Indispensable value of clinical trials in the modernization of traditional Chinese medicine: 12 years' experience at CUHK and future perspectives

New Emerging Aspect of Herbal Extracts for the Treatment of Osteoporosis: Overview

As the global population ages, osteoporosis is becoming a more common silent disease. Osteoporosis is characterized by decreased bone quality and strength, which increases the risk of fragility fractures in the elderly. According to estimates, 50% of women eventually suffer from an osteoporotic fracture. Due to increasing disability, more frequent hospital hospitalizations, and most critically, fragility fractures have been linked to a reduced quality of life. Osteoporotic fractures have been linked to an increased mortality risk; and must be considered in awareness as a serious health concern. There are anti-osteoporotic medications available that improve bone quality. Considering the availability of various treatment options, still there are a lot of underserved needs in the treatment of fractures and osteoporosis. For example, the application of natural products and herbal resources for fracture healing, because of the androgen-like and antioxidant characteristics of the plants, they can play a crucial for accelerating the repair of bone fractures. In this article, we'll discuss the herbal remedies that are essential for treating osteoporosis (bone disease).

Effects of a Chlorogenic Acid-Containing Herbal Medicine (LASNB) on Colon Cancer

Background

Plant polyphenols, which contain phenolic acids such as chlorogenic acid (CGA), can be used for the treatment of gastrointestinal cancer and have gained increasing attention in recent years. In this study, we explored a novel CGA-containing herbal medicine named LAS^NB, which was extracted from Lonicera japonica Thunb., Agrimonia eupatoria L., and Scutellaria barbata D.Don.

Methods

CGA in LAS^NB was analyzed using high-performance liquid chromatography (HPLC). The biological functions and molecular mechanisms of LAS^NB were investigated in colon cancer cell lines (HCT116, HCT15, and CT26), a normal colon cell line (NCM460), and a CT26 xenograft model. To assess safety, hematological toxicity and pathology of the liver, kidney, and lung were evaluated.

Results

LAS^NB suppressed HCT116, HCT15, and CT26 colon cancer progression by inhibiting proliferation capacity, promoting cell apoptosis, and suppressing cell migration both in vitro and in vivo. Investigation into the underlying molecular mechanism indicated that LAS^NB suppressed the activation of receptor tyrosine kinase- (RTK-) MEK-ERK and NF-κB pathways. With regard to safety, slight interstitial vascular congestion in the lung was observed, but no severe pathological or hematological toxicity was detected.

Conclusions

We found that LAS^NB suppressed the progression of colon cancer via the RTK-MEK-ERK and NF-κB pathways, with no severe toxicity observed. Therefore, LAS^NB has the potential to be used as a supplementary herbal medicine for the treatment of colon cancer.

Jia-Wei-Yu-Ping-Feng-San Attenuates Group 2 Innate Lymphoid Cell-Mediated Airway Inflammation in Allergic Asthma

The incidence of asthma has increased in recent decades. Although corticosteroids and bronchodilators are used in clinical practice, the control of asthma remains a challenge. Allergic asthma is characterized airway inflammation mediated by type 2 immune response. Group 2 innate lymphoid cells (ILC2s) are an important source of type 2 cytokines IL-5 and IL-13, which contribute to the progress of asthma. Jia-Wei-Yu-Ping-Feng-San (JWYPFS), a traditional Chinese medicine, has been widely used to treat asthma in China. In this study we investigated the mechanisms of JWYPFS in the treatment of asthma, especially the effect on ILC2s important in airway inflammation. Female C57BL/6 mice were sensitized and challenged with OVA to establish a model of allergic asthma. Airway hyperresponsiveness was examined by direct airway resistance analysis. Inflammatory cell counts were determined in bronchoalveolar lavage fluid (BALF). Inflammatory cell infiltration and mucus hypersecretion in lung tissue sections was observed by HE and PAS staining, respectively. The numbers and proportions of ILC2s as well as the ILC2s-related transcription factors GATA3, IRF4, and type 2 cytokines were measured in lung tissue samples. Additionally, ILC2s were collected from mouse lung; ILC2s-related cytokines and GATA3 and IRF4 were evaluated after IL-33-induced activation of ILC2s in vitro. Elevated inflammatory cells, mucus secretion, airway hyperresponsiveness and type 2 cytokines in the OVA-treated asthma group indicated that an allergic asthma model had been established. JWYPFS treatment attenuated airway resistance and reduced inflammatory cells including eosinophils, and inhibited mucus production and type 2 cytokines in these asthmatic mice. Moreover, JWYPFS treatment dramatically decreased the numbers and proportions of ILC2s and the mRNA levels of GATA3 and IRF4. In an in vitro experiment JWYPFS significantly suppressed GATA3, IRF4 and type 2 cytokine expression, including IL-5 and IL-13 in IL-33-stimulated ILC2s. JWYPFS alleviates ILC2s-mediated airway inflammation, suggesting that JWYPFS might be an effective agent to treat allergic asthma.

