Colorectal Cancer and Subsequent Diabetes Risk: A Population-based Cohort Study in Taiwan

CONTEXT

The association between colorectal cancer (CRC) and new-onset diabetes mellitus remains unclear.

OBJECTIVE

To examine the association between CRC and the risk of subsequent diabetes mellitus and to further investigate the impact of chemotherapy on diabetes mellitus risk in CRC.

DESIGN

A nationwide cohort study.

METHODS

Using the Taiwan Cancer Registry Database (2007-2018) linked with health databases, 86,268 patients with CRC and an equal propensity score-matched cohort from the general population were enrolled. Among them, 37,277 CRC patients from the Taiwan Cancer Registry (2007-2016) were analyzed for diabetes mellitus risk associated with chemotherapy. Chemotherapy exposure within 3 years of diagnosis was categorized as no chemotherapy, <90 days, 90-180 days, and >180 days. Differences in diabetes mellitus risk were assessed across these categories.

RESULTS

Each group involved 86,268 participants after propensity score matching. The patients with CRC had a 14% higher risk of developing diabetes mellitus than the matched general population (hazard ratio [HR]: 1.14, 95% confidence interval [CI]: 1.09-1.20). The highest risk was observed within the first year after diagnosis followed by a sustained elevated risk. Long-term chemotherapy (>180 days within 3 years) was associated with a 60-70% increased risk of subsequent diabetes mellitus (HR: 1.64, 95% CI: 1.07-2.49).

CONCLUSION

Patients with CRC are associated with an elevated risk of diabetes mellitus, and long-term chemotherapy, particularly involving capecitabine, increases diabetes mellitus risk. Thus, monitoring blood glucose levels is crucial for patients with CRC, especially during extended chemotherapy.

The oncologic outcome and prognostic factors for solitary colorectal liver metastasis after liver resection

BACKGROUND

Studies on prognostic factors for patients undergoing surgery to treat solitary liver metastases originating from colorectal cancer (CRC) are limited. This study aimed to analyze significant prognostic factors associated with tumor recurrence and long-term survival after liver resection for solitary colorectal liver metastasis.

METHODS

Data from 230 patients with solitary liver metastases from CRC who received liver resection between 2010 and 2019 were retrospectively analyzed. Recurrence-free survival (RFS) and overall survival (OS) were accessed with the Kaplan-Meier method and log-rank test. Cox regression multivariate analysis identified independent variables associated with RFS and OS. Nomograms were developed to predict patient outcomes after surgery.

RESULTS

The 3- and 5-year OS rates were 72.3% and 59.8%, respectively. The 3- and 5-year RFS rates were 40.0% and 27.1%, respectively. Multivariate analysis revealed age ≥ 70 years, resection margin width < 10 mm, initial N2 stage, hypoalbuminemia before surgery, and neutrophil-to-lymphocyte ratio (NLR) ≥ 3 after surgery as independent prognostic factors for OS. For RFS, initial N2 stage, hypoalbuminemia before surgery, NLR ≥ 3 after surgery, elevated carcinoembryonic antigen (CEA) levels after surgery, and CEA ratio (after/before liver resection) < 0.3 were identified as independent prognostic factors.

CONCLUSION

This study demonstrated that initial N2 stage, hypoalbuminemia before liver resection, and NLR ≥ 3 after liver resection exert a significant association on the RFS and OS of patients undergoing surgery for solitary liver metastases from CRC. Thus, upfront chemotherapy, prompt postoperative chemotherapy, and intensive postoperative surveillance are mandatory for patients having these adverse factors.

Tumor Marker Trajectories and Survival Analysis in Patients With Normal Carcinoembryonic Antigen Ranges After Colorectal Cancer Resection

BACKGROUND

Evidence regarding postoperative CEA for predicting long-term outcomes of colorectal cancer remains controversial, especially in patients with normal postoperative CEA.

OBJECTIVE

To investigate the risk difference among different postoperative CEA trajectories in patients with normal postoperative CEA after curative colorectal cancer resection.

DESIGN

This cohort study was conducted at a comprehensive cancer center and included data retrieved from a prospectively collected database between January 2006 and December 2018.

SETTINGS

Retrospective cohort study.

PATIENTS

Patients with colorectal cancer who underwent surgery for primary stage I to III colorectal adenocarcinoma were included and those with postoperative CEA >5 ng/mL were excluded.

INTERVENTIONS

Standard curative radical resection was performed.

MAIN OUTCOME MEASURES

Ten-year overall survival and disease-free survival were analyzed.

RESULTS

The study population (n = 8156) was categorized into 6 trajectories: persistent-ultralow (n = 2351), persistent-low (n = 2474), gradually decrease (n = 401), persistent-medium (n = 1727), slightly increase (n = 909), and around-upper-limit (n = 394). The median follow-up time was 7.8 years, and the median time frame in which CEA was measured to determine trajectory was 2.6 years. The persistent-ultralow group had the highest 10-year overall survival (85.1%) and disease-free survival (82.7%). The around-upper-limit group had the lowest 10-year overall survival (55.5%) and disease-free survival (53.4%). The adjusted HR trend was comparable to the crude HR of the persistent-ultralow group. Consequently, the higher initial serum CEA groups had higher HRs of overall survival and disease-free survival. The adjusted HR of overall survival was 2.96 (95% CI, 2.39-3.66) and of disease-free survival was 2.66 (95% CI, 2.18-3.69) for the around-upper-limit groups.

LIMITATIONS

Retrospective design.

CONCLUSIONS

The postoperative serum CEA trajectory is an independent factor associated with long-term outcomes. Although CEA levels were all within normal range, higher levels of postoperative serum CEA trajectory correlated with worse long-term oncological outcomes. See Video Abstract.

TRAYECTORIAS DE MARCADORES TUMORALES Y ANLISIS DE SUPERVIVENCIA EN PACIENTES CON RANGOS NORMALES DE ANTGENO CARCINOEMBRIONARIO POSTERIOR A RESECCIN DE CNCER COLORRECTAL

