coronary artery disease ( cad ) remains the principal cause of mortality and morbidity around the world [ 1 , 2 ] .
although the mechanisms are still not entirely resolved , previous studies have demonstrated that an imbalance between t - helper 1- ( th1- ) mediated and th2-mediated immune functions contributes to the development of atherosclerosis .
recently , th17 , which are a newly defined subset different from th1 and th2 , reactive to autoantigens are involved in the pathogenesis of several autoimmune diseases [ 4 , 5 ] .
in addition to th1 , th2 , and th17 lineage , regulatory t cells ( tregs ) , a special subset of cd4 t cells , inhibit atherosclerosis development by attenuating activated t cell responses [ 6 , 7 ] .
inspiringly , previous clinical and experimental studies from our laboratory have found that th17/tregs functional imbalance exists during atherogenesis , indicating that the imbalance of th17/tregs plays a critical role in cad [ 8 , 9 ] .
hence , these findings have showed that cd4 t cell subpopulations play an important role in the initiation and progression of atherosclerosis .
it is well known that cd4 t cells are divided into different subsets depending on the cytokines they produce .
interferon- ( ifn- )  , the principal cytokine of th1 cells , is proinflammatory and exacerbates atherosclerotic disease , while the th2 cytokine such as interleukin- ( il- ) 4 is considered to be mainly atheroprotective and can neutralize th1 cytokine activity [ 1012 ] .
moreover , hashmi and zeng have found that il-17 and il-17 induced cytokines ( il-6 and il-8 ) were significantly increased in acs patients .
interestingly , tregs exert antiatherosclerosis partly by secretion of anti - inflammatory cytokine transforming growth factor ( tgf-1 ) , which can in turn induce the expression of forkhead box transcription factor p3 ( foxp3 ) and promote differentiation of tregs derived from cd4cd25 t cells [ 15 , 16 ] . therefore , these findings suggest that cytokines as those mentioned above are also essential for the formation and progression of the atherosclerotic plaque
. the galectin family is characterized by conserved carbohydrate recognition domains ( crd ) that can bind glycosylated proteins .
galectins are involved in a wide range of biologic processes such as cell adhesion and migration , proliferation and apoptosis , tumor biology , and regulation of the immune system .
galectin- ( gal- ) 9 is a member of the galectin family of carbohydrate - binding proteins comprising two carbohydrate recognition domains connected by a linker peptide .
gal-9 is mainly expressed by eosinophils , endothelial cells , macrophages , dcs , kupffer cells , vascular endothelial cells , intestinal epithelial cells , and in particular t lymphocytes .
furthermore , gal-9 is believed to function predominantly as a multifaceted player in adaptive and innate immunity , especially in t cell development and homeostasis [ 2023 ] .
accumulating evidence shows that gal-9 induces apoptosis in subsets of differentiated t cells , particularly in th1 and th17 cells , and stimulates the activity of tregs [ 19 , 2428 ] .
indeed , treatment with recombinant gal-9 moderated the progression of experimental autoimmune encephalomyelitis ( eae ) , arthritis , and diabetes in animal models [ 19 , 2931 ] , by reducing the number of th1 and th17 cells and downregulating circulating ifn- levels .
t cell immunoglobulin mucin- ( tim- ) 3 has been identified as a receptor for gal-9 .
although gal-9 can function in a tim-3-independent fashion , the immune - regulatory effects of gal-9 are largely attributed to gal-9-tim-3 pathway [ 3235 ] .
more recently , foks et al . demonstrated that anti - tim-3-ab administration promoted atherosclerotic plaque formation , which indicated that tim-3-gal-9 pathway may be concerned with the development of atherosclerosis .
thus , it is reasonable to postulate that gal-9 may be involved in atherosclerosis based cad .
in addition , several findings strongly support the original experimental observations that gal-3 plays an important role in the underlying heart failure ( hf ) processes and that elevation of gal-3 is associated with disease progression and poor outcome in hf [ 3739 ] .
herein , we investigate serum gal-9 levels in chinese patients with cad , and the severity of coronary arteries stenosis was evaluated by gensini score .
furthermore , ifn- , il-4 , il-17 , tgf-1 , high - sensitivity c - reactive protein ( hs - crp ) , and the classical atherosclerosis risk factors were evaluated .
additionally , th1 , th2 , th17 , and cd4cd25foxp3 tregs differentiation were detected in pbmc cultures exposed to gal-9 .
232 patients presenting at the department of cardiology of huazhong university of science and technology affiliated union hospital between jan .