Impact of TCM on Tumor-Infiltrating Myeloid Precursors in the Tumor Microenvironment

The tumor microenvironment (TME) is composed of tumor cells, blood/lymphatic vessels, the tumor stroma, and tumor-infiltrating myeloid precursors (TIMPs) as a sophisticated pathological system to provide the survival environment for tumor cells and facilitate tumor metastasis. In TME, TIMPs, mainly including tumor-associated macrophage (TAM), tumor-associated dendritic cells (DCs), and myeloid-derived suppressor cells (MDSCs), play important roles in repressing the antitumor activity of T cell or other immune cells. Therefore, targeting those cells would be one novel efficient method to retard cancer progression. Numerous studies have shown that traditional Chinese medicine (TCM) has made extensive research in tumor immunotherapy. In the review, we demonstrate that Chinese herbal medicine (CHM) and its components induce tumor cell apoptosis, directly inhibiting tumor growth and invasion. Further, we discuss that TCM regulates TME to promote effective antitumor immune response, downregulates the numbers and function of TAMs/MDSCs, and enhances the antigen presentation ability of mature DCs. We also review the therapeutic effects of TCM herbs and their ingredients on TIMPs in TME and systemically analyze the regulatory mechanisms of TCM on those cells to have a deeper understanding of TCM in tumor immunotherapy. Those investigations on TCM may provide novel ideas for cancer treatment.

Effects of a Matrine- and Sophoridine-Containing Herbal Compound Medicine (AH-05) on Liver Cancer

Herbal medicine can present an alternative way of treating liver cancer. Here, we explored a matrine- and sophoridine-containing herbal compound medicine (AH-05) extracted from Adenophora capillaris, Sophora flavescens, Astragalus, and other plants. H22 and HepG2 cell models, as well as an H22 xenograft model, were established. Cell proliferation and apoptosis were measured in vitro, and tumor volume and weight were observed in vivo. The activation of AKT/mTOR and nuclear factor-κB (NF-κB) pathways in tumor cells and the polarization of CD4/CD8 T cells in the spleen were tested. To assess safety, hematological toxicity and pathology of the liver, kidney, spleen, and intestine were evaluated. AH-05 inhibited cell viability in a dose- and time-dependent manner. In vivo, tumor volume and weight were reduced, and the activation of NF-κB p50, NF-κB p65, AKT, p-AKT Ser473, and mTOR was suppressed. In addition, AH-05 promoted CD4+ T cell polarization in the spleen. With regard to safety, slight intestinal mucosa edema was observed, but no severe pathological or hematological toxicity was detected. AH-05 exhibited its therapeutic effects against liver cancer by regulating the AKT/mTOR and NF-κB signaling pathways, and the immune environment, by promoting CD4+ T cell polarization in the spleen. Thus, AH-05 represents a potential supplementary herbal compound medicine for liver cancer.

Study on the Anticancer Effect of an Astragaloside- and Chlorogenic Acid-Containing Herbal Medicine (RLT-03) in Breast Cancer

Background

Although surgery, chemotherapy, radiotherapy, and endocrine therapy are widely used in clinical practice for breast cancer treatment, herbal medicines (HMs) are considered as an alternative to palliative treatments because of their coordinated intervention effects and relatively low side effects. Astragaloside (AS) and chlorogenic acid (CGA) are major active ingredients of Radix Astragali and Lonicera japonica, which have shown antitumorigenic properties in certain cancers, but the role of HMs containing both AS and CGA remains unclear in breast cancer. In this study, we explored an AS- and CGA-containing HM (RLT-03) extracted from Radix Astragali, Lonicerae Japonicae Flos, Trichosanthin, and Rhizoma imperatae.

