Ajonuma L C

Ajonuma L C
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Ajonuma L C
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Publications Authored By Ajonuma L C

2010Dec
East Afr J Public Health
East Afr J Public Health 2010 Dec;7(4):286-8
Department of Internal Medicine, De La Salle University Medical Center, DasmariƱas, Cavite, Philippines.

The quality of life (QOL) of hemodialysis patients is often compromised and many tools have been developed to assess the health-related QOL of chronic kidney disease (CKD) patients undergoing hemodialysis. However, no such tool is currently in use in the Philippines. The objective of this study is to determine if Nottingham Health Profile (NHP) can be a useful tool in the Philippines.Read More

Eighty patients undergoing hemodialysis in the dialysis unit of our hospital were enrolled for this study. Sixty-nine patients completed the study. Comparative analysis revealed significant difference in social isolation with favorable result for the Filipino patients. Other measures correlate well although with differences that were not statistically significant. NHP can be successfully applied as a standard QOL tool in the Philippines. However, it should be translated into Filipino to avoid language difficulty. NHP may be recommended for QOL determination in other developing countries.

2010Nov
Int J Adolesc Med Health
Int J Adolesc Med Health 2010 Apr-Jun;22(2):213-7
Oral Biosciences, Faculty of Dentistry, The University of Hong Kong, Prince Philips Dental Hospital, Hong Kong, SAR. Louisca@alumni.cuhk.net

Periodontal diseases are among the most common human infections that not only impact oral health but also are associated with adverse systemic diseases such as cardiovascular diseases, stroke, diabetes, and respiratory diseases. Periodontal diseases is a chronic severe inflammatory process of the gingiva leading to the destruction of tooth-supporting structures, alveolar bone, and subsequently tooth loss due to bacteria infection. While it has been reported that several oral biofilm-forming bacteria might be involved, the role of C.Read More

pneumoniae infection in the pathogenesis of periodontal disease remains unknown. The present hypothesis proposes that C. pneumoniae is involved in the pathogenesis of periodontal diseases. This will lead to a better understanding of the etiopathogenesis of periodontal disease, better treatment strategy and savings on total health care costs.

2010Jun
Cell Biol. Int.
Cell Biol Int 2010 Jun 20;34(6):593-600. Epub 2010 Apr 20.
Epithelial Cell Biology Research Center, Department of Physiology, The Chinese University of Hong Kong, Shatin, NT, Hong Kong SAR, People's Republic of China.

Chlamydia trachomatis is an obligate intracellular Gram-negative pathogen affecting over 600 million people worldwide with 92 million new cases occurring globally each year. C. trachomatis enter the cells and replicate to infect different tissues/organs, giving rise to a spectrum of pathological conditions; however, the exact mechanism or receptor(s) for their entry is not well understood.Read More

Here we report that CFTR (cystic fibrosis transmembrane conductance regulator), an apical epithelial anion channel, is required for cellular entry and internalization of C. trachomatis. Human epithelial cell lines expressing functional CFTR internalized more C. trachomatis than the cells expressing mutant Delta508 CFTR. The in vitro cellular uptake of C. trachomatis can be blocked by CFTR inhibitors or antibody, and the in vivo cellular uptake of C. trachomatis in CFTR mutant (CFTR(-/-)) mice was significantly less compared with that in the wild-type. Direct interaction between CFTR and C. trachomatis LPS (lipopolysaccharide) is demonstrated by their immune-co-localization and co-immunoprecipitation. Despite an increase in CFTR expression observed upon C. trachomatis LPS challenge, a reduction in its ion channel activity is observed, consistent with the notion that CFTR functions as a receptor for cellular entry and internationization of C. trachomatis, with compromised ion-channel function. These findings, for the first time, demonstrate that CFTR functions as a cell-surface receptor for epithelial cell entry, and internalization of C. trachomatis and these findings may lead to the development of new treatment strategies to curtail the spread of chlamydial infections.