2013 with suspected or established cad were recruited , including 149 males and 83 females .
they were divided into four groups : ( 1 ) the control group , which consisted of 50 subjects with nca ( 28 men and 22 women , mean age 56.7  11.7 ) ; ( 2 ) sap group ( 25 men and 15 women , mean age 62.4  10.0 , inclusion criteria : typical chest discomfort that was associated with horizontal or downsloping st - segment depression > 1  mm in an exercise test ) ; ( 3 ) nsteacs group ( 60 men and 30 women , mean age 60.6  9.9 , which included unstable angina pectoris ( uap ) and non - st - segment elevation myocardial infarction ( nstemi ) , inclusion criteria : chest pain at rest with definite ischemic electrocardiographic changes , t - wave inversions and/or st - segment changes , or typical ischemic chest pain which persists for more than 20  min , elevated serum myocardial necrosis markers concentration and dynamic evolution , but not the typical st - elevation electrocardiogram ) ; ( 4 ) stemi group ( 36 men and 16 women , mean age 54.1  12.3 , inclusion criteria : myocardial infarction that was confirmed by a significant increase of serum creatine kinase mb , troponin i levels , and elevation of st - segment )
. furthermore , all participants underwent coronary angiography after admission and completed a standardized questionnaire about previous and present illness , medication history , and smoking status .
cardiovascular - interrelated factors , such as age , body mass index ( bmi ) , gender , and ejection fraction ( ef ) were estimated via physical examination , ultrasonic cardiography ( ucg ) , and electrocardiogram ( ecg ) , respectively .
patients with the following characteristics were excluded from study enrollment : valvular heart disease , thromboembolism , autoimmune diseases ( systemic lupus erythematosus , rheumatoid arthritis , etc . ) , collagen disease , disseminated intravascular coagulation , severe liver and kidney disease , symptomatic heart failure , trauma or surgery , or malignant disease .
the study was approved by the ethics committee of tongji medical college of huazhong university of science and technology , and all participants were provided written informed consent prior to study entry .
two experienced cardiologists , who were not aware of the patients ' clinical and biochemical results , visually examined angiographic images to assess the extent and severity of cad .
cad diagnosis was made according to the presence of 50% stenosis in 1 main coronary artery .
the stenosis severity of cad was assessed by gensini score as previously described . in the ami group ,
the blood was drawn with a 21-gauge needle for clean venipuncture of an antecubital vein and the samples were collected into sodium heparin vacutainers ( becton - dickinson ) .
after centrifugation , the serum obtained was stored at 80c until further use to measure the concentration of gal-9 .
the level of gal-9 was measured by elisa according to the manufacturer 's instructions ( r&d systems ) .
in addition , the levels of ifn- , il-17 ( bolingkewei biotechnology , china ) , il-4 , hs - crp ( huijia biotechnology , china ) , and tgf-1 ( fumeng gene biotechnology , china ) were measured by elisa , following the manufacturer 's instructions .
the minimal detectable concentrations were 28  pg / ml for gal-9 , 1.8  pg / ml for ifn- , 1.8  pg / ml for il-17 , 0.4  pg / ml for il-4 , 22  pg / ml for hs - crp , and 8  pg / ml for tgf-1 .
the intra - assay and interassay coefficients of variation for all elisa were < 5% and < 10% , respectively .
all the other biochemical measurements , including serum total cholesterol ( tc ) , triglyceride ( tg ) , low - density lipoprotein cholesterol ( ldl - c ) , high - density lipoprotein cholesterol ( hdl - c ) , apolipoprotein a - i ( apoa - i ) , apolipoprotein b ( apob ) , lipoprotein(a ) , creatinine , fasting plasma glucose ( fpg ) , uric acid , and cardiac troponin i ( ctni ) , were carried out by the biochemical laboratory of our cardiovascular institute using standard methods . peripheral blood mononuclear cells ( pbmcs ) from nca ( excluded from hypertension , diabetes , and dyslipidemia ) were isolated by ficoll - hypaque density gradient centrifugation ( pharmacia lkb technology , uppsala , sweden ) .
cells from the interphase were collected and washed twice with dulbecco 's phosphate buffered saline ( d - pbs ) .
remaining erythrocytes were removed using lysis buffer ( 4.14  g nh4cl , 0.5  g khco3 , and 18.6  mg na2edta in 500  ml water , ph = 7.4 and sterilized ) for 5  min on ice .
pbmcs were resuspended in rpmi1640 ( lonza , verviers , belgium ) supplemented with 2.5% fcs , penicillin ( 100  u / ml)/streptomycin ( 100  u / ml ) , and sodium pyruvate ( 1  mm , sigma ) .
pbmcs were stimulated with anti - human cd3 and anti - human cd28 antibodies ( both 2  g / ml , sanquin ) in the presence of recombinant gal-9 ( m ) ( 0.010.1  m , prospec - tany technogene ltd .