Methods

RLT-03 was extracted using water and n-butanol, and the AS and CGA ingredients in RLT-03 were identified by high-performance liquid chromatography (HPLC) and evaporative light-scattering detector (ELSD). 4T1, EMT6, BT-549, and MDA-MB-231 breast cancer cell lines were used, and an EMT6 xenograft model was established. Cell proliferation, migration, and apoptosis were measured in vitro, and tumor volume and weight were observed in vivo. The expression of VEGF, EGF, IL-10, TGF-β, and CD34 and cell apoptosis in tumors were examined.

Results

RLT-03 inhibited cell viability and induced apoptosis in a dose- and time-dependent manner. In vivo, tumor volume and weight were reduced, and the expression of VEGF, EGF, IL-10, TGF-β, and CD34 was suppressed in the tumor microenvironment, while cell apoptosis was induced.

Conclusion

RLT-03 exhibited therapeutic effects against breast cancer by regulating the expression of ligands of receptor tyrosine kinases (RTKs) and inflammatory factors. Thus, RLT-03 represents a potential supplementary HM that can be used in breast cancer therapy.

Meta-Analysis of Xihuang Pill Efficacy When Combined with Chemotherapy for Treatment of Breast Cancer

Objective

To systematically evaluate the efficacy of Xihuang pill (XHP) in breast cancer patients receiving chemotherapy.

Methods

Three English and four Chinese databases were searched. Literature was screened using EndNote X7 and data were analyzed by Review Manager.

Results

This review included 13 randomized clinical studies of 1272 patients. The results showed that XHP increased the tumor response [risk ratio (RR) = 2.91; 95% confidence interval (CI): 1.98-4.26] and improved Karnofsky performance score (KPS) for breast cancer patients receiving chemotherapy [RR = 4.96; 95% CI = 2.07-11.86]. In addition, XHP treatment significantly reduced chemotherapy-induced adverse events, including nausea and vomiting [RR = 0.50; 95% CI = 0.33-0.74], WBC reduction [RR = 0.71; 95% CI = 0.47-1.06], platelet reduction [RR = 0.53; 95% CI = 0.19-1.44], hemoglobin reduction [RR = 0.31; 95% CI = 0.19-0.52], and hepatic function damage [RR = 0.63; 95% CI = 0.35-1.11].

Conclusion

XHP combined with chemotherapy in comparison with chemotherapy alone could significantly enhance the tumor response, improve KPS, and alleviate toxicity induced by chemotherapy in breast cancer patients.

Tetrahydroxy stilbene glucoside protected against diabetes-induced osteoporosis in mice with streptozotocin-induced hyperglycemia

Tetrahydroxy stilbene glucoside (TSG), an active component from medicinal herb Polygonum multiflorum Thunb, could block the activity of the tissue renin-angiotensin system (RAS), which plays a critical role in development of diabetic osteoporosis. This study aimed to determine if TSG therapy could alleviate bone deteriorations in diabetic mouse model induced by streptozotocin. The diabetic mice showed the loss of trabecular bone mass and the changes of trabecular bone microarchitectural parameters as well as the increase in amount of tartrate-resistant acid phosphatase (TRAP)-positive osteoclasts at the distal metaphysis of femur when compared with those of nondiabetic mice. Treatment with TSG significantly elevated calcium content in serum and bone and improved biological parameters of trabecular bone, accompanied by increasing messenger RNA (mRNA) expression of RUNX-2, COL-I, and OCN and protein expression of β-catenin as well as down-regulating protein expression of RAS components including renin and AT1R. In addition, TSG repressed diabetes-induced decrease in ratio of OPG/RANKL expression and increase in sclerostin expression in bone. The similar effects of TSG on osteoblasts-specific genes were found in MC3T3-E1 cells. Taken together, the present study demonstrated the osteopreserve effects of TSG in diabetic mice, and the underlying mechanism might be attributed to its regulation on osteogenesis and osteoclastogenesis.

The Antitumor and Immunomodulatory Effect of Yanghe Decoction in Breast Cancer Is Related to the Modulation of the JAK/STAT Signaling Pathway

Background

Yanghe decoction (YHD) has been used in the treatment of breast cancer for hundreds of years in Asia. However, the underlying mechanisms are currently unknown. The present study aims to evaluate the efficacy of YHD on antitumor and immune system enhancement in a 4T1 mouse breast cancer model and to clarify the antitumor mechanisms of YHD in breast cancer.