ANTECEDENTES:La evidencia sobre el CEA post operatorio para la predicción de los resultados a largo plazo del cáncer colorrectal sigue siendo controversial, especialmente en pacientes con CEA post quirúrgico normal.OBJETIVO:Investigar la diferencia de riesgo entre diferentes trayectorias postoperatorias del CEA en pacientes con CEA post quirúrgico normal tras la resección curativa del cáncer colorrectal.DISEÑO:Este estudio de cohorte se realizó en un centro oncológico integral e incluyó datos recuperados de una base de datos recopilada prospectivamente entre enero de 2006 y diciembre de 2018.AJUSTES:Estudio de cohorte retrospectivo.PACIENTES:Se incluyeron pacientes con el diagnostico de CCR que fueron sometidos a cirugía por adenocarcinoma colorrectal primario en estadio I-III. Se excluyeron pacientes con CEA postoperatorio >5 ng/mL.INTERVENCIONES:Se realizó una resección radical curativa estandarizada.PRINCIPALES MEDIDAS DE RESULTADO:Se analizaron la supervivencia general a diez años y la supervivencia libre de enfermedad.RESULTADOS:La población de estudio (n = 8156) fue clasificada en seis trayectorias, que incluyeron ultrabajo persistente (n = 2351), bajo persistente (n = 2474), disminución gradual (n = 401), medio persistente (n = 1727), aumento leve (n = 909) y alrededor del límite superior (n = 394). La mediana del tiempo de seguimiento fue de 7,8 años y la mediana del período de tiempo en el que el CEA fue medido para determinar la trayectoria fue de 2,6 años. El grupo ultrabajo persistente tuvo la mayor supervivencia general a 10 años (85,1 %) y supervivencia libre de enfermedad (82,7 %). El grupo alrededor del límite superior tuvo la supervivencia general a 10 años más baja (55,5 %) y la supervivencia libre de enfermedad (53,4 %). La tendencia del índice de riesgo ajustado fue comparable al índice de riesgo bruto del grupo ultrabajo persistente. En consecuencia, los grupos con CEA sérico iniciales más altos tenían índices de riesgos más altos de supervivencia general y supervivencia libre de enfermedad. Los índices de riesgos ajustados de supervivencia general/supervivencia libre de enfermedad fueron 2,96/2,66 (intervalo de confianza del 95 %: 2,39-3,66/2,18-3,69) para los grupos cercanos al límite superior.LIMITACIONES:El estudio estuvo limitado por su diseño retrospectivo.CONCLUSIONES:La trayectoria del CEA sérico postoperatorio es un factor independiente asociado con resultados a largo plazo. Aunque los niveles de CEA se encontraban todos dentro del rango normal, los niveles más altos de trayectoria del CEA en suero posoperatorio se correlacionaron con peores resultados oncológicos a largo plazo. (Traducción-Dr Osvaldo Gauto ).

Diabetic severity and oncological outcomes of colorectal cancer following curative resection: A population-based cohort study in Taiwan

BACKGROUND

Although diabetes is a poor prognostic factor for colorectal cancer (CRC), whether diabetes severity provides an additional predictive value for CRC prognosis remains unclear. The study aimed to investigate the prognostic differences after curative CRC resection among patients with different diabetic severities.

METHODS

This population-based retrospective cohort study analyzed data registered between 2007 and 2015 in the Cancer Registry Database, which is linked to the National Health Insurance Research Database and National Death Registry. Patients with CRC who underwent curative radical resection for stage I-III disease were evaluated, with their diabetic status subdivided into no diabetes, diabetes without complication, and diabetes with complications. Cox regressions were applied to determine the association between diabetes severity and CRC survival, including overall survival (OS), disease-free survival (DFS), time to recurrence, and cancer-specific survival (CSS).

RESULTS

A total of 59,202 patients with CRC were included. Compared with the no diabetes group, the diabetes without complication group has insignificantly worse OS (hazard ratio [HR], 1.05; 95% confidence interval [CI], 1.01-1.09), DFS (HR, 1.08; 95% CI, 1.04-1.12), and CSS (HR, 0.98; 95% CI, 0.93-1.03), whereas those with complicated diabetes had a significantly higher risk of poor survival (OS: HR, 1.85; 95% CI, 1.78-1.92; DFS: HR, 1.75; 95% CI, 1.69-1.82; CSS: HR, 1.41; 95% CI, 1.33-1.49). Patients with CRC and diabetes also had a higher risk of recurrence than did those without diabetes. Sex and TNM staging were important effect modifiers.

CONCLUSIONS

Among patients with CRC who undergo curative resection, the severity of the diabetes is inversely correlated with long-term outcomes, especially in women and patients in the earlier stages of CRC.

PLAIN LANGUAGE SUMMARY

The prognostic impact of diabetes severity in colorectal cancer (CRC) is yet to be clarified. In this cohort study of 59,202 patients with CRC, compared with patients with CRC and without diabetes, those with uncomplicated diabetes had an insignificantly worse CRC survival, whereas those with complicated diabetes had a significantly higher risk of poor survival. Multidisciplinary medical care to prevent progression into diabetes with complications is needed to improve survival among patients with CRC and diabetes.

Localization of Colorectal Cancer Lesions in Contrast-Computed Tomography Images via a Deep Learning Approach

Abdominal computed tomography (CT) is a frequently used imaging modality for evaluating gastrointestinal diseases. The detection of colorectal cancer is often realized using CT before a more invasive colonoscopy. When a CT exam is performed for indications other than colorectal evaluation, the tortuous structure of the long, tubular colon makes it difficult to analyze the colon carefully and thoroughly. In addition, the sensitivity of CT in detecting colorectal cancer is greatly dependent on the size of the tumor. Missed incidental colon cancers using CT are an emerging problem for clinicians and radiologists; consequently, the automatic localization of lesions in the CT images of unprepared bowels is needed. Therefore, this study used artificial intelligence (AI) to localize colorectal cancer in CT images. We enrolled 190 colorectal cancer patients to obtain 1558 tumor slices annotated by radiologists and colorectal surgeons. The tumor sites were double-confirmed via colonoscopy or other related examinations, including physical examination or image study, and the final tumor sites were obtained from the operation records if available. The localization and training models used were RetinaNet, YOLOv3, and YOLOv8. We achieved an F1 score of 0.97 (±0.002), a mAP of 0.984 when performing slice-wise testing, 0.83 (±0.29) sensitivity, 0.97 (±0.01) specificity, and 0.96 (±0.01) accuracy when performing patient-wise testing using our derived model YOLOv8 with hyperparameter tuning.

Metformin increases pathological responses to rectal cancers with neoadjuvant chemoradiotherapy: a systematic review and meta-analysis

BACKGROUND

To summarize the chemo-radio effect of metformin in rectal cancers with neoadjuvant chemoradiotherapy on pathological response, tumor regression grade (TRG), and T/N downstaging.

METHODS

PubMed, MEDLINE, Embase, and Cochrane Database of collected reviews were searched up to June 30, 2022. This study conducted systematic review and meta-analysis based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) sheet. Odds ratios (ORs) and confidence intervals (CIs) which calculated by random-effects models were displayed in forest plots. Newcastle-Ottawa scale was used to assess the risk of bias of the observational cohort studies.