, israel ) for 24  h. cells were allocated into tubes and washed once in phosphate buffered saline ( pbs ) . for tregs analysis
, the cells were incubated with anti - cd4-fitc - hab and anti - cd25-apc - hab ( bd pharmingen ) . after the surface staining
, the cells were stained with anti - foxp3-pe - hab ( bd pharmingen ) after fixation and permeabilization according to the manufacturer 's instructions . for analysis of th1 , th2 , and th17 cells ,
the cells were stimulated with phorbol myristate acetate ( pma , 20  ng / ml , alexis biochemicals , san diego , ca ) and ionomycin ( 1  g / ml , alexis biochemicals ) for 4  h in the presence of 2  mol / ml monensin ( alexis biochemicals ) . the incubator was set at 37c under a 5% co2 environment .
after culture for 4 hours , the cells were collected for staining according to the instructions .
fixation and permeabilization were necessary before staining with anti - ifn--pe- , anti - il-4-pe- , or anti - il-17-pe- hab ( bd pharmingen ) .
continuous variables are summarized as mean  standard deviation ( sd ) , and categorical data are presented as percentages . the shapiro - wilk test was used to assess the normality of distribution of continuous variables . in order to compare two groups ,
continuous variables were tested using the independent samples t - test for normally distributed data and the mann - whitney u test for nonnormally distributed data ; the chi - square test was used for categorical variables . when three or more groups were compared , one - way anova was used .
if significance was found , newman - keuls test was performed for post hoc analysis to detect the difference among groups .
multiple stepwise regression analysis was used to evaluate the influence of different variables on gal-9 and to adjust for covariates .
independent factors were sex , age , ctni , and the metabolic - related variables including bmi , fpg , lipid profiles , and hs - crp . to determine the independent predictors for the presence and severity of cad , all the conventional risk factors associated with cad were tested in multiple stepwise regression analysis .
the prevalence of smoking and the levels of tg , lipoprotein(a ) , fpg , creatinine , hs - crp , and ctni were significantly higher in patients with cad compared to patients with nca group ( all p < 0.05 ) .
however , other biochemical results , including tc , hdl - c , ldl - c , and uric acid , were similar between nca and cad patients .
compared with stemi group , patients in sap and nsteacs groups showed markedly higher hdl - c levels and age and lower levels of lipoprotein(a ) , fpg , hs - crp , and ctni ( all p < 0.01 ) . compared to patients with sap ,
the use of aspirin , -blockers , and statins was rare in patients with acs ( all p < 0.05 ) , whereas the levels of lipoprotein(a ) and hs - crp were markedly higher in patients with acs ( all p < 0.01 ) .
a significant increase of creatinine levels was observed in patients with stemi compared with nsteacs group ( p < 0.05 ) and an obvious decrease of uric acid levels was found in patients with stemi compared to sap group ( p < 0.01 ) .
unexpectedly , the distribution of hypertension , diabetes mellitus , dyslipidemia , and family history was similar among patients with acs and sap . among the total 232 study participants , serum gal-9 levels ranged from 1733.86 to 5259.39  pg / ml .
compared with the nca group , patients with cad had significantly lower levels of gal-9 ( 3283.55  587.59 versus 3565.97  544.37  pg / ml , p < 0.05 ; figure 1(a ) ) .
in addition , we found that serum gal-9 levels were significantly lower in the stemi ( 3126.36  637.7 
pg / ml ) than those in the sap group ( 3607.91  541.35  pg / ml ) or the nca group ( stemi versus sap and nsteacs versus sap , all p < 0.01 ; stemi versus nca and nsteacs versus nca , all p < 0.01 ; figure 1(b ) ) .
interestingly , serum gal-9 levels did not differ significantly between patients with nsteacs and stemi ( p > 0.05 ) , nor was there a difference between the sap and nca groups ( p > 0.05 ; figure 1(b ) ) .
as shown in figure 2 , serum il-17 , il-4 , ifn- , and tgf-1 were detected in each group .