Materials and Methods

The YHD was orally administrated for 2 weeks after inoculation. Tumor tissues were then removed, weighed, and homogenized. Flow cytometry was used to detect the number of Myeloid-Derived Suppressor Cells (MDSCs), Natural Killer T Cells (NKTs), and T cell subsets. Quantitative real-time PCR was used to detect the expression of inducible nitric oxide synthase (iNOS) and arginase-1 (ARG-1). Western blot was used to detect the protein expression of signal transducers and the activator of transcription 1 (STAT1), phosphorylated-signal transducers and the activator of transcription 1 (p-STAT1), signal transducers and the activator of transcription 3 (STAT3), and phosphorylated-signal transducers and the activator of transcription 3 (p-STAT3). The expression levels of interleukin-6 (IL-6), transforming growth factor-β (TGF-β), and interferon-γ (IFN-γ) were detected using an enzyme linked immunosorbent assay.

Results

We found that the tumor weight of YHD high-dose group was significantly lower compared with the control group (p<0.05). The YHD depressed the expression of MDSCs, iNOS, ARG-1, IL-6, TGF-β, and p-STAT3 and significantly increased the expression of IFN-γ, NKTs, CD4⁺ T cells, and p-STAT1.

Conclusion

Our results showed that The mechanisms of YHD inhibit 4T1 breast tumor growth may be related to downregulating the expression of iNOS and ARG-1, negatively regulating the Janus kinase/STAT3 (JAK/STAT3) pathway by repressing the expression of IL-6 and TGF-β. Meanwhile, YHD enhances the immune capacity via increasing the expression of NKTs, CD4⁺ T cells, IFN-γ, and p-STAT1.

Could Chinese herbs accelerate the resolution of reversible bronchiectasis in adults?: A case report

RATIONALE

The classic definition of bronchiectasis is of permanent bronchial dilatation. Therefore, bronchiectasis is generally considered irreversible in the adult population.

PATIENT CONCERNS

A 27-year-old woman presented to an affiliated hospital with a 1-year history of productive cough.

DIAGNOSIS

Bronchiectasis.

INTERVENTIONS

The patient was treated with cephalosporin and a mucus clearance regimen for 6 days and then with Chinese herbs for 3 months.

OUTCOMES

Reversible bronchial dilatation was evidenced by sequential chest high-resolution computed tomography 6 months later.

CONCLUSION

The current report demonstrated that, although rare in adult, bronchial dilatation might resolve completely in such a short period if receiving adequate regimens, for example, Chinese herbs.

Exploring the pharmacological mechanism of Yanghe Decoction on HER2-positive breast cancer by a network pharmacology approach

ETHNOPHARMACOLOGICAL RELEVANCE

Certain Chinese medicine formulae from traditional Chinese Medicine (TCM) are effective for treating and preventing diseases in clinical practice. Yanghe Decoction (YHD) is a Chinese medicine formula that is used to treat breast cancer, especially HER-positive breast cancer; however, the active compounds, potential targets, and pharmacological and molecular mechanism of its action against cancer remain unclear. Therefore, further investigation is required.

METHODS

A network pharmacology approach comprising drug-likeness evaluation, oral bioavailability prediction, Caco-2 permeability prediction, multiple compound target prediction, multiple know target collection, breast cancer genes collection, and network analysis has been used in this study.

RESULTS

Four networks are set up, including HER2-positive breast cancer network, compound-compound target network of YHD, YHD-HER2-positive breast cancer network and compound-known target-HER2-positive breast cancer network, and some HER2-positive breast cancer and YHD related targets, clusters, biological processes and pathways are found. We also found some potential anti-cancer compounds.

CONCLUSION

Our works successfully predict, illuminate and confirm the molecular synergy of YHD for HER2-positive breast cancer and found the potential HER2-positive breast cancer associated targets, cluster, biological processes and pathways. This study not only provide clues to the researcher who explores pharmacological and molecular mechanism of YHD acting on HER2-positive breast cancer, but also demonstrates a feasible method for discovering potential drugs from Chinese medicine formulae.

