Patients’ demographics

An initial group of 151 adult patients were enrolled in the study after liver transplantation. Subjects with a chronic use of substances known to interfere with CYP3A metabolism (e.g., azole antifungals, macrolides, rifampin, phenytoin, carbamazepine) or those with incomplete pharmacokinetic or clinical data were excluded from the study. The final number of patients analyzed was thus reduced to 127 patients. Tacrolimus was used in 89 patients and cyclosporine was used in 38 patients. Patients received tacrolimus or cyclosporine as part of an immunosuppressive therapy according to liver transplantation unit—Ain Shams specialized hospital protocol. From the 127 enrolled patients, 99 patients were males and 28 patients were females. The mean age of the patients was 50.4 years. Table 1 shows the demographic and biochemical data of the study population immediately after liver transplantation.

Table 1 Demographic and biochemical data of the study population immediately after liver transplantationThe effect of different genotypes on CIs–DATL

Table 2 shows the association between genotypes and different tacrolimus DATLs. There was a statistically significant difference with a P value < 0.05 between the three genotypes in DATLs after doses 4 (P value = 0.000), 30 (P value = 0.000), 60 (P value = 0.007) and 90 (P value = 0.000) in CYP3A4 gene and in DATL 10 (P value = 0.003) and 20 (P value = 0.005) in PXR gene. The presence of T allele was associated with the highest DATL in patients received TAC. In the PXR gene, GG genotype showed the lowest DATLs after doses 10 and 20. For CYC, there was a statistically significant difference between the three genotypes in DATL 4 (P value = 0.025), 30 (P value = 0.045) and 90 (P value = 0.001) and the presence of T allele was associated with a highest DATL in CYP3A4 gene. In patients received CYC, DATLs 30 (P value = 0.001) and 60 (P value = 0.000) in PXR gene showed association with GG genotype and trough levels elevation was recorded with a statistically significant difference as shown in Table 3. The presence of G allele was associated with elevated DATLs.

Table 2 The association between genotypes and different tacrolimus DATLsTable 3 The association between genotypes and different cyclosporine DATLsGenotypes associations and correlations with clinical factors

The correlations between all clinical factors that affected DATL in each genotype are shown in Tables 4 and 5. About 432 correlations were tested to find the association between different clinical factors and DATLs in different CYP3A4 1B rs2740574 and PXR A7635G rs6785049 genotypes in both drugs.

Table 4 The correlations between the clinical factors and DATLs in different CYP3A4 genotypesTable 5 The correlations between the clinical factors and DATLs in different PXR genotypes

In CYP3A4 genotype CC, male sex was associated with elevated DATLs interpreted by strong positive correlations (r = 0.837) and statistically significant difference (P value = 0.019) in all DATLs, except DATL 60. Higher age was associated with elevated DATL 60 (P value = 0.040). It was expected that low Hg levels will be associated with higher DATLs, but this effect was disappeared in the results as shown in Table 4 and appeared only with DATL 60 as an inverse relationship between DATL and Hg without a clinically significant difference. Regarding T. Bil and D. Bil, it was expected that impaired liver capacity will lead to elevation in DATLs and resulted in many positive correlations, this assumption was recorded in DATLs 20, 30 and 60 with a statistically significant P value ranged from 0.000–0.019. It was expected that there will be an inverse correlation between albumin level and DATL, because reduced albumin level due to impaired liver functions will lead to higher free tacrolimus levels. The results revealed some inverse strong statistically significant correlations (r = -1, P value = 0.000) between albumin levels and DATLs in all times, except 20 and 30. In CYP3A4 genotype CT, male sex also was associated with positive correlations in all DATLs, except 10 (r = -0.047), but the statistically significant difference appeared only in DATL 30 (P value = 0.016) of tacrolimus and DATL 60 (P value = 0.000) of cyclosporine. There were not any statistically significant correlations between age and any DATL in both drugs. Hg correlations with DATLs were moderately positive in all times in both drugs with a statistically significant difference in DATLs 4 (r = 0.482, P value = 0.027) and 20 (r = 0.571, P value = 0.009) of tacrolimus and DATLs 10, 20, 30 and 60 (r = 1, P value = 0.000) of cyclosporine. A strong positive correlation with a statistically significant difference was appeared between T Bil and only DATLs 10 in both drugs (r = 0.473, P value = 0.023 for TAC and r = 1, P value = 0.000 for CYC), while it was appeared in the same DATLs 10 and D Bil in both drugs (r = 0.568, P value = 0.005 for TAC and r = 1, P value = 0.000 for CYC) and DATL 60 of cyclosporine (r = 1, P value = 0.000). The inverse correlations between albumin and DATLs appeared less frequently in the CT genotype, as it was recorded only in DATLs 10, 60 and 90 of tacrolimus without a statistically significant difference (r = -0.124,- 0.107 and - 0.144, respectively) and in DATLs 10, 20 and 60 of cyclosporine (r = -1) with a statistically significant difference as the P value = 0.000. In CYP3A4 genotype TT, unlike what detected in the CC genotype, male sex does not show the same patterns of positive correlations with different DATLs. There were inverse weak correlations between male sex and DATLs 4, 10, 30 and 60 of tacrolimus (r = -0.157, -0.082, -0.174 and -0.095, respectively) and DATL 4, 30 and 60 of cyclosporine (r = -0.296, -0.039 and -0.031, respectively) without any statistically significant difference. The majority of age and DATLs correlations showed an inverse result in this genotype and some of them were statistically significant. An inverse weak Hg/DATL correlation without statistically significant difference (P value > 0.05) appeared only with DATL 4 in both drugs (r = 0.030 for TAC and -0,144 for CYC). Unlike what happened in the CC genotype, total and direct bilirubin showed positive correlations in almost all DATLs in both drugs with a statistically significant difference in DATLs 4 (P-value = 0.003),10 (P value = 0.000) and 20 (P value = 0.000 and 0.001) of tacrolimus and DATLs 30 (P value = 0.011 and 0.007) and 90 (P value = 0.007 and 0.010) of cyclosporine. Unlike the CC genotype, the negative albumin levels correlations appeared less frequently with less statistically significance as these correlations appeared only in DATLs 4, 20 and 60 of tacrolimus and DATLs 4, 20, 30, 60 and 90 of cyclosporine and it was statistically significant only in DATL 20 (P value = 0.046) of CYC.