the il-17 and ifn- concentrations in patients with stemi ( il-17 , 57.16  16.14  pg / ml ; ifn- , 13.43  5.29 
pg / ml ) and nsteacs ( il-17 , 47.68  14.46  pg / ml ; ifn- , 11.28  4.23 
pg / ml ) were significantly higher compared with those in patients with sap ( il-17 , 26.94  9.09  pg / ml ; ifn- , 6.05  2.41  pg / ml ) and nca groups ( il-17 , 24.00  10.14  pg / ml ; ifn- , 5.83  2.12  pg / ml ) ( all p < 0.01 ; figures 2(a ) and 2(c ) ) .
il-4 concentrations showed no difference in any of the groups ( stemi , 7.25  3.82  pg / ml ; nsteacs , 7.22  3.87  pg / ml ; sap , 8.12  4.48  pg / ml ; nca , 6.83  3.25 
tgf-1 concentrations in patients with stemi ( 4.08  2.13  ng / ml ) and nsteacs ( 4.73  2.71  ng / ml ) were significantly lower than those in patients with sap ( 8.03  3.88  ng / ml ) and nca ( 9.02  4.86  ng / ml ) ( all p < 0.01 ; figure 2(d ) ) . importantly , gal-9 levels were negatively correlated with il-17 ( r = 0.45 , p < 0.001 ; figure 3(a ) ) and ifn- ( r = 0.53 , p < 0.001 ; figure 3(c ) ) but positively associated with tgf-1 ( r = 0.58 , p < 0.001 ; figure 3(d ) ) . however , gal-9 levels showed no correlation with il-4 concentrations ( r = 0.04 , p = 0.528 ; figure 3(b ) ) . to detect the involvement of gal-9 in the induction of differentiation of human cd4 t cells
gal-9 expanded the number of cd4cd25foxp3 tregs ( control , 6.99  1.61% ; gal-9 ( 0.01  m ) , 9.24  2.04% ; gal-9 ( 0.03  m ) , 10.27  3.04% ; gal-9 ( 0.1  m ) , 11.24  3.23% ) and decreased the development of th17 ( control , 0.628  0.239% ; gal-9 ( 0.01  m ) , 0.418  0.171% ; gal-9 ( 0.03  m ) , 0.214  0.064% ; gal-9 ( 0.1  m ) , 0.059  0.015% ) dose dependently ( figures
4(c ) and 4(d ) ) , with resulting increase in secretion of tgf-1 ( control , 165.3  48.6  pg / ml ; gal-9 ( 0.01  m ) , 227.8  72.4  pg / ml ; gal-9 ( 0.03  m ) , 312.9  81.7  pg / ml ; gal-9 ( 0.1  m ) , 528.1  97.4 
pg / ml ) and suppressed il-17 production ( control , 132.4  23.6  pg / ml ; gal-9 ( 0.01  m ) , 110.3  25.7 
pg / ml ; gal-9 ( 0.03  m ) , 81.9  18.0  pg / ml ; gal-9 ( 0.1  m ) , 56.6  13.8 
however , the development of th1 and th2 cells and secretion of ifn- and il-4 in the supernatant were similar in the gal-9 untreated and treated pbmcs ( figures 4(a ) , 4(b ) , and 4(e ) ) .
as we expected , gal-9 levels were found to be negatively correlated with hs - crp ( r = 0.37 , p < 0.001 ; figure 5(a ) ) , the gensini score ( r = 0.23 , p = 0.001 ; figure 5(b ) ) , fpg ( r = 0.15 , p = 0.027 ; figure 5(c ) ) , and lipoprotein(a ) ( r = 0.16 , p = 0.012 ; figure 5(d ) ) but positively associated with creatinine ( r = 0.21 , p = 0.002 ; figure 5(e ) ) and age ( r = 0.14 , p = 0.028 ; figure 5(f ) ) . to determine
which variables were independently associated with gal-9 , multiple stepwise regression analysis using gal-9 as the dependent variable identified sex , age , bmi , fpg , tc , tg , hdl - c , ldl - c , hs - crp , lipoprotein(a ) , creatinine , uric acid , ctni , and therapeutic use of statins as independent variables . after adjustments , only hs - crp ( b = 72.158 , p < 0.001 ) , lipoprotein(a ) ( b = 8.333 , p = 0.045 ) , creatinine ( b = 5.228 , p < 0.001 ) , and use of therapeutic statins ( b = 362.29 , p < 0.001 ) retained significance for independently predicting gal-9 ( table 3 ) . in order to determine which variables
gensini score was the dependent variable , and sex , age , bmi , fpg , lipid profiles , gal-9 , hs - crp , uric acid , traditional risk factors , and statins were independent variables .