2010May
Fertil. Steril.
Fertil Steril 2010 May 15;93(8):2608-14. Epub 2010 Mar 15.
Epithelial Cell Biology Research Center, Key Laboratory for Regenerative Medicine of Ministry of Education of China, School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, NT, Hong Kong, People's Republic of China.

To investigate whether abnormal expression of cystic fibrosis transmembrane conductance regulator (CFTR), a cyclic adenosine 3':5' monophosphate (cAMP)-activated chloride channel, and uterine fluid accumulation upon Chlamydia trachomatis infection may result in implantation failure, thus contributing to C. trachomatis-induced female infertility.
Experimental animal study.Read More


University laboratory animal service center.
Adult female mice with regular estrous cycles.
Intrauterine injection of C. trachomatis lipopolysaccharide (LPS), tumor necrosis factor-alpha (TNF-alpha), and estrogen (E) at diestrus and preimplantation.
The CFTR messenger RNA (mRNA) and protein levels were evaluated by reverse transcriptase-polymerase chain reaction (RT-PCR) and Western blot, respectively, in mouse uterus treated with C. trachomatis LPS, TNF-alpha or E. Endometrial electrolyte transport and uterine fluid accumulation were determined by the short circuit current and uterine wet weight, respectively. Number of implanted embryos was also counted to demonstrate the effect of treatments.
Uterine C. trachomatis LPS infection induced up-regulation of CFTR expression with enhanced anion secretion, abnormal fluid accumulation in mouse uterus at diestrus, and reduced implantation rate. Administration of exogenous TNF-alpha to mouse uterus mimicked the C. trachomatis LPS infection-induced CFTR up-regulation, enhanced CFTR channel activity, and fluid accumulation. Abnormal uterine fluid accumulation and implantation failure were also observed when CFTR was up-regulated by E.
The present results suggest that C. trachomatis infection-induced release of cytokines could abnormally up-regulate CFTR expression leading to abnormal uterine fluid accumulation, which may result in infertility often associated with C. trachomatis infection.

Genital Chlamydia (C) trachomatis infection has been recognized as the single most common cause of pelvic inflammatory disease leading to severe tubal damage, ectopic pregnancy, infertility and hydrosalpinx. However, the mechanism underlying the formation of hydrosalpinx induced by C. trachomatis infection remains largely unknown.Read More

We performed this study to determine the involvement of cystic fibrosis transmembrane conductance regulator (CFTR), a cAMP-activated chloride channel that regulates epithelial electrolyte and fluid secretion, in hydrosalpinx fluid formation.
Western blot analysis was used to determine CFTR expression in the hydrosalpinges that were seen on the ultrasound scans of infertile assisted reproduction treatment patients. Correlation with C. trachomatis infection was done by testing patients' sera for C. trachomatis immunoglobulin G antibody titer using a Capita enzyme-linked immunosorbent assay based kit. CFTR involvement was further verified in a rat C. trachomatis infection model and confirmed using CFTR mutant (CFTR(tm1Unc)) mice.
Here we report on the up-regulated expression of CFTR in the hydrosalpinx tissues of infertile patients with detectable serum levels of C. trachomatis antibody (immunoglobulin G). In a rat model, increased CFTR expression and fluid accumulation could be observed in the uterine horns infected with C. trachomatis elementary bodies, which was reversed by antibiotics treatment. In C. trachomatis-infected CFTR(tm1Unc) mice, however, no detectable fluid accumulation was observed.
These findings suggest the involvement of CFTR in the pathogenesis of hydrosalpinx fluid formation and may provide grounds for a better treatment strategy to improve assisted reproduction treatment outcome in infertile patients with hydrosalpinx.

2008Jul
Cell Biol. Int.
Cell Biol Int 2008 Jul 29;32(7):801-6. Epub 2008 Mar 29.
Epithelial Cell Biology Research Center, Li Ka Shing Institute of Health Science, Department of Physiology, The Chinese University of Hong Kong, Shatin, NT, Hong Kong.