In vitro assays suggest Shenqi Fuzheng Injection has the potential to alter melanoma immune microenvironment

ETHNOPHARMACOLOGICAL RELEVANCE

A modern agent Shenqi Fuzheng Injection (SFI), prepared from Codonopsis Radix and Astragali Radix, has been commonly used as a supplementary therapy for cancers including melanoma. This agent was derived from a formula documented in the "National Collection of Chinese Medicine Prescriptions". The formula has long been used as a remedy for Qi deficiency that is closely associated with cancer-related fatigue and poor quality of life. However, the antimelanoma mechanisms of SFI remain unclear. Here we tested if SFI exerted antimelanoma effects by reprograming the tumour immune microenvironment using in vitro assays.

MATERIALS AND METHODS

The cytotoxic activities of Jurkat T cells when co-cultured with A375 cells were determined in the presence or absence of SFI. The migratory activities of Jurkat T cells were examined in the transwell assay system. The mRNA expression and production of cytokines (IL-10, TGF β and VEGF) in A375 cells in the presence or absence of SFI were determined by real-time PCR and ELISA, respectively.

RESULTS

When A375 cells were co-cultured with Jurkat T cells in the presence of SFI (220µg/mL), a potent cytotoxicity effect against A375 cells was observed. Supernatants from A375 cells that were treated with SFI (110 and 220µg/mL) significantly increased the migratory capacity of Jurkat T cells in transwell assays. SFI also markedly reduced the mRNA expression levels and the release of immunosuppressive cytokines IL-10, TGF-β and VEGF in A375 cells in a concentration-dependent manner.

CONCLUSIONS

SFI enhanced the cytotoxic and migratory activities of Jurkat T cells towards A375 melanoma cells. The effects were associated with SFI's suppression on immunosuppressive cytokines for their release from and gene expressions in A375 melanoma cells. These in vitro findings suggested that SFI might reprogramme the immunosuppressive melanoma microenvironment in vivo to enhance the cytotoxicity of tumour-infiltrating immune cells. This study provides a pharmacological basis for the adjunctive use of SFI in melanoma treatment.

Phytochemistry and Anticancer Potential of Notoginseng

Asian ginseng, American ginseng, and notoginseng are three major species in the ginseng family. Notoginseng is a Chinese herbal medicine with a long history of use in many Oriental countries. This botanical has a distinct ginsenoside profile compared to other ginseng herbs. As a saponin-rich plant, notoginseng could be a good candidate for cancer chemoprevention. However, to date, only relatively limited anticancer studies have been conducted on notoginseng. In this paper, after reviewing its anticancer data, phytochemical isolation and analysis of notoginseng is presented in comparison with Asian ginseng and American ginseng. Over 80 dammarane saponins have been isolated and elucidated from different plant parts of notoginseng, most of them belonging to protopanaxadiol or protopanaxatriol groups. The role of the enteric microbiome in mediating notoginseng metabolism, bioavailability, and pharmacological actions are discussed. Emphasis has been placed on the identification and isolation of enteric microbiome-generated notoginseng metabolites. Future investigations should provide key insights into notoginseng's bioactive metabolites as clinically valuable anticancer compounds.

Phytomedicine polypharmacology: Cancer therapy through modulating the tumor microenvironment and oxylipin dynamics

Integrative approaches in cancer therapy have recently been extended beyond the induction of cytotoxicity to controlling the tumor microenvironment and modulating inflammatory cascades and pathways such as lipid mediator biosynthesis and their dynamics. Profiling of important lipid messengers, such as oxylipins, produced as part of the physiological response to pharmacological stimuli, provides a unique opportunity to explore drug pharmacology and the possibilities for molecular management of cancer physiopathology. Whereas single targeted chemotherapeutic drugs commonly lack efficacy and invoke drug resistance and/or adverse effects in cancer patients, traditional herbal medicines are seen as bright prospects for treating complex diseases, such as cancers, in a systematic and holistic manner. Understanding the molecular mechanisms of traditional medicine and its bioactive chemical constituents may aid the modernization of herbal remedies and the discovery of novel phytoagents for cancer management. In this review, systems-based polypharmacology and studies to develop multi-target drugs or leads from phytomedicines and their derived natural products that may overcome the problems of current anti-cancer drugs, are proposed and summarized.

The advantages of using traditional Chinese medicine as an adjunctive therapy in the whole course of cancer treatment instead of only terminal stage of cancer

Recent studies indicate that Traditional Chinese medicine (TCM) can play an important role in the whole course of cancer treatment such as recovery stages of post-operative, radiotherapy or chemotherapy stages instead of only terminal stage of cancer. In this review, we have summarized current evidence for using TCM as adjuvant cancer treatment in different stages of cancer lesions. Some TCMs (e.g., TJ-41, Liu-jun-zi-tang, PHY906, Coumarin, and Aescine) are capable of improving the post-operative symptoms such as fatigue, pain, appetite, diarrhea, nausea, vomiting, and lymphedema. Some TCMs (e.g., Ginseng, Huang-Qi, BanZhiLian, TJ-48, Huachansu injection, Shenqi fuzheng injection, and Kanglaite injection) in combination with chemo- or radio-therapy are capable of enhancing the efficacy of and diminishing the side effects and complications caused by chemo- and radiotherapy. Taken together, they have great advantages in terms of suppressing tumor progression, relieving surgery complications, increasing the sensitivity of chemo- and radio- therapeutics, improving an organism's immune system function, and lessening the damage caused by surgery, chemo- or radio-therapeutics. They have significant effects on relieving breast cancer-related lymphedema, reducing cancer-related fatigue and pain, improving radiation pneumonitis and gastrointestinal side effects, protecting liver function, and even ameliorating bone marrow suppression. This review of those medicines should contribute to an understanding of Chinese herbal medicines as an adjunctive therapy in the whole course of cancer treatment instead of only terminal stage of cancer, by providing useful information for development of more effective anti-cancer drugs and making more patients "survival with cancer" for a long time.

The Immunoregulatory Effects of Traditional Chinese Medicine on Treatment of Asthma or Asthmatic Inflammation

Asthma is a chronic respiratory symptoms with variable airflow limitation and airway hyperresponsiveness (AHR), and causes high economic burden. Traditional Chinese medicine (TCM) has a long-lasting history of using herbal medicine in the treatment of various respiratory diseases including asthma. In the last several decades, an increasing number of herbs have been shown to be effective in the treatment of asthma in clinical trials or asthmatic inflammation in animal models. Literature about the effects of TCM on the immune system were searched in electronic databases such as PubMed, Google Scholar and Scopus from 2000 to 2014. 'TCM' and 'asthma' were used as keywords for the searches. Over 400 literatures were searched and the literatures about the immune system were selected and reviewed. We only reviewed literatures published in English. Accumulating evidence suggests that TCM can directly inhibit the activation and migration of inflammatory cells, regulate the balance of Th1/Th2 responses, and suppress allergic hyperreactivity through inducing regulatory T cells or attenuating the function of dendritic cells (DCs). These studies provided useful information to facilitate the use of TCM to treat asthma. This review was conducted to classify the findings based on their possible mechanisms of action reported.

Consistent Efficacy of Wendan Decoction for the Treatment of Digestive Reflux Disorders

Gastroesophageal reflux disease (GERD) and bile reflux gastritis (BRG) are common gastrointestinal (GI) disorders with unmet medical needs. Traditional Chinese medicine has long been used for the treatment of GERD and BRG whereas the ginger-containing formula Wendan decoction (WDD) targets homeostatic disturbances characterized by "reflux" and "gut-juice exposure" problems. Here we used WDD as a therapeutic tool to unravel the common pathogenesis of GI reflux disorders. Control clinical trials reporting the WDD-treated patients with GERD and BRG were included in this systematic review and meta-analysis. Outcome measurements were clinical efficacy defined by symptom relief with normal GI endoscopy, radiology, and pathology. Eventually, 33 studies involved 3253 participants (1351 vs. 1035 of the BRG in 20 publications, 449 vs. 418 of the GERD in 13 studies, and 194 vs. 159 of relapse rate in 6 trials). Pooled data showed a consistent therapeutic efficacy of WDD on BRG (OR = 6.00, 95%C = 4.68-7.69) and GERD (OR = 4.39, 95%CI = 2.72-7.07). The relapse rate was 12.4% for WDD, significantly lower than 44.0% for conventional therapies (OR = 0.14, 95%CI = 0.08-0.26). The consistent therapeutic efficacy of the single TCM formula on GERD and BRD indirectly indicates reflux as a common pathogenesis in reflux-associated GI disorders.