after adjustments , only gal-9 ( b = 0.145 , p = 0.011 ) , age ( b = 0.276 , p < 0.001 ) , and lipoprotein(a ) ( b = 0.280 , p <
in the present study , we found that participants with cad had lower serum gal-9 levels compared with nca . furthermore , serum gal-9 levels in the acs group were significantly lower than those in the sap or nca group .
moreover , gal-9 was found to be independently associated with hs - crp , lipoprotein(a ) , and creatinine .
notably , gal-9 suppressed t - helper 17 ( th17 ) and expanded regulatory t cells ( tregs ) as analyzed within the activated cd4 t cell population , resulting in decreased il-17 production and increased secretion of tgf-1 .
to the best of our knowledge , this is the first study to investigate the relation of serum gal-9 levels with the presence and the severity of coronary arteries stenosis .
mor et al . have reported that cd4cd25 tregs deficiency enhanced atherosclerotic lesion development in ldlr mice , and adoptive transfer of cd4cd25 tregs attenuated the initiation and progression of atherosclerosis in apoe mice [ 42 , 43 ] . moreover
, our laboratory has detected that th17/treg functional imbalance exists in patients with acs , suggesting a potential role for th17/treg imbalance in plaque destabilization and the onset of acs [ 8 , 9 ] .
of note , gal-9 is a multifunctional modulator of t cell immunity with apoptotic effects on th17 cells and stimulatory activity on tregs in autoimmune diseases . in line with this publication
, we found that gal-9 was able to induce cd4cd25foxp3 tregs development and inhibit th17 differentiation in activated pbmcs of nca .
therefore , we speculated that gal-9 plays an immune - regulatory role in atherosclerosis via its effects on tregs and th17 cells .
acs patients have significantly higher il-17 and il-17 induced cytokines ( il-6 and il-8 ) , while the pleiotropic cytokine ifn- is a proinflammatory regulator that is expressed at high levels in atherosclerotic lesions .
in addition , it has been demonstrated that increased expression of tgf-1 is a stabilizing factor in human atherosclerotic plaques . in this study
, we also found that il-17 and ifn- concentrations in patients with stemi and nsteacs were significantly higher compared with those in patients with sap and nca , while tgf-1 concentrations in patients with stemi and nsteacs were significantly lower than those in patients with sap and nca .
these results again confirmed that inflammatory cytokines mentioned above have differential effects in atherosclerosis based cad .
interestingly , gal-9 levels were showed to be negatively correlated with il-17 and ifn- but positively associated with tgf-1 .
furthermore , we found that gal-9 was able to increase secretion of tgf-1 and decrease il-17 secretion in activated pbmcs .
consequently , our data in vitro imply a protective role for gal-9 in atherosclerosis via expanding tgf-1 and suppressing il-17 secretion .
however , the precise effect and mechanism of gal-9 in atherosclerosis are still to be elucidated in atherosclerosis animal models .
surprisingly , we found that the development of th1 cells and secretion of ifn- in the supernatant were similar in gal-9 untreated and treated pbmcs , since zhu et al . reported that gal-9 induces apoptosis in th1 cells .
this discrepancy may be ascribed to the diverse concentrations of gal-9 and different incubation periods . additionally , il-4 concentrations in the supernatant showed no difference in gal-9 untreated and treated pbmcs .
this result further confirms that the effect of il-4 is still controversial [ 45 , 46 ] , reflecting its dual pro- and anti - inflammatory character .
moreover , there are numerous publications showing that gal-9 has proinflammatory effects in addition to its immune - suppressive effects , especially through its actions on cells of the innate immune system like dc and nk cells [ 47 , 48 ] .
thus , these results indicate that gal-9 has bidirectional effects like many immune - regulatory molecules .
our data showed that cad patients had lower serum gal-9 levels than those without cad , and gal-9 was independently associated with the gensini score in patients with cad .
these results suggest that low serum gal-9 levels are associated with the presence and the severity of coronary arteries stenosis .
previous studies have elucidated that serum biomarkers are recognized as important tools for prediction , diagnosis , risk stratification , and therapeutic decision - marking for patients with cad .
accumulating studies demonstrated that atherosclerotic lesion instability and rupture induced by inflammation are the major mechanisms of acs [ 50 , 51 ] .