Abnormal fluid accumulation in tissues, including the life-threatening cerebral and pulmonary edema, is a severe consequence of bacteria infection. Chlamydia (C.) trachomatis is an obligate intracellular gram-negative human pathogen responsible for a spectrum of diseases, causing tissue fluid accumulation and edema in various organs.Read More

However, the underlying mechanism for tissue fluid secretion induced by C. trachomatis and most of other infectious pathogens is not known. Here, we report that in mice C. trachomatis infection models, the expression of cystic fibrosis transmembrane conductance regulator (CFTR), a cAMP activated chloride channel, is up regulated together with increased cytokine release and tissue fluid accumulation that can be reversed by treatment with antibiotic specific for C. trachomatis and CFTR channel blocker. However, C. trachomatis infection cannot induce tissue edema in CFTRtm1Unc mutant mice. Administration of exogenous IL-1beta to mice mimics the C. trachomatis infection-induced CFTR upregulation, enhanced CFTR channel activity and fluid accumulation, further confirming the involvement of CFTR in infection-induced tissue fluid secretion.

2008May
Med. Hypotheses
Med Hypotheses 2008 27;70(6):1174-8. Epub 2007 Dec 27.
St. Mary's Maternity Hospital, Amakohia, Ihitte, Etiti, Imo State, Nigeria. louisca@alumni.cuhk.net

Ovarian hyperstimulation syndrome (OHSS) remains one of the most life-threatening and potentially fatal complications of assisted reproduction treatments (ART), due to excessive stimulation of the ovaries by exogenously administrated gonadotropins. The pathogenesis of OHSS remains obscure and patient treatments are empirical. However, vascular endothelial growth factor (VEGF) has been suggested to be responsible for OHSS.Read More

The present hypothesis aims to discuss the possible role of epithelial ion channels particularly cystic fibrosis transmembrane conductance regulator (CFTR) involvement in the pathogenesis of OHSS. This may provide grounds for the development of a better treatment strategy to reduce the risk of OHSS and improve in vitro fertilization (IVF) outcome.

2007Aug
Sheng Li Xue Bao
Sheng Li Xue Bao 2007 Aug;59(4):495-504
Epithelial Cell Biology Research Center, Department of Physiology, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China. hsiaocchan@cuhk.edu.hk

An optimal fluid microenvironment in the female reproductive tract is considered to be crucial for successful reproductive events. Fluid absorption and secretion across the reproductive tract epithelia largely depends on electrolyte transport through the apically and basolaterally located ion channels, working together with an array of other transporters. This review will discuss the role of epithelial sodium channel (ENaC) and the cystic fibrosis transmembrane conductance regulator (CFTR) in regulating the fluid volume and composition of the reproductive tract and their importance in various reproductive events such as sperm capacitation and implantation.Read More

Disturbance of the fluid microenvironment due to defects or abnormal regulation of these ion channels as causes for a number of pathological conditions, such as ovarian hyperstimulation syndromes, hydrosalpinx and infertility, is also discussed.

2005Dec
Mol. Endocrinol.
Mol Endocrinol 2005 Dec 28;19(12):3038-44. Epub 2005 Jul 28.
Epithelial Cell Biology Research Center, Department of Physiology, Faculty of Medicine, Chinese University of Hong Kong, Shatin, New Territory, Hong Kong.

Ovarian hyperstimulation syndrome (OHSS) remains one of the most life-threatening and potentially fatal complications of assisted reproduction treatments, arising from excessive stimulation of the ovaries by exogenous gonadotropins administrated during in vitro fertilization procedures, which is characterized by massive fluid shift and accumulation in the peritoneal cavity and other organs, including the lungs and the reproductive tract. The pathogenesis of OHSS remains obscure, and no definitive treatments are currently available. Using RT-PCR, Western blot, and electrophysiological techniques we show that cystic fibrosis transmembrane conductance regulator (CFTR), a cAMP-activated chloride channel expressed in many epithelia, is involved in the pathogenesis of OHSS.Read More

Upon ovarian hyperstimulation, rats develop OHSS symptoms, with up-regulated CFTR expression and enhanced CFTR channel activity, which can also be mimicked by administration of estrogen, but not progesterone, alone in ovariectomized rats. Administration of progesterone that suppresses CFTR expression or antiserum against CFTR to OHSS animals results in alleviation of the symptoms. Furthermore, ovarian hyperstimulation does not induce detectable OHSS symptoms in CFTR mutant mice. These findings confirm a critical role of CFTR in the pathogenesis of OHSS and may provide grounds for better assisted reproduction treatment strategy to reduce the risk of OHSS and improve in vitro fertilization outcome.

