CSF protein addition to cultures of isolated neutrophils resulted in a significant increase in OSM protein secretion. However, inhibition of ß(2) integrins by neutralizing antibody significantly reduced GM-CSF-induced OSM production indicating this phenomenon is adhesion dependent. Thus cytokine-stimulated endothelial cells can produce sufficient quantities of GM-CSF to influence in an adhesion-dependent manner, the phenotypic characteristics of neutrophils resulting in the latter's transmigration. Both transmigration and adhesion phenomenon lead to increased production of OSM by neutrophils that then play a major role in inflammatory response.

Early differential expression of oncostatin M in obstructive nephropathy.

Interstitial fibrosis plays a major role in progression of renal diseases. Oncostatin M (OSM) is a cytokine that regulates cell survival, differentiation, and proliferation. Renal tissue from patients with chronic obstructive nephropathy was examined for OSM expression. The elevated levels in diseased human kidneys suggested possible correlation between OSM level and kidney tissue fibrosis. Indeed, unilateral ureteral obstruction (UUO), a model of renal fibrosis, increased OSM and OSM receptor (OSM-R) expression in a time-dependent manner within hours following UUO. In vitro, OSM overexpression in tubular epithelial cells (TECs) resulted in epithelial-myofibroblast transdifferentiation. cDNA microarray technology identified up-regulated expression of immune modulators in obstructed compared with sham-operated kidneys. In vitro, OSM treatment up-regulated CC chemokine ligand CCL7, and CXC chemokine ligand (CXCL)-14 mRNA in kidney fibroblasts. In vivo, treatment of UUO mice with neutralizing anti-OSM antibody decreased renal chemokines expression. In conclusion, OSM is up-regulated in kidney tissue early after urinary obstruction. Therefore, OSM might play an important role in initiation of renal fibrogenesis, possibly by inducing myofibroblast transdifferentiation of TECs as well as leukocyte infiltration. This process may, in turn, contribute in part to progression of obstructive nephropathy and makes OSM a promising therapeutic target in renal fibrosis.

Stanniocalcin-1 regulates endothelial gene expression and modulates transendothelial migration of leukocytes.

The mammalian counterpart of the fish calcium-regulating hormone stanniocalcin-1 (STC1) inhibits monocyte chemotactic protein-1- and stromal-derived factor-1alpha (SDF-1alpha)-mediated chemotaxis and diminishes chemokinesis in macrophage-like RAW264.7 and U937 cells in a manner that may involve attenuation of the intracellular calcium signal. STC1 is strongly induced in the kidney following obstructive injury. We hypothesized that STC1 may serve to attenuate the influx of inflammatory cells to the site of tissue injury. In this study, we examined the effect of STC1 on the migration of freshly isolated human macrophages, neutrophils, and T and B lymphocytes through quiescent or IL-1beta-treated human umbilical vein endothelial cell (HUVEC) monolayers. STC1 inhibited transmigration of macrophages and T lymphocytes through quiescent or IL-1beta-activated HUVECs but did not attenuate the transmigration of neutrophils and B lymphocytes. STC1 regulates gene expression in cultured endothelial cells and is detected on the apical surface of endothelial cells in vivo. The data suggest that STC1 plays a critical role in transendothelial migration of inflammatory cells and is involved in the regulation of numerous aspects of endothelial function.

Angiogenesis-like activity of endothelial cells co-cultured with VEGF-producing smooth muscle cells.

A number of strategies have been investigated to improve therapeutic vascularization of ischemic and bioengineered tissues. In these studies, we genetically modified vascular smooth muscle cells (VSMC) to promote endothelial cell proliferation, migration, and formation of microvascular networks. VSMCs were virally transduced to produce vascular endothelial growth factor (VEGF), which acts as a chemoattractant and mitogen of endothelial cells (EC). VSMCs transduced with VEGF(165) cDNA produced significant levels of the protein (2-4 ng/10(5) cell/day). The proliferation of ECs increased after exposure to VEGF-transfected SMCs or their conditioned media. The chemotactic response of ECs to the VEGF-producing cells was explored in two in vitro systems, the modified Boyden chamber assay and a 2-D fence-style migration assay, and both demonstrated increased migration of ECs in response to VEGF-transfected cells. Furthermore, endothelial cells seeded on top of the VEGF-transfected SMCs formed capillary-like structures. These results suggest that VSMCs genetically modified to produce VEGF could be a potential delivery mechanism to enhance endothelial cell migration and subsequent capillary formation, which in turn could improve vascularization of ischemic or regenerating tissue. Furthermore, this system could potentially be used as an in vitro test bed for evaluation of novel angiogenic and anti-angiogenic compounds.