In PXR genotype AA, the majority of correlations showed an association between male sex and elevated DATLs in almost all times with a statistically significant difference in DATLs 20 (P value = 0.002), 30 (P value = 0.000), 60 (P value = 0.031) and 90 (P value = 0.017) of tacrolimus and 30 and 60 of cyclosporine (P value = 0.000) as shown in Table 5. The table also shows that there were inverse correlations between age and DATLs in almost all times, but the statistically significant difference appeared only in DATLs 20 (P value = 0.000) and 30 (P value = 0.016) of tacrolimus and 10 (P value = 0.000) and 90 (P value = 0.001) of cyclosporine. The positive correlations were detected between Hg and many DATLs and a statistically significant difference was recorded in DATL 4 (P value = 0.005) of TAC and 20 (P value = 0.016) and 30 (P value = 0.017) of CYC. The majority of correlations between Bil (T and D) and DATLs showed a positive relationship in all times and a statistically significant difference was detected between T Bil and DATL 90 of TAC (P value = 0.024) and D Bil and DATL 60 of CYC (P value = 0.026). Almost all albumin/DATLs correlations showed inverse relationships, but the statistically significant difference was appeared only in DATL 20 of cyclosporine (P value = 0.007). Unlike the AA genotype, in PXR genotype AG, half of the male sex/DATLs correlations showed inverse relationships without any statistically significant difference, but the majority of age/DATLs correlations showed inverse relationships and the statistically significant difference appeared only in DATL4 of tacrolimus (P value = 0.000) and 4 (P value = 0.028) and 30 (P value = 0.040) of cyclosporine. Like AA genotype, the negative Hg/DATLs correlations appeared in a few number of times and it was statistically significant only in DATL 4 of cyclosporine (P value = 0.002). In this genotype, the majority of total and direct bilirubin and DATLs showed a positive association and many of these correlations was statistically significant. This statistically significant difference appeared in the correlations between T Bil and DATLs 4 (P value = 0.000), 10 (P value = 0.001) and 90 (P value = 0.028) of TAC and 30 (P value = 0.041) and 90 (P value = 0.019) of CYC. In the correlations between D Bil and DATLs, the statistically significant difference appeared in DATLs 4 (P value = 0.004), 10 (P value = 0.007) and 90 (P value = 0.001) of TAC and 30 (P value = 0.004), 60 (P value = 0.000) and 90 (P value = 0.006) of CYC. Unlike the AA genotype, almost half the correlations between albumin and DATLs showed an inverse relationship and it was statistically significant only in DATL 90 of cyclosporine (P value = 0.023). In PXR genotype GG, unlike the AA, male sex was not associated with elevated DATLs in DATL 4, 10 and 20 of tacrolimus and DATL 20 of cyclosporine; negative correlations without statistically significant differences (P value > 0.05). Regarding age, some of the correlations were negative but the majority was positive with a statistically significant difference in DTAT 10 (P value = 0.000) of CYC. The same as age, Hg/DATLs correlations were mainly positive correlations with a statistically significant difference in DATLs 20 (P value = 0.000), 60 (P value = 0.001) and 90 (P value = 0.005) of TAC and 4 and 20 (P value = 0.000) of CYC. All the total and direct bilirubin correlations with DATLs were positive correlations, except in D4 of cyclosporine and the statistically significant difference detected between T Bil and DATL 20 (P value = 0.003) of TAC and (P value = 0.000) of CYC. Regarding D Bil, the statistically significant difference detected with DATLs 20 (P value = 0.006) and 30 (P value = 0.047) of TAC and DATL 20 (P value = 0.000) of CYC. Unlike the AA genotype, very few albumin/DATLs correlations showed an inverse relationship and the statistically significant difference appeared only in the DATL 4 (P value = 0.011) of TAC.

The impaired liver capacity presented by liver function tests post-transplantation

CIs are mainly metabolized by liver, and impairment of liver functions post-liver transplantation may affect significantly CIs metabolism. Figure 1 shows that the patterns of resuming liver functions post-transplantation through detecting the percentages of patients had elevations in liver function tests (AST, ALT. Alk. Ph, GGT and total protein) till day 90 of transplantation.

Fig. 1

Impaired liver function tests during follow-up period

The figure shows that the percentages of elevated liver function tests decline with time after liver transplantation in all patients except for GGT. The percentages of patients with reduced total protein also decline with time following liver transplantation.

The results highlighted that the presence of T allele of CYP 3A4 and G allele of PXR was associated with highest DATLs in many patients. Unexpected associations were revealed between different DATLs and serum Hg and albumin in different genotypes may be because of the presence of many other interacting factors. Almost All liver function tests improved by time after liver transplantation.