RESULTS

This systematic review and meta-analysis comprised eight cohorts out of seven studies, with 2294 patients in total. We performed two-way comparison for metformin in diabetic patients vs (1) non-metformin drugs in diabetic patients and (2) nondiabetic patients. In diabetes patient studies, the metformin group had a significantly increased pathological response on TRG (OR: 3.28, CI: 2.01-5.35, I² = 0%, p < 0.001) and T downstaging (OR: 2.14, CI: 1.24-3.67, I² = 14%, p = 0.006) in comparison with a non-metformin group. When compared with nondiabetic patients, the pathological response on TRG (OR: 2.67, CI: 1.65-4.32, I² = 43%, p < 0.001) and T downstaging (OR: 1.96, CI: 1.04-3.71, I² = 66%, p = 0.04) were also higher in metformin group. The limitation was that no randomized controlled trials were available based on current literature review. Small sample sizes for diabetic metformin or non-metformin users in rectal cancer patients reduced the power of the study.

CONCLUSIONS

For patients with rectal cancer and treated with neoadjuvant chemoradiotherapy, metformin administration in diabetic patients increased the pathological response on tumor-regression grade and T downstaging. Further well-designed, high-quality randomized controlled trials are required to reveal the actual effect of metformin.

Upfront primary tumor resection versus upfront systemic therapy for metastatic colorectal cancer: a systematic review and meta-analysis

PURPOSE

The standard initial treatment for metastatic colorectal cancer (mCRC) remains debated. This study investigated whether upfront primary tumor resection (PTR) or upfront systemic therapy (ST) provides better survival outcomes for patients with mCRC.

METHODS

The PubMed, Embase, Cochrane Library, and ClinicalTrials.gov databases were searched for studies published at any time from January 1, 2004, to December 31, 2022. Randomized controlled trials (RCTs) and prospective or retrospective cohort studies (RCSs) utilizing propensity score matching (PSM) or inverse probability treatment weighting (IPTW) were included. We evaluated overall survival (OS) and short-term (60-day) mortality in these studies.

RESULTS

After reviewing 3,626 articles, we identified 10 studies including a total of 48,696 patients. OS differed significantly between the upfront PTR and upfront ST arms (hazard ratio [HR] 0.62; 95% CI: 0.57-0.68; p < 0.001). However, a subgroup analysis identified no significant difference in OS in RCTs (HR 0.97; 95% CI: 0.7-1.34; p = 0.83), whereas significant difference in OS occurred between the treatment arms in RCSs with PSM or IPTW (HR 0.59; 95% CI: 0.54-0.64; p < 0.001). Short-term mortality was analyzed in three RCTs, and 60-day mortality differed significantly between the treatment arms (risk ratio [RR] 3.52; 95% CI: 1.23-10.10; p = 0.02).

CONCLUSIONS

In RCTs, upfront PTR for mCRC did not improve OS and enhanced the risk of 60-day mortality. However, upfront PTR seemed to increase OS in RCSs with PSM or IPTW. Therefore, whether upfront PTR should be used for mCRC remains unclear. Further large RCTs are required.

Effect of short-course radiotherapy followed by oxaliplatin-based consolidation chemotherapy on organ preservation in locally advanced rectal cancer

PURPOSE

We analyzed the effectiveness, safety, and mid-term oncological outcomes of short-course radiotherapy (SCRT) and oxaliplatin-based consolidation chemotherapy in patients with locally advanced rectal cancer (LARC).

METHODS

We retrospectively evaluated 64 patients with LARC who underwent SCRT and tegafox (tegafur-uracil/leucovorin plus oxaliplatin) or mFOLFOX-6 (5-fluorouracil, leucovorin, and oxaliplatin) consolidation chemotherapy before surgery between January 2015 and December 2020. Tumor response, patient compliance, toxicity, surgical outcomes, overall survival (OS), and disease-free survival (DFS) were analyzed.

RESULTS

Sixty-four patients with a mean age of 58.67 years (44 males) were included; 48 (75%) had tumors within 5 cm of the anal verge. Additionally, 93.8% of the patients underwent at least 2 months of chemotherapy, and three required dose reduction. Grade III toxicity occurred in 2 patients, and 10 had a clinical complete response and opted for non-operative management. One patient experienced tumor progression and underwent further treatment without surgery. Among the 53 patients who underwent surgery, 51 (96.2%) had sphincter preservation, 3 had Clavien-Dindo grade III complications, and no mortality occurred. The complete response rate for the entire cohort was 23.4%. Moreover, 47 patients (74.6%) had a neoadjuvant rectal score of < 16 after treatment. After a median follow-up time of 32.01 months, 6 (9.3%) had local recurrence, and 17 (26.6%) had distant metastasis. The 3-year OS, DFS and stoma-free rates were 89.5%, 65.5%, and 78.1% respectively.

CONCLUSION

SCRT followed by oxaliplatin-based consolidation chemotherapy is safe and effective for tumor downstaging in LARC, further improving the sphincter preservation rate.

Skin Toxicity as a Predictor of Survival in Metastatic Colorectal Cancer Patients Treated with Anti-EGFR: Fact or Fallacy?

The primary treatment for metastatic colorectal cancer (mCRC) consists of targeted therapy and chemotherapy to improve survival. A molecular target drug with an anti-epidermal growth factor receptor (EGFR) antagonist is recommended when the RAS and BRAF genes are normal. About 50–70% of patients using anti-EGFR antagonists will experience skin reactions. Some studies have shown that severe skin reactions caused by anti-EGFR antagonists may be linked to overall survival (OS) and progression-free survival (PFS), but the results are still uncertain. These data of mCRC patients who underwent anti-EGFR therapy between October 2017 and October 2018 were analyzed retrospectively. A total of 111 patients were included in this study. The survival results showed that gender, age, body mass index, primary tumor site, and recurrence did not significantly affect OS and PFS. However, the first-line anti-EGFR inhibitor treatment was significantly associated with OS (p < 0.001) and PFS (p < 0.001). There was no significant difference in the incidence of acne between males and females in grades 1 and 2, while males have a greater risk in grades 3 and 4 than females (20.3 vs. 4.8%; p-value = 0.041). Skin toxicity was not a predictor of anti-EGFR treatment response in this investigation.

Potential short-term outcome advantage of low vs. high ligation of inferior mesenteric artery for sigmoid and rectal cancer: propensity score matching analysis

BACKGROUND

Whether to ligate the inferior mesenteric artery at its root during anterior resection for sigmoid colon or rectal cancer is still under debate. This study compared the surgical outcomes, postoperative recovery, and anastomotic leakage between high and low ligation of the inferior mesenteric artery through a subgroup analysis.

METHODS

This was a retrospective analysis of prospectively collected data. All patients who underwent colorectal resection for rectosigmoid cancer between December 2016 and December 2019 were enrolled. According to the surgical ligation level of the inferior mesenteric artery, the patients were categorized into either the high or low ligation group. The investigated population was matched using the propensity score method.