recently , a large number of clinical experiments have reported that hs - crp is not only a biomarker of inflammations and atherosclerosis , but also a marker of atheromatous plaque vulnerability [ 5254 ] . in our study , patients with acs had higher serum hs - crp levels compared to patients with sap . of note , gal-9 was found to be independently associated with hs - crp .
hence , low serum concentrations of gal-9 may take part in the onset of acs and may act as a predictor of atheromatous plaque vulnerability .
however , whether a causal relationship exists between the two processes is still to be studied .
several lines of evidence indicate that lipoprotein(a ) is an independent risk factor for patients with cad [ 55 , 56 ] .
all these findings together suggest that gal-9 might be a potential independent biomarker of cad .
interestingly , our data showed that serum gal-9 levels were higher in patients of cad complicated with t2 dm than those of cad without t2 dm ( data not shown ) .
's study reporting that serum gal-9 levels are elevated in the patients with type 2 diabetes ( t2 dm ) and chronic kidney disease ( ckd ) .
however , serum gal-9 levels were decreased in cad and elevated in the patients with t2 dm .
this paradox could be attributed to the fact that atherosclerosis is highly multifactorial , tregs and gal-9 being only some factors among many others .
the exact mechanism is still to be elucidated but different diseases may have divergent immune states .
worth noting is the fact that the serum gal-9 level seems relatively higher in our study than in the previous studies [ 22 , 57 ] .
the differences among these studies might be explained , at least partly , by different experimental designs , different number and characteristics of participants recruited , ethnical differences , medical treatments , lack of standardization of methods for the determination of serum gal-9 levels , and different ways in which samples were handled . nevertheless , several limitations of the present study should be considered .
firstly , the number of study participants ( 232 ) was relatively small . secondly , given the cross - sectional design of the study , the causal relationship between gal-9 level and the severity of coronary artery stenosis can not be determined .
thirdly , different methods of assessment of the coronary stenosis and the criterion for diagnosis of the diseased artery may lead to another result . finally , although we accounted for confounding of traditional cardiovascular risk factors , a potential for uncontrolled or residual confounding that could influence the relationship between gal-9 and cad would be plausible . in conclusion
, we have shown that low serum gal-9 levels are associated with the presence and the severity of coronary arteries stenosis .
importantly , gal-9 can expand cd4cd25foxp3 tregs and inhibit th17 development in activated pbmcs , leading to increased secretion of tgf-1 and decreased il-17 secretion .
our observations provide evidence of the role of gal-9 in cad and that gal-9 is an independent negative predictor of acs , which may also at least partially explain the protection of gal-9 against coronary atherosclerotic plaque vulnerability .
large - scale population - based clinical studies and further experimental studies are needed to elucidate the exact effect and potential biological mechanisms of gal-9 in the pathogenesis of cad and to evaluate whether gal-9 is a potential novel biomarker of cad .
 
 background . 
 recently , several studies suggest that galectin-9 ( gal-9 ) might play a pivotal role in the pathogenesis of autoimmune diseases . 
 however , the exact role of gal-9 in atherosclerosis remains to be elucidated . 
 methods . 
 serum gal-9 , high - sensitivity c - reactive protein ( hs - crp ) , interferon- ( ifn- )  , interleukin- ( il- ) 4 , il-17 , and transforming growth factor- ( tgf- ) 1 were measured . 
 the effect of gal-9 on peripheral blood mononuclear cells ( pbmc ) was investigated in patients with normal coronary artery ( nca ) . 
 results . the lowest level of gal-9 was found in the st - segment elevation myocardial infarction ( stemi ) group , followed by the non - st - segment elevation acs ( nsteacs ) , the nca , and the stable angina pectoris ( sap ) groups , respectively . 
 additionally , gal-9 was found to be independently associated with hs - crp , lipoprotein(a ) , and creatinine . 
 notably , gal-9 was also noted to be an independent predictor of the gensini score . 
 moreover , gal-9 suppressed t - helper 17 ( th17 ) and expanded regulatory t cells ( tregs ) , resulting in decreased il-17 production and increased secretion of tgf-1 . 
 conclusions . 
 serum gal-9 is associated with not only coronary artery disease ( cad ) , but also the severity of coronary arteries stenosis . 
 gal-9 can expand tregs and suppress th17 development in activated pbmc , implying that gal-9 has the potential to dampen the development of atherosclerosis and may be a new therapy for cad . 
1. Introduction
2. Materials and Methods
3. Results
4. Discussion