Diabetes mellitus(DM)is still one of the most common diseases worldwide,and its prevalence is still increasing globally.According to the American and European recommendations,metformin is considered a first-line oral ...Diabetes mellitus(DM)is still one of the most common diseases worldwide,and its prevalence is still increasing globally.According to the American and European recommendations,metformin is considered a first-line oral hypoglycemic drug for controlling type 2 DM(T2DM)patients.Metformin is the ninth most often prescribed drug in the world,and at least 120 million diabetic people are estimated to receive the drug.In the last 20 years,there has been increasing evidence of vitamin B12 deficiency among metformin-treated diabetic patients.Many studies have reported that vitamin B12 deficiency is related to the malabsorption of vitamin B12 among metformin-treated T2DM patients.Vitamin B12 deficiency may have a very bad complication for the T2DM patient.In this review,we will focus on the effect of metformin on the absorption of vitamin B12 and on its proposed mechanisms in hindering vitamin B12 absorption.In addition,the review will describe the clinical outcomes of vitamin B12 deficiency in metformintreated T2DM.展开更多
To date,metformin remains the first-line oral glucose-lowering drug used for the treatment of type 2 diabetes thanks to its well-established long-term safety and efficacy profile.Indeed,metformin is the most widely us...To date,metformin remains the first-line oral glucose-lowering drug used for the treatment of type 2 diabetes thanks to its well-established long-term safety and efficacy profile.Indeed,metformin is the most widely used oral insulinsensitizing agent,being prescribed to more than 100 million people worldwide,including patients with prediabetes,insulin resistance,and polycystic ovary syndrome.However,over the last decades several observational studies and meta-analyses have reported a significant association between long-term metformin therapy and an increased prevalence of vitamin B12 deficiency.Of note,evidence suggests that long-term and high-dose metformin therapy impairs vitamin B12 status.Vitamin B12(also referred to as cobalamin)is a water-soluble vitamin that is mainly obtained from animal-sourced foods.At the cellular level,vitamin B12 acts as a cofactor for enzymes that play a critical role in DNA synthesis and neuroprotection.Thus,vitamin B12 deficiency can lead to a number of clinical consequences that include hematologic abnormalities(e.g.,megaloblastic anemia and formation of hypersegmented neutrophils),progressive axonal demyelination and peripheral neuropathy.Nevertheless,no definite guidelines are currently available for vitamin B12 deficiency screening in patients on metformin therapy,and vitamin B12 deficiency remains frequently unrecognized in such individuals.Therefore,in this“field of vision”article we propose a list of criteria for a cost-effective vitamin B12 deficiency screening in metformin-treated patients,which could serve as a practical guide for identifying individuals at high risk for this condition.Moreover,we discuss additional relevant topics related to this field,including:(1)The lack of consensus about the exact definition of vitamin B12 deficiency;(2)The definition of reliable biomarkers of vitamin B12 status;(3)Causes of vitamin B12 deficiency other than metformin therapy that should be identified promptly in metformin-treated patients for a proper differential diagnosis;and(4)Potential pathophysiological mechanisms underlying metformin-induced vitamin B12 deficiency.Finally,we briefly review basic concepts related to vitamin B12 supplementation for the treatment of vitamin B12 deficiency,particularly when this condition is induced by metformin.展开更多