RESULTS

Overall, 894 patients with sigmoid or rectal cancer underwent elective anterior resection with high (577 patients) or low (317 patients) ligation of the inferior mesenteric artery. After the propensity score matching, 245 patients in each group were compared. High ligation of the inferior mesenteric artery was associated with higher incidence of anastomotic leakage (14.9% vs. 5.6%, P = 0.041) for mid- to low-rectum tumors and a higher incidence of complications (8.6% vs. 3.3%, P = 0.013) of grades 1-2 according to the Clavien-Dindo classification system.

CONCLUSION

Compared with high ligation, low ligation of the inferior mesenteric artery resulted in lower likelihood of morbidity and mortality in rectal and sigmoid cancers. Moreover, low ligation was less likely to result in anastomosis leakage in mid- to low-rectal cancers.

Advantage of laparoscopic surgery in patients with generalized obesity operated for colorectal malignancy: A retrospective cohort study

Background

Because of the progression of minimally invasive surgery skills and obesity in colorectal surgery, we aimed to evaluate the short-term outcomes of colorectal cancer resections in patients with generalized obesity at a single teaching hospital with mature surgical techniques and training programs.

Methods

A total of 537 patients were diagnosed with CRC and had a body mass index ≥30 kg/m² between January 2009 and December 2019 at a single institution. 265 patients underwent open surgery and 272 patients underwent laparoscopic surgery. Data were analysed to explore the independent risk factors for postoperative complications.

Results

The laparoscopic group had less blood loss (73 ± 128 vs. 148 ± 290 ml, p < 0.001) and a shorter postoperative hospital stay (10.8 ± 17.1 vs. 11.7 ± 6.8 days, p < 0.001) than the open group. The number of harvested lymph nodes did not significantly differ between the two groups (30.9 ± 18.3 vs. 30.2 ± 15.3, p = 0.981). Although anastomotic leakage was significantly higher in the laparoscopic group (1.5% vs. 4.8%, p = 0.030), there were also similar overall postoperative morbidity and mortality rates between the open and laparoscopic groups for CRC patients with generalized obesity who underwent surgery.

Conclusion

Laparoscopic surgery can reduce blood loss, decrease the length of hospital stay, obtain a similar number of harvested lymph nodes, and achieve an acceptable conversion rate for CRC patients with generalized obesity. We suggest that laparoscopic surgery could become a standard method for CRC treatment in patients with generalized obesity.

Preoperative Cancer Inflammation Prognostic Index as a Superior Predictor of Short- and Long-Term Outcomes in Patients with Stage I-III Colorectal Cancer after Curative Surgery

Inflammatory reactions play a crucial role in cancer progression and may contribute to systemic inflammation. In routine clinical practice, some inflammatory biomarkers can be utilized as valuable predictors for colorectal cancer (CRC). This study aims to determine the usefulness of a novel cancer-inflammation prognostic index (CIPI) marker derived from calculating carcinoembryonic antigen (CEA) multiplied by the neutrophil-to-lymphocyte ratio (NLR) values established for non-metastatic CRCs. Between January 1995 and December 2018, 12,092 patients were diagnosed with stage I to III primary CRC and had radical resection—they were all included in this study for further investigation. There were 5996 (49.6%) patients in the low-CIPI group and 6096 (50.4%) patients in the high-CIPI group according to the cutoff value of 8. For long-term outcomes, the high-CIPI group had a significantly higher incidence of recurrence (30.6% vs. 16.0%, p < 0.001) and worse relapse-free survival (RFS) and overall survival (OS) rates (p < 0.001). High CIPI was an independent prognostic factor for RFS and OS in univariate and multivariate analyses. This research is the first to document the independent significance of CIPI as a prognostic factor for CRC. To ensure that it works, this CIPI needs to be tested on more CRC prediction models.

Usefulness of close surveillance for rectal cancer patients after neoadjuvant chemoradiotherapy

It is controversial whether patients who achieve clinical complete remission (cCR) of rectal cancer should be treated with the “watch and wait” (W&W) or radical resection (RR) strategy. Our study aimed to compare the survival outcomes and ostomy rate of the W&W and RR strategies. Between January 2008 and December 2015, we investigated 26 patients who achieved pathologic complete remission after undergoing RR and 36 patients who adopted the W&W strategy because of cCR. The tumor regrowth, salvage surgery, recurrence, disease-free, and overall survival (OS) rates were assessed. In our study, recurrences occurred in nine and two patients from the W&W and RR groups, respectively. Each patient in the RR group had a temporary or permanent ostomy, but only three (8.3%) had an ostomy in the W&W group. The 5-year recurrence rate was 25.0% in the W&W group and 7.7% in the RR group. Six patients (16.7%) had tumor regrowth in the W&W group, and all were resectable when regrowth. The 5-year OS rates between the two groups were nonsignificant. There is no specific risk factor for recurrence and OS. Under close surveillance, the W&W group achieved similar OS to the RR group and benefited from a lower ostomy rate.

Comparison of short-term and medium-term outcomes between intracorporeal anastomosis and extracorporeal anastomosis for laparoscopic left hemicolectomy

BACKGROUND

Few studies have evaluated the feasibility and safety of intracorporeal anastomosis (IA) for left hemicolectomy. Here, we aimed to investigate the potential advantages and disadvantages of laparoscopic left hemicolectomy with IA and compare the short- and medium-term outcomes between IA and extracorporeal anastomosis (EA).

METHODS

We retrospectively analyzed 133 consecutive patients who underwent laparoscopic left hemicolectomies from July 2016 to September 2019 and categorized them into the IA and EA groups. Patients with stage 4 disease and conversion to laparotomy or those lost to follow-up were excluded. Postoperative outcomes between IA and EA groups were compared. Short-term outcomes included postoperative pain score, bowel function recovery, complications, duration of hospital stay, and pathological outcome. Medium outcomes included overall survival and disease-free survival for at least 2 years.

RESULTS

After excluding ineligible patients, the remaining 117 underwent IA (n = 40) and EA (n = 77). The IA group had a shorter hospital stay, a shorter time to tolerate liquid or soft diets, and higher serum C-reactive protein level on postoperative day 3. There was no difference between two groups in operative time, postoperative pain, specimen length, or nearest margin. A 2-year overall survival (IA vs. EA: 95.0% vs. 93.5%, p = 0.747) and disease-free survival (IA vs. EA: 97.5% vs. 90.9%, p = 0.182) rates were comparable between two groups.

CONCLUSIONS

Laparoscopic left hemicolectomy with IA was technically feasible, with better short-term outcomes, including shorter hospital stays and shorter time to tolerate liquid or soft diets. The IA group had higher postoperative serum C-reactive protein level; however, no complications were observed. Regarding medium-term outcomes, the overall survival and disease-free survival rates were comparable between IA and EA procedures.