2005Oct
Cell Biol. Int.
Cell Biol Int 2005 Oct;29(10):849-56
Department of Physiology, Faculty of Medicine, Epithelial Cell Biology Research Center, The Chinese University of Hong Kong, Hong Kong.

Hydrosalpinx (HSP) has been shown to be detrimental to the outcome of assisted reproduction, but little is known of its pathology. This prospective study examined and detailed ultrastructural characterization of HSP of infertile women presenting for assisted reproductive treatments. Both light and electron microscopies were used to characterize HSP.Read More

Hematoxylin and eosin staining of HSP showed areas without epithelial cell lining or with abnormalities such as flattening of the epithelial layer and exfoliation of epithelial cells with occasional normal columnar epithelial lining. HSP muscle fibers were atrophic and occasionally replaced by fibrous tissues, or separated by areas of severe edema. Inflammatory cells could be found in hydrosalpinx fluid (HF) in the lumen in areas with flattened to no epithelial cells, without epithelial lining, as well as in dilated blood vessels and/or lymph vessels. Scanning electron microscopy of the epithelial surface revealed epithelial denudation-severe loss of both cilia and microvilli and stomata exuding globular bodies on eroded ampulla surfaces. Severe chronic inflammation and damage to the epithelial lining and musculature of Fallopian tubes and the presence of inflammatory cells provides an explanation for HF formation, and thus for the detrimental effects of HF on reproductive processes and IVF outcome.

2005Sep
Cell Biol. Int.
Cell Biol Int 2005 Sep;29(9):785-91
Epithelial Cell Biology Research Center, Department of Physiology, The Chinese University of Hong Kong, Shatin, NT, Hong Kong Special Administrative Region, PR China.

Nitric oxide (NO), which is produced from l-arginine by three isoforms of NO synthase (NOS), has been implicated in reproductive functions. However, the specific role of NOS isoforms in gamete function and fertilization is not clear. Three types of NOS knockout mice were super ovulated and fertilized in vitro and in vivo.Read More

The sperm count and motility, in vivo and in vitro fertilization rate as indicated by two-cell embryos and blastocyst rate were examined. The sperm count and motility from all three knockout mice were not significantly different from that of the wild type. Inducible NOS (iNOS) knockout mice were found to have the largest number of two-cell embryos/mouse collected after fertilization in vivo (P<0.01), but the rate of blastocyst formation from two-cell embryos in vitro was similar for all three knockouts. The rate of in vitro fertilization using either iNOS-deficient sperm or oocytes, but not those deficient in the other two NOS isoforms, was significantly elevated when compared to that in the wild type (P<0.001). While all three types of NOS do not seem to play a significant role in pre-ejaculated sperm function, iNOS may play an inhibitory role in sperm and oocyte functions affecting the process of fertilization and early embryo development.

2005May
Hum. Reprod.
Hum Reprod 2005 May 10;20(5):1228-34. Epub 2005 Feb 10.
Epithelial Cell Biology Research Center, Department of Physiology, Faculty of Medicine, Chinese University of Hong Kong, Shatin.

Hydrosalpinx (HSP), characterized by abnormal fluid accumulation in the Fallopian tube, is one of the main causes of infertility in women; however, the mechanism underlying the formation of hydrosalpinx fluid (HF) remains elusive. The present study investigated the possible involvement of cystic fibrosis transmembrane conductance regulator (CFTR), a cAMP-dependent chloride channel, in the pathogenesis of hydrosalpinx.
Masson's trichrome staining was used to characterize epithelial transformation in human HSP; RT-PCR, immunohistochemistry and immunofluorescence staining were used for CFTR expression and localization.Read More


Masson's trichrome staining showed areas of epithelial transformation, focally attenuated and pseudostratified. Immunostaining showed enhanced CFTR immunoreactivity in the focally attenuated and pseudostratified areas of HSP epithelium. RT-PCR revealed that CFTR expression in HSP was significantly greater than that in normal Fallopian tubes.
These results indicate that HSP epithelium undergoes epithelial transformation with elevated CFTR expression, which may lead to increased transepithelial electrolyte and fluid secretion resulting in HF formation. The present findings may lead to the development of new treatment strategies for infertile patients with HSP.

2004Jun
Cell Biol. Int.
Cell Biol Int 2004 ;28(6):433-9
Epithelial Cell Biology Research Center, Department of Physiology, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, NT, Hong Kong SAR.

Interaction between the cystic fibrosis transmembrane conductance regulator (CFTR), a CAMP-activated Cl- channel, and epithelial Na+ channel (ENaC) has been proposed as the major mechanism regulating uterine fluid absorption and secretion. Differential expression of these ion channels may give rise to dynamic changes in the fluid environment affecting various reproductive events in the female reproductive tract. This study investigated the expression and localization of CFTR and ENaC during the pre-implantation period.Read More

Semi-quantitative reverse transcriptase polymerase chain reaction and immunohistochemistry were used to study the expression and localization of CFTR and ENaC in uteri collected from mature superovulated female mice. RT-PCR showed maximal ENaC and CFTR expression on day 3 after mating. Maximal immunoreactivity was also observed for both ENaC and CFTR on day 3 after mating. However, ENaC was immunolocalized to the apical membrane of both luminal and glandular epithelia, while CFTR was predominantly found in the stromal cells rather than the epithelial cells. Differential expression and localization of CFTR and ENaC provide a molecular mechanism by which maximal fluid absorption can be achieved immediately prior to implantation, to ensure the immobilization of the blastocyst necessary for implantation.

2003Oct
Nat. Cell Biol.
Nat Cell Biol 2003 Oct 28;5(10):902-6. Epub 2003 Sep 28.
Epithelial Cell Biology Research Center, Department of Physiology, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong, China.

Cystic fibrosis transmembrane conductance regulator (CFTR) is a cAMP-activated chloride channel expressed in a wide variety of epithelial cells, mutations of which are responsible for the hallmark defective chloride secretion observed in cystic fibrosis (CF). Although CFTR has been implicated in bicarbonate secretion, its ability to directly mediate bicarbonate secretion of any physiological significance has not been shown. We demonstrate here that endometrial epithelial cells possess a CFTR-mediated bicarbonate transport mechanism.Read More

Co-culture of sperm with endometrial cells treated with antisense oligonucleotide against CFTR, or with bicarbonate secretion-defective CF epithelial cells, resulted in lower sperm capacitation and egg-fertilizing ability. These results are consistent with a critical role of CFTR in controlling uterine bicarbonate secretion and the fertilizing capacity of sperm, providing a link between defective CFTR and lower female fertility in CF.

2003Jul
Cell Biol. Int.
Cell Biol Int 2003 ;27(7):543-8
Epithelial Cell Biology Research Center, Department of Physiology, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, NT, HKSAR, Hong Kong.

Our previous studies have observed an effect of Matrigel, a solubilized basement membrane preparation extracted from the Engelbreth-Holm-Swarm (EHS) mouse sarcoma, on the expression of ion channels in mouse endometrial epithelia; namely the cystic fibrosis transmembrane conductance regulator (CFTR), a cAMP-dependent Cl(-)channel, and the epithelial sodium channel (ENaC). The present study further investigated the effects of Matrigel and its individual components on the functional expression of CFTR and ENaC using the short-circuit current (Isc) technique. The results showed that different components of Matrigel, namely growth factors, laminin and collagen, had differential effects on the functional activity of the two ion channels in murine endometrial epithelium.Read More

The information obtained may be useful for designing future in vitro culture models to investigate the functional roles of these ion channels in the endometrium.