Tissue engineered small-diameter vascular grafts.

Arterial occlusive disease remains the leading cause of death in western countries and often requires vascular reconstructive surgery. The limited supply of suitable small-diameter vascular grafts has led to the development of tissue engineered blood vessel substitutes. Many different approaches have been examined, including natural scaffolds containing one or more ECM proteins and degradable polymeric scaffolds. For optimal graft development, many efforts have modified the culture environment to enhance ECM synthesis and organization using bioreactors under physiologic conditions and biochemical supplements. In the past couple of decades, a great deal of progress on TEVGs has been made. Many challenges remain and are being addressed, particularly with regard to the prevention of thrombosis and the improvement of graft mechanical properties. To develop a patent TEVG that grossly resembles native tissue, required culture times in most studies exceed 8 weeks. Even with further advances in the field, TEVGs will likely not be used in emergency situations because of the time necessary to allow for cell expansion, ECM production and organization, and attainment of desired mechanical strength. Furthermore, TEVGs will probably require the use of autologous tissue to prevent an immunogenic response, unless advances in immune acceptance render allogenic and xenogenic tissue use feasible. TEVGs have not yet been subjected to clinical trials, which will determine the efficacy of such grafts in the long term. Finally, off-the-shelf availability and cost will become the biggest hurdles in the development of a feasible TEVG product. Although many obstacles exist in the effort to develop a small-diameter TEVG, the potential benefits of such an achievement are exciting. In the near future, a nonthrombogenic TEVG with sufficient mechanical strength may be developed for clinical trials. Such a graft will have the minimum characteristics of biological tissue necessary to remain patent over a period comparable to current vein graft therapies. As science and technology advance, TEVGs may evolve into complex blood vessel substitutes. TEVGs may become living grafts, capable of growing, remodeling, and responding to mechanical and biochemical stimuli in the surrounding environment. These blood vessel substitutes will closely resemble native vessels in almost every way, including structure, composition, mechanical properties, and function. They will possess vasoactive properties and be able to dilate and constrict in response to stimuli. Close mimicry of native blood vessels may aid in the engineering of other tissues dependent upon vasculature to sustain function. With further understanding of the factors involved in cardiovascular development and function combined with the foundation of knowledge already in place, the development of TEVGs should one day lead to improved quality of life for those with vascular disease and other life-threatening conditions.

Enhancing mechanical properties of tissue-engineered constructs via lysyl oxidase crosslinking activity.

A number of strategies have been investigated to enhance the mechanical stability of engineered tissues. In this study, we utilized lysyl oxidase (LO) to enzymatically crosslink extracellular matrix (ECM) proteins, particularly collagen and elastin, to enhance the mechanical integrity of the ECM and thereby impart mechanical strength to the engineered tissue. Vascular smooth muscle cells (VSMCs) were liposomally transfected with the LO gene. Both Northern and Western analyses confirmed increased LO expression. Increased LO activity was demonstrated using a fluorescent enzyme substrate assay and by observation of the presence of increased levels of desmosine, a product of LO crosslinking, in the ECM. The mechanical effects of altered crosslink densities within tissue-engineered constructs were demonstrated in a VSMC-populated collagen gel model. When smooth muscle cells transfected with lysyl oxidase were seeded in collagen gels, the tensile strength and elastic modulus in these constructs increased by approximately two-fold compared to constructs seeded with mock-transfected VSMCs. Also, desmosine levels in the LO-populated collagen gels were higher than they were in mock-seeded gels, as demonstrated via immunohistochemical staining. Compositional analysis of the ECM deposited by the transformed cells showed similar collagen and elastin levels, and cell proliferation rates were similar as well, thus attributing increased mechanical properties to ECM crosslinking.