Tegafur-Uracil/Leucovorin Plus Oxaliplatin (TEGAFOX) as Consolidation Regimen after Short-Course Radiotherapy Is Effective for Locally Advanced Rectal Cancer

This study aimed to explore the safety and efficacy of neoadjuvant SCRT and tegafur−uracil/leucovorin plus oxaliplatin (TEGAFOX) for LARC in comparison to those of the modified 5-fluorouracil, leucovorin, and oxaliplatin (mFOLFOX-6) regimen. We retrospectively evaluated 15 and 22 patients with LARC who underwent SCRT, followed by consolidation chemotherapy with TEGAFOX and mFOLFOX-6 before surgery, respectively, between January 2015 and December 2019. The primary endpoint was the tumor response rate. The secondary endpoints were compliance, toxicity, complications, overall survival (OS), and disease-free survival (DFS). The dose reduction rate was lower in the TEGAFOX group (0 vs. 9.1% (n = 2)). No grade III-IV toxicities occurred in the TEGAFOX group. Two and four patients in the TEGAFOX and mFOLFOX-6 groups, respectively, achieved clinical complete responses. The pathologic complete response rate was lower in the TEGAFOX group (7.7% vs. 17.6%). Overall, 11 (73.3%) and 17 (81.0%) patients had a neoadjuvant rectal (NAR) score of <16 in the TEGAFOX and mFOLFOX-6 groups, respectively. All patients in this study received sphincter-preservation surgery. One patient in each group developed Clavien−Dindo grade III complications. There were no significant between-group differences in the 3-year OS (81.8% vs. 84.8%, p = 0.884) and 3-year DFS (72% vs. 71.6%, p = 0.824) rates. TEGAFOX, as consolidation chemotherapy after SCRT, achieves good tumor downstaging and patient compliance in LARC. The toxicity, complications, and surgical outcomes are similar to those of mFOLFOX-6. Thus, TEGAFOX can be considered a chemotherapy option for rectal cancer treatment.

Neoadjuvant Short-Course Radiotherapy Followed by Consolidation Chemotherapy before Surgery for Treating Locally Advanced Rectal Cancer: A Systematic Review and Meta-Analysis

Neoadjuvant short course radiotherapy (SCRT) followed by consolidation chemotherapy (CCT) is an alternative treatment for locally advanced rectal cancer (LARC). We performed this systematic review and meta-analysis to explore the tumor response and oncological outcomes of this new approach compared to conventional chemoradiotherapy (CRT). An online search of the PubMed, Embase, and Cochrane Library databases was performed. This review included 7507 patients from 14 different cohorts. The pCR rate was higher with SCRT + CCT than that with CRT (RR: 1.60; 95% CI: 1.35−1.91; p < 0.01). SCRT + CCT provided a higher ypN0 response (RR: 1.06; 95% CI: 1.01−1.12; p = 0.02). There were no differences in R0 resection and positive CRM rates; however, more sphincter-preservation surgeries were performed in the SCRT + CCT arm (RR: 1.06; 95% CI: 1.01−1.11; p = 0.02). There was no difference in the OS and DFS between the SCRT + CCT and the CRT arms (OS: HR: 0.85, p = 0.07; DFS: HR: 0.88, p = 0.08). The compliance and toxicity were comparable between the SCRT and CRT groups. In the subgroup analysis, patients who underwent four or more cycles of CCT had better pCR and DFS events. Therefore, SCRT followed by consolidation chemotherapy might be an effective alternative treatment for LARC.

Increased standardised incidence ratio of cardiovascular diseases among colorectal cancer patients

PURPOSE

Evidence regarding the relationship between colorectal cancer and the risk of cardiovascular disease (CVD) is limited. Thus, in this study, we aimed to determine the standardised incidence ratio (SIR) of CVDs in colorectal cancer patients in Taiwan.

METHODS

A population-based cohort study enrolling the incident colorectal cancer population based on the Cancer Registry Database from 2007 to 2016 was conducted (n = 94,233, mean age: 62.4 years, 43.0% women). New cases of CVD, including coronary heart disease and ischemic stroke, through 31 December 2018 were obtained from the National Health Insurance Research Database and National Death Registry. Compared with the general population (n = 1,977,659, mean age: 44.3 years, 49.6% women), age- and sex-specific SIRs for CVDs were calculated by the time since diagnosis.

RESULTS

A total of 6852 cardiovascular events occurred in colorectal cancer patients during a median follow-up of 4.4 years. The SIR of CVD was highest in the first year after diagnosis (SIR: 1.45, 95% confidence interval: 1.39-1.50); however, this decreased to the same value as that of the general population in later years. Similar patterns were observed for the SIR of coronary heart disease. However, the SIR of ischemic stroke among colorectal cancer patients was low from the second year following cancer diagnosis.

CONCLUSIONS

Colorectal cancer patients are at an increased risk of developing CVD, especially coronary heart disease, during the first 3 years following colorectal cancer diagnosis.

Transrectal natural orifice specimen extraction in left hemicolectomy for tumours around the splenic flexure: Old wine in new bottles

AIM

Laparoscopic anterior resection with natural orifice specimen extraction (NOSE) has favourable short-term outcomes. However, NOSE is rarely adopted for left hemicolectomy procedures. This study aimed to review the feasibility, safety and short-term outcomes of transrectal NOSE in patients undergoing laparoscopic left hemicolectomy.

METHOD

All consecutive patients who underwent laparoscopic left hemicolectomy surgery with transrectal NOSE in a single institution between January 2018 and December 2020 were reviewed. Transrectal NOSE was performed with an enterotomy at the upper rectum. The specimen was brought out via a transanal endoscopic microsurgery scope inserted through the anus. A supplementary video demonstrates this technique. Surgical outcomes, including complications, postoperative short-term recovery and the level of pain intensity, are presented.

RESULTS

Twenty patients were reviewed. There were no immediate postoperative complications and no wound infections in these patients. The average time to tolerate a soft diet was 3.6 days, and the average postoperative hospital stay was 4.5 days. The average score on the numerical rating scale of postoperative pain was 3.0 on postoperative day 1. The median follow-up time was 23.5 months.

CONCLUSION

Laparoscopic left hemicolectomy with transrectal NOSE is a safe and feasible procedure that leads to early postoperative recovery and a short hospital stay.

Decreasing Postoperative Pulmonary Complication Following Laparoscopic Surgery in Elderly Individuals with Colorectal Cancer: A Competing Risk Analysis in a Propensity Score-Weighted Cohort Study

Simple Summary

As the effect of laparoscopic surgery on elderly patients with colorectal cancer (CRC) remains unclear, this propensity score–weighted cohort study revealed that laparoscopic surgery is a favorable method for elderly patients with CRC than open surgery in terms of less pulmonary-related postoperative morbidity and mortality, less hospital stay and similar oncological outcomes.