Recent studies have reported the negative impact of hydrosalpinx on IVF outcome. Toxic effects of hydrosalpinx fluid (HF) have been the main reason for the recommendation of functional surgery, salpingectomy, prior to IVF. The present study characterized hydrosalpinx epithelial cell culture and examined the effects of its conditioned medium (CM) on sperm motility, acrosome reaction and embryo development.Read More


Normal Fallopian tubes (n = 6) and hydrosalpinges (n = 9) were used to prepare epithelial cell culture and CM. Epithelial cell characterization was confirmed using electron microscopy. Sperm motility and acrosome reaction were determined using computer-aided sperm analysis and acrobead assay respectively and embryo development by mouse embryo development assay.
The percentage of human motile sperm incubated in hydrosalpinx CM was significantly different from those in normal Fallopian tube (NFT) CM and modified human tubal fluid medium (hTF) (control) (P < 0.05 at 3 h and P < 0.001 at 5 and 24 h), with alteration in movement characteristic, linearity, 24 h after incubation in hydrosalpinx CM (P < 0.05). However, other sperm movement characteristics remained unchanged. Reduced acrosome reaction and poor mouse embryo development were also observed in hydrosalpinx CM but not in NFT CM and hTF.
The results suggest that hydrosalpinx epithelial cells may be producing a fluid milieu hostile to sperm and early embryo development. The established epithelial cell culture system may provide a model to further investigate the mechanisms underlying the toxic effects of HF on embryo development and the adverse effects on IVF outcomes.

2002Jun
Hum. Reprod. Update
Hum Reprod Update 2002 May-Jun;8(3):255-64
Epithelial Cell Biology Research Center, Department of Physiology, Faculty of Medicine, The Chinese University of Hong Kong, NT, Hong Kong SAR.

The adverse effects of hydrosalpinx on the outcome of IVF have been well documented; however, the causes for impaired implantation in patients with hydrosalpinx are poorly understood. Hydrosalpinx fluid has been shown to be toxic to mouse embryos but not human embryos, and this has become a topic of intense debate. An understanding of the mechanisms underlying hydrosalpinx formation following pelvic inflammatory disease appears to be essential in elucidating the causes for reduced implantation in hydrosalpinx patients and providing more rational treatments.Read More

This review discusses the mechanisms underlying hydrosalpinx formation and its adverse effect on IVF outcome, with new insights into possible involvement of Fallopian tube epithelial transporters and ion channels, particularly the cystic fibrosis transmembrane conductance regulator (CFTR). Possible links between Chlamydia trachomatis in pelvic inflammatory disease and the subsequent CFTR-mediated events in hydrosalpinx formation leading to infertility in hydrosalpinx are proposed. The causes of reduced implantation, particularly in patients with visible hydrosalpinges shown on ultrasound scanning, are re-examined in light of these possible mechanisms.

2000Apr
Hum. Reprod.
Hum Reprod 2000 Apr;15(4):772-7
Department of Obstetrics and Gynaecology, Queen Mary Hospital, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region, People's Republic of China.

The negative impact of hydrosalpinx on IVF outcome is well recognized but some reports indicate that tubal infertility with hydrosalpinx is a heterogeneous entity and may have different effects on the outcome. The embryotoxic effects of hydrosalpinx fluid (HF) have been documented in mouse but not human embryos. This study examined the effects of HF on sperm motility and survival after various periods of incubation.Read More

Fifteen infertile patients with hydrosalpinx shown on ultrasound monitoring during ovarian stimulation underwent aspiration of HF after egg collection. Electrolytes, glucose and pyruvate concentrations were within the physiological ranges found in normal human tubal fluid. Sperm motility and velocities remained unchanged after 5 h of incubation with various concentrations of HF but the percentage of motile spermatozoa was significantly reduced after 24 h of incubation. Both 50 and 100% HF were potentially cytotoxic (survival indices <85%). The detrimental effect seemed to be dependent on the concentrations of HF. Low osmolarity, low lactate concentrations or the protein content may be responsible for the loss of sperm motility. A human sperm survival test using HF may be useful in selecting appropriate treatment options for patients with hydrosalpinx undergoing IVF treatment or tubal surgery.