AIM:To evaluate the effect of vitamin B12 deficiency anemia(BDA)on peripapillary retinal nerve fiber layer thickness(RNFLT)using spectral domain optical coherence tomography(SD-OCT),and to determine any correlation ar...AIM:To evaluate the effect of vitamin B12 deficiency anemia(BDA)on peripapillary retinal nerve fiber layer thickness(RNFLT)using spectral domain optical coherence tomography(SD-OCT),and to determine any correlation arising thereof.METHODS:In this cross-sectional observational study,99 eyes of 50 BDA patients of age 18-65 y were compared with 100 eyes of 50 healthy control subjects.All subjects underwent comprehensive clinical,ophthalmic,and hematological evaluation,followed by peripapillary RNFLT assessment using SD-OCT.RESULTS:The mean total,inferior,nasal,and temporal RNFLT were significantly lower in BDA group as compared to control group(P<0.05).The mean total,inferior and nasal RNFLT correlated significantly(P<0.05)with serum Hb%,B12 and mean corpuscular volume(MCV)level(r=0.310,0.435,-0.386 for total;r=0.932,0.481,-0.513 for inferior;r=0.344,0.254,-0.233 for nasal;respectively),while temporal and superior RNFLT quadrant did not show any correlation with any of the hematological parameters(r=0.144,0.167,-0.096;r=0.111,0.070,-0.099;respectively).The mean total RNFLT showed progressive thinning at par with the progression of anemia,except in very severe BDA,where an inverse relationship was documented.CONCLUSION:The mean total,inferior,nasal,and temporal peripapillary RNFLT was significantly thinner in BDA patients.Peripapillary RNFLT thinning seemed to proceed at par with the progression of severity of anemia,except in very sever grade.Early assessment of peripapillary RNFLT may be crucial in BDA patients to prevent potential blinding sequelae.Peripapillary RNFLT thinning in BDA patients should be considered in the differential diagnosis of other non-glaucomatous optic neuropathies,as well.展开更多
AIM:To study the association between Helicobacter pylori(H.pylori)infection and autoimmune type atrophic gastritis. METHODS:Twenty-three patients with different grades of atrophic gastritis were analysed using enzyme ...AIM:To study the association between Helicobacter pylori(H.pylori)infection and autoimmune type atrophic gastritis. METHODS:Twenty-three patients with different grades of atrophic gastritis were analysed using enzyme immunoassay-based serology,immunoblot-based serology,and histology to reveal a past or a present H.pylori infection.In addition,serum markers for gastric atrophy(pepsinogenⅠ,pepsinogenⅠ/Ⅱand gastrin)and autoimmunity[parietal cell antibodies(PCA), and intrinsic factor(IF),antibodies]were determined. RESULTS:Of the 14 patients with severe gastricatrophy,as demonstrated by histology and serum markers,and no evidence for an ongoing H.pylori infection,eight showed H.pylori antibodies by immunoblotting.All eight had elevated PCA and 4/8 also had IF antibodies.Of the six immunoblot-negative patients with severe corpus atrophy,PCA and IF antibodies were detected in four.Among the patients with low to moderate grade atrophic gastritis(all except one with an ongoing H.pylori infection),serum markers for gastric atrophy and autoimmunity were seldom detected.However,one H.pylori negative patient with mild atrophic gastritis had PCA and IF antibodies suggestive of a pre-atrophic autoimmune gastritis. CONCLUSION:Signs of H.pylori infection in autoimmune gastritis,and positive autoimmune serum markers in H.pylori gastritis suggest an etiological role for H.pylori in autoimmune gastritis.展开更多
Folate deficiency and its association with cancer have been studied in the literature, but its clinical impact is still unknown. Folate deficiency and its result on gastric cancer is a mysterious part of oncology, wit...Folate deficiency and its association with cancer have been studied in the literature, but its clinical impact is still unknown. Folate deficiency and its result on gastric cancer is a mysterious part of oncology, with ongoing studies hopefully clarifying its impact on gastric cancer management. Lee et al studied folate deficiency and its impact on staging and clinical results. Here we try to contribute to the field by expressing our own thoughts about the paper.展开更多
Background: Biermer disease is a megaloblastic disease caused by vitamin B12 deficiency. It is a rare clinical entity especially in subsahara Africa. Case presentation: We report the case of a 45 years old female pati...Background: Biermer disease is a megaloblastic disease caused by vitamin B12 deficiency. It is a rare clinical entity especially in subsahara Africa. Case presentation: We report the case of a 45 years old female patient who consulted for a one month history of generalised muscle cramps, weakness and numbness of all four limbs. Physical examination was relevant for a poor gait, poor coordination of both upper and lower limbs, a positive Romberg sign, normal muscle tone in all four limbs, reduced pallesthesia and deep tendon reflexes, abolished plantar reflexes. Paraclinical investigations revealed macrocytosis without anemia, a low cyanocobalamin (vitamin B<sub>12</sub>) level with a normal folic acid level, an atrophic corporeofundic mucosa which upon pathological analysis revealed a chronic atrophic gastritis with no Helicobacter pylori infection. Anti-intrinsic factor antibodies were positive while anti parietal cells antibodies were negative. The diagnosis of Biermer disease was considered and the patient did well on vitamin B<sub>12</sub> supplementation. Conclusion: Though a rare disease, Biermer disease should be considered in a patient who consults for polyneuropathy even in the absence of anemia.展开更多
文摘Diabetes mellitus(DM)is still one of the most common diseases worldwide,and its prevalence is still increasing globally.According to the American and European recommendations,metformin is considered a first-line oral hypoglycemic drug for controlling type 2 DM(T2DM)patients.Metformin is the ninth most often prescribed drug in the world,and at least 120 million diabetic people are estimated to receive the drug.In the last 20 years,there has been increasing evidence of vitamin B12 deficiency among metformin-treated diabetic patients.Many studies have reported that vitamin B12 deficiency is related to the malabsorption of vitamin B12 among metformin-treated T2DM patients.Vitamin B12 deficiency may have a very bad complication for the T2DM patient.In this review,we will focus on the effect of metformin on the absorption of vitamin B12 and on its proposed mechanisms in hindering vitamin B12 absorption.In addition,the review will describe the clinical outcomes of vitamin B12 deficiency in metformintreated T2DM.
文摘To date,metformin remains the first-line oral glucose-lowering drug used for the treatment of type 2 diabetes thanks to its well-established long-term safety and efficacy profile.Indeed,metformin is the most widely used oral insulinsensitizing agent,being prescribed to more than 100 million people worldwide,including patients with prediabetes,insulin resistance,and polycystic ovary syndrome.However,over the last decades several observational studies and meta-analyses have reported a significant association between long-term metformin therapy and an increased prevalence of vitamin B12 deficiency.Of note,evidence suggests that long-term and high-dose metformin therapy impairs vitamin B12 status.Vitamin B12(also referred to as cobalamin)is a water-soluble vitamin that is mainly obtained from animal-sourced foods.At the cellular level,vitamin B12 acts as a cofactor for enzymes that play a critical role in DNA synthesis and neuroprotection.Thus,vitamin B12 deficiency can lead to a number of clinical consequences that include hematologic abnormalities(e.g.,megaloblastic anemia and formation of hypersegmented neutrophils),progressive axonal demyelination and peripheral neuropathy.Nevertheless,no definite guidelines are currently available for vitamin B12 deficiency screening in patients on metformin therapy,and vitamin B12 deficiency remains frequently unrecognized in such individuals.Therefore,in this“field of vision”article we propose a list of criteria for a cost-effective vitamin B12 deficiency screening in metformin-treated patients,which could serve as a practical guide for identifying individuals at high risk for this condition.Moreover,we discuss additional relevant topics related to this field,including:(1)The lack of consensus about the exact definition of vitamin B12 deficiency;(2)The definition of reliable biomarkers of vitamin B12 status;(3)Causes of vitamin B12 deficiency other than metformin therapy that should be identified promptly in metformin-treated patients for a proper differential diagnosis;and(4)Potential pathophysiological mechanisms underlying metformin-induced vitamin B12 deficiency.Finally,we briefly review basic concepts related to vitamin B12 supplementation for the treatment of vitamin B12 deficiency,particularly when this condition is induced by metformin.