Abstract

Advanced age is a risk factor for major abdominal surgery due to a decline in physical function and increased comorbidities. Although laparoscopic surgery provides good results in most patients with colorectal cancer (CRC), its effect on elderly patients remains unclear. This study aimed to compare the short- and long-term outcomes between open and laparoscopic surgeries in elderly patients with CRC. Total 1350 patients aged ≥75 years who underwent curative resection for stage I–III primary CRC were enrolled retrospectively and were divided into open surgery (846 patients) and laparoscopy (504 patients) groups. After propensity score weighting to balance an uneven distribution, a competing risk analysis was used to analyze the short-term and long-term outcomes. Postoperative mortality rates were lower in the laparoscopy group, especially due to pulmonary complications. Postoperative hospital stay was significantly shorter in the laparoscopy group than in the open surgery group. Overall survival, disease-free survival, and competing risk analysis showed no significant differences between the two groups. Laparoscopic surgery for elderly patients with CRC significantly decreased pulmonary-related postoperative morbidity and mortality in this large cohort study. Laparoscopic surgery is a favorable method for elderly patients with CRC than open surgery in terms of less hospital stay and similar oncological outcomes.

Deciding the operation type according to mismatch repair status among hereditary nonpolyposis colorectal cancer patients: should a tailored approach be applied, or does one size fit all?

BACKGROUND

Although extended colectomy (EC) was recommended for HNPCC patients, previous studies did not show significantly improved overall survival. Immunohistochemical (IHC) stain of mismatch repair (MMR) gene protein expression is now a feasible and reliable test clinically. Therefore, we tried to investigate whether we could use MMR IHC stain to select operation types in HNPCC patients.

PATIENTS AND METHODS

Between 1995 and 2013, 186 HNPCC patients were collected. Status of MMR protein expression, perioperative clinic-pathological variables and post-operative follow up status were analyzed by multivariate analyses.

RESULTS

Sixty-five percent (121 of 186) patients of these HNPCC patients demonstrated loss of at least one MMR protein. There were several significant differences existing between deficient MMR (dMMR) and proficient MMR (pMMR) subgroups in terms of clinic-pathological characteristics. With the average follow-up duration of 93.9 months, we observed significantly high risk of developing metachronous CRC between SC and EC subgroups (crude rate 8.5% vs. 0%, p = 0.035). However, no significant difference was observed among the presence of extra-colonic tumors (12.4% vs. 5.8%, p = 0.284). The positive and negative prediction rate of metachronous CRC in dMMR subgroup was 12.8 and 87.2% while 1.9 and 98.1% in the pMMR subgroup. Survival outcomes were significantly affected by MMR status and resection types by multivariate analysis. Significantly better OS in dMMR subgroup (HR = 0.479, 95% CI: 0.257-0.894, p = 0.021) comparing with pMMR subgroup was observed. However, significant improved DFS (HR = 0.367, 95% CI: 0.172-.0787, p = 0.010) but not significant for OS (HR = 0.510, 95% CI: 0.219-1.150, p = 0.103) for EC subgroup compared with SC subgroup. Differences existing among different subgroups by combing extent of resection and MMR status. In dMMR subgroup, SC, compared with EC, demonstrated significantly worse DFS by multivariate analyses (HR = 3.526, 95% CI: 1.346-9.236, p = 0.010) but not for OS (HR = 2.387, 95% CI: 0.788-7.229, p = 0.124), however, no significantly differences of OS and DFS in pMMR subgroup between SC and EC were found.

CONCLUSIONS

Significantly better overall survival and higher rate of metachronous CRC exist in dMMR subgroup of HNPCC patients comparing with pMMR subgroup. Extended colectomy significantly improved DFS and was thus recommended for dMMR subgroup but not pMMR subgroup of HNPCC patients.

A Prediction Model for Metachronous Peritoneal Carcinomatosis in Patients with Stage T4 Colon Cancer after Curative Resection

(1) Background: The aim of this study was to develop a prediction model for assessing individual mPC risk in patients with pT4 colon cancer. Methods: A total of 2003 patients with pT4 colon cancer undergoing R0 resection were categorized into the training or testing set. Based on the training set, 2044 Cox prediction models were developed. Next, models with the maximal C-index and minimal prediction error were selected. The final model was then validated based on the testing set using a time-dependent area under the curve and Brier score, and a scoring system was developed. Patients were stratified into the high- or low-risk group by their risk score, with the cut-off points determined by a classification and regression tree (CART). (2) Results: The five candidate predictors were tumor location, preoperative carcinoembryonic antigen value, histologic type, T stage and nodal stage. Based on the CART, patients were categorized into the low-risk or high-risk groups. The model has high predictive accuracy (prediction error ≤5%) and good discrimination ability (area under the curve >0.7). (3) Conclusions: The prediction model quantifies individual risk and is feasible for selecting patients with pT4 colon cancer who are at high risk of developing mPC.

Prognostic value of the C-reactive protein to albumin ratio in colorectal cancer: an updated systematic review and meta-analysis

Backgrounds

The inflammatory biomarker “C-reactive protein to albumin ratio (CAR)” has been reported to significantly correlate to a variety of human cancers. However, there are conflicting results regarding the prognostic value of CAR in colorectal cancer. Previous studies mainly assessed patients in Eastern countries, so their findings may not be applicable to the Western population. Therefore, this updated meta-analysis aimed to investigate the prognostic value of pre-treatment CAR and outcomes of patients with colorectal cancer.

Methods

We conducted a systematic search for eligible literature until October 31, 2020, using PubMed and Embase databases. Studies assessing pre-treatment CAR and outcomes of colorectal cancer were included. Outcome measures included overall survival, disease-free survival, progression-free survival, and clinicopathological features. The pooled hazard ratios (HR) with 95% confidence intervals (CI) were used as effective values.

Results

A total of 15 studies involving 6329 patients were included in this study. The pooled results indicated that a high pre-treatment CAR was associated with poor overall survival (HR 2.028, 95% CI 1.808−2.275, p < 0.001) and poor disease-free survival/progression-free survival (HR 1.768, 95% CI 1.321–2.365, p < 0.001). Subgroup analysis revealed a constant prognostic value of the pre-treatment CAR despite different study regions, sample size, cancer stage, treatment methods, or the cut-off value used. We also noted a correlation between high pre-treatment CAR and old age, male sex, colon cancer, advanced stage (III/IV), large tumor size, poor differentiation, elevated carcinoembryonic antigen levels, neutrophil-to-lymphocyte ratio, and the modified Glasgow prognostic score.

Conclusions

High pre-treatment CAR was associated with poor overall survival, disease-free survival, and progression-free survival in colorectal cancer. It can serve as a prognostic marker for colorectal cancer in clinical practice.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12957-021-02253-y.

The risk factors of local recurrence and distant metastasis on pT1/T2N0 mid-low rectal cancer after total mesorectal excision

Background

Radical resection is associated with good prognosis among patients with cT1/T2Nx rectal cancer. However, still some of the patients experienced cancer recurrence following radical resection. This study tried to identify the postoperative risk factors of local recurrence and distant metastasis separately.

Methods

This retrospective, single-center study comprised of 279 consecutive patients from Linkou branch of Chang Gung Memorial Hospital in 2005–2016 with rectal adenocarcinoma, pT1/T2N0M0 at distance from anal verge ≤ 8cm, who received curative radical resection.

Results

The study included 279 patients with pT1/pT2N0 mid-low rectal cancer with median follow-up of 73.5 months. Nineteen (6.8%) patients had disease recurrence in total. Nine (3.2%) of them had local recurrence, and fourteen (5.0%) of them had distant metastasis. Distal resection margin < 0.9 (cm) (hazard ratio = 4.9, p = 0.050) was the risk factor of local recurrence. Preoperative carcinoembryonic antigen (CEA) ≥ 5 ng/mL (hazard ratio = 9.3, p = 0.0003), lymph node yield (LNY) < 14 (hazard ratio = 5.0, p = 0.006), and distal resection margin < 1.4cm (hazard ratio = 4.0, p = 0.035) were the risk factors of distant metastasis.

Conclusion

For patients with pT1/pT2N0 mid-low rectal cancer, current multidisciplinary treatment brings acceptable survival outcome. Insufficient distal resection margin attracted the awareness of risk factors for local recurrence and distant metastasis as a foundation for future research.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12957-021-02223-4.

Short- and medium-term outcomes of intracorporeal versus extracorporeal anastomosis in laparoscopic right colectomy: a propensity score-matched study

BACKGROUNDS

Though better short-term outcomes were frequently reported, differences in specimen parameters and the rate of subsequent peritoneal recurrence between intracorporeal anastomosis (IA) and extracorporeal anastomoses (EA) for laparoscopic right hemicolectomy have not been analyzed. We aimed to compare the pathologic differences and oncological outcomes between these two approaches.

METHODS

We retrospectively analyzed 217 consecutive patients who underwent laparoscopic right hemicolectomies from September 2016 to April 2018 and classified them into IA and EA groups, based on the approach used. Propensity score matching analysis was performed, after which 101 patients were included in each group with the patients matched for demographics, tumor stage, and localization.

RESULTS

The IA group had a longer operative time, shorter length of stay, shorter time to first flatus and tolerating a soft diet, and better pain scale scores at postoperative day 3. No inter-group differences in conversion, postoperative complication, mortality, or readmission rates were found. The IA group had a longer resected colon length (23.67 vs. 19.75 cm, p = 0.010) and nearest resected margin (7.51 vs. 5.40 cm, p = 0.010) for cancer near the hepatic flexure. There are comparable 3-year overall survival (87.7% vs. 89.6%, p = 0.604) and disease-free survival (75.0% vs. 75.7%, p = 0.842) between the IA and EA groups. The rate of peritoneal recurrence was similar between the two groups (5.9% vs. 7.9%, p = 0.580).

CONCLUSIONS

The overall survival, disease-free survival, and the rate of peritoneal recurrence were comparable between the IA and EA procedures. IA ensures better recovery and comparable complications to EA and achieved a more precise tumor excision; thus, IA can be considered a safe procedure for patients with right-sided colon lesions.

Survival analysis of local excision vs total mesorectal excision for middle and low rectal cancer in pT1/pT2 stage and intermediate pathological risk

Background

Local excision (LE) is a feasible treatment approach for rectal cancers in stage pT1 and presents low pathological risk, whereas total mesorectal excision (TME) is a reasonable treatment for more advanced cancers. On the basis of the pathology findings, surgeons may suggest TME for patients receiving LE. This study compared the survival outcomes between LE with/without chemoradiation and TME in mid and low rectal cancer patients in stage pT1/pT2, with highly selective intermediate pathological risk.

Methods

This retrospective study included 134 patients who received TME and 39 patients who underwent LE for the treatment of intermediate risk (pT1 with poor differentiation, lymphovascular invasion, perineural invasion, relatively large tumor, or small-sized pT2 tumor) rectal cancer between 1998 and 2016.

Results

Overall survival (OS), disease-free survival (DFS), and cumulative recurrence rate (CRR) were similar between the LE (3-year DFS 92%) and TME (3-year DFS 91%) groups. Following subgrouping into an LE with adjuvant therapy group and a TME without adjuvant therapy group, the compared survival outcomes (OS, DFS, and CRR) were found not to be statistically different. The temporary and permanent ostomy rates were higher in the TME group than in the LE group (p < 0.001). Rates of early and late morbidity following surgery were higher in the TME group (p = 0.005), and LE had similar survival compared with TME.

Conclusion

For patients who had mid and low rectal cancer in stage pT1/pT2 and intermediate pathological risk, LE with chemoradiation presents an alternative treatment option for selected patients.

The dark side of laparoscopic surgery for colorectal cancer patients aged 75 years or older

PURPOSE

The rate of postoperative morbidity and mortality is reportedly high in patients aged ≥ 75 years with colorectal cancer (CRC). In such patients, a comparison of the short-term outcome between open method and laparoscopy has not been clearly defined in Taiwan. We aimed to compare postoperative morbidity and mortality parameters after open method and laparoscopy in CRC patients aged ≥ 75 years.

METHODS

We retrospectively analyzed patients who underwent surgery for CRC from February 2009 to September 2015 at the Linkou Chang Gung Memorial Hospital in Taiwan and analyzed their clinicopathological factors. Postoperative morbidity and mortality were analyzed for evaluating if laparoscopic surgery offers more favorable outcomes than open surgery in the elderly.

RESULTS

A total of 1133 patients were enrolled and analyzed in this study; they were divided into two groups (open method vs. laparoscopy = 797 vs. 336). The anastomotic leakage rate was significantly higher in the laparoscopy group than in the open method group (3.3 vs. 0.9%, p = 0.003). Overall postoperative morbidity and mortality rates showed no significant difference between these two groups. Postoperative hospital stay was significantly shorter in the laparoscopy group than in the open method group (10.4 ± 8.7 vs. 13.8 ± 13.5 days, p < 0.001).

CONCLUSIONS

Our results suggest that laparoscopy in patients aged ≥ 75 years with CRC had higher anastomosis leakage rate compared with open surgery but is acceptable and offers the benefit of a shorter hospital stay over open surgery.

The adenosine analogue N6-L-phenylisopropyladenosine inhibits catecholamine secretion from bovine adrenal medulla cells by inhibiting calcium influx

We reported earlier that adenine nucleotides and adenosine inhibit acetylcholine-induced catecholamine secretion from bovine adrenal medulla chromaffin cells. In this article, we used an adenosine analogue, N6-L-phenylisopropyladenosine (PIA), to study the mechanism underlying inhibition of catecholamine secretion by adenosine. PIA inhibits secretion induced by a nicotinic agonist, 1,1-dimethyl-4-phenylpiperazinium, or by elevated external K+. The half-maximal effect on 1,1-dimethyl-4-phenylpiperazinium-induced secretion occurred at approximately 5 x 10(-5) M. The inhibition is immediate and reversible. Fura-2 measurements of cytosolic free Ca2+ indicate that PIA inhibits Ca2+ elevation caused by stimulation; measurements of 45Ca2+ influx show that PIA inhibits uptake of Ca2+. PIA does not inhibit calcium-evoked secretion from digitonin-permeabilized cells, nor does PIA cause any significant change in the dependence of catecholamine secretion on calcium concentration. These data suggest that inhibition by PIA occurs at the level of the voltage-sensitive calcium channel.

Presence of Na+/Ca2+ exchange activity and its role in regulation of intracellular calcium concentration in bovine adrenal chromaffin cells

The presence of a Na+/Ca2+ exchanger in bovine adrenal chromaffin cells was demonstrated by measuring the efflux of 45Ca2+ which had been preloaded into cells by a brief depolarization. The efflux of 45Ca2+ was dependent on extracellular Na+ (Na+o); 45Ca2+ efflux was significantly decreased by replacing Na+o with N-methylglucamine (NMG), or Li+. Replacement of Na+o by NMG increased the resting intracellular Ca2+ concentration ([Ca2+]i) of freshly isolated chromaffin cells. This could be reversed by adding Na+, suggesting that Na+/Ca2+ exchanger activity was involved in maintaining [Ca2+]i at its resting level. The initial rate of Na(+)-dependent [Ca2+]i recovery after Ca2+ loading by depolarization was dependent on the level of [Ca2+]i. There was an apparent linear relationship between the activity of the Na+/Ca2+ exchanger and [Ca2+]i both in the presence and absence of Na+o. When cells were treated with other stimuli, including 10 microM DMPP or 40 mM caffeine, the ability of the stimulated cells to decrease [Ca2+]i was significantly reduced upon replacing Na+o with NMG. Our data show that the Na+/Ca2+ exchanger is one of the major pathways for regulating [Ca2+]i in chromaffin cells in both resting and stimulated states.

Structural role of amino acids 99-110 in recombinant human erythropoietin

Erythropoietin is the prime regulator of red blood cell production. Previous studies demonstrated that antipeptide antibodies to amino acids 99-119 and 111-129 bind to two non-overlapping domains and inhibit the hormone's action (Sytkowski, A.J. & Donahue, K. A. (1987) J. Biol. Chem. 262, 1161-1165). Oligonucleotide-directed mutagenesis now shows that amino acids 99-110 (domain 1) but not 119-129 (domain 2) are important to erythropoietin's structure and function. Mutagenesis of wild-type human erythropoietin cDNA was used to produce a series of mutant proteins with sequential deletion of three adjacent amino acids and insertion of the sequence Glu-Phe across the two domains. Transient expression in COS-7 cells revealed 2.0-kb transcripts encoded by all of the cDNAs. Domain 2 mutants exhibited specific biological activities similar to that of the wild type. In contrast, domain 1 mutants were not secreted. In vitro transcription and translation of the domain 1, domain 2 and wild-type cDNAs resulted in the isolation of 23.5-kDa and 32-kDa proteins in the absence or presence of pancreatic microsomes, respectively, consistent with efficient translation of all of the mutants and equivalent post-translational processing of each protein. The data suggest that mutation within domain 1 results in the intracellular biosynthesis of erythropoietins with altered structure, rendering them subject to rapid degradation. The bioassay of erythropoietins synthesized entirely in vitro demonstrated that domain 1 mutants were inactive, whereas both wild type and domain 2 mutant hormones exhibited biologic activity. The results are consistent with a critical role for amino acids 99-110 in the structure of human erythropoietin.

Induction of hemoglobin synthesis by downregulation of MYB protein with an antisense oligodeoxynucleotide

Reduced expression of the proto-oncogene c-myb appears necessary for erythroid differentiation induced by chemical agents and by the natural regulator, erythropoietin (Epo). Treatment of Epo-responsive Rauscher erythroleukemia cells with an anti-sense oligodeoxynucleotide to c-myb in the absence of other inducers downregulated myb protein markedly and caused hemoglobinization of the cells within 48 hours. Epo treatment, which downregulates c-myb in these cells, induced hemoglobinization to the same degree. Epo also induced the appearance of anion transport protein on the plasma membrane, consistent with terminal differentiation. In contrast, antisense c-myb did not induce this erythroid marker. The results are consistent with a role for myb protein in the regulation of hemoglobin synthesis.

Adenosine receptors activate adenylate cyclase and enhance secretion from bovine adrenal chromaffin cells in the presence of forskolin

Cells of the adrenal medulla release not only catecholamines but also high concentrations of neuropeptides and nucleotides. Chromaffin cells, like many neuronal cells, have a diversity of receptors: adrenergic receptors, peptide receptors, histamine receptors, and dopamine receptors. We recently reported that these cells have nucleotide receptors that can mediate inhibition of the secretory response. The present studies show that adenosine, in the presence of enabling concentrations of forskolin, can potently enhance response to nicotinic stimulation. Neither adenosine nor forskolin alone produces a significant effect. A marked rise in intracellular cyclic AMP (cAMP) concentration is associated with the enhancement of secretion caused by forskolin plus adenosine. A phosphodiesterase inhibitor, Ro 20-1724, used together with forskolin produces significant increases in both cellular cAMP content and catecholamine secretion. However, the adenosine agonist 5'-N-ethylcarboxyadenosine elevates cellular cAMP content in the presence of forskolin without having any positive effect on secretion. This finding suggests that the rise in cAMP level may not be the sole cause of the increase in secretion by adenosine.

Inhibition of catecholamine secretion from bovine chromaffin cells by adenine nucleotides and adenosine

ATP, ADP, and adenosine have been found to inhibit acetylcholine-stimulated secretion from isolated cells of bovine adrenal medulla (chromaffin cells). Maximal inhibition is approximately 30% under the conditions studied; half-maximal inhibition occurs at nucleotide concentration in the micromolar range. Cells must be incubated with ATP for approximately 90 s for maximal inhibition, but inhibition by adenosine occurs much faster, an observation suggesting the possibility that ATP and ADP exert their effect after being converted to adenosine. Experiments with cells preloaded with the fluorescent calcium chelator quin 2 indicate that external ATP can diminish the rise in cytosolic Ca2+ concentration that follows stimulation by acetylcholine.