文摘AIM:To evaluate the effect of vitamin B12 deficiency anemia(BDA)on peripapillary retinal nerve fiber layer thickness(RNFLT)using spectral domain optical coherence tomography(SD-OCT),and to determine any correlation arising thereof.METHODS:In this cross-sectional observational study,99 eyes of 50 BDA patients of age 18-65 y were compared with 100 eyes of 50 healthy control subjects.All subjects underwent comprehensive clinical,ophthalmic,and hematological evaluation,followed by peripapillary RNFLT assessment using SD-OCT.RESULTS:The mean total,inferior,nasal,and temporal RNFLT were significantly lower in BDA group as compared to control group(P<0.05).The mean total,inferior and nasal RNFLT correlated significantly(P<0.05)with serum Hb%,B12 and mean corpuscular volume(MCV)level(r=0.310,0.435,-0.386 for total;r=0.932,0.481,-0.513 for inferior;r=0.344,0.254,-0.233 for nasal;respectively),while temporal and superior RNFLT quadrant did not show any correlation with any of the hematological parameters(r=0.144,0.167,-0.096;r=0.111,0.070,-0.099;respectively).The mean total RNFLT showed progressive thinning at par with the progression of anemia,except in very severe BDA,where an inverse relationship was documented.CONCLUSION:The mean total,inferior,nasal,and temporal peripapillary RNFLT was significantly thinner in BDA patients.Peripapillary RNFLT thinning seemed to proceed at par with the progression of severity of anemia,except in very sever grade.Early assessment of peripapillary RNFLT may be crucial in BDA patients to prevent potential blinding sequelae.Peripapillary RNFLT thinning in BDA patients should be considered in the differential diagnosis of other non-glaucomatous optic neuropathies,as well.
文摘AIM:To study the association between Helicobacter pylori(H.pylori)infection and autoimmune type atrophic gastritis. METHODS:Twenty-three patients with different grades of atrophic gastritis were analysed using enzyme immunoassay-based serology,immunoblot-based serology,and histology to reveal a past or a present H.pylori infection.In addition,serum markers for gastric atrophy(pepsinogenⅠ,pepsinogenⅠ/Ⅱand gastrin)and autoimmunity[parietal cell antibodies(PCA), and intrinsic factor(IF),antibodies]were determined. RESULTS:Of the 14 patients with severe gastricatrophy,as demonstrated by histology and serum markers,and no evidence for an ongoing H.pylori infection,eight showed H.pylori antibodies by immunoblotting.All eight had elevated PCA and 4/8 also had IF antibodies.Of the six immunoblot-negative patients with severe corpus atrophy,PCA and IF antibodies were detected in four.Among the patients with low to moderate grade atrophic gastritis(all except one with an ongoing H.pylori infection),serum markers for gastric atrophy and autoimmunity were seldom detected.However,one H.pylori negative patient with mild atrophic gastritis had PCA and IF antibodies suggestive of a pre-atrophic autoimmune gastritis. CONCLUSION:Signs of H.pylori infection in autoimmune gastritis,and positive autoimmune serum markers in H.pylori gastritis suggest an etiological role for H.pylori in autoimmune gastritis.
文摘Folate deficiency and its association with cancer have been studied in the literature, but its clinical impact is still unknown. Folate deficiency and its result on gastric cancer is a mysterious part of oncology, with ongoing studies hopefully clarifying its impact on gastric cancer management. Lee et al studied folate deficiency and its impact on staging and clinical results. Here we try to contribute to the field by expressing our own thoughts about the paper.
文摘Background: Biermer disease is a megaloblastic disease caused by vitamin B12 deficiency. It is a rare clinical entity especially in subsahara Africa. Case presentation: We report the case of a 45 years old female patient who consulted for a one month history of generalised muscle cramps, weakness and numbness of all four limbs. Physical examination was relevant for a poor gait, poor coordination of both upper and lower limbs, a positive Romberg sign, normal muscle tone in all four limbs, reduced pallesthesia and deep tendon reflexes, abolished plantar reflexes. Paraclinical investigations revealed macrocytosis without anemia, a low cyanocobalamin (vitamin B<sub>12</sub>) level with a normal folic acid level, an atrophic corporeofundic mucosa which upon pathological analysis revealed a chronic atrophic gastritis with no Helicobacter pylori infection. Anti-intrinsic factor antibodies were positive while anti parietal cells antibodies were negative. The diagnosis of Biermer disease was considered and the patient did well on vitamin B<sub>12</sub> supplementation. Conclusion: Though a rare disease, Biermer disease should be considered in a patient who consults for polyneuropathy even in the absence of